Skip to comments.Amino acid found in deep space
Posted on 07/18/2002 10:17:50 AM PDT by nuda_veritas
|10:57 18 July 02|
|Exclusive from New Scientist Print Edition||
An amino acid, one of the building blocks of life, has been spotted in deep space. 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.
This would add weight to ideas that life exists on other planets, and even that molecules from outer space kick-started life on Earth.
Over 130 molecules have been identified in interstellar space so far, including sugars and ethanol. But amino acids are a particularly important find because they link up to form proteins, the molecules that run, and to a large extent make up our cells.
Back in 1994, a team led by astronomer Lewis Snyder of the University of Illinois at Urbana-Champaign announced preliminary evidence of the simplest type of amino acid, glycine, but the finding did not stand up to closer examination (New Scientist magazine, 11 June 1994, p 4).
Now Snyder and Yi-Jehng Kuan of the National Taiwan Normal University say they really have found glycine. "We're more confident [this time]," says Kuan. "We have strong evidence that glycine exists in interstellar space."
The researchers monitored radio waves for the spectral lines characteristic of glycine. They studied emissions from more locations than before - giant molecular clouds, huge blobs of gas and dust grains. They have also identified 10 spectral lines at each location that correspond to the lines created by glycine in the lab; before they had just two.
The discovery of glycine supports recent lab-based simulations of deep space, which show that ices containing simple organic matter could form. When researchers bathe those ices in ultraviolet light, amino acids are created.
"Glycine is the holy grail," says Jill Tarter, director of the Centre for SETI Research at the SETI Institute in Mountain View. "Let's hope they've got it this time."
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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.
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.
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.
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.
"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.
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."
That makes me suspicious of the source. This link kinda sobered me up to the difficulties in obtaining the necessary reactants.
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).
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.
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 --|
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."
Note: this topic is from 7/18/2002. Thanks nuda_veritas (wherever you are).
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Note: this topic is from 7/18/2002.