dark energy
esiegel | May 15, 2016“If I can't make it through one door, I'll go through another door - or I'll make a door. Something terrific will come no matter how dark the present.” -Rabindranath Tagore
Time continues marching on here at Starts With A Bang, just as it does everywhere. My Patreon supporters have stepped up their game, and we're just $21 shy of unlocking our next goal! There are two great new items this week I'd love to share with you: first, our newest Podcast on dark energy and the fate of the Universe,
and second, a video whose script I helped write (with a bonus coming up) for Kurzgesagt - In a…
esiegel | May 13, 2016"It's everywhere, really. It's between the galaxies. It is in this room. We believe that everywhere that you have space, empty space, that you cannot avoid having some of this dark energy." -Adam Riess
Back in the 1990s, scientists were quite surprised to find that when they measured the brightness and redshifts of distant supernovae, they appeared fainter than one would expect, leading us to conclude that the Universe was expanding at an accelerating rate to push them farther away. But a 2015 study put forth a possibility that many scientists dreaded: that perhaps these distant supernovae…
esiegel | May 12, 2016“Even if I stumble on to the absolute truth of any aspect of the universe, I will not realise my luck and instead will spend my life trying to find flaws in this understanding – such is the role of a scientist.” -Brian Schmidt
Imagine you had arbitrarily great technology, limitless energy, and the ability to accelerate as close to the speed of light for as long as you wanted. Would you be able to reach the most distant galaxies, the leftover glow from the Big Bang or anything beyond the limit of what we can see today?
Image credit: NASA, ESA, and Z. Levay (STScI). The GOODS-North survey,…
esiegel | April 26, 2016"The world is the great gymnasium where we come to make ourselves strong." -Swami Vivekananda
But what does it truly mean to be strong? We have four fundamental forces in the Universe: the strong, electromagnetic, weak and gravitational forces. You might think that, by virtue of its name, the strong force is the strongest one. And you'd be right, from a particular point of view: at the smallest distance scales, 10^-16 meters and below, no other force can overpower it.
Image credit: Sloan Digital Sky Survey, of IC 1101, the largest known individual galaxy in the Universe.
But under the…
esiegel | April 12, 2016"That’s all regular matter, just five percent. A quarter is “dark matter,” which is invisible and detectable only by gravitational pull, and a whopping 70 percent of the universe is made up of “dark energy,” described as a cosmic antigravity, as yet totally unknowable. It’s basically all mystery out there - all of it, with just this one sliver of knowable, livable, finite light and life." -Summer Brennan
The Universe could have had any number of fates, even given that it started out with a hot Big Bang. Gravitation could have overcome the initial expansion, eventually causing a recollapse and…
esiegel | March 18, 2016"Quintessence is a dynamic, time-evolving, and spatially dependent form of energy with negative pressure sufficient to drive the accelerating expansion [...] Whereas the cosmological constant is a very specific form of energy." -Robert Caldwell, inventor of the Big Rip scenario
Our Universe began with a period of cosmic inflation: where energy intrinsic to space itself caused an extremely rapid, exponential expansion. This stretched the Universe flat, gave it the same properties, temperature and spectrum of fluctuations everywhere, and then gave rise to the hot Big Bang. And our Universe is…
esiegel | March 2, 2016"If you take everything we know... it only adds up to 5% of the Universe." -Katie Freese
One of the greatest advances of the 20th century was the discovery of the vast nature of the cosmos: that it was filled with billions of galaxies, each containing billions of stars, and that it extended in all directions for at least tens of billions of light years. Yet when we look out at the full gamut of all there is, the stuff that's normal matter -- made of the same protons, neutrons and electrons that we are -- can account for no more than 5% of the total energy in the Universe.
Image credit: NASA…
esiegel | February 24, 2016"Even if I stumble on to the absolute truth of any aspect of the universe, I will not realise my luck and instead will spend my life trying to find flaws in this understanding - such is the role of a scientist." -Brian Schmidt
One of the biggest surprises in our understanding of the Universe came at the end of the 20th century, when we discovered that the Universe wasn't just expanding, but that the expansion was accelerating. That means the fate of our Universe is a cold, lonely and isolated one, but it's a fate that we wouldn't have uncovered if we were born when the Universe was just half…
esiegel | January 1, 2016"Gamow was fantastic in his ideas. He was right, he was wrong. More often wrong than right. Always interesting; … and when his idea was not wrong it was not only right, it was new." -Edward Teller
Considering what we know about our Universe today, it's hard to believe that just a century ago, Einstein's General Relativity was very much untested and uncertain, and we hadn't even realized that anything at all lie outside our own Milky Way. But over the past ten decades, ten great discoveries have taken place to give us the Universe we understand today.
Image credit: Adam Block/Mount Lemmon…
esiegel | November 18, 2015"There are still so many questions to answer. When you look at any part of the universe, you have to feel humbled." -Saul Perlmutter
Discovered in 1998 from the observation of distant supernovae, dark energy determines the eventual fate of the Universe, leading to a "Big Freeze" scenario, where all the galaxies, groups and clusters that are presently gravitationally unbound from one another will eventually recede away until they're unreachable.
Image credit: NASA & ESA, via http://www.spacetelescope.org/images/opo9919k/.
