Almost 15 years have passed since NASA sent its Galileo spacecraft flying into Jupiter's outer atmosphere to die-eliminating the possibility of contaminating nearby Jovian moons with any traces of Earth bacteria.
But the probe never directly encountered any of that water - or so scientists thought at the time.
"The idea that Europa might possess plumes seems to be becoming more and more real, and that's very good news for future exploration", said Xianzhe Jia, a space physicist at the University of MI and the lead author of the new paper on the phenomenon. The research appears in the journal Nature Astronomy.
The implications could be enormous.
Ever since the Hubble Space Telescope detected Europa's plumes, scientists have been working under the assumption that the planned Europa Clipper spacecraft could collect more data on their contents.
The revelation has again emphasised the scientific consensus that Europa, which has a salty ocean twice the size of Earth's, could be home to extraterrestrial life. This new analysis adds backing to theories that an ocean of liquid salt water exists below the ice. Nutrients sprayed onto the ice by the nearby volcanic moon Io, the thinking goes, may sink down to the ocean floor and serve as food. For example, NASA's Cassini spacecraft sampled plumes from Saturn's ocean-bearing moon Enceladus that contained hydrogen from hydrothermal vents, an environment that may have given rise to life on Earth. But until now, solid evidence has been hard to come by.
The interpretation of those images has been debated; the images pushed the limits of Hubble's sensitivity, and sometimes the space telescope was unable to spot the plumes altogether.
Image: Jupiter's gravity is thought to cause the tidal heating. They analyzed and modeled the data to explain this discrepancy.
One ardent supporter of a mission to Europa, Texas Congressman John Culberson, broke the embargo on this news last week during a Congressional hearing on NASA's budget.
Jia used measurements from Galileo's magnetometer to seek out small perturbations in the magnetic field during the closest flyby.
"With the Hubble data in hand", Dr. Kivelson said, "we had an idea of how big a plume might be reasonable".
Their discovery not only suggests Europa's watery plumes really do exist, but are also frequent and widespread. Xianzhe Jia, the lead author of the study, told Mashable, "This is potentially great news for future exploration of Europa, because spacecraft may have a chance to directly sample materials that are linked to the subsurface ocean". "We can analyse the particles and the gases to get a detailed composition of Europa's interior".
The space agency is priming two probes, including one that will land on its surface, to explore the distant moon in detail within the next decade, the agency says.
As the Inquisitr reported earlier today, NASA announced a major update on Jupiter's icy moon. For years Culberson has advocated for both Europa missions, ensuring they are present and accounted for in multiple budget bills.
Flying at 6km (3.7 miles) a second Galileo made its closest ever flyby, shooting across the surface at an altitude of 200km (125 miles) when it detected something unusual. That would give it unprecedented access to visuals of plumes and the ability to taste of their water for salts, organic compounds, and other chemicals.