[time-nuts] Information on the Danjon Astrolab
cfmd at bredband.net
Tue Aug 8 17:34:56 EDT 2006
From: Rasputin Novgorod <priapulus at yahoo.com>
Subject: Re: [time-nuts] Information on the Danjon Astrolab
Date: Tue, 8 Aug 2006 13:49:29 -0700 (PDT)
Message-ID: <20060808204929.10631.qmail at web50715.mail.yahoo.com>
> > ofcourse they have a different local gravity and the
> > gradient of that
> > will differ (and hence the angle of the gravity will differ slightly
> > from that
> > of the normal on the ellipsoid). Ever looked at a gravity map of the
> > earth?
> Wait a minute. The center of gravity ~is~ the center of gravity.
> You can't have two, or multiple centers. The strength of gravity
> varies from place to place, but that doesn't change the direction.
> If I'm wrong; please explain...
First of all, this ball of iron and siliconoxide that we call home, is far from
homogene. This causes local variations in gravity, simply because the local
ore may be heavier than the average crust. This does not only cause the gravity
to be stronger downwards, but also affect things sideways. As you get closer to
such an area your gravity force will point more towards that area rather than
towards the gravity center of earth. Thus, the gradient of the gravity force
will help to point you off center so to speak. Another fun little gravity play
is that ball of stone that made a wonderfull spectacle in the sky this evening,
called the moon. It's gravity will also pull things, such as water, and do that
Did that make sense?
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