Mounting Evidence of Water Vapor Columns on Jupiter’s Moon Europa

The scientific community has suspected of the existence of water vapor columns on the Jovian moon Europe since the time of NASA’s Galileo mission (launched in 1989), although no indirect evidence was found until the past decade. Now, a new study from ESA and published in ‘Geophysical Research Letters‘ offers new evidence of the existence of water vapor columns on the distant Jovian moon

Europa, one of Jupiter’s four largest moons, has a surface that appears to be covered with reddish scars that intersect to form a zigzagging network. It’s an alien world as it gets, both above and beneath its enigmatic surface. Scientists say that if there is a place in the solar system that alien life exists, there’s a good chance that, that place it Jupiter’s moon Europa.

The water ice cap drilled by these marks is believed to be several kilometers thick and covers a vast, potentially habitable ocean underground. The “scars“, captured by NASA’s Galileo probe, are a series of elongated cracks open in its icy surface, evidence of mighty gravitational pull exerted by our Solar System’s largest planet. The ice breaks, water vapor is expelled to the surface.

The scars that Europa wears proudly on its surface are believed to be caused by the massive gravitational pull of Jupiter, which eventually ends up cracking the ice, leaving Europa with its famous marks.

The colors visible on the surface of the Jovian satellite are representative of the surface composition and size of ice crystals: reddish areas, for example, contain a higher proportion of components other than ice, whereas in blue-white areas it is relatively pure.

Scientists are eager to explore what lies beneath Europa’s thick ice sheet, something they can do indirectly by looking for evidence of activity from underground. This is precisely what the new study’s author Hans Huybrighs, has done.

Building on previous studies of the magnetic field conducted by the Galileo Mission, the new study led by the ESA researcher uses simulations to try to understand why fewer protons (positively charged subatomic particles) were recorded in rapid motion than expected in the vicinity of Europa during one of the flybys by the Galileo spacecraft.

At first, the researchers believed it was because Europa obscured the detector and prevented the tool from measuring the usually abundant, charged particles.

Instead, Huybrighs and his collaborators saw that part of this decrease in the number of protons was due to a column of water vapor ejected into space.

This column disturbed the thin atmosphere of Europa and the region’s magnetic fields, altering the behavior and prevalence of protons in the area. According to ESA, if those columns of water vapor really exist and cross the ice sheet of Europe, they would be a way to access and study the content of its inland ocean.

These expectations are of great importance to Juice, an ESA mission scheduled to launch in 2022, tasked with studying Jupiter and its icy moons. The mission will have the required equipment to directly sample particles within Europa’s water vapor columns and to detect them remotely to reveal the secrets of its vast and mysterious ocean.

The mission, which should reach the Jovian system in 2029, will study the potential habitability and subsurface oceans of three of the giant planet’s moons: Ganymede, Callisto, and Europa.

As this new study demonstrates, tracking neutral and charged particles around Europa is very promising for studying its atmosphere and its broader cosmic environment, which is precisely something that the Juice mission is tasked with doing.