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Swift
2016-Jan-12, 08:34 PM
NewScientist.com (https://www.newscientist.com/article/dn28747-famous-wow-signal-might-have-been-from-comets-not-aliens/)


On 15 August 1977, radio astronomers using the Big Ear radio telescope at Ohio State University picked up a powerful signal from space. Some believe it was our first interception of an alien broadcast. Now it seems something closer to home may have been the source: a pair of passing comets.

The signal – known as the “Wow! signal” after a note scribbled by astronomer Jerry Ehman, who detected it – came through at 1420 megahertz, corresponding to a wavelength of 21 centimetres. Searchers for extraterrestrial transmissions have long considered it an auspicious place to look, as it is one of the main frequencies at which atoms of hydrogen, the most common element in the universe, absorb and emit energy. What’s more, this frequency easily penetrates the atmosphere.

Antonio Paris, a professor of astronomy at St Petersburg College in Florida, thinks the signal might have come from one or more passing comets. He points the finger at two suspects, called 266P/Christensen and P/2008 Y2 (Gibbs). “I came across the idea when I was in my car driving and wondered if a planetary body, moving fast enough, could be the source,” he says.

Comets release a lot of hydrogen as they swing around the sun. This happens because ultraviolet light breaks up their frozen water, creating a cloud of the gas extending millions of kilometres out from the comet itself.

If the comets were passing in front of the Big Ear in 1977, they would have generated an apparently short-lived signal, as the telescope (now dismantled) had a fixed field of view.

To test his idea, Paris proposes looking at the same region of space when the comets are back. Comet 266P/Christensen will transit the region first, on 25 January 2017, then P/2008 Y2 (Gibbs), on 7 January 2018. An analysis of the hydrogen signal of the comets should reveal if he is correct.

Buttercup
2016-Jan-12, 08:40 PM
Oh sure it was a pair of passing comets. :hand: Everyone knows this is just another cover up... :shifty:

Spacedude
2016-Jan-12, 09:43 PM
Well it sure beats the original cover up story of being an Earth source ;)

Buttercup
2016-Jan-12, 09:58 PM
Well it sure beats the original cover up story of being an Earth source ;)

It was Bigfoot? :)

Or a passing flock of vampire bats...

slang
2016-Jan-12, 11:08 PM
Electric comets? *runs*

It would be nice to put this piece of mystery to rest.

John Mendenhall
2016-Jan-12, 11:23 PM
Electric comets? *runs*

It would be nice to put this piece of mystery to rest.

No way. Obviously alien spaceships covertly observing the Earth by pretending to be comets!

DaveC426913
2016-Jan-13, 01:21 AM
OK, but all seriousness aside.

Does "a pair of passing comets" mean
a] the signal was caused by the combination of both comets
b] the signal was caused by a comet, we're just not sure which one?

In short, why two?

slang
2016-Jan-13, 06:08 AM
OK, but all seriousness aside.

Does "a pair of passing comets" mean
a] the signal was caused by the combination of both comets
b] the signal was caused by a comet, we're just not sure which one?

In short, why two?

That's in the preprint (http://planetary-science.org/wp-content/uploads/2016/01/Paris_Davies-H-I-Line-Signal.pdf). Both comets were very close to the location of the signal. The signal's location has an uncertainty due to how the receiver works. Either comet, or them both, could be the source of the signal.

slang
2016-Jan-13, 10:24 AM
There's one part in the conclusion part of the preprint that I don't understand. Or rather, I don't understand why that line is in that part of the paper, I don't see the connection to any of the main text. It is the part from "Additionally" to "leading beam".

ToSeek
2016-Jan-13, 03:31 PM
Moved from Life in Space to Astronomy - with a redirect - as a more appropriate location since it's more about an astronomical explanation than an exobiological one.

Ross 54
2016-Jan-13, 11:13 PM
An interesting idea. Some skepticism has been expressed, though, about there being enough radio energy from comets to account for the quite strong wow signal. Comets don't seem to be strong emitters on the neutral hydrogen line, the frequency where the wow signal was detected. There may simply not have been sufficient radio energy to account for the wow signal, which was very strong.

