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Re: Does the earth wobble?

>Of course the earth wobbles, but only by a degree or so either
>way.  The wobbling is on such a short cycle that it is irrelevant
>to dino extinction.

First, may I wish all you Americans (and, of course, all free people)
Independence Day Greetings.

Now, I have a question. How is "wobble" measured? I expect that it is so
slight that it is very hard to detect.

The figure of 20,000 years for the cycle has been bandied about. Is it
possible that this is simply a "harmonic" of a much longer cycle, perhaps
lasting millions of years and going through a larger angle? Obviously a
longer cycle would be harder to detect.

I don't think wobble is likely to be a cause of extinction. My point is that
if the tilt of the Earth was different during the mesozoic it would have a
huge effect on the climate, particularly near the poles. If the earth had no
tilt there would be no seasons, or if the angle was smaller the effect of
seasons would be much less. We know the earth was much warmer then, and this
could offer a partial explanation why.

On the other hand, if I am flogging a dead horse, please let me know.

James Shields