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Re: Earth's rotational speed

Check out http://www.ldeo.columbia.edu/users/jcm/Topic2/Topic2.html which
is the source for the following:

2.5 Length of Day Variations.

While it might seem fairly incredible the length of the day is changing all
the time -- not by an amount that anyone would notice, but by amoints that
are easy to detect instrumentally. The changes are only a few milliseconds
(a millisecond is one thousandth of a second) but they are very easy to
measure. The record below shows that there are very regular variations and
also very irregular variations. All of the changes must in some way be
caused by the re-distribution of mass over the surface and with in the
Earth. Seasonal changes (curve d) are caused by the change in ice volume and
relative amounts of water in the atmosphere from summer to winter. Longer
period changes and shorter period changes (curves c and e respectively) are
more difficult to explain. Some are caused by the phase of the El Nino --
the Earth rotates differently in an El Nino year than in a La Nina year
because these phenomena change the distribution of wet and dry parts of the
world. Even longer period changes must be caused by processes in the deep
Earth that move masses around such as subduction of large slabs of
lithosphere. The cause of many of the longer period signals is not well
understood.



----- Original Message -----
From: "E.C. Muehleisen" <docmule@HOTMAIL.COM>
To: <PHYS-L@lists.nau.edu>
Sent: Monday, December 31, 2001 3:15 PM
Subject: Earth's rotational speed


I have been aware that the earth's speed about the sun varies as we travel
on our elliptical path. However, I have read that the earth's rotational
speed varies though the year. Would someone be so kind as to explain this
change in omega and also explain the implications on L and the
conservation
of angular momentum.
Perhaps this will prompt a return to things of physics rather than
government.
Then a last barb on the much ballyhooed tax "rebate." A quote:"Sometimes I
wonder if the world is being run by smart people putting us on or by
imbeciles who really mean it."

Too much of a good thing is wonderful!




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