unruh wrote:
On 2010-02-12, John Ackermann N8UR <j...@febo.com> wrote:
Another great experiment -- done by an amateur
time-nut, Tom Van Baak -- took three 5071As on a camping trip up a
mountain in Washington state and verified Einstein's prediction of a
change in clock rate with elevation. Take a look at
http://www.leapsecond.com/great2005/index.htm and be amazed.
That's about 2Km, which is a time difference of 2 parts in 10^-13. Ie,
if he was up there a day, the time difference would be 10ns. I wonder if
they are really that accurate.
The ultimate was the Vessot experiment in which a H maser clock was shot
up to 10000Km and the special relativisitic and general relativistic
time shifts were measured.
Bender claims that the GPS engineers did not believe that GR was real,
and had a software switch which they could use to eliminate the General
Rel corrections in the GPS.
I think Tom spent closer to two days on the mountain, and he was using
5071As with the high stability cesium tube option (and the three he took
up were selected as best performers from his collection). The 5071As
have stability down to parts in 10e14. I'm not certain, but I think
that his stationary reference was an H-Maser. His measurement
resolution was in the picoseconds.
John
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