Science, Atmosphere | featured news

NASA's Curiosity rover results confirm that Mars has lost most of its atmosphere, on its way to becoming a cold, dry planet. In experimental results reported Monday at a European geoscience meeting in Vienna, Austria, a look at the Martian air by the $2.5 billion rover finds evidence that as much as 90% of the original atmosphere there has dissipated into space over the planet's lifetime. "It was still red, but it means that Mars once was a warmer, wetter world," says rover team scientist Sushil Atreya of the University of Michigan. "It was also a more habitable world, essentially four billion years ago."

The atmosphere of a relatively nearby extrasolar planet - just three times bigger than Earth - has been measured in a pioneering experiment.