Hydrogen escape has contributed to Mars’s progressive aridity, but current hydrogen loss rates cannot explain inferred past water abundances. A three-dimensional model shows that during periods of increased axis tilt, hydrogen loss rates were up to ten times higher than present values.

We analysed the PM and XM data from the GRAIL mission. The PM phase started on 1 March 2012 and ended on 29 May 2012 (that is, 89 days) with the average altitude of roughly 55 km (ref. 5). The...

Analyzing gravity data collected by spacecraft orbiting other worlds reveals groundbreaking insights about planetary structures without having to land on the surface.