12 December 2013
Last updated at 16:03
Water spouts taller than Mt Everest appear to burst out of Europa when it is farthest from Jupiter
Water may be spouting from Jupiter’s icy moon Europa – considered one of the best places to find alien life in the Solar System.
Images by the Hubble Space Telescope show surpluses of hydrogen and oxygen in the moon’s southern hemisphere, say astronomers writing in Science journal.
If confirmed as water plumes, it raises hopes that Europa’s underground ocean can be accessed from its surface.
Future missions could probe these seas for signs of life.
Astrobiologists have said that, in theory, organisms could survive in the oceans of Europa, but feared the moon’s thick icy crust may be an impenetrable barrier to life.
In this new study, US physicists looked at images taken by Hubble in November and December of last year, as well as older images from 1999.
Signatures of water (blue) detected by Hubble are overlayed on an image of Europa
In two distinct southern regions, they saw evidence of water being broken apart into hydrogen and oxygen – revealed by ultraviolet light signatures.
“They are consistent with two 200km-high (125-mile-high) plumes of water vapour,” said lead author Lorenz Roth, of Southwest Research Institute, San Antonio, Texas.
These giant geysers appear to be transient – they arise for just seven hours at a time.
They peak when Europa is at its farthest from Jupiter (the apocenter of its orbit) and vanish when it comes closest (the pericenter).
This means that tidal acceleration could be driving water spouting – by opening cracks in the surface ice, the researchers propose.
They say the vapour jets may be like those seen on Saturn’s moon Enceladus – with high-pressure emissions escaping from very narrow cracks.
The results were reported at the American Geophysical Union (AGU) Fall Meeting in San Francisco, California.