Posted on 10/17/2002 6:09:41 AM PDT by Pern
Neighboring Mars may look dry as a bone, but experts are finding evidence of life-sustaining water hidden below the planet's rugged terrain.
The quantities discovered so far by instruments aboard NASA's $300 million Mars Odyssey mission equal twice the volume of Lake Michigan.
Suspected for more than three decades, the watery findings compiled by the Odyssey after reaching its destination a year ago are a signpost of life on the Red Planet.
"We know water is essential for life. We know water has changed the face of Mars to a great extent," the mission's chief scientist, Stephen Saunders, told the World Space Congress on Wednesday. Houston is host to the nine-day gathering of space policy experts, aerospace engineers and scientists from 100 countries.
Mars promises to rank high on the list of destinations for future European and Japanese as well as NASA spacecraft, as much because of the similarities between the two planets as the differences.
Both planets formed about 4.5 billion years ago. Theorists believe Mars was awash with water until 3 billion years ago, when the climate changed. The Martian surface remains essentially unaltered since then.
Meanwhile, water has remained a force for change on the Earth. In addition, volcanoes and other geologic processes have so re-layered the terrain that the average age of the Earth's crust is only 100 million years.
"I suspect a lot of the record of what has happened on the Earth is preserved on early Mars," said Saunders.
Mars is too cold and its atmosphere too thin for water to exist as liquid on the planet's surface.
The first hint of a watery past was revealed in surface images taken by NASA spacecraft in the late 1960s and early 1970s. They included long winding channels and broad watersheds etched among the craters and rocks that scar the landscape.
Mars Odyssey was the first probe to reach the planet with instruments designed to scan just below the surface.
Earlier this year, the spacecraft found signs of subterranean water in the farthest reaches of Mars' southern hemisphere.
At the time, a layer of frozen carbon dioxide covered much of the northern hemisphere, preventing the measurements.
Now, the same watery pattern is emerging in the northern reaches as the Martian seasons change. Higher temperatures are melting the carbon dioxide, allowing the spacecraft to scan the terrain.
The latest findings are especially tantalizing because Mars Odyssey is equipped only to look for evidence of moisture within 7 feet of the surface. There may be much more awaiting discovery by more capable spacecraft.
Odyssey is building on the reconnaissance gathered by the Mars Global Surveyor, another camera-equipped NASA spacecraft that began orbiting Mars in 1997.
The two probes have uncovered other puzzling features that bolster a theory the Red Planet was once warm and overrun by water.
The features include what appear to be rock glaciers, formations on Earth that are made of ice encrusted by rocks and dirt. Another feature is the sharply grooved gullies in the sides of crater walls and cliffs that suggest subterranean water gushes periodically to the surface.
Hello....... EARTH is in space!
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