Hubble may have caught jets of water squirting out of a potentially habitable moon
September 29, 2016
Jupiter's moon Europa - a giant ice ball thought to hide twice as much liquid water as there is on Earth - just became an even hotter target in the search for aliens.
Scientists on Monday unveiled new photographs from NASA's Hubble Space Telescope, and they likely show "fingers" of water vapor squirting out of Europa's hidden ocean and into space.
The grainy Hubble photos, taken in 2014, suggest water plumes occasionally shoot 125 miles into space, then rain back down on the surface.
If true, this would be Hubble's second time catching Europa's water plumes since 2012.
Water vents would also make Europa, which is about the size of Earth's moon, an even more irresistible place to look for signs of extraterrestrial life.
"In a future mission, we could fly through those plumes and tell a lot about the chemistry and nature of the surface" and possibly the liquid ocean below, Bob Pappalardo, a planetary scientist at NASA's Jet Propulsion Laboratory who wasn't involved in the work, told Business Insider - all without having to drill through the moon's miles-thick ice shell.
But secretive water worlds like Europa are not alone; Enceladus around Saturn also sprays out water, and so does Neptune's moon Triton - likely because they all hide giant oceans.
"A decade or so ago, we had no idea there might be several global oceans within our solar system. Now that's becoming generally accepted," Pappalardo said. "Satellite oceans may be the most common habitats for life that exist in the universe."
However, Pappalardo - and even the researchers behind the new study - couldn't guarantee the new Hubble images actually reveal water plumes.
'I'm not pretty damn sure they are there'
Two of the best Hubble photos show why the scientists are hesitant to say what they see are water jets:
Those blotchy "dark fingers," circled in red, are the suspected water plumes.
Why are the photos so grainy and difficult to make out? It boils down to Hubble's capabilities, plus what the telescope took pictures of.
Hubble was about 400-500 million miles away from Jupiter at the time, and it was taking pictures of Europa's silhouette as it moved across the gas giant's surface:
A press release provided to Business Insider states this kind of photography is "at the limit of what Hubble can do."
"Trying to just image Europa with the Hubble Space Telescope clearly from Earth is challenging," Pappalardo said. "Trying to image the [shadow] of a plume, via the light of Jupiter, is a remarkably hard beat. There's essentially a lot of noise in the system."
NASA press materials about Hubble's probable second discovery of the water plumes (using a totally different method) lean heavily on the word "if," for example (our emphasis added):
"These plumes, if they do indeed exist, may provide another way to sample Europa's subsurface," Geoff Yoder, the associate administrator for NASA's Science Mission Directorate, said in the space agency's main release.