An approximation to determine the source of the WOW! Signal

Here is the abstract and introduction of a paper forwarded by Leif Svalgaard

Alberto Caballero

In this paper it is analysed which of the thousands of stars in the WOW! Signal region could have the highest chance of being the real source of the signal, providing that it came from a star system similar to ours. A total of 66 G and K-type stars are sampled, but only one of them is identified as a potential Sun-like star considering the available information in the Gaia Archive.

This candidate source, which is named 2MASS 19281982-2640123, therefore becomes an ideal target to conduct observations in the search for potentially habitable exoplanets. Another 14 potential Sun-like stars (with estimated temperatures between 5,730 and 5,830 K) are also found in the region, but information about their luminosity and radius is unknown.
Keywords: WOW! Signal, SETI, Search for Extraterrestrial Intelligence, interstellar radio message.


As of October 2020, the WOW! Signal remains the strongest candidate SETI signal. It has been suggested that the signal was produced by hydrogen clouds from Comets 266/P Christensen and P/2008 Y2 (Paris and Davies, 2015). However, this hypothesis has been dismissed by the scientific community, and the source of the signal remains unknown.

Despite the WOW! Signal never repeated, the key aspect was its duration. The signal lasted for 72 seconds, but since this was the maximum amount of time that the Big Ear radio telescope was able to observe, it is likely that the signal would have lasted longer.

The main problem, however, is that the signal never repeated. Follow-up observations of the area conducted by many observatories during several years never detected another signal (Gray and Ellingsen, 2002). Nonetheless, the fact that the signal never repeated, does not necessarily discard that it was produced by extraterrestrial intelligence.

In fact, if we analyse the history of (the few) radio signals that humanity have sent to several targets in the hope of contacting a civilization, none of those transmissions had a long duration or were repeatedly sent for a long time. An extraterrestrial civilization could have opted to behave in a similar manner.

Few attempts have been made to determine the exact location of the WOW! Signal due to the difficulty involved. Despite it was detected in just one of the two feed horns of the radio telescope, the data was processed in a way that does not allow us to determine which of the feed horns actually received the signal.

The other reason that makes difficult to determine the exact source is the high uncertainly in declination: 20 arcminutes. The following image shows an approximation of the two sections of the sky that could contain the source of the signal, each of them with thousands of stars.

Figure 1: In red, the two regions where the WOW! Signal could have originated
Source: Pan-STARRS/DR1

The coordinates of the signal are RA: 19h25m31s ± 10s (for the positive horn), 19h28m22s ± 10s (for the negative horn), and DEC: −26°57′ ± 20′, both in J2000 equinox (Ehman, 1997). In this article an attempt is made to create a list of the possible sources of the signal assuming that, if it was produced by an extraterrestrial civilization, their exoplanet is similar to Earth.

Full paper here.

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Joel O'Bryan
November 26, 2020 10:55 pm

“The fact that all the stars in both samples are farther than 500 light years away is consistent with Claudio Maccone estimations that the closest communicative civilization is no closer than 500 light years away (Maccone, 2012).”

Lots of biological things change in 500 years, some completely gone.
Imagine if “they” had communicated with passenger pigeons for thousands of years, but then in 400 years all they’ll get is silence. Then what?
Maybe though on Passenger Pigeons… they didn’t go extinct. They just emigrated away from this nuthouse.

Reply to  Joel O'Bryan
November 27, 2020 6:44 am


ht/ Douglas Adams

Bill Parsons
November 26, 2020 11:12 pm

Perhaps Leif could summarize the significance of the WOW! signal in language mere mortals could understand. Why is this noise coming from Galactic center deserving of the expletive “Wow”, and what does it have to tell us some forty years later.

Wikipedia’s explanations of technical matters are about as useful as the number grid with the astronomer’s “Wow” written on it.

Adam Gallon
Reply to  Bill Parsons
November 27, 2020 1:14 am
November 26, 2020 11:39 pm

The signal ended because of a climate catastrophe? They hit a tipping point?

Reply to  Ralph Dave Westfall
November 27, 2020 4:31 am

Awe crap! Don’t give them any new ideas…. It’s bad enough the WOW ™ caused voting machines to flip votes in select locations and gave Joe Biden a possible win. Now you know why they liberal “scientists” can find the signal again. It happens on election day once every 4 years for several hours. Thankfully back in 2016, the aliens were 1 day late.

