How old is Europas surface, and how do we know?
Galileo imaging shows that Europa’s surface is sparsely cratered, meaning that the surface is probably young. Simulations of comet and asteroid orbits indicate that it is primarily comets which slam into Europa and the other Galilean satellites. From the modeled and observed numbers of comets in the vicinity of Jupiter today, estimates can be made for the surface age of Europa based on the number and sizes of the moon’s impact craters. By this method, Kevin Zahnle and coworkers estimate that Europa’s surface has an average age of about 50 million years (plus or minus a factor of five uncertainty). This is a blink of an eye by geological standards.
