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“Science progresses best when observations force us to alter our preconceptions.” -Vera Rubin
Yesterday, we took an amazing look at a finding that looks like it rules out Dark Matter's #1 Competitor: TeVeS. But if that's true -- and the Universe must be full of dark matter -- just what exactly do we know about this mysterious substance?
Image credit: Chris Blake and Sam Moorfield, via http://www.sdss3.org/surveys/boss.php.
From how we know it's there, to how we know it's not normal matter, to what properties we can identify just from the indirect, astrophysical observations we can…
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“The discrepancy between what was expected and what has been observed has grown over the years, and we’re straining harder and harder to fill the gap.” -Jeremiah P. Ostriker
When it comes to the Universe, and the structure in it, from galaxies to groups to clusters to the grand cosmic web on the largest scales, you simply can't account for it all without dark matter.
Image credit: 2dF GRS, via http://www2.aao.gov.au/2dfgrs/Public/Survey/description.html.
But in principle, you might not need dark matter to do it; you might be able to modify the laws of gravity instead to take care of…
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“He who loves practice without theory is like the sailor who boards ship without a rudder and compass and never knows where he may cast.” -Leonardo Da Vinci
One of the great tools that theorists use in their arsenal is the reductio ad absurdum, or the notion that if you can prove that the acceptance of a scientific theory leads to an unacceptable prediction known to conflict with experiment. But there's a catch.
Image credit: University of Iowa.
You see, if it's an experiment that hasn't been rigorously performed before, you must actually perform it, no matter how ridiculous the…
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“Rest is not idleness, and to lie sometimes on the grass under trees on a summer’s day, listening to the murmur of the water, or watching the clouds float across the sky, is by no means a waste of time.” -John Lubbock
Each Messier Monday, we take a look at one of the 110 deep sky wonders that make up the Messier catalogue, each one providing a unique window into our nearby Universe and the history it holds. This week, however, rather than giving you a delight that's easily visible in the early part of the night from my (45° N) Latitude, let's celebrate cinco de Mayo by showing you one that…
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“Every moment of light and dark is a miracle.” -Walt Whitman
To those of you who regularly enjoy clear, dark skies and the wondrous sights they bring, you have not only my envy, but the envy of a great many of us who long to have the wonders of the Universe directly accessible to our eyes. As the Jayhawks sing, you might be dreaming of
Stumbling Through The Dark.
But the way our modern world works, humans tend to be clustered together in heavily light-polluted cities.
Image credit: Google Maps / Blue Marble / NASA Earth Observatory, via http://www.blue-marble.de/nightlights/2012…
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“If the world wants you, it's gonna keep on coming till it gets you. And who am I that can fix it? Who am I that can change this if the world wants it so badly? Who am I to stop the end of the world if it keeps on coming?” -Patrick Ness
It's been a wonderful and diverse week over at the main Starts With A Bang blog on Medium, and we've covered an awful lot of ground if you missed anything (or want a re-read), including:
Using up the Universe's Fuel (for Ask Ethan),
LEGOs for those with a little Curiosity (for our Weekend Diversion),
An Elliptical Rotating Wrongly, M59 (for Messier Monday),…
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“The atoms become like a moth, seeking out the region of higher laser intensity.” -Steven Chu
Sure, lasers are fascinating entities. By stimulating the right medium with the right conditions, you can induce the stimulated emission of radiation of the same exact wavelength in the same exact direction over and over again.
Image credit: Q-LINE Laser pointers, via Wikimedia Commons user Netweb01, under a c.c.-by-3.0 license.
But is there a limit to the amount of energy that can be produced by a laser? And if so, what is that limit, and might it be overcome by future technological advances, or…
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“Most estimates of the mortality risk posed by asteroid impacts put it at about the same risk as flying in a commercial airliner. However, you have to remember that this is like the entire human race riding the plane — it is one of the few risks that really could wipe us all out.” -Nathan Myhrvold
Yes, it's easy to say that even though the risks of getting killed by an asteroid strike are low, the consequences of a major asteroid strike are simply too high for us to not address this threat.
Image credit: Don Davis.
But is that really true? This isn't pontificating; this is…
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“What you do is, you have your drawing board and a pencil in hand at the telescope. You look in and you make some markings on the paper and you look in again.” -Clyde Tombaugh, discoverer of Pluto
We often make a big distinction between professional and amateur today, and very rarely expect to find amateurs whose contributions to a major scientific enterprise will change the field forever. Yet back in the 19th Century, even astronomy and physics -- arguably the most developed of the sciences at the time -- had room for pioneers from all walks of life.
Image credit: Copperplate…
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“All things are poison and nothing is without poison; only the dose makes a thing not a poison.” -Theophrastus Phillipus Auroleus Bombastus von Hohenheim
Some scientific topics are so far outside my area of expertise that I need to bring in outside help to do it justice. Today, we're lucky enough to have a guest post from Adrianne Stone, who walks us through the history of mercury and its actual toxicity in various compounds and doses.
Image credit: Associated Press, via http://www.sfgate.com/health/article/Mercury-pollution-a-step-closer-to….
