Astrophysicist and former Department of Defense analyst Professor Antonio Paris thinks he's determined what sent the 1977 radio wave signal that lasted for 72 seconds and came from interstellar space near a group of stars known as Chi Sagittarii, reports the Guardian. Paris believes that the signal could have come from one of two comets that were in the Chi Sagittarii at the time. And no, aliens weren't broadcasting from a comet. Paris explains that comets are surrounded by clouds of hydrogen gas and that hydrogen naturally emits radio wave frequencies that match those of the 'Wow!' signal itself. Is Paris right? He'll know in 2017 and 2018 when the comets will pass the Chi Sagittarii star group again, at which point he hopes to be using a radio telescope to see if the 'Wow!' signal repeats.