Can you break the sound barrier under water?

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Discussion Overview

The discussion revolves around the concept of breaking the sound barrier in water, exploring the implications of sound propagation in different mediums, and the feasibility of underwater objects exceeding the speed of sound. Participants also touch on related topics such as sound in space and the nature of sound waves.

Discussion Character

  • Exploratory
  • Debate/contested
  • Technical explanation

Main Points Raised

  • Some participants assert that there is no sound barrier in space, as sound requires a medium to propagate.
  • In fresh water at 20°C, the speed of sound is approximately 1482 m/s, which is significantly higher than in air.
  • One participant proposes that while an object can theoretically travel faster than sound in water, it would create cavitation, effectively altering the medium's state around it.
  • There is speculation about the existence of supersonic torpedoes developed by military forces, with one participant suggesting that these may utilize bubbles to reduce water resistance.
  • Another participant questions the feasibility of hearing sounds from the sun, leading to humorous exchanges about the practicality of such an endeavor.
  • Some participants discuss the implications of underwater objects, such as meteors or hypothetical submarines, achieving speeds greater than sound.
  • There are references to the Shkval torpedo, which reportedly uses a bubble film to achieve high speeds underwater.

Areas of Agreement / Disagreement

Participants express differing views on the nature of sound propagation in water versus air, the existence of sound barriers in space, and the technical capabilities of underwater vehicles. The discussion remains unresolved with multiple competing perspectives presented.

Contextual Notes

Participants mention various assumptions about sound propagation, the conditions under which sound can travel, and the technical specifications of underwater vehicles, but these points remain open to interpretation and debate.

EternityMech
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Has it be done? And what's the sound barrier in space and can it be broken?
 
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There is no sound barrier in space.

In fresh water at 20 C, the speed of sound is ~1482 m/s; tough to beat in a medium that's about 1000 times as dense as air.
 
Certainly a normal sized object can in principle pass through a body of water faster than the speed of sound in the water. But in so doing I don't think you can say its "in water" anymore as the objects passage would create a large cavitation and vaporize the surrounding water.

An example I would imagine is substantial sized meteor hitting the ocean. Likely you have cases of the meteor drilling though to the ocean floor faster than conventional sound would travel from surface to floor.

But again I wouldn't call it breaking the sound barrier in water so much as breaking the water itself. The big difference is that water is effectively incompressible while air is compressible. This means the speed of sound in water is very very high. The expansion/compression happening on both sides of the shock wave formed by an object in the air would not necessarily change the phase. This can't really happen with water. The shock-wave formed would be a boundary between water and very high pressure steam.

I would add to negatron's comment ...
remember "In space, no one can hear you scream!"
 
no sound barrier in space? so if i yell in another galaxy Earth would hear it instantly?
 
EternityMech said:
no sound barrier in space? so if i yell in another galaxy Earth would hear it instantly?

In space no one can hear you scream.Sound needs a medium(solid liquid or gas) to travel through.No medium no sound.
 
aha... that's weird. so how would you go about hearing what the sun sounds like?
 
I would have to have a military expert such as Russ or Andre to verify this, but I'm pretty sure that both the US and the Russians developed supersonic torpedoes. They are essentially underwater rockets.
It seems to me that at least one of the designs vented pressurized air from the nose in order to form a bubble around itself and thus minimize water resistance.
 
EternityMech said:
aha... that's weird. so how would you go about hearing what the sun sounds like?

You get a fire-proof microphone and stick into the sun to a depth where the gas/plasma density is high enough to conduct sound.
You will need a really long cable, and it will deafen you.
 
Danger said:
You get a fire-proof microphone and stick into the sun to a depth where the gas/plasma density is high enough to conduct sound.
You will need a really long cable, and it will deafen you.

I've just got to ask - of what material will said microphone and cable be constructed? In order to avoid being vaporized, will you install the device at night?
 
  • #10
EternityMech said:
aha... that's weird. so how would you go about hearing what the sun sounds like?

Is it just me, or does this question smell funny?
 
  • #11
Tac-Tics said:
Is it just me, or does this question smell funny?

trolling a bit but i am curious what a nuclear fusion sounds like.
 
  • #12
EternityMech said:
trolling a bit but i am curious what a nuclear fusion sounds like.

Maybe I needed to say a bit more so it didn't come off that way.

Emergent phenomena only make sense in the domain which they apply. Billiard balls don't exert pressure along the surface of a pool table. A hydrogen atom doesn't have a temperature. And you can't have sound without having something to propagate it. Oh. And sentences don't have odors ;-)
 
  • #13
mvantuyl said:
In order to avoid being vaporized, will you install the device at night?

Of course.
I was thinking of a rubber cable in a braided silk sheath. The microphone housing would, naturally, have to be composed of Silly Putty.
 
  • #14
Well this thread made me laugh!
 
  • #15
Quantum_Grid said:
Well this thread made me laugh!
Jeez, but you are easily amused... :biggrin:
 
  • #16
Danger said:
I would have to have a military expert such as Russ or Andre to verify this, but I'm pretty sure that both the US and the Russians developed supersonic torpedoes. They are essentially underwater rockets.
It seems to me that at least one of the designs vented pressurized air from the nose in order to form a bubble around itself and thus minimize water resistance.
Rocket propelled torpedos yes, supersonic no. IIRC, they go a couple hundred mph.
 
  • #17
Danger said:
It seems to me that at least one of the designs vented pressurized air from the nose in order to form a bubble around itself and thus minimize water resistance.

The russian Shkval super cavitating torpedeo can do 400km/h using a film of bubbles

Particles (eg neutrinos) of course can go faster than light in water.
 
  • #18
Thanks, both Russ and Mgb for clarifying that. My memory is always a bit hazy.
 
  • #19
Could be Kursk sunk after Shkval torpedo accident.
 
  • #20
Borek said:
Could be Kursk sunk after Shkval torpedo accident.
It was widely reported that it was a torpedo accident, but I don't recall hearing a model name or number associated with it. It's quite possible that it was a Shkval. A warhead is a warhead, though, regardless of the delivery system. It could just as easily have been a defective mine, or whatever else they carry. (I do have the armaments of almost all subs available, but I don't know exactly where the book is since I'm in the midst of moving.)
 
  • #21
Sorry for dig this topic up, but It's match my curiosity as well.

I know that meteor hitting water faster than sound so it just drill water around.

But

What about object that originally under water?

like... something at bottom of ocean suddenly floating and gain speed up to March 2 or 3.

or alien submarine that can move faster than sound (The abyss)

.........

English is not my native language, Sorry of I'm wrong in spelling or gamma.
 
  • #22
EternityMech said:
aha... that's weird. so how would you go about hearing what the sun sounds like?
The average speed of sound in air at Earth's surface is around 330 meters per second. There is a very slim chance that enough air molecules or hydrogen molecules or some gas molecules would be lined up between here and the sun in just the right positions to propagate sound, but if they were, then I guess it would not be space in that region.
 
  • #23
EternityMech said:
aha... that's weird. so how would you go about hearing what the sun sounds like?

Well it's not really how the sun sounds like, but scientists can in fact "listen" to the sun. What they have done is simply just listen to the radio-waves that come from the sun. It was first heard back when the telephone was invented, through the background noise. No one knew where it was coming from, but years later (now) it's verified that it was indeed the sun.
 

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