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Occupational Health News Roundup

kkrisberg — Fri, 30 Jun 2017 17:12:17 +0000

Occupational Health News Roundup

At the Center for Public Integrity, a five-part investigative series on safety at the nation’s nuclear facilities finds that workers can and do suffer serious injuries, yet the Department of Energy typically imposes only minimal fines for safety incidents and companies get to keep a majority of their profits, which does little to improve working conditions. Reporters estimated that the number of safety incidents has tripled since 2013.

For example, in 2009, the chair of a safety committee at Idaho National Laboratory told high-ranking managers that damaged plutonium plates could put workers at serious risk. However, managers ignored his warnings. Then an incident occurred in which 16 workers inhaled plutonium dust particles.

In Part 5 of the series, Patrick Malone and Peter Cary write:

Ted Lewis knew the plutonium plates at the government lab where he worked could leak potentially lethal radioactive dust.

He had seen it occur in the 1970s, when he was helping load some of those plates into a nuclear reactor at the lab near Idaho Falls, Idaho. A steel jacket enclosing one of the plates somehow cracked, spilling plutonium oxide particles into the air. But Lewis and his colleagues were lucky — they were wearing respirators and given cleansing showers, so their lives weren’t endangered.

Three decades later, Lewis, an electrical engineer who had become chairman of the lab’s safety committee, had a bad feeling this could happen again, with a worse outcome. And he turned out to be right.

He tried to head it off. In 2009, Lewis wrote a pointed warning memo — he called it a White Paper — and gave it to the official in charge of all nuclear operations at the Idaho National Laboratory, which is run by a consortium of private companies and universities under contract to the Energy Department.

The memo said the chance of encountering a plutonium plate that disintegrated, as Lewis had previously witnessed, was “greater than facility and senior management realizes,” according to a copy. Although Lewis said that a workplace manual published by the contractor — Battelle Energy Alliance, LLC (BEA) — called the risk of an accidental spill of such radioactive dust “negligible,” he wanted his superiors to expect it and prepare for it.

He said in a sworn court deposition in January 2016 that he shared his concerns with at least 19 others at the laboratory, which holds one of the world’s largest stockpiles of plutonium, the explosive at the heart of modern nuclear weapons. But they didn’t respond, he said, and some of the precautions he urged — checking the plates more carefully before they were unwrapped and repackaged for shipment and setting up a decontamination shower — were ignored.

Read the full (and amazing) investigative series at the Center for Public Integrity.

In other news:

USA Today: Brett Murphy reports on a year-long investigation into port trucking companies in Southern California, finding that such companies often treat their workers like little more than indentured servants, forcing drivers to take on huge debt to finance their own trucks and then using that debt against them to “trap drivers in jobs that left them destitute.” When drivers quit, the companies seize their trucks, keeping all the money the workers had paid toward ownership. Drivers also reported being physically barred from going home, being forced to work against their will, and being forced to break safety laws that limit the hours they drive each day. The investigative piece is based on accounts from more than 300 drivers, hundreds of hours of sworn testimony and contracts never seen by the public. Murphy writes: “Retailers could refuse to allow companies with labor violations to truck their goods. Instead they’ve let shipping and logistics contractors hire the lowest bidder, while lobbying on behalf of trucking companies in Sacramento and Washington D.C. Walmart, Target and dozens of other Fortune 500 companies have paid lobbyists up to $12.6 million to fight bills that would have held companies liable or given drivers a minimum wage and other protections that most U.S. workers already enjoy.”

Huffington Post: Jesselyn Cook reports that seven journalists have been murdered in Mexico this year, which means Mexico is now among the most dangerous places to be a reporter. The most recent victim was Salvador Adame, a veteran TV reporter who covered regional news and politics. Months before Adame’s death, reporter Miroslava Breach Velducea, a reporter for La Jornada, was shot eight times outside her home in front of her children. Unfortunately, the killing of journalists in Mexico often goes unpunished. Cook writes: ‘“Fear and self-censorship by journalists remains very, very strong,’ Emmanuel Colombié, Latin America director for Reporters Without Borders (or Reporters sans frontières), told HuffPost. Some reporters have fled Mexico and others have quit the industry as a result of targeted threats and violence against members of the Mexican press, he noted. In the border state of Tamaulipas, for example, ‘there are very few journalists remaining,’ Colombié said.”

High Plains Public Radio: Grant Gerlock reports that a new Government Accountability Office (GAO) report finds that the safety data collected by federal officials doesn’t accurately reflect all the dangers that meat and poultry workers face on the job. According to the GAO report, 151 meat and poultry workers died from on-the-job injuries between 2004 and 2013, which means such workers experience a higher injury rate than their peers in the rest of the manufacturing industry. However, the GAO also found that such injuries are under-reported. For example, injuries among sanitary workers who clean meat plant machinery aren’t always counted as official meat and poultry workers. In addition, some injured workers are simply encouraged to return to work without seeing a doctor. Gerlock writes: “Worker advocates say they have long been suspicious of reported injury rates from meat companies. For instance, a recent study at a Maryland poultry plant by the National Institute for Occupational Safety and Health found one-third of workers had injuries that meet the definition of carpal tunnel, but only a handful of injuries had been reported to the Occupational Safety and Health Administration.”

American Prospect: David Bacon reports that after four years of strikes and boycotts, the first new U.S. farmworker union in 25 years has officially launched: Familias Unidas por la Justicia (FUJ) in Washington state. The union’s origins go back to 2013, when workers at Sakuma Brothers Farms grew angry about low piece rates and poor conditions in the labor camps. Workers then discovered that employers had begun recruiting workers via the H2A visa program and paying them nearly $3 more an hour than local workers, even though the visa program is supposed to be for employers unable to find workers locally. Eventually, the employers attempted to fire the entire workforce and replace them with H2A workers. The plan backfired after workers exposed the scheme, paving the way for a union. Bacon reports: “’We are part of a movement of indigenous people,’ says Felimon Pineda, FUJ vice president. An immigrant from Jicaral Cocoyan de las Flores in Oaxaca, he says organizing the union is part of a fight against the discrimination indigenous people face in both Mexico and the United States: ‘Sometimes people see us as being very low. They think we have no rights. They're wrong. The right to be human is the same.’”

Kim Krisberg is a freelance public health writer living in Austin, Texas, and has been writing about public health for 15 years. Follow me on Twitter — @kkrisberg.

kkrisberg Fri, 06/30/2017 - 13:12

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Occupational Health News Roundup

kkrisberg — Tue, 07 Jun 2016 16:24:37 +0000

Occupational Health News Roundup

At Reveal, Jennifer LaFleur writes about the U.S. veterans who witnessed the country’s many nuclear weapon tests, the health problems they’ve encountered in the decades since their service, and their fight for compensation. One of the “atomic veterans” LeFleur interviewed — Wayne Brooks — said: “We were used as guinea pigs – every one of us. They didn’t tell us what it was gonna do to us. They didn’t tell us that we were gonna have problems later on in life with cancers and multiple cancers.” LaFleur writes:

All of the atomic vets were sworn to secrecy. Until the secrecy was lifted decades later, they could not tell anyone about their experiences. Even if they became ill, they could not tell doctors they might have been exposed to radiation.

Scientists had known from the earliest days of building the atomic bomb that radiation posed risks. Research found increased rates of certain cancers among the survivors of the Japanese bombings. It also showed that the children of survivors were more likely to have smaller heads and physical disabilities.

But there never was a coordinated attempt to study or track the health effects of radiation on the atomic vets or their children.

“They never used the knowledge that they could have gotten from us,” Brooks said. “They could have watched us all our lives and seen what it did, but they didn’t. They dropped us like a hot potato.”

LaFleur also reports about impacts on the families of atomic veterans. She interviewed Navy veteran Lincoln Grahlfs, 93, an atomic vet who was assigned to work a series of nuclear tests in the Marshall Islands. She writes of Grahlfs:

He knows that he is fortunate to be alive, despite health problems that include several bouts with skin cancer and prostate cancer over the years.

Grahlfs gets about $650 per month in compensation for skin cancer. He applied for compensation in August 2012, though it took nearly two years for the money to show up.

His bigger concern is what his exposure might have done to his children and grandchildren.

Grahlfs’ daughter suffered from endocrine problems throughout her teenage years and died of a malignant brain tumor in 1996 at 46. One son has bipolar disorder. Another has Addison’s disease, a rare adrenal condition. His granddaughter was born with a deformed foot.

“That’s a pretty full plate for somebody who never had any history of any of these things in my family,” Grahlfs said.

To read the full investigation, visit Reveal.

In other news:

The Hill: Lydia Wheeler reports that the Department of Labor is proposing new rules to improve miner safety. The proposed rules would require mining companies to examine the worksite before miners begin working and notify miners of any issues that may impact their safety and health. The examination records would then be made available to federal inspectors and worker representatives. Wheeler writes: “Under current (Mine Safety and Health Administration) standards, a workplace examination can be conducted at any time during a shift. But the rules in place now do not specify what information should be included or require mine operators to promptly notify miners when adverse conditions are found.“

Washington Post: Aaron Davis reports that the District of Columbia City Council has approved a measure to raise the city’s minimum wage to $15, and the city’s mayor is expected to sign it into law. Currently, D.C.’s minimum wage is $10.50; the new law would up that wage to $15 by 2020, after which increases would be automatic and tied to inflation. Tipped workers’ base rate would rise from $2.77 to $5, and employers would have to make up the difference if a worker’s tips don’t get him or her to the $15/hour mark. Davis writes: “But representatives of the Restaurant Opportunities Center said they were not ready to abandon the goal of a $15 minimum for restaurant workers. Kennard Ray, a spokesman for the group, said he was disappointed that D.C. lawmakers had ‘chosen again to leverage some low-wage workers against others’ to make a deal on minimum-wage law.”

New York Post: Emily Saul reports that a construction company owner is now facing manslaughter charges in the death of worker Vidal Sanchez Ramon, 50, who fell from the sixth floor of a commercial building site in Coney Island. Local building codes require that workers wear harnesses and that elevated working areas have protective rails — both of which were not the case at the building site where Ramon died. Saul reports: “A hardworking man died tragically and unnecessarily because proper safety measures were not taken to protect his life,” Brooklyn DA Ken Thompson said in a statement. “As buildings go up all over Brooklyn, we owe it to every construction worker to make sure that they don’t lose their lives due to short cuts on safety.”

Gawker: The online media outlet published a first-person account of an Amazon worker in California who worked in a “cross dock” warehouse, which is devoted to preparing products for other vendors. (This is in contrast to an Amazon fulfillment center, where workers fulfill actual customer orders.) The anonymous worker writes about having to make “rate” — or unpacking and repacking a certain number of products per hour. At first, the worker writes, the rate was 85, but then it rose to 180. According to the article: “Rate was constant. Rate was on you all day. If you went to the bathroom, that lowered your Rate. If your boss came by to see how you were doing, that distraction lowered your Rate. If you ran out of bags and had to go get new ones yourself, that lowered your Rate. If you cut yourself on a box cutter or pinched a finger in the conveyor belt right next to you or something, and had to go to the on-site Amcare office (like a school nurse’s office, and equally as competent), well, you were still on Rate, and that lapse in work lowered your Rate.”

Kim Krisberg is a freelance public health writer living in Austin, Texas, and has been writing about public health for nearly 15 years.

kkrisberg Tue, 06/07/2016 - 12:24

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UPDATE Chance Typhoon Neoguri Will Hit Nuke Plant Increases?

gregladen — Mon, 07 Jul 2014 14:37:49 +0000

UPDATE Chance Typhoon Neoguri Will Hit Nuke Plant Increases?

Update:

The new forecast track of Neoguri is shown above as well as the location of two nuclear power plants.

The forecast track has moved south, and is now in a very good (and here good means bad) position to strike the Sendai nuclear power plant very directly. Keep in mind that this forecast may change.

On Tuesday mid day UTC the storm will likely be in the later phases of a turn to the right, aiming roughly at the Sendai plant. At this point maximum wind speed near the center of the storm will likely be about 90 mph, which puts the storm in the middle of the Category One range. That evening, possibly near midnight, the center of the typhoon should be coming ashore. During this time the storm will weaken.

The exact track matters a lot. It is quit possible that the right front quadrant, near the eye, will come ashore very near the plant, which would mean a very severe storm tide. But, the strength of the storm will be attenuated so perhaps the storm tide will be reduced.

Even though the storm now seems to be more or less aiming at a shut-down nuclear power plant, I'm thinking this will all result in little more than a very wet nuclear power plant. If the storm was stronger I'd be more worried about the effects of storm surge. I think Japan will have other problems caused by this storm to worry about.

Old post:

Yes and no. The question really has to be understood to refer to a "meaningful" hit, one that matters to the plant.

Yes because Super Typhoon Neoguri (which means "raccoon" in Korean) is on its way to Japan and there is no way that at least two nuclear power plants, those facing the southwest in the vicinity where the Typhoon is likely to make its first major landfall, will not be affected by this storm because the storm is huge. It is going to hit everything.

No because it is possible Neoguri will not be a Category Five storm when it hits this part of Japan, it is more likely to be a Category Two storm by then.

Maybe, because the currently predicted path of Neoguri, as indicated on the graphic above, is highly uncertain at any level of detail at this time. It is quite possible that the right punch (right leading quadrant) of the storm, and thus the storm tide, will come ashore in a bad place. In this situation, the bad place would be at Sendai ... Genkai is probably more protected. But the storm could come assure in a lot of places, we just don't know yet.

No, because even if there is something of a direct hit, the Japanese nuclear authorities have ashore us that the plants, which are all shut down, are secured and can easily handle this.

Maybe yes because if you accept what the Japanese Nuclear Power authorities say at face value you are a moron. That should be obvious by now.

In the end, though, I do think that nuclear power plants are generally well built and secured and I'm sure a big storm won't bother them too much. But, even if shut down, as they are, cooling of fuel is still required and a major storm could do the kind of damage that interferes with that. So we'll see. The chances, though, of a nuclear disaster related to this particular storm are minimal. The storm itself is the problem.

There is some great coverage on the storm here:

‘Once In Decades’ Typhoon Approaches Japan, Two Nuclear Power Plants

A Scary Super Typhoon Is Bearing Down on Japan…and Its Nuclear Plants

gregladen Mon, 07/07/2014 - 10:37

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Occupational Health News Roundup

lborkowski — Tue, 18 Mar 2014 07:43:37 +0000

Occupational Health News Roundup

Three years after Japan's earthquake and tsunami led to the Fukushima Daiichi nuclear disaster, concerns persist about health effects while the cleanup poses ongoing health and safety challenges.

Living on Earth reports on a lawsuit filed by several US Navy sailors against the Tokyo Electric Power Company (Tepco). The sailors were part of a relief operation, and their ship sailed into a plume of radioactive dust. Their attorney, Charles Bonner, told Living on Earth that many sailors are now suffering from “leukemias, ulcers, brain tumors, testicular cancers, dysfunctional uterine bleeding, thyroid problems.” The lawsuit seeks medical damages from Tepco on the grounds that it failed to warn the Navy about the radiation threat the company knew existed.

The New York Times reports that with many workers unwilling to undertake hazardous decommissioning work at the damaged Fukushima Daiichi nuclear facility, labor brokers are recruiting destitute workers with limited skills and training. Those who manage the operations often fail to provide appropriate training and oversight, which puts the workers at risk and can also endanger the public. Hiroko Tabuchi writes:

Regulators, contractors and more than 20 current and former workers interviewed in recent months say the deteriorating labor conditions are a prime cause of a string of large leaks of contaminated water and other embarrassing errors that have already damaged the environment and, in some cases, put workers in danger. In the worst-case scenario, experts fear, struggling workers could trigger a bigger spill or another radiation release.

“There is a crisis of manpower at the plant,” said Yukiteru Naka, founder of Tohoku Enterprise, a contractor and former plant engineer for General Electric. “We are forced to do more with less, like firemen being told to use less water even though the fire’s still burning.”

That crisis was especially evident one dark morning last October, when a crew of contract workers was sent to remove hoses and valves as part of a long-overdue upgrade to the plant’s water purification system.

According to regulatory filings by Tepco, the team received only a 20-minute briefing from their supervisor and were given no diagrams of the system they were to fix and no review of safety procedures — a scenario a former supervisor at the plant called unthinkable. Worse yet, the laborers were not warned that a hose near the one they would be removing was filled with water laced with radioactive cesium.

Multiple layers of contractors are often present between the workers and Tepco, which critics say allows the company to evade responsibility.

In other news:

New York Times: McDonald's workers in California, Michigan, and New York filed lawsuits agains the company and franchise owners over wage theft. Workers allege that their bosses failed to pay them for hours worked, required them to pay for uniforms even though doing so reduced their wages to below the federal minimum, and failed to pay required overtime wages.

Houston Chronicle: A Houston Chronicle investigation found that Texas oil and gas companies with multiple worker fatalities haven’t made it onto the Occupational Safety and Health Administration’s Severe Violator Enforcement Program list.

Slate: In a 97-0 vote, the Senate passed a bill changing the military's sexual assault policies; the bill was authored by a bipartisan group of Senators - Claire McCaskill (D-MO), Kelly Ayotte (R-NH) and Deb Fischer (R-NE) - and ends the practice of allowing a "good soldier" defense for members of the military accused of sexual assault. The bill passed after a competing bill by Senator Kirsten Gillibrand (D-NY) to move prosecutory authority outside the chain of command received 55 votes -- a majority of the chamber, but not enough to overcome the filibuster. (This Washington Post piece describes the bill in greater detail.)

Washington Post's Wonkblog: At the Nissan plant in Smyrna, Tennessee, some workers are employed directly by the company while others work for an in-house contractor and earn about half as much as the Nissan employees. One of the contract workers who struggles to get by on his lower wage tells the Post, "you're so exhausted from working seven days a week, you're dependent on some drug to stay awake, or dependent on some drug to go asleep, or for pain."

Center for Public Integrity: Sri Lanka has ordered a ban on glyphosate, the active ingredient in Monsanto's Roundup herbicide, after a new study suggested that the combination of glyphosate and heavy mentals in drinking water may cause the chronic kidney disease that's been killing agricultural workers in Central America and Sri Lanka.

lborkowski Tue, 03/18/2014 - 03:43

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Binding Energy, Nuclear Physics, and Radiation Poisoning

esiegel — Wed, 13 Nov 2013 19:31:01 +0000

Binding Energy, Nuclear Physics, and Radiation Poisoning

"Ours is a world of nuclear giants and ethical infants. We know more about war that we know about peace, more about killing that we know about living." -Omar N. Bradley

Nuclear physics is one of the most daunting, emotionally charged phrases in all of science. You can hardly say the words without the image of a mushroom cloud popping into most people's heads, followed by the devastations of radiation sickness and lingering radioactivity.

Image credit: National Archives image (208-N-43888), Charles Levy, of the Nagasaki bomb.

But -- as a physicist -- that's not what I think of at all.

Think down to all the basic constituents of matter, down beneath your cells, your organelles, the molecules that make them up all the way down to the individual atoms that make up the elements of everything on Earth.

Image credit: CC 3.0, via https://grade-56g.wikispaces.com/.

At the heart of every atom is an atomic nucleus made up of some combination of protons and neutrons, which in turn are made up of even more fundamental particles known as quarks and gluons. When I think of nuclear physics, I think of tremendous numbers of these little guys -- Avogadro's Number's worth of them -- and how they combine together on the smallest scales.

Image credit: Lawrence Berkeley National Laboratory.

At the most fundamental level (that we know of), the quarks and gluons bind together, with three quarks making up each and every nucleon, where a nucleon is a general term for either a proton or a neutron.

Neutrons and protons aren't just made up of three quarks apiece, though, and you might have guessed that if you looked up the masses of the quarks and the masses of protons and neutrons.

