View source for Unsolved:List of unexplained sounds

{{short description|Wikimedia list article}}
The following is a '''list of unidentified, or formerly unidentified, sounds'''. All of the sound files in this article have been sped up by at least a factor of 16 to increase intelligibility by condensing them and raising the frequency from [[Physics:Infrasound|infrasound]] to a more audible and reproducible range.

==NOAA (unidentified)==

The following unidentified sounds have been detected by the U.S. [[Organization:National Oceanic and Atmospheric Administration|National Oceanic and Atmospheric Administration]] (NOAA) using its Equatorial Pacific Ocean autonomous hydrophone array.

=== Upsweep ===

[[File:Upsweep Espectrograma.jpg|thumb|left|150px|alt=Spectrogram of the Upsweep sound|Spectrogram of the ''Upsweep'' sound]]
{{Listen
 |filename     = Upsweep 20×.ogg
 |title        = Upsweep
 |description  = Upsweep, from the NOAA website at 20x the original speed.}}
'''Upsweep''' is an unidentified sound detected on the American NOAA's equatorial autonomous hydrophone arrays. This sound was present when the [[Organization:Pacific Marine Environmental Laboratory|Pacific Marine Environmental Laboratory]] began recording its sound surveillance system, [[Earth:SOSUS|SOSUS]], in August 1991. It consists of a long train of narrow-band upsweeping sounds of several seconds in duration each. The source level is high enough to be recorded throughout the Pacific.

The sound appears to be seasonal, generally reaching peaks in spring and autumn, but it is unclear whether this is due to changes in the source or seasonal changes in the propagation environment. The source can be roughly located at {{Coord|54|S|140|W|dim:5000000}}, between New Zealand and South America. Scientists/researchers of NOAA speculate the sound to be underwater volcanic activity. The Upsweep's level of sound (volume) has been declining since 1991, but it can still be detected on NOAA's  equatorial autonomous hydrophone arrays.<ref name="noaa1">{{cite web|url=http://www.pmel.noaa.gov/vents/acoustics/sounds/upsweep.html|title=Upsweep|publisher=[[Organization:National Oceanic and Atmospheric Administration|National Oceanic and Atmospheric Administration]]|access-date=2011-08-20}}</ref>

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=== Whistle ===
[[File:Whistle (spectrogram).jpg|thumb|left|150px|alt=Spectrogram of the ''Whistle sound|Spectrogram of the ''Whistle sound]]
{{Listen
 |filename     = Whistle 16×.ogg
 |title        = Whistle 
 |description  = The Whistle, from the NOAA website at 16x the original speed.
}}
This mysterious sound, dubbed the Whistle, was picked up by one NOAA hydrophone in 1997. The location of this sound is unknown, and the source is somewhere in the Pacific Ocean. According to NOAA, the '''Whistle''' is similar to [[Earth:Submarine volcano|volcanogenic]] sounds previously recorded in the Mariana [[Earth:Volcanic arc|volcanic arc]] of the [[Earth:Pacific Ocean|Pacific Ocean]], but since it was only recorded on one hydrophone rather than the three required to triangulate a location, it is considered "unidentified".<ref name="noaa2">{{cite web|url=http://www.pmel.noaa.gov/vents/acoustics/sounds/whistle.html|title=Whistle|publisher=[[Organization:National Oceanic and Atmospheric Administration|National Oceanic and Atmospheric Administration]]|access-date=2011-08-20}}</ref>
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== NOAA (formerly unidentified) ==

=== Bloop ===
[[File:Bloop.jpg|150px|thumb|left|A [[Spectrogram|spectrogram]] of Bloop]]

'''[[Earth:Bloop|Bloop]]''' is the name given to an ultra-low-frequency and extremely powerful underwater sound detected by the U.S. [[Organization:National Oceanic and Atmospheric Administration|National Oceanic and Atmospheric Administration]] (NOAA) in 1997.  The sound is consistent with the noises generated by icequakes in large icebergs, or large icebergs scraping the ocean floor.<ref name=pmel1 />

==== Analysis ====

The sound's source was roughly triangulated to a remote point in the south Pacific Ocean west of the southern tip of South America, and the sound was detected several times by the Equatorial Pacific Ocean autonomous hydrophone array.<ref name=pmel1>{{cite web|url= http://www.pmel.noaa.gov/vents/acoustics/sounds/bloop.html |title=Acoustics Monitoring Program - Icequakes (Bloop) |work=Pacific Marine Environment Laboratory |publisher=NOAA.gov |access-date= 2012-11-17}}</ref> 
{{Listen|filename = Bloop real.ogg|title= Bloop|description  = Bloop at 16x the original speed, from the NOAA website.}}

