Hubble Discovers Water Plumes Erupting from Europa

by Jason Major on December 12, 2013

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UV observations from Hubble show the size of water vapor plumes coming from Europa's south pole (NASA, ESA, and M. Kornmesser)

UV observations from Hubble show the size of water vapor plumes coming from Europa’s south pole (Artist’s impression. Credit: NASA, ESA, and M. Kornmesser)

It’s been known since 2005 that Saturn’s 300-mile-wide moon Enceladus has geysers spewing ice and dust out into orbit from deep troughs that rake across its south pole. Now, thanks to the Hubble Space Telescope (after 23 years still going strong) we know of another moon with similar jets: Europa, the ever-enigmatic ice-shelled moon of Jupiter. This makes two places in our Solar System where subsurface oceans could be getting sprayed directly into space — and within easy reach of any passing spacecraft.

(Psst, NASA… hint hint.)

The findings were announced today during the meeting of the American Geophysical Union in San Francisco.

“The discovery that water vapor is ejected near the south pole strengthens Europa’s position as the top candidate for potential habitability,” said lead author Lorenz Roth of the Southwest Research Institute (SwRI) in San Antonio, Texas. “However, we do not know yet if these plumes are connected to subsurface liquid water or not.”

The 125-mile (200-km) -high plumes were discovered with Hubble observations made in December 2012. Hubble’s Space Telescope Imaging Spectrograph (STIS) detected faint ultraviolet light from an aurora at the Europa’s south pole. Europa’s aurora is created as it plows through Jupiter’s intense magnetic field, which causes particles to reach such high speeds that they can split the water molecules in the plume when they hit them. The resulting oxygen and hydrogen ions revealed themselves to Hubble with their specific colors.

Unlike the jets on Enceladus, which contain ice and dust particles, only water has so far been identified in Europa’s plumes. (Source)

Rendering showing the location and size of water vapor plumes coming from Europa's south pole.

Rendering showing the location and size of water vapor plumes coming from Europa’s south pole.

The team suspects that the source of the water is Europa’s long-hypothesized subsurface ocean, which could contain even more water than is found across the entire surface of our planet.

Read more: Europa’s Hidden Great Lakes May Harbor Life

“If those plumes are connected with the subsurface water ocean we are confident exists under Europa’s crust, then this means that future investigations can directly investigate the chemical makeup of Europa’s potentially habitable environment without drilling through layers of ice,” Roth said. “And that is tremendously exciting.”

One other possible source of the water vapor could be surface ice, heated through friction.

Cassini image of ice geysers on Enceladus (NASA/JPL/SSI)

Cassini image of ice geysers on Enceladus (NASA/JPL/SSI)

In addition the Hubble team found that the intensity of Europa’s plumes, like those of Enceladus, varies with the moon’s orbital position around Jupiter. Active jets have been seen only when Europa is farthest from Jupiter. But the researchers could not detect any sign of venting when Europa is closer.

One explanation for the variability is Europa undergoes more tidal flexing as gravitational forces push and pull on the moon, opening vents at larger distances from Jupiter. The vents get narrowed or even seal off entirely when the moon is closest to Jupiter.

Still, the observation of these plumes — as well as their varying intensity — only serves to further support the existence of Europa’s ocean.

“The apparent plume variability supports a key prediction that Europa should tidally flex by a significant amount if it has a subsurface ocean,” said Kurt Retherford, also of SwRI.

(Science buzzkill alert: although exciting, further observations will be needed to confirm these findings. “This is a 4 sigma detection, so a small uncertainly that the signal is just noise in the instruments,” noted Roth.)

“If confirmed, this new observation once again shows the power of the Hubble Space Telescope to explore and opens a new chapter in our search for potentially habitable environments in our solar system.”

– John Grunsfeld, NASA’s Associate Administrator for Science

Read more: Hydrogen Peroxide Could Feed Life on Europa

So. Who’s up for a mission to Europa now? (And unfortunately in this case, Juno doesn’t count.)

“Juno is a spinning spacecraft that will fly close to Jupiter, and won’t be studying Europa,” Kurt Retherford told Universe Today. “The team is looking hard how we can optimize, maybe looking for gases coming off Europa and look at how the plasma interacts with environment, so we really need a dedicated Europa mission.”

We couldn’t agree more.

The findings were published in the Dec. 12 online issue of Science Express.

Sources: Hubble news releases (US and ESA)

Image credits:
Graphic Credit: NASA, ESA, and L. Roth (Southwest Research Institute and University of Cologne, Germany)
Science Credit: NASA, ESA, L. Roth (Southwest Research Institute and University of Cologne, Germany), J. Saur (University of Cologne, Germany), K. Retherford (Southwest Research Institute), D. Strobel and P. Feldman (Johns Hopkins University), M. McGrath (Marshall Space Flight Center), and F. Nimmo (University of California, Santa Cruz)

About 

A graphic designer in Rhode Island, Jason writes about space exploration on his blog Lights In The Dark, Discovery News, and, of course, here on Universe Today. Ad astra!

letsjustdoit December 12, 2013 at 1:17 PM

This discovery is the most exciting news since I read that Europa may have an ocean. It also underlines the advantage of so many robotic missions to gain as much knowledge as possible before we start throwing humans everywhere. Keep it up NASA!

UFOsMOTHER December 12, 2013 at 4:18 PM

This is just fantastic liquid water because of the gravity of Jupiter tugging on this huge moon , I think this is where we will find life beyond Earth the quicker we probe there for life the better and if there is an opening in the ice it makes it much easier than drilling miles of ice before getting to the water so lets get going NASA before the Chinese beat us to it ..

Kawarthajon December 13, 2013 at 9:40 AM

No need for a robotic mission to drill under the surface to access the water – just wait til the moon is as far away from Jupiter as it gets and then scoop the water out of the air, along with the fish analogues that live under the surface. Imagine their surprised expressions being frozen for ever as they are jetted out of the warm ocean into cold dark space.

InTheory December 13, 2013 at 9:59 AM

Imagine how easy it would be to drop a rover or two near the source of the plumes and see what might be sitting on the ice. No need for subs or ice drills. On top of that, the low escape velocity would make getting samples back a relatively simple job.

ethanol December 13, 2013 at 11:26 AM

Why is europa’s lower appendage censored in the second picture? We are all adults here.

editor December 13, 2013 at 11:57 AM

Breaking News: China launches return sample mission probe to Europa to test for life; beats United States to it.
Scared ‘ya, huh? Now get to work and build a probe. There’s life in them thar hills!

William Sparrow December 14, 2013 at 9:45 PM

Landing a rover on the Moon 44 years after the U. S. had men walking on it is a far cry from the probe mission you envision for China. Baby steps….

Squishhhhug December 13, 2013 at 1:20 PM

Cool, it sort of looks fake, but only with black in the background. very interesting. There has to be some sort of sea life deep down. I find this more interesting than mars at the moment, because who knows what kind of life is deep down ?? And what it can do for creation and affect disease and such. Has there been a drilling probe created yet ??

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