I just read about a discovery of a liquid water ocean on Saturn's moon Enceladus. The method used was to measure the velocity of a spacecraft as it makes a close fly-by. Gravitational anomalies will cause the spacecraft to speed up or slow down as it flies over massive objects like mountains. With three pass they now have a 3 dimensional map of density distribution. It must be very sensitive if they can tell liquid water from ice by its gravitational field. (or even rock from ice)
They say they can measure the spacecraft's velocity to 90 microns per second. They do this by measuring the Doppler sift of the transmitter. I've been trying to figure out what 90 microns/sec means in terms of frequency. But I think(?) I need to know the orbital velocity of Enceladus. -- Chris Albertson Redondo Beach, California _______________________________________________ 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.