Venus craters

Radar image of the 69 km diameter crater Dickinson. A blanket of rough ejecta surrounds the crater, but most of the crater floor is relatively smooth and so appears dark, apart from the complex of hills near its centre. Craters like this are formed when a lump of solar system debris (about 30 times smaller than the crater) hits the surface at speeds of tens of kilometres per second. Impact cratering occurs at a known rate, and counting the number of impact craters on a large tract of terrain is a way of estimating the age of the surface.

Barton crater
Radar image of the 50 km diameter crater Barton. Instead of the central peak characteristic of many smaller craters on Venus, Barton is large enough to have a ring of peaks surrounding its centre.

Three craters in Lavinia Planitia
A composite perspective view made by draping a radar image onto a computer model of topography, showing a group of three impact craters in the Lavinia Planitia region of Venus. The nearest crater, named Howe, is 28 km in diameter. It has a well-formed central peak and is surrounded by a radar-bright (rough) blanket of ejecta.

Crater caused by oblique impact
A 50 km wide radar image showing an 8 km diameter impact crater. The asymmetric distribution of the bright ejecta suggested that this crater was formed by an oblique impact, by a 200 m object arriving from the south at a speed of maybe 20 km per second.

One of the smallest well-formed craters on Venus
A 40 km wide radar image showing how Venus’s dense atmosphere protects its surface from all but the largest impacts. Here a comet nucleus or small asteroid became broken into a cluster of at least four fragments that produced this complex impact crater. There are few well-formed impact craters on Venus smaller than this, because the impactors that could have produced them break up within the atmosphere and any small debris that reaches the ground strikes it too slowly to form craters.