On the surface, the clues strongly imply that Voyager 1 has passed the limit of our solar system's influence.

ENGADGET: AGU study says Voyager 1 has reached interstellar space, but NASA remains skeptical

There is a limit to the lifetime of these features: Europa's surface is relatively young, having been resurfaced by currently unknown processes some 50 million years ago.

BBC: Ice blades threaten Europa landing

And a 50mph speed limit is in place on much of the M4 in south Wales due to surface spray.

BBC: Flooding: Heavy rain could spark more floods, agency warns