NASA spacecraft was sprayed by a geyser on Europa, scientists learn

A new look at old data isgiving scientists a fresh reason to view Europa, a moon ofJupiter, as a leading candidate in the search for life beyondEarth, with evidence of water plumes shooting into space.

A bend in Europa's magnetic field observed by NASA's Galileospacecraft during a 1997 flyby appears to have been caused by ageyser gushing through its frozen crust from a subsurface ocean,researchers who reexamined the Galileo data reported on Monday.

Galileo was passing some 200 kilometres(124 miles) aboveEuropa's surface when it apparently flew through the plume.

"We know that Europa has a lot of the ingredients necessaryfor life, certainly for life as we know it. There's water.There's energy. There's some amount of carbon material. But thehabitability of Europa is one of the big questions that we wantto understand," said planetary scientist Elizabeth Turtle ofJohns Hopkins University Applied Physics Laboratory.

"And one of the really exciting things about detection of aplume is that that means there may be ways that the materialfrom the ocean which is likely the most habitable part ofEuropa because it's warmer and it's protected from the radiationenvironment by the ice shell to come out above the ice shell.And that means we'd be able to sample it," Turtle told a NASAbriefing.

The research, headed by University of Michigan spacephysicist Xianzhe Jia, was published in the journal Nature Astronomy.

The findings support other evidence of plumes from Europa,whose ocean may contain twice the volume of all Earth's oceans.NASA's Hubble Space Telescope in 2012 collected ultraviolet datasuggestive of a plume.

NASA will get a close-up look from a new spacecraft duringits Europa Clipper mission that could launch as soon as June2022, providing a possible opportunity to sample plumes forsigns of life, perhaps microbial, from its ocean.

Europa is considered among the prime candidates for life inour solar system, but is not the only one. For example, NASA'sCassini spacecraft sampled plumes from Saturn's ocean-bearingmoon Enceladus that contained hydrogen from hydrothermal vents,an environment that may have given rise to life on Earth.

A bit smaller thanEarth's moon, Europa's ocean residesunder an ice layer 15 to 25 kilometres(10 to 15 miles) thick, with anestimated depth of 60 to 150 km (40 to 100 miles).