Updated The mystery of the “Wow!” signal, a radio burst recorded from outer space in the 1970s, may been solved. Or not. Not everyone is convinced.
The 72-second signal was spotted at 1,420MHz on August 15, 1977 by Astronomer Jerry Ehman at Ohio State University’s Big Ear radio telescope. It was so clear that he scribbled Wow! in the margin. It has since been postulated, as recently as last year, that it was a message from an alien species. Now there’s another theory.
In a paper [PDF] published this week in the Journal of the Washington Academy of Sciences, researchers at the Center of Planetary Science spent two years investigating the signal, and now believe it comes not from little green men (or the good ship Arbitrary leaving Earth’s orbit – as the late Iain M Banks once put in fiction), but from comets.
The team notes that there were two comets in the same area of the sky that the signal emanated from. These comets, P/2008 Y2(Gibbs) and 266/P Christensen, weren’t discovered at the time, however they did return to the same sector of space in the period between November 2016 and February 2017.