May 27 1998
From The Space Library
Images released at the American Geophysical Union meeting in Boston showed what scientists believed was the first evidence of ice on Mars outside of the planet's polar ice caps. The images showed a 30-mile-wide (48-kilometer-wide) crater containing a discolored area measuring about 12 to 18 miles (19 to 29 kilometers) across the bottom of the crater. Some scientists thought the discoloration indicated the presence of some sort of deposit, possibly frozen mud or sand, evidence that ice is present, or was present in the past. Others offered a different theory about the contents of the images: volcanic activity could explain the apparent deposit in the crater. The images, from Mars Global Surveyor, had 10 to 12 times better resolution than any previous image of the crater. Arizona State University researchers made another announcement regarding Surveyor's data; the Arizona researchers believed that a "concentration of a rust-colored mineral along the Mars equator indicates it once had boiling hydrothermal vents and perhaps huge lakes." The mineral, hematite, was the first clear evidence of widespread thermal activity on Mars. NASA officials added that the finding indicated that water "was once stable at or near the surface and that Mars had a thicker atmosphere in its early history, probably 4 billion to 6 billion years ago."
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