A long -lost moon could explain Mars’ weird shape and extreme terrain
Reported by Paul Sutter
Artist’s impression of Mars and its moons Phobos and Deimos, with Earth and its Moon in the background
© Getty
A long-lost moon could explain why Mars is so different from the other rocky planets in the Solar System. Today Mars has two tiny moons. But early in its history, the Red Planet may have had a much larger moon, which might be responsible for Mars’ weird shape and extreme terrain, Michael Efroimsky, an astronomer at the US Naval Observatory in Washington DC, proposes in a paper that has been submitted to the Journal of Geophysical Research: Planets and is available as a preprint via arXiv.