In 2013, plumes of liquid were imaged erupting from the surface of Jupiter’s moon Europa. These plumes came from geysers that sent freezing liquids up to sixty miles high.

In a new study appearing in Geophysical Research Letters, author Lorenz Roth goes through the Hubble Space Telescope’s archives looking for data that would allow them to measure the distribution of oxygen molecules around Europa. When looking at the trailing side of Europa, they find that oxygen appears in both H2O molecules (water) and molecular oxygen or O2. On the opposite, leading side, only molecular oxygen is present. This is interpreted to mean that geysers are only on the trailing side of Europa.

Like Earth’s moon, Europa is tidally locked, so the same face is always facing Jupiter, and the same sides are always facing into its motion and away from its motion. Why does this matter in the geysers? The paper hints at tidal interactions and more observations are needed.

More Information

NASA Goddard press release

“A Stable H2O Atmosphere on Europa’s Trailing Hemisphere From HST Images,” Lorenz Roth, 2021 September 13, Geophysical Research Letters