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NASA Discovers Life's Building Block In Comet
xp65 writes "NASA scientists have discovered glycine, a fundamental building block of life, in samples of comet Wild 2 returned by NASA's Stardust spacecraft. 'Glycine is an amino acid used by living organisms to make proteins, and this is the first time an amino acid has been found in a comet,' said Jamie Elsila of NASA's Goddard Space Flight Center in Greenbelt, Md. 'Our discovery supports the theory that some of life's ingredients formed in space and were delivered to Earth long ago by meteorite and comet impacts.'"
No, all it means is that some of the chemicals needed for Earthly life are also found in elsewhere in the Solar System. Given that the entire Solar System formed out of the same molecular cloud that is not very surprising.
Just because you are paranoid does not mean that no-one is out to get you.
Ha!
q: Whats the difference between average slashdotter and average comet?
a: one gets to spread its "life's building blocks" around
Um... it didn't. "Building blocks for life" does not equal "life". But once the 'building blocks' formed, life could get started... almost certainly on Earth. See, e.g., here.
PHEM - party like it's 1997-2003!
"What caused the life to form way out there?"
As far as we can tell life didn't form way out there. Just an amino acid fundamental to life. Life as we know it requires liquid water, a certain atmosphere, gravity, and a bunch of other requirements.
"It's fine and dandy to push the building blocks of life off-planet, but how can those blocks then be explained?"
The building blocks for life have to come from somewhere, they don't just appear out of nowhere (or do they?). After all, isn't life really just the combination of left over heavier elements created through exploded stars and other space junk that just happened to end up on earth through meteorites, comets, and the accretion process...
Glycine is the only thing they are willing to admit. NASA believes the world is not in a position to digest, (ha, ha) the more significant finding in the comet: High Fructose Corn Syrup.
sed -e 's/Chuck Norris/Rajnikant/g' joke > fact
Glycine is the simplest amino acid, and it the only one that lacks a chiral center on the alpha carbon. Of the four groups attached in a tetrahedral arrangement to the alpha carbon, two are hydrogen atoms. In all other amino acids, one of the two hydrogens of glycines is replaced by a distinct functional group. The really interesting thing about biologically used amino acids is that it is always the same hydrogen of the two that is replaced -- all the 19 non-glycine amino acids are so-called "L-stereoisomers." Discovery of any one of the 19 amino acids other than glycine in a comet would be quite a story, and it would be even more surprising if there were a mixture of "L" and "D" stereoisomers other than 50/50. My bet is that if another amino acid is found in cometary debris, it is asparagine, since it can form by the reaction 2*glycine - water.
We spread "life's building blocks" around too. It's just that there's no fertile "tracts of land" to receive them.
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"Our discovery supports the theory that some of life's ingredients formed in space and were delivered to Earth long ago by meteorite and comet impacts."
Instead it only supports what Dr. Pilcher says in the article:
"The discovery of glycine in a comet supports the idea that the fundamental building blocks of life are prevalent in space, and strengthens the argument that life in the universe may be common rather than rare."
In other words, it's just saying that amino acids are not that rare. If they're not that rare, why can't Earth have made them on it's own?
After all the Miller/Urey experiment in 1953 showed that amino acids can be produced fairly easily if a few simple conditions are met.
Miller took molecules which were believed to represent the major components of the early Earth's atmosphere and put them into a closed system
The gases they used were methane (CH4), ammonia (NH3), hydrogen (H2), and water (H2O). Next, he ran a continuous electric current through the system, to simulate lightning storms believed to be common on the early earth. Analysis of the experiment was done by chromotography. At the end of one week, Miller observed that as much as 10-15% of the carbon was now in the form of organic compounds. Two percent of the carbon had formed some of the amino acids which are used to make proteins.
Maybe comets and meteors with amino acids were hitting earth as well. But finding them all over space also strengthens the idea that they're not uncommon to produce, and therefore also strengthens the theory that Earth could have produced them by itself. Either way seems like a guess to me.
Fun fact for the day: The Murchison meteorite which fell in Australia in 1969 also contained common amino acids such as glycine, alanine and glutamic acid as well as unusual ones like isovaline and pseudoleucine.
1) it was scooped from earth or another planet with life by the comet: dubious
2) a planet with life somewhere got crushed and the ejected material that formed the comet got some amino acids in it. weakly possible.
3) Given it's been shown that freezing primordial materials found in space actually promotes the formation of nucleic acids, it might not be much of a reach to suppose that there are natural processes in cold space that will form amino acids.
4) there are life forms that live on comets. presumably then panspermia is ubiquitous.
5) the gel got contaminated on earth. or the mass spec is not definitive about the molecule in question.
I lean towards 5, and then 3 as a close second. Of course 4 would be interesting, as it's direct panspermia. But if indeed the building blocks of life as we know it pervade the universe and occur naturally it also suggests there probably are a lot of similar nucloetide/peptide base life forms out there.
Some drink at the fountain of knowledge. Others just gargle.
Actually, you're wrong there. As one example, life on earth is composed of right-handed sugars and and left-handed amino acids, but as far as we can tell there's no particular reason why that configuration had to happen - it was a random configuration which manifested early in the development of terrestrial life and spread to all existing species. This means we can only process food with that particular molecular makeup. Early artificial sweeteners took advantage of this fact - their manufacturers figured out how to make left-handed sugars which we could taste, but couldn't digest. In other words you can eat it and it won't cause you any harm, but you won't get any energy from it. What this means is that there would be, at best, only a 25% chance of us being able to use your hypothetical life-forms as a food source, and that's without having to worry about whether they provide us with the right vitamins/nutrients, what sorts of hormones and toxins might be in them, etc.