"Ries" is derived from Raetia, since the tribe of Raetians lived in the area in pre-Roman times.
Description
The depression is interpreted as a meteorite impact crater formed 14.808 ± 0.038 million years ago in the Miocene. The crater is most commonly referred to simply as Ries crater or the Ries. The original crater rim had an estimated diameter of. The present floor of the depression is about below the eroded remains of the rim. It was originally assumed that the Ries was of volcanic origin. In 1960 Eugene Shoemaker and Edward C. T. Chao showed that the depression was caused by meteorite impact. The key evidence was the presence of coesite, which, in unmetamorphosed rocks, can only be formed by the shock pressures associated with meteorite impact. The coesite was found in suevite from Otting quarry, but even before, Shoemaker was encouraged by the Nördlingen St. George's church built of locally derived suevite. The suevite was formed from mesozoic sediments shocked by the bolide impact. The Ries impact crater was a rampart crater, thus far a unique finding on Earth. Rampart craters are almost exclusively found on Mars. Rampart craters exhibit a fluidized ejecta flow after impact of the meteorite, most simply compared to a bullet fired into mud, with the ejecta resembling a mudflow. Another impact crater, the much smaller Steinheim crater, is located about west-southwest from the centre of Ries. The two craters are believed to have formed nearly simultaneously by the impact of a binary asteroid. Recent computer modeling of the impact event indicates that the impactors probably had diameters of about and , had a pre-impact separation of some tens of kilometers, and impacted the target area at an angle around 30 to 50 degrees from the surface in a west-southwest to east-northeast direction. The impact velocity is thought to have been about. The resulting explosion had the power of 1.8 million Hiroshima bombs, an energy of roughly 2.4 joules. The Ries crater impact event is believed to be the source of moldavite tektites found in Bohemia and Moravia. The tektite melt originated from a sand-rich surface layer that was ejected to distances up to downrange of the crater. Stone buildings in Nördlingen contain millions of tiny diamonds, all less than across. The impact that caused the Nördlinger Ries crater created an estimated of them when it impacted a local graphite deposit. Stone from this area was quarried and used to build the local buildings.
The landing site for Apollo 14 is a heavily craterized terrain, and one of the science goals of the mission was to sample ejecta from the impact that formed Mare Imbrium. Nördlinger Ries is an easily accessible, large impact crater, making it a convenient analog for lunar craters. Because of this, it was used as a location to train Apollo 14 astronauts, so that they would be able to investigate lunar impact structures and related rocks. Astronauts Alan Shepard and Edgar Mitchell, as well as Apollo 14 backup astronauts Eugene Cernan and Joe Engle trained here from August 10 to August 14, 1970.
