Plumes of material erupt from the long 'tiger stripe' fractures on the south pole of one of Saturn's moons, Enceladus.
Credit: NASA
Schneider's team directly observed the plume using ground-based spectrometry from one of the twin 10-metre Keck telescopes in Hawaii and the four-metre Anglo-Australian telescope in Coonabarabran, NSW.
Astronomers previously thought the plume spurted out from cracks in Enceladus' icy surface, fed by a hot spot below, in the same way that geothermal activity on Earth creates geysers of superheated water.
Instead of a geyser, the lack of sodium in the plume's vapour suggests a "wide variety of alternative eruption sources, including a deep ocean, a freshwater reservoir or ice," Postberg and his colleagues wrote.
"The original picture of the plumes as violently erupting Yellowstone-like geysers is changing. They seem more like steady jets of vapour and ice fed by a large water reservoir.
"There could be something living there"
"However, we can't decide yet if the water is currently 'trapped' within huge pockets in Enceladus' thick ice crust or still connected to a large ocean in contact with the rocky core," said Postberg.
Astrobiologist Malcolm Walter, director of the Australian Centre for Astrobiology at the University of New South Wales, Sydney, said the find was "very significant" as it indicated at some stage there was a salty ocean on Enceladus.
"It doesn't prove it, but it is consistent [with a salty ocean] because the salt had to come from somewhere, probably the rocky core of Enceladus," he said.
The ground-based observations may not have detected sodium, but there could still be salt in the plume, because the ground-based spectrographs were searching for atomic sodium, not sodium locked up in salt, he said, "whereas the Cassini spacecraft can directly detect the salt."
"If there is a salt ocean, then there could be something living there."
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Do any moon's spin ?
Our's doesn't, we all know that, and I can't see why any should, but it intrigues me and I'd love an answer if there is one?
The Moon does spin
If I remember correctly, the Moon does spin on an axis. It takes 28 Earth days to finish one Lunar day though. So because the time it takes for the Moon to orbit and and turn, thats why we only ever see one side.
planets and moons
I may be a ?? year old kid! but i know alot about space, you see, the earths axis is 24.3 degress clockwise so really were diagonal!!!!, the moon does spin, so fast that we only see one side of the moon (the 'sea of tranquility')
but its actually 27.3 earth days it takes for a full lunar thing so ha!, venus is 425 degress celcious hot hot!
mercury is so far the fastest planet in our solar system,
earth supports life (obviously!) mars is actually rusty because of the carbonate and sulphur in its core getting burned, saturn is a gas planet, i found out by a scientist that at the bottom of one of saturns moons is water! which supports life!! (fish life! this is true), jupiter is bigger than saturn and the 'red spot' is actually a 1,030km storm that can fit 3 earths inside! uranus is pure gas, sadly thats all i know so far about uranus, neptune isnt actually water, its clouds full of carbon dioxide and methane and more! but its core has loads of water in it (and ice and iron) and NOT last of all, pluto! pluto is so small it has an irregular orbit so it takes over the orbit of neptune so neptune is the last haha, but it takes 5 years for pluto to get in front of neptune and 6 or 7 years to get behind it again!!!!!!!!!
thats all
~anonimous