Press cutting: Is this the water mark of life on Mars?
8 December 2006
Before-and-after images of gullies on the planet taken by Nasa's Mars Global Surveyor show liquid has flowed on the planet in the past five years.
It suggests geological activity could be heating water beneath the surface so that it is warm enough to flow for long enough to leave deposits behind.
This possibility is particularly exciting because water and a stable heat source are key precursors for the existence of life.
Dr Andrew Coates, of the UCL Mullard Space Science Laboratory, said: "It suggests there is some sort of geological heating process going on beneath the surface and that Mars is a more dynamic place than we had previously thought.
"Life can survive in very difficult situations so if there are places with liquid water under the surface with heating, it could mean there is life there now."
Nic Fleming, 'Daily Telegraph'