Saturn's moon Enceladus sprays an ocean into space through icy geysers

Enceladus is a small, brilliantly white moon of Saturn, and one of the most surprising places in the Solar System. NASA’s Cassini spacecraft discovered geyser-like jets of water vapour and ice particles shooting from its south polar region, blasting outward at around 800 miles per hour and forming a plume that stretches hundreds of miles into space.

The jets vent through four long parallel fractures nicknamed the tiger stripes, each roughly 84 miles long, that score the moon’s southern terrain. Tracking how Enceladus wobbles on its axis and bends Cassini’s flight path, scientists concluded the plumes are fed not by isolated pockets but by a global ocean of liquid salty water sealed beneath an icy shell tens of kilometres thick.

Some of that water is even thought to react with rock at hydrothermal vents on the seafloor. That combination of liquid water, warmth and chemistry is exactly what makes this frozen moon one of the leading places astrobiologists hope to search for life beyond Earth.