[meteorite-list] Life's Origins Among The Stars

From: Ron Baalke <baalke_at_meteoritecentral.com>
Date: Thu Apr 22 10:02:34 2004
Message-ID: <200203312321.PAA18041_at_zagami.jpl.nasa.gov>

http://news.bbc.co.uk/hi/english/sci/tech/newsid_1897000/1897186.stm

Life's origins among the stars

A salt inclusion in a meteorite is evidence of water

By Dr David Whitehouse
BBC News
March 27, 2002

New evidence that the building blocks of life are scattered in clouds
between the stars is reported in two research papers in the journal
Nature.

By simulating the supercold conditions found in space, researchers
have shown that tiny ice grains can play host to important reactions
when irradiated by ultraviolet light.

In the experiments, atoms were assembled into amino acids, the
basic components of proteins, the sophisticated molecules that build
and maintain living organisms.

The researchers say it is possible that such ice grains could have
become incorporated into the cloud that formed our Solar System
and ended up on Earth, helping life to start.

In between the stars

Several lines of evidence suggest that some of the building blocks of
life were delivered to the primitive Earth via meteoroids.

But scientists would still like to know how they got into the
meteoroids in the first place.

There appear to be two ways. One suggestion is that complex
chemical reactions involving water took place on, or in, the rocky
bodies that formed when the Solar System was young.

These reactions produced a variety of amino acids. For example,
analysis of the famous Murchison meteorite shows that it contains
70 kinds of amino acids.

But writing in the journal Nature, two independent groups, one led
by Max Bernstein of the Seti Institute in the US and the other by
Uwe Meierhenrich of Bremen University, Germany, put forward
another scenario.

Life out there

This involves chemical reactions on the ice grains that inhabit
interstellar space.

The researchers carried out experiments that simulated the
conditions found between the stars, using ultraviolet radiation and
temperatures around minus 258 degrees Celsius (that is 15 degrees
above absolute zero).

Into these conditions they introduced some of the molecules that
are known to be drifting in space, such as carbon monoxide and
ammonia.

Both teams reported the formation of amino acids, such as glycine,
alanine, serine and proline.

The experiments were not identical, however. One team used an
initial mixture that was rich in water; the other team used a
water-deficient compound that produced far more amino acids.

This research adds to the growing body of evidence that the
formation of complex molecules occurs in many different
environments in the cosmos, and will it will encourage those who
believe that life is widespread in the Universe.
Received on Sun 31 Mar 2002 06:21:27 PM PST