Image credit: http://cronodon.com/ (L), Fermilab / D0 (R).

We typically say that a proton is made up of two up and one down quark, and that a neutron is made up of one up and two downs. But an up quark has a mass of about 4-5 MeV (in natural units) and a down has a mass of 7-8 MeV; based on that, you might think a proton has a mass of around 17 MeV and a neutron at around 19 MeV.

Those guesses are reasonable, and yet they're only about 2% of the actual proton and neutron masses, which are about 938 MeV and 940 MeV, respectively. Where does the rest of that mass come from?

Image credit: Alex Dzierba, Curtis Meyer and Eric Swanson.

From binding energy. Those numbers I gave you for quark masses are for theoretically free quarks, which aren't bound at all to anything else. But -- at least in the Universe's current state -- free quarks can't exist, thanks to the rules of Quantum Chromodynamics, the laws that govern the strong force! Quarks can only stably exist in bound states, and the only bound states of quarks that are stable for longer than a microsecond are protons and neutrons.

So most of the energy that we observe as "mass" in a proton or neutron doesn't come from the masses of the three quarks that define the nucleon themselves, but rather from the field of the strong force that keeps them bound together. Another way of looking at it is to consider the gluons and the sea of virtual particles (quarks and antiquarks of all types) that make up each nucleon as what really makes the mass of a proton or neutron as heavy as it is.

Image credit: Matt Strassler of http://profmattstrassler.com/.

Which is to say, to have something just as simply as one proton or one neutron, there's a lot more involved than just three quarks. In fact those three quarks that you hear of as making up a proton or neutron are more specifically known as valence quarks, and all the other quarks-and-antiquarks inside are known as sea quarks, which carry some 98% of the masses of these particles.

But with the sole exception of a single proton (which serves as a common hydrogen nucleus), these nucleons don't exist in isolation in nature.

Image credit: CERN / European Organization for Nuclear Research, http://www.physik.uzh.ch/.

They exist in states where they're bound to one another. That's what makes atoms interesting: the fact that they have different numbers of protons (which makes for different elements) and different numbers of neutrons (which makes for different isotopes). And unsurprisingly, each unique combination of protons and neutrons has a unique binding energy, and only a very select few combinations are stable.

Image credit: I. Cullen at http://personal.ph.surrey.ac.uk/.

The simplest combination -- one proton and one neutron -- is known as a deuteron, and is about 2.2 MeV lighter than a free proton and neutron alone. Start adding more, like two protons and two neutrons (to make Helium-4), and you're suddenly 28 MeV lighter than those four free particles. The most stable of all the elements is Iron-56, with 26 protons and 30 neutrons, and which has a mass that's a full 492 MeV lighter than 26 free protons and 30 free neutrons.

Heavier elements and isotopes may have a larger total binding energy, but no element has a higher binding-energy-per-nucleon than this isotope of iron.

Image credit: Pearson Prentice Hall, modified by University of Wisconsin Stevens Point.

Low-mass particles are easy to fuse into higher-mass ones; they emit a lot of energy when they do so. So long as you can achieve sufficient temperatures and densities, this is something that happens spontaneously, and is both the great hope of commercial nuclear fusion and also how all the elements in the Universe heavier than lithium were produced: in the nuclear fusion furnaces of stars!

Image credit: Catherine Michelle Deibel's Ph.D. Thesis.

On the other hand, (mostly heavier) particles that have too little binding-energy-per-nucleon can spontaneously undergo one of three radioactive decays to reach a more stable state:

Gamma decay, where a nucleus emits a gamma-ray (high-energy photon) to form a slightly lower-mass nucleus with the same number of protons and neutrons;
Beta decay, where a nucleus emits an electron (and an antineutrino) to form a nucleus with a slightly lower mass, with one more proton and one fewer neutron than its parent nucleus;
and Alpha decay, where a nucleus emits a Helium-4 nucleus (two protons and two neutrons, known as an alpha particle), and results in a nucleus with a lower mass, two fewer neutrons and two fewer protons than its parent.

These processes may be a one-off, as in the daughter nuclei they give rise to may be stable, or they may be part of a radioactive decay chain, which can require many steps until something stable is reached.

Image credit: Wikimedia Commons user Eugene Alvin Villar.

What's particularly interesting is that:

Each combination of protons and neutrons has a specific binding energy and therefore a specific rest mass,
but there are only three types of radioactive decay, each which gives rise to a photon (massless), electron (of a small, given mass) or an alpha particle (of a larger, given mass), and therefore
each radioactive element produces radioactive decays with specific, characteristic energies (and timescales) associated with them!

Each type of particle -- alpha, beta and gamma -- takes different types of material to stop them, and to shield sensitive things (like you and me) from them.

Image credit: Cameco.com.

Alpha particles are mostly harmless; they can be stopped by a sheet of paper, and even if they actually reach your body, are stopped by the outer one-or-two layers of skin cells on your epidermal layers.

Beta particles can do some damage; they can penetrate your skin and, in large doses, can give you radiation sickness and kill you.

But gamma particles are the most deadly: it takes a full foot (30 cm) of lead to effectively shield you from gamma radiation, and most cases of radiation sickness related to, say, the Hiroshima bomb came from gamma radiation.

But that's not all cases of radiation sickness.

Images credit: Alistair Fuller/AP (L), PA (R).

Alexander Litvinenko was famously poisoned by being forced to ingest a radioactive isotope of Polonium (Po-210), which is an alpha-emitting radioactive particle. Although alpha decay is harmless if it takes place outside of your body, inside of you, all of that radiation is absorbed internally, and death is inevitable within a matter of days. (This is true for ingesting sufficient quantities of any radioactive material with a short half-life!)

But there are some specific characteristics that allow us to determine just what it was that poisoned him.

Image credit: Nuclear Physics Laboratory, University of Cyprus.

When an alpha particle is emitted from a nucleus, it will have a specific amount of kinetic energy that's determined by the decay parent (Po-210 in this case) and the large, daughter nucleus (Pb-206, lead, which is stable). So when you want to determine whether there's a particular radioactive substance, you look for alpha particles with a certain energy, and that's a smoking gun for the radioactive parent.

There's a question burning up around the world right now: is this how Yasser Arafat died?

Image credit: Arabs48, via http://www.imemc.org/article/64141.

Although at this point I don't think anyone can say for sure, this is the type of detective work that will uncover the answer: nuclear physics! It's an incredibly powerful thing; used irresponsibly, it can kill hundreds of thousands in an instant or poison a targeted individual slowly and painfully, but used responsibly, it can be a practically infinite source of power for mankind.

It's to be respected and valued, and only feared in the wrong hands. No matter what, it's a great opportunity to understand our natural world a little better, and how matter on the smallest scales can impact the largest things we know!

esiegel Wed, 11/13/2013 - 14:31

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I've wondered, why do we usually talk of three kinds of radiation, and leave out the neutrons? It's one thing if we don't want to give them another Greek-letter name, but it does seem odd to leave them out of the count.

A few comments from a radiologist/nuclear medicine doc.

When MR imaging came on the scene in the early 80's, it was known, naturally enough, as NMR (nuclear magnetic resonance) imaging, since it derived from the physics used in every chemistry department, the NMR machine. Pretty quickly, the N was dropped purely for PR reasons.

There are a few therapeutic uses for alpha emitters. Primarily iodine -131 treatment for hyperthyroidism and thyroid cancers. The thyroid will take up about 25% of the entire dose of iodine given to a patient, with the rest being distributed throughout the body, and not causing any effect. The alpha particles deposit their ~ 1Mev of energy within a mm or 2 of the site of decay (the thyroid cell) and as a result essentially burn the tissue. This treatment has been around since about the late 40's and is incredibly effective. Also, since the effect is only on the very immediate area, it is incredibly safe. If only we had more like it.
Strontium 89 is used in a similar manner to treat bone metastasis, typically from prostate cancer. It will relieve pain, but not cure the lesions.
There have been other efforts to specifically target pathologic tissue, using, for example, I-131 labelled antibodies, but the antibodies to the tumor do not target the tumors specifically enough to be useful.
There is another decay mode not mentioned in the text, and that is positron decay. Most of the lighter elements, which tend to be the ones we are built on, like C, O, N, etc have an isotope which undergo positron decay. These can be used for imaging, the decay mode produces a 1.022 Mev Positron, which finds an electron within about a mm or so, and produces, via matter-antimatter annihilation, two 511 Kev Photons that exit the body in 180 degree opposed directions. The typical isotope used is f-18, placed on a glucose molecule. This is treated like cold glucose by the body and goes where any glucose would go, mostly to the brain, muscles, and heart. BUT -cancers generally are using a lot of glucose, so this is the basis of PET scanning for cancers. It is fun to tell patients that we are using antimatter to scan them.
There are some other positron emitting isotopes of the physiologic elements, but the half lives are seconds to minutes, making them tough to work with (F-18 is about 2 hours). In the 70's at Sloan Kettering in NY, they installed a pipe under the street from the cyclotron to the nuclear medicine department to immediately deliver 0-15 to the patient (half life 2 minutes), in order to do scans.

@phil - I-131 is primarily a beta emitter. Some alpha emitters are used, like Ra-223 for prostate cancer, but mostly for research purposes.

Hi Ethan

You chose diagrams that illustrate nuclei as tidy arrangements of well defined neutrons and protons, the interior of which seems to be anything but well defined. Do the quarks of individual protons and neutrons remain bound to each other in a special way, or is the whole nucleus a probabilistic Quark Soup like your neutron/proton illustrations? At a quantum mechanical level is this even a meaningful distinction?

Usually, bound states remain bound because their total energy is less than the energy of the free constituents, i.e. the binding energy is negative.

But for quarks inside a proton or neutron, the binding energy is positive! So why do they remain bound? Probably this is due to the fact that free quarks can't exist (confinement).

But how is the binding energy even defined in this case? (It can't be "energy of the bound state minus energy of the state with free particles", because free quarks don't exist.)

Existing as a free quark would require the creation of more energy to create a partner, Bjoern.

It would also have to exit the nucleon and, from the point of view of the binding forces and energy, this is a journey to the moon by shoe leather.

Quick question. For most of the nuclei heavier than boron, it appears that the binding energy per nucleon alternates higher then lower for the next element. For instance, binding energy per nucleon declines going from carbon to nitrogen, rises from nitrogen to oxygen, declines again from oxygen to fluorine, etc. This pattern seems to hold most of the way up to bismuth or so. What is the cause of this?

Helium.

2p2n is a highly bound system. Therefore an even number of p gives you Helium atoms bound in conglomeration and therefore any "spare" protons are not as highly bound as it would be if there were another one to bind with.

@Randy Owens #1: Basically, because neutron radiation doesn't exist "in nature." That is, the radioactive nuclei that you will find by digging up rocks, or by looking at the atmosphere hit by cosmic rays, only decay via beta or alpha emission (with small fractions of channels like electron capture or internal conversion, which produce gammas).

You can get neutron emission in two ways: either you bombard the nucleus with a projectile, such as another nucleus, or gammas; or you start with a nucleus so heavy (heavier than uranium) that it spontaneously fissions. In either case, the result is a couple of smaller nuclei plus one or more neutrons.

I'm confused by the description of gamma radiation. After the emission of a gamma energy photon, the resulting nucleus would have to be lighter, but the description given implies that it is the same element & indeed, isotope (same number of protons & neutrons).

If this is true and the binding energy is the supplier to make the gamma photon, wouldn't this be yet another form of the element beyond the isotope? Should this be an additional number for an element of the periodic table?

Could you pump a nucleus to a higher energy & create a gamma laser?

Obviously, I'm not a physicist, just someone hoping to understand, but what am I missing?

Thanks much.

@Stellar_ash #11: The protons and neutrons in nuclei have "energy levels", just like the electrons in an atom. A nucleus can have a number of "excited states", with the same composition, but with their nucleons in different energy levels.

When such a nucleus "relaxes" or "de-excites" to its ground state, it does so by emitting gamma rays with characteristic energies (just as excited atoms emit visible spectral lines.

Thank you, Doc

Only feared in the wrong hands! How does the science of human nature inform us as to this statement? Now THAT is the quintessential question. Scientists are as prone to human frailties as anyone else, including greed, malice, and psychopathy. Then there's simple mistakes. Scientists have lied for money, and done far worse vis-à-vis cigarette company claims right up to Nazi experiments. Now you say "trust us" again? My answer is a question : how can we?

Ethan
An excellent explanation. I particularly appreciate your clear explanation of proton and neutron mass.

Michael Kelsey
As usual your explanation #9 and #12 are great.

Wow
Thanks for those clear explanations #6 and # 8.

I will have to reread this post and the stream of comments a few more times.

I do have one questions. Taking a look at that Matt Strassler image of the proton and neutron. We see all the quarks and antiquarks; and as well we assume all the various color/anticolor gluons. Now my question is about confinement.

Within a proton or neutron, we certainly have the virtual gluon environment within which glueballs could form. And presumably then those glueballs would be stable enough to be real (rather than virtual particles) and capable of exiting a proton or nucleon. (or NOT, I defer to experts) So can someone give a brief update on the search for glueballs?

I'd just like to know how is the search for glueballs going? And even could glueballs masquerade as something like dark matter? Just asking, maybe even the wrong questions. So, I defer to experts. Thanks.

"I’d just like to know how is the search for glueballs going?"

It's at a sticking point, I think.

Wah wah waaaaaah!

First, to Ethan - what, no love for B+ or EC decay? If you're going to educate the curious, you can't leave out EC! It has the distinguished honor of being the only form of radioactive decay that can, in principle, have its decay rate affected by non-nuclear reactions (take away all the electrons, there is no EC).

Sean @7 - the 30-second answer is that nucleons are more stable when they can pair up. That translates into the even-proton nuclei generally 'holding together' more often when you produce them by slamming two lighter nuclei together. So that saw-blade pattern you see represents slightly higher abundances for the even Z elements, because all their protons are paired up.

While this slightly changes the abundances of the stable elements, it has a far more dramatic effect on the discovery (or production) of new elements. Even wonder why we've discovered 118, 116, 114, but not 117? Its because the even-proton nuclei hold together longer, allowing us to detect them.

Last little tidbit, the same is true for neutrons (nuclei vith even numbers of them tend to be more strongly bound together than nuclei with odd numbers of them).

Michael @9 - yes it does. Uranium and thorium ores emit neutrons 'in nature' as they fission. So does primordial Pu, if you can find any. :)

eric, neutrons contribute to the nuclear force binding over the short range they operate over, and do not contribute to positive electrical potential as protons do in the positively charged nucleus.

Therefore the 2p2n helium nucleus contains the most nuclear binding with the least electric repulsion in the smallest space possible.

Since the electrical force is infinite in range whilst the nuclear force limited, as you get a larger and larger nucleus, the ability of the neutron to add nuclear force binding becomes irrelevant, and only its ability to reduce the electrical density in the neutron remains, hence it becomes slightly better as nuclei get heavier and heavier to put a few neutrons in the mix over and above that needed to create another helium nucleus to spread out the positive charges and reduce the repulsion they feel for each other.

Wow @18 - yes, I know all that. What does it have to do with the fact that nuclei with even numbers of neutrons are generally more stable than 'neighboring' nuclei with odd numbers of neutrons? Your first sentence is basically agreeing whith what I said in my post...all the rest seems to be a different (reasonable and legitimate) point altogether.

" Uranium and thorium ores emit neutrons ‘in nature’"

Only by virtue of moving over to new decay products and finding an embarrassment of riches in the neutron department and wanting to eject the remainder.

The reason why they don't really appear in any definition of radiation is rather like the reason why neutrinos aren't counted in there either: they really don't do much.

The bit the neutron can hit is about 1:10^11 parts of what constitutes even the densest matter we find here on earth.

Therefore they don't really get in on the act.

However, a certain type of uranium when presented with a slow (and hard to find in nature, because nuclear excess energies are generally in the MeV range rather than KeV and less) neutron, that neutron will find it accepted more readily by the nucleus which will then spit out three neutrons that share the excess energy and can be slowed down by enough dense and unreactive material (carbon is a good one: solid at STP and hard to break up, being three helium nuclei hanging about together) to produce neutrons that have a slightly better than 1:1 chance of initiating another reaction with another uranium nucleus of the same type if you've put enough together in a small space.

Which is why you need to refine the stuff a lot to make a useful nuclear reactor.

But the neutrons from most decay products, unlike alpha and beta (and, of course, the photons) do bugger all to anything nearby.

"What does it have to do with the fact that nuclei with even numbers of neutrons are generally more stable than ‘neighboring’ nuclei with odd numbers of neutrons"

It explains it, eric. That's what it has to do with it.

And it explains why it doesn't hold for long in the atomic number.

Your explanation would have 6p0n as a stable atom.

It isn't.

Moreover, the query was about increasing proton, not increasing neutron. Indeed your response was only about the protons, not neutrons.

Quite why you then decided to make it about neutrons instead must be a mistake and you meant protons, hence I treated it as such.

"Mass defect or mass packing fraction" are terms also used to express the difference between bound and unbound particle masses. How can the same thing measured together or separate, give two different masses?
How can the parts of a nucleus, the Proton plus Neutron, be heavier when separated, lighter when together?

Could there be a clue in the standing waves that Tesla detected in his laboratory in 1911?

Standing waves, zero point fields or static fields, all the same thing. They are inertial fields that establish gravitational stability in and of the 4th dimension. Might the binding energy itself not be a factor of universal forces? Using high energy split fields, waste of any sort can be transferred into the 5th dimension, out of our world, into the background of outer space, using the static field.

Whatever the case, It appears that the greatest threat most of us may face is in the form of alpha particles spread. Eating or breathing them in is a problem. Think of breathing a miniature particle sized microwave oven in that keeps running 24/7 from now until eternity. Can we not think of a crop planted in a field, that tries to survive, while the sub atomic micro wave oven is running full time in its roots?

Those close to the overheating reactor, also face gamma and Beta along with Alpha particle issues.

It is understood how to decontaminate alpha particle toxins from our food, but as the ordinary people do not control the issue of our money, nothing is being done to protect us here. Ordinary dust in our air will carry alpha particles into our lungs or rain it on to our food.

How many consider it possible that the Hitachi-GE leaky reactor is a well planned op to contaminate and poison us real well? They refused Russian help from the beginning. Is there some conclusion that we might come to, other than we are in a well staged op to poison us HUGE?

Velocity pumps can decontaminate food and drink, but we don't have them on the shelf as part of our technological world yet. Where is the money for development of static field technology? The issue of money is still held in private hands. What have they done with our purse other than build Nuclear blast and leaky power plants? Must labor not act sensibly and take our purse away from them?

Must labor not STRIKE THEM OUT and get hold of the issue of our paper here? Can we not then hire us some protection from this sparkle waste that is falling out onto our fields and into our air?

Here's a page that shares some theoretical about velocity cures:

http://bitchworld.weebly.com/the-four-elements-of-free-energy.html

@eric #17, Wow #20: Eric, the three natural isotopes of uranium are U-238, U-235, and U-234. The others are short-lived products from either reactors or from alpha absorption on thorium.

You are quite right that neutron radiation occurs in minerals containing U/Th. These come from the interactions both along the decay chain, and from induced reactions (e.g., alpha-n as I mentioned above).

Such neutrons are one of the dominant backgrounds for my own experimental work! I'm a member of the SuperCDMS collaboration, looking for dark matter. Neutrons from the U/Th in the cavern walls, and even worse from U/Th contaminants in the materials of our apparatus, are the main source of false nuclear-recoil signals in our detectors.

@Wow #18, #21, #22: Eric was more correct than you are on this issue. Nuclear stability is driven by Pauli pairing of the protons, and of the neutrons, _independently_. Even-even nuclei have maximal binding energy compared with their neighbors (with 4-He being the extreme example). Even-odd and odd-even nuclei have slightly lower binding energies (and hence tend to decay to an even-even neighbor), while odd-odd nuclei are the "least stable" in this sense.

