In early 2015 astronomers spotted water vapor shooting out of cracks on Saturn's moon Enceladus, confirming long-held suspicions of an ocean of liquid water deep beneath the ice. Soon after, a separate team saw signs of an ocean sloshing within Ganymede, the largest of Jupiter's icy moons. More recently, NASA presented the best evidence yet for liquid water on Mars. It now looks like the solar system is awash with this key ingredient for life. A total volumetric estimate of the confirmed oceans alone adds up to 50 times more water than is found on Earth—a figure that could continue to surge.

Graphic by Amanda Montañez