-----Original Message-----
From: Schmidt Mickey Civ 50 TS/CC <[EMAIL PROTECTED]>
To: [EMAIL PROTECTED] <[EMAIL PROTECTED]>
Date: Tuesday, February 27, 2001 10:13 AM
Subject: RE: Europa submersible hypothetical
>
>These may seem a very naive questions and if they are I apologize, but I am
>interested in answers to several questions.
>1. Can it be said that Europa's ice crust is floating on a liquid layer? I
>assume Yes is the answer.
Yep.
>2. If it is floating and if the ice is several kilometers thick what is the
>magnitude of the pressure on a submersible say 100 meters below the ice?
>Is the amount of pressure the sum of the weight of ice directly above
>plus the weight (in Europan gravity)of the 100 meters of water.
Yep. (Europan gravity is about 1/7 that of Earth.) So even if the floor of
the ocean is beneath a total of 150 km of ice and liquid water (as may be
the case), the pressure there would be only about twice that at the bottom
of the Marianas Trench.
>6. Is there a "radiation wake" anywhere on Europa where, due to its motion,
>or being tidally locked to jupiter, the effect of the Jovian Radiation
belts
>is lessened?
Yep -- and, paradoxically, it's the side of Europa facing forward in its
orbit. Because Jupiter's rotation -- and therfore the rotation of its
magnetic field, and the rotation of the charged-particle radiation and
plasma that the field drags along -- are all faster than the rate at which
the Galilean satellites revolve around Jupiter, the wake that they plow in
the magnetosphere runs ahead of them along their orbital path (whereas the
solar-wind wake of all the planets points away from the Sun). The same is
true of most of the moons of the other three giant planets. And the surface
compositions of some of the giant planets' moons do seem to reflect this
uneven radiation exposure -- for instance, there is more sulfur dioxide
(presumably from Ionian ions) on the trailing faces of Europa, Ganymede and
Callisto.
>7. I have seen many chemicals suggested as being in solution, or lately, in
>combination would have preciptiated out. Has anyone collected a list of
>these "potential" chemicals? Seems like that would be the makings of a
>decent science project to see what's left if they are/were all there an one
>time.
I actually saw such a list on a slide during one of the talks at the Europa
Focus Group meeting -- and it was one hell of a long list. It included (and
these are the ones I can remember) hydrogen peroxide, oxygen, sulfuric acid,
carbonic acid, carbon dioxide, ammonia, formaldehyde (and other more complex
organic compounds), magnesium sulfate, sodium sulfate, sodium carbonate,
sodium chloride, and no doubt some others. Some of them do seem to be
mututally exclusive -- as I said in a recent post, magnesium sulfate and
sodium carbonate would react with each other and turn into sodium sulfate
and (insoluble) magnesium carbonate, and ammonia would react with some of
the others. (I'll poke around soon in the past few years of LPSC abstracts
on the subject and see if I can dig up something more specific.)
Bruce Moomaw
==
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