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<\/p>\nNew Explanations for the Enigmatic Wow! Signal
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The Wow! signal, a one-off detection at the Ohio State \u2018Big Ear\u2019 observatory in 1977, continues to perplex those scientists who refuse to stop investigating it. If the signal were terrestrial in origin, we have to explain how it appeared at 1.42 GHz, while the band from 1.4 to 1.427 GHz is protected internationally \u2013 no emissions allowed. Aircraft can be ruled out because they would not remain static in the sky; moreover, the Ohio State observatory had excellent RFI rejection. Jim Benford today discusses an idea he put forward several years ago, that the Wow signal could have originated in power beaming, which would necessarily sweep past us as it moved across the sky and never reappear. And a new candidate has emerged, as Jim explains, involving an entirely natural process. Are we ever going to be able to figure this signal out? Read on for the possibilities. A familiar figure in these pages, Jim is a highly regarded plasma physicist and CEO of Microwave Sciences, as well as being the author of High Power Microwaves<\/a>, widely considered the gold standard in its field.<\/em><\/p>\n by James Benford<\/strong><\/p>\n The 1977 Wow! signal had the potential of being the first signal from extraterrestrial intelligence. But searches for recurrence of the signal heard nothing. Interest continues, as two lines of thought continue to ponder it.<\/p>\n An Astronomical Maser<\/strong><\/p>\n A recent paper proposes that the Wow! signal could be the first recorded event of an astronomical maser flare in the hydrogen line [1]. (A maser is a laser-like coherent emission at microwave frequencies. The maser was the precursor to the laser.) The Wow frequency was at the hyperfine transition line of neutral hydrogen, about 1.4 GHz. The suggestion is that the Wow was a sudden brightening from stimulated emission of the hydrogen line in interstellar gas driven by a transient radiation source behind a hydrogen cloud. The group is now going through archival data searching for other examples of abrupt brightening of the hydrogen line.<\/p>\n Maser Wow concept: A transient radiative source behind a cold neutral hydrogen (HI) cloud produced population inversion in the cloud near the hydrogen line, emitting a narrowband burst toward Earth [1]. <\/p>\n Image courtesy of Abel Mendez (Planetary Habitability Laboratory, University of Puerto Rico at Arecibo).<\/em><\/p>\n Could aliens use the hydrogen clouds as beacons, triggered by their advanced technology? Abel Mendez has pointed out that this was suggested by Bob Dixon in a student\u2019s thesis in 1976 [2]! From that thesis [3]: <\/p>\n \u201cIf it is a beacon built by astroengineering, such as an extraterrestrial civilization that\u2028is controlling the emission of a natural hydrogen cloud and using it as\u2028a beacon, then the only way that it could be ascertained as such, is by some time variation. And we are not set up to study time variation.\u201d<\/p>\n<\/blockquote>\n How could such a beacon be built? It would require producing a population inversion in a substantial volume of ionized hydrogen. That might perhaps be done by an array of thermonuclear explosives optimized to produce a narrowband emission into such a volume [4]. Exploded simultaneously, they could produce that inversion, creating the pulse seen on Earth as the Wow.<\/p>\n Why does the Wow! Signal have narrow bandwidth?<\/strong><\/p>\n In 2021, I published a suggestion that the enigmatic Wow Signal, detected in 1977, might credibly have been leakage from an interstellar power beam, perhaps from launch of an interstellar probe [5]. I used this leakage to explain the observed features of the Wow Signal: the power density received, the Signal\u2019s duration and frequency. The power beaming explanation for the Wow accounted for all four of the Wow parameters, including the fact that the Wow observation has not recurred. <\/p>\n At the 2023 annual Breakthrough Discuss meeting, Mike Garrett of Jodrell Bank inquired \u201cI was thinking about the Wow signal and your suggestion that it might be power beam leakage. But it\u2019s not obvious to me why any technical civilization would limit their power beam to a narrow band of <= 10 kHz. Is there some kind of technical advantage to doing that or some kind of technical limitation that would produce such a narrow-band response?