Do you think there might be life on other planets?

With the recent release of several movies featuring aliens in lead roles (Contact, Men in Black, Independence Day), the groundbreaking achievements of the Mars Pathfinder Mission, and the concurrent celebration of the 50th anniversary of the "Roswell Incident", it's not surprising that so many people are once again asking the big question, "Are we alone?".

Much of the newfound interest in the possibility of life of other planets can be credited to the recent discovery of 4.5 billion-year-old Martian meteorite, ALH84001. A team of scientists, headed by Dr. David McKay, found microscopic structures in the meteorite that resemble bacteria found here on Earth. Mineral grains and organic chemical compounds were also observed near these structures that are similar to those found in association with certain bacteria on Earth. Scientists believe that the now famous chunk of rock was dislodged from the surface of Mars 16 million years ago by an enormous asteroid impact. The rock then travelled through space for several years before falling to earth as a small meteorite in Antarctica 13,000 years ago.

To date, the Martian meteorite is the best evidence we have for the existence of life on another planet. Part of the problem with searching for other life forms may be the fact that we don't necessarily know what we're looking for. Our standard concept of "life" is based on carbon and water. But as Dr. David Grinspoon states, "We simply do not know if that is the only chemical system that can make life, because the only example of a biosphere we have is our own."

Submitted by Bianca (Canada)
Submitted by Erica (Alabama, USA)
Submitted by Billy (Iowa, USA)
Submitted by Amanda (Pennsylvania, USA)
(September 2, 1997)

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