Fifteen years after the NASA probe burned up in Jupiter's atmosphere, newly analyzed magnetic and plasma data from the mission have bolstered evidence that Europa, the planet's ice-bound moon, is likely venting water into space.
This news is exciting for multiple reasons.
In those years, the Galileo spacecraft made eleven flybys of Europa, including one which brought it within a few hundred kilometers of the moon's surface.
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.
There are better tools now, better computational techniques, better computing. Jia said there was too little data to speculate at the moment, but that more research is being done.
The Clipper mission - now in the preliminary design phase - is projected to arrive at Jupiter sometime around 2030. Now, a new study in Nature Astronomy not only proves they were right, but also confirms that it does something more awesome than they could have imagined: it shoots up out of the crust in big, lovely plumes.
"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, headed by University of MI space physicist Xianzhe Jia, was published in the journal Nature Astronomy.
Artist's illustration of Jupiter and Europa (in the foreground) with the Galileo spacecraft after its pass through a plume erupting from Europa's surface. This image is from NASA, ESA, and K. Retherford. Jia's team pulled that data as well, and it also appeared to back the theory of a plume.
Whereas Galileo didn't know that it was flying through a plume and was incapable of collecting material from the plume, Europa Clipper will be able to gather material from plumes if it can fly through them.
"One of the locations she mentioned rang a bell".
"If plumes exist, and we can directly sample what's coming from the interior of Europa, then we can more easily get at whether Europa has the ingredients for life", he added.
The Galileo data were unique because the magnetometer was trying to detect changes in Europa's magnetic field as the probe approached the moon, like a boat going through water and creating waves. But Jia and his team wanted to make sure.
When they examined the information gathered during that flyby 21 years ago, sure enough, high-resolution magnetometer data showed something odd. And there it was on Europa - a brief, localized bend in the magnetic field that had never been explained.
Jia's team then began to analyze the old data in earnest, feeding some of the old data into a new 3D computer model developed by his team at the University of MI. At the time, though, scientists were skeptical, as the plumes were at the very limit of Hubble's ability to see. This fortuitous happenstance is the best evidence of plumes to date, the study said. Before heading to a meeting of scientists working on the Clipper mission, a thought occurred to Dr. McGrath: "Gee, I really should check to see if any of them line up with any of the claimed plume detections", from Hubble. These are no longer uncertain blips on a faraway image.
Scanning the Canadian lakes for signs of basic microbial life could help scientists in the upcoming Clipper mission which will look for alien life on Europa.
From its orbit of Jupiter, Europa Clipper will sail close by the moon in rapid, low-altitude flybys. Philips noted that collected plume material might not even be a direct sample of ocean water, but it would still "yield important insights into the composition of materials within Europa, and the potential for habitability-could there be environments on Europa where life could survive?"
That's what the mission is after.