Published: Tue, May 15, 2018
Research | By Raquel Erickson

New evidence raises hope of finding life on Jupiter's Europa moon

New evidence raises hope of finding life on Jupiter's Europa moon

Margaret G. Kivelson, an emeritus professor of space physics at U.C.L.A. who was the principal investigator for Galileo's magnetometer, was at Dr. McGrath's talk.

That's when the University of Michigan's Xianzhe Jia and colleagues chose to revisit those archival data and see what kinds of nuggets they could find.

A fresh look at data from a 1997 flyby of Jupiter's moon, Europa, suggests that NASA's Galileo spacecraft flew directly through a watery plume, raising hopes of probing the jets for signs of life around the second planet from Earth.

During the years after Galileo, the Hubble Space Telescope has, from time to time, observed the Jovian system. 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. "The data is there, publicly available for nearly 20 years", Jia says. The 1997 flyby was close to the site of the repeat detection by Hubble.

Galileo carried a powerful Plasma Wave Spectrometer to measure plasma waves caused by charged particles in gases around Europa's atmosphere. Something was wrong: There was a three-minute "bend" where there shouldn't be.

"One of the locations she mentioned rang a bell". We realized we had to go back. Further Hubble observations in 2014 and 2016 identified candidate plumes close to Europa's equator - in both cases, in the middle of a 200-mile-wide (320 km) Europan "hotspot" discovered by the Galileo probe.

The evidence comes from data collected by the now-defunct Galileo spacecraft.

A rendering of how NASA researchers believe Galileo flew through plumes of water high above Europa. "This is very likely to be the result of a plume, making it the best direct evidence for such an occurrence yet".

"It's awesome how hard it is to anticipate something that just hasn't happened before", Kivelson said.

How could Europa host life?

Now, with two spacecraft and several independent instruments reporting similar findings, it's harder to deny that Europa is venting water vapour into space. Would it use the same chemistry to store and use energy? If it's confirmed, the finding could help immensely in the search for other forms of life in our solar system. And while NASA already has plans to explore Europa, this is the most heartening sign of life that planetary scientists have been waiting for.

Galileo launched in 1989 to examine the fifth planet from the Sun.

The Europa Clipper mission may launch as early as June 2022.

Xianzhe Jia, a planetary scientist at the University of MI, heard astronomers suspected the plumes sat on the moon's equator, but couldn't get a good look at them with the Hubble Space Telescope, he told NPR. That's because heat from the interior of the moon is being forced upward in the plumes.

One author of the study published this week was Xianzhe Jia, an associate professor in the Department of Climate and Space Sciences and Engineering at the University of MI.

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.

These results add to the body of evidence that Europa may have a global ocean tucked beneath its icy surface, just like Saturn's moon Enceladus. When Jia and his team sifted through the observations of plasma and magnetic wave fluctuations Galileo picked up on Europa, Jia and his team were able to confirm that, yes, the geysers did, in fact, exist. This would allow scientists a first look at the material inside Europa's ocean that's spewing through the icy crust and revealing whether Europa's ocean is habitable and supports life. The experiments showed Europa possesses an atmosphere. "That's what the mission is after".

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