-----Original Message-----
From: Daniel R. Zeigler, Ph.D. <[EMAIL PROTECTED]>
To: [EMAIL PROTECTED] <[EMAIL PROTECTED]>
Date: Monday, February 26, 2001 7:30 AM
Subject: RE: Europa submersible hypothetical
>
>Jayme-
>
>At the Europa Focus Group meeting earlier this month, it was obvious that
>there is no clear consensus on the composition of the ocean. For sure, if
>the ocean exists, it's cold-right around zero degrees Celsius, except
around
>any thermal vents (which may or may not exist). People seem fairly sure,
>from the induced magnetic field, that the ocean is very salty. Models
>indicate that the salts are probably mostly magnesium and sulfate, although
>some sodium and carbonate are probably present, too. We have quite a bit
>less confidence about the pH. A sulfuric acid ocean seems favored at this
>point, although folks at the EFG were still talking about neutral and
>alkaline models.
>
>Jeff Kargel's models are pretty impressive, in my opinion. If we were to
>select one that seems to fit the available data and the theories of Europa
>formation the best, the ocean would be a cold solution of magnesium sulfate
>and other salts (a little more concentrated than the Dead Sea) at a pH of
>around 1. MgSO4 solutions are colorless and odorless. Concentrated
>sulfuric acid is also colorless and odorless and fairly viscous, even oily
>if you were crazy enough to stick your hand in it. It doesn't have an odor
>like acetic acid, for example. Conc. sulfuric does give off vapor, though,
>and if you snort some accidentally it will irritate or burn the lining of
>your nose. (It's not fun.) Probably at Europan concentrations there
>wouldn't be a lot of vapor. Highly corrosive solution, though. Your sub
>might have to be gold-plated, a "yellow submarine!"
Yep, I was there too. Accurate description -- except that it's uncertain
whether the high conductivity of the subsurface Europan ocean apparently
discovered by Galileo is due to high salinity or to high sulfuric acid
content. (Also --as I said earlier -- there may very well be a significant
amount of dissolved elemental sulfur as well, which would provide a definite
odor.) But -- as Dan says -- the main conclusion the conference reached was
that we really know hardly anything that we need to know about Europa's
composition, and that surface composition measurements are an extremely
important part of any future Europa exploration program (and one which has
been short-changed in the curent Europa Orbiter design).
Bruce Moomaw
==
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