StarDate: Evidence Of Life In A Rock From Mars

FROM THE UNIVERSITY OF TEXAS McDONALD OBSERVATORY, AS HEARD ON KCBS RADIO WEEKDAYS @ 9:52 A.M., 7:35 P.M. & 2:52 A.M

STARDATE 6/6/14: There's no doubt that Mars was once much warmer and wetter than it is today — a fairly comfortable home for life. But whether anything ever actually lived there is still unknown. The orbiters, landers, and rovers that have explored Mars have found no solid evidence of life on the planet — either today or in the distant past.

Some hints of life may have been found in Mars meteorites. A team of scientists reported evidence of past microscopic life in a meteorite two decades ago. Most other scientists dismissed the idea. But the same team reported possible evidence of life in another meteorite early this year.

The meteorite was discovered in Antarctica in the year 2000. It was identified as a piece of Mars from its chemistry. The rock formed more than a billion years ago. It was blasted away from Mars by an impact, and it landed on Earth 50,000 years ago.

The scientists studied the rock's interior with an electron microscope. They found tunnels through carbon-rich minerals, as well as tiny beads of material that are also rich in carbon. The researchers say those features are consistent with features in Earth rocks created by living organisms.

The researchers say the features could have been created by other processes. But they could also mean that life was tunneling through Martian rocks in the distant past.

Look for Mars to the left of the Moon this evening, shining like a bright orange star. More about Mars and the Moon tomorrow.