A crater triplet on Mars

on 10 November 2020

Mars is covered in intriguing scars – some of the most prominent being impact craters. A particularly unusual example is shown in this new image from ESA’s Mars Express: an ancient triplet comprising not one but three overlapping craters.

The crater triplet is located in an especially old part of Mars’ southern hemisphere known as Noachis Terra. This region was heavily cratered during the Noachian era, an ancient time about four billion years ago in Mars’ history in which huge numbers of asteroids and comets flew inwards to crash into the planet's surface. Some of the features created by these collisions remain intact on Mars today and, as they formed during the very earliest days of the Solar System, are of particular interest to scientists seeking to know more about our planetary neighbour and its past.

Signs of chaotic Noachian processes and events are seen especially clearly in Mars’ southern highlands, which are peppered with old, time-worn craters. ESA’s Mars Express has imaged many craters in this region, from the severely eroded Greeley Crater, to the dune-patterned Neukum Crater, named after one of the founders of the Mars Express mission.

This image shows a triple crater found just east of a better-known feature named Le Verrier Crater, which spans nearly 140 km across. By contrast, the three depressions seen here are somewhat smaller; the largest measures 45 km across, and the smallest 28 km.

How would such a crater triplet form? One possible explanation – and that thought to be most likely – is that the impactor broke into three before hitting the ground, forming a crater trio upon impact. Another explanation could be coincidence: at different points in time, three separate impactors could have hit Mars’ surface in this location, creating a neat superposition of craters completely by chance.

To read more about the triple crater, please access this link.

Image credit: ESA/DLR/FU Berlin, CC BY-SA 3.0 IGO