Shiny Mars pebbles intrigue NASA

NEW YORK, Feb. 20 (UPI) -- NASA scientists are pondering some tiny, shiny pebbles the Mars rover Opportunity picked up.

Since landing Jan. 25, Opportunity has been exploring the same small crater and one intriguing find, in the middle of the vast plain Meridiani Planum, is the small pebbles, many almost perfectly round, scattered over the surface.

The rover also saw these pebbles, about the size of BB's, embedded in an outcrop of bedrock it cruised past last week, the New York Times said.

Opportunity gouged a trench about a foot and a half long, six inches wide wide and four inches deep on Monday. It then spent three days examining the trench with a camera and two other instruments at the end of a mechanical arm.

Meanwhile, on the other side of Mars, Opportunity's twin, Spirit, will pause in the middle of its trek to a depression nicknamed Bonneville Crater to dig its own trench in the Martian soil.