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polar ice (was nuclear space engine - would it work ??)
In article , James Dolan wrote:
...hmm, lunar mascons mentioned in the wikipedia article that i just looked up do seem to all be on the near-side... There are some on the farside, but they're much less conspicuous -- few and small. And oddly enough, the South Pole - Aitken basin, the biggest impact crater of them all (discounting the possible Nearside Basin) and mostly on the farside, has no mascon, for unknown reasons. any possibility that the asymmetry between the sides developed and then as tidal locking gradually occurred the near-side drifted to become the actual near-side so as to minimize potential energy? I believe that's the current consensus view -- that the nearside-farside orientation of the asymmetry is a result, not a cause, because the basic asymmetry pre-dated the tidal locking. Turns out that it is a bit difficult to establish the precise history of the Moon's rotation and orbit, for two reasons. First, resonances are by nature non-linear, so the final result is not very sensitive to the initial conditions, and it's hard to extrapolate the current situation back to learn about how it evolved. Second, one crucial variable in the evolution of such systems is the rate of tidal energy dissipation... and for Earth, that's dominated by ocean tides, and varies strongly with the shape and position of the continents, which has changed over time in ways that aren't well calibrated (except for the fairly recent past). -- spsystems.net is temporarily off the air; | Henry Spencer mail to henry at zoo.utoronto.ca instead. | |
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