After bumping up against Barnacle Bill -- which got its name because
of barnacle-like structures that appeared in images beamed back to Earth
-- Sojourner activated its "sniffer," which allowed scientists
on Earth to determine the chemical composition of the rock. The rover was
programmed to spend 10 hours nosing up against Barnacle Bill.
Here the Rover turned up some surprises. Barnacle Bill was rich in silicon dioxide -- quartz, says Dr. Harry McSween. Quartz can come from a complex melting and remelting of rock -- "or of melting in the presence of a lot of water," he says. Silicon dioxide is also present in the Earth's rocks.
YOGIThe next stop for the 22-pound mobile geologist was a larger nearby rock, which JPL workers nicknamed "Yogi." The little rover had its first Martian fender bender and was stuck on Yogi for two days. An 11-minute delay between Earth controllers and the rover made navigation difficult at first. Yogi is a large basalt-type rock, similar to volcanic rock on Earth.
See the Rover in action as it scrapes Scooby Doo.
Scientists are finding rocks on Mars are much like rocks on Earth. One cone-shaped peak is marked by a whitish stripe, very reminiscent of what we might see in Arizona. Another hill shows four or five horizontal bands of rocks, like those in the Grand Canyon. Pathfinder scientists say the bands could be layers of sediment deposited by past floods and may have been formed by water in an ancient floodplain. Perhaps we are seeing evidence of multiple episodes of flooding, they say.
Many of the boulders are smooth and rounded, a sign that they had been eroded by fast-flowing streams. Very similar rocks are washed down from glacial lakes in Washington State and Iceland, they say.
There is still an enormous amount of water today, enough to cover the entire planet with an ocean half a mile deep, but it is frozen in the polar ice caps or locked in a thick layer of permafrost that scientists believe lies under the barren surface.
The WedgeThe little rover pops a
wheelie on the Wedge.
