How Europa changed how we saw the solar system

On Monday, NASA is set to hold a press conference about some “surprising activity” on Jupiter’s icy moon of Europa. There’s no indication as to what that activity might be, other than it involves the Hubble Space Telescope, but it’s garnering more than one 2010 reference around the internet. Europa has always been a fascinating world that has challenged our view of the nature of the solar system.

First Glimpse

Europa was discovered by accident. Galileo Galilei turned his telescope to observe Jupiter on January 7th, 1610, when he made a startling discovery: the planet was accompanied by four small objects, and over the next several nights, he determined that these objects orbited the planet. He wasn’t alone in this observation: a German...