Re: [asa] geocentricity

Merv -

My choice of coordinates doesn't force anybody else to do anything. You can also use any coordinates you choose. & if we each make measurements correctly we'll find that our results for distances, times, velocities & various other things will differ, but we'll be able to agree on the laws that the phenomena obey if those laws have been formulated in accord with the relativistic transformation rules.

Using a particular coordinate system doesn't mean that one has to be in any particular place or move in a particular way. It's simply a choice of a way to describe the world for a particular problem. & you can use more than one such system if you're careful to keep track of which is which. If I may quote a note of Schrödinger's (Expanding Universes, p.20):

"Let me on this occassion denounce the abuse which has crept in from popular exposés, viz. to connect any particular frame of reference, e.g., in special relativity, with the behavior (motion) of him who uses it. The physicist's whereabouts are his private affair. It is the very gist of relativity that anybody may use any frame. Indeed, we study, for example, particle collisions alternately in the laboratory frame and in the centre-of-mass frame without having to board a supersonic aeroplane in the latter case."

Shalom
George
http://web.raex.com/~gmurphy/
----- Original Message -----
From: <mrb22667@kansas.net>
To: "George Murphy" <gmurphy@raex.com>
Cc: <asa@calvin.edu>
Sent: Friday, July 06, 2007 12:23 PM
Subject: Re: [asa] geocentricity

Quoting George Murphy <gmurphy@raex.com>:
>
> The choice of space-time coordinates is entirely a matter of convention &
> convenience, with no fundamental significance.
>

Certainly this pushes Occam's razor to an extreme, though, George? Aren't you
forced to admit that this "convenience" is a rather severe difference in more,
somehow, than just a matter of degree? To press the point, I can choose myself
as the reference frame, in which case I can, from the middle of my living room
force the entire universe to accelerate into a spin, and then decelerate --
complete with all the complicated math involved. To call the earth just as
eligible as anything else for a cosmologically stationary reference frame is
basically no different than you in the living room being that frame and
insisting that everyone in the world disregard the inconvenience. There is a
difference.

--Merv

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 Fri Jul 6 13:27:00 2007