Re: Confirmation of Relativity

[Leigh Palmer <palmer@SFU.CA>]

At 10:19 PM -0700 5/3/00, David Bowman wrote:
> I need to take a break from some late night end-of-semester grading.
> So I think I'll make a comment about Leigh's comment:
>
> > ...  Time runs more slowly on Earth than it does on the Moon, and
> > more slowly on an artificial satellite than on Earth's surface.
>
> The first claim here is correct, but the second needs to be qualified.

It certainly does, and David fixed everything up well, as usual, and
then taught me more I did not know. I should have said "on the Space
Shuttle" or "On an artificial satellite in low Earth orbit".

The GPS satellites are in ~12 hour orbits. The GR effect dominates in
this case, as it does in the geosynchronous (24 hour) case. GPS clocks
run faster than Earth surface clocks.

Many thanks, David, for the new insights. I will use them immediately.

Leigh