Reynolds (crater)

Reynolds is an impact crater on Mars, located in the Mare Australe quadrangle at 75.1°S latitude and 157.9°W longitude and is in the southernmost portion of Terra Sirenum.

It measures 91 kilometers in diameter and was named after British physicist Osborne Reynolds.

It freezes out directly onto the surface of the permanent polar cap, which is made of water ice covered with layers of dust and sand.

By the time temperatures rise in the spring, the frost layer has become a slab of semi-transparent ice about 3 feet thick, lying on a substrate of dark sand and dust.

When it finds a weak spot, the gas escapes and blows out the dust.

Reynolds crater showing streaks from defrosting, as seen by CTX camera (on Mars Reconnaissance Orbiter). Layers are also visible. Note: this is an enlargement of the previous image of Reynolds crater from the table. Streaks are caused by pressurized carbon dioxide blowing out dust that is blown by the wind into streaks.
Reynolds crater showing layers and dark spots from defrosting, as seen by CTX camera (on Mars Reconnaissance Orbiter). Area is covered by frost, when the frost disappears the underlying dark ground is exposed. Layers are also visible. Note: this is an enlargement of the image of Reynolds crater shown above.