Reply to  Ralph Dave Westfall
November 27, 2020 6:47 am

Alien cultural marxists banned radio and now allow only messenger-runners.

November 27, 2020 12:18 am

Wow signal
comment image

Reply to  Vuk
November 27, 2020 3:13 am

“The signal intensity was measured as signal-to-noise ratio, with the noise (or baseline) averaged over the previous few minutes. The signal was sampled for 10 seconds and then processed by the computer, which took 2 seconds. Therefore, every 12 seconds the result for each frequency channel was output on the printout as a single character, representing the 10-second average intensity, minus the baseline, expressed as a dimensionless multiple of the signal’s standard deviation”!_signal#/media/File:Wow_signal_profile.svg
Is this signal generated by an advanced civilisation?
I would say not.
Speaking with my cyclomaniac’s hat on, we know there is wide spectrum of radio frequencies coming from space, one of the best known is the F10.7 cm solar flux, then there is the Jupiter radio noise with frequencies between 10 and 40 MHz, and millions maybe billions of others drifting through our galaxy and nearby universe generating the background noise.
Probability is that from time to time some of the signals of similar periodicity will fall into phase and enhance overall amplitude, generating an individual burst standing out well above the background noise. If so it is likely that rise and fall of signal’s standard deviation would follow the Gaussian distribution as is the case with this ‘wow’ signal.
On a positive note, in February the NRAO and SETI have have agreed to develop a black box riding piggyback on the Very Large Array (VLA) radio telescope processing its background noise for the so called “technosignatures” signals.

Coeur de Lion
November 27, 2020 12:19 am

They’re on their way and will invade in 2520.

Moderately Cross of East Anglia
November 27, 2020 1:03 am

The Wow signal has always fascinated me and seems the only instance so far as I know of something which might just be some kind of transmission from an “alien” source: though of course it is equally likely to have some more mundane explanation we haven’t thought of yet. But we should take some encouragement and keep on looking.

For the terminally insane, it was clearly a signal to all the reptiles agents on Earth to start the conspiracy campaign that would undermine our civilisation by claiming our technology was causing climate change and reduce us to living in medieval squalor so that when THEY arrive they can steal all our fossil fuels without resistance. The dates for the Wow signal and the rise of eco-fascism coincide and as we all know correlation always equals causation. Right?

Reply to  Moderately Cross of East Anglia
November 27, 2020 3:08 am

With a 500 year lag. Just like the CO2 lag. Odd coincidence?

Reply to  Moderately Cross of East Anglia
November 27, 2020 4:35 am

The second coming has been imminent for every generation of the last 2000 years+. The signs and wonders say so.

Reply to  AndyHce
November 27, 2020 5:41 am

Nostrodamus predicted a prophet would post a strange pronouncement to the world on November 27, 2020 at 4:35am that would usher in the end of the world. Watts up with that??!!

Tom in Florida
Reply to  BallBounces
November 27, 2020 12:24 pm

4:35 AM where?

Reply to  Tom in Florida
November 28, 2020 1:52 pm

Tom — look up, look way… , well, look above my post.

Ed Zuiderwijk
November 27, 2020 1:50 am

Hm. Don’t want to spoil the party but as one who was involved in identifying optical counterparts to X-ray sources in the 70s and 80s I am not impressed. The ‘error boxes’ are probability contours. Many counterparts were found outside the ‘error box’ because, as a colleague once quipped, there is so much more space outside than inside. Second, the assumption of a solar type star is a huge projection. Whatever it was, it was a high energy phenomenon and looking for an object with unusual spectral of brightness characteristics would be a more promising approach.

Pat Frank
Reply to  Ed Zuiderwijk
November 27, 2020 7:15 am

Ed, is a natural hydrogen maser possible?

November 27, 2020 3:05 am

They narrowed it down to 1 specific star and 66 possible, and say that is a very good exoplanet search region.
They are using the new Gaia database.
Maybe someone has set a target Kepler exoplanet list already?

Beware, Vogon poetry is well known to have serious effects (ask Arthur Dent), and they like to build highways right through your solar backyard.

Reply to  bonbon
November 27, 2020 4:11 am

What makes contacting more advanced civilisations such a good idea, anyway? The assumption that they would, necessarily, share our values, or own idea of empathy, seems to be very dodgy indeed. Vogon or not.

But I’m fairly relaxed about it, as a better-grounded assumption would be that any civilisation advanced enough to interact with us already knows about us, without being hailed.

