

List of Unexplained Sounds - rsiqueira
http://en.wikipedia.org/wiki/List_of_unexplained_sounds

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

<http://www.youtube.com/watch?v=0Hv--BR0ddE>

also briefly addressed here:

<http://www.youtube.com/watch?v=ZuRcaxpbYCw>

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

~~~
el_zorro
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.

~~~
toemetoch
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.

~~~
el_zorro
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>

~~~
toemetoch
Thanks!

------
patdennis
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:

<http://en.wikipedia.org/wiki/Wow!_signal>

~~~
evolve2k
Best quote ever: 'In his most recent writings, Ehman resists "drawing vast
conclusions from half-vast data"'.

~~~
martinkallstrom
"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?

~~~
kaybe
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.

~~~
harshpotatoes
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.

~~~
kaybe
Ups, thanks for the correction.

------
ANH
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.

~~~
raverbashing
Maybe

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.

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

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

------
dlsym
Always sounds like
[http://ia600500.us.archive.org/12/items/ird059/tcp_d1_01_the...](http://ia600500.us.archive.org/12/items/ird059/tcp_d1_01_the_swedish_rhapsody_irdial.mp3)

(give it some time...)

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

 _shiver_

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

~~~
rquantz
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.

~~~
dlsym
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>

~~~
dudurocha
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.

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

<http://en.wikipedia.org/wiki/Numbers_station>

------
ars
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.

~~~
keithpeter
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.

------
ryanwaggoner
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!?

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

~~~
purchas
Acid blood would be great too!

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

~~~
pavel_lishin
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?

~~~
KC8ZKF
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."

<http://www.pmel.noaa.gov/vents/acoustics/haru_system.html>

------
tintin
Reminds me of the sound of ice. Some examples:

<http://www.youtube.com/watch?v=wd-94VvaT0Q>

<http://www.youtube.com/watch?v=8VbyyhCscVc>

------
adaline
"The train" gives me the chills

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

~~~
lucb1e
Same timezone as you then, I actually find them cool :P Some give me chills as
well.

------
Jun8
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?

------
TomGullen
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.

~~~
stu_k
The effect is called superposition:
<http://en.wikipedia.org/wiki/Superposition_principle>

------
gavingmiller
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.

------
mintplant
"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>

~~~
WA
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.

~~~
wcarss
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.

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

------
nilaykumar
<http://www.science.org.au/nova/newscientist/102ns_001.htm>

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

~~~
huwr
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.

------
maeon3
Here is what Jupiter sounds like, (electromagnetically):

<http://www.youtube.com/watch?v=e3fqE01YYWs>

~~~
dzuc
Recommended: [http://www.discogs.com/No-Artist-Symphonies-Of-The-
Planets/r...](http://www.discogs.com/No-Artist-Symphonies-Of-The-
Planets/release/631223)

(An excellent sleep soundtrack)

------
anaheim
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. :)

------
hasenj
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?

~~~
lifeisstillgood
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.

~~~
kmm
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.

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

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

