Best evidence yet for plumes on Europa

James Marshall
May 14, 2018

'These findings will help plan future missions to Europa, such as Nasa's Europa Clipper and ESA's Jupiter Icy Moons Explorer spacecraft, both of which are expected to arrive at Jupiter between the late 2020s and early 2030s, ' said a Nature summary.

We just didn't know about it until now.

Checking for the presence of the water plumes on Europa, the Jupiter's icy moon, is, thus, of utmost significance and is getting closer to being a real thing because a USA science team managed to rebuild a 3D model of one of the plumes, basing themselves on the data collected by Galileo probe.

New analysis of measurements taken by NASA's Galileo spacecraft over 20 years ago provides more evidence that water from an ocean beneath Europa's icy shell is shooting out into space via at least one large geyser.

The image at the head of this article is an artist's interpretation of what a plume of water vapor might look like blasting from Europa's surface. That Hubble data, however, wasn't definitive proof of erupting plumes because it's such a hard observation to make from Earth's orbit.

The photo on the left traces the location of erupting plumes observed by NASA's Hubble Space Telescope in 2014 and 2016 (inside the green oval). During that time, the spacecraft made 11 flybys of Europa, including one in which it came to within a few hundred kilometers of the moon's surface. So a team of USA astronomers went back and took a second look at data collected by the Galileo spacecraft during its eight-year stay in the Jovian system.

To study the plumes, the probe will not need to pass directly through them.

"These results provide strong independent evidence of the presence of plumes at Europa", the study reads.

Jia hopes this paper will inspire fellow researchers to keep looking at Europa's plumes. This indicates the existence of periodic jets of water emanating from the moon's interior. Then, data from the plasma wave instrument showed unusual emissions that could be associated with a high density of charged particles - just what you would expect to find near a speeding jet of salty water.

Europa is set to be explored by two different spacecraft in the next decade. They found that Galileo had flown about 250 miles (400 kilometers) above the surface of Europa on December 16, 1997.

The results of the Clipper and JUICE missions, he continued, "could have huge implications" - nudging us Earthlings closer to understanding whether we are alone.

Researchers have long-thought that Europa's sea could play host to microbial life, but unless we get a sample of that water and analyze it, we'll never know if it's actually habitable.

Jupiter's moon Europa, as photographed by NASA's Galileo spacecraft.

However, according to Phillips, that kind of mission also has its limitations when it comes to discerning habitability. Some have suggested there might be a subsurface lake hiding between layers of Europa's thick ice sheets.

Near Enceladus' south pole, more than 100 individual geysers continuously blast water ice, organic molecules and other material far out into space - so far that this plume stuff forms Saturn's E ring.

"So, if plume material is collected, it may not be a direct sample of the ocean layer, but will 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?"

Other reports by Click Lancashire

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