> -----Original Message----- > From: time-nuts-boun...@febo.com > [mailto:time-nuts-boun...@febo.com] On Behalf Of Björn Gabrielsson > Sent: Friday, December 12, 2008 1:55 PM > To: bro...@pacific.net; Discussion of precise time and > frequency measurement > Subject: Re: [time-nuts] time-nuts Digest, Vol 53, Issue 46 > > > On Thu, 2008-12-11 at 14:38 -0800, Brooke Clarke wrote: > > Hi Mark: > > > > I think it's out of date. > > > > The current method is to drop an optical corner cube > (retro-reflector) > > in a vacuum and using a laser measure the distance it moves (which > > requires a reasonably good source of time. > > http://www.ngs.noaa.gov/GRD/GRAVITY/ABSG.html > > > > Have Fun, > > > > Brooke Clarke > > http://www.prc68.com > > > > Mark Sims wrote: > > > The quintessential gravity meter (Worden Gravity Meter by > Texas Instruments)... still being made after 60 years or so: > > > http://www.mssu.edu/seg-vm/pict0246.html > > Spring based (relative) gravimeters are NOT yet dead... > > http://large.stanford.edu/courses/ph210/lee1/ >
See, there *is* a need for garage Liquid Helium plants... _______________________________________________ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.