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List of Unexplained Sounds (wikipedia.org)
280 points by rsiqueira on June 17, 2012 | hide | past | favorite | 75 comments

SDR (software-defined radio) enthusiasts also found something they can't identify: whistlers. You can see/hear them in this video:


also briefly addressed here:


edit: not on topic, should have refrained from posting as it's a VLF radio phenomenon and not a sound.

Actually, I work in a lab where I'm investigating ELF 'whistlers' that we've detected. It's really interesting stuff - we're not sure what causes them, but we've found some correlation between events and certain limits on the solar elevation angle. We think it might be ions getting trapped and moving along a field line.

Reading back my post I seem to imply that SDR enthusiasts discovered it, that wasn't my intention. This phenomenon was probably well documented before SDR.

When I first saw it, my first thought was "what a strange technique to run a radar, I wonder what the benefit is."

In ELF, would it be possible to set up three omnidirectional antennas and triangulate the source to get an idea in what layer of the atmosphere it's generated? I'd also love to read peer-reviewed publications, please post some references if you can.

I'm not quite sure if it would be possible to triangulate the position of the events - our sensors only detect relative changes in the magnetic field in the X and Y direction. As it stands we have only a handful of sensors: one that we operate at South Pole Station, and data that is made available to us from Taiwan. We are thinking, however, of placing a new sensor at McMurdo station so that we can see how latitude affects our findings.

Something that we've just found in the past few months shows that the occurrence of events can be limited by the elevation of the sun - we've never seen events happen when the sun was below ten degrees elevation at the south pole, and never below thirty degrees in Taiwan. Additionally, events in Taiwan seem to cut out in the two hour period surrounding local noon, suggesting that these might be highly local. They're also somewhat infrequent - we might only find two hundred such events over an entire year. We could go weeks without seeing one, and then get five events within a few hours. This might also suggest that it has something to do with solar heating of the ionosphere, given the timing of events. Note that all of this stuff is new and isn't discussed in any published literature.

As far as what's been published goes, I think there have been maybe half a dozen papers written since this phenomenon was discovered in the seventies. Here are the ones I've been able to quickly grab:

Heacock 1974 - The first report of ELF whistler-like events http://www.agu.org/pubs/crossref/1974/GL001i002p00077.shtml

Sentman 1994 - The second study of ELF whistlers, and the only study of mid-latitude events http://www.agu.org/pubs/crossref/1994/93JA02103.shtml

Wang 2005 - First report of ELF whistlers in Taiwan http://www.agu.org/pubs/crossref/2005/2005GL022412.shtml

Kim 2006 - First reports of the events at the south pole http://www.agu.org/pubs/crossref/2006/2005GL023638.shtml

Wang 2011 - Reports on new events detected in Taiwan http://www.agu.org/pubs/crossref/2011/2011JA016832.shtml


It belongs in the same category "unidentified signals". I for one find it pretty interesting.

There really should be a warning at the start of those videos telling you to turn the volume down.

This may be a bit off topic, but when I get into looking at this type of (mysterious, interesting) of Wikipedia article, I usually end up back at my favorite of the category:


Best quote ever: 'In his most recent writings, Ehman resists "drawing vast conclusions from half-vast data"'.

"Also, the 1420 MHz signal is problematic in itself in that it is "protected spectrum": it is bandwidth in which terrestrial transmitters are forbidden to transmit due to it being reserved for astronomical purposes."

Wait... what?? If this has been enforced on Earth, then clearly other civilizations might make the same choice and not broadcast anything on that frequency.

Does anyone know if we are broadcasting anything into space on this frequency?

This frequency is protected because there is a gap in the absorption spectrum of our atmosphere. This is not the same for every atmosphere, so other planets will have different gaps (unless the composition of gases is similar enough), and thus it won't make too much sense right now to single out this frequency for other civilisations. AFAIK we don't broadcast, because it would interfere with astronomic measurements.

Not true. While some of the radio spectrum has been reserved specifically because of the lack of absorption in the atmosphere, the 1420MHz line is the famous 21cm line frequenctly measured by cosmologists to look at the epoch of reionization. It is due to the hyperfine structure of hydrogen, and would not be of unique importance to our civilization.

However, we don't broadcast anything. Any broadcasts from earth would hugely overshadow any small signal we're trying to read.

Ups, thanks for the correction.

I lived in Taos, NM for about a year and never heard the eponymous Hum. Recalling the recent Hacker News item about anechoic chambers, it wouldn't surprise me if it has something to do with how quiet the place is.

On more than one occasion standing outside the house on the mesa outside of town, the utter silence of the place got to me enough that I had to go back inside and talk to somebody. Perhaps my mind would have eventually filled the gap with a hum.