Your argument for "alpha clusters" in nuclei is an over-simplification. While a useful mnemonic, it is really only useful as such for lighter nuclei (say, nickel and below).

Heavy nuclei always have a neutron excess, because the strong binding from the neutrons is required to overcome the Coulomb repulsion of the protons. Your silly straw man example of a 6-proton cluster is an obvious instance of that, and is often a homework problem in nuclear theory.

No, Mike.

He missed out a hell of a lot.

And this:

"Heavy nuclei always have a neutron excess, because the strong binding from the neutrons is required to overcome the Coulomb repulsion of the protons."

is wrong.

Nuclear force range is...?

Moreover you appear to be including a shitload in eric's post that wasn't there.

Go read it again for what IS there, don't go including things you know "ought" to be there because you already know how nucleons bind in a nucleus.

[Me] What does it have to do with the fact that nuclei with even numbers of neutrons are generally more stable than ‘neighboring’ nuclei with odd numbers of neutrons”

[Wow] It explains it, eric. That’s what it has to do with it.

No, you are confused. Reread my post. I was not telling Sean that p number = n number is inherently more stable, I was discussing the fact that nuclei with even numbers of neutrons (2, 4, 6, 8...) tend to me more tightly bound than nuclei with odd numbers of neutrons (1,3,5,7...). Though odd-odd nuclei can be more stable than either even-odd or odd-even.

What you are talking about - neutron mitigation of charge repulsion - is responsible for the overall slope less than 1 seen in chart of nuclides (the figure with "image credit: I Cullen" under it). But Sean wasn't asking about that chart. He was asking about figure 1.1. And nucleon pair formation is responsible for the alternation that Sean T sees in figure 1.1.

And it explains why it doesn’t hold for long in the atomic number.

Again, you seem to think I said something I did not say. I was not referring to the ratio of protons to neutrons.

What I actually did say ("nuclei vith [sic] even numbers of them [neutrons] tend to be more strongly bound together than nuclei with odd numbers of them") does hold, in fact, generally across the entire chart of the nuclides.

Quite why you then decided to make it about neutrons instead must be a mistake and you meant protons, hence I treated it as such.

No, it wasn't a mistake. An aside, yes, but not a mistake. If you look at the chart of nuclides and read across the boxes in a given line (i.e. at the isotopes of a single element),* you will see an alternation in stability. That alternation is caused by neutrons pairing with another nucleon.

*And for goodness' sake, go higher than carbon. You know as well as I that the effect I'm talking about doesn't kick in until about Z = 16.

Michael, here's illustration of why you're wrong on the neutron thing:

Why isn't it Cobalt-54 that is stable?

* No, you are confused.

No I'm not.

* Reread my post.

I did. I read what you wrote, not what you meant when you wrote it.

* I was not telling Sean that p number = n number is inherently more stable

Ah, well, you're confused. Reread my post.

I did not claim you were saying that. Go reread your post after reading mine again and see where you made your mistake.

* I was discussing the fact that nuclei with even numbers of neutrons (2, 4, 6, 8…) tend to me more tightly bound than nuclei with odd numbers of neutrons (1,3,5,7…).

Go re read Sean's post. Here's an excerpt:

"binding energy per nucleon declines going from carbon to nitrogen, rises from nitrogen to oxygen, declines again from oxygen to fluorine, etc."

Notice that the change here is by protons. That's how you change from one element to another.

The reason for this is Helium.

2p2n is helium. Highly bound. 3p3n is helium plus deuterium, 4p4n is two helium.

This goes up for a bit then you need more neutrons and eventually the binding per nucleon is lower because to get a stable isotope you need more than just two nucleons to go up to the next element, but three. Then you need four.

* I was not referring to the ratio of protons to neutrons

I know.

Which is why I said you were incomplete in your explanation and that this incompleteness is what MY response had to do with it.

Did you even read what you asked?

* No, it wasn’t a mistake. An aside, yes, but not a mistake.

OK, then you refuted your own claims about protons because you then segued into neutrons in a question about protons.

You know, that element change thing again. Needs protons. Or it isn't another element, it's an isotope.

And yes, it takes a few protons before the effect kicks in.

The effect, however, kicks in.

Ignoring it doesn't mean it doesn't exist, dear.

@Wow #29: "Why isn’t it Cobalt-54 that is stable?" I am so glad you chose that example, because it exactly illustrates my point (and why you are mistaken about this issue).

54-Co has 27 protons and 27 neutrons. It is an odd-odd nucleus, and what's more, does not have enough neutrons to overcome the Z=27 Coulomb repulsion. Therefore, it is not stable.

The _stable_ isotope is 59-Co, which has 27 protons (duh) and _32_ neutrons. Notice two things; first, the stable nucleus has an _even_ number of neutrons, meaning all filled Pauli pairs, and second, there are five "extra" neutrons compared with the light nuclei Z=N pattern. Those extra neutrons are just enough to push the nuclear binding (i.e., the Yukawa exchange of pions) above the Coulomb repulsion. As Z increases further, the neutron excess has to get larger and larger (for 238-U, for example, Z=92 but N=146).

@Wow #28: You wrote, "
[quoting me: ]“Heavy nuclei always have a neutron excess, because the strong binding from the neutrons is required to overcome the Coulomb repulsion of the protons.” [end quoting me]
is wrong.

Nuclear force range is…?"

1) My statement is not wrong. Please take a look at the chart of nuclides, and note the slope of the Z vs. N axis. You will see that that slope is significantly less than 1, because N > Z for stable nuclei much beyond iron (i.e., _heavy_ nuclei).

2) The binding force between nucleons is nuclei is very well described by an effective Yukawa potential (exp(-l/L)) driven by the exchange of virtual pions (and other light mesons). The characteristic range of this potential (L) is several femtometers, or about the diameter of a litium or beryllium nucleus.

* I am so glad you chose that example, because it exactly illustrates my point (and why you are mistaken about this issue).

And here's your problem: you're thinking that this demonstrates I have a problem.

You would have thought someone would think it through, but hey, no, not you, eh?

Notice how the number of neutrons being 27 aren't enough to make it stable. Therefore your assertion

"Heavy nuclei always have a neutron excess, because the strong binding from the neutrons is required to overcome the Coulomb repulsion of the protons.”

is wrong.

I know what you *mean* but that isn't what you're *saying*.

You see if your assertion there were, as written, correct, then the 1 proton and 1 neutron would bind nicely because *according to the statement made* the "strong binding overcomes the coulomb force.

Two neutrons don't bind to a proton to make a stable Tritium. As an example.

Two neutrons will bind together and do so to exclude a proton coming in, but they do not interact in the coulomb force interaction themselves.

They are filler.

They space out the other constituents that ARE charged (2p2n) and reduce the energy needed to keep all those doubly-charged 2p2n as far away as possible given the strong force would like to make them all meet as closely packed as possible.

The increasing number required as you get bigger and bigger are because the nuclear force is short-ranged, being passed about by a massive particle, whereas the electric force of the positive charges are carried by massless particles, hence are unlimited in range.

Like I say, I know what you *mean*, but you're remembering everything you know but cannot and/or did not fit in to your posts.

And without that, your posts have been incorrect.

"1) My statement is not wrong"

Yes it is. Hopefully you can see why now.

"The characteristic range of this potential (L) is several femtometers, or about the diameter of a litium or beryllium nucleus."

Therefore a neutron that can only "bind" on that range cannot affect a nucleus bigger than that.

Hence your assertion re the neutrons cannot be true except in the trivial case of "when the nucleus is no bigger than that".

Which is rather eric's "point" that the effect doesn't begin to matter until around atomic number 16.

As an example, why does Co54 decay to Chromium?

(note, I assume it would be the next decay product, based solely on the heaviest element that has 54 nucleons, though I had guessed it would be somewhere around atomic number 21, but was off by a couple)

Because neutrons would like to decay to protons.

Therefore the balancing act becomes: does the gain in electric potential if I were a proton instead exceed the energy I'd release if I relaxed to a proton?

Note too: Cr53 is stable. A neutron sitting about all on its lonesome.

Your statements are "true" if you know what you're missing out here, Michael. You do. But someone reading this won't.

But they're only true for some elements and your statement is only *true* true knowing how to work out where your assertion holds and where it doesn't.

And absent that information, it makes your *actual statements* false, because they only contain the context of the information supplied.

My statements are more true within the context of the information supplied, even though it doesn't make a claim on any specific occurrence, just explains the factors. Where it doesn't apply, it's *truly* false.

And unreliable, especially where its not necessary, is worse than wrong when it comes to teaching or informing people. Your statement re: double neutrons (remember, Sean said *nucleons*, not neutrinos) is wrong with Cr53.

Your assertion is wrong because it's a "there are no black swan" assertion.

I made no assertions of the precise colour, just that colours exist. To stretch the metaphor.

Concerning Arafat ,there is no question that he was poisoned by enemies with Polonium and Israel had them available.

Wow,
Michael addressed or is addressing most of your points better than I can, so I'm going to keep this short.

As an example, why does Co54 decay to Chromium?

It doesn't. It ECs to Fe54, which has an even number of both protons and neutrons. So this is now the second instance of you providing quite a nice example of what Michael and I are talking about.

Note too: Cr53 is stable. A neutron sitting about all on its lonesome.

Yeah, it's a shame Co54 doesn't decay into Cr53, or you might have a valid point.

In fact Chromium is yet another good example of what we're talking about . The stable isotopes are 50 (even even), 52, (even even), 53, (even odd), and 54 (even even). Notably, 51 is not stable despite the fact that both the immediately lighter and immediately heavier isotopes around it are. This is exactly what I was talking about in my first post, when i mentioned neutron pairing. Cr50 vs. Cr51 is a classic example of how neutron pairing can be more important than the simple charge mitigation effect you're talking about. If it was all about reducing the impact of proton charge on proton charge, then 51 should be more stable than 50. But it isn't - its less stable. Why? Because in 50 all the neutrons pair up, while in 51, they can't.

@Wow various: Let's start with some very simple statements.

1) Forces add linearly.

2) The nuclear potential is the sum of the inter-nucleon potentials (where the sum is really an integral taking account of the distances involved).

Statement (1) means that a comment like "the nuclear binding exceeds the Coulomb repulsion)" is a statement about relative magnitudes, which add to determine the net force (potential) involved.

Statement (2) means that the few-fm range of the individual nucleon-nucleon forces still adds up to determine the net nuclear potential. That integral inlcludes both the exp(-l/L) attractive Yukawa coupling, *and* the 1/l^2 replusion between protons (obviously n-n and n-p pairs don't have a Coulomb term).

I leave it as a homework exercise to perform the necessary sum over all nucleon-nucleon pairs, and the integral over distances, to derive the net nuclear potential.

Once you've done that, please come back and explain, in detail, where my statements were incorrect. If you can't do so, please review the appropriate literature, including first-year graduate textbooks on nuclear physics, to find the well-known form for the averaged nuclear potential as a function of radius.

One last goof of Wow's that I want to address.

As an example, why does Co54 decay to Chromium?
...
Because neutrons would like to decay to protons.

In fact, the decay of Co54 involves a proton 'capturing' an s-electron and converting into a neutron.

So not only did you get the product element wrong, you got the nuclear reaction that's occurring backwards.

"Michael addressed or is addressing most of your points better than I can, so I’m going to keep this short. "

He;'s responding to them, but only some of them.

For example, he's continually ignoring as you were what Sean was asking.

Nucleons are not neutrons.

" As an example, why does Co54 decay to Chromium?

It doesn’t."

And here yet again is why you're an ass, along with Mike here.

Did you spot this bit before you gleefully jumped to go "HE'S WRONG, EVERYBODY! LOOK HE'S WRONG HERE!!!!"

No, you did not.

Just like you STILL don't understand that it was nucleons said, not neutrons. And the example given was a change of proton, not neutrons.

Why?

Because you've staked your self perception, like Mike has, on not being wrong in any factor, form or title.

So you, like Mike, refuse to actually read things if that doesn't generate your needed story.

"@Wow various: Let’s start with some very simple statements.

1) Forces add linearly."

Lets start with point #1 being wrong.

Shit, this is like the prof at university who, seeing two undergrads whistling to see who can get the sharpest peak in the FFT oscilloscope then disdainfully said "Do you think you can get your larynx out to measure it to see how to calculate that frequency?" then regally stalked away.

So lets start with point 1.

It's wrong.

For quite a few reasons, but the most pertinent one is that one force here is infinite in range and the other one limited, therefore the forces do not add because one doesn't get to the entire nucleus.

@Wow #42: In your example, the professor was quite wrong: the undergrads can do the experiment, and use the result to _calculate_ the characteristic dimensions of their vocal apparatus.

In your case you are missing some basic physics. Forces add linearly. Period. If you have a force where the potential has a limited range (like the Yukawa potential V = exp(-r/R)), that just means that in the sum outside that region it contributes zero. The equations are still linear. Period.

For the case of a nuclear potential, the form is a sum of powers of 1/r. For large r, it's primarily a -1/r repulsion (which gives the expected 1/r^2 force). Close to, and inside the nucleus, it's an attractive potential which goes, I think, something like 1/r^4, and then there is a repulsive core like 1/r^7. When you add them all up, the potential has a minimum at some characteristic radius.

As I did before, I encourage you to look up the fine details in a either an upper division undergraduate, or first-year graduate, textbook. You might even choose to read the Wikipedia article (https://en.wikipedia.org/wiki/Nuclear_potential), which repeats what I've written in previous posts, but with better numbers. Or, you can continue to assert your own infallibility.

@Wow #41: Unfortunately, you're the one who fails to understand what Sean #7 was asking. He used the exact phrase "binding energy per nucleon" twice in his question, because that is the exact phrase used to label the Y axis on the plot in question. Perhaps you're so caught up in your own infallibility that you couldn't see the forest for your trees.

He was asking about the alternation in AVERAGE BINDING ENERGY PER NUCLEON as a function of ATOMIC NUMBER (Z), that is, the number of protons.

That _average_ is computed for all of the isotopes of a given element, and so washes out the detailed dependence on N (which also has the same even-odd cycling), which is more visible in the two-dimensional chart of nuclides.

Having averaged away the neutron dependence, the remaining even-odd dependence on Z is exactly what Eric and I explained, that nucleons (being fermions, just like electrons) form pairs with lower total energy than two separated nucleons.

* He used the exact phrase “binding energy per nucleon” twice in his question, because that is the exact phrase used to label the Y axis on the plot in question.

No, I know that.

Nucleon != Neutron.

* He was asking about the alternation in AVERAGE BINDING ENERGY PER NUCLEON as a function of ATOMIC NUMBER (Z), that is, the number of protons.

I know.

Proton != Neutron.

* That _average_ is computed for all of the isotopes of a given element

I know.

* Having averaged away the neutron dependence

Why then keep banging on about neutrons then?

* the remaining even-odd dependence on Z is exactly what Eric and I explained

No, because, as you said earlier in that post:

"ATOMIC NUMBER (Z), that is, the number of protons. "

Yet you kept banging on about neutrons.

"@Wow #42: In your example, the professor was quite wrong: the undergrads can do the experiment, and use the result to _calculate_ the characteristic dimensions of their vocal apparatus."

He was a shitload more wrong than that, kid.

You don' t use your vocal chords to whistle with.

* In your case you are missing some basic physics. Forces add linearly. Period.

You're wrong. PERIOD.

A force that doesn't go that far doesn't add at all.

You are adding zero.

The force doesn't go there, so it adds zero. Which means it isn't adding at all.

@Wow: I don't need the abuse you enjoy heaping out to the other readers of this blog. You don't listen, you can't read, and you don't seem to understand the basic physics you so abusively deride others for.

I have tried to correct your misunderstanding clearly and directly, while still being polite. You have not. Any further abusive language on your part will lead to a request that you be banned from these fora.

Mike, that abuse is a figment of your wounded pride, dear.

Did I call your fatuous bollocks about how I don't understand something merely because you'd like to talk down to me as if I'm some pre-schooler, abuse?

Fuck no.

Why?

Because I'm actually an adult.

Not a moronic little toerag who isn't listening to a damn thing in case they hear something that doesn't get their ego stroked.

I've tried to show you where you're wrong, but you've 100% ignored it and instead given baby talk in a pretense to belittle me.

Then you have the unmitigated gall to whine about "abuse" and fellate yourself on how "polite" you've been because you're not used words you've decided are not polite.

Polite isn't just not using "fuck off", you braindead moron.

It's actually listening to someone when they say something.

Wow
Here's the thing Wow.
You are abusive. And it gets very tiring.

The thing is, I can't imagine that in person you talk with people the way you do out here on this blog. Because in person, someone a lot less polite than Michael Kelsey would punch your teeth in.

So I assume that out here you take on a different persona.

Whereas out here, I assume that Michael Kelsey, or Ethan have the same persona as they do in daily life.

So I would suggest that out here on this blog; that you try to give people the same kind of attitude that you do in your day to day life.

Now if you say that you carry the same attitude in your daily life with the grocer, the taxi driver, the street preacher and so; then tell me, Do you still have all of your teeth?

Personally, Wow, I am not for banning you from this blog.
1) I think you do understand and contribute to the science discssion.
2) You do fight the antiscienc folks tit for tat
3) Your venom and rudeness has diminished over the years (We all grow).

Psychologically, having an integrated personality, is not the norm. It is rather unusual. The various masks and attitudes that people have and carry change like the weather; and it is the rare person with the personal integrity to objectively observe and be self critical of their various unintegrated persona, masks and attitudes.

Of course some scientific folks think that psychology is nonsense and not science. They are wrong. The first requirement of a scientist is to be objective and this is not possible if they are not able to look themselves in the eye and acknowledge their biases and limitations; personal as well as professional.

You see, my guess is that in your personal life, that you Wow are a bit of a mouse. And you need to better integrate online persona and your day-to-day life persona; to the benefit of both. Yes, bring more appropriate anger to your day to day life; and you will be surprised that much of your inappropriate blog anger will fade.

Wow

Try appropriately expressing some of your online blog anger in your offline day to day life.

I suspect that you are a bit more civil in your day to day life (or else I suspect you are missing a few teeth).

Now if you can learn to appropriately express your anger in the flesh; then I predict that online on this blog, you will find that your need to be inappropriately angry and rude will disappear.

Yes, yes; this advice is coming from someone who has spent a lot of years in psychotherapy. I told you once before Wow, during an online argument that I do not know anyone who is more angry than I. Mostly, it comes out appropriately now. It's taken a lot of years of emotional work.

Wow, I do not think that you should not be banned from this blog. What I do believe is that if you were in a coffee shop talking to Michael Kelsey; that you would be quite civil and not a bit rude. And I suggest that you can learn to bring your day to day civil behavior to this blog. It is possible to disagree and stand correct and yet be assertive. there is really very little reason to be rude. Being rude is evidence that we are helpless and insecure and need to work on that. I also suspect that in coffee shop that you would be inappropriately silent and you need to be more assertive in the flesh.

Yes, yes, Wow, I expect you to pummel me for these remarks.
Fine but think upon what I say.
Don't delude yourself and pretend that there is no truth in what I or Michael Kelsey say.

F me, I started reading this thread thinking 'Wow has really calmed his ass down over the last few months, can be really quite helpful nowadays' and BOOM. Mr Hyde returns.

Seriously dude - read all that back and imagine you didn't write it. See how it looks.

"Because I’m actually an adult... Not a moronic little toerag... Polite isn’t just not using “fuck off”, you braindead moron."

Can you for one second picture that exchange in a face-to-face discussion not ending in blows?

This isn't the comments for an Alex Jones Youtube video. Nor is it a pissing contest where 'one side must win'. You can always agree to disagree, too. Or disagree on semantics, if not the physics.