November 27, 2020 4:12 am

It’s the last message sent by the remains of the Navina ship’s crew to warn Earthpeople about a reptilian species that destroys everything it encounters. It comes from a megamasesr galaxy 300 million light years away, due west of Earth. The battery on the satellite that sent the message was running out of juice, and that was the last burst. They may show up before Coeur de Lion’s best guess of 2520.

We were warned! All those freakazoid movies from the 1950s and 1960s, including “Day of the Triffids” were warnings! We were warned!!

Pat Frank
Reply to  Sara
November 27, 2020 7:23 am

I think it’s the continuous bombardment with broadcast 1950s sitcom re-runs, Sara. They’re irritated to a causus belli. We’ve been warned. One more Life of Riley, and we’re toast.

Rich Davis
Reply to  Pat Frank
November 27, 2020 10:08 am

Of course the inverse square law on a primitive low power VHF signal probably rules out anybody far from the earth’s surface ever detecting it, but otherwise your point is an excellent one, Pat.

Reply to  Pat Frank
November 27, 2020 12:22 pm

But they know how to regrade the degraded VHF signals! Count on it! And having a rooftop antenna makes you even more of a target! What if they think the cell towers are aiming at THEM???

And they probably know how to regrade the UHF and the MCWVs, too, especially when they originate from VFWs set up in the garage’s 2nd floor!

We’re doomed! Doomed, I tellya!

Can i have some ice cream?

Reply to  Sara
November 27, 2020 7:55 pm

Do you guys have any idea about what pounding “a potential invasion by space aliens” (something like that) might do to the mindless persons who have fallen hip-deep into the morass that is the ecohippie/green movement? Everything, from those telephony/commlink satellites that Tesla launched a few weeks ago to another night rocket launch that looks like an invading party landing could make them believe we’re under siege.

Might be even easier if the ecohippies and greenies could be convinced that any plants they bring with them are genetically designed to take over and wipe out all Earth species of plants so that the aliens can grow corn here. Point out how many cornfields we already have, and…. well, they may already be here….

The Doctor
November 27, 2020 4:46 am

Just as the whole Loch Ness Monster craze was kicked off by a hoax and continues to this day, despite the fact that the hoax was revealed, the scientific community lends credence to a 3 letter word some guy scrawled next to some lines on a graph from a primitive audio detecting device from 50 years ago.

Mark - Helsinki
November 27, 2020 5:38 am

” Nonetheless, the fact that the signal never repeated, does not necessarily discard that it was produced by extraterrestrial intelligence.”

Any broadcast environment where the wow signal came from would have given us more broadcast signals of some kind, varying in type and quality.

Granted it’s all they have to cling to, tho it’s not a WOW signal, its merely a signal that is thus far imo, willfully not attributed to natural causes.

Reply to  Mark - Helsinki
November 27, 2020 6:10 am

I’m not saying you are wrong Mark. Personally I think it was most likely some kind of natural signal or perhaps a stray signal from earth. But what if it was from a moving alien object? For example some kind of emergency signal from a moving alien craft and for just a few minutes the signal accidentally was pointed in our direction? For example a flying saucer that was out cruising just beyond the orbit of Pluto and got a flat tire and was calling the AAA for roadside assistance?

November 27, 2020 5:45 am

Meanwhile we’re losing our biggest ear capable ti hearing another WOW:

Walter Sobchak
Reply to  Yooper
November 27, 2020 11:06 am
Rich Davis
November 27, 2020 5:51 am

The “wow” is best applied to those who, decade after decade, cling to their certainty that the galaxy is (gotta be, just hassta be) teeming with life despite more than half a century of finding no evidence. We don’t need no stinkin’ evidence. We BELIEVE!

Tom in Florida
Reply to  Rich Davis
November 27, 2020 7:08 am

Wow, a whole half century! What’s that, about 50 light years in all directions? Not much of a sample.

Rich Davis
Reply to  Tom in Florida
November 27, 2020 7:36 am

Tom think about what you just said and I’ll wait for your retraction without ridiculing you.

It is pretty early in Florida and maybe the coffee hasn’t kicked in.

Rich Davis
Reply to  Rich Davis
November 27, 2020 8:35 am


If a civilization on a planet 500 light years from earth sent a signal in 1492, what year did it reach earth?

If a civilization on a planet 60,000 light years from earth sent a signal 59,972 years ago, what year did it reach earth?

Did all alien civilizations suddenly start broadcasting the day humans started listening? How did they manage to do that?

