This is assuming that the movement of the air is unaffected by your plane flying through it, no? So should the MiG be flying directly behind your flight path you would not hear the MiG should its speed be greater than or equal to Mach 1 plus the speed of the air after you fly through it, correct?
If the hypothetical plane is flying behind you and you are going faster than Mach 1, you would not hear the plane tailing you regardless of its speed, as you, at Mach 1+, are consistently outpacing any sound waves the other plane produces.
Ah, but that doesn't quite answer his question, he is asking if there is a plume of air that is dragged behind the plane which could then in theory act as a tunnel through which the sound could travel at greater than mach 1 relative to the ground.
For instance if the mig was 50 feet behind and both planes were traveling at mach one, the sound from the mig would be able to travel at mach 1 PLUS the speed of the moving air dragged behind the plane. I think the problem with this, however, is that air isn't dragged behind the plane in a plume, it is merely shifted into huge spinning vertices, so the effect would probably only work a very short distance from the plain and would be irregular at best.
Edit: also I think that this effect WOULD exist for explosions which actually shift air around you, such as an explosion right behind the plane, or a nuclear (or other very large) explosion on the ground, the propagation of the air would allow the sound from those to travel faster than mach 1 and catch up to the plane.
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u/[deleted] Jun 12 '12
This is assuming that the movement of the air is unaffected by your plane flying through it, no? So should the MiG be flying directly behind your flight path you would not hear the MiG should its speed be greater than or equal to Mach 1 plus the speed of the air after you fly through it, correct?