Re: [asa] geocentricity

& just to ad to this: My statement that one can do physics in a geocentric
frame is technically correct but has an ex post facto nature. I.e., you
solve Einstein's equations for the solar gravitational field - i.e., the
space-time geometry in the sun's vicinity - & find the motion of a particle
in that field & then transform to a frame in which such a particle is at
rest. I'm not sure offhand how I'd even go about working out the details of
the problem from the start in a geocentric frame (at least if an exact
solution were wanted) though I know it's possible in principle.

Shalom
George
http://web.raex.com/~gmurphy/

----- Original Message -----
From: "gordon brown" <gbrown@Colorado.EDU>
To: <asa@calvin.edu>
Sent: Thursday, July 05, 2007 2:10 PM
Subject: Re: [asa] geocentricity

> Since motion is relative, one could declare the earth to be fixed, center
> one's coordinate system there, and, in theory, rewrite the laws of physics
> using those coordinates. Then attribute to the rotation of the heavens
> what is due to that of the earth. If you didn't want to do physics or
> astronomy, you would see no reason to change, but if everyone had taken
> this approach, many areas of physics would not have advanced since the
> fifteenth century because it would look too complicated. Since not much
> physics can be developed from it, we can't give many examples of what
> geocentricity accurately predicts.
>
> Gordon Brown (ASA member)
>
>
>
> To unsubscribe, send a message to majordomo@calvin.edu with
> "unsubscribe asa" (no quotes) as the body of the message.
>

To unsubscribe, send a message to majordomo@calvin.edu with
"unsubscribe asa" (no quotes) as the body of the message.
Received on Thu Jul 5 17:17:45 2007