Question of the day
- Thread starter spkennyuk
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drewf
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That's some specialist hobby OB!
drewf
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drewf
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Needamaser
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Is the noise something like tectonic plates rubbing together?
Needamaser
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Screams from a drowning fly hit by a nuclear submarine?
Needamaser
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In mph or knots?
daverichardson
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come on drewf
I'm getting bored now
I'm getting bored now
spkennyuk
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In the back of my mind I can remember something about shoals of crayfish clicking their claws during mating season and the sound travelling for miles. The noise is caused by a bubble of air forming in their claws and popping but there are millions of the crayfish doing it at the same time.
Next guess would be tectonic plates shifting past each other.
BennyD
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What the **** would a dray horse be doing that far out in the ocean???
Treading water.
drewf
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spkennyuk has it:
The loudest noise made underwater is made by shrimp. The sound is so loud it will 'blind' the sonar operators on submarines - if they are below the layer of shrimp they can't hear anything above it, and vice versa. This wall of sound is often measured at 246 decibels, which even accounting for the difference in speed of sound in water and air, equates to 160 decibels in air. A jet taking off is around 140...
The noise is caused by trillions of them snapping their single claw simultaneously, but it's not the sound of the claw faces touching which causes the loud sound.
High speed video shows that the sound is generated 700 ms after the claws have closed. The noise actually comes from bursting air bubbles - generated by a process called cavitation. It works like this - the claw is closed so fast that a jet of water is forced out at over 60mph, fast enough to create expanding bubbles of water vapour. When the water slows down and normal pressure is regained, the bubbles collapse, creating intense heat (~20,000 degC), some light (called sonoluminescence) and a loud pop.
As well as ruining sonar, this can actually put dents in ships' propellors.
The loudest noise made underwater is made by shrimp. The sound is so loud it will 'blind' the sonar operators on submarines - if they are below the layer of shrimp they can't hear anything above it, and vice versa. This wall of sound is often measured at 246 decibels, which even accounting for the difference in speed of sound in water and air, equates to 160 decibels in air. A jet taking off is around 140...
The noise is caused by trillions of them snapping their single claw simultaneously, but it's not the sound of the claw faces touching which causes the loud sound.
High speed video shows that the sound is generated 700 ms after the claws have closed. The noise actually comes from bursting air bubbles - generated by a process called cavitation. It works like this - the claw is closed so fast that a jet of water is forced out at over 60mph, fast enough to create expanding bubbles of water vapour. When the water slows down and normal pressure is regained, the bubbles collapse, creating intense heat (~20,000 degC), some light (called sonoluminescence) and a loud pop.
As well as ruining sonar, this can actually put dents in ships' propellors.