National Air and Space Museum News Media Access

Cumulative crater frequency plots for MFF units, with ages inferred for those distributions. The Hesperian era on Mars ended at about 3.5 Ga (billion years).

This image illustrates a paper by Smithsonian scientists James R. Zimbelman and Stephen P. Scheidt, “Hesperian age for western Medusae Fossae Formation, Mars” scheduled for publication in the June 29 issue of the journal Science.