Unusual circles spotted on Mars

By Dean Murray via SWNS

Scientists are scratching their heads after circles were spotted on Mars.

Scientists at NASA have reported "unusual" sand dunes on the Red Planet, which they say are "almost perfectly circular."

The space agency's Mars Reconnaissance Orbiter (MRO) spotted the shapes as it studied how frost thaws at the end of Martian winter.

NASA said: "Sand dunes of many shapes and sizes are common on Mars. In this example, the dunes are almost perfectly circular, which is unusual.

"They are still slightly asymmetrical, with steep slip faces on the south ends. This indicates that sand generally moves to the south, but the winds may be variable.

"This is part of a series of images to monitor how frost disappears in the late winter; this observation appears to be free of frost."

A previous image shows when the surface was covered by frost.

Earlier this year, the orbiter reported what looked like the face of a bear on the barren surface.

That quirky image was taken in December from a height of 251 km, with NASA saying: "A Bear on Mars? This feature looks a bit like a bear’s face. What is it really?"

Mars Reconnaissance Orbiter has been orbiting and studying Mars since 2006.

The spacecraft is designed to study the geology and climate of Mars, provide reconnaissance of future landing sites, and relay data from surface missions back to Earth.