Starship Asterisk*

Jupiter's Europa from Spacecraft Galileo

Explanation: What mysteries might be solved by peering into this crystal ball? In this case, the ball is actually a moon of Jupiter, the crystals are ice, and the moon is not only dirty but cracked beyond repair. Nevertheless, speculation is rampant that oceans exist under Europa's fractured ice-plains that could support life. This speculation was bolstered again this week by released images from the Hubble Space Telescope indicating that plumes of water vapor sometimes emanate from the ice-crusted moon -- plumes that might bring microscopic sea life to the surface. Europa, roughly the size of Earth's Moon, is pictured here in natural color as photographed in 1996 by the now-defunct Jupiter-orbiting Galileo spacecraft. Future observations by Hubble and planned missions such as the James Webb Space Telescope later this decade and a Europa flyby mission in the 2020s may further humanity's understanding not only of Europa and the early Solar System but also of the possibility that life exists elsewhere in the universe.

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The Hubble site says they estimate the plumes to travel to 125 miles up before then falling back to the surface. Using 1.315 m/s2 as Europas gravity, that would require a minimum of about 40,000 PSI pressure under the surface to force water to that height. And it would be leaving the surface at about 1,600 miles/hour.
This is a rough calculation ignoring a few things, but it gives an idea of a minimum to reach those heights.
Hopefully those high pressures are local, and not all encompassing in Europas sub-surface ocean.

Wadsworth wrote:
The Hubble site says they estimate the plumes to travel to 125 miles up before then falling back to the surface. Using 1.315 m/s² as Europas gravity, that would require a minimum of about 40,000 PSI pressure under the surface to force water to that height. And it would be leaving the surface at about 1,600 miles/hour.

This is a rough calculation ignoring a few things, but it gives an idea of a minimum to reach those heights.
Hopefully those high pressures are local, and not all encompassing in Europas sub-surface ocean.

Io's gravity is 37% greater and its material (sulfur) is 2 times denser and yet Io's volcano Tvashtar can spew material 200 miles into the air at ~45º.

Yes... and Io is spewing sulfur, whereas Europa is - perhaps - spewing water ice.

Ann

It resonates differently in my mind when thinking about it as a 'volcano' instead of pressure being released from a sub-surface ocean.
I'll have to ponder on this a bit more.

The images/gif of Io's volcano are much more impressive than the recent -possible- plumes of Europa caught by Hubble. I wonder if Juno will get any images of Europa..

Nice pic...
On Life... you need more than just water... and just an ocean. You need the ELEMENTS of life... Cellulose... "Cellulose is the Earth's most widespread natural organic chemical." 700 billion TONS...
Show me the Cellulose...to make CELLS... and thus life...

http://www.universetoday.com/13399/want ... cellulose/

Interesting article...

Plus Headline...."There's Salt Water On The Surface Of Europa, Which Could Be Good News For Extraterrestrial Life"

So... several things to look at...

:---[===] *

Ann wrote:
Yes... and Io is spewing sulfur, whereas Europa is - perhaps - spewing water ice.

Good article in latest Scientific American about the water plumes of Enceladus (escape velocity = 0.24 km/s) which don't immediately rain right back but rather form Saturn's E-ring. The driving force on Enceladus is CO₂ gas (as it probably is for Europa). I would assume that the driving force for IO sulfur plumes is SO₂ gas.