Hi Mark: I think it's out of date.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 > > > ------------------------------------------ > Geologists measure gravity to get the density of of the underlying rocks. I > saw a neat topo map of the San Francisco peninsula at one of the USGS open > houses. The contours were rock density rather than elevation. > > Of course, they had to correct for elevation. When I asked how they got the > elevation, the guy smiled: "From the sewer people". > > They had the instrument on display. It wasn't very big, say a cubic foot. > Maybe they will have it out at the next open house so I can look closer. > > > _________________________________________________________________ > Send e-mail anywhere. No map, no compass. > http://windowslive.com/Explore/hotmail?ocid=TXT_TAGLM_WL_hotmail_acq_anywhere_122008 > _______________________________________________ > time-nuts mailing list -- [email protected] > To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > and follow the instructions there. > > _______________________________________________ time-nuts mailing list -- [email protected] To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