I've no idea which of you is correct and I don't care. Hiding behind anonymity is allowing you to stoop to levels you would never do in real life (I hope).

Take a breath, calm down. Just no need for that.

Fuck off, mcandrew.

Instead of looking to see how I'm wrong, how about just fucking reading the stuff, eh?

eric gives an explanation that only holds for a short while and I explain to eric why it's not right to say so, he then goes "What does that have to do with it?" Well, what it has to do with it is "It's telling you where you're wrong".

However, this is ignored as it doesn't gel with the self image eric has of either himself or me.

So he then starts wibbling on about neutrons when the query was about nucleons and the EVEN COUNT of protons.

So I point it out and then eric and Michael jump in with a whole load of wrong shit, ignoring EVERYTHING said in a base attempt to shout down someone who uses ruder words than they like people to use.

Then YOU come along and go all concern trolling and waving your flaccid e-peen all over the place to show how brilliant you are.

Well fuck off.

Read the shit before you jump to a conclusion, moron.

"Try appropriately expressing some of your online blog anger in your offline day to day life."

I do.

Try not pushing a derogatory and demeaning attitude and life onto other people you know FUCK ALL about.

Trying that shit in real life will lead you to be wearing your arsehole around your shoulders, your arse will be that kicked.

"I suspect that you are a bit more civil in your day to day life (or else I suspect you are missing a few teeth)."

Based on your presupposition that you only entered into because you want to find fault.

No, I do this IRL too.

Do you know why I get away with it?

Not because I'm 6'8 and 280lb.

No.

Because I'm as hard on my as anyone else.

@wow#46 A force that doesn’t go that far doesn’t add at all.

You are adding zero.

The force doesn’t go there, so it adds zero. Which means it isn’t adding at all.

You seem to be resorting to semantics to win your argument. The term certainly does not contribute to the result, but to a mathematician it is still "added" even if it evaluates to zero.

But my understanding of the above discussion is that it is never zero anyway, it is merely asymptotic to zero. So the forces are additive whatever the distance, and you seem to be contesting Michael's statement of fact by extrapolating from your approximation.

"You seem to be resorting to semantics"

Indeed.

Just like Michael and not, unfortunately, eric, OKThen, MacAndrews.

But somehow you only noted one. Odd how that goes, eh?

If the force carrier goes no further than a femtometer, then something two femptometers DOES NOT ADD TO THE FORCES.

Michael is only correct in so far as that addition is zero.

But apparently pointing it out is "merely semantics" FOR THE WRONG PERSON.

"But my understanding of the above discussion is that it is never zero anyway, it is merely asymptotic to zero."

No, the force carriers are massive. They have rest mass. Therefore their ability to survive has a limited lifespan: even if they carry no energy to impart in the force exchange, they cannot last longer than the uncertainty principle allows. The faster they go, the more energy they can impart but the shorter they can last.

"So the forces are additive whatever the distance"

You DO NOT ADD a force that cannot act.

"they cannot last longer than the uncertainty principle allows"

Whatever others have posted, you seem to be the one arguing from the assertion that "zero" and "too small to matter" are exact equivalents.

It's 35 years since I did my physics degree, so things might have changed since then. In those days the uncertainty principle applied to the result of the product of two variables. Hence if one variable is zero the other must be infinite. You state:

"If the force carrier goes no further than a femtometer, then something two femptometers DOES NOT ADD TO THE FORCES."

Clearly as a conditional statement it is undeniably logically correct., whereas the statement below must become unconditional as our definition of "small" tends to zero.:

Since the force carrier is very unlikely to go more than a femtometer, then the added effect on something at two femptometers is so small it can be ignored.

Can you agree with that statement?

* Whatever others have posted, you seem to be the one arguing from the assertion that “zero” and “too small to matter” are exact equivalents.

They aren't here.

If you do work for me and I pay you nothing, then your payment is zero.

If you don't do anything for me to pay, then your payment is zero.

The two are not equivalent things, though.

Are they.

* In those days the uncertainty principle applied to the result of the product of two variables. Hence if one variable is zero the other must be infinite.

Indeed it is.

However, despite knowing this, you're not seemingly capable of applying it other than in the abstract.

You see the thing is that the force carrier for the weak and strong nuclear forces are not zero mass.

Therefore there's not a zero.

Therefore there's not an infinity.

YOUR assertion only, and I repeat ONLY applies to force carriers that have zero rest mass.

Well Wow, we seem to agree on everything except the final conclusion, so I am clearly missing something. Please can you explain what the exact relationship between magnitude and distance for the force we are discussing is, particularly at exactly what distance does it reach zero?

Mass-energy of a particle: m0.c^2.

Uncertainty principle: E.t<= hbar

Ergo:

t<=hbar/m0.c^2

Therefore if m0 (rest mass) not zero, t cannot be bigger than a set value, and in that case, it cannot have any kinetic energy. If it has no kinetic energy, then the maximum distance the particle will travel is zero.

s=ut

and when u=0, s=0.

If the particle has as much kinetic energy as it has rest mass, it can only last half as long. But at least then it goes a distance.

But the higher m0, the shorter time it can last before it has to poof out or violate conservation of energy.

The distance at which it can no longer exist reduces the heavier the rest mass of the particle involved in the intermediation is.

To the limit of infinity if m0 is zero.

Try here:

http://www.phy.duke.edu/~kolena/modern/forces.html

At least they can use proper symbols.

Here's Sean's observation:

--- it appears that the binding energy per nucleon alternates higher then lower for the next element. ---

Changing neutrons do not change the elements.

Well I did learn something from that exercise, so it was not a complete waste of time. Can I distil the essence of what you are saying to:

"The maximum range of a force is inversely proportional to the rest mass of the associated force carrier"?

But this does not invalidate the statement that "forces add linearly", which you took strong exception too. The equation for total force felt by a particle is the sum of the individual forces acting on it. Not only is this still true when one of the terms evaluates to zero, but surely to a scientist it is the experimentally observed or theoretically deduced value of that term that sets an upper limit on the value of the rest mass of the force carrier.

“The maximum range of a force is inversely proportional to the rest mass of the associated force carrier”

Aye, that's about right.

"But this does not invalidate the statement that “forces add linearly”"

It does.

For the same reason as "You haven't paid me a penny!" changes depending on whether you did anything that needed paying from me.

Hell, I even spent very many words elucidating that although it was "right" technically, since a force that doesn't exist adds zero to the result, BUT YOU DO NOT DO THE SUM OF ADDING ZERO.

And it's that capitalised bit that is really quite important.

The addition of forces that make a photon fly through the vacuum doesn't include the electrical potential force of the charged atom near the sun.

NOT because the force is "practically zero" but because it doesn't interact via that force.

The forces making you move around DO NOT include a zero force component from my pushing you BECAUSE I AM NOT PUSHING YOU.

PS glad to hear you learnt something.

When I was introduced to virtual particles at Uni, the concordance there how the *explanation* for the range of the forces fall out from the uncertainty principle that allows for virtual particles was particularly harmonious to me.

@52:

eric gives an explanation that only holds for a short while

The pairing effect holds all the time. For both neutrons and protons. And it holds across most of the chart of nuclides; I eyeball it as occurring between Z=18 and Z=108. On the lower end, its overwhelmed by coulomb effects like the one you mentioned. On the higher end, we are looking at single or few-atom detections; such a pattern may simply be lost.

Now I'll try once again, although I'm basically just repeating what I wrote the first time: the effect Sean asked about is due to proton pairing. As a last little tidbit for Sean and other laymen, they might like to know that neutrons pair in a similar manner. This neutron pairing is not directly responsible for the effect seen in Fig 1.1, but it is responsible for the pattern of alternating less-and-more stable isotopes which is seen for most elements throughout the chart of nuclides (like the Cullen figure), from approximately Z=18 on up. It is responsible (to use your choice of example, Chromium) for the fact that 50Cr and 52Cr are both stable but 51Cr is not. It is also responsible for the fact that 48Cr has a half-life thirty times longer than 49Cr.

""eric gives an explanation that only holds for a short while "

The pairing effect holds all the time"

Well given even you said:

"*And for goodness’ sake, go higher than carbon. You know as well as I that the effect I’m talking about doesn’t kick in until about Z = 16."

I wonder why you claim differently.

"Now I’ll try once again, although I’m basically just repeating what I wrote the first time: the effect Sean asked about is due to proton pairing."

No, you nitwit.

Pairing off isn't going to cut it. If that were all of it, then 6p would be stable.

It isn't.

The effect is that 2p2n is very very stable and every even proton number can form one or more Helium nuclei, each of which are very highly bound, therefore the binding per nucleon is a local maxima.

The heavier nuclei require more neutrons to thin out the protons because of the electrical force they suffer under that neutrons don't, whilst both are affected by nuclear binding.

And I draw your myopic view again to this statement:

"proton pairing."

Flip flop flip flop flip flop.

You spent a lot of time squarking about neutrons.

Now you're back on protons again.

Do you have any idea what you're saying, or is it just being made up as you go along, hence all these logical errors you blurt out?

[me]The pairing effect holds all the time”

[Wow]Well given even you said:

“*And for goodness’ sake, go higher than carbon. You know as well as I that the effect I’m talking about doesn’t kick in until about Z = 16.”

Yes, it holds all the time. Are you now measuring time in amu? Charge units? In some nuclei, other forces overwhelm the effect, but it is still there. Thus your 6p example is just silly. I've never said its the only force; I'm saying its a force and that it explains the sawblade pattern seen in figure 1.1.

The reason your "contains 2p2n" reasoning is wrong is that many of the higher Z nuclei in figure 1.1 do not contain the same numer of protons and neutrons. Thus, they are not solely composed of 2p2n units. But they still show the pattern. Why? Because 2p2n is a derivative effect of a more general rule, and that's the pairing rule. YOUR explanation is good for a few of the lower Z elements but explains nothing else; the pairing explains all of them

“proton pairing.”

Flip flop flip flop flip flop.

You spent a lot of time squarking about neutrons.

Now you’re back on protons again.

Do you have any idea what you’re saying, or is it just being made up as you go along, hence all these logical errors you blurt out?

I think here you are transparently misrepresenting me. I've very clearly been making two points the entire time, not flip flopping.

I invite anyone to read my second paragraph in @65 and draw your own conclusions about whether I'm flip flopping, as Wow says, or making two points - one about protons, another about neutrons.

Because I think you're now being deceptive, this will be my last post on this thread. Feel free to get in the last word.

eric, if the follow up question were "So why is Helium so tightly bound, then?" your response "pairing" would be in there.

However, "pairing" in answer to the query Sean had is about as accurate and useful as answering "Nuclear forces".

I.e. so pointless an answer it's wrong.

But no, you've heard "pairing" somewhere and you're damn well going to bleat it again and again because you've heard it and it sounds like an answer to you.

And eric, you've not been reading your own posts if you're going to edit them to mean what you've put there.

You may be writing out what you *meant* to say, but that's only what you put in your head. Not what you put into type.

> [me]The pairing effect holds all the time”
>
> [Wow]Well given even you said:
>
> “*And for goodness’ sake, go higher than carbon. You know as well as I that the effect I’m talking about doesn’t kick in until about Z = 16.”

> Yes, it holds all the time.

Ah, I see.

"What's the time?"

"Elephant!"

Which may be the answer to a different question, but it's not the question put or answered.

No you didn't.

You read what you thought should be there.

The binding energy of the deuteron is simple to calculate. Just apply electric and magnetic Coulomb forces statically, without the assumption of nucleons orbiting around nothing.

All details in my paper
http://www.aemjournal.org/index.php/AEM/article/view/218/

Why did the Universe start off with Hydrogen, Helium, and not much else?

esiegel — Fri, 05 Jul 2013 13:11:45 +0000

Why did the Universe start off with Hydrogen, Helium, and not much else?

"I see a lot of new faces. But, you know the old saying, 'out with the old, in with the nucleus.'" -The Simpsons

Looking around the Universe today, there's no doubt that there's plenty of hydrogen and helium around; after all, it's the nuclear fusion of hydrogen into helium that powers the vast majority of stars illuminating the entire cosmos!

Image credit: ESA/Hubble, NASA and H. Ebeling.

But here on Earth, hydrogen and helium are only a small part of the world we inhabit. By mass, hydrogen and helium combined make up far less than 1% of the Earth, and even if we restrict ourselves to the Earth's crust, it's still just a tiny percentage compared to the other, heavier elements.

Image credit: Gordon B. Haxel, Sara Boore, and Susan Mayfield from USGS / Wikimedia user michbich.

Practically all of these heavy elements were formed in generations of stars: stars that lived, burned their fuel into heavier elements, died and shed their heavy, enriched elements back into the cosmos, and were incorporated into the next generations of stars and -- when the heavier elements became abundant enough -- rocky planets.

Image credit: NASA / Lynette Cook.

But the Universe didn't start off with these heavier elements at all. In fact, if you'll remember what the Big Bang says, the Universe is expanding (and cooling) now, meaning that all the matter in it was closer together -- and the radiation in it was hotter -- in the past. If you go back to a sufficiently early time, you'll find that the density was high enough and the temperature was hot enough that you couldn't even form neutral atoms without them immediately being blasted apart! When the Universe cooled through that phase, that's when neutral atoms formed for the first time, and where the cosmic microwave background comes from.

Image credit: Pearson / Addison Wesley, retrieved from Jill Bechtold.

At that time, the Universe was made out of about 92% hydrogen atoms and 8% helium atoms by number (or about 75-76% hydrogen and 24-25% helium by mass), with trace amounts of lithium and beryllium, but not much else. But you might wonder how it got to have exactly that ratio? After all, it didn't have to be that way; if the Universe was hot and dense enough to undergo nuclear fusion early on, why did it only fuse atoms up to helium, and why didn't more of the Universe become helium than it did?

To find the answer, we need to go way back in time. Not just to the first few hundred thousand years of the Universe, when it was making the first atoms, nor even to the first years, days, or hours. No, we need to go back to when the temperatures were so high, when the Universe was so hot, that not only could atomic nuclei not form (for they'd be immediately be blasted apart), but to a time when the Universe was so hot that the Universe was filled with nearly equal amount of matter-and-antimatter, when it was just a fraction of a second old!

Image credit: James Schombert of the University of Oregon.

It was once so hot that the Universe was filled with nearly equal amount of matter and antimatter: protons and antiprotons, neutrons and antineutrons, electrons and positrons, neutrinos and antineutrinos, and of course photons (which are their own antiparticle), among others. (They're not exactly equal; see here for more on that.) When the Universe is hot -- and by hot, I mean above the temperature needed to spontaneously create a matter/antimatter pair from two typical photons -- you get huge amounts of that form of matter and antimatter. They get spontaneously created from photons just as quickly as they find one another and annihilate back into photons. But as the Universe cools, those matter/antimatter pairs begin to annihilate faster, and it becomes more difficult to find photons energetic enough to make them. Eventually, it cools enough that all the exotic particles go away, and all the antiprotons and antineutrons annihilate with protons and neutrons, leaving only a small asymmetry of matter (in the form of protons and neutrons) over antimatter, bathed in a sea of radiation.

Image credit: me, background by Christoph Schaefer.

At this point, when the Universe is a fraction of a second old, there are roughly equal amounts of protons and neutrons: about a 50/50 split. These protons and neutrons will eventually become the atoms in our Universe, but they've got a lot to go through first. On the other hand, electrons (and positrons) are much lighter, so they still exist in huge numbers (and at great energies) for a while longer.

Image credit: Addison-Wesley, retrieved from J. Imamura / U. of Oregon.

It's still hot enough that protons and neutrons can convert into one another very easily: a proton can combine with an electron to make a neutron and (an electron) neutrino, while a neutron can combine with (an electron) neutrino to make a proton and an electron. While there aren't that many protons and neutrons in the Universe at this time, electrons and neutrinos outnumber them by around a billion-to-one. This is why, early on, there's about a 50/50 split of protons and neutrons.

Neutrons, as you'll remember, are slightly heavier than protons: by about 0.2%. As the Universe cools (and the excess positrons annihilate away), it becomes rarer and rarer to find a proton-electron pair with enough energy to create a neutron, while it's still relatively easy for a neutron-neutrino pair to create a proton-electron pair. This converts a substantial fraction of neutrons into protons during the first one-to-three seconds of the Universe. By time these interactions have become insignificant, the proton-to-neutron ratio has changed from about 50/50 to 85/15!

Image credit: Smith, Christel J. et al. Phys.Rev. D81 (2010) 065027.

Now, these protons and neutrons are abundant, hot, and dense enough that they can fuse together into heavier elements, and believe me, they'd love to. But photons -- particles of radiation -- outnumber protons-and-neutrons by more than a billion to one, so for minutes of the Universe expanding and cooling, it's still energetic enough that every time a proton and neutron fuse together to form deuterium, the first stepping-stone in nuclear fusion, a high-enough energy photon immediately comes along and blasts them apart! This is known as the deuterium bottleneck, as deuterium is relatively fragile, and its fragility prevents further nuclear reactions from occurring.

Image credit: me, modified from Lawrence Berkeley Labs.

In the meantime, while the minutes tick by, something else is going on. A free proton is stable, so nothing happens to them, but a free neutron is unstable; it will decay into a proton, electron, and an (electron) antineutrino with a half-life of about ten minutes. By time the Universe has cooled enough that the created deuterium wouldn't be immediately be blasted back apart, more than three minutes have gone by, further changing the 85%-proton/15%-neutron split to nearly 88% protons and just a hair over 12% neutrons.

Image credit: Ronaldo E. de Souza.

Finally, with deuterium forming, nuclear fusion can proceed, and it proceeds extremely rapidly! Through a couple of different fusion chains, the Universe is still hot and dense enough that pretty much every neutron around wind up combining with one other neutron and two protons to form helium-4, an isotope of helium that's much more energetically stable than deuterium, tritium, or helium-3!

Images taken from LBL, stitched together by me.

By time this happens, though, the Universe is nearly four minutes old, and is far too diffuse and cold to undergo the next major step of fusion that happens in stars, which is to fuse three helium-4 atoms into carbon-12; that process will have to wait tens of millions of years until the Universe's first stars form!

But these nuclei are stable, and there will also be a trace amount of helium-3 (which tritium will also decay into, eventually), deuterium (hydrogen-2), and very small amounts of lithium (and probably even smaller amounts of beryllium) formed by very rare fusion reactions.

Image credit: NASA, WMAP Science Team and Gary Steigman.

But the overwhelming majority of neutrons -- 99.9%+ of them -- wind up locked up in helium-4 nuclei. If the matter in the Universe contained just a hair over 12% neutrons and just a hair under 88% protons just prior to nucleosynthesis (the fusion into heavier elements), that means that all of those neutrons and and equal amount (just over 12% of the Universe) of protons winds up becoming helium-4: a total of 24-to-25% of the mass, leaving 75-to-76% of the Universe as protons, or hydrogen nuclei.

Image credit: Ned Wright, via his excellent Cosmology tutorial at UCLA.

So that's why, by mass, we say 75-76% was hydrogen and 24-25% was helium. But each helium nucleus is around four times the mass of a hydrogen nucleus, which means that, by number of atoms, the Universe is around 92% hydrogen and 8% helium.

This primordial, unprocessed material has actually been detected observationally, and is one of the three cornerstones of the Big Bang, along with Hubble expansion and the cosmic microwave background. And that's where all the elements in the Universe started from! Everything you are, everything you know, and every material object you've ever interacted with came from this primordial sea of protons and neutrons, and was once a mere collections of hydrogen and helium atoms. And then the Universe happened...

Image credit: NASA / JPL-Caltech / Spitzer / IRAC / N. Flagley and the MIPSGAL team.

and here it all is! And that's where -- if you go way, way back -- all the atoms came from.

esiegel Fri, 07/05/2013 - 09:11

Tags

Yet another nice article. I like the way the illustrations break up the text and make it easy reading.

