NASA's Mars Reconnaissance Orbiter (MRO) captured images of the new gully channel on Mars that didn't exist three years ago.
The new gully channel was spotted on a crater wall slope in the southern highlands of Mars and photographed May 25, 2013, using the orbiter's High Resolution Imaging Science Experiment (HiRISE) camera. No such gully was observed in photos taken of the same slope on Nov. 5, 2010.
"Although this pair of observations does not pin down the season of the event, locations HiRISE has imaged more often demonstrate that this sort of event generally occurs in winter, when liquid water is very unlikely," NASA wrote in a statement.
Though the gully looks like a water formation, NASA scientists speculate that it was carbon dioxide not water that created the gully. This is because gullies tend to form in winter months when the planet's temperature plummets.
Before-and-after HiRISE images at other sites demonstrate that this type of activity generally occurs in winter at temperatures so cold that carbon dioxide rather than water is likely to play the key role, according to Daily Mail.
The presence of water on Mars remains a debatable topic despite the discovery of formations attributed to the presence of water on the Red Planet. This includes dark streaks known as recurring slope lineae (RSL) that snake down crater walls during warmer weather.
Dark finger-shaped features found on Martian slopes that seem to disappear seasonally led researchers of a previous study to speculate that Mars may have free flowing water, at least during its warmer seasons.
"In HiRISE images, we see them forming, elongating and then fading over time," Lujendra Ojha, a graduate student at the Georgia Institute of Technology, told CNN. "That's why they're called seasonal -- they form and flow when the temperature is right."
Ojha and his colleagues used the MRO's spectrometer to look for chemical signatures on the formations. While they couldn't find direct evidence of water, they did find "something iron in nature" at the flows.
"We still don't have a smoking gun for existence of water in RSL, although we're not sure how this process would take place without water," Ojha said in a statement.
Recently, the HiRISE camera onboard the MRO also snapped a stunning photo of a Martian sand dune field covered in seasonal frost. The image of the sand dune field in a Southern highlands crater was acquired Jan. 24 when the Sun was just 5 degrees above the horizon.
