Faint rumblings from deep beneath California's San Andreas fault may provide an early warning for significant earthquakes there.
Scientists from the University of California at Berkeley discovered the weak tremors during a long-term monitoring project on the San Andreas near Parkfield, Calif. The tremors lasted from four to 20 minutes and occurred far deeper in the crust than earthquakes.
This marks the first time these tremors have been detected along a boundary where segments of crust grind past each other, as they do along the San Andreas, according to the team, whose research appears in the current issue of the journal Science.
The Mars rover Spirit has found goethite - a mineral linked to water - during its exploration of the Red Planet.
Although both rovers have found such evidence in their nearly year-long treks, the goethite find is particularly important, NASA's Jet Propulsion Laboratory (JPL) said Monday. The mineral forms only in the presence of water, although it may be in liquid, ice, or gas.
On the other side of the planet, Opportunity has recently seen frost and clouds marking seasonal changes, according to a science team member of the Space Science Institute.
For years, scientists and environmentalists have pointed to farm runoff as a leading culprit for harmful blooms of algae off the coasts of North America. But they didn't have the evidence to convince some members of the farming industry that agricultural chemicals were triggering "red tides" or "dead zones" in coastal waters.