Jupiter’s moon Europa continues to amaze and educate us about conditions in the “mid-range” region of the solar system. If you look at an image of Europa, you’ll notice right away that it appears to have jagged breaks in its icy crust, almost like a cracked egg. Yet, that surface is very smooth, which means it’s relatively young. There aren’t too many craters from impactors, and even the cracks look “iced over”.
Europa’s trailing hemisphere, as seen by the Galileo spacecraft in 1996. Courtesy NASA.
We’ve long suspected that Europa has a significant fraction of water hiding in an ocean under its frozen crust. That’s led scientists to dub it an ‘ocean world’ or a ‘water world’.
Data from missions as far back as Voyager and the Galileo spacecraft helped us suss out Europa’s true nature. The Juno mission, currently in orbit around Jupiter, has also imaged Europa, mostly from a distance. Its data add to the collection of amazing observations we’ve been able to make. Europa’s appearance and the presence of a possible subsurface ocean inspire many questions: Why is it so smooth? What else is happening there? Could Europa support life? Does it HAVE life now? ...