August 10, 2009--The Mars rover Opportunity snapped itself "leaning in" for a closer look at Block Island, a meteorite recently found on Mars, in a new false-color picture released by NASA.

The red planet's largest known meteorite, Block Island is an iron-nickel space rock about 2 feet (0.6 meter) wide. Based on its size, scientists say the meteorite should have disintegrated on impact--unless Mars had a much thicker atmosphere when the object arrived. Denser air would have created more friction, slowing the rock's approach.

"Either Mars has hidden reserves of carbon-dioxide ice that can supply large amounts of carbon-dioxide gas into the atmosphere during warm periods of more recent climate cycles, or Block Island fell billions of years ago," rover team member Matt Golombek said in a statement.