Siberia is one of scientist Andy Knoll's favorite places on Earth. Knoll
has traveled the world as a paleontologist hunting fossils that tell us
about ancient life on our planet - Siberia is one prime location for
ancient fossils. For the last 20 years he's searched for evidence of the
Earth's biological past in rocks and soil from Massachusetts to
Manchuria. Now, as an astrobiologist with the Athena Mars Missions, he's
taking that search to Mars.
The science of looking for life beyond our Earth, astrobiology is a
fairly new science born of the space age - but the fundamental methods
of traditional science still apply. Professor Knoll, a Professor of
Biology and Curator of the Paleobotanical Collections at Harvard
University, knows how to find very old fossils by understanding what
kind of geological terrain holds the most promise. Discovering ancient
biological clues requires knowing how and where to look for fossils -
the exact expertise that the Athena teams will need when they are
collecting and choosing martian samples for the long journey back to
Earth.
"The goal is to look for rocks that might have something in them,"
explains Knoll, "but we won't find out if they do until they come back
to Earth. So we're particularly guided by the successful strategies we
use on Earth. We've learned how different types of rocks can help us
answer questions."
On Mars, however, there are very real limits on the search. First of
all, there is a time limit - the Athena rover will only have a few
months to collect samples before the soccer-ball-shaped collection
container is blasted into orbit for pick-up. The next limitation is the
search area. Although the landing site is specifically chosen for the
greatest likelihood of finding fossils, there's a whole planet to search
and only a small region the rover can cover. Lastly, the samples won't
be cracked open and examined until they are brought back to Earth in
2008, which makes determining what to keep and what to throw back a
tough and momentous decision.
As Knoll describes, "Choosing a rock on Mars is an amazing prospect -
each specimen is specifically selected to be examined. When making the
selection on Earth, an experienced paleontologist picks up the rock,
looks at it, holds it, perhaps shakes it - and within 3 minutes it's
usually clear whether the sample is worth further examination. On Mars,
that process can take a whole day."
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Noontime on Mars. This color picture of Mars was taken July 21--the day following Viking I's successful landing on the planet. |
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Keeping the excitement alive throughout the years between launching the
samples into orbit around Mars and landing on Earth three years later
will be a challenge, but the prospect of discovery may be just enough to
keep people like Andy Knoll on the edge of their seats.
"Discovering a new fossil is a thrilling experience every time. It's
the whole experience from going to the rocks, choosing one, breaking it
open, and finding valuable clues and evidence from our history,"
describes Knoll, who discovered a passion for paleontology early in
life.
"I was probably 11 years old, and I was looking in what I now know to be
Devonian rocks, when I broke open a rock to discover a magnificent
Brachiopod," tells Knoll of his first find in the foothills of the
Appalachian Mountains. After that, he was hooked.
There is no guarantee of finding ancient life on Mars - there has been
no definitive proof up to now - but the endeavor to find life and
explore our neighboring planet Mars should prove especially rewarding.
Says Knoll, "If in 2008, when our samples come back we find signs of
life, it will be extraordinary... but no matter what, we'll still learn
a lot about Mars."
