火星の塩水で生存可能なバクテリアが見つかる

NASA's Mars Reconnaissance Orbiter shows bright ripples line the topography in this region, formed within a past climate. Dark dunes and sand streaks (composed of basaltic sand) have moved and filled lower areas, pushed by more recent winds from the top towards the bottom of this image.

Трещины и ямки в Южном полушарии Марса.

This image covers many shallow irregular pits with raised rims, concentrated along ridges and other topographic features. How did these odd features form?
One idea is that they could be from sublimation of shallow lenses of nearly pure ice, but why do the pits have raised rims? They can't be impact craters with such fortuitous alignment and irregular margins. They aren't wind-blown deposits because there are many boulders, too big to be moved by the wind. There are younger wind-blown drifts on top of the pits, and there's no clear connection to volcanism.

Wind is one of the most active forces shaping Mars' surface in today's climate. The wind has carved the features we call "yardangs," one of many in this scene, and deposited sand on the floor of shallow channels between them. On the sand, the wind forms ripples and small dunes. In Mars' thin atmosphere, light is not scattered much, so the shadows cast by the yardangs are sharp and dark. (Note: The cutout is not map-projected, so approximate north is down). The University of Arizona, Tucson, operates HiRISE, which was built by Ball Aerospace & Technologies Corp., Boulder, Colo. NASA's Jet Propulsion Laboratory, a division of the California Institute of Technology in Pasadena, manages the Mars Reconnaissance Orbiter Project for NASA's Science Mission Directorate, Washington.