The Bloop - an unidentified, ultra-low frequency sound

[Rocket254]

Anyone heard/know it?

If so, what is your opinion? Real?

[Ivan Seeking]

The Bloop is the name given to an ultra-low frequency underwater sound detected by the U.S. National Oceanic and Atmospheric Administration several times during the summer of 1997. The source of the sound remains unknown. [continued]
http://en.wikipedia.org/wiki/Bloop

It appears to be on the level.
http://oceanexplorer.noaa.gov/explorations/sound01/background/seasounds/seasounds.html#Anchor-1515

Thanks. I had never heard of this before. :smile:

[Rocket254]

No problem. I stumbled upon it while looking up info on the "Cloverfield" movie.

Pretty interesting.

[Mech_Engineer]

One of the greatest websites ever to grace the internet has an article on it:

http://www.damninteresting.com/?p=517#more-517

[Ivan Seeking]

This has been added to our list of credible anomalies.
http://www.physicsforums.com/showthread.php?t=58374

[glondor]

There are recordings of "the bloop" here.
http://www.bloopwatch.org/thebloop.html

[lisab]

Sounds like a whale passing gas.

[Moonbear]

I'm trying to figure out why the NOAA website has speeded up the recording so much. It would make it very hard to identify anything. Then, the recording on the Wikipedia site seems to have been slowed down from the sped up version...not sure what is lost in that process.

Listening to the version on the NOAA website, it's impossible to tell much. The version on the Wiki site, which I'm not sure if it's an old version of the file before it was sped up, or if it's a slowed down version of the 16X recording on the NOAA site, sounds to me like there's more than one "voice." It seems to start out as a "solo" and then shortly, it seems like it jumps in volume and complexity as if another "voice" has joined, and then gets even louder like multiple "voices" are jumping in.

From the biological organism hypothesis, this makes sense if it's a pod of whales or something like that all joining in vocalizing, perhaps mating or feeding or alerting to predators.

I wonder how they determined the origin of the sound. For the sound to have traveled all the way from 50 degrees S to be audible on detectors near the equator is really impressive if that's some sort of sea creature vocalizing over that range.

[RonL]

I'm curious how they can be so certain that it was not just some type of sound made by plate movement, or a subterranean cavern collapse?

[LtStorm]

I wonder how they determined the origin of the sound. For the sound to have traveled all the way from 50 degrees S to be audible on detectors near the equator is really impressive if that's some sort of sea creature vocalizing over that range.

I'd guess they triangulated its origin based on the data they received from more than one of the hydrophones that picked it up. Though I don't think they were *very* specific either, just giving latitude and longitude.

I'm curious how they can be so certain that it was not just some type of sound made by plate movement, or a subterranean cavern collapse?

The article in Damn Interesting noted it fit the profile of a biologically created call. I don't know exactly how that'd be determined, maybe using an algorithm to evaluate the waveform?

[matthyaouw]

I'm curious how they can be so certain that it was not just some type of sound made by plate movement, or a subterranean cavern collapse?

Earthquakes and underwater landslides etc are fairly common (think tsunami). As such there are probably a great many recorded events to compare it to. If it doesn't fit the sounds made by most of those then it's not unreasonable to think it might be something different. By knowing the epicentres of earthquakes and the speed of sound in water it'd be pretty easy to find a matching event- I wonder if this has been looked in to.

[glondor]

I would be curious as to what all the submarine navys of the world have recorded with their millions of hours of undersea listening. I am sure all recordings of an undetermined nature are classified. I think there is more in the sea than we are aware of at this time.

[DaveC426913]

I'm curious how they can be so certain that it was not just some type of sound made by plate movement, or a subterranean cavern collapse?


[Scientist Christopher Fox of the U.S. National Oceanic and Atmospheric Administration's Acoustic Monitoring Project at Portland, Oregon] says:

"The sound waves are almost like voice prints. You're able to look at the characteristics of the sound and say: 'There's a blue whale, there's a fin whale, there's a boat, there's a humpback whale and here comes and earchquake,"

http://archives.cnn.com/2002/TECH/science/06/13/bloop/