🚀 go-pugleaf

On 27 Aug, 19:57, Tom Roberts <tjroberts...@sbcglobal.net> wrote in
sci.physics.relativity:
> q-bit wrote:
> > As everybody knows time in free space goes faster than time on Earth.
>
> Let me accept your loose way of speaking. But I will discuss clocks, not
> "time".
>
> In WEAK GRAVITATIONAL FIELDS (the only kind you are discussing), one can
> find coordinates in which the metric is given by:
>
>         ds^2 = (1+2\phi) dt^2 - dx^2 - dy^2 - dz^2
>
> where \phi is the Newtonian gravitational potential, and I'm using units
> with G=c=1. Clearly the time coordinate t is the time displayed by a
> standard clock located at spatial infinity (\phi=0). Remember that \phi
> is negative everywhere, going to zero in the limit of spatial infinity.
>
> So one can easily compute the relative tick rates of clocks, using the
> Newtonian gravitational potential (not the gravitational force).
>
> A clock at rest on the surface of the sun (:-)) would tick slower than a
> clock at rest on the surface of the earth, by a factor:
>
>         (1+phi(sun))/(1+phi(earth))
>
> (\phi is small compared to 1, so I kept only the lowest-order term in
> the expansion of sqrt(.), which cancels the 2 above). This is nowhere
> close to your guess of a factor of 28 (I don't know the actual value,
> but I estimate it is between 0.999 and 1.0).
>
> A clock on earth ticks slower than a clock "in free space" (i.e. at
> "spatial infinity") by a factor:
>
>         (1+phi(earth))/1
>
> which I estimate is somewhere between 0.99999 and 1.0 (possibly one more 9).

Bravo Roberts bravo Tom bravo Albert Einstein of our generation
(Hawking is no longer the Albert Einstein of our generation)! That is
Divine Albert's Divine Science par excellence - I suspect you will
never again contradict it in the following silly way:

http://groups.google.ca/group/sci.physics.relativity/browse_frm/thread/f707a1d5efc0f961?
Tom Roberts: "In the best theory of space and gravitation that we have
today, General Relativity, any clock always ticks at it usual rate
[#], unaffected by its location, motion, or the presence of any
gravitation. Note, however, that in general the COMPARISON of clocks
at different locations is affected by such factors. (this effect on
the COMPARISON of clocks sometimes gets misinterpreted to imply the
clocks themselves are affected.)"

Pentcho Valev