NASA Mars MRO HiRise Image: A Pedestal Crater

Credit: Nasa /JPL /University of Arizona

This HiRISE image shows what is termed a pedestal crater, so-called because the level of the surface adjacent to the crater is elevated relative to the surface of the surrounding terrain.

The raised surface has patterns and a general outline resembling what ejecta would look like after being thrown out from the crater by the impact.

This impact probably occurred at a time when the surface of the whole scene was at the level of the raised surface.

The ejecta landed on the part of this surface close to the crater. Erosion then removed material in the rest of the scene while the impact ejecta shielded the area around the crater, protecting the ground under it from eroding and keeping it high.

The eroded, or “missing”, terrain in the rest of the scene may have contained ice. Lobe shapes at the base of the raised ejecta and polygons (visible when zoomed in) on the surface both suggest the pedestal material may have, or may still, contain ice.

The pattern of ejecta is asymmetric around the crater, suggesting the impactor may have hit the ground traveling from the north-east.

Jupiter fireball captured on video by amateur astronomer

Jupiter fireball captured on video by amateur astronomer Texan George Hall. http://spaceweather.com

On September 10, amateur astronomer George Hall caught an impactor – likely a gravitationally captured asteroid or comet – vapourising in Jupiter’s atmosphere.

It is likely the impactor was quite large to produce such a visible result, but the numbers aren’t in yet.

The after effects will also be telling.

The largest impactors, such at the 1994 comet Shoemaker-Levy 9, leave black marks on Jupiter’s atmosphere.

Jupiter experiences a greater number of impactors than Earth since its mass provides a strong gravitational pull on passing objects.

Jupiter is even credited with clearing space that would otherwise be filled with Earth-bound debris.