Re: pinhole Re: Leap second-->tidal forces

Date view Thread view Subject view Author view Attachment view

From: Paul Doherty (pauld@exploratorium.edu)
Date: Fri Nov 21 2003 - 13:37:13 PST 

Message-Id: <l03110752bbe434805174@[192.168.112.78]>
Date: Fri, 21 Nov 2003 13:37:13 -0800
From: Paul Doherty <pauld@exploratorium.edu>
Subject: Re: pinhole Re: Leap second-->tidal forces

Tidal forces between the earth and moon have already slowed the moon so
that one face is always pointed toward the earth.

Eventually tidal forces between the earth and moon will cause the system to
evolve so that one face of the earth always faces the moon.

The earth will not evolve due to solar tides so that one face of the earth
is always toward the sun. (The tidal drag force falls off as the inverse
sixth power of distance, the tidal height force falls off as the inverse
third power of distance) So the solar drag is much smaller than the lunar
drag.

By the way Pluto and its moon Charon, have already evolved to the state
where Charon keeps one face toward pluto and pluto keeps one face toward
Charon.

Paul D

>Tidal forces between Earth and Sun, or Earth and Moon? Speaking of
>which, is it true that, in time, tidal forces between the earth and sun
>will make it so that one side of the Earth always faces the sun in the
>same manner that one side of the moon always faces the Earth?
>
>
>On Friday, November 21, 2003, at 11:29 AM, SFPhysics@aol.com wrote:
>
>> However, due to tidal forces slowing the earth's rotation there is one
>> on
>> going time adjustment besides the leap year. It is the leap second.
>> The actual
>
>
>---------------------------------------------------------------------------
>
>To unsubscribe from pinhole, send an email to requests@exploratorium.edu
>with the words 'unsubscribe pinhole' (without the quotes) in the SUBJECT
>of the email.
>
>To subscribe to the digest and only get 1 combined message a day, send an
>email to requests@exploratorium.edu with the words 'subscribe digest
>pinhole' (without the quotes) in the SUBJECT of the email.
>
>Check out what your colleagues have written on Pinhole in the Pinhole
>archives at: http://saturn.exploratorium.edu/ti/alumni/pinhole.html
>---------------------------------------------------------------------------

Date view Thread view Subject view Author view Attachment view

This archive was generated by hypermail 2.1.3 : Mon Aug 02 2004 - 12:05:33 PDT