Scientists have found the beginnings of life-bearing
chemistry at the center of the galaxy.
Iso-propyl cyanide has been detected in a
star-forming cloud 27,000 light-years from Earth.
Its branched carbon structure is closer to the
complex organic molecules of life than any previous finding from interstellar
space.
The discovery suggests the building blocks of life
may be widespread throughout our galaxy.
Various organic molecules have previously been
discovered in interstellar space, but i-propyl cyanide is the first with a
branched carbon backbone.
The branched structure is important as it shows that
interstellar space could be the origin of more complex branched molecules, such
as amino acids, that are necessary for life on Earth.
Dr
Arnaud Belloche from the Max Planck Institute for Radio Astronomy is
lead author of the research, which appears in
the journal Science.
"Amino acids on Earth are the building blocks
of proteins, and proteins are very important for life as we know it. The
question in the background is: is there life somewhere else in the
galaxy?"
The molecule was detected in a giant gas cloud
called Sagittarius B2, an active region of ongoing star formation in the centre
of the Milky Way.
As stars are born in the cloud they heat up
microscopic dust grains. Chemical reactions on the surface of the dust allow
complex molecules like i-propyl cyanide to form.
The molecules emit radiation that was detected as
radio waves by twenty 12m telescopes at the Atacama Large Millimeter Array (Alma) in
Chile.
Each molecule produces a different "spectral
fingerprint" of frequencies. "The game consists in matching these
frequencies… to molecules that have been characterized in the laboratory,"
explained Dr Belloche.
"Our goal is to search for new complex organic
molecules in the interstellar medium."
Previously discovered molecules in the Sagittarius
B2 cloud include vinyl alcohol and ethyl formate, the chemical that gives
raspberries their flavor and rum its smell.
But i-propyl cyanide is the largest and most complex
organic molecule found to date - and the only one to share the branched atomic
backbone of amino acids.
"The idea is to know whether the elements that
are necessary for life to occur… can be found in other places in our
galaxy."
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