September 26, 2016

Is it windblown or not?

A Piece of Mars: This 480×270 m (0.30×0.17 mi) scene shows what are being called “ridges”. Were these ridges once dunes that have now been stabilized and eroded? They have some dune-like characteristics: nearly parallel crests, one slope is steeper […]
September 19, 2016

Light and dark

A Piece of Mars: This 0.96×0.54 km (0.6×0.34 mi) late winter scene is a study in contrast. The dark top half is uniformly rippled. This is the shady surface of the main windward side of one of Mars’ biggest dunes, […]
September 12, 2016

Shades and textures

A Piece of Mars: This 480×270 m (0.3×0.17 mi) scene shows the contact between two very different terrains. On the left is a bright surface with polygonal cracks (characteristic of periglacial terrain – this is at a high latitude). On […]
September 5, 2016

Eroded dune

A Piece of Mars: Barchan dunes on Mars have a characteristic crescent shape, with a steep slope (“slip face”) on the inside of the sharpest curve (see examples like this, this, these, or this). This image (873×491 m, or 0.54×0.31 […]