If “I Love Lucy” premiered on Oct 15, 1951, how many light years away are the furthest planets currently receiving the signal? Is that answer at all relevant?

Thomas Gasloli
Reply to  Rich Davis
November 27, 2020 12:22 pm

“Did all alien civilizations suddenly start broadcasting the day humans started listening? How did they manage to do that?”

Thank you, that made me laugh. Unfortunately the true believers don’t understand confirmation bias.

Tom in Florida
Reply to  Rich Davis
November 27, 2020 12:44 pm

My point was that we have not heard any response to our transmissions over the last 50 years. Any technological civilization within those 50 light years would certainly know about us.
Whether they choose to respond or not is another question. And whether they can respond and do not or they are not capable of receiving and transmitting yet does not preclude that the galaxy is teaming with life.

Rich Davis
Reply to  Tom in Florida
November 27, 2020 1:22 pm

SETI is not about sending messages, it’s about listening. In principle, signals could originate from millions of light years away, of course sent millions of years ago and not sent as a result of any prior detection of our signals.

The whole concept has always been an absurd waste of money since we would almost certainly not be able to detect any alien signal unless it was intentionally directed toward us with incredible power for the purpose of announcing their existence—an expensive project to what end?

I’m not saying that the failure of SETI proves anything other than the lack of intelligence in terrestrial governments.

Tom in Florida
Reply to  Tom in Florida
November 27, 2020 4:19 pm

The presumption that no signal detection concludes anything about life in the galaxy falls short. If a civilization did not have the capability to emit artificial signals we can detect until recently, how would we know they are there? That would be saying life did not exist on Earth 20,000 years ago, or 65 million years ago. The point being that we can only make statements about the existence of other life in the galaxy over a very small, relatively close area around us.

Rich Davis
Reply to  Tom in Florida
November 28, 2020 7:04 am

Tom, you’re right that the absence of evidence is not necessarily evidence of absence. In this case especially so, since SETI is not fit for purpose.

I think you missed my last comment, so I’ll repeat it. “I’m not saying that the failure of SETI proves anything other than the lack of intelligence in terrestrial governments.”

But people who cling to the wow signal which is clearly a natural phenomenon, are demonstrating an emotional response. They for some reason are emotionally invested in the idea that there are myriad civilizations out there.

Personally I don’t care one way or the other. It’s just as interesting to wonder why we’re alone as to discover that life is common.

Rich Davis
Reply to  Tom in Florida
November 28, 2020 7:37 am

Oh and Tom you’re still making a fundamental error.

There is no strict distance limitation to detecting alien signals if they were sent for the purpose of announcing their presence, (sufficiently focused, directed, and high power), but there is a big problem that if technological civilizations are not long-lived, and/or their period of time using inefficient communication technology is short, then the probability that we will be at the right distance from them relative to how long ago they emitted, to have their signals reach us in the very short period of time we are listening is almost nil.

Those star systems closest to us have a better chance of detecting our signals and vice versa (because of the inverse square law), but it would likely have to be a multi-generational exercise for us to have a two-way “conversation” with any alien civilization. So in that interactive sense, only the closest neighbors are practical. However, there is no reason to assume that any civilizations would develop in sync. Maybe a planet around alpha Centauri had an advanced civilization that ended 20,000 years ago and another nearby star system will have a civilization that won’t be able to detect us for a billion years. There are many more stars further away, so maybe it is more likely to detect a signal too far away that we could ever have a two-way conversation.

Reply to  Rich Davis
November 27, 2020 9:58 pm

Not really. The trouble is that having drawn that conclusion they fail to reason it through. Even if the galaxy is teaming with life, and even if a solid fraction are intelligent, and even if a solid fraction of that fraction are technologically inclined, what are the odds that they are as “advanced” as we are, as optimistic as SETI advocates are? Even here on earth it is arguable that there is more than one intelligent species, yet only one has settled on technology and culture as a primary means of survival.