Something that doesn't feature in the standard description is that you can "melt" hadrons in a "quark-gluon plasma", see http://physicsworld.com/cws/article/print/2009/sep/01/of-gluons-atoms-a…. I think this might turn out to be important for baryon and lepton asymmetry myself, wherein positrons are actually more like protons than electrons are. That's another one for another day!

Rad! I'm always curious as to why and how there was "small amounts of lithium" in the very early stages on the universe, but I think I grok the random fusion chain now. If it is something else, please tell me.

Also, Ethan, relevant to this post: a friend and very talented musician/artist Kim Boekbinder AKA The Impossible Girl just released a new space-themed album, called "The Sky is Calling"!!

Youtube for the first music video from the album, for the song "Stellar Alchemist" here: http://www.youtube.com/watch?v=ENJKo5jqjUw&feature=youtu.be
You and readers will appreciate it I'm sure.

Excuse me for thinking, but what if time is more than a marker of passage, what if it is the fundamental particle, intertwined with space, what if it is time that exploded creating the big bang? Excuse me for thinking.

You will need to actually specify what the hell you're on about, Tony. Because what you wrote just there was meaningless garbage.

What if you reversed the osmosis of the dilithium crystals and injected red matter to cause a time skip in a bagel?

xcuse my garbage.

No.

Wow, what is your definition of time. Why does time slow down near a large mass such as a black hole, why does time stop at the speed of light, the twins scenario. Why should time vary at all. It does, but why? What is time? Explain it to me. Why is the arrow of time what it is? I know you must know, not just speculation.

wow, If time stopped so would the universe instantly disappear. The Universe and time began at the same instant, so, maybe time is a something, maybe it's the power behind inflation. the basic wave function of all functions, that permeates all of space and matter. When people have experience NDE they say that time essentially stopped they couldn't tell if they had been gone for a second or a much longer time, so if this is true than time is a property of this universe alone, barring other universes that may exist, and this is also essentially speculation by Physicists, though I believe this may well be. So, science begins with imagination, and a desire to know.

When people have experience NDE

they are experiencing a chemical imbalance in the brain, nothing more - certainly nothing indicative of any deep notions about the universe.

Everyone experiences an NDE.

It's called "life".

"If time stopped so would the universe instantly disappear."

If time stopped, how is there an instant for something to disappear in?

The ancient Greeks had this problem, Zeno's paradox it is called.

Most people know of it but know that it is a fallacious reasoning problem, even if they don't know why.

You're still at the "Well, how DOES the arrow catch up to the tortoise?!?!".

"Why does time slow down near a large mass such as a black hole"

It doesn't. For the thing in that situation, time moves just as fast as it always did.

Maybe Ethan can explain this at some time.

wow, time does dilate relative to other objects who are not near the massive object.

Tony Rotz: You're confusing the physics notion of subjective time -- the relative timing of events may differ for different observers -- with the psychological notion of time perception. This is what your brain does, creating a cohesive narrative and giving you a sense of how much time passes. And just like everything else our brain does on our behalf, this involves a lot of fudging, filling in blanks, and outright lies.

There have been experiments done on NDEs and the perception that time slows down. While people in the experiments claimed that time slowed down and they could see everything in complete detail, their measured ability to recall those details correctly was no better than normal. Events that occurred too quickly to be perceived normally were also not perceived during the experiment.

In short, it truly is only the *perception* of time that changes. Not actual time, and not any other form of perception. The brain just fills in a bunch of details because it decided that event took much longer than it really did, and therefore you should have been able to see a lot more than you normally would. So what you get is a seemingly self-consistent picture (cus that's what your brain does) that falls apart when put to the test.

Gleaning physical insight from this psychological quirk is like believing that the moving-image optical illusions Ethan posted a week or two back means the images are REALLY moving.

Oh and by the way this is expected -- as Wow hinted, the changes in time are only visible *relative* to something else. No matter how "fast" or "slow" time is going relative to somewhere else, you will always observe time locally to be going at the same rate (think about it).

The chance of you comprehending a response is zero, Tony.

wow, why don't you use your real name, if your going to insult someone instead of hiding behind a wow. What's wrong with you? This blog shouldn't be used for insults, grow up. Your hatred is showing.

I'll stay off this blog rather than cause your hatred to grow. good bye.

Uh, what the hell? No hate, dude, just completely sick and tired of meaningless drivel.

Tony, why do I have to use my real name? It is no more me than my pseudonym. Giving it to you will give you no more info than a fake one and you can find nothing else out about me from it.

If someone measures 50 grams 20 times, they still get 1Kg even if the mass of a standard kilogram changes. If the yardstick is half as long, but everything around it is also half as long... This is why it's called relativity. ;)

It's a scaling problem. Does that explain it? This is related to the term 'dimensionless constants'. Like if the universe octupled in volume but the reactions as related to the size of an object stayed the same, we would not be able to tell that everything became twice as far away. For extra fun, read up on something called 'doubly special relativity' and all the issues involved in a maximum frequency/velocity/density and Planck units. It's not like we can actually test to see what happens when a photon has a wavelength approaching the Planck length unit. It would take more energy than we can even imagine being applied by human technology.

@Helyx, great lyrics and videoclip indeed. I already bookmarked it :)

Anyway, I made a Dutch translation of this article:

http://www.astroblogs.nl/2013/07/15/nucleosynthese-en-de-oerknal/

love the pics on this web page excuse me for being a geek but its awesome.

SCIANCE RULES!!!!!!!!!!!!!!!

everything is fine but you unlike every other major site in the world has missed the most important point, how did protons, neutrons, electrons, quarks came into existence FROM NOTHING? the big bang was just a massive explosion that only had light, where did all these constituents come from?

There's a thread for that

http://scienceblogs.com/startswithabang/2011/02/02/can-you-get-somethin…

odd that you complained well after that thread was started about how no site had such a thread...

So the question is: if a site had such a conversation, would you ever have bothered to read it?

I think the answer is an emphatic "no".

Every going day, the number of thinking brains is increasing; this is pushing us (humans) of understanding more and more. Now a days, more than 6 billion thinking brains making a strong power to explore whether by NASA rockets or even by seating, drinking a cup of tea, thinking scientifically in it.
Human found that it’s a rounding ball, not a flat earth, visited the moon, well, voyjar has did a good job far away of home, in the same time scientists are working home making diamond in the labs,
The point I'm trying to clear is that everyone has the rights to think and to share, not has the rights only but HAS TO THINK AND SHARE, so please respect everyone's point.
Wish you all the best, hamed from Saudi hamedalshahrani@yahoo.com

Wow...Wow, it's people like you that slow down the progress of humanity. Just reading the comments above between you and Tony was the most frustrating aspect of my day. What do you get out of being so arrogantly pompous? I agree, what Tony was saying may not align with what science currently tells us, but it's an interesting thought and you attack it as if you know all the answers to the universe. Who knows what we might discover in another 100 years - the way we understand and interpret the universe is constantly changing as we discover more incredible things. I'm not saying your argument was invalid or incorrect, you seem to be very intelligent; I'm just saying that it makes you look incredibly weak by instantly shutting down a fellow thinker who is just trying to have an intellectual "outside of the box" conversation.

I'm sure you will respond with some sort of arrogant remark - well so be it - it was just hard to read this thread without trying to teach you a little bit of decency.

John Schmit, that is well said. I had the exact same reaction from reading this thread.

If the universe is expanding why the earth's distance to the sun is still the same? If the universe started from nothing or from tiny particle how did it grow?

@mario de vera #35: Because (1) the Earth and Sun are bound together gravitationally, and (2) the expansion rate is so tiny as to be unmeasurable on Solar System scales!

The expansion rate, today, is 67 km/s per megaparsec. That is, two galaxies one megaparsec apart would be separating at 67 km/s. Two galaxies ten megaparsecs apart would be separating at 670 km/s. And so on.

The Earth and Sun are 150 million km apart (on average). That's five TRILLIONTHS of a megaparsec (4.86e-12 Mpc). So the cosmic expansion is trying to separate the Earth and Sun at a rate of 0.32 billionths of a km/s (0.32 microns/second). The Sun's gravity is such that escape velocity at the position of Earth's orbit is 30 km/s, or ten billion times faster than the cosmic expansion rate. To paraphrase an old song, "Gravity, gravity will keep us together..."

It isn't just Wow's comments to Tony, but also to Big Sooka, that make me agree with IMHO and John's sentiments re pompous arrogance. The amusing thing is that Wow is hiding behind the theories we accept today that have been cleverly woven together by others, not by Wow. Judging from the attitude to others, I wouldn't even suggest Wow is intelligent. All that has come from Wow's input here is regurgitation gleaned by memorising detail. Not even one attempt at an imaginative original thought. Like what initiates particle/antiparticle creation? Why is the speed of light limited ? Is the cosmological principle valid ? Hide behind the shoulders of giants then, Wow.

@ian b #37: Wow has an excruciatingly harsh response to non-scientific comments. However, his responses are quite on target technically. If you are having a _scientific_ discussion, then you are best served by sticking with known science.

If you want to have an idly speculative discussion, then by all means wander off into non-scientific speculations.

Smart people, Stupid questions... (Not to offend anyone, we all have stupid questions.)

If the universe started from a single point, and that it is expanding, how is it possible for two galaxies to collide (eg: milky way and andromeda collision)?

Because space is moving, but the things are moving in that space.

Hi
You write:"By time this happens, though, the Universe is nearly four minutes old, and is far too diffuse and cold to undergo the next major step of fusion that happens in stars, which is to fuse three helium-4 atoms into carbon-12; that process will have to wait tens of millions of years until the Universe’s first stars form!"

I present my hypothesis: carbon production :)
7Li(p,y)8Be*(a,y)12C*
Link:https://scontent-vie1-1.xx.fbcdn.net/hphotos-xta1/v/t1.0-9/12243382_108…
Lithium-proton reaction channels:
Link:https://scontent-vie1-1.xx.fbcdn.net/hphotos-xpa1/v/t1.0-9/12310578_109…
This hypothesis explains: 2H, 6Li, 7Be, n, Nucleosynthesis.
Regards nyemi

Write it up and present to a peer reviewed paper where your ideas will be discussed and viewed by those able to critique it without them worrying about wasting time on a crank site or vanity blog. When it gets past peer review, let us know.

Ok :).
Thank you, your reply.
Physics: "that which is not forbidden is mandatory".

Regards nyemi

Why on earth do you claim that? Obviously, the answers you got did not manage to make any impression on your knowledge.

That which is not forbidden is possible.

Regards, the genus homo sapiens sapiens.

Link:http://arxiv.org/abs/1602.07298

Yeah, still says fuck all about how you come to the assertion "that which is not forbidden is mandatory”.

Quite why you think it was relevant is probably from the same lack of intelligence as caused the claim in the first place.

Perhaps someone here can help me, because it is an extremely arduous task to find the answer on Google.

Stars fuse hydrogen into etc. etc. and dies once most of its hydrogen is depleted. Some stars supernova, thereby creating a nebula. More stars are born from this and the whole process starts over.

My question is, since most of the hydrogen was fused in the first star, where does all the hydrogen come from to fuel the next generation of stars?

Any help would be appreciated.

a supernova does not necessarily create new stars unless it is in a giant nebula itself, like the eagle nebula, in which case it is just adding to the elements in the cloud, a lone star like ours that supernovas just blows its cloud into space, like the crab nebula

@Andre #51: What you described for a star's lifetime applies fairly well to the Sun and other light-weight stars. The heaviest stars, the ones which produce supernovae and heavy elements, don't burn "most of [their] hydrogen." Rather, what we believe happens is that in their dense cores the hydrogen all burns to helium, then to carbon and oxygen, then to silicon, and so on up to iron. Since the temperature and pressure both get lower as you move out from the core, what we expect is that there will be "layers" (probably somewhat mixed) where different kinds of fusion are occurring. The outer envelope of the star (with a significant part of the star's mass) is likely to still be mostly hydrogen by the time the star explodes.

At the same time, when a supernova does happen and spreads heavy elements out into the nearby environment, that material is going to be mixed together with the mostly hydrogen and helium which is already there.

"75-76% of the Universe is hydrogen, 24-25% is helium." 101%?! What about the other elements?

Usually, this is explained as this Universe is ~74% hydrogen, ~24% helium, and ~2% all the other elements.

“75-76% of the Universe is hydrogen, 24-25% is helium.” 101%?! What about the other elements?

You've modified the text. It would be best to go back to the beginning and note the words "at that time."

Missions to Mars and Nuclear Fusion

esiegel — Wed, 17 Apr 2013 13:08:26 +0000

Missions to Mars and Nuclear Fusion

“We are much closer today to being able to send humans to Mars than we were to being able to send men to the moon in 1961, and we were there eight years later. Given the will, we could have humans on Mars within a decade.” -Robert Zubrin

Of all the planets in the Solar System beyond our own, none has captured our imagination quite like Mars has.

Image credit: NASA, via http://photojournal.jpl.nasa.gov/jpeg/PIA02570.jpg.

From science-fiction fans to scientists and everyone in between, our understanding of the red planet is presently greater than it ever has been in the past. With multiple landers, orbiters and rovers probing the Martian terrain, we're learned so much about the nearest neighboring planet that wouldn't boil our insides in a matter of seconds.

Image credit: NASA / JPL-Caltech / Cornell / Arizona State Univ.

But many of us dream not of learning about the geologic history of Mars nor of sending robotic explorers there, but of sending humans there, with possible long-term goals ranging from creating a permanent human outpost there to terraforming the entire planet to be potentially habitable to human beings.

Image credit: Wikimedia commons user Daein Ballard, under the GFDL.

The first step, of course, is landing a human being on Mars. Recently, there's been talk of developing a nuclear fusion engine that could cut the trip-time down to a mere 30 days, from the more usual 250 days. Although it's possible to get to Mars more quickly, we're much more concerned with getting to Mars these days using the least amount of energy, which also requires waiting for the proper launch window, something that occurs every 780 days between Earth and Mars.

Image credit: Georgia Tech's Satellite Communications & Navigation course.

Now, nuclear fusion would, of course, be an incredible boon to both interstellar spaceflight and to Earth's energy needs. Crackpot claims about cold fusion aside, nuclear fusion is the holy grail of energy, is a completely clean source of energy, has the ingredients for it in abundance here on Earth, and is a process that's known to happen throughout the Universe.

Image credit: ESA & NASA; Acknowledgments: D. de Martin and E. Olszewski.

Not just in stars, of course, where nuclear fusion is the process that powers the vast majority of them, but here on Earth, where we've achieved controlled nuclear fusion successfully in at least three different general ways.

Image credit: National Ignition Facility.

1.) Inertial Confinement Fusion. We take a pellet of hydrogen -- the fuel for this fusion reaction -- and compress it using many lasers that surround the pellet. The compression causes the hydrogen nuclei to fuse into heavier elements like helium, and releases a burst of energy. Unfortunately, we have not yet reached the break-even point, as it still takes more energy to operate the lasers than we've been able to get out of any fusion reaction we've created.

Image credit: ITER (International Thermonuclear Experimental Reactor).

2.) Magnetic Confinement Fusion. Instead of using mechanical compression, why not let the electromagnetic force do the confining work? Magnetic fields confine a superheated plasma of fusible material, and nuclear fusion reactions occur inside this Tokamak-style reactor. This concept was first used to fuse elements beginning in the 1950s, and since that time, Magnetic Confinement and Inertial Confinement have gone back-and-forth as each one inches closer to the break-even point, where the fusion energy out will exceed the input energy. That point has not yet been reached.

Image credit: General Fusion, Inc.

3.) Magnetized Target Fusion. In MTF, a superheated plasma is created and confined magnetically, but pistons surrounding it compress the fuel inside, creating a burst of nuclear fusion in the interior. This clever hybrid approach was developed by Michel Laberge, and has successfully fused hydrogen into helium, but has not overtaken either ICF or MCF as the closest candidate to the break-even point.

Of course, the new candidate approach for a Fusion Driven Rocket is different from all of these in detail, but is worth a look.

Image credit: University of Washington's Plasma Dynamics Lab, MSNW.

In this approach, a magnetically confined plasma has large metal rings built around it, which are made to implode and compress the plasma, which will not only trigger a fusion reaction, but also will expel the high-energy particles in one direction, creating a fantastic amount of thrust. It is, at this point, an unproven concept, but it's definitely worth keeping an eye on to see how it develops.

But this new possibility for nuclear fusion and a current mission to Mars are two separate issues, and should be handled totally separately. For the fusion issue, we should be working tirelessly to develop nuclear fusion; if we can make it work, we will have literally tens of thousands of years worth of clean energy, regardless of the fuel mechanism used. Yet it's presently funded at the rate of about one billion Euros a year in the EU (and a little less than that here in the USA), which is part of the reason that fusion progress happens slowly.

Image credit: NASA/JPL-Caltech.

On the other hand, we can be on Mars in less than a decade, if we want to. This has been true since the 1990s (at least); it just requires a sustained investment in getting there using the technology we already have. I don't even care if it takes a reality show to get us there, the important thing is to invest in going one step at a time, and that means taking that very first step -- putting a human on Mars -- is maybe the most important step of all.

We have the fundamental rocket and life-support technology and the know-how, and we have thousands upon thousands of people willing to go, even if they know they're going on a one-way trip. We have the will and we have the manpower, all we need is a sustained vision for us to get behind, and -- in less than a decade -- we'll take our species' first steps on another planet.

Image credit: Stefan Morrell. Sources: Christopher McKay, NASA Ames Research Center; James Graham, University of Wisconsin–Madison; Robert Zubrin, Mars Society; Margarita Marinova, California Institute of Technology.

Yes, it's fun to dream about the far future on Mars, but the important thing -- if we're at all serious about following our dreams into space -- is to take the first step now, and send humans to the red planet. We should never pin our hopes of going to Mars on the development of fundamentally new technology, or it will never happen on the timescales that we want it to. We're all longing for the stars, but on its own, longing is only going to get us so far.

Image credit: Jason Kinnan.

We need to invest in the long-term future like it's our only hope, while simultaneously stepping forward in the present to bring that future to reality. Whether we invest in nuclear fusion or not, we should be sending human beings to Mars. Whether we send human beings to Mars or not, we should be investing in nuclear fusion. And if-and-when we do develop and control nuclear fusion, it won't be a quicker trip to Mars that we set our sights on, but ever farther and more remote targets. There's a whole Universe out there, and shame on us if we choose not to explore it.

That's my vision on a mission to Mars, that's my vision on nuclear fusion, and that's my vision and hope for the future of humanity in this Universe.

esiegel Wed, 04/17/2013 - 09:08

Tags

The Cosmic Story of Carbon-14

esiegel — Mon, 04 Jun 2012 16:01:56 +0000

The Cosmic Story of Carbon-14

"Life exists in the universe only because the carbon atom possesses certain exceptional properties." -James Jeans

Here on Earth, every living thing is based around four fundamental, elemental building blocks of life: hydrogen, oxygen, nitrogen and, perhaps most importantly, carbon.

Image Credit: Robert Johnson / University of Pennsylvania.

From diamonds to nanotubes to DNA, carbon is indispensable for constructing practically all of the most intricate structures we know of. Most of the carbon in our world comes from long-dead stars, in the form of Carbon-12: carbon atoms containing six neutrons in their nucleus. About 1.1% of all carbon is Carbon-13, with one extra neutron. But there is another form of carbon that, while not at all abundant, is definitely worth talking about.

Image credit: Press & Silver.

Carbon-14, or carbon atoms with eight neutrons in their nuclei, is unstable, and is so rare that only one-in-a-trillion carbon atoms are carbon-14. With a half-life of just over 5,000 years, any Carbon-14 atoms that were created in stars, billions of years ago, have long since decayed away into nitrogen atoms.

