Confirmed: Mars Like Earth

Measurements of Mars' spin axis, coupled with similar data from the Viking missions, confirmed suspicions that Mars has a dense core much like Earth.

By Kenneth Chang
ABCNEWS.com

Mars has clouds. A molten core much like the Earth’s center swirls within. Water used to flow along its surface. Long, long ago, Mars may have been much like Earth. NASA scientists this week publish their first results from the Mars Pathfinder mission, elaborating on speculations tossed out at earlier press conferences. The shape and mineral content of the Martian rocks “all appear consistent with a water-rich planet that may be more Earth-like than previously recognized, with a warmer and wetter past in which liquid water was stable and the atmosphere was thicker,” the researchers write. The findings, which appear in a series of articles in Friday’s issue of the journal Science, don’t offer any Mars-shaking bombshells, just scientific rigor to initial pronouncements. Whatever Mars might have once been like, it is no longer.

Chill of the Red Planet Temperatures during Pathfinder's stay ranged from -104 degrees Fahrenheit all the way up to -17 degrees. The Martian atmosphere is 150 times thinner than ours. The surface is bone dry. Just as forecasted. “There aren’t any big surprises,” said Tim Schofield, team leader for Pathfinder’s mini-weather station. The conditions were similar to what Viking I encountered two decades ago 525 miles to the northwest. During the Martian autumn day, waves of warmth bubbled off the Martian surface upward into the sky so that the temperature at the lowest thermometer might be 30 degrees hotter than the one located 2 feet higher. The scientists also found that light winds consistently blew through the site, south and downhill during the night; uphill during the day. (Much like on Earth where sea breezes blow inland during the day and out to sea at night.)

Those Nasty Dust Devils And they also saw “dust devils”—micro-hurricanes a few hundred yards apart and a few miles high—pass by the lander. Measurements of Mars spin axis, coupled with similar data from the Viking missions, confirmed suspicions that Mars has a dense core much like Earth instead of being uniform throughout like the Moon. “Now we know that,” says William Folkner of NASA’s Jet Propulsion Laboratory, one of the participating scientists on the mission. More controversial still are the rocks and soils. Chemical analysis of five of the rocks visited by the microwave oven-size Sojourner rover indicates they’re all of the same type. “That’s kind of a surprise,” says Harry McSween, geology professor at the University of Tennessee and member of the Pathfinder science team. One of the reasons NASA chose the plain called Ares Valles is that it appears to have been carved by huge ancient floods—which presumably would have carried along a wide range of rocks. “As near as we can tell,” McSween says, “they’re all the same” On the other hand, scientists on the rover team assert that they see in the photos water-rounded pebbles on the ground and that some of the stones may be cemented-together pebbles, hinting at a much wider range of minerals. Additional Pathfinder results are expected to be announced at next week’s American Geophysical Union meeting in San Francisco.