Since the earliest days of our solar system’s history, asteroid impacts have shaped the planets and contributed to their evolution. New research funded by NASA shows that Mars experienced ten times fewer giant impacts than some previous estimates.
The ancient surfaces of Mars, like those on the moon and Mercury, are covered with the scars of asteroid impacts. The largest and most ancient giant impact basin on Mars, called Borealis, is nearly 6,000 miles wide and encompasses most of the northern hemisphere of the Red Planet. A smaller giant basin called Hellas is 1,200 miles wide and five miles deep.