Then, too, the wow signal appeared in only one of the two antenna beams of the 'Big Ear' radio telescope. It was almost as if the signal turned itself off after passing through the first beam, and before encountering the second. Comets should probably have been received in both beams, especially considering the apparent high power of this signal.

Superluminal
2016-Jan-13, 11:48 PM
Comets pass through the inner solar system on fairly regular basis. If the wow was produced by a comet, seems likely we would have picked up more of them in the years since.

Ross 54
2016-Jan-14, 03:27 AM
The wow signal had a strength of 30 sigma, surprisingly strong, hence its name. If comets can do that, and given the extent of their comae, its hard to understand how they aren't already known to be strong radio sources.

Romanus
2016-Jan-17, 07:16 PM
Will only echo that I think we'd hear about a lot more radio comets if this were the case.

slang
2016-Jan-17, 09:22 PM
It's likely my fault as layman searcher but on ADS I can't quickly find a paper on comet radio emissions. The preprint doesn't link any relevant studies either.

publiusr
2016-Jan-22, 07:21 PM
iced up bracewell probe ;)

I wonder it its trajectory might match up with the Teton bolide--that did a perfect aerobrake to do a resonant return--also from the 1970s...

Extravoice
2016-Jan-22, 07:40 PM
Did I read that right?

They wanted to find aliens, so they decided to tune their radio to a frequency matching the most naturally occurring noise?

I must be misunderstanding that.

DaveC426913
2016-Jan-22, 08:04 PM
Did I read that right?

They wanted to find aliens, so they decided to tune their radio to a frequency matching the most naturally occurring noise?

I must be misunderstanding that.

You are not reading it wrong. This has long been a common technique. It is nicknamed "the water hole", partly because it is closely associated with the hydrogen and hydroxyl spectral lines, but also as a play on words for a place where intelligent species might gather.


https://en.wikipedia.org/wiki/Water_hole_(radio)
.
.

Extravoice
2016-Jan-22, 10:03 PM
According to the wiki link DaveC42691 posted above,

The waterhole, or water hole, is an especially quiet band of the electromagnetic spectrum...
(emphasis added)

So it is actually the opposite of my assumption that it would be the naturally noisiest part of the spectrum.

Kebsis
2016-Apr-21, 06:51 PM
Hi. I'm sorry to resurrect this old thread, but I have a question regarding the Wow signal I was hoping someone here could shed some light on.

While discussing the article linked above with someone else, it occurred to me that I had once been given a possible explanation for the Wow signal, but I don't really remember much about where I heard it. I may have just been a comment on an article about the signal I read years ago or something like that. And I can't find anything similar on the internet currently. So, take it for what it's worth.

That said, what I vaguely recall is someone who claimed to be familiar with the operations at Big Ear saying that data from the IBM computer that the listening array used was stored on a type of punched-card memory system. These cards would fill up with data and have to be replaced, a job usually relegated to undergrads from the University, and someone doing that job who knew the system could potentially pre-punch one of the fresh cards to 'spoof' a signal similar to what was dubbed the Wow signal.

Now, someone I was chatting with on another site said that the data for the signal was a direct printout, and that the punched-cards in question were something unrelated, causing me to doubt my memory of what I read (or at least, the reliability of whoever was writing it). But, if the system was using the cards as 'memory', would the numbers on the print-out be coming from the cards? Does any of this make sense at all? I was hoping someone who is familiar with the system used at Big Ear could shed some light on it for me.

Thanks, and sorry for the vague question here, that I'm sure sounds very leading. But this will bug me for the rest of the week if I don't get some closure. :confused:

DaveC426913
2016-Apr-21, 07:19 PM
That said, what I vaguely recall is someone who claimed to be familiar with the operations at Big Ear saying that data from the IBM computer that the listening array used was stored on a type of punched-card memory system. These cards would fill up with data and have to be replaced, a job usually relegated to undergrads from the University, and someone doing that job who knew the system could potentially pre-punch one of the fresh cards to 'spoof' a signal similar to what was dubbed the Wow signal.

Now, someone I was chatting with on another site said that the data for the signal was a direct printout, and that the punched-cards in question were something unrelated, causing me to doubt my memory of what I read (or at least, the reliability of whoever was writing it). But, if the system was using the cards as 'memory', would the numbers on the print-out be coming from the cards? Does any of this make sense at all? I was hoping someone who is familiar with the system used at Big Ear could shed some light on it for me.


