Mars Mystetry: Clues In New Photos

Data From Space Probe Indicates Water And A Complex Geologic Past

(AP)  New images from NASA's Mars Odyssey spacecraft provide the first direct evidence that a variety of processes created the layers of rock seen on the planet, suggesting a complex geological past.

The infrared images, released Wednesday, show areas of Mars marked by layered terrain previously known to scientists. The new images, however, show how different those layers are, suggesting they were deposited or later modified in different environments.

"The amazing thing that surprised me was that these wonderful layers, layer of rock, have very different physical properties," said Phil Christensen, lead scientist on the $300 million mission's camera system.

The images record variations in the temperature of the surface visible in the infrared. Since different materials warm and cool differently during the day, their corresponding heat signatures indicate their composition.

In one of the two new images, rocky layers in the Terra Meridiani region of Mars show up as white, or warm; loosely compacted dust cools more quickly and appears darker. At least four distinct layers of rock appear.

"The geology is just laid out there in full view for you to look at," said Christensen, who presented the new images at the American Geophysical Union meeting in Washington, D.C.

The differences could have been laid down in volcanic eruptions, by wind-blown sediments or in watery environments such as lakes. Christensen suggested the action of ground water percolating through the buried sediments could also account for the differences.





Earlier this week, researchers reported that sensing data from the Mars Odyssey spacecraft suggest that large deposits of water ice are buried just one to two feet below the planet's surface.

This boosts the possibility of life on the Red Planet and suggests there may be a source for drinking water and rocket fuel for future exploration, researchers report.

The ice is covered by a thin layer of dust and broken rock, the researchers say, but the signals suggest that 20 to 35 percent of the icy layer is water, filling the pores the soil.

Earlier studies had shown strong evidence that Mars was once covered with water. This lead to speculation about how a planet so covered with water could lose its oceans. The new studies suggest that the water drained downward until it was trapped as ice just below the protective layer of soil.

The presence of vast stores of water could simplify exploration of Mars. Astronauts could use the water to drink or to grow crops in shelters. The water could also be split apart chemically, providing oxygen and hydrogen for rocket propellant.

Proof that water is common on Mars also strengthens speculation that the planet could harbor some microbial life forms. Water is considered essential for the evolution of life and some scientists believe they have evidence, from a Martian rock, that the planet once had life.

Jim Bell of the Department of Astronomy, Cornell University, said in Science that locating the subsurface water could guide Martian explorers in the selection of landing sites.

Bell called the discovery, coming just a month after the orbiting Mars Odyssey craft began its mapping mission, "stunning."