The speed of sound waves in air is a little faster than surface water waves, of course: over 700 miles per hour! So if we're going to have a falcon to go faster than this and outrun its own sound, we'll need an improved, supersonic Falcon.
You can also see what's not so obvious, that the boom has a specific shape: it's
a cone with the Falcon at the tip. (A wedge in our two-dimensional
water wave version...imagine the circles as spheres trailing the plane) In the
diagram, the plane starts from 0 and moves the length of the horizontal red line to the right.
The sound from zero has now reached the big circle, and the upper red line is how far
the sound has moved. This diagram shows the horizontal line as
twice as long as the upper, which means this
plane is moving twice as fast as sound ("Mach 2" in the jargon)
since it's traveled twice as far as sound in the same amount of time.
Can you visualize what the diagram would look like at Mach 3?
Faster planes would have a sharper cone. You can see this in the falcon/fish Java simulation two pages previous: drag your mouse at different speeds faster than the waves and note the angle of the "cone".
The "Sound Barrier" refers to the turbulent shaking of aircraft flying near the speed of sound, where the plane is in those piled up waves. Do you know who was the first person to go faster than sound? (did you know he had fallen from a horse and cracked some ribs the night before?) A more graphical version. A trickier question: what was the first thing someone made go faster than sound? Photographic proof of correctness of the answer, by some high school students.
Do you know what happens with light waves, when the source exceeds the speed of light? Hah, you say, I know that trick: you can't go faster than light! Well, actually physicists see tiny particles go faster than light all the time! In fact, they use the "photic boom" created by such particles in big tanks of water to measure the particle speeds. No, that isn't the official name for the light cone they create, it's the Cerenkov Effect, but it's very analogous to a sonic boom. What's the trick about exceeding the speed of light? Light, like sound, has different speeds in different materials, and you can't go faster than light speed in a vacuum. An easily forgotten detail, but the particles don't forget it and nonchalantly exceed light speed in water, where it's lower than in vacuum. Cerenkov light is most easily seen in a nuclear reactor blue glow. It's used in instruments, like Cerenkov telescopes (air isn't vacuum either) including neutrino telescopes using polar ice or the ocean!, and a student particle detector demo.
Catch the next wave!
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