There may not be many radio astronomy printouts that have achieved universal fame, but the one from Ohio State University’s Big Ear telescope upon which astronomer [Jerry R. Ehman] wrote “WOW!” is definitely one of them. It showed an intense one-off burst that defied attempts to find others like it, prompting those who want to believe to speculate that it might have been the product of an extraterrestrial civilization. Sadly for them the Planetary Habitability Laboratory at the University of Puerto Rico at Arecibo has provided an explanation by examining historical data from the Arecibo telescope.
The radio signal in question lay on the hydrogen line frequency at 1420 MHz, and by looking at weaker emissions from cold hydrogen clouds they suggest that the WOW! signal may have come from a very unusual stimulation of one of these clouds. A magnetar is a type of neutron star which can create an intense magnetic field, and their suggestion is that Big Ear was in the lucky position of being in the right place at the right time to see one of these through a hydrogen cloud. The field would excite the hydrogen atoms to maser-like emission of radiation, leading to the unexpected blip on that printout.
There’s a question as to whether speculation about aliens is helpful to the cause of science, but in answer to that we’d like to remind readers that we wouldn’t be talking about magnetars now without it, and that the WOW! signal was in fact part of an early SETI experiment. Better keep on searching then!
Meanwhile readers with long memories will recollect us looking at the WOW! signal before.
