[time-nuts] Cesium vs H Maser clocks

[Hal Murray]

> Someone asked what a frequency time standard cam calibrate besides a
> clock. Gravity is, or was, measured by throwing a corner cube into the
> air (vacuum) and using a laser interferometer, timing its
> acceleration as it fell back. All of that can be calibrated from a
> frequency standard, so unlike volts and things gravity is one
> variable that frequency/time can be used to define. Although I dont
> think you will find a frequency/gravity transducer on fleabay. 

My head hurts.    What does relativity do to a laser interferometer?

Clocks are already good enough that they need to correct for 
elevation/gravity.  Is this getting circular?


In case anybody hasn't read it recently...

      Time Too Good to Be True, Daniel Kleppner
      Physics Today, March 2006, page 10

http://scitation.aip.org/journals/doc/PHTOAD-ft/vol_59/iss_3/10_1.shtml
http://www.physicstoday.org/vol-59/iss-3/pdf/vol59no3p10_11.pdf

The html version needs cookies.  The pdf version needs a non-old pdf reader.



-- 
These are my opinions, not necessarily my employer's.  I hate spam.