The wow signal is indeed a printout, with hand-written note next to it. At least, if one is to take the reports at face-value, considering the age of this story.

One would not use punch cards as memory, one uses them as the source for the program itself. A saboteur would have to rewrite part of the program, before it is run, to get it to specifically cause such an output - and cause only a single artifact in a single run, and only occurring once (they looked for it again 50 times). Can't really see how this might be done practically without some concerted effort and subsequent coverup of sabotaged code.

https://upload.wikimedia.org/wikipedia/commons/thumb/d/d3/Wow_signal.jpg/300px-Wow_signal.jpg

mkline55
2016-Apr-21, 08:00 PM
The wow signal is indeed a printout, with hand-written note next to it. At least, if one is to take the reports at face-value, considering the age of this story.

One would not use punch cards as memory, one uses them as the source for the program itself. A saboteur would have to rewrite part of the program, before it is run, to get it to specifically cause such an output - and cause only a single artifact in a single run, and only occurring once (they looked for it again 50 times). Can't really see how this might be done practically without some concerted effort and subsequent coverup of sabotaged code.

https://upload.wikimedia.org/wikipedia/commons/thumb/d/d3/Wow_signal.jpg/300px-Wow_signal.jpg

Nice response. Just one thing, though. Punch cards were one form of WORM (Write Once Read Many) memory. They could store code or data just fine. They could also be sabotaged quite easily. We always had to flip through a presumably blank stack of cards to be sure someone hadn't playfully stuck in one that was already punched. It might have been possible for Big Ear to use them for storing data, but unlikely, since there were better techniques at the time.

Kebsis
2016-Apr-21, 08:50 PM
Thank you for your replies. But, as I was discussing this yesterday with someone else, I had already taken a look at the Big Ear website. It would seem that it was capable of saving information on punch cards, at least at some point in the process (the following taken from http://www.bigear.org/oldseti.htm):


A number of search algorithms were run simultaneously, including searches for both isolated pulses and continuous signals which rose and fell in intensity in just the predicted way (for a continuous, narrowband signal) as they passed through the antenna beams. The highly processed output data were printed every twelve seconds for all fifty channels. Signals the computer thought were "interesting" were also flagged and saved on punched cards for later analysis.

That would seem to indicate that this was only done in the case of an unusual result, in which case it wouldn't matter since the printout would be the main source of the information. But, I was wondering if anyone here was more familiar with the system used then and could say whether punched-cards were being used to print from, or if the prints were coming directly from the data.

01101001
2016-Apr-21, 10:32 PM
Read about the program and printed output here: The Big Ear Wow! Signal What We Know and Don't Know About It After 20 Years (http://www.bigear.org/wow20th.htm#printout)

Sounds like the program printed as it ran (and analyzed), in real time and that no punched-card input (from previous data) was used in that process. For each of 50 channels, it printed one symbol, like each character of the famous "6EQUJ5", every 12 seconds, representing average signal strength over a 10-second window, with 2 seconds of analysis.

See About The Wow! Signal (http://www.bigear.org/wowmenu.htm). We've devoted many topics to this subject. It's probably gotten way more attention here than a license plate number deserves.

Superluminal
2016-Apr-22, 07:27 AM
Back to the original question: was it a comet? I'm skeptical, but this star chart from a recent UT article show an interesting coincidence,http://www.universetoday.com/wp-content/uploads/2016/04/Wow-signal-locator.jpg the WOW signal passed right between the comets. Seems a little unlikely that an alien signal would pass directly between two comets. I would like to know how close the comets were to each other? Could their comas have interacted in some way to produce a signal? The comets were at 5 AUs, near the orbit of Jupiter. Where was Jupiter in relation to the comets? Could there have been some reaction between the comets and Jupiter's magnetosphere? If it were an alien signal, I doubt it was an attempt at communication. I think like picking up a far distant AM station at night for a couple of minutes, Big Ear was just looking at the right place at the right time.

publiusr
2016-Apr-30, 08:37 PM
The pigeons were trying to communicate with big ear after all.

