Nasa’s Europa Clipper spacecraft will investigate whether an icy moon of Jupiter can support alien life

Discovering extraterrestrial life would be one of the most profound scientific and philosophical revelations that our species has ever made. But such a big discovery won’t come easy. Our starting point is to first search other worlds for signs of habitability, that is, the potential for life to exist.

Nasa is doing just that: launching a spacecraft on October 10 to Europa, a moon of Jupiter holding twice the water of all Earth’s oceans combined. Europa’s...