Amino acid found in deep space

New Scientist ^ | 10:57 18 July 02 | Rachel Nowak

[rintense]

Amino acid in space? Surely this is Bush's fault.

[gore3000]

Then, lacking evidence, why did you claim that there were no amino acide in the Murchison meteorite?

No, I did not say I lacked evidence, I said I was not going to waste my time finding an article I read a while back. Fact is that they would still be looking for amino acids in space if they had already been found and that is better proof than any article.

[Doctor Stochastic]

Your post shows an abysmal ignorance of scientific endeavor. Just because there are amino acids in a meteorite that doesn't mean it isn't interesting to find amino acids other places. Science is much broader in its inquiry than your posts show.

[PatrickHenry]

Placemarker.

[AndrewC]

Your post shows an abysmal ignorance of scientific endeavor. Just because there are amino acids in a meteorite that doesn't mean it isn't interesting to find amino acids other places. Science is much broader in its inquiry than your posts show.

It is not abysmal ignorance to point out a lack of coherence in the stipulations of "science". I have read evidence of contrary evidence to the assertions made about the Murchison, but I believe it had to do with the "life forms" in the rock. I also seem to remember that contamination could not be ruled out as the source of the amino acids, but I am not sure of that. I, like gore3000, feel that it is a waste of time searching for the sources. It seems sufficient to point out the statement --- . If the find stands up to scrutiny, it means that the sorts of chemistry needed to create life are not unique to Earth verifying one of astrobiology's cherished theories. seems to imply that no other evidence of these compounds (in the environment mentioned) exists.

[Doctor Stochastic]

I, like gore3000, feel that it is a waste of time searching for the sources.

Which is why your posts have little substance. Undocumented claims have no validity. A quick search of current articles on the Murchison metreorite showed no retraction as gore3000 claimed.

[SkyRat]

I wouldnt be suprised if we find multi cellular life on Europa. While this moon of Jupiter lacks an athmosphere, it has liquid water (actually a whole ocean of H2O) and vulcanic activity. Water and heat is enough to support a ecosystem. Look up black smokers

[AndrewC]

Which is why your posts have little substance.

Is that why you are dodging the quote on this thread from the source document? What is your spin on the quotation that on face value practically asserts no other evidence exists? In case you have forgotten, here it is again.

If the find stands up to scrutiny, it means that the sorts of chemistry needed to create life are not unique to Earth verifying one of astrobiology's cherished theories.

If the Murchison was already accepted as having amino acids, how can the preceding statement have any meaning? The "sorts of chemistry needed to crate life are not unique to Earth" would have already verified one of astrobiology's cherished theories.

So much for the substance of your post.

[AndrewC]

I wouldnt be suprised if we find multi cellular life on Europa. While this moon of Jupiter lacks an athmosphere, it has liquid water (actually a whole ocean of H2O) and vulcanic activity.

Carbon source?

[gitmo]

Didn't they find a lot of amino acids in moon dust?

[Doctor Stochastic]

You and gore3000 are the only ones dodging anything here. Gore3000 claimed that the occurence of amino acids in the Murchison meteorite had been retracted; then you claimed that you didn't need to show any references. All I claimed is that a search of journals showed no such retraction for the last two years.

If you have a published retraction in a refereed journal, please post it.

[Nebullis]

The latest count of amino acids found on meteorites that I know of is 70. There's some indication that the precursors were formed from interstellar dust.

[Nebullis]

What's more, there's an excess of L-enantiomers. Cool, no?

[AndrewC]

You and gore3000 are the only ones dodging anything here. Gore3000 claimed that the occurence of amino acids in the Murchison meteorite had been retracted; then you claimed that you didn't need to show any references. All I claimed is that a search of journals showed no such retraction for the last two years.

"All you have done" is justify my original statement on this! It would have been a waste of time to post anything, since you apparently don't read what is posted or do not understand what is posted. First, I stated that the evidence I had seen was in relation to suspected life forms (from Mars) on the Murchison. The only claim I made about posting a reference is that it would have been a waste of time. My real aim in post 105 was to point out that this thread, you know the one we should be discussing, makes a claim which implies a lack of evidence for the extraterrestrial amino acids elsewhere. You have continually failed to answer that.

To ease your palpitating little heart, I will post a link in support of my claim. I expect others will gain from it contrary to your apparent lack of gumption.

