[meteorite-list] Spitzer Searches for the Origins of Life

From: Ron Baalke <baalke_at_meteoritecentral.com>
Date: Wed, 13 Jun 2007 14:29:31 -0700 (PDT)
Message-ID: <200706132129.OAA24996_at_zagami.jpl.nasa.gov>

http://www.jpl.nasa.gov/news/features.cfm?feature=1396

Spitzer Searches for the Origins of Life
Jet Propulsion Laboratory
June 13, 2007

Astronomers suspect the early Earth was a very harsh place. Temperatures
were extreme, and the planet was constantly bombarded by cosmic debris.
Many scientists believe that life's starting materials, or building
blocks, must have been very resilient to have survived this tumultuous
environment.

Now, NASA's Spitzer Space Telescope has learned, for the first time,
that organic molecules believed to be among life's building blocks,
called polycyclic aromatic hydrocarbons, can survive another type of
harsh setting, an explosion called a supernova. Supernovae are the
violent deaths of the most massive stars. In death, these volatile
objects blast tons of energetic waves into the cosmos, destroying much
of the dust surrounding them.

The fact that polycyclic aromatic hydrocarbons can survive a supernova
indicates that they are incredibly tough - like cosmic cockroaches
enduring a nuclear blast. Such durability might be further proof that
these molecules are indeed among life's building blocks.

Achim Tappe of the Harvard-Smithsonian Center for Astrophysics,
Cambridge, Mass., used Spitzer's infrared spectrograph instrument to
detect abundant amounts of polycyclic aromatic hydrocarbons along the
ridge of supernova remnant N132D. The remnant is located 163,000
light-years away in a neighboring galaxy called, the Large Magellanic
Cloud.

"The fact that we see polycyclic aromatic hydrocarbons surviving this
explosion illustrates their resilience," says Tappe.

These intriguing molecules are comprised of carbon and hydrogen atoms,
and have been spotted inside comets, around star-forming regions and
planet-forming disks. Since all life on Earth is carbon based,
astronomers suspect that some of Earth's original carbon might have come
from these molecules ? possibly from comets that smacked into the young
planet.

Astronomers say there is some evidence that a massive star exploded near
our solar system as it was just beginning to form almost 5 billion years
ago. If so, the polycyclic aromatic hydrocarbons that survived that
blast might have helped seed life on our planet.

Tappe's paper was published in the December 10, 2006, issue of
Astrophysical Journal.
Received on Wed 13 Jun 2007 05:29:31 PM PDT