Fundamental Ingredient for Life Discovered in Comet

A fundamental ingredient for life has been discovered in a comet sample, supporting the idea that such icy objects seeded early Earth with the stuff needed to whip up living organisms.

New research firms up past suggestions of glycine, the simplest amino acid used to make proteins, inside samples from the comet Wild 2 (pronounced "Vilt 2").

"This is the first time an amino acid has been found in a comet," said lead researcher 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."

How life arose on Earth has long puzzled scientists and philosophers alike, with possible evidence for such building blocks showing up floating about in the cosmos and even inside the mouths of volcanoes.

The new finding, which has been accepted for publication in the journal Meteoritics and Planetary Science, also has implications for finding alien life.

"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," said Carl Pilcher, director of the NASA Astrobiology Institute, which co-funded the research.

NASA's Stardust spacecraft captured samples of gas and dust from Wild 2 in 2004. The material parachuted to Earth in 2006. Since then, scientists around the world have been analyzing the samples to learn the secrets of comet formation and our solar system's history.

Preliminary testing had suggested glycine was present in the samples. But since glycine is used by terrestrial life, the team couldn't rule out contamination from Earthly sources, according to a NASA statement released today.

"It was possible that the glycine we found originated from handling or manufacture of the Stardust spacecraft itself," Elsila said.

To tease apart contamination from the real McCoy, the researchers recently analyzed the samples for different carbon isotopes, which are versions of the same element with different masses.

Glycine molecules from space tend to have more of the heavier Carbon 13 atoms than glycine from Earth. That's exactly what the team found.

"We discovered that the Stardust-returned glycine has an extraterrestrial carbon isotope signature, indicating that it originated on the comet," Elsila said.

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Devill said:

Wonder when they are going to create life from non-living matter.

I mean a lot of scientists say that they know how and under which conditions it happened so I'm just wondering why we have not done it yet.

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Where and how did the complex genetic instruction set programmed into DNA come into existence? The genetic set may have arisen elsewhere and was transported to the Earth. If not, it arose on the Earth, and became the genetic code in a previous lifeless, physical–chemical world. Even if RNA or DNA were inserted into a lifeless world, they would not contain any genetic instructions unless each nucleotide selection in the sequence was programmed for function. Even then, a predetermined communication system would have had to be in place for any message to be understood at the destination. Transcription and translation would not necessarily have been needed in an RNA world. Ribozymes could have accomplished some of the simpler functions of current protein enzymes. Templating of single RNA strands followed by retemplating back to a sense strand could have occurred. But this process does not explain the derivation of “sense” in any strand. “Sense” means algorithmic function achieved through sequences of certain decision-node switch-settings. These particular primary structures determine secondary and tertiary structures. Each sequence determines minimum-free-energy folding propensities, binding site specificity, and function. Minimal metabolism would be needed for cells to be capable of growth and division. All known metabolism is cybernetic – that is, it is programmatically and algorithmically organized and controlled.

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Devill said:

Wonder when they are going to create life from non-living matter.

I mean a lot of scientists say that they know how and under which conditions it happened so I'm just wondering why we have not done it yet.

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mercurial said:

My guess is that some of them already have, but we both know what outcry there will be if that knowledge were made public...

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Geriatrix said:

They don't know how, at least not yet. They can take educated guesses but I think they're still working on the exactly how. I'm sure it will be headline news when some one cracks it.

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Devill said:

Mmm then they should stop saying they know how it happened and that they understand the process... I hate it even more when scientists lie then when religious people lie.....

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Geriatrix said:

I don't think they say that they do(maybe some do), its the media misrepresenting what they say. I posted a cartoon in the science joke thread a while back illustrating this.

Its like this; scientist reports that they figured out how to mix two chemicals vaguely related to milk digestion, media reports that scientists cured lactose intolerance.

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Devill said:

Lol. Yes sometimes buuuuuut the media can not be blamed for everything everytime

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Geriatrix said:

Yes sometimes its Apartheids fault...

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