Scientists recently presented fresh evidence of the possibility of water having once flowed on Mars. A nasa spacecraft currently orbiting Mars has captured photographs that depict equatorial ridges on Mars that could have been formed by running water.

Geologists believe the ridges were created through chemical changes caused by the flow of a fluid, almost definitely water, through a fissure in the rock. The study was recently published in the journal Science (Vol 315, No 5805) in December. Though not the first evidence of water on Mars, this brings fresh hope for the discovery of life outside Earth. Scientists are not sure how long ago water was present on the planet, but they trace its presence back to a long time. Attention now turns to looking for fossils of simple organisms.