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Earth's attic
Astronomy's Guillermo Gonzalez thinks there's a good possibility
that clues to the origin of life could exist on the Moon.
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Could some of life's greatest mysteries not even be on this planet?
That's the thinking of Guillermo Gonzalez, assistant professor of physics
and astronomy. Gonzalez and a team of researchers from the University
of Washington have put forth an hypothesis that could lead to testing
origin of life theories.
"There are very few places you can go on this planet that preserves
the clues to the origin of life because of the Earth's activity geology,"
Gonzalez said.
Rain, wind, tides, plate tectonics and other natural forces have largely
eroded any clues the Earth may have held.
That got Gonzalez to thinking that maybe some clues may exist elsewhere.
"I thought since we're having a hard time studying the origin of
life on Earth there must be some other way to look at this problem,"
he said. "And it just occurred to me that the Moon is the perfect
place to preserve any clues."
Gonzalez and his research team have produced calculations that suggest
that there is a strong chance that asteroid impacts on the Earth around
3.8 billion years ago produced enough debris from the Earth to make its
way to the Moon. Some of the terrestrial rock may have been vaporized
when it hit the Moon, other debris may have gone on past the Moon and
evidentially landed on Mars and other planets.
But Gonzalez feels that the Moon may have been the final resting place
for numerous samples of the Earth. Since there is much less erosive environment
on the Moon than exists on the Earth (no wind or water exists on the Moon),
those samples are still residing on the lunar surface. Micrometeorites
will break down anything on the Moon’s surface, but the materials
Gonzalez is looking for should be far below the surface and protected
from this type of erosion.
The Iowa State astronomy professor even theorizes that since Mars and
Venus experienced asteroid collusions during the same time period and
fragments from those planets may also be on the Moon. He says the Moon
is strategically located within the inner solar system to be a "collector
of debris."
"Meteorites are likely to contain uniquely preserved remains of these
planets that are not available elsewhere in the Solar System," Gonzalez
says. "In particular, terran meteorites on the Moon may provide a
substantive geological record for ancient Earth, corresponding to or predating
the period for which the earliest evidence of life exists."
Gonzalez and his colleagues have likened the Moon to Earth's attic, a
sort of deep-freeze repository for relics of the terrestrial dawn.
That attic, according to Gonzalez's study, could contain as much as 20
tons of terrestrial materials buried over a typical lunar area of about
40 square miles at the Moon's surface. These materials could contain geochemical
and biological information such as isotopic signatures, organic carbon,
biologically derived molecules and minerals and maybe even microbial fossils.
Most of the Earth materials located on the surface would probably be no
bigger than a few centimeters, but would prove scientifically valuable
at even smaller sizes.
"A fragment the size of a grain of salt will be enough to get useful
data out of," Gonzalez said.
Since Gonzalez's theory was first published last spring, it has developed
a near interest among many about actually returning to the Moon.
Gonzalez and his research team feel that a return trip to the Moon is
warranted to help learn about the origin of life on the Earth. A remote
vehicle or astronauts could undertake the mission.
"We would suggest using a rover to search near fresh caters on the
Moon for recently excavated material,” Gonzalez said.
"It's gotten people showing interest into going back to the Moon,"
he continued. "People can relate to the Moon. We see it every day
- it's part of our everyday experience. A lot of people would like to
go back there and this is a good excuse to do just that."
Around LAS
September 9-22, 2002
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