Image credit: Steve Gagnon at Jefferson Lab.

But there are small, but not quite negligible amounts of carbon-14 present in all the organic life that we know, including in our own bodies. The way it gets here is, literally, cosmic.

Image credit: Simon Swordy (U. Chicago), NASA.

From across the galaxy and across the Universe, from stars (including our Sun), pulsars, black holes and more, space is flooded with high-energy particles known as cosmic rays. Most frequently, cosmic rays are protons, but a handful are heavier ions and a few are even humble electrons. But once they interact with the atmosphere, look out!

Image credit: University of New Hampshire.

They produce showers of subatomic particles of many different types, including -- for our purposes -- the all important neutron. The reason neutrons are so important is because our atmosphere is 78% nitrogen, which you may remember as the thing that carbon-14 decays into.

Well, if carbon-14 can decay into nitrogen-14 and other stuff, then we can create carbon-14 by combining nitrogen-14 with the proper stuff. In this case, that happens to be a neutron, which allows us to do this:

Image credit: Wikimedia Commons, users NikNaks, Spacexplosion, and Sgbeer.

Once you create carbon-14, it behaves just like any other atom of carbon, readily forming CO₂ (a.k.a., carbon dioxide) and mixing throughout the atmosphere and oceans, easily making its way into living organisms into a well-understood equilibrium. As far as we can tell, the levels of carbon-14 throughout the world have remained roughly constant throughout the past few millenia, so that when an organism dies and the carbon-14 decays, we can measure how long ago it became deceased by measuring the ratio of carbon-14 to its normal carbon-12.

The only major fluctuation we know of occurred when we began detonating nuclear weapons in the open air, back in the mid-20th Century. If you ever wondered why nuclear tests are now performed underground, this is why.

Image credit: Wikimedia Commons, user Hokanomono.

So you can imagine it came as a shock when, just yesterday, nature released a paper showing a big, short-lived spike in carbon-14 levels way back in the 8^th Century! By looking at the tree rings of ancient Japanese Cedars, you can see a rise in the concentration of carbon-14 that starts in the 770s, peaks in the 780s and then falls off.

Image credit: Fusa Miyake, Kentaro Nagaya, Kimiaki Masuda & Toshio Nakamura, 2012.

What does this correspond to, in terms of creating this carbon-14? Well, there were no nearby supernovae that happened at that time, so that's out. There's no evidence of an unusually large solar flare or any other bizarre solar activity, so that can't be the culprit, either. What this appears to correspond to, at least at this preliminary stage, is an increase in cosmic rays during the year 774-775.

Image credit: Fusa Miyake, Kentaro Nagaya, Kimiaki Masuda & Toshio Nakamura, 2012.

Now, since we've been watching the skies, we've never seen an increase in levels like this, but it's only recently that our sophistication in measuring the carbon-14 levels in old tree rings like this has allowed us to test this.

The follow-up? Looks like we're going to have to unearth more old trees that can be radiocarbon-dated back to these years, and see whether they have elevated levels of carbon-14 in them. If not, then it's conceivable that these trees are just flukes, or that there was a mistake done in the analysis. But that doesn't seem likely; there is data from North American and European trees that this is consistent with! If this is confirmed, then there was very likely an extremely large increase in cosmic radiation over a very short period of time, the likes of which we've never seen or recorded, until now.

What could've caused an influx of cosmic rays like this? While there are many possibilities, I wouldn't count out a relatively nearby, flaring black hole!

Image credit: NASA / Goddard Space Flight Center.

The Universe may never cease to surprise us, but we may never cease, as long as we exist, to figure out exactly why it does the things that it does. How remarkable is this!

Thanks to Sarah Kavassilis for suggesting this story; it's a great one!

esiegel Mon, 06/04/2012 - 12:01

Tags

A starship engine revving up in the Edgeworth–Kuiper belt? [just joshing]

I did not know the origin or Carbon-14. Very nice explanation.

Hmm, I don't think a nearby black hole. It would have to be within 5,000 light years or so.

But the sun of course is continuous nuclear detonations. But why would it produce an extra amount of carbon-14? My off the wall crazy thought is, remember the shoemaker comet.

"Comet Shoemaker–Levy 9 (formally designated D/1993 F2) was a comet that broke apart and collided with Jupiter in July 1994... The collision provided new information about Jupiter and highlighted its role in reducing space debris in the inner Solar System... Galileo detected a fireball which reached a peak temperature of about 24,000 K, compared to the typical Jovian cloudtop temperature of about 130 K... Over the next 6 days, 21 distinct impacts were observed, with the largest coming on July 18 at 07:33 UTC when fragment G struck Jupiter. This impact created a giant dark spot over 12,000 km across, and was estimated to have released an energy equivalent to 6,000,000 megatons of TNT (600 times the world's nuclear arsenal)..." Wikipedia

OK so that comet striking Jupiter was equivalent to "600 times the world's nuclear arsenal". It sounds to me that such an event (assuming it trigger a nuclear event) would result in an increase of carbon-14 showering down upon the earth. After figuring the time of travel of such Jupiter debri to Earth.

Assuming we found such carbon-14 debri on earth associated with the Shoemaker–Levy 9 comet; then I hypothesize that such a similar comet impact into the sun or Jupiter could account for the carbon-14 event of the 8th century.

http://www.sciencenews.org/pages/pdfs/data/1995/147-21/14721-19.pdf
"To test more rigorously whether the gases indeed came from fragments of Shoemaker-Levy 9, Crisp plans to measure the isotopic ratios of oxygen, carbon, and hydrogen, which have characteristic values in comets." this is all I can find about analyzing the debri, but I suspect somebody has done it and determined if there is nuclear debri.

OK that's my 2 cents.

my 2nd hypothesis.

The Tunguska event in Russia in 1908 ... "The explosion, having the hypocenter, (60.885833°N, 101.894444°E), is believed to have been caused by the air burst of a large meteoroid or comet fragment at an altitude of 5–10 kilometres (3–6 mi) above the Earth's surface.. It is the largest impact event in recorded history... Estimates of the energy of the blast range from 5 to as high as 30 megatons of TNT... about 1,000 times more powerful than the atomic bomb dropped on Hiroshima, Japan, and about one-third the power of the Tsar Bomba, the largest nuclear weapon ever detonated. The explosion knocked over an estimated 80 million trees covering 2,150 square kilometres (830 sq mi). It is estimated that the shock wave from the blast would have measured 5.0 on the Richter scale. " Wikipedia

Hypothesis 2: Such an event occured in the 8th century.

Check to see if there is increased carbon-14 levels in tree ring in russia and elsewhere associated with the 1908 Tunguska event. If so calculate the relative size of the 8th century event versus the Tunguska event.

OK, please knock down and destroy my two hypotheses or tell me they are reasonable or how to make them more reasonable. or your better hypotheses. Every which way, I learn. thanks.

concerning OKThen's suggestion about comet strikes creating lots of C-14 in the past: A large comet strike would produce huge amounts of X-Ray photons. But an X-Ray photon has only a few thousand electron volts (EV) - That's many orders of magnitude less than the cosmic rays that routinely transform Nitrogen to C-14. I doubt that zillions of X-Ray photons from a comet strike would create C-14, as does a single cosmic ray packing trillions of EV.

Cue Young Earth Creationists using this to cast doubts on radioisotopic dating in 3...2...1...

The energies required to do nuclear fusion/fission are so large that no local events like cometary impacts can create the sources. That's why something like a black hole is required. There are several large energy sources that are possible but not that many that could flood our atmosphere with nuclear hammers. Remember too that Carbon14 has to be created locally since none survives long enough to traverse interstellar or intergalactic space. And yes, this may force Carbon14 dating revisions and make the use of this kind of dating even more complex.

This is really fascinating. I'd wondered where C14 came from, since it has such a (relatively) short half-life. It would have to have some steady, continuous rate of replenishment, but I had no idea what the mechanism might have been. Now that I've heard it explained, it makes perfect sense.

@OKThen: (1) The cosmic rays Ethan described are not themselves, C-14. Rather, they (usually high-energy protons) hit the top of the atmosphere and produce a shower of secondary particles. Some of those secondary particles are neutrons, which in turn collide with nitrogen atoms in the atmosphere to convert the N-14 into C-14 (Ethan's sixth figure).

(2) The Tunguska event, just like Shoemaker-Levy hitting Jupiter, was just a really large "chemical" explosion. Nothing nuclear, no high-energy particles or neutrons. Just a really big rock getting really, really hot and going blooey. There have been many wonderful hypotheses about Tunguska (everything from a blob of antimatter to a nuclear-powered alien spacecraft), but the blast pattern and energy release are entirely consistent with a simple meteroroid ablating and vaporising in the atmosphere.

OKThen- I like the way you think, but as I understand it, a Tunguska-type event, or a solar comet impact would require something moving at relativistic speeds to produce the energy required to fuse N14 into C14.

"Give a man a relativistic rock, and he will shatter a planet today. Teach him to do the math himself, and he will shatter planets for the rest of his life."

Ethan, speaking of blackholes, do you have any insights regarding this news? Sounds quite amazing!
http://freeinternetpress.com//story/Giant-Black-Hole-Ejected-Out-Of-Hom…

Hi Ethan

Can you explain the y axes on your graphs please? Unless these are very local peaks quickly reduced by atmospheric mixing, I don't see how the levels can fall again with anything other than a half life of C14.

Comet impact on Earth, maybe not.... comet impact on the Sun, disturbing the photosphere to stimulate increased activity there? From a position of complete ignorance, and in the knowledge that small comet impacts don't have a noticeable effect....

I've got to cringe on seeing the fit lines through that discontinuous data, though - no way should there be a rising period, it is clearly an step-type change. Maybe that's the point they're trying to make, of course.

David L @0308: Radioactive decay is not the only way C14 is removed from the atmosphere. It also gets incorporated into plants, and this can be a much shorter timescale. Some of the C14 gets put back through decay of vegetation (or animals eating the vegetation and breathing out some of the C14), but this process is slower than the plant uptake (effectively, the C14 thus released is an average over years to decades, while the uptake rate depends on the instantaneous concentration). Meanwhile, more C14 is created at a rate closer to normal. The axes in the paper by Miyake et al. are fractional deviations from some "normal" concentration.

My own hypothesis: It is well known that cosmic ray flux is anticorrelated with the solar cycle. Perhaps there was an unusually deep solar minimum in the 770s, so that the cosmic ray flux was unusually high. Test: we just had an unusually deep solar minimum in 2007-2010, so we should be able to tell within a decade if there was a similar increase in C14 uptake by plants.

I did understand that the cosmic rays (i.e. protons) collided with the atmosphere etc and N14. Ethan's explanation was clear to me.

But I didn't understand, how far astronomically C14 might travel hence my 5000 light year remark as well I did not understand if C14 might travel relativistically. Apparently not observed and thus not too likely. I suppose any relativistic C14 would collide with something long before it reached Earth. Oh well.

As well I did not understand; if a large physical impact (and consequent chemical reaction) could ever be able to trigger a nuclear reaction. OK I accept your credibility in this matter. i.e. a very large physical impact or chemical reaction even if 100's and 1000's times more explosive than a nuclear weapon will NOT trigger a fission or fusion reaction.

So I dug a little bit more.
"At the temperatures and densities in stellar cores the rates of fusion reactions are notoriously slow. For example, at solar core temperature (T ≈ 15 MK) and density (160 g/cm3), the energy release rate is only 276 μW/cm3—about a quarter of the volumetric rate at which a resting human body generates heat.[20] Thus, reproduction of stellar core conditions in a lab for nuclear fusion power production is completely impractical. Because nuclear reaction rates strongly depend on temperature (exp(−E/kT)), achieving reasonable energy production rates in terrestrial fusion reactors requires 10–100 times higher temperatures (compared to stellar interiors): T ≈ 0.1–1.0 GK." wikipedia. Hot, hot, very hot!!

So, it looks like even at 15 million K (Kelvin) the temperature of the sun would cause a puny nuclear reaction. So the shoemaker-Levy comet's " peak temperature of (of impact) of about 24,000 K... (even) releasing the (explosive) energy equivalent to 6,000,000 megatons of TNT (600 times the world’s nuclear arsenal)" is not enough. Yikes! I did not know.

Thus large astronomical bodies (comets and planets) colliding will not make a nuclear reaction; because physical comet collisions can not focus enough explosive energy to a small enough space.

I never thought of it before; so thank folks for the education..

Just to continue with my education in public.

"Ultra High Energy Cosmic Ray Acceleration in Engine-driven Relativistic Supernovae... The origin of the highest energy cosmic rays remains an enigma. They offer a window to
new physics, including tests of physical laws relevant to their propagation and interactions, at energies unattainable by terrestrial accelerators. They must be accelerated locally, as otherwise background radiations would severely suppress the ﬂux of protons and nuclei, at energies above the Greisen-Zatsepin-Kuzmin (GZK) limit (∼ 60EeV=6 × 10^19 eV). Nearby Gamma Ray Bursts (GRBs), Hypernovae, Active Galactic Nuclei (AGNs) and their ﬂares, have all been suggested and debated as possible sources." http://arxiv.org/pdf/1012.0850v1.pdf

"About 89% of cosmic rays are simple protons or hydrogen nuclei, 10% are helium nuclei or alpha particles, and 1% are the nuclei of heavier elements. These nuclei constitute 99% of the cosmic rays. Solitary electrons (much like beta particles, although their ultimate source is unknown) constitute much of the remaining 1%." wikipedia

But look at this.
"The problems of the origin and propagation of the charged cosmic rays (CRs) in the Galaxy are among the major subjects of the modern astrophysics. It is generally accepted that primary CR nuclei such as H, He, C, N and O, are accelerated in supernova remnants (SNRs) via diﬀusive shock acceleration (DSA) mechanisms, that produce power-law momentum spectra (Drury, 1983). At relativistic energies S ∝ p^−ν
∼ E^−ν." http://arxiv.org/pdf/1203.6094v1.pdf

So there is Carbon nuclei in cosmic rays and hence Carbon-14 and also relativistic cosmic rays. But rereading Ethan's post. Hmm, Ethan has a simpler hypothesis. The increase C14 is not from primary cosmic rays but from the atmosphere. OK.

Now, I better understand Ethan's post and his hypothesis. I still don't like the idea of a "relatively nearby, flaring black hole". Nor do I understand the "many pssibilities" that could cause an "influx of cosmic rays like this".

But Eric Lund's explanation above makes sense to me. thanks for that.

Hey Ethan, I just noticed the blog comments are no longer numbered. How are we ever going to discuss each others comments when you post a topic that gets hundreds of comments. Oh well.

Cool mystery, though I'm as interested in the origin of carbon-14 on Earth, which I'd apparently had wrong all these years. I thought it was part of the decay chain of longer-lived radioisotopes in the crust, like radon or, in a roundabout way, helium. One more way to avoid making a fool out of myself in the future, thanks! :D

How can we exclude a supernova over the southern hemisphere? I can't think of any history keeping culture which would have kept records of an event in the 8th century not visible from northern latitudes.

@ Michael Fisher

It's Reavers. They run without Core Containment. Raiding party must have come by and loose radiation from their core raised the ambient C14 levels . . .

But, on an actually non-tongue-in-cheek note, another great article, Ethan. Be an interesting mystery to solve.

Mu @0703: We can't rule out a supernova sufficiently close to the South Celestial Pole, but we can rule out anything more than 20 degrees away (and we can probably tighten that bound). There were literate societies at tropical latitudes in Arabia and India, and perhaps the Maya would have noticed something and carved it on a stela. A supernova close enough to produce this effect would be bright enough to be visible during the day, so dark skies are not a requirement. I don't know of any candidate objects for supernova remnants in that part of the sky, but as Ethan has mentioned in other posts, a pair-instability supernova would leave no remnant.

Nuclear power reactors that run on uranium also produces C14

So maybe a volcano, or a meteorite impact like OKThen suggested, might have brought rich uranium ores closer to the surface and high into the air, and along with some thermal diffusion ...
Eastern Mongolia (Dornod) which isn't that far from Japan has open cut uranium mines, and along with the wind ...

... or is this too far fetched?

GRB?

Chelle - nope, the isotopic ratios of U235 to U238 in the 700s was basically what it it is now: too low for any sort of spontaneous chain reaction in natural U oxides.* However, you might be interested in looking up the Oklo natural reactor (just google it) - what you suggest did happen, but it was a billion years ago when the isotopic ratios were different, not 1,000 years ago.

*IIRC from my nuke physcs, with today's isotopic ratios, nature would have to produce a pure, metallic (natural) U blob 14m on a side to to get any chain reaction going at all, and U doesn't generally form the metallic form in nature, oxides are more stable.

Eric thanks. Pretty neat, what a comet smashing into a planet can't do; a little groundwater in a uranium can accomplish.

OkThen- Thanks for the Oklo tip. I'd never heard of that before. Amazing!

eric, I don't understand your argument very well. A nuclear bomb is set of with explosives to start a chain-reaction. So why wouldn't a Volcano or a Meteorite impact in a Uranium rich environment, cause fission on a mass scale, there for not a chain reaction, but still a large production of C14 could be possible, no?

Chelle
A nuclear fusion bomb (hydrogen bob) is set off by a nuclear fission bomb (uranium). A physical collision or chemical explosion is not powerful enough to create the energy densities necessary nuclear fusion, i.e. to overcome the electrostatic repulsion of the positively charged nuclei.

On the other hand nuclear fission only requires a critical mass of U-235 or other suitable radioactive isotope. And radioactive decay compounds exponentially as a critical mass is brought together.

Check wiki for a more complete skinny.

chelle, you need the right elemental AND isotope combination to get a chain reaction. Natural uranium is a mixture of over 99% of uranium 238, and only about 0.7% of easily fissioned uranium 235. This ratio is constant world wide. Only the uranium 235 can spontaneously fission if you get enough of it to form a critical mass (which you're doing with the explosives in a nuclear bomb), and you can't get enough of it close together if it's diluted by a lot a U238. The way you get U238 to fission is by using it as a tamper around a nuclear bomb; read up on the Castle Bravo mishap.

@OKThen

What about this:
http://en.wikipedia.org/wiki/Gun-type_fission_weapon

It is inefficient but than again the peak of C14 found in the Japanese Cedars isn't so far out of the normal.

@Mu

Yes for a chain-reaction, but that's not what I'm suggesting here. Only the production of a lot of C14, and a Volcano outburst or Meteorite impact might cause a lot of individual fission events and hurdle the by-products into the atmosphere.

btw isotopes that's why I mentioned thermal diffusion in my first post, and both cases might set up some 'natural' diffusion processing activity:
http://en.wikipedia.org/wiki/Uranium_enrichment#Thermal_diffusion
http://en.wikipedia.org/wiki/Uranium_enrichment#Aerodynamic_processes

I rest my case : )

chelle, several comments:
(1) the production of C14 requires thermal neutrons (neutrons that have only a few eV of kinetic energy). Uranium in nature produces fast neutrons, with kinetic energies in the MeV range. So a given amount of uranium will not contribute much to C14 production compared to the same amount of cosmic rays hitting the atmosphere.

(2) I'm unclear what you think a volcano or meteor impact contributes. I thought you were saying that these violent events would produce chain reactions (which create more thermal neutrons) similar to what goes on in a nuclear reactor. But based on your last post, I am no longer sure. Maybe you are saying that volcanos and meteors could bring more uranium ore to the surface of the earth? If so, see (1); normal, run-of-the mill uranium ore produces neutrons that are too high in energy to effectively make C14. They need a moderator to produce thermal neutrons.