"6EQUJ5 = "Quit hosing us out! We have to go to the bathroom somewhere"
The bathroom debate--Next time--on HBO's "Animals"

Or maybe it was just Pigeon from Mike Tyson's mystery team.

01101001
2016-May-01, 12:56 AM
New Jersey pigeon poop was a suspected origin on the Holmdel Horn Antenna (https://en.wikipedia.org/wiki/Holmdel_Horn_Antenna).

The Ohio Big Ear Antenna (http://www.naapo.org/W8JK/Images/BigEar-l.jpg) was more of a huge flat field with giant bed box springs on either end.

Now this doesn't mean birds never hung around the Big Ear -- I'm sure they did -- but the birds of legend were at the Holmdel.

01101001
2016-May-01, 01:14 AM
If it were an alien signal, I doubt it was an attempt at communication. I think like picking up a far distant AM station at night for a couple of minutes, Big Ear was just looking at the right place at the right time.

Seems like if it were an alien signal, it would very likely be an attempt at communication -- but maybe just not meant for us, who just happened to be in the way.

I suppose it could be leakage from alien over-the-horizon radar or similar utilitarian function. But even a radar signal communicates: we are watching. Or, a beacon: we are here.

Ross 54
2016-May-01, 04:16 PM
Back to the original question: was it a comet? I'm skeptical, but this star chart from a recent UT article show an interesting coincidence,http://www.universetoday.com/wp-content/uploads/2016/04/Wow-signal-locator.jpg the WOW signal passed right between the comets. Seems a little unlikely that an alien signal would pass directly between two comets. I would like to know how close the comets were to each other? Could their comas have interacted in some way to produce a signal? The comets were at 5 AUs, near the orbit of Jupiter. Where was Jupiter in relation to the comets? Could there have been some reaction between the comets and Jupiter's magnetosphere? If it were an alien signal, I doubt it was an attempt at communication. I think like picking up a far distant AM station at night for a couple of minutes, Big Ear was just looking at the right place at the right time.

Jupiter was nowhere near the constellation Sagittarius in August, 1977, when the wow signal was received from the direction of that constellation. The ephemeris for that date shows Jupiter to be on the opposite side of the celestial sphere, just about as far away from Sagittarius as possible.

publiusr
2016-May-01, 08:21 PM
New Jersey pigeon poop was a suspected origin on the Holmdel Horn Antenna (https://en.wikipedia.org/wiki/Holmdel_Horn_Antenna).

The Ohio Big Ear Antenna (http://www.naapo.org/W8JK/Images/BigEar-l.jpg) was more of a huge flat field with giant bed box springs on either end.

Now this doesn't mean birds never hung around the Big Ear -- I'm sure they did -- but the birds of legend were at the Holmdel.

Ah! That was their relatives home then...

ShinAce
2016-May-05, 07:29 PM
According to the wiki link DaveC42691 posted above,

(emphasis added)

So it is actually the opposite of my assumption that it would be the naturally noisiest part of the spectrum.

You would expect a lot of noise at a wavelength of 21cm because cold hydrogen is everywhere. However, each hydrogen atom only emits one of these photons every 10 million years or so.

It's everywhere, but very very faint. If you wanted to signal someone who would be mapping hydrogen(like us) in the universe, the 21 cm line is the way to go.

dtilque
2017-Jun-10, 04:33 AM
Seems it's probably comet 266/P Christensen (http://planetary-science.org/wp-content/uploads/2017/06/Paris_WAS_103_02.pdf).

(Sorry, if this was posted before, but a search didn't turn up anything.)

Selfsim
2017-Jun-10, 07:16 AM
Adios ETI!

Superluminal
2017-Jun-10, 07:34 AM
Seems it's probably comet 266/P Christensen (http://planetary-science.org/wp-content/uploads/2017/06/Paris_WAS_103_02.pdf).

(Sorry, if this was posted before, but a search didn't turn up anything.)
"Wow!" That paper does make a convincing case for the "Wow!" signal just being a comet. But, lets keep looking.

slang
2017-Jun-10, 08:24 AM
Last three posts merged into existing thread. There was also a Universe Today story on the same topic (https://forum.cosmoquest.org/showthread.php?160918-%91Wow!%92-Signal-Was%85Wait-For-It%85Comets) that got some posts recently.