An artist’s rendition of a water vapour plume erupting from Europa. Photograph: Nasa/Esa/K. Retherford/SWRI
A Nasa probe that explored Jupiter’s moon Europa flew through a giant plume of water vapour that erupted from the icy surface and reached a hundred miles high, according to a fresh analysis of the spacecraft’s data.
The discovery has cemented the view among some scientists that the Jovian moon, one of four first spotted by the Italian astronomer Galileo Galilei in 1610, is the most promising place in the solar system to hunt for alien life.
If such geysers are common on Europa, Nasa and European Space Agency (ESA) missions that are already in the pipeline could fly through and look for signs of life in the brine, which comes from a vast subsurface ocean containing twice as much water as all the oceans on Earth.
Nasa’s Galileo spacecraft spent eight years in orbit around Jupiter and made its closest pass over Europa, a moon about the size of our own, in 1997. As the probe dropped beneath an altitude of 250 miles, its sensors twitched with unexpected signals that scientists were unable to explain at the time.
Now, in a new study, the researchers describe how they went back to the Galileo data after grainy images beamed home from the Hubble space telescope in 2016 showed what appeared to be plumes of water blasting from Europa’s surface.
They found that a sudden blast of water from the Jovian moon explained the Galileo probe’s strange measurements.