[time-nuts] Chilean quake shifted Earth's axis. The length of the day shorter by 1.26 microseconds ?
Mark Sims
holrum at hotmail.com
Tue Mar 2 04:36:19 UTC 2010
Pretty trivial to do with GPS where a 1 ns error is under 1 foot of position error (and a geodetic grade GPS can give sub-millimeter accuracy)... even a cheap consumer grade unit is under 10 feet of error. 1.26 us of orbital change is over 1100 feet of error.
One trick is to compare the pre-earthquake GPS almanac/ephemeris data with the post earthquake data. I suspect that a lot of geodetic monitoring stations are scrambling to keep up with what the earth is currently doing.
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How would one go about verifying this? The angular difference after 1
year is about 3E-8 radians, which is probably well beyond the absolute
pointing accuracy of any telescope, and swamped by lunar tidal
deceleration anyway.
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