This is unrelated but your comment made me think of it and you may find it interesting.

At age 13 I moved from San Diego CA to Brooklyn Park MN. Shortly after the move I spent a summer helping my stepfather's grandfather build an addition on his house. He lived in Park Rapids MN which in a very isolated, rural area 4 hours north of Minneapolis. After the first few weeks there I started to feel like I was going crazy. I had no history of mental illness but I was suddenly feeling increasingly anxious and agitated with each new day...then I put a hat on.

After I put on the hat, I felt normal again. I had always lived in cities and never had an unobstructed view for more than a mile or so. Out in the country I could see for many miles and it had an effect on me. The bill of the hat blocked my view.


Or it is there (and maybe everywhere) but we can't hear it

One thing that's noticeable when it's really quiet (and having lived in a place where it is silent at night) is that the threshold of hearing changes a lot. Something that's barely audible in normal conditions can "scream" at night

Example: the sound of soda fizzing in your mouth.

If it's really, really quiet you can hear yourself blink!

Maybe that's why we keep our eyes closed while we sleep.

Always sounds like http://ia600500.us.archive.org/12/items/ird059/tcp_d1_01_the...

(give it some time...)

and http://www.lostcosmonauts.com/firstman.ra managed to scare the hell out of me...


I wonder how fear and sounds like these are wired in our brains...

I've heard of the lost cosmonauts before. But what is the first sound? I haven't listened to all of it yet, mainly because you grouped it with the lost cosmonauts, and those recordings scare the hell out of me as well, even though I believe they are mostly hoaxes.

It's certainly not hard to guess why unknown sounds would trigger fear in humans from an evolutionary standpoint. Biologically I wouldn't care to speculate.

The first sound is a (german) numbers station where a woman (i can't help my self and interpret the voice as a child's voice) speaks some testing numbers (i guess) it's 1,2,3,4,5,6,7,8,9,0 - the interleave signal is: http://en.wikipedia.org/wiki/Swedish_Rhapsody_No._1

Sorry for asking, but what is odd about this sound? I also don't know what a interleave is.

But, anyway, this sounded to me as something we could find in a station from Lost.

These real life mysteries were probably part of the inspiration for Lost.


Everyone loves numbers stations. Here's a video of one of the actual devices used to generate those signals: http://www.youtube.com/watch?v=Xkc_Ig87TnM

Besides being a number station, I'm not sure there's anything particularly strange about that recording.

These could be the underwater equivalent of the sound of wind in a cave.

Powered by volcanic emissions instead of wind. Depending on the shape of the orifice and the size/shape of the chamber, it could make any kind of sound.

I was thinking of filtering of the random noise by features in the environment as well - perhaps thermal gradients in the water setting up reflections &c.

It's never aliens. It always turns out to be a prank, or ice cracking, or some other boring natural cause. Why can't it be aliens!?

A loose association of alien races scattered across the galaxy, called The Pranksters by their victims and eventual associates.

If it ever is aliens, I hope they aren't some boring little bugs. They need to be just like in the movies.

Acid blood would be great too!

Like in Howard the Duck?

Interesting that most of them are detected in 1997 (4 out of 6 specific ones).

Also, by the same thing: Equatorial Pacific Ocean autonomous hydrophone array.

I can't find much about it after ten seconds' worth of googling, but maybe that's when it was constructed?

Looks like it:

"In May, 1996 the array was successfully deployed in the eastern equatorial Pacific to begin long-term monitoring of the East Pacific Rise between 20N and 20S."


"The train" gives me the chills

The worst for me was Julia. It sounds like muttering.

It's 1AM here, I don't think I'm gonna play it. :)

Same timezone as you then, I actually find them cool :P Some give me chills as well.

Upsweep is even worse man

Reminiscent a little of this: http://www.youtube.com/watch?v=bQf8Mns_sK8

I mean, how much more evidence do you need to see Lovecraft was spot on: Discovery of mysterious Antarctic mountains under ice, just as he described; mysterious sounds near the resting place of Cthulhu; what will be next, I wonder?

In large bodies of water, do you not observe oscillating sounds? I can't explain it very well (I forget the official name) but it's like pushing a wave onto another wave at just the right frequency so it creates a huge wave, could the same thing not happen with sounds in water? It might explain the ones that build up and then gradually decrease. I don't know much about this and am probably wrong but it's something I've always wondered.

If you had enough random sounds going off in the water, given enough time some would group up together I imagine to create freak sound waves.

The effect is called superposition: http://en.wikipedia.org/wiki/Superposition_principle

Something like this: http://en.wikipedia.org/wiki/Seiche ?

