Water plumes on Europa: Tasting an extraterrestrial ocean

Computer simulations of the plumes of liquid water that stream out of Jupiter's moon Europa show that the forthcoming space mission JUICE may offer an answer to the question as to whether the Jovian moon's subsurface ocean could harbour life. Hans Huybrighs comes to this conclusion in the doctoral thesis he has recently completed at the Max-Planck Institute of Solar System Physics and the Technical University Braunschweig, Germany, in collaboration with the Swedish Institute of Space Physics in Kiruna.

A deep ocean of liquid water is hidden under the icy surface of Jupiter's moon Europa. Life might have developed here, shielded from sunlight and curious observers from planet Earth. Peeping through the ice to find traces of this hypothetical life is easier said than done, especially when you realize that the ice could beseveralkilometres thick. In 2022 the European Space Agency (ESA) will launch its space mission JUpiter ICy moon Explorer (JUICE). The JUICE spacecraft will arrive at Jupiter and its icy moons in 2030 and on board will be the Particle Environment Package (PEP) developed at the Swedish Institute of Space Physics (IRF). New research shows that PEP, an instrument consisting of several particle detectors, will be able to "taste" the plume in different ways and shed some light on the contents of Europa's ocean.

Observations from the Hubble Space Telescope of Jupiter's moon Europa, made in recent years, have shown that water is erupting from Europa's surface.

"Europa's plumes are the most straight-forward way to taste its subsurface ocean," says Hans Huybrighs. "Flying through one of the plumes of water and taking samples of the material could be the easiest way to study Europa's ocean. JUICE will be the first mission that might be able to do this."