mrudis65 said:
I am writing an interactive fiction roleplaying game. It is futuristic... in fact centuries away.
Why not?
We have discovered that the core of Europa is indeed liquified iron, silicon (and sulphur gas?)
Io is believed to have a core of liquid Iron sulfide. Not sulfur gas.
The oceanic layer is indeed liquid water. Not only that, but it was discovered that a very thin layer of oxygen, nitrogen, hydrogen and other trace elements exists between the ocean and the outer frozen shell.
The Shell has to be in contact with the ocean - the pressure is too high for gas pockets. However, the ocean is very likely to have dissolved oxygen and peroxide from the radiolytic chemistry driven by Jupiter's magnetosphere's trapped particles striking the surface ice.
To be determined is: whether there are fissures that release geo-thermal energy (heat) into the ocean. What would be the complications and implications of this?
Depends. Europa's ocean/ice-shell is believed to be ~100 km thick. At the bottom the pressure is about ~1400 bar and in direct contact with the silicate interior. There has to be a lot of geothermal activity for an ocean to remain liquid. The important question is whether that means enough energy to power a vigorous biosphere. Lots of black-smoker like mineral outflows, perhaps, but beyond that...?
First, where can I find the most recent data on the composition, known elements, temperature, etc... for Europa?
Wikipedia is a good start, surprisingly. Then look at all the astrophysical journals. Best way to do that is via NASA's Astrophysical Database Server...
http://adsabs.harvard.edu/abstract_service.html"
And second, in order to make my story compelling to scientists and physicists (I'm a mathematician) I would like input as to what a potential human colony might look like, given the scenario described. The storyline is not intended to be beyond the grasp of a non-scientist. However, I would like the descriptions of structures and habitats to be in the realm of theoretical possibility, however remote. Would there be volcanic activity? If so, how does one explain the smooth and non-punctured surface?
Read some articles about Europa and you'll get a better picture. There's lots of material available. The crucial question is just how thick the ice is and Europa's present day outwards heatflow would have a lot to do with that. The estimates vary. Read widely and you'll see a broad range of opinions. But to give you a rough idea the super-volcanic moon Io is believed to have a geothermal heat-flow of about 3 W/square metre. Earth's is ~0.08 W/sq.m. Europa is somewhere in between. Call it 1 W/sq.metre. The surface temperature is about ~100 K. An ocean is at about ~277 K. That's a temperature gradient of ~177 K. Ice has a thermal conductivity of about 4 W/m.K, thus to reduce support a temperature gradient of ~177 K that 1 W/sq.m heat-flow needs an insulating blanket of 4 x 177 metres of ice, minimum. Europa's surface gravity is ~1.35 m/s^2, thus the minimum ice-blanket exerts about ~900 kPa on the ocean. "Warm" ice can undergo solid-state convection and that supports a shallower thermal gradient, meaning a much thicker ice-layer is needed. How much thicker? No one knows. Make an informed guess.
But that's
average thickness. Tidal flexing over Europa's orbit can cause channels in the ice to open and close, thus a literal rising and falling of the ocean with the tides, perhaps by hundreds of metres. Some kind of photosynthesis might even be possible when the tide rises to its highest. Contrary to the gloomy statements by the other posters, the thickness of ice Life needs for radiation protection is trivial - less than a metre will do. And x-rays produced by high-energy collisions might provide another source of energy for an alien photosynthesis - even on Earth there's a fungus suspected to use x-rays produced by nuclear reactors for biochemical energy.
So go from there. I hope I've helped stimulate your imagination some more.