(3) a volcano or meteorite would be very unlikely to cause a chain reaction. Our bombs produce chain reactions via implosion: forcing stuff together. Volcanos wouldn't do that, neither would a meteorite impact (with the exception of the point of impact, for a short period of time). I suppose that if a meteorite very rich in U-235 hit a U-nat deposit on earth, billions of years ago when our deposits were also rich in U-235, you might get a chain reaction. That's quite a farfetched scenario, however.

(4) I'm not sure what either of the separation methods you mention have to do with the discussion. They both require very specific and stable engineering circumstances. I believe they also require uranium in a gaseous form, which it doesn't exist in naturally on earth. And they probably also require that the uranium go through the same process many hundreds of times, to increase enrichment to a reasonable level. Meteorite hits and volcanic explosions don't, it seems to me, provide any of the needed circumstances.

@eric

(1): "Carbon-14 can also be produced by other neutron reactions, including in particular ... with thermal neutrons, and 15N(n,d)14C and 16O(n,3He)14C with fast neutrons."
http://en.wikipedia.org/wiki/Carbon-14#Other_carbon-14_sources

(2): You say that they need a moderator, wouldn't there be lots of water available for an emerging underwater volcano, or what about a very rainy or snowy season for a Meteorite?

(4): That's true it's just a lot of speculation from my part, but maybe once every 2000 years such a unique circumstances might take place as those trees show us ; )

Chelle, no. The degree of enrichment needed for a gun-type atomic explosion is ~90% and use of pure metallic uranium. Metallic uranium doesn't exist in nature. You need a critical mass of that isotopic composition with is ~50 kg or so. That is why modern nuclear weapons use plutonium which has a critical mass of ~10 kg.

What is important is the density of fissile atoms. You can increase that density by packing more atoms into a smaller volume, but if there are impurity atoms, either non-fissile isotopes of uranium (U238), or non-fissile atoms like oxygen as in U2O3, the required density of fissile uranium atoms is harder to reach.

The energy release once there is a critical mass occurs exponentially, with the magnitude of the exponent dependent on the density of fissile atoms. As the energy release increases, the mass gets hotter, and as it gets hotter, it tends to expand. To get a nuclear explosion of high yield, you need a very short time constant for the energy increase. That is why they use pure isotopes and metallic fissile materials. The time constant they get is on the order of a nanosecond. As the fissioning occurs, the energy release rate approximately doubles every time constant. That means that virtually all of the energy is released in the last few doublings, as the fissioning material gets so hot that it flies apart with a time constant of a nanosecond. 0.1 meter in a nanosecond is 100,000 km/sec. That is fast enough that you can't neglect relativistic effects.

Moderators are not useful in atomic weapons. Moderators slow neutrons, which makes the time constant longer. That is desirable for reactors where you want a very slow time constant so that the reactor can be controlled, but undesirable when you want very high energy release rate. If the time constant was milliseconds, then the characteristic velocity would be 0.1 meter in 0.001 second, or 100 m/s. If the uranium got hot enough to vaporize, it would expand as a gas faster than that. That is how hot it would get, hot enough to vaporize but then it would expand and the nuclear reactions would stop.

Thermonuclear warheads generate energy via fusion of D + T. This produces 14 MeV neutrons and these are the neutrons that generate C14. Much of the C14 in the diagram came from the Tsar Bomba which was mostly fusion. It was set off October 1961, but it takes a while for the atmosphere to mix and C14 to get around.

A bit off-topic, and late to the thread, but I want to indicate a beautiful post about carbon-14 relating to our own finitude: http://tinyurl.com/carbon14-theseus . I've linked to a Google english translation of the original post in portuguese, which you can find clicking in my name. Hope you like it.

@daedalus2u

I never suggested here a chain-reaction like an a-bomb, I only thought of fission on a large scale. The reason I mentioned a "gun type fission weapon" was because it could cause fission, that's all. Scroll through the previous comments to catch up.

Scroll through the previous comments

Chelle

You seem to be suggesting that there is some other type of fission than what daedalus2u explains. There isn't; that was my misunderstanding too. Reread what daedulus2u explains.

@OKThen

Ok, I might be wrong.

Anyway, spontaneous fission does happen, and I thought that extreme high pressure and heat might possibly induce it:

"For naturally occurring thorium, uranium-235, and uranium-238, spontaneous fission does occur rarely, but in the vast majority of the radioactive decay of these atoms, alpha decay or beta decay occurs instead." - http://en.wikipedia.org/wiki/Spontaneous_fission

And what if a Volcano or Meteorite impact blows a lot of Uranium (and Nitrogen) high up into the atmosphere, than wouldn't those 'normal' cosmic ray-showers cause some fissioning in those heavy elements, and generate more C14 than normal?

"Anyway, spontaneous fission does happen"

This is called "radioactivity".

As to your theory on cosmic rays and volcanic/meteoric uranium:

a) the fluxes of cosmic rays are generally too low
b) the energies too high for a high cross-section for capture
c) the density of the uranium very very low

for this mechanism to create any measurably different C14 ratios.

Not to mention that a large event would be visible in geological strata.

@Wow

"Not to mention that a large event would be visible in geological strata."

I agree, although one remark: if you check the timeline of volcano's, there has been a lot of action between 710 and 800 CE with the outburst of the Pago and Dakataua, all part of the Bismarck Volcanic Arc in Papua New Guinea (http://en.wikipedia.org/wiki/Timetable_of_major_worldwide_volcanic_erup…)

It is a geographical area straight below Japan, and the C14 peak was in the 8th Century.

That's correct, chelle. But looks to be several orders of magnitude too small to produce the effect.

All that's really needed are a lof of slow neutrons. The capture cross section for N14 is much much higher for slow neutrons than fast ones. Okolo has a high concentration of uranium and moderators of the neutrinos and hence it has an "unnaturally enhanced" decay because of this moderation of the energies of the neitrons. Someone would have to come up with a much more effective way of turning that ash into slow neutrons than any naturally occurring process. Just as with Okolo.

Thing is, I'm not too sure of Ethan's proposal of a flaring black hole, I'd be more inclined to a nearby nova event. Much less energetic and, if it was highly isentropic, could still be intense enough on the earth to be a cause.

At the moment it seems to me we have only enough data to preclude options.

And the anomaly may have to go down as "just one of those things". I'm OK with that.

moderators of the *neutrons*, not neutrinos.

Duh...

Regarding the possible need to recalibrate carbon dating - I don't think so. Carbon dating has already been extensicely calibrated against dendrochronologocal records - tree rings. Thsi is needed because the C14 ratio in the atmisphere has not been perfectly constant over millenia time scales. There is a "correction" calibration for carbon dating based on the entirely accurate tree ring data. I think this would naturally catch even this rapid variation. Would be worth an expert on this letting us know if there is a particular feature in the calibration data at this time, as one would expect.

Carbon dating assumes a constant rate of radioactive decay for Carbon-14 throughout time. Has it been proved or can it be proved that the decay rate stays constant?

@Thumani #47: Carbon dating, itself, only requires a constant decay rate of 14C for the past 50,000 years or so (i.e., 9-10 half lives).

Other, longer term dating methods, such as K/Ar, U/Th, U/Pb, Pb/Pb, and many, many, many more, require that the decay rates for the many different nuclides involves have been constant for up to ~4.6 billion years.

Nuclear half lives are not magical numbers which could be the same or different arbitrarily, at the whim of whatever malevolent magical sky creature you want to invent. They are calculable consequences of the detailed structure of the various nuclei involved, and depend on universal constants, such as the strength of the electromagnetic force (a.k.a. the fine structure constant), the mass of the nucleons (proton and neutron), the masses of light mesons, and so forth.

If you want to try and force some half-life to be different than it is, in order to fit your magic sky-creature hypothesis, that will have testable and measurable consequences on many facets of nuclear structure in many different elements. Not only would those consequences be visible today, they would also be visible astronomically in the form of X-ray and gamma ray line differences, light curve differences from post-supernova nuclear decays, and so on.

So yes, the hypothesis of time varying decay rates has been well tested, and found to be false.

@Michael Kelsey #48

Speaking of malevolent sky creatures that alter nuclear half lives, whatever happened to the research showing solar activity was altering nuclear decay rates?

@47 and @48: if decay rates were significantly faster in the last few thousand years (which is what YECism would need), the whole earth would've been pocketed with nuclear explosions from natural uranium deposits going critical, a la Oklo. We would see their remains. We would detect their presence in Uranium ores with different isotopic ratios. Not to mention the rather dramatic effect such things would've had on recorded human history.
So no, decay rates were not significantly faster in the past, and we know this because a change in decay rate would not merely affect something as esoteric as radiocarbon dating, it would affect loads of other things too.

Will Quantum Fusion Save the Day?

sastyk — Mon, 30 Apr 2012 06:29:28 +0000

Will Quantum Fusion Save the Day?

The Astrophysicist, when he has time, will have something to say about his reading of the physics of the material Tom Whipple sums up.

This situation however seems to be changing following a lengthy interview with a fellow out in Berkeley, California by the name of Robert Godes of Brillouin Energy. He has been working in this field for the last ten years and says that he not only has a reliable heat-producing device, but also understands the physics behind it - which he calls the Quantum Fusion Hypothesis. He says that this theory of just how low-energy nuclear reactions work has allowed the development of a device which produces heat immediately and reliably. Most interestingly, Godes says he has shared his insights with scientists at the Los Alamos Nuclear Laboratories and SRI International, one of the leading US laboratories investigating the phenomenon. He says that both have verified that his theory does indeed work and that they can now produce heat from hydrogen every time they try.

Godes' hypothesis is interesting for those with even a smattering of physics in their background. First of all, he holds that the heat which is coming from infusing hydrogen into nickel or palladium is not coming from "cold fusion" in the classic sense of the term. It is not a deuterium fusing with deuterium reaction as takes place in the sun or H-bombs and which requires extremely high energies.

What seems to be happening in this new kind of fusion is that when hydrogen is "loaded" into nickel or palladium and subjected to the proper kind of an electromagnetic pulse, the hydrogen nucleus which is a positively charged proton acquires an electron which turns it into a low energy free neutron. Now a low energy free neutron is something very nice to have for it quickly combines with other protons to form deuterium, tritium and finally quadrium. The quadrium only lasts for an instant before undergoing a process called beta decay turning it into helium. This is where Einstein and E = MC2 comes in. The beta decay of quadrium results in a loss of mass which is turned into heat. If all this pans out as claimed, it could be one of the most important secrets of nature that has ever been discovered, for our energy problems are over.

Without the flow caliormetry, it is pretty hard to say whether there's anything under the smoke and mirrors - and who knows, there may be. At this particular juncture, as I personally understand it (not that my understanding is worth much), atomic mass remains constant when the conditions for changing protons to neutrons exists and decay energy is always smaller, but I'm certainly not the person to evaluate these results.

That said I'm inclined to skepticism - hang around energy issues long enough and you find lots of people saying they can contravene the laws of physics, or invent new ones. What makes this even worthy of consideration is that it comes from Tom Whipple, who is incredibly smart and knows energy issues really well. Still, Whipple seems to be going out of his way to overstate things, perhaps anticipating skepticism.

Eric's rather dry comment in his first reaction to Whipple's mention that it is "not yet a theory" was "Ummm...yes, you could say it is definitely not yet a theory." In fact, it isn't even in the ballpark of a theory - it is one person's hypothesis with data that has not been released, no peer reviewed papers on the subject whatsoever, in an application where he is attempting to find commercial funding. No, definitely not a scientific theory, or even in that ballpark. Which doesn't mean it won't become one someday.

I admit, though, I find myself thinking of Richard Feynman's comments on perpetual motion machines. This is not the same thing, of course, but it is a useful cautionary tale to remember:

Mr. Papp talked about how the motor worked, using vague and complicated phrases about radiation, atoms, different levels of energy, quanta, and this and that, all of which made no sense whatsoever, and would never work.

But the rest of what he said was important, for every fraud has to have the right characteristics: Mr. Papp explained that he had tried to sell his engine to the big automobile companies, but they wouldn't buy it because they were afraid it would put all the big oil companies out of business.

So there was obviously a conspiracy working against Mr. Papp's marvelous new engine. Then there was a reference to the magazine articles, and an announcement that in a few days the engine was going to be sent to the Stanford Research Laboratory for validation. This proved, of course, that the engine was real. There was also an invitation to prospective investors to get in on this great opportunity to make large amounts of money, because it was very powerful. And there was a certain danger!

There were quite a few wires running from the engine down to where Mr. Papp and the spectators were standing, into a set of instruments used for measurement; these included a variac, a variable transformer with a dial which could put out different voltages. The instruments were, in turn, connected by a cord to an electrical outlet in the side of the building. So it was pretty obvious where the power supply was.

The engine started to go around, and there was a bit of disappointment: the propeller of the fan went around quietly without the noise of an ordinary engine with powerful explosions in the cylinders, and everything- it looked very much like an electric motor.

Mr. Papp pulled the plug from the wall, and the fan propeller continued to turn. 'You see, this cord has nothing to do with the engine; it's only supplying power to the instruments,' he said. Well, that was easy. He's got a storage battery inside the engine. 'Do you mind if I hold the plug?' I asked? 'Not at all,' replied Mr. Papp, and he handed it to me.

It wasn't very long before he asked me to give me back the plug. 'I'd like to hold it a little longer,' I said, figuring that if I stalled around enough, the damn thing would stop.

Pretty soon Mr. Papp was frantic, so I (Richard Feynman) gave him back the plug and he plugged it back into the wall. A few moments later there was a big explosion:

I'm not claiming this is a scam at all, or that if it is, it is an intentional scam like the one above. What I would say is that there is a reason why most devices that seem unlikely are, and skepticism is the appropriate human response. We have yet to see a high-EROEI device that didn't come with significant unintended consequences - if this was one, it would be the VERY FIRST in human history.

While I'm going to wait for the astrophysicist to comment on the physics, I do think I might add something is with the hyperbolic bits of this essay, such as when Whipple says "our energy problems are over!" Because even if this were true, the above statement represents a non-sequitur in its most literal sense - something that does not follow from the previous statement. I don't blame Whipple for going there, but because so many people do, I think it is worth unpacking why this is not necessarily true.

So let us imagine that in fact, such a limitless source of energy does exist. Does it actually solve all our energy problems? Because this is a real and interesting and important question - and one many people believe to be the case. In fact, I would argue that the reason we need to talk about this is that the assumption that something being possible solves the problem is incredibly pervasive even among well educated people who ought to know better.

Last year I had the pleasure of spending an hour talking with (some might say grilling ;-)) my Congressman, Paul Tonko, about energy and fuel issues. At one point in our rather lively discussion, Tonko talked about ethanol and its returns. I argued that he was overstating the returns - and realized shortly that he was conflating cellulosic and algae ethanol with corn ethanol production - and speaking about AS THOUGH those latter two things were already real and widely available. When I called him on that, Tonko agreed that neither one of those were ready for prime time, but rejected the idea we should speak only about the technology as it stands now, because, of course, the fact that we know we can make ethanol on a very small scale from these things means it will inevitably become a near-term factor. In fact, it is nothing of the sort - neither one is fully ready for prime time or at all cost competetive, so when we speak about ethanol as an energy source RIGHT NOW we are talking almost entirely about food (Corn, mostly in the US) going to produce gas, and that's so far neither scalable or without consequences.

I mention this not to pick on Paul Tonko who I think is awfully smart and an extremely congressman, but to point out how universally we believe that technology IN AND OF ITSELF is right there to save us simply by existing. That is, because things exist, we tend to assume that economic, social and technological barriers will magically be overcome. And yet, that's not true - we've known, for example, how to use hydrogen as an energy storage mechanism for a very, very long time, and yet the once much-touted "hydrogen economy" has never become even remotely real, because of technical and economic issues. Technical feasibility, despite our desires and assumptions, does not translate into "make it so." We often assume it does, but that isn't factually correct, as I wrote in this essay:

One of the hardest concepts for many Americans to absorb is this - that technical feasibility rests on a complex bed of other feasibilities and never stands alone. Thus, simply observing that it is technically possible to, say, create zero impact cities or to run our cars on corn waste does not usefully tell us whether we are going to do so or not. This historical reality stands in stark contrast to the perceptions that many of us have, which is that technology operates as a kind of vending machine into which one puts quarters and gets inevitable results.

For example, it has been technically possible to eliminate most causes of death in childhood for the world's poor for thirty to forty years, and periodically the UN and other agencies explain how this might technically come about. But without other base elements of feasibility - a real commitment to saving impoverished children worldwide - it turns out that it is technically infeasible.

The same, of course, is true of addressing climate change and peak energy - it was wholly technically feasible for us to begin transitioning to a renewable energy economy in the 1970s, and had we done so, both issues would be vastly more manageable and comparatively minor concerns. It is still technically feasible, although enormously difficult, that we could drop industrial emissions dramatically or reduce our fossil fuel consumption. It is not, however, economically or politically feasible that we do so, as evidenced by the fact that we're not, despite emergent consequences.

We are in the habit of forgetting the basis of will, energy and money that technical capacities rest on - we assume that because an outcome is desirable, it is therefore likely. But low infant mortality is eminently desirable, something I suspect most of us can agree on - and there are no major technical barriers.

I'm willing to concede that if this does work as described, we are probably looking at an incredibly high EROEI. If it turns out as claimed that heat and water are the only outputs (and not any of those neutrons or beta radiation), that the casing materials are not consumed and it turns out to be fairly easy to build them, the research gets published, verified and duplicated rapidly and production gets started on multiple fronts, and we have time and resources to get the kinks out, find the funding, run the demo plants, see how the long term unintended consequences if any shake out, the retrofit our entire society, I can totally hang up my hat on peak oil and turn to writing about other stuff - I'm assuming I'll write cute stories about my kids and post pictures of cats like most folks on the web. And hey, that'll give me loads more time for my garden.

By any chance did you notice the chain of things that are necessary to getting from an article about a hypothesis on which we have no data to "hey, I'm going to put some shrimp on the quantum fusion-powered barbie tonight!" There were quite a few of them, weren't there? Now it is taken as a given in our larger culture that those are trivialities can be erased by something we call "innovation" and "market forces" - which we really translate as "our ability to make all this stuff happen." Unfortunately, when we look back at the history of technology, what we find is that innovation alone, market forces alone don't work all that well in many cases. Sometimes they do - the amazing cases are pretty easy to spot. But neither is it that difficult to spot examples of things that we could technically do, that would have been an awesomely great idea, but that didn't happen, despite ingenuity and resources.

Even if all of the ducks that need to be in a row to make this happen are there, we need to remember two other things. The first one is that solving our energy problems may not solve our other fundamental problems. I know Tom Whipple understands the distinction, but it would be an easy mistake for a reader to translate "energy problems" to mean "problems." For example, if climate is as sensitive as some scientists suggest, the time frame for development of this technology may not be sufficient to have it come online before we've crossed critical climate tipping points.

Now having all the energy we want and no limits on its use would certainly help us mitigate an extreme climate disaster, but there's really no evidence that it would be ENOUGH.

It would be great if, for example, we could run air-conditioners 24/7 without worrying for billions of people as the planet heat up, or afford to medivac in people with free electric emergency vehicles, but a planet eating up 1/5 or more of its economic resources annually in disaster mitigation is still going to be a planet in crisis. The same is true with our agricultural and other ecological crises - more energy can help in some measure. But it would be a huge mistake to believe that energy alone is sufficient. Add in a considerable time frame to get from 0-60, and it behooves us to be cautious even if we think this would work. Collapsed societies historically have a hard time bringing major new technologies on line - this resource would have to come into play at the right moment - and the last possible moment to do so get closer all the time.

