Water plumes over Europa |
Water plumes over Europa |
Dec 12 2013, 04:55 PM
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#1
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Member Group: Members Posts: 401 Joined: 5-January 07 From: Manchester England Member No.: 1563 |
This seems like the relevant place to post this (could be wrong): Water plumes from Europa? Apologies if it's already been up. The link to the Science article at the bottom doesn't work for me, does anyone have a working link to the original? Cheers.
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Jan 1 2014, 05:12 PM
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#2
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Senior Member Group: Members Posts: 3419 Joined: 9-February 04 From: Minneapolis, MN, USA Member No.: 15 |
So, observed species abundances reflect the end result of a process of emission of some carbon species, the dissociation of those species in the radiation environment, and finally the recombination of some species (as allowed by the environment) and the emplacement of these recombined species on the surface?
Just trying to wrap my mind around the most likely process. Seems to me that modern science offers a lot of theoretical concepts that are weak on the actual processes you have to have to get to the current observed conditions, which is why I'm always harping on the process side of things. -the other Doug -------------------- “The trouble ain't that there is too many fools, but that the lightning ain't distributed right.” -Mark Twain
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Jan 3 2014, 06:57 PM
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#3
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Senior Member Group: Members Posts: 2530 Joined: 20-April 05 Member No.: 321 |
Other Doug,
I think it's useful to consider the relative rates of processes on the surface of a world. We have few visible craters on Earth because erosion and tectonics both work faster than impact cratering. On Europa, the effects of radiation work fastest, although those obviously alter only the immediate surface. Recycling of crustal material (faults, occasional melt-through) is next fastest. Then the flux of major impactors comes after that. I've read enough about Europa to know that there are certainly unknowns and seemingly unknowable unknowns (to paraphrase Donald Rumsfeld), or at least internal parameters that cannot be deduced unless we get hard data about the interior of a kind we don't have, or someone comes up with new and clever ways of interpreting the clues we have. It is generally the case that the interior properties of worlds are hard to pin down without a tremendous amount of in situ seismographic, etc, data of a kind we have only for Earth and to a lesser extent the Moon and a far lesser extent Mars. |
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Jan 8 2014, 10:21 PM
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#4
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Senior Member Group: Members Posts: 2530 Joined: 20-April 05 Member No.: 321 |
The options for future Europa missions have to highlight a sample return that flies through the plumes, collects material, and returns to Earth. One of the big problems with this architecture is the inconsistent nature of the plumes. A free trajectory return from Earth back to Earth by way of Jupiter has the least possible delta-v, but is also completely inflexible to midcourse adjustment, and it could miss the active period of the plumes.
So an intriguing alternative has to be a mission which enters Jupiter orbit and parks, waiting for the plumes to become active, possibly performing the observations that determine when the plumes are active. To be practical, this would mean something like a Galileo-style elliptical orbit with apojove well outside the orbit of Callisto, and perijove well outside the orbit of Europa. When the determination had been made that the plumes were active and likely to remain so, it could perform a single pass over Europa's surface, perform the collection, and then exit Jupiter orbit for a return to Earth. This would entail more delta-v than the free return trajectory, but avoids the reliance on a single timeframe for sample collection, and still entails vastly less delta-v than a lander-based sample return. It would also offer opportunities for flyby science of Callisto and Ganymede and long-range science of Jupiter, Io, and Europa. I think something like this has to become a major candidate for a future mission. |
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