No. 30: Nov-Dec 1983
The planet earth throbs regularly every 12 sidereal hours according to gravity-wave detectors located in Geneva and Frascati, Italy. The pulsations, presumably expansions and contractions of the earth-as-a-whole, have been re-corded at both places for over a year. Pulse amplitudes are about 100 times larger than those that are expected from gravity waves, so planetary pulsations are blamed. Since sidereal time is measured with respect to the fixed stars rather than the sun, an extraterrestrial origin is possible, although no one knows what sort of cosmic force could make our planet throb like this with such precise timing.
(Anonymous; "Italians Discover Earth Throb," New Scientist, September 29, 1983.)