The smooth plains are younger still with fewer craters. (solarviews.com)
The relatively few craters indicate that the icy crust has been relatively warm and mobile for at least a good part of Europa's early history. (britannica.com)
A spacecraft could study fresh rock from the parent's interior, Richardson notes, because few craters and little dust would have obscured the surface in 6 million years. (sciencemag.org)