The Jupiter Icy Moons Explorer has blasted off on an eight-year voyage from a spaceport in French Guiana. The European Space Agency’s mission to Jupiter will survey three moons that may have once hosted life. Europa, Callisto and Ganymede are frigid, ice-covered Jovian satellites three-quarters of a billion km from the sun, but they have vast liquid water oceans beneath their surfaces.

If hydrothermal vents – found on ocean floors all over Earth – exist, they may provide enough warmth for life to thrive in the darkness

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