Using the powerful High Resolution Imaging Science Experiment (HiRISE) camera, the orbiter snapped the area in both 2010 and in 2013. Before-and-after pictures record the appearance of an entirely new gully located on a crater-wall slope in Mars’ southern highlands, NASA said in a news release. Scientists think it likely was formed by carbon-dioxide frost.
According to NASA, gully or ravine landforms are common on the Red Planet, especially in its southern highlands.
The images show that material flowing down from an alcove at the head of a gully broke out of an older route and eroded a new channel, NASA explains. The dates on the images are more than a full Martian year apart, so the observations didn’t pin down the Martian season of the activity at the site.
Before-and-after HiRISE photos of similar activity at other sites show that this type of activity generally occurs in the winter, in temperatures so cold that carbon dioxide, rather than water, is the likely to play a key role, the space agency said.
Since the MRO first went into orbit around Mars in 2006, it’s been mapping the planets surface. The orbiter has a dish antenna 10 feet in diameter and a number of other scientific instruments, including a spectrometer for analyzing minerals, ground-penetrating radar, and an atmosphere sounding.