Dune field with hoarfrost in an ancient, eroded Martian crater
Dune field with hoarfrost in an ancient, eroded Martian crater
These Mars Express images of the southern part of Kaiser Crater show one of the oldest regions on the planet, Noachis Terra. The region gave its name to the Noachian Period, which lasted from 4.1 to 3.7 billion years ago. Numerous large craters are found here, slowly being levelled by erosion. Their rims are often barely recognisable, as seen here in the 30-kilometre-wide crater at the upper left of the image. On the right, a dune field with 'transverse dunes' is visible.