Scientists have often speculated that Jupiter's moon Europa might contain hidden oceans - and thus the potential for life.
But lakes buried too deep beneath the surface would be sterile.
Now, computer simulations based on scans of 'chaos terrain' on the surface suggest that an 'ice cave' might be buried near enough the surface to support life, with a floating 'cap' leading to a cave of salty slush.
It would contain as much water as the American Great Lakes.
The salty lake is thought to be locked within Europa's icy outer shell a few kilometres from the surface.
Other large pockets of liquid water are also likely to exist on the moon, it is claimed.
 |
| The lake is covered by a floating, shifting 'ice cap', scientists believe - and it's close enough to the surface that it could harbour life |
Scientists are excited by the discovery, which offers one of the best hopes yet of finding life beyond the Earth.
Evidence for the ice-covered lake in Europa's Thera Macula region is seen in the shape of the terrain above it. The site appears to be marked by a fractured and collapsing lid of floating ice.
On Earth, similar features in the Antarctic are caused by briny seawater penetrating and weakening ice shelves. They are also present in Iceland, where glaciers are heated from below by volcanic activity.
Scientists have long suspected that a liquid or slushy ocean exists under Europa's surface, warmed by the tidal forces of Jupiter's powerful gravity.
Theoretically, a liquid water ocean could provide a suitable habitat for life -- but only if it was not too far from the surface.
Experts disagree about how thick the layer of covering ice is. The new research, based on images from the Galileo probe, suggests that water 'lenses' could lie as little as three kilometres below the bottom of the surface crust.
Lead scientist Dr Britney Schmidt, from the University of Texas, said: "One opinion in the scientific community has been, 'If the ice shell is thick, that's bad for biology -- that it might mean the surface isn't communicating with the underlying ocean'.
'Now we see evidence that even though the ice shell is thick, it can mix vigorously. That could make Europa and its ocean more habitable.' The research, published today in the journal Nature, involved computer simulations based on observations of Europa and Earth.
Scans by the Galileo telescope suggest that the 'lake' might be close enough to the surface to support life Dr Schmidt's team focused on two circular bumpy regions on Europa's surface - known as 'chaos terrains'.
Their existence will only be confirmed by a new space mission designed to probe Europa's ice shell.
Such a mission, likely to employ ground-penetrating radar, is now under consideration by American space agency Nasa.
Commenting on the study, Dr Robert Pappalardo, senior research scientist at Nasa's planetary science section, said: "It's the only convincing model that fits.'
© Daily Mail, London |
E-mail
