Skip to comments.Life's Building Blocks from Interstellar Space
Posted on 03/28/2002 12:35:53 PM PST by Texaggie79
Life's Building Blocks from Interstellar Space
All living things contain amino acids, and they do all the work of running reactions in the body. They make up all proteins, all enzymes, and form the basis for many other compounds found in living entities.
Historically scientists proposed that to form life on Earth the aminos developed in surface water. However, that did not explain the amino acids found in meteorites or what effect they may have had on developing life.
Now, two groups of scientists have discovered amino acids in laboratory experiments that simulate conditions common in interstellar space. The discovery could solve the mystery of how life developed on Earth and also enhance the possibility that amino acids are common throughout the universe and could be seeding life elsewhere.
"This means they aren't just in our Solar System," said Max Bernstein of the SETI Institute and the NASA-Ames Research Center, both in California. "I'm confident they are in planetary systems throughout the Universe."
Right image: Above is a picture of the vacuum system and cryostat in the astrochemistry lab that is fit with the manual liquid Helium transfer line. With this set-up it is possible to go as cold as 4 K, just four degrees above absolute zero! (that is almost - 270 C or -450 F). Click image to enlarge.
In a laboratory at NASA Ames, the team of astrobiologists led by Bernstein shined ultraviolet light on deep-space-like ices. Deep-space ice is common water ice laced with simple molecules. The team subsequently discovered amino acids, molecules present in, and essential for, life on Earth.
Working independently, Uwe Meierhenrich of Bremen University, Germany, and his colleagues duplicated the experiments, both of which simulated the conditions of deep space using vacuum chambers containing a metal surface chilled to within about a dozen degrees of absolute zero.
They then pumped in a mixture of simple mixtures of molecules (such as wood alcohol and ammonia) found in dense interstellar molecular clouds, in which solar systems are created. Then the teams exposed the resulting ice clouds to UV light. Bernstein's team created three amino acids -- Meierhenrich's found 16.
The amino acids the NASA team detected (glycine, alanine and serine) are the basic parts of proteins from which all life is made. Proteins provide the structure for, and do all the work in, living things.
The amino acids produced in the Ames lab are similar to those found previously in carbon-rich meteorites. The chemical similarities may indicate that amino acids in meteorites were made in deep space, before the solar system formed, the scientists wrote.
"This finding suggests that Earth may have been seeded with amino acids from space in its earliest days," said Jason Dworkin of Ames and the SETI Institute. "And, since new stars and planets are formed within the same clouds in which new amino acids are being created, this increases the odds that life also evolved in places other than Earth."
Previously, members of this team had demonstrated that irradiation of interstellar ice analogs results in the production of other compounds that are also of potential biological interest. These include a class of compounds called amphiphiles that can self-organize to form membranes and a class of compounds called quinones, aromatic ketones that play important roles in the metabolisms of living organisms on the modern Earth.
"Taken in combination, these results suggest that interstellar chemistry may have played a significant part in supplying the Earth with some of the organic materials needed to get life started," said Scott Sandford of the NASA team.
"Taken in combination, these results suggest that interstellar chemistry may have played a significant part in supplying the Earth with some of the organic materials needed to jump-start life," Dworkin concluded.
"This finding may shed light on the origin of life itself," said Bernstein, the first author and chemist at NASA Ames and the SETI Institute. "We found that amino acids can be made in the dense interstellar clouds where planetary systems and stars are made. Our experiments suggest that amino acids should be everywhere, wherever there are stars and planets."
The research will be published in today's issue of Nature magazine. In addition to the principals, other scientists on the Ames team included Doctors Louis Allamandola, George Cooper and Scott Sandford. Astrobiology is the multidisciplinary study of the origin, evolution, distribution and future of life in the universe.
Source: NASA; SETI Institute
Or his novel, "The Black Cloud."
Using cosmic-ray data and stellar spectra gathered by seven satellites, P.C. Frisch, at the University of Chicago, has constructed a cosmic scenario that reminds us of F. Hoyle's science fiction tale, The Black Cloud. According to Frisch, until just a few thousand years ago, the solar system was cruising through interstellar space that was almost devoid of matter. Then, perhaps within historical times, 2,000-8,000 years ago, the solar system plunged into an interstellar gas cloud. This cloud is believed to be the remnant of the bubble of matter shot into space perhaps 250,000 years ago by a supernova in the Scorpius-Centaurus region.
This tenuous cloud of gas feeds matter into the solar system, some of which interacts with the solar wind and, therefore, affects the geomagnetic field, too. Climate changes may have been caused by entry into this cloud, and very likely the flux of cosmic rays impinging on the earth would have been modulated.
(Frisch, Priscella C.; "Morphology and Ionization of the Interstellar Cloud Surrounding the Solar System," Science, 265:1423, 1994. Also: Peterson, I.; "Finding a Place for the Sun in a Cloud," Science News, 146:148, 1994.)
I would also liked to be pinged to threads such as this. I usually don't comment.....but enjoy the read. Is there a ping list for this stuff?
BTW...blam I appreciate you're remembering our e mail conversation on this subject.
You're now on my personal ping list. It's a long way from being official, but it's all I've got.
all the more chances of "some life"..somewhere.
but then it was 3.5 billion years before our consciousness.
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