On August 23rd, 1924 Mars passed as close to the Earth as it has in over 60,000 years, with the exception of the fairly recent August 27, 2003 encounter. It won’t be that near again until 2287.
It seems the Chief of Naval Operations Edward W. Eberle of the US Navy thought life on Mars may attempt to communicate with the Earth during that event and sent a telegraph out instructing all Naval stations to monitor the airwaves for any unusual transmissions from August 21st to the 24th.
“NAVY DESIRES COOPERATE ASTRONOMERS WHO BELIEVE POSSIBLE THAT MARS MAY ATTEMPT COMMUNICATION BY RADIO WAVES WITH THIS PLANET WHILE THEY ARE NEAR TOGETHER THIS END ALL SHORE RADIO STATIONS WILL ESPECIALLY NOTE AND REPORT ANY ELECTRICAL PHENOMENON UNUSUAL CHARACTER AND WILL COVER AS WIDE BAND FREQUENCIES AS POSSIBLE FROM 2400 AUGUST TWENTY FIRST TO 2400 AUGUST TWENTY FOURTH WITHOUT INTERFERRING WITH TRAFFIC”
Professor David Todd, former head of the Amherst College astronomy department, was the driving force behind getting the Army and Navy to report any radio messages they may have detected, but failed to silence the country’s private radio broadcasters.
An ad was run in Popular Radio Magazine concerning the possibility that Mars would try to contact us during that time period.
Strange signals were reported from several sources. Radio operators in Vancouver reported that they were receiving a series of “four groups of dashes in groups of four”. In London a listener reported “harsh notes” of an unknown origin. WOR engineers in Newark, New Jersey reported similar sounds at nearly the same wavelength. A Bostonian reported a strange ringing, ending with an abrupt “zzip”.
These were all explained away in some form and the general consensus was that nothing but static could be heard over the radio waves for those days in August. If Mars tried to contact us, we missed it.
This was all 14 years before Orson Welles’ famous “War of the Worlds” broadcast.