[QUOTE=deanc2000]
The moon is also responsible for the tilt in the earth’s axis. If the moon were to disappear, then the axis, which if I remember correctly is tilted around 10-15 degrees, would fluctuate more wildly. It would perhaps go to 60-90 degrees.
This would have the affect of changing climate everywhere on earth, as now the north pole is where the desert used to be (at some point).
So whoever said it had minimum affect on climate is completely WRONG.
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sigh I’m not sure you could pack more wrong into such a short space if you tried. First of all, the tilt of the Earth’s axis with respect to the solar ecliptic plane is approximately 23.4 degrees, with about a 2 degree overall variation in a 23,000 year cycle. The orbit of the Moon about Earth is at an angle of 5.2 degrees to the solar ecliptic. The Moon may provide some moderating influence to the variation, but it is highly unlikely that the polar orientation of the Earth would “fluctuate more wildly…60-90 degrees”. However, as rotational momentum is leeched from the Earth via tidal interactions with the Moon, it will actually become more susceptible to external influences. Far from being a stabilizing influence, the Moon is actually contributing to the loss of Earth’s natural gyroscopic stability. Mars, which essentially lacks any moons (Deimos and Phobos are captured asteroids that have no calculable effect on the rotational behavior of their parent), has an axial tilt of 25.2 degrees to the ecliptic and an estimated tilt range of 15 to 35 degrees. Mars is also significantly less dense than the Earth and smaller, and thus presumably more affected by external couples that would cause variations in axis tilt.
Second, I’m not really clear what you mean in your statement, “…the north pole is where the desert used to be (at some point).” I’m not sure to which desert you are referring, but there is no credible evidence that the axis of the Earth has ever varied dramatically (though what evidence we have is limited by the age of the crust). It’s certainly possible that a land mass crossed the North Pole during tectonic movements from the breakup of Pangaea through the modern day, but that has nothing to do with the rotation of the Earth.
Third, even a modest axial tilt would have an effect on the climate by altering the duration and intensity of the seasons, and additional nutational modes resulting from the sudden disappearance of the Moon would certainly contribute to this, but again such variations would be minor (fractions of a degree) over periods of centuries or larger. If the Earth were to somehow undergo some massive rotational shift–say even one of five or ten degrees–the resultant effect on Earth’s climate and the ecosystems adapted to that regular variation would be extreme, probably killing off all megafauna and much flora, leaving simpler and more adaptive organisms to rebuild. More dramatic variation might destory virtually all life entirely by permanently disrupting the critical vapor cycle, making the planet uninhabitable by anything more complicated than single cell organisms.
While the force of the Moon’s influence on any small collection of water may be tiny, the whole amount of energy is huge. If that force is released all at once, that energy goes somewhere, and because it can’t really go down (water and the seafloor below it being pretty much incompressible) it’ll spread out in an expanding wave, which will become higher as the depth gets shallower. Once expended, however, there is nothing else to drive tidal forces; after the inital tidal blast, there won’t be any more lunar tides, ever. There’ll still be solar tides, of course, but these will be less dramatic.
[QUOTE=Alistair McCello]
By my armchair understanding of quantum mechanics (those who actually know this stuff well, please correct me if I am wrong) it actually would be possible for the whole moon to vanish, but the probability for such an event is so low that the post size limit here would prevent me from get anywhere near typing out the number.
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Any system of fundamental particles can be considered a superposition of the probabilities of the individual particles. However, by the time you get up to the level of molecules the molecular structures themselves are considerably larger than the amplitude of the waveform (so that the molecule always appears to be almost exactly where you expect it) and quantum effects at that level are very small, limited to the tiny variations that cause statistical mechanics to be, well, statistical. At the level of stuff you can even examine optically–say, a speck of dust–the waveform is so much smaller than the object that you can treat it classically in terms of mechanical interactions. For an object the size of the Moon its variation from its nominal position is far less than it is possible to measure, even in theory, even on quantum scales. For all intents and purposes, the Moon is exactly where it appears to be. While it is nominally possible to calculate a possibility that the Moon is across the Solar System, the likelyhood of this occuring in the lifetime of the Universe is virtually infinitesimal. In any case, as Chronos notes, the energy bound up in the Moon (i.e. its mass and momentum) can’t just disappear, and even if it flitted across the Galaxy for an instant, it would be back the next. (The average speed can’t exceed the speed of light without creating a lot of problems even before you get to relativity, but that’s another problem entirely.)
I don’t know how you’d cope with the gravitational implications of this, since there’s no accepted way to cope with the gravitational force in quantum mechanics. Presumably the field would remain centered on the nominal position of the Moon, but that doesn’t seem to make sense, either. The idea underlies the whole problem between General Relativity and quantum mechanics, which makes a lot of people very nervous so they prefer to think about reality television shows and midget pornography instead, hence the popularity of the Internet. Bizarre how it all comes around, init?
Stranger