After years of debate, NASA researchers have zeroed in on the thickness of the Europa's ice shell. We first discovered that the Jupiter moon's surface looked icy in 1979, when Voyager 2 flew by.

"By understanding the sizes and shapes of craters on Europa and reproducing their formation with numerical simulations, we’re able to infer information about how thick its ice shell is." When you ...

See more of our trusted coverage when you search. Prefer Newsweek on Google to see more of our trusted coverage when you search. Saturn’s “Death Star”-like moon Mimas may have a boiling ocean under ...