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Life's Building Blocks Found On Asteroid 24 Themis
Hugh Pickens writes "The LA Times reports that scientists analyzing infrared light reflected by 24 Themis, one of the largest asteroids in the solar system, have discovered evidence of water ice as well as organic compounds — findings that bolster a leading theory for the origins of life on Earth that the essential building blocks of life came from asteroids. 'Up until now there was no sign that asteroids had any abundant organics or ice on them,' says Joshua P. Emery, a planetary astronomer at the University of Tennessee. Typically, ice on the surface of an object such as 24 Themis would quickly vaporize and vanish, says planetary scientist Richard Binzel. 'Seeing freshly exposed ice on the surface, now that's a surprise. It has to be replenished from below, somehow.' The possibility that water could have come from asteroids adds weight to the theory that water and organic molecules may not have originated on Earth because the Earth did not become conducive to water or organic molecules until relatively recently."
If their argument is that early Earth wasn't conducive to water, it's not clear how bringing in organics and water would help. If you bring in organics to a hot planet, they'll break apart just as surely as if they had formed there, after all.
It's never been clear to me why this mechanism is any better than just forming the danged organics on Earth surface. The Urey-Miller experiments demonstrated nicely that you can form organics under a wide range of conditions. (Which ones correspond to early Earth is an outstanding question, but it doesn't appear to much matter, oddly.)
Come to all that, we don't know that these asteroids (assuming they are asteroids and not dead comets, which it kind of sounds like they may be...) had much in the way of organics 4 billion years ago or if the organics formed due to reactions since then.
Basically, I'm uncomfortable with how excited people seem to get about the idea that this might have delivered the "building blocks of life" to Earth. Possible, sure, but it's far from a strong case.
"findings that bolster a leading theory for the origins of life on Earth that the essential building blocks of life came from asteroids."
No it doesn't, that "leading theory"(*) is untestable and completely ignores contra evidence. Hydrogen, Oxygen and Carbon are respectively the 1st, 3rd and 4th most abundant elements in the universe. Hydrogen and oxygen combust to create water. Modern day volcanos spew all three elements out in large quantities, mainly as water vapour and carbon based molecules. If a rock 100 odd km across has organics and water what in the world make anyone think that a rock over 6000 km in diameter formed from the same primordial material would have have none?
While it's certainly very likely that some water and organics arived via asteroids, frankly the ridiculous improbability that ALL of it arrived via asteroids is too fucking stupid for words. Such psuedo-scientific claptrap only detracts from what is an otherwise fascinating discovery.
(*) = Here is what a real leading theory for abiogenisis looks like; "no ridiculous improbability, no supernatural forces, no lightning striking a puddle, just chemistry", and with a great soundtrack to boot!
And did you exchange a walk on part in the war for a lead role in a cage? - Pink Floyd.
The water on the surface of 24 Themis does not have to come from within the asteroid, it can be created through surface chemistry between the solar wind and the surface of the asteroid. The process is similar what has been proposed to explain some of the water layer found on the surface of the Moon. In essence, the water on the asteroid is being continually created. Water that is lost is replaced through chemical reactions over time.
Just because you are paranoid does not mean that no-one is out to get you.
"findings that bolster a leading theory for the origins of life on Earth that the essential building blocks of life came from asteroids"
bullshit, this is not a leading theory, rather calling it a "wacky theory" could be a better description...
metageek
Life, Shmife! We are not focusing on the most important aspect of this report. The key is that there is sizable amounts water available in (relatively) nearby orbits outside of any significant gravity well. If the water can be used to refuel ships on their way to outer orbits, this could be incredibly useful for deep space exploration. I would personally prefer to see a space station on 24 Themis than on the moon, and it is less work to get there. Ok, more time but less work.
"I love his boyish charm, but I hate his childishness" - Leela
Great, now I'm gonna spend all day doing the dimensional analysis to get from X asteriods of water to Y Libraries of Congress. I'll let someone else dig up the relevant xkcd link.
The theory goes that a mars sized planetoid, named Theia, had formed at earths L4 or L5 Lagrangian points. As it's mass grew due to impacts, it was no longer stable at that point, and slammed into earth. The resulting debris cloud came together to form the moon.
See http://en.wikipedia.org/wiki/Giant_impact_hypothesis
"I'm glad that two teams independently verified it but I'm a little concerned that there may be a flaw in the methodology of the reflection of the light. I'm sure they've accounted for everything but I'm just concerned because the only logical explanation is either our fundamental understandings of asteroids is largely incomplete (the first one they picked was laden with organic molecules where normally there are but a few traces) or the methodology of determining their composition falls prey to some unforeseen phenomenon/distortion in this case."
Yes but note that they didn't pick this asteroid at random, they picked it because it was the brightest one known and thus easier to perform the spectral analysis. Ice is highly reflective and probably explains the unusual brightness, it doesn't automatically imply that all asteroids have a similar makeup.
And did you exchange a walk on part in the war for a lead role in a cage? - Pink Floyd.
how many asteriods must have crashed into the earth to get all the oceans???
Minimum seven, if each one falls into a different ocean.
It is dangerous to be right when the government is wrong.
this picture provides a very good idea of the total volume of water on earth.
But ... there' only one ocean.
Lost at C:>. Found at C.
It would be interesting if life in the Universe was similar enough because planets that bear life are "seeded" in such a way. Frightening, too. That means it's possible that humans might be susceptible to microbes found on other planets.
That statement belies an amazing ignorance about how tightly adapted diseases are to their hosts. You do realize that we're immune to all but the tiny fraction of microbes on Earth which are adapted to live in the ecosystem that is our bodies, right? Why would random space microbes be capable of surviving inside of us?
We can't even get most of the same diseases dogs get, much less germs that survive on frozen, irradiated asteroids.
If it's for-profit but free, you're not the customer -- you're the product (e.g., the Slashdot Beta's "audience").
I'm not a panspermian, but consider what will happen if humanity is currently the only intelligent life in this galaxy or even small area of the galaxy. In a thousand years (if the computers don't exterminate the meatbags and/or have an interest in planets), most planets (in this area) will have received (organic) life from outer space. Personally, I have no desire to colonize other (uninhabited) planets, and would be perfectly happy just to live in solar space (around our sun or another, if it were possible), but I think it will be unlikely that all of humanity will agree with me on that. Even if they agree, they'll at least take a look, and it is notoriously difficult to eradicate bacterial (or archaean) spores in sterilization procedures (our hypothetical non-organic successors may have an easier time, though)...
Consider what would happen if someone seeds moderately Earthlike planets with primitive Earth lifeforms and then leaves it to mature for a billion years. The intelligent life that might evolve could turn into a bunch of unimaginative panspermians, or it could figure out how life could have arisen on its own planets (and did...probably...on Earth).
The TFS implication that (many) people are excited about this from a panspermia perspective is misleading. The thrust of TFA #1 is that it is more difficult for organic compounds to form on an asteroid. The thrust of TFA #2 is that scientists apparently wonder how the Earth came to be covered with water after a catastrophic collision formed the Moon and the surface was superheated. Apparently the water on this asteroid is more similar (in deuterium concentration? TFA is horribly misleading and vague) to the oceans than the water generally found in comets.
I leave you with Christian Science Monitor "science" reporting (not that it's worse than CNN, NYT, PhysOrg, etc.).
But the forms of hydrogen in water molecules bound in asteroids are a closer match to those found in seawater than are those found in water comets carry.