I live in Calgary, AB and used to hear something similar to the Hum approximately 4 years ago. At the time I was in a basement suite and would occasionally wake up and would hear a humming noise (unsure if I was waking due to the hum or not.) Eventually, the conclusion that I came to was that because I was "underground" the low frequency of a train yard not far from my house was the cause of the noise.

My wife frequently tells me that I have sensitive ears. And I've had to leave rooms because of feedback in a sound system that no one seems to be able to hear.

"The Hum" [1] is the most interesting to me, because my dad claims he used to hear the exact same kind of sound -- like a diesel engine starting up -- in the mornings when he lived in an older house with my mother.

[1]: http://en.wikipedia.org/wiki/The_Hum

I'm German currently in Canada and I heard the Hum apparently quite often in the last few days, never in Germany though. I've been on a very remote ranch somewhere 3 hours from Kamloops, BC and at first, I thought it was indeed a diesel engine starting up. Thing is, there was no neighbor close to that huge property. Then I heard it also 500m further away, same noise, same volume and also the same pattern. It's just for a short moment, 3-5 single tones in a row.

Then I drove with an ATV to some lake in the middle of nowhere and heard it again. I asked the other person I was with and she just said "well, it's someone starting a diesel engine". And I thought again: Who does start a diesel engine in the middle of nowhere. I thought it might be an animal or so, but could never tell for sure.

Edit: The interesting aspect is that I heard the Hum probably 3-4 times. 2x I was alone and in both other occasions, two different people heard the same sound. So I guess it was not just in my ears.

This is directed at the parent and grandparent.

Could it be a grouse?

Your descriptions of a 'diesel engine starting' are different than the description in the wiki article of a diesel engine running. A running diesel engine would make a droning hum, while a starting one would click or tick and thump faster and faster into a hum.

That start-up noise is very similar to the sound of a grouse, a common bird in rural areas. A friend and I were hiking for a few days a few years ago, and we felt completely isolated and hadn't heard human noise for days... except that someone kept starting an engine a few hundred yards away! We knew it must not be people, but were baffled.

When we finally got back we asked his family members if they knew the source of those noises, and they showed us a youtube clip about grouse. Surprisingly noisy little things. I would seek a video for you, but I am on a restrictive telephone.

Oh yeah, funny, that's probably it. I think I've even seen one of them somewhere in the bush. Thanks for clarification :)

Well, but isn't starting a diesel engine something to be expected in rural Canada?

I mean, generators, trucks, etc?

Now see, in distances, it appears that lower frequency sound waves travel better. For example, take someone that's hearing music far away from you, the higher frequencies sound distinctively dampened.

So I wouldn't be surprised if a diesel engine could be heard a very long distance away in a quiet region

BBC Documentary about The Hum: (with Bill Bailey)


At first I was like "Well, animals, obviously", but now I'm not so sure...

Indeed. There was some speculation in one of the articles that it may have been big ice sheets sliding along rock that was making those subsonic noises.

Here is what Jupiter sounds like, (electromagnetically):


Recommended: http://www.discogs.com/No-Artist-Symphonies-Of-The-Planets/r...

(An excellent sleep soundtrack)

I remember reading a wikipedia article on the Bloop about half a year ago, and none of these other unexplained sounds were on it. Seems like NOAA fanboys dug up and wrote the others.

That being said NOAA fanboys are far more preferable to Apple fanboys. :)

I don't understand this.

What, is there an archive out there that has every recorded sound by every single human being and along with has complete information about the recording, and only these 7 clips are not understood?

> This list is incomplete; you can help by expanding it.

it goes the other way (grouping of things, rather than subsetting):

1. X sound is found and nobody understands what causes it

2. X gets a wikipedia page

3. someone creates a list of various pages such as X

4. optional, some other people add more pages such as X having noticed the list

Partly - the specific ones all seem NOAA originated, which iirr is the American oceanographer group. They along with Navy proper have very vested interests in identifing unusual ocean sounds. But just as you can find parrots that say good morning, given enough fish swimming past enough deep seamicrophones, eventually one ofthem will sound like they are whistling a braoadway tune

sorry folks, fun, creepy but in the end self selecting and probably in the strange things happen on the planet category.

The sounds are extremely loud and some of them are recurring. Impossible for a fish to cause something like that. The explanation is probably quite prosaic, like ice creeping over Antartica, yet the sounds do carry some significance.

Even if it is a natural phenomenon, am I alone in thinking that it is still interesting?

Absolutely not. I think a lot of people are intrigued by this.

