The Wow! signal owes its name to the exclamation written on a paper printout from Ohio State’s Big Ear Radio Telescope in1972 that was evidence of a strange 72-second signal that stunned astronomer Jerry Ehman, and its lasting fame to the fact that it’s never been explained and never been picked up again. A recent paper claimed to have traced the signal to the star 2MASS 19281982-2640123 in the Sagittarius constellation 1800 light-years from Earth, but it’s still a theory. Now, another astronomer has proposed to have identified Wow! as leakage from a power beam propelling an extraterrestrial spacecraft. Time to drop the mic and yell “Wow!”?
“The most observable leakage radiation from an advanced civilization may well be from the use of power beaming to accelerate spacecraft and transfer energy. Power beams are now more credible because we’re building our own: The Starshot project plans launching probes to nearby stars in this century, making power beaming a credible source concept. And power beaming is being developed for military applications, where it is termed ‘directed energy’.”
James Benford, a plasma physicist and CEO of Microwave Sciences, summarizes in Centauri Dreams the paper he’s presented to the journal Astrobiology. He compares the Wow! signal to the powerful laser beams being proposed to power laser sails to nearby stars and to the ‘directed energy’ weapons being developed by militaries to attack and destroy without explosives. In his summary, Benford proposes that leakage – energy that doesn’t directly hit the propelled object – could be powerful enough to be seen by other nearby intelligent species, and shows how it would explain the four parameters of the Wow! signal -- the power density received, the signal’s duration, its frequency and its revisit time. The last parameter is the interval until the signal is seen again and Benford explains that it’s the least discussed but possibly the strongest argument for power beam leakage.
“The Wow! observation has never recurred. I take this absence as a clue to its origin.”
Leakage of a highly directed high power beam from around the vehicle would still be powerful, explaining parameter 1. The Big Ear was fixed in orientation, rotating with the Earth, and the duration of the Wow! signal – 38 seconds – matched the duration of a model of a power beam from another star system – 36 seconds, explaining parameter 2. The Wow! Signal was at the 1.42 GHz frequency, a protected radio astronomy bandwidth, so it couldn’t be a transmission from Earth or its satellites – parameter 3. Finally, there’s the recurrence factor.
“The angle of the radiated beam with respect to the light path between the two stars is larger than the width of the beam. Thus, the beam is generally not observable from the target planetary system. If the Wow! was driving a probe to a star, that star was at that time far from the direction of the beam. Earth could accidentally receive the leakage from the beam, since stars move relative to each other. So leakage radiation from star probe launches using the Wow! beam will not be seen again from Earth. This fits the non-observations to date.”
Wow! Benford concludes that power beams are the most credible explanation for Wow! because we’re building our own, thus proving they can existence. He also builds a case for treating SETI as a search for these random power beams rather than communications signals – a case that will take a lot more convincing of the astronomy and SETI worlds focused on those types of signals.
It’s not time to drop the mic – but James Benford definitely builds a case for tossing it in the air or spinning it around on its cord (for fans of a certain age).