[time-nuts] Valentines Day & Love Numbers

Tom Van Baak (lab) tvb at leapsecond.com
Wed Feb 19 23:21:44 EST 2014


See old posting: http://www.febo.com/pipermail/time-nuts/2011-January/053478.html

The effect is too small (~5e-17 over 6 hours) to affect GPS time transfer. 


> On Feb 19, 2014, at 8:24 AM, Brooke Clarke <brooke at pacific.net> wrote:
> Hi:
> In the video about the Full Moon Curse (that's about measuring the distance to each of the 5 retro-reflectors on the moon to 1 mm) there's a plot showing the elevation change in the Apache Point Observatory of about 20 inches peak to peak.  It's exactly the type of change the effects pendulum clocks.
> I asked Tom Murphy if he used GPS to get the elevation plot and the answer is that it came from the gravitymeter with the use of Love numbers.
> http://en.wikipedia.org/wiki/Love_number  <- has links to papers on Earth tides
> Also see patent 3449956 and GWR instrument link at:
> http://www.prc68.com/I/Pendulums.shtml
> This means that the concrete piers where many Cesium clocks and GPS reference stations are located are bobbing up and down as if they were on a ocean, although only tens of inches.
> I think there was an earlier post saying this puts a limit (E-16?) on the ultimate quality of a clock because of it's movement.  I wonder if NIST has one of the GWR gravitymeters on a pier and uses that to discipline their fountain clocks for the elevation change of the pier or if that's done for the GPS reference antennas?
> -- 
> Have Fun,
> Brooke Clarke
> http://www.PRC68.com
> http://www.end2partygovernment.com/2012Issues.html
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