Europa
One other of Jupiter’s giant moons is Europa. Like Io, Europa orbits near Jupiter and has sizable moons orbiting past it. And so, like Io, Europa will get squeezed by fluctuating gravitational pulls, warming up its inside.
The results of this squeezing, although, is completely completely different on the 2 moons as a result of they’re made of various stuff. Not like rocky Io, Europa has a floor made largely of stable water ice. So when Europa will get squeezed by getting nearer to and farther from Jupiter, the friction created contained in the moon heats up the subsurface ice and turns it into liquid water.
The primary trace of a subsurface water ocean got here from NASA’s twin Voyager probes, which flew by the Jupiter system in 1979. The pictures they captured of Europa confirmed the smoothest floor within the Photo voltaic System, devoid of massive mountains, deep craters, or canyons. This hinted that the stable crust is likely to be on prime of a liquid layer, inflicting the crust to maneuver, break up and consistently resurface itself.
Different spacecraft that visited the Jupiter system, like NASA’s Galileo and Juno missions, have collected knowledge from Europa that add to our confidence that liquid water does exist beneath Europa’s floor. Below an icy shell about 30 kilometers (about 19 miles) thick, Europa could also be holding an ocean 70-100 kilometers (or about 40-60 miles) deep. Earth’s oceans, by comparability, solely stretch down about 11 kilometers (lower than 7 miles) at their deepest. Though Europa is smaller than Earth’s moon, its oceans are thought to comprise twice as a lot liquid water as all of Earth’s oceans and lakes mixed.
This was an thrilling discovery as a result of the seek for life past Earth focuses on locations the place liquid water can exist, since all recognized life types on Earth rely upon liquid water.
Europa’s oceans are additionally regarded as salty, suggesting they make contact with a rocky seabed. This bodes properly for the seek for life as properly, since underwater hydrothermal vents could possibly be a life-giving power supply.
In 2012, the Hubble Area Telescope noticed an enormous plume of water erupting from a geyser on Europa’s south pole. The picture it captured confirmed a plume about 200 kilometers (about 125 miles) excessive. NASA is planning to ship its Europa Clipper mission there in 2030, together with a particular mission goal to fly by Europa’s plumes. The European Area Company can be engaged on its Jupiter Icy Moons Explorer mission (a.ok.a. JUICE), which might examine Europa together with Ganymede and Callisto beginning in 2031. Each of those missions will be capable of spend years finding out Europa, probably answering lots of our most urgent questions on its tantalizingly liveable oceans.