If you've ever simply heard the word mercury…
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“Fantasy is a necessary ingredient in living, it’s a way of looking at life through the wrong end of a telescope. Which is what I do, and that enables you to laugh at life’s realities.” -Dr. Seuss
With 110 objects in the Messier catalogue, and 40 galaxies (more than any other class of object), you might take a "if you've seen one, you've seen them all" attitude. But if you did, you'd be missing out on some truly amazing facts and phenomena happening right here in our own backyard!
Image credit: courtesy of Sloan Digital Sky Survey/WIKISKY, via http://www2011.mpe.mpg.de/highlights.html…
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“Earth as an ecosystem stands out in the all of the universe. There’s no place that we know about that can support life as we know it, not even our sister planet, Mars, where we might set up housekeeping someday, but at great effort and trouble we have to recreate the things we take for granted here.” -Sylvia Earle
When you think of our Solar System, where does your mind go first? If it's like most people, once your thoughts venture away from the Earth, it's very likely that they'll turn to Mars. And if you start thinking about the red planet for very long, you might start thinking about the…
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"I'm a dreamer. I have to dream and reach for the stars, and if I miss a star then I grab a handful of clouds." -Mike Tyson
It's been another busy but fun week over at the main Starts With A Bang blog, where we've gone and looked at:
A Flight Without Stars (for Ask Ethan),
Building your own iron-rich star (for our Weekend Diversion),
A Most Unusual Elliptical, M105 (for Messier Monday),
Happy Earth Day from the Universe,
Striking Cosmic Gold, and
the need for science to inform your politics (for Throwback Thursday).
And, as always, you've come through here on our forum with some outstanding…
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“If the human condition were the periodic table, maybe love would be hydrogen at No. 1.” -David Mitchell
It's the end of the week, so once again it's time for Ask Ethan. You've sent in your questions and suggestions, and have I got a doozy of a question for this week about the simplest element in the Universe: hydrogen.
Image credit: WISE mission, NASA / JPL-Caltech / UCLA, via http://www.nasa.gov/mission_pages/WISE/multimedia/gallery/pia13443.html.
From the Big Bang to the present day, and far into the future, just how much of the Universe's hydrogen has been (or will be) turned…
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“One of my favorite philosophical tenets is that people will agree with you only if they already agree with you. You do not change people’s minds.” -Frank Zappa
I want you to think about your deep, personal convictions. Think about your values, the issues that you feel define you at your core, and your most strongly held beliefs. What, if anything, would compel you to change them?
Image credit: Boise Weekly, via http://www.boiseweekly.com/boise/idahos-epidemic-of-fear-vaccination-li….
Is there any evidence that you could be presented with that would sway you?
Honestly, I sure…
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“Don’t gain the world and lose your soul;
wisdom is better than silver or gold.” -Bob Marley
Going back to ancient times, it's hard to think of a more commonly coveted element than gold. In fact, trying to transmute other elements into it was perhaps the holy grail of the pseudoscience of alchemy, the forerunner of modern chemistry.
Image credit: National Etruscan Museum at Villa Giulia, of Etruscan Gold, via flickr user HEN-Magonza, at http://www.flickr.com/photos/hen-magonza/4256649637/.
Yet, when was the last time you thought about where elements like gold actually came from? It's true…
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“It took less than an hour to make the atoms, a few hundred million years to make the stars and planets, but five billion years to make man!” -George Gamow
Whenever Earth Day comes around, I see a lot of different reactions from people. Some express their passion for the environment, others express disdain for the whole concept as a distraction. Some step up to act as responsible stewards of the world, while others fear nuclear accidents, asteroid strikes or climate change.
Image credit: NASA / Voyager 1. This (cropped) 1977 image is the first photo of the complete Earth and Moon in a single…
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“The line that describes the beautiful is elliptical. It has simplicity and constant change. It cannot be described by a compass, and it changes direction at every one of its points.” -Rudolf Arnheim
It's not every day that a nearby, well-studied galaxy turns your understanding of an entire class of common objects -- in this case, elliptical galaxies -- on its head. But Messier 105 is not your typical elliptical galaxy!
Image credit: Rick Beno of Conferring With The Sky Observatory, via http://www.conferringwiththesky.org/displayimage.php?pid=500.
At 32 million light-years distant, it…
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“Iron helps us play!” -The Simpsons
If you were to peel back the layers of a supermassive star, before it went supernova, what you'd find were a slew of layers abundant in the even-numbers elements up to iron, but little else. Well, this weekend, have I got a fun little find for you! First off, enjoy the sounds of Jeff Austin (and Chris Castino) as they perform the best rendition of
Flatiron Suite
I've ever heard. And then, when you're ready, prepare for a fun and addicting stellar-nucleosynthesis based game: Fe[26].
Image credit: screenshot from http://newbrict.github.io/Fe26…
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"All speech, written or spoken, is a dead language, until it finds a willing and prepared hearer." -Robert Louis Stevenson
It's been another wonderful week in the Universe, and there's been so much to share together. New this week on the main Starts With A Bang blog over at Medium, we've talked about:
Are our students doomed to an inferior education? (For Ask Ethan),
The greatest album covers as seen from behind (For our Weekend Diversion),
A Star-Forming Spiral, M61 (For Messier Monday),
The Astro Alphabet,
How the Sun *really* shines, and
Top 5 Signs of New Physics (For Throwback…