But if dark energy truly permeates all of space as a cosmological…
esiegel | September 25, 2015“What is wild cannot be bought or sold, borrowed or copied. It is. Unmistakeable, unforgettable, unshamable, elemental as earth and ice, water, fire and air, a quintessence, pure spirit, resolving into no constituents.” -Jay Griffiths
When you think about the frontiers of scientific knowledge -- on the border between what's known and what's unknown -- you have the phenomena that we know exist, yet that we can't fully explain. This includes the matter-antimatter asymmetry, the inflationary origin of our Universe, dark matter and dark energy, among others. Yet two of these, inflation and dark…
esiegel | August 14, 2015“First, you should check out my house. It’s, like, kinda lame, but way less lame than, like, your house.” -Lumpy Space Princess, Adventure Time
When you visualize our Universe today, you probably think about the great clumps of matter -- planets, stars, galaxies and clusters -- separated by huge distances. But on the largest of all scales, tens of billions of light years in diameter, any given region of the Universe is virtually indistinguishable from any other.
Image credit: ESA/Herschel/SPIRE/HerMEs, of the Lockman Hole.
But this structured Universe only came about because our Universe…
esiegel | June 7, 2015“There is no end to education. It is not that you read a book, pass an examination, and finish with education. The whole of life, from the moment you are born to the moment you die, is a process of learning.” -Jiddu Krishnamurti
If you want to learn something -- whether it's abstract or concrete, solving a problem or creating something -- that you don't already know, it often involves ridding yourself of your preconceptions of how such a thing ought to work. Often, it outright involves unlearning or overriding something you previously thought was true. Have a listen to Ray Lamontagne, as he…
esiegel | April 15, 2015“If you think this Universe is bad, you should see some of the others.” -Philip K. Dick
When it comes to measuring the expansion history of the Universe, the concept is simple enough: take something you know about an object, like a mass, a size, or a brightness, then measure what the mass, size or brightness appears to be, and suddenly, you know how far away that object has to be.
Image credit: European Space Agency, NASA, Keren Sharon (Tel-Aviv University) and Eran Ofek (CalTech).
Add in a measurement of the object's redshift, and you can figure out not only what the expansion rate of the…
esiegel | April 11, 2015“Some say the world will end in fire,
Some say in ice.
From what I’ve tasted of desire
I hold with those who favor fire.
But if it had to perish twice,
I think I know enough of hate
To say that for destruction ice
Is also great
And would suffice.” -Robert Frost
We've come to believe that we know the fate of the Universe: that dark energy will drive distant galaxies and clusters apart, leaving only the objects that are already gravitationally bound together intact.
Image credit: NASA/JPL-Caltech.
Through the use of type Ia supernovae as standard candles, we've been able to trace out the…
esiegel | January 7, 2015“People are trapped in history and history is trapped in them.” -James A. Baldwin
We've come a long way since we first started watching the night skies. Even just a century ago, we thought our Universe was governed by Newtonian gravity and consisted only of our Milky Way and the stars inside.
Image credit: SDSS.
In the past 100 years, we've come to understand that our Universe is a vast, expanding-and-cooling space that formed planets, stars, galaxies and clusters from a past that was so hot and dense we didn't even have atoms, nuclei, or stable protons! There are a myriad of questions…
esiegel | January 1, 2015“And now we welcome the new year. Full of things that have never been.” -Rainer Maria Rilke
Yes, it's true, with 2015 upon us, the new year holds a number of wonderful new things. Not only for us, but for the Universe as well!
Image credit: Stuart Rickard of After Ice, viahttp://blog.after-ice.com/stuart-rickard/.
Consider all the time that's passed, leading up to today. Consider how far we've come, from the Big Bang until right now, as "one Universe year," and now imagine, looking forward, what the next Universe year (or years) will hold.
Image credit: NASA, ESA, J. Jee (University of…
esiegel | December 19, 2014“We are incredibly heedless in the formation of our beliefs, but find ourselves filled with an illicit passion for them when anyone proposed to rob us of their companionship.” -James Harvey Robinson
The Universe seems to be full of contradictions. On one hand, everywhere we look -- in all directions and at all locations -- we find that it's full of stars, galaxies and clusters. There are regions pretty much everywhere where, in the great cosmic struggle between all the pulls and pushes, gravitation has won.
Image credit: NASA; ESA; G. Illingworth, UCO/Lick Observatory and the University of…
esiegel | December 15, 2014“Our feeblest contemplations of the Cosmos stir us — there is a tingling in the spine, a catch in the voice, a faint sensation, as if a distant memory, of falling from a height. We know we are approaching the greatest of mysteries.” -Carl Sagan
34 years ago, Carl Sagan became the first person to present -- in a format accessible to the entire world -- a synthesized story of all the most important scientific points and facts that we had learned about the cosmic story common to us all.
Image credit: NASA / GSFC, via http://cosmictimes.gsfc.nasa.gov/universemashup/archive/pages/big_bang….
No…
esiegel | December 11, 2014“Some say the world will end in fire,
Some say in ice.
From what I’ve tasted of desire
I hold with those who favor fire.
But if it had to perish twice,
I think I know enough of hate
To say that for destruction ice
Is also great
And would suffice.” -Robert Frost
Sure, it's getting colder and colder all over the northern hemisphere, as the cold season of winter approaches. But we can be fairly confident that this won't be the case forever: the Earth will tilt its northern hemisphere back towards the Sun, and warmer weather, after a few months, will ensue once again.
Image credit: Jean-Charles…