According to the NOAA description, it "rises rapidly in frequency over about one minute and was of sufficient amplitude to be heard on multiple sensors, at a range of over {{convert|5,000|km|mi|abbr=on}}." The NOAA's Dr. Christopher Fox did not believe its origin was man-made, such as a submarine or bomb, nor familiar geological events such as volcanoes or earthquakes. While the audio profile of Bloop does resemble that of a living creature,<ref>{{cite web|url=http://www.science.org.au/nova/newscientist/102ns_001.htm |title=Calls from the deep |work=New Scientist |first=David |last=Wolman |date=2002-06-15 |access-date=2012-01-16 |url-status=dead |archive-url=https://web.archive.org/web/20130106141048/http://www.science.org.au/nova/newscientist/102ns_001.htm |archive-date=2013-01-06 }}</ref> the source was a mystery both because it was different from known sounds and because it was several times louder than the loudest recorded animal, the [[Biology:Blue whale|blue whale]].<ref>{{cite web |url= http://nationalzoo.si.edu/Animals/AnimalRecords/default.cfm |title= Animal Records |publisher= Smithsonian National Zoological Park |access-date= 2010-09-26 |archive-url= https://web.archive.org/web/20100305074229/http://nationalzoo.si.edu/Animals/AnimalRecords/default.cfm# |archive-date= 2010-03-05 |url-status= dead }}</ref>

The NOAA Vents Program has attributed Bloop to a large [[Earth:Cryoseism|icequake]]. Numerous icequakes share similar spectrograms with Bloop, as well as the amplitude necessary to spot them despite ranges exceeding {{convert|5000|km|mi|abbr=on}}. This was found during the tracking of iceberg A53a as it disintegrated near South Georgia Island in early 2008. If this is indeed the origin of Bloop, the iceberg(s) involved in generating the sound were most likely between Bransfield Straits and the Ross Sea, or possibly at Cape Adare in Antarctica, a well-known source of [[Physics:Cryogenics|cryogenic]] signals.<ref name=pmel1 />



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=== Julia ===
[[Image:Julia-unidentified-sound-spectrogram.jpg|150px|thumb|left|A [[Spectrogram|spectrogram]] of "Julia".]]
{{Listen|filename = Julia sound.ogg|title = Julia|description = Julia sound, from the NOAA website at 16x the original speed.}}
'''Julia''' is a sound recorded on March 1, 1999, by the U.S. [[Organization:National Oceanic and Atmospheric Administration|National Oceanic and Atmospheric Administration]] (NOAA). NOAA said the source of the sound was most likely a large iceberg that had run aground off Antarctica.  It was loud enough to be heard over the entire [[Earth:SOSUS|Equatorial Pacific Ocean autonomous hydrophone array]], with a duration of about 2 minutes and 43 seconds. Due to the uncertainty of the arrival [[Azimuth|azimuth]], the point of origin is most likely located near the equator by South America, in the Pacific Ocean. Location (15°S 98°W)<ref name="noaa3">{{cite web|url=http://www.pmel.noaa.gov/vents/acoustics/sounds/julia.html |title=Acoustics Monitoring Program |publisher=pmel.noaa.gov |date=1999-03-01 |access-date=2012-11-12}}</ref>

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=== Slow Down ===
[[Image:Slow Down.jpg|thumb|left|150px|The [[Spectrogram|spectrogram]] of Slow Down]]
{{listen|title="Slow Down", at 16 times its original speed.|filename=Slowdown.ogg}}
'''Slow Down''' is a sound recorded on May 19, 1997, in the Equatorial [[Earth:Pacific Ocean|Pacific Ocean]] by the U.S. [[Organization:National Oceanic and Atmospheric Administration|National Oceanic and Atmospheric Administration]]. The source of the sound was most likely a large iceberg as it became grounded.<ref name="noaa5">[http://www.pmel.noaa.gov/acoustics/sounds_cryogenic.html NOAA Cryogenic "Slow Down"]</ref>

==== Analysis ====

The name was given because the sound slowly decreases in [[Physics:Frequency|frequency]] over about seven minutes. It was recorded using an autonomous hydrophone array.<ref name="noaa4">[http://www.pmel.noaa.gov/vents/acoustics/sounds/noise97139.html NOAA page]</ref> The sound has been picked up several times each year since 1997.<ref name="New Scientist">{{cite web|url=http://www.science.org.au/nova/newscientist/102ns_001.htm |archive-date=6 January 2013 |archive-url=https://web.archive.org/web/20130106141048/http://www.science.org.au/nova/newscientist/102ns_001.htm |title=Calls from the deep |date=15 June 2002 |author=David Wolman |page=35 |issue=2347 |journal=New Scientist |url-status=dead }}</ref> One of the hypotheses on the origin of the sound is moving ice in Antarctica. Sound spectrograms of vibrations caused by friction closely resemble the spectrogram of the Slow Down. This suggests the source of the sound could have been caused by the friction of a large ice sheet moving over land.<ref name="New Scientist" />

