STONE circles on Mars are prompting a rethink about the planet's ancient climate.
Using cameras on NASA's Mars Reconnaissance Orbiter, Matt Balme of the Open University in Milton Keynes, UK, and his colleagues mapped the Elysium Planitia, a region near the equator. They saw rings up to 23 metres across made up of stones sorted by size into concentric bands.
On Earth, similar structures form via repeated freezing and thawing of ice, but with the stones sorted into layers. Water in soil under stones freezes faster than in surrounding soil, and the expanding ice pushes the stones upwards. Larger stones rise faster, and so layers sorted by size form.
Using cameras on NASA's Mars Reconnaissance Orbiter, Matt Balme of the Open University in Milton Keynes, UK, and his colleagues mapped the Elysium Planitia, a region near the equator. They saw rings up to 23 metres across made up of stones sorted by size into concentric bands.
On Earth, similar structures form via repeated freezing and thawing of ice, but with the stones sorted into layers. Water in soil under stones freezes faster than in surrounding soil, and the expanding ice pushes the stones upwards. Larger stones rise faster, and so layers sorted by size form.
Full story on New Scientist
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