Life on Mars might lurk in long gullies carved by liquid water underneath a dirty but protective blanket of snow, astronomers said on Wednesday.Astronomers first observed the Martian gullies three years ago, but did not know what created them. Philip Christensen, a professor at Arizona State University, has now analysed images from NASA’s Mars Odyssey spacecraft and said they may have been gouged out by melting snow.‘‘I think we have discovered remnants of snowpacks on Mars that in the recent past have melted,’’ Christensen said at a briefing at NASA headquarters.‘‘I think if you were to land on one of those and stick a shovel in the ground, you’d be shovelling snow,’’ he said. ‘‘And if life ever existed on Mars, I can’t think of a more exciting place to possibly go and look.’’In Christensen’s scenario, the upper layer of snow is loaded with dust and is therefore less easily melted than snow without those impurities. Only a few inches beneath that snowpack, a lower layer of snow can melt without evaporating.It forms the gullies at the edges of craters on Mars, much as melting snow might form gullies on earth’s mountainsides. The gullies Christensen’s team observed were in the mid-latitudes of Mars, rather than at the poles, which is where other astronomers have focused the search for water. The quest for liquid water on Mars is a long-standing one, because water is seen as a prerequisite for life as it is known on Earth. (Reuters)