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=== Train ===
[[File:Train Spectrogram.jpg|thumb|left|150px|alt=Spectrogram of the ''train'' sound|Spectrogram of the ''train'' sound]]
The '''Train''' is the name given to a sound recorded on March 5, 1997, on the Equatorial Pacific Ocean autonomous hydrophone array. The sound rises to a quasi-steady frequency. According to the NOAA, the origin of the sound is most likely generated by a very large iceberg grounded in the Ross Sea, near Cape Adare.<ref>{{cite web|title=Iceberg Grounding (Train)|url=http://www.pmel.noaa.gov/vents/acoustics/sounds/train.html|publisher=NOAA|access-date=24 October 2012}}</ref>
{{Listen
 |filename     = Train (unidentified sound).ogg
 |title        = Train
 |description  = The Train, from the NOAA website at 16x the original speed.}}

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==Other==
* Sounds produced by the Northern Colossus of Memnon following an earthquake in 27 BC; the noises made by the statue were probably caused by rising temperatures and the evaporation of dew inside the porous rock of the statue.<ref name="colossi of mnemon">{{cite book | title=The Voice of Mnemon - Tales of Travel | author=Lord Curzon | year=1923}}</ref> 
* Unusual noises heard near One World Trade Center, attributed to wind moving through and around the unfinished building. Strange 'wailing' noises were reported during the transit of Hurricane Sandy, while the building was still under construction.<ref>[http://www.huffingtonpost.com/2013/12/03/one-world-trade-center-noises_n_4377498.html One World Trade Center Makes Strange, Ghostly Sounds In Lower Manhattan (VIDEOS)], ''Huffington Post''</ref>
* [[Biology:Bio-duck|Bio-duck]], a sound that is produced by the [[Biology:Antarctic minke whale|Antarctic minke whale]].<ref name=Rischetal>{{Cite journal
 | doi = 10.1098/rsbl.2014.0175
| title = Mysterious bio-duck sound attributed to the Antarctic minke whale (''Balaenoptera bonaerensis'')
| journal = Biology Letters
| volume = 10
| issue = 4
| pages = 20140175
| year = 2014
| last1 = Risch | first1 = D.
| last2 = Gales | first2 = N. J.
| last3 = Gedamke | first3 = J.
| last4 = Kindermann | first4 = L.
| last5 = Nowacek | first5 = D. P.
| last6 = Read | first6 = A. J.
| last7 = Siebert | first7 = U.
| last8 = Van Opzeeland | first8 = I. C.
| last9 = Van Parijs | first9 = S. M.
| last10 = Friedlaender | first10 = A. S. | pmid=24759372 | pmc=4013705
}}</ref><ref>{{Cite report
 |author1=Rob McCauley |author2=John Bannister |author3=Chris Burton |author4=Curt Jenner |author5=Susan Rennie |author6=Chandra Salgado Kent |date=October 2004
 | title      = Western Australian Exercise Area Blue Whale Project, Final Summary Report, Milestone 6
 | url        = http://www.cwr.org.au/wp-content/uploads/waxa2004.pdf 
 | publisher  = Australian Defence
 | access-date = 2012-06-26
 | quote = A signal type widely heard by Navy submariners and known as the bioduck is common in the [Perth] Canyon during late July-Dec [1999-2004]. The seasonal timing of the bioduck is similar to other great whales which migrate up from Antarctic waters.
}}</ref>

* The Ping, described as "acoustic anomalies" whose "sound[s] scare sea animals". It is heard in the Fury and Hecla Strait of northern Canada. It is being investigated by Canadian military authorities.<ref>[http://www.upi.com/Odd_News/2016/11/05/Canadian-military-investigating-mysterious-ping-sound-scaring-sea-animals/1851478367910/ Canadian military investigating mysterious 'ping' sound scaring sea animals]</ref> 
* The Forest Grove Sound, a sound heard in Forest Grove, Oregon during February 2016.<ref>{{Cite news|url=http://www.kgw.com/news/local/forest-grove-neighbors-mystified-by-annoying-noise/45296369|title=Forest Grove Neighbors Mystified by Annoying Noise|last=Cook|first=Katherine|date=25 February 2016|work=KGW|access-date=5 January 2017}}</ref>
* Moodus noises, strange sounds heard in Moodus, Connecticut, later attributed to microquakes.

==Non-specific==
* [[Physics:The Hum|The Hum]]
* Mistpouffers or [[Earth:Skyquake|Skyquake]]s, a phenomenon generally occurring near large bodies of water. Sound has been compared to distant cannonfire or thunder.
* [[Unsolved:Havana syndrome|Havana syndrome]], grating noises of unknown origin purportedly heard by United States and Canadian embassy staff in [[Place:Havana|Havana]], Cuba.

== See also ==
*[[Physics:52-hertz whale|52-hertz whale]]
*Numbers station
*[[Medicine:Tinnitus|Tinnitus]]
*UVB-76

== Notes ==
{{notelist}}

=== References ===
{{Reflist|30em}}

[[Category:Unexplained phenomena| ]]

{{Sourceattribution|List of unexplained sounds|1}}