RE: >H Re: Deep time and shallow time

Eugene Leitl (
Thu, 27 May 1999 18:09:37 -0700 (PDT)

Billy Brown writes:
> We've already got instruments that can pick up a mass of around
> 50 tons at a distance of a couple of miles, which ought to be good enough
> for even really picky measurements.

Really? What physical principles do these sensors utilize?