August 31, 2002

In Man's quest to explore other planets in his solar system, the most burning issue has been the presence of water. At least from our scientific understanding, where there is water there is the potential for life. And where there is water there also can be human exploration and colonization.

So NASA sounded euphoric on May 28, 2002, when it announced that the 2001 Mars Odyssey spacecraft had surprised scientists by finding evidence of water on Mars. This proved the ancient Sumerian texts to be true when they described Mars as a watery planet.

More recently, in 1887, the Italian astronomer Schiaparelli observed what he termed canali (Italian for "channels") on Mars. This was misunderstood in the 20th century by Percival Lowell to mean "canals," and a whole controversy ensued about whether intelligent life on Mars had built canals to bring water from the ice caps. Lowell was later discredited, especially since the 1965 data from Mariner IV showed little surface water or ice on Mars.

	In this false-color map of Mars, soil enriched in hydrogen-containing water is indicated by deep blue. [Source: the neutron spectrometer onboard NASA's 2001 Mars Odyssey spacecraft.]

However, newer technology on the Odyssey spacecraft has detected telltale signs of water ice in the upper meter (three feet) of soil in a large region surrounding the south pole (see image at right) . Scientists have estimated that there is enough subsurface water ice there to fill Lake Michigan twice over.[1] There are also signs of water ice in the northern hemisphere, but none has been detected at the pole yet, since the Martian winter's frozen carbon dioxide covering hides the presence of water. And there may be more, for the measuring devices could probe only up to three feet below the surface.

"The subsurface ice detected by Odyssey," writes Dr. James F. Bell, a professor of astronomy at Cornell University, "may represent only the tip of an iceberg frozen underground."[2]

The discovery of water ice on Mars supports theories that early in its history Mars was wet and warm. For a long time now, scientists have believed that the canali observed by Schiaparelli are the result of water erosion.

There is also evidence that Mars once had a much thicker atmosphere, thick enough to seal in the sun's warmth. This evidence resurrects hopes that life did evolve on Mars and that some forms may still be alive today. Most likely, these life forms migrated with the water into the interior and are warmed by the planet's core.[2]

Dr. Bell says that the most important long-term implication of water on Mars is that it could be "a wonderful natural resource for the first explorers."[3]

Now that water has been located on Mars, can exploration be far behind?


References:

1. Science at NASA

2. Chang, Kenneth, "Scientists Measuring Martian Ice Detect Oceans' Worth" NY Times, May 28, 2002.

3. Mars discoveries key to future exploration?


For more information, see

Science at NASA

Mars Discoveries