"Skeptical thinking" at its best

I'm really hoping you are a troll, because otherwise you're in "youtube commenter" category of intelligence

"eventually one ofthem will sound like they are whistling a braoadway tune""

Yes, please explain how a school of fish can create a sound with that power and spectrum, because you obviously know so much about mathematical wave properties and the laws of conservation of energy.

"NOAA originated, which iirr is the American oceanographer group""

Yes, and NASA works with planes and stuff

I do hate it when someone on the Internet thinks I am a troll.

Firstly, yes I am sure I should have phrased my position better. So lets try that

- If you listen to hundreds of hydrophones over hundreds of hours, and hear only a handful of unexplained sounds, and promote only half a dozen, it is unlikely what you promote is of scientific interest. It may be interesting but not of interest.

And thats it. NOAA has done no more then say some of its findings it cannot explain ... and then self-selected a few that sound a bit weird.

This does not make them important, relevant, repeatable, or admitting of no explanation whatsoever. Just not explained now. And later they could explain some (Upsweep being a volcano that was thought extinct)

And 'we' then anthropomorphize. Can we hear the word Julia? No we cannot. (go listen to the TED talk below - last 3 minutes)

I recognise there are many things in a deep ocean we have not seen or discovered (I liked Bill Brysons analogy that we had explored the Oceans depths as if we explored Central Park using 5 guys on tractors, at night with torches). But weird sounds that you have to squint at to find meaning in. Squarely in the Skeptical category of for me publication bias and anchoring.

I am unclear what is a mathematical wave property, but I am clear that it is reasonable to use fish singing broadway melodies as a stand-in for unusual events underneath the ocean waves. I was not suggesting that to be a literal explanation. (Even though it would be a good one to hear)

Oceanographer comment:

(NOAA- Yes, Oceanographers - measuring and mapping the ocean - with 3bn of their 5bn budget aimed at satellites, weather monitoring and plain old research, I am happy to categorise them as Oceanographers. Yes they do other important stuff too. But mostly they monitor the water/air co-systems on the planet.


http://www.whaletrust.org/whales/whale_song.shtml http://www.noaa.gov/budget/ http://asia.cnn.com/2002/TECH/science/06/13/bloop/index.html

RIght -waaaay too long on a rebuttal that frankly is not detailed enough and will get flamed if anyone bothers reading it. Work now.

"- If you listen to hundreds of hydrophones over hundreds of hours, and hear only a handful of unexplained sounds, and promote only half a dozen, it is unlikely what you promote is of scientific interest. It may be interesting but not of interest."

The keyword here is "in tandem". Sure, in one hydrophone you'll hear a pebble dropping, in another, a fish drowning, but this is not it.

This is a loud sound, heard by an entire array of microphones simultaneously, pinpointed at 5000km away (or around 3100mi). (See http://en.wikipedia.org/wiki/Bloop )

"I am unclear what is a mathematical wave property, but I am clear that it is reasonable to use fish singing broadway melodies as a stand-in for unusual events underneath the ocean wave"

What I meant to say is that NOAA and others have looked at the sound spectrum (and power) and no good explanation has been found, but a "giant whale" (or a choir of fish) is as believable as "aliens".A crowd of people is loud, but an uncoordinated event only goes so far. Other known geological phenomena like ice falling apart have been ruled out more or less.

It's not promoted because "it's funny", it's promoted because there are not a good explanation for such events, and it's something scientifically significant (something that can be heard from 3000mi away is really loud)

"NOAA- Yes, Oceanographer" sure they are, but the comment doesn't do them justice. They are Oceanographers yes, but it's a little bit condescending given the work they do. Like saying the DOE makes your toaster work.

I understand the list but I don't know how this stuff gets frontpaged so often in so many places. "Bloop"


Wow. Maybe it was the loch ness monster on vacation. Or maybe...a bubble. I mean, come on.

The sample is at 16x the original speed. And was heard over 5000km. In other words, not a bubble. Or if it was, it was a bubble worthy of its own wiki page.

Yeah, ok. It could have been wonderful, tremendous things. IE, lochy. But I've seen this on front pages at least 50 times and there has not been the tiniest insight into what that is beyond nothing at all. Occam's razor: It was a bubble, an electrical malfunction, a manufactured hoax, etc. Why don't you post a shaky video of bigfoot instead? At least the imagination has something to chew on there.

Occam's Razor isn't "jump to simple conclusions" or "don't bother thinking about it".

It's a rule of thumb stating that you should pick the simplest of two equivalent explanations. In this case there aren't even any proposed explanations, so it does not even apply.

Or it could be something actually real and interesting like the shrimp layer http://www.youtube.com/watch?v=tkgJQ1Fpwm4#t=1140s

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