November 27, 2020 7:31 am

I crunched SETI data almost from the start but when you think about it, receiving a signal is very unlikely. The inverse square law indicates you must have a highly direction transmitter if you are to be heard or you must run extremely powerful transmitters which would be very costly to operate. If you consider earth, we have only transmitted a short message for a day or so then remained silent. There isn’t much motivation for another race to transmit other than they require help that they think another race might be able to provide.
Even if you have very powerful transmitters, our ability to hear is pretty much limited to a few hundred light years of distance. This greatly reduces the number stars to chose from.
If the transmission is highly directional, we would have to be looking in the right direction at the right time. SETI data from Arecibo is only obtained when the antenna is down for service. The receiver is positioned and locked in place. As the earth turns, the rotation of the earth allows the antenna to scan the sky. This results in a narrow strip of sky to be scanned and then the data is crunched by many volunteers looking for a needle in a haystack.
SETI is the best we have on the limited budget and the fact that we may have captured even one event is unexpected.
SETI’s budget was so limited that they accumulated a massive amount of data but due to limited hardware were never able to finish the processing. They have shut down the processing of new data and are now in the process of shifting through the massive accumulation of data looking for a second event. Stay tuned because a paper will be written on the results eventually.

Tom Abbott
November 27, 2020 8:50 am

I would think that if it were an advanced civilization trying to send a signal for some reason, they would send a signal that is clearly manipulated by intelligent beings, and they would send it more than once.

A one-time signal sounds like a natural phenomenon probably caused it.

Let’s get some really big telescopes in orbit and look all these stars over.

Rich Davis
November 27, 2020 9:52 am

Did you and the rest of the SETI Jedi just now discover the inverse square law? If it was always “very unlikely”, is that what you were saying even when you first started crunching the numbers “almost from the start”, or did you decide to spend a lot of time and money without first considering feasibility?

Well it is a government project. Flawed science in the service of proving a hypothesis preordained. That’s what government grants are for, right?

November 27, 2020 11:33 am

It may be a mistake to assume that an advanced species is going to leak an ever expanding sphere of radio signals into the universe. It could well be that after a brief start-up flicker it switches to more efficient cables or to carefully directed beams to and from satellites.

Going dark would not necessarily mean catastrophe. It could mean that they just advanced to the next level. We seem to be in the process of doing that just now.

Rich Davis
Reply to  Rachelle
November 27, 2020 12:52 pm

Yes, that makes good sense. Why would they waste energy?

But surely we could overcome that with vastly more spending? Every problem can be solved by having government spend 100 times more than conservatives are willing to waste.

Then 50 years later, the people who wasted the grant money just explain that of course we never expected to get lucky enough to detect anything. What did you expect when you weren’t willing to spend your entire GDP?

Thomas Gasloli
November 27, 2020 12:25 pm

Which tax payers are getting stuck with this SETI budget? Seems like a prime candidate for a cut.

November 27, 2020 12:29 pm

Advanced civilisations would not use radio transmitters to communicate at the light-years distances, it requires huge input power and messages are not secure.
A technically advance civilisation would use totally secure, one to one, low power infinite distance quantum mechanics ‘entangled particles’ transceivers.

Bruce Cobb
November 27, 2020 12:57 pm

The aliens didn’t realize the mic was on. Oopsie!

Kevin kilty
November 27, 2020 1:49 pm

I have never understood the belief that our TV/Radio broadcasts might be intercepted by some advanced civilization and deciphered. The channel capacity of free space over the distance from Earth to say Pluto is just about nil. Even assuming a very high powered transmitter, and a background at the temperature of the cosmic background radiation, any error-free signal would have to have a very narrow bandwidth. The actual bandwidth of broadcast TV or radio renders the whole discussion moot.

Reply to  Kevin kilty
November 28, 2020 2:48 am

>any error-free signal would have to have a very narrow bandwidth

Some form of spread spectrum is more likely. And we’ve never listened for that.

Them most detectable signal Earth has ever sent are from deep space search radars. The Arecibo telescope used to radar image asteroids. The very powerful beam didn’t stop at the asteroid, and if the beam hit a listening planet, it’s unlikely the same planet got hit a second time. Leaving some alien astronomer wondering about their own “Wow!”.

I suspect radar transmission have their on transmission window. Long distance radars are now more likely to be spread spectrum or chirped. Both techniques act as a power multiplier.

Lawrence E Todd
November 27, 2020 6:28 pm

SETI has found the WoW (World of Warcraft) signal!

November 28, 2020 6:23 am

“As of October 2020, the WOW! Signal remains the strongest candidate SETI signal.”

Earth based radio receivers.

“As of October 2020, the WOW! Signal remains the strongest candidate SETI signal.”

Doesn’t sound they’ve proven the signal was not of Earth origin; signal refracted/reflected within the atmosphere; signal from a Earth orbiting instrument.

Extraordinary claims require extraordinary evidence/proof.

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