\u201d<\/p>\n After thinking about it, I have concluded that there is \u2018some kind of technical advantage\u2019 to narrow bandwidth. In fact, it is required for high-power beaming systems.<\/p>\n Image:<\/strong> The Wow Signal was detected by Jerry Ehman at the Ohio State University Radio Observatory (known as the Big Ear). The signal, strong enough to elicit Ehman\u2019s inscribed comment on the printout, was never repeated.<\/p>\n A Beamer Made of Amplifiers?<\/strong><\/p>\n High power systems involving multiple sources are usually built using amplifiers not oscillators, for several technical reasons. For example, the Breakthrough Starshot system concept has multiple laser amplifiers driven by a master oscillator, a so-called master oscillator-power amplifier (MOPA) configuration. Amplifiers are themselves characterized by the product of amplifier gain (power out divided by power in) and bandwidth, which is fixed for a given type of device, their \u2018gain-bandwidth product\u2019. This product is due to phase and frequency desynchronization between the beam and electromagnetic field outside the frequency bandwidth [6].<\/p>\n Therefore, for wide bandwidth, a lower power per amplifier follows. That means many more amplifiers. Likewise, to go to high power, each amplifier will have a small bandwidth. (Then the number of amplifiers is determined by the power required.) For power beaming applications, to get high power on target is essential: higher power is required, so smaller bandwidth follows.<\/p>\n So why do you get narrow bandwidth? You use very high gain amplifiers to essentially \u201ceat up\u201d the gain-bandwidth product. For example, in a klystron, you have multiple high-Q cavities that result in high gain. The high-gain SLAC-type klystrons had gains of about 100,000. Bandwidths for high power amplifiers on Earth are about one percent of one percent, 0.0001, 10-4<\/sup>. The Wow! bandwidth is 10 kHz\/1.41 GHz, about 10-5<\/sup>.<\/p>\n So yes, the physics of amplifiers limits bandwidth in beacons and power beams because both would be built to provide very high power. So, with very high gain in the amplifiers, small bandwidth is the result.<\/p>\n This fact about amplifiers is another reason I think power beaming leakage is the explanation for the Wow. Earth could have accidentally received the beam leakage. Since stars constantly move relative to each other, later launches using the Wow! beam will not be seen from Earth.<\/p>\n Therefore I predicted that each failed additional search for the Wow! to repeat is more evidence for this explanation.<\/p>\n The Wow search goes on<\/strong><\/p>\n These two very different explanations for the origin of the Wow! have differing future possibilities. I predicted that it wouldn\u2019t be seen again. Each failed additional search for the Wow! to repeat (and there have been many) is more evidence for this explanation. Mendez and coworkers are looking to see if their process has occurred previously. They can prove their explanation by finding such occurrences in existing data. These are two very different possibilities. Only the Mendez concept can be realized soon.<\/p>\n References<\/strong><\/p>\n 1. Abel Mendez,1 Kevin Ortiz, Ceballos, and Jorge I. Zuluaga, \u201cArecibo Wow! I: An Astrophysical Explanation for the Wow! Signal,\u201d arXiv:2408.08513v2 [astro-ph.HE], 2024.<\/p>\n 2. Abel Mendez, private communication.<\/p>\n 3. Cole, D. M. (1976). \u201cA Search for Extraterrestrial Radio Beacons at the Hydrogen Line,\u201d Doctoral dissertation, Ohio State University, 1976.<\/p>\n 4. Taylor, T., 1986, \u201cThird generation nuclear weapons,\u201d Sci. Am.<\/em>, 256, 4, 1986.<\/p>\n 5. James Benford \u201cWas the Wow Signal Due to Power Beaming Leakage?\u201d, JBIS<\/em> 74 196-200, 2021.<\/p>\n<\/p>\n![\"\"](\"https:\/\/mycbh.com\/Games\/spaceperium\/wp-content\/uploads\/sites\/2\/2025\/04\/Wow-Maser-geometry.jpg\")
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