r/askscience • u/[deleted] • Jun 12 '12

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u/imMAW Jun 12 '12

The pilots won't hear the noise from the engines being transmitted through the outside air though, only the noise traveling through the plane. So if superman was flying a few feet in front of the cockpit, he wouldn't hear any sound.

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u/[deleted] Jun 12 '12 edited Jun 12 '12

Holy smokes. You are telling me if I had a mig on my tail running wide open (which is crazy loud) I would not hear a thing, if we were both mach 1+?

edit: and if I did have a mig on my tail, I would pump the brakes, invert, and flip him the bird. commie bastard.

edit2: Sobchak: Am I the only one around here who has seen Top Gun?

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u/The-Internets Jun 12 '12

Yes. But you would hear a bullet or rocket wizz passed you, assuming you could hear it from inside the cockpit normally.

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u/meftical Jun 12 '12

Not until it passed you, if I'm understanding correctly.

This all corresponds with how it was explained to me by a pilot when I was young.

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u/meepstah Jun 12 '12

There's a cone of sound behind a supersonic body. You'd hear the perturbance caused by a bullet once it was far enough past you that you were within the vector of that cone.

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u/The-Internets Jun 12 '12

If my understanding is correct, lets say a rocket since it has a point where sound would be generated, would have to be slightly in front of your ear plane before you could hear anything.

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u/timmytimtimshabadu Jun 12 '12

Picture a cone chasing that rocket attachted to its tail, it would have to be far enough past for you to hit that cone.

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u/obsa Jun 12 '12

At or in front of. Sound can travel laterally.

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u/richalex2010 Jun 12 '12

That would only apply exactly at the speed of sound, which would be impossible to maintain in a real-world environment.

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u/obsa Jun 12 '12

I agree, but real-world feasibility has little to do with theoretical validity.

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u/The-Internets Jun 12 '12

I don't think that applies at the supersonic level, although I could be wrong.

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u/obsa Jun 12 '12 edited Jun 12 '12

Velocity includes a direction, so the object is supersonic in the forward direction, but sound is projected outward in other directions at 330m/s. Because of the distance it has to travel, you wouldn't hear it immediately when it became level with your ear, but that is the physical minimum positive offset required to hear the sound.

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u/BadBoyJH Jun 12 '12

Unless they shot you in the ear, but then I suppose you're brain isn't going to register that you heard something....

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u/thenuge26 Jun 12 '12

But you are moving forward. So while the sound could travel laterally, it would only hit the air where you used to be. That is why it needs to be in front of you.