The white material seen within this gully is believed to be dusty water ice in a Martian region called Dao Vallis, captured by NASA's Mars Reconnaissance Orbiter (MRO). Scientists believe dust particles within this ice act similarly to dust that falls on to glaciers on Earth, warming up in sunlight and causing subsurface pockets of meltwater to form.

On Earth, the dust that forms these pockets are called cryoconite, and the pockets are called cryoconite holes. These Earth-based pockets of water are often teeming with simple life, including algae, fungi and cyanobacteria. Scientists believe similar shallow pools of water could exist on Mars, and may also be excellent places to search for life on the Red Planet today.

This black-and-white image was captured by MRO using its HiRISE (High-Resolution Imaging Science Experiment) camera on May 10, 2009.

The University of Arizona, in Tucson, operates HiRISE, which was built by Ball Aerospace & Technologies Corp., in Boulder, Colorado. NASA's Jet Propulsion Laboratory, a division of Caltech in Pasadena, California, manages the Mars Reconnaissance Orbiter Project for NASA's Science Mission Directorate in Washington.

For more information, visit: science.nasa.gov/mission/mars-reconnaissance-orbiter