To: WSFAlist at keithlynch.net
Date: Sat, 23 Mar 2002 02:15:02 -0500
Subject: [WSFA] the earth's tilt
From: ronkean at juno.com
Reply-To: WSFA members <WSFAlist at keithlynch.net>

On Fri, 22 Mar 2002 19:06:35 -0500 Candy Madigan
<candymadigan at mindspring.com> writes:
> I was JUST involved in a conversation about whether the earths tilt
> was
> changing and that was an explanation for the 'strange weather' that
> we've
> been getting.  I rejected that hypothesis based on the fact that the
>
> soltices/equinoxes are still coming when predicted.
>

The earth's tilt (the obliquity of the ecliptic) does change over time.
It wanders back and forth between two extremes which are only a couple of
degrees apart.  The obliquity of the ecliptic is the angle made by the
plane of the earth's equator with plane in which the earth orbits.  The
effect, I think, is mainly that seasonal weather differences would be
greater when the tilt is greater, and less when the tilt is less.  But
the tilt changes so slowly that for centuries it has remained mighty
close to today's 23 1/2 degrees.  The tilt controls what the latitudes of
the Tropics of Cancer and Capricorn will be, and the latitudes of the
Arctic and Antarctic Cirles.  At this time, the tropics are 23 1/2
degrees from the equator, and the Arctic and Antarctic Circles are 23 1/2
degrees from each of the respective rotation poles.

Ron Kean

.

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