lunar image of the month

september: copernicus from lunar orbiter 2

The crater Copernicus is a relatively young one, having been formed by a massive impact nearly a billion years ago. It is also arguably the most spectacular visible from the Earth. Although other craters are larger or deeper or have more extensive ray systems, Copernicus scores well in all areas and has the benefit of a conspicuous position slightly north-west of centre as seen from the Earth.

This image, taken in 1966 by the probe Lunar Orbiter 2, shows its relief as no Earth-based photograph can. The crater is 93km (58mi) across and 3760m (12335ft) deep - nearly half the height of Mount Everest. It is no surprise that this type of crater is called a ring mountain.

To put the scale of the impact into perspective, the double crater in the foreground (due south from Copernicus) is Fauth (top, 12.1km / 7.5mi wide and 1960m / 6430ft deep) and Fauth A (9.6km / 5.9mi wide and 1540m / 5052ft deep). Meteor crater in Arizona, which was caused by the impact of an object estimated at 75000 tonnes, is a mere 1265 m / 4150 ft across and 175m / 575ft deep. It would compare with Fauth roughly as Fauth does with Copernicus.

Image: NASA.