Astronomy Domine

A mysterious shiny coating found on rocks in many of Earth's arid environments could reveal whether there was once life on Mars, according to new research.

The research, published in the July edition of the journal Geology, reveals that the dark coating known as desert varnish creates a record of life around it, by binding traces of DNA, amino acids and other organic compounds to desert rocks. Samples of Martian desert varnish could therefore show whether there has been life on Mars at any stage over the last 4.5 billion years.

Comet Tempel 1, which created a flamboyant Fourth of July fireworks display in space last year, is covered with a small amount of water ice. These results, reported by members of NASA's Deep Impact team in an advanced online edition of Science, offer the first definitive evidence of surface ice on any comet. "We have known for a long time that water ice exists in comets, but this is the first evidence of water ice on comets," said Jessica Sunshine, Deep Impact co-investigator and lead author of the Science article. More information on NASA site

Via Eureka Alerts:

Recent evidence from the Huygens Probe of the Cassini Mission suggests that Titan, the largest moon orbiting Saturn, is a world where rivers of liquid methane sculpt channels in continents of ice. Surface images even show gravel-sized pieces of water ice that resemble rounded stones lying in a dry riverbed on Earth.