Been waay to overextended rounding on service with the fellows to comment but
compelled to do so. I am not sure why but GR and SR are thought of as exotic
and not relevant to everyday existence.
I was going to comment days ago on GPS too. The satellites have to be synced
to ground and stay within a few tens of nanoseconds to work well. Without both
SR and GR effects adjusted for the system is trashed
in a short time and errors accumulated in estimated distances by about 10km per
day. GR predicts due to curvature of space-time the satellites atomic clocks
will tick about 45 microsec faster. Note that is a dramatic error for the
required accuracy.
Due to the relative speed of the satellites compared to ground based clocks SR
predicts the satellite clocks will be 7 microsec slower. So the net delta is
38microsec--this is programmed into the system.
So relativity is as close as our phones or other gps devices---no geotagging
photos with any accuracy without Uncle Albert.
http://www.astronomy.ohio-state.edu/~pogge/Ast162/Unit5/gps.html
Curiously the notion that the expanding universe is accelerating requires
further confirmation. The study performed in the late 90's led to a Noble
prize using Type1a supernovae as standard candles. This was recently redone
with 10 times the data set using 740
supernovae and was significant to only 3 sigma standard not the usual 5 sigma
required--physics is the hardest of the hard sciences and requires demanding
standards for good reason. There is other indirect evidence of this
acceleration but it is much less
robust--this can be totally confirmed or refuted with other techniques (laser
frequency comb) and of course it is a source of intense scrutiny. This has
major implications for cosmology.
In most areas of science worth their salt if the emperor's tie is askew, much
less has no cloths, someone is going to put a microscope on the issue and go
shouting down the halls. It may take longer to get published, but it will
happen.
It's all relative, Mike
--
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