The pair of images show the channel forming on the wall of a crater in Mars’s Terra Siernum. Credit: NASA/JPL-Caltech/University of Arizona


A new gully has been seen on the surface of Mars.

By comparing two images taken with the High Resolution Imaging Science Experiment (HiRISE) on NASA’s Mars Reconnaissance Orbiter, scientists have found a new channel growing off of an existing ravine.

The two images were taken from above the planet’s southern highlands in November 2010 and May 2013. As the two are over one Martian year apart, the exact time at which this gully formed is uncertain.

“Before-and-after HiRISE pairs of images of similar activity at other sites demonstrate that this type of activity generally occurs in winter,” said a NASA spokesperson.

“This pair of images shows that material flowing down from an alcove at the head of a gully broke out of an older route and eroded a new channel.”

Despite the similarity to water formed ravines here on Earth, it is much more likely that carbon dioxide is responsible for those seen on Mars.

Even though there has been recent evidence that liquid water exists on the planet’s surface, during the coldest months of the Martian year this freezes, locking it away.

But, these low temperatures do mean that carbon dioxide can play much the same role that water does here on Earth, so is most likely responsible.


To read more about the changing face of Mars and how to observe the Red Planet at opposition this month, pick up the April issue of BBC Sky at Night Magazine, on sale now.