Posted on 12/23/2008 8:46:26 PM PST by tricky_k_1972
The scarred surface of Europa may be due to the push and pull of Jupiter's gravity (Image: NASA/JPL/University of Arizona/University of Colorado)
Robert H. Tyler
Applied Physics Laboratory and Department of Earth and Space Sciences, University of Washington, 1013 NE 40th Street, Seattle, Washington 98105, USA
Correspondence to: Robert H. Tyler1
Correspondence and requests for materials should be addressed to R.H.T. (Email: tyler@apl.washington.edu).
Data from recent space missions have added strong support for the idea that there are liquid oceans on several moons of the outer planets, with Jupiter's moon Europa having received the most attention But given the extremely cold surface temperatures and meagre radiogenic heat sources of these moons, it is still unclear how these oceans remain liquid. The prevailing conjecture is that these oceans are heated by tidal forces that flex the solid moon (rock plus ice) during its eccentric orbit, and that this heat entering the ocean does not rapidly escape because of the insulating layer of ice over the ocean surface. Here, however, I describe strong tidal dissipation (and heating) in the liquid oceans; I show that a subdominant and previously unconsidered tidal force due to obliquity (axial tilt of the moon with respect to its orbital plane) has the right form and frequency to resonantly excite large-amplitude Rossby waves in these oceans. In the specific case of Europa, the minimum kinetic energy of the flow associated with this resonance (7.3 
1018 J) is two thousand times larger than that of the flow excited by the dominant tidal forces, and dissipation of this energy seems large enough to be a primary ocean heat source.
New Scientist excerpt:
Swirling waters boost chance of life on Europa 10 December 2008 by David Shiga
However, new calculations show that additional variations, due to a suspected slight tilt of the moon's spin axis relative to its orbital plane, make it possible for Jupiter's gravity to warm Europa's ocean directly by stirring up currents within it. The heat produced this way could exceed the amount generated by the flexing of Europa's core, according to Robert Tyler of the University of Washington in Seattle (Nature, DOI: 10.1038/nature07571).
Heating on other planets moons? Damn those SUV’s are bad.
What can we tax to cool Europa?
Obviously it's Bush's fault.
>basically the temperatures of Europa may be warmer than expected
Oh no! Global Warming has spread across the solar system, we’ve got to stop this pandemic before it goes interstellar! [/sarc]
“Heating on other planets moons? Damn those SUV’s are bad.”
I tell “believers” that I don’t know what kind of SUV’s they drive on Pluto or some other planet because those planets are warming up, too. Then I mention Sun spots, cycles, etc. At least it makes the idiots think about it.
Universal warming.
Selfish White People’s Fault.
Snowmobile tracks on Europa!
/mark
The so-called habitable zone around the Sun and stars just grew. Will make the hunt for life a lot more interesting.
I knew something felt weird.
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