Jupiter's Moon Europa May Have Water Plumes That Rise Up About 125 Miles (npr.org)

NASA's Hubble Space Telescope released new images Monday, which will be published in The Astrophysicial Journal later this week, that show what appears to be plumes of water vapor erupting out of the icy surface of Jupiter's moon Europa. The discovery is especially intriguing as it means that the ocean below Europa's surface could be probed without having to drill through miles of ice. NPR reports: Europa is one of the most intriguing places in the solar system because it's thought to have a vast subterranean ocean with twice as much water as Earth's oceans. This saltwater ocean is a tempting target for astrobiologists who want to find places beyond Earth that could support life. The trouble with exploring this ocean is that the water is hidden beneath an icy crust that's miles thick. But if plumes are indeed erupting from Europa, a spacecraft could potentially fly through them and analyze their chemistry -- much like NASA's Cassini probe did recently when it sped close to Enceladus, a moon of Saturn that has small geysers. Scientists used Hubble to watch Europa's silhouette as the moon moved across Jupiter's bright background. They looked, in ultraviolet light, for signs of plumes coming from the moon's surface. They did this 10 separate times over a period of 15 months, and saw what could be plumes on three occasions. NASA says the plumes are estimated to rise up about 125 miles, and presumably material then rains back down onto Europa's surface. Using Hubble in a different way, scientists previously saw hints that salty water occasionally travels up to the moon's surface. In 2012, the telescope detected evidence of water vapor above Europa's south polar region, suggesting the existence of plumes that shoot out into space. The agency's Juno spacecraft is currently in orbit around Jupiter, but it isn't slated to take any observations of Europa.

Comments

Re:Presumably its ice particles , not water vapour

[Anonymous Coward]

Well, that is possible: https://en.wikipedia.org/wiki/Triple_point
Not saying that's what happening here, though.

Miles...

[wonkey_monkey]

Jupiter's Moon Europa May Have Water Plumes That Rise Up About 125 Miles

Ugh. I know the country that made the telescope that saw the plumes still insists on using miles, but can't we at least agree to outlaw imperial measurements for anything to do with space?

Especially spacecraft design and fuelling...

Re:Wat

[Rei]

Right. Because brief observations from an already present spacecraft that could help make critical design decisions about an upcoming multibillion dollar mission are an absurdity.

Look, we know Juno wasn't designed for this sort of mission and is not well equipped or positioned for it. But if researchers determine that its observations could help pinpoint more details of the plumes, then yes, they damn well should regardless of whether "tomhath at slashdot" considers that to be "real science" (apparently some vague category that he doesn't even feel the need to expand upon -- apparently planetary scientists have been working on "fake science" all these years, who knew?).

Re:So how is it supposed to communicate?

[Rei]

I think you're confused. Plumes means "in space". The whole benefit of plumes is that you don't need to go under the ice at all, you can do flybies to collect ice particles, or have a lander observe and sample the plumes at the surface. The key is that it means a recent connection between the depths and the surface, and that would be huge for simplifying exploration.

We're nowhere near to being able to launching an ice boring / swimming probe. If I recall correctly the last thing I read on the subject, however, the most promising means for communicating with such a probe on an affordable mass budget was.... not communicating with it. Aka, having it fully autonomous - melting its way down, sampling/observing the ocean, then re-melting its way back to the surface - then and only then transmitting. The waiting period with no data would be stressful (as if it failed you'd never know why), but it could potentially be used on almost any icy solid body regardless of the ice thickness.

It's also possible that there's liquid water much closer to the surface than the global ocean. There are some inferred lakes at a depth of only a few kilometers, which is potentially short enough for a probe to maintain a fiber connection with the surface. And after JUICE and Clipper, we may well have found locations that are even shallower.