In fact, most collapsed societies have collapsed WITH the means to avoid collapse within their technical grasp, as Jared Diamond so eloquently describes in _Collapse_ - most of them could have planted more trees, or not drawn down their resources so rapidly. They had all the tools in place to prevent a disaster - and didn't. One can easily make a compelling case that we too have needed no technologies that we did not have at any point in this process - had we started shifting to renewable energies earlier in the game, as was proposed in the 1970s, we too could avoid crisis. Technologies themselves are not saviors. This is hard to remember, but critical - technology is great, but it always has unintended consequences, and in the end, usually doesn't make or break societies.

It would be wise to remember this bit from the 30 year Update of The Limits to Growth:

"The most common criticisms of the original World3 model were that it underestimated the power of technology and that it did not represent adequately the adaptive resilience of the free market. It is true that we did not include in the original World3 model technological progress at rates that would automatically solve all problems associated with exponential growth in the human ecological footprint....[But] in several scenarios we test accelerated technological advance and possible future technical leaps beyond these 'normal' improvements. What if materials are almost entirely recycled? What if land yield doubles again and yet again? What if emissions are reduced at 4% per year over the coming century?

Even with such assumptions, the model world tends to overshoot its limits. Even with the most effective technologies and the greatest economic resilience that we believe is possible, if these are the only changes, the model tends to generate scenarios of collapse." (TLTG:TTYU p. 204-5)

Whether this discovery turns out to be true or false, the question of whether it or anything else can "save" us in the sense most people would like to be saved - let us go on as we have been - is dependent on a number of variables that go beyond "can we build it." At a minimum, it seems wise not to put too many eggs in any basket, for it is perfectly possible to imagine us with a solution at our fingertips that is still out of our functional reach.

Sharon

sastyk Mon, 04/30/2012 - 02:29

Tags

Nuclear Power and the Problem of the Future

sastyk — Mon, 23 Apr 2012 08:00:20 +0000

Nuclear Power and the Problem of the Future

Note, I'm horrified to realize I inadvertantly left out the link to Rhagavan's piece - SO SORRY about that, and please do click through - it is well worth a full read.

Barath Rhagavan has a superb article about the conversion of many climate scientists to support of nuclear power and the reasons this is problematic. These match my own major objections to nuclear as a response. As serious as the environmental impact of failure is, that's not the single biggest issue I see. Even if I thought the siting would avoid any future climate related disasters (I don't), the main issue is the problem of economics and depletion in the longer term. Nuclear is simply, as Rhagavan puts it, not a technology that fails well:

Specifically, three things strike me as the major reasons to avoid nuclear:

Limits to growth. In a (permanently?) declining global economy, the resources (mostly financial, though military resources are important for nuclear safety) to keep plants well maintained are going to be scarce. Nicole Foss said it well---that after studying nuclear safety in Eastern Europe she concluded that nuclear power is incompatible with hard times. It's these hard times that invalidate assumptions about the safety procedures and other risk modeling, for example, that can cause unforeseen cascading accidents.

Waste storage. I think it is possible for us to store waste for the short term. It's the longer term that is a bit more doubtful, and regardless of the duration it's an expensive undertaking. The 2010 documentary Into Eternity on Finland's waste storage plans reminded me of a few things: a) Finland is a small country, and yet the scale of the waste site is huge, b) planning for the 100 years it'll take to finish the waste site is hard enough (will there be the money needed to complete it? how is it possible to plan for 100 years when we can't plan beyond the next congressional election?) let alone the hundreds of thousands of years it needs to survive intact, and c) they've been working on this for a decade already, while no other country has even the beginnings of a solution. (The documentary was a bit sad: Finland has assembled a number of expert, sincere people trying to solve a problem that you sense they realize cannot be solved.)

Scale. Nuclear isn't particularly cheap when you compare it to alternatives (though cost estimates vary wildly) and is difficult to scale up quickly. In my calculations on alternative energy several months back, I found David MacKay's estimate that the peak rate of nuclear power plant construction ever achieved was 30GW of nameplate capacity per year, globally. At that rate we'd only build 0.6TW in 20 years, a drop in the bucket compared to the ~16TW of primary energy we consume globally today.

As I've said many times, we'd find a justification for shovelling live baby harp seals into furnaces if necessary, so I don't have the slightest doubt we are going to build some nuclear plants. Or at least try to. In the end, opposition to nuclear will vanish as energy becomes scarcer and more expensive - but probably too late to do a large scale build out, if it isn't already.

One of my worries is that a half-built nuclear plant is a long way from being an asset on the landscape - and one of the consequences of economic collapse is a lot of half-built things. Still, I put this with drilling in ANWAR - it will happen. But fundamentally, it can't happen fast enough to "save" us from our collective crisis. And it isn't a solution.

Ultimately, all those conversions come from a simple underlying premise - we won't cut our energy usage. They are probably right, in terms of voluntary response. Our energy usage will get cut, however, by necessity, if not desire. Sadly, it probably won't be enough to avoid unchecked climate change - but neither will the number of nuclear plants we actually build before the depletion curve bangs into us.

Sharon

sastyk Mon, 04/23/2012 - 04:00

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"Incompatible with hard times" is so well put -- especially for all those open air waste pools, which need expensive and expert maintenance for decades. Starvation Ridge is about this, or anyways about the consequences. How do we ever get to "post"-apocalytic if we shackle ourselves to apocalyptic and drag it along with us?

Not a technology that fails well? What a despicable lie.

Tepco's photojournal shows that not a blade of grass was harmed by radiation at FD1: http://photo.tepco.co.jp/en/index-e.html .

Now the Japanese government is earning millions of additional dollars per day on LNG imports. Let's hope the citizens can soon get it to stop lying about their opinions, and turn the reactors back on.

Wow. if it were my blog, #2 would be deleted; I see NO value in allowing astroturf. Any readers actually interested in unfiltered truth from Japan should check out my blog.

Anyway- Sharon, my #1 reason why nuclear is stupid is- it relies on HUMAN judgements and actions to keep it safe. And the things are so complex each one has 50,000 individual decisions involved in constructing it; and 1,000 per year in maintaining it.

And 98% of those must be 98% correct- or- meltdown. (They do build in that 2% "safety factor".

Engineers tend to believe in perfectibility. As an evolutionist- I believe in evolution; which includes lots and lots of death. Humans, over time, will ALWAYS eventually make a bad decision; and in the case of nuclear power- the consequences are unacceptable. Most recently from Japan; even the government is admitting that some towns around Fukushima will still be uninhabitable 10 years down the road; not matter how much clean up is done. And those are the wild-eyed optimists.

www3.nhk.or.jp/daily/english/20120423_04.html

Thanks Sharon!

The good news, if there is any, about leaving half-built nuclear plants on the landscape is that fuel is only loaded at the very end, so if nothing else they'll be sites with lots of high-quality metals and equipment for stripping down and re-use.

Mr. Graham Cowan, you have been just about everywhere over the Internet over the years peddling your nuclear views.

Just how much do you get paid for the continuous disinformation campaign?

The funny thing is, I don't think you *do* actually get paid to perform the astroturfing. No, I picture you locked into your engineering laboratory, surrounded by fellow techies, year after year, funded by who, I don't know, hoping that we'll all eventually be surrounded by copious numbers of nuclear plants, all the better to make the electricity to fund your boron car fuel ideas, all while belittling and lamenting the billions of uninformed Luddites you folks are otherwise stuck on this planet with.

Greenpa has it. Engineers (I am a former EE) put *way* too much credence into the idea that technology, especially complex technological systems, will perform with near perfection. But, of course, it's the people working the technology that fail as we've seen time and time again. Please do yourself a favor and finally open your eyes to this reality of the human world as it really is.

I want to love nuclear, but the facts are that we have hundreds of plants world wide, combined with thousands of tons of spent fuel, sitting mainly in temporary storage, that are Chernobyl times 10 waiting to release amazing amounts of radiation. Even the prosperous, well-off country of Japan cannot deal with the repercussions of their serious, nuclear plant failure. It could get far worse if the main spent fuel pool fails as said possibility has been recently reported. The idea that Iran or many other less prosperous, less stable societies can properly safeguard nuclear power facilities for decades, let alone years, is preposterous. In fact, it is indeed an idea that only can exist inside the minds of scientists and engineers that have spent too much of their time in a research laboratory, away from the realities that comprise the rest of human existence.

I'm sorry, but your complex technological utopia, fueled by nuclear and boron technologies just isn't going to happen, now, or frankly ever. Humanity just doesn't have what it takes, in the aggregate, to support such a level of complexity.

Indeed, what we've seen over the past 5 to 10 years is a civilization failing to maintain the complexity it already has created.

As an Engineer, who has actually worked on nuclear plants, I can tell you that Greenpa @3 is not correct. Lots of errors can be made and a nuclear plant will still be safe. Far more than the 2% he allows. Although it is true that nuclear does not fail well.

We Engineers believe in redundant safety systems, to cope with the problem of putting people in the loop.

Despite all that, nuclear is not the solution to our problems, for the good and cogent reasons quoted above. It is too slow to build and costs way too much to be economical except in very high energy density settings, where you can build a huge plant and get some economies of scale.

Waste storage is a solved problem, if we are willing to pay what it would cost to be safe (search for Synroc; an Australian solution that I had a very small part in back in the '80s).

But again, the problem is cost. And don't even ask about the insurance underwriting issues...

Robert- I knew it was more than 2%; and assumed (foolishly perhaps) that most readers here at Science blogs would recognize "poetic license" when they saw it. Mea culpa. : - ) Do you happen to know what the actual safety factors tend to be? My taking poetic license there was based on the attempt to communicate to readers "reality"; rather than "engineer religious faith".

My father was a Navy Civil Engineer, and later professor; and worked at multiple nuclear facilities- we NEVER were able to agree about it; and learned to just avoid the topic.

This true observation/conversation with him will illustrate to most people the failure in the engineer's belief system.

Driving past the local High School, my father and I observed them repairing the roof of the gymnasium; for the 4th time. I made an offhand comment about how idiotic it had been to choose to build a flat roof in the first place, under any circumstances, in Minnesota. My father responded quite angrily (it always pissed him off when I offered opinions on engineering - never mind that I now hold international patents in metallurgy...) "Don't be an ass; there's absolutely nothing wrong with a flat roof here- you just have to build it correctly."

As we drove- watching them fix it- again. I didn't bother to point out - "Yes; but they DIDN'T build it correctly; did they? And; historically; what percentage of similar flat roofs in this climate ARE built to adequate standards?" - because it would just piss him off further.

He could sit there- SEE the failure- and still believe, and argue- no, flat roofs are a good technology.

No; they're not- not in Minnesota- because they're always built by PEOPLE, you know.

And; my father was unquestionably a top competent engineer. If you ever land at the Honolulu airport- he built it (ok, he was one of the chief design and construction engineers). But- he never had any real comprehension of "human frailty" - it just wasn't allowed, in his world.

But that's just it Robert, we *don't* want to pay for the storage. That's why world wide we have hundreds of semi-temporary spent fuel rod pools, just sitting there, requiring active cooling for many years on end, pools that burn their capping water off in a matter of a week or so, when active cooling fails.

In short, waste *isn't* a solved problem at all. In fact, as we've seen in Japan, it's at the heart of the matter, given the problem they've had with their pools.

What happens to those spent fuel pools when a society suffers hard times, never mind what happens to the main reactor vessel, even if it is shut down? It can't just sit there for years while economic storms, revolutions and counter revolutions swirl around, outside the gate.

We engineers can say over and over, that the technology is redundant, that solutions exist, but if said solutions for whatever reason, are not attractive enough to be utilized 100 percent, by the society at large, then, especially in the case of nuclear, it fails.

There will be more Chernobyls, Three Mile Islands, and especially Fukushimas. You and I can count on them. There are many plants similar to the Fukushima design (I'm talking about the pools as well, not just the main reactor, circulation design, vessel, and reactor containment structure), that require months and years of active cooling to the pools....counting on uninterrupted off-site power availability all that time. (No power plant keeps the months and years of backup diesel fuel on hand that cooling systems require in the event of a bad earthquake, tsunami, or other natural or man-made months-long grid outage, exactly the kind of grid outage that is quite possible especially in the less-developed world now turning to nuclear.

It is quite obvious to me that, unless the world gets spent fuel broken down, repackaged, and quickly stored in ways that allow passive cooling in removed, remote, isolated locations, there will be lots more pool accidents, and probably much worse than the one at Fukushima and this world ISN'T going to do this for the same reason this world hasn't done a lot of other things it should do - it can put it off until tomorrow - and with very predictable consequences.

When engineers argue against human nature as we are often likely to do, engineers lose every time, and this applies to much more than the nuclear power situation.

EXACTLY what Greenpa #7 just said, while I was typing.

The belief system for way too many engineers simply fails to understand the human situation. That is, engineers do understand that humanity has an inability to understand and execute technological systems, but all too many engineers think that if only enough science and technology would be *forced* onto their fellow, un-technological brethren, all would eventually turn out okay.

As a former engineer, Greenpa, I'm not surprised that he used to get upset by conversations such as you mentioned.

As somebody who works in nuclear energy but is not a true believer, my view of it is the same as any energy source -- we'll make better decisions about our energy future if we first understand our energy present. So I wrote a book detailing life at a US nuclear plant both before and during an "unfortunate event". The intent is not to convince eveyone that nuclear is perfectly safe or terribly dangerous, but rather to give folks a realistic look at the process. (Obviously, I don't think it's horrible, but nothing's perfect either.) What decisions we make going forward depend on a lot of things beyond our imperfect technology and pure economics.

"Rad Decision: A Novel of Nuclear Power" is avaiable free online (no sponsors or ads) - just Google the title. There's also a paperback at Amazon for traditionalists. There are many reader reviews of Rad Decision at the homepage. Little media attention though - they're too busy, I guess.

I also commend the author of the post on mentioning conservation. The cleanest, cheapest, safest energy out there is the stuff we don't use.

For those of you who want to see what Sharon's talking about looks like, come visit us in Washington state. The state utility (WPPS, pronounced "Whoops") decided to build some nuclear power plants a few decades back. They went broke, and the unfinished concrete plants have been sitting and mouldering ever since. Fortunately that happened well before they were ready to take delivery of fuel.

So, yeah, we'll try it; perhaps even with the thorium technology the nuclear power boosters have been talking about for the last 50 years. We're a lot broker now, as a nation, than we were 30 years ago; so with any luck, the results will be similar to the WPPS experience.

Glenn
Marrowstone Island

"When engineers argue against human nature as we are often likely to do, engineers lose every time, and this applies to much more than the nuclear power situation."

Or to put that another way...

Whenever engineers are 100% sure they have designed and built something that is completely idiot proof, nature always one ups them by coming up with a new and much improved idiot!

It should be noted that after a couple of years one can move to the dry cask storage method. It should be noted that the heat produced by spent fuel decays with time. Of course if one worked at it with 1 ton of fuel producing 10kw after a year you could do something like the thermocouple heat generators on deep space probes and get some electricity from it. The Dry cask method is probably good in the 100 year time frame at least depending on where the storage place is.

Lyle,

That's pretty much what I was getting at...dry cask storage in a deep, secure place. It's not perfect, nor do I want to gloss things over for the nuclear power industry, but almost anything is better than the hundreds of cooling pools sitting around, most in highly populated areas, and/or near lots of water bodies, the pools just waiting to run dry for one failure reason or another.

Here's more "good" news about Fukushima too... The web site is a bit extremist, but if even half of this is true (and probably is, given the citations contained within), then we are in serious trouble: "http://endthelie.com/2012/04/21/fukushima-is-falling-apart-are-you-read…"

FWIW, here's the URL for the original post:

contraposition.org/blog/2012/04/21/the-wisdom-of-deathbed-conversion/

Long delay, thanks to the time difference from here to most of you.

Greenpa @7, sorry, I have been too long out of the industry to know what factor of safety the US regulators require. It varies across the world, of course. Mostly we designed to cope with ten times the expected output, and at least five times the calculated worst case scenario. But like I said, that varies, which is a lot of the problem.

I'm afraid I don't understand your father. Certainly flat roofs are fine, and could be built in Minnesota, I suppose. But engineering is supposed to be about efficient solutions, which a flat roof prone to snow loads is most certainly not. That attitude just doesn't make sense to me, personally or professionally. Maybe I was trained differently...

Stephen B. @8, yes that was my point. The barriers to the widespread use of nuclear power are not technical, but economic. We are never going to be prepared to pay what it would cost to have safe nuclear power, and most especially waste storage. And again, why build the nuclear flat roof when we have better, safer and more efficient solutions already (efficient in the overall sense here).

I think this argument needs to be pushed more. The proponents of nuclear power often that the next generation of reactors will be safe. But in reality, we could make our existing technology safe enough, if we spent enough. Which we will continue to be unwilling, perhaps unable to do.

I can do no better than cite the Amory Lovins concept of the negawatt. The cheapest, cleanest power is the power you don't have to generate. Let's start there, with the lowest hanging fruit. When we have all we can from efficiency and reduction, then we can look for other sources of power.

Of course, the other objection to nuclear power is that it is just too slow. There is no way that we could replace fossil fuels with nuclear quickly enough to avoid serious climate change. Even with Gen 4 technology, which so far is as proven as carbon capture and storage or unicorn powered treadmills.

Barath, so, so sorry for omitting the link - I'm not sure what's wrong with my brain these days (probably the night waking for kidding season). You are very gracious about it, but I'm horrified that I left it out!

Sharon

I agree that it is a good thing that the fuel is loaded at the end (and did know that), but the larger point is that generally speaking, when facing actual collapse, you want solutions that work EVEN if there is a systems failure. For example, distributed solar or wind systems that get partially up often can provide some power, or could be made to. Nuclear is problematic because of the enormous frontloading of fossil fuels and money that goes into it - basically all the carbon and cash get put up front, and even a fuel-less nuclear plant, as Glenn points out, is simply not a landscape asset and is hard to repurpose.

Sharon

Thanks Sharon, and no problem.

Agreed about the uselessness of half-built plants. I think Greer expects the same thing---IIRC his story Star's Reach has many half-built nuclear plants dotting the landscape, and one of the issues is that people don't know which ones are safe and which ones aren't (i.e. with fuel or without fuel), so they mostly stay away and that investment is wasted.

There's also a huge cross-generational ethical issue about projects (or systems, or items) whose benefits are short-lived and costs are long-lasting.

Included in that category are lingering CO2 from fossil fuel consumption, nuclear decommissioning and waste timescales well in excess of a plant's productive life.

"nuclear power is incompatible with hard times"Â£

Indeed, if you build enough of it. The correlation between national wealth and energy production is to close to honestly dispute.

If you knew anything about the subject you would know that reactor waste has a relatively short half live (otherwise it coulfn't be so radioactive) & is thus down to safe levels within decades.

There is no objective reason why building reactors cannot be scaled - ir mass produced. The reason it isn't done is entirely politicis. You might as well say that because cars were handmade in 1900 it is impossible for Mr Ford's newfangled mas production line to work & thus for America to have more than a few hundred cars.

Neil,

"If you knew anything at all"... you'd know that if a spent fuel rod pool loses its active cooling for anything for a few days to a week or so, it will boil dry LONG BEFORE decades have passed by, leading to wildly radioactive fires.

You obviously didn't read much of the comment thread above where a lot of us agreed that things "could" be done better, except that human nature gets in the way (the thing you disparagingly call "politics.")

Argue all you want, but massive-scale nuclear power will not work as humans, on a large and long scale, do not have the ability to adequately follow through on the maintenance required to protect hundreds upon hundreds of nuclear plants and spent fuel pools (all with fuel FAR younger than "decades."

We have done so for over 60 years so far.

If your claims about it being impossible for human beings to work together were true Mr Ford would not have been able to produce all these cars (or Al Gore the internet ;-) ).

You first paragraph majes sense only if no unattened, underground storage of waste has ever existed. That, of course, is as false as virtually everyhting said by any of the Luddites calling themselves "environmentalists". Or perhaps you would care to produce some evidence that all the ones existing are actually imaginary.