WASHINGTON, D.C.--The Opportunity rover has found strong
evidence that eons ago water flowed across Mars, pooled on the
surface, and then returned to the atmosphere, leaving behind a
thick layer of minerals leached from the land. "We've found our
ancient water on Mars," says rover science team member Harry
McSween of the University of Tennessee, Knoxville. At a press
conference at NASA headquarters here today, rover principal
investigator Steven Squyres of Cornell University ticked off the
evidence for a soaking wet Mars he and his team had developed
from Opportunity observations of the previous weeks. The new
findings don't prove that Mars ever sustained life or even that
Mars was ever as warm and wet as Earth has been. However, they
do mean that at least in one patch the size of Oklahoma, water
soaked the rock for age upon age, which is all that life could
ask for. Part of the evidence involves the structure of the
outcrop. The round balls 2 or 3 millimeters in diameter seen
weathering out of the rock, they