Questions over fossilized bacteria in old meteorite

Dr Andrew Steele from the University of Portsmouth told SPACE.com "meteorites become contaminated with Earth life within days of landing, yet some of the Murchison meteorites were in the open for four to five months before being collected."

[AndrewC]

What's more, there's an excess of L-enantiomers. Cool, no?

That makes me suspicious of the source. This link kinda sobered me up to the difficulties in obtaining the necessary reactants.

The photostability of amino acids in space

The experimental results indicate that amino acids in the gas phase will likely be destroyed during the lifetime of a typical interstellar cloud. In regions with relatively low UV radiation, amino acids may be present as transient gas-phase species. Their survival in interstellar icy grain mantles and on the surface of comets and planets is also strongly limited. These results provide important constraints for the survival and transfer of amino acids in space environments, and thus their possible availability for prebiotic chemistry.

The actual paper is here, and is recent(March 2001).

5. CONCLUSION

Amino acids are highly susceptible to UV photodestruction, even under exposure to UV photons of relatively low energy. Their limited photostability suggests that amino acids have not been detected because they are destroyed before they can accumulate in the gas phase. Although amino acids may be detected by radio observations in UV-shielded environments (such as hot cores), merely traces will survive in any environment with an elevated UV flux. This applies to both interstellar and solar system environments, at least out to distances of 5 AU, and would appear to be inconsistent with recent studies of the survival of amino acids in Earth orbit (Barbier et al. 1998).

Our results place constraints on the inventory of amino acids for exogenous delivery to the early Earth and thus on prebiotic evolution. However, this does not preclude the amino acids in meteorites having formed in the ISM. It simply requires that amino acids be shielded from UV in protected environments, such as in dust grains and meteorites and in the interiors of small bodies, i.e., comets and asteroids prior to delivery to early planets.

Here is a link giving somewhat of a blow by blow on amino acids and extraterrestrial origin.

The Net Advance of Physics: ANNOTATED BIBLIOGRAPHIES, No. 1

[Doctor Stochastic]

Not exactly a refereed journal, but anything is useful.

Where did you get the idea that Mars had anything to do with the Murchison Meteorite? It's always been known that this meteorited didn't come from Mars. There was a Martian meteorite for whick some controversial claims of bacteria-like organisms was made. That claim was retracted. So far no claim of bacteria-like organisms on meteorites has stood up whereas the amino acid claims have.

Still no retraction in refereed journals that extra-terrestial amino acids were found on the Murchison.

One of Gore3000's claim was that one would quit looking in space for amino acids if such acids were found in a meteorite. You seemed to support that claim.

[AndrewC]

Where did you get the idea that Mars had anything to do with the Murchison Meteorite?

Sorry, you are correct in pointing out my error. It did have purported life-forms and was discussed along with ALH84001, the martian meteorite, in the article I recalled. I mixed the two. The evidence of life forms has been in dispute and that was the reference of my post.

Here is a different article with an image of the "life forms". 27 January 2000: FOSSILIZED BACTERIA IN MURCHISON AND EFREMOVKA

Murchison meteorite: bacteriomorphic structure similar to filamentous microorganisms with preserved cell fragmentation, like cyanobacteria of Lyngbya or Oscillatoria genera --

[Nebullis]

That makes me suspicious of the source.

Enantiomeric Excesses in Meteoritic Amino Acids J. Cronin and S. Pizzarello Science (1997)275:942.

Racemic amino acids from the ultraviolet photolysis of interstellar ice analogues M. Bernstein et al. Nature (2002)416:401.

From the abstract: "Here we report a laboratory demonstration that glycine, alanine and serine naturally form from ultraviolet photolysis of the analogues of icy interstellar grains. Such amino acids would naturally have a deuterium excess similar to that seen in interstellar molecular clouds, and the formation process could also result in enantiomeric excesses if the incident radiation is circularly polarized. These results suggest that at least some meteoritic amino acids are the result of interstellar photochemistry, rather than formation in liquid water on an early Solar System body."

[Doctor Stochastic]

The people I talked to about the purported bacteria in the Martian meteorite didn't think much of the possibility. The microscopic tubes looked like crystalization rather than organic. They were very small for bacteria. The amino acids are thought to be extra-terrestrial because they are racemic and those occuring on Earth are generally optically active.

[SunkenCiv]

Note: this topic is from 7/18/2002. Thanks nuda_veritas (wherever you are).

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