Sunday, 04 Jan, 2009 Science

Puzzling Stone Circles Could Provide Evidence of Water on Mars


With the help of cameras installed on NASA's Mars Reconnaissance Orbiter, scientists observed stone circles on the red planet, which made them rethink about the ancient climate of Mars.

Together with his colleagues, Matt Balme, a researcher at the Open University in Milton Keynes, UK, managed to identify Elysium Planitia, which is an area located near the equator. Scientists noticed different rings of up to 23 meters, created of stones that were arranged by size into concentric bands.

On our planet such structures appear through repeated freezing and melting of ice, the stones, however, being arranged into layers. Water found in the earth below the stones freezes quicker than in surrounding soil. The escalating ice then drives the stones upwards. Layers arranged by size form from larger stones, which during the expansion of ice rise faster.

Scientists still don't know what arranges the material concentrically. They assume that in case a freeze-thaw mechanism was involved, the existence of liquid water near the surface would have been possible, which would mean that there was time when the climate on Mars was 40 to 60 C warmer than what conventional calculations state, informs New Scientist.

According to Peter Grindrod, professor at the University College London, the stone circles "would be an interesting target to look for evidence of past water on Mars".

Powered by

Add your comment:

antispam code