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SESK: Stuff Everyone Should Know · sesk.info/aero-sound-barrier-drag

Scientists once thought the 'sound barrier' could not be crossed. What was it really?

A big rise in drag near the speed of sound.

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  1. A solid wall of air
  2. A rise in drag near the speed of sound ✔
  3. A layer of the atmosphere

Why: Near Mach 1, air squeezes together and shock waves form, so drag jumps. Airplanes with enough power and the right shape fly right through it.

Huh, didn't know that: Because drag is so high near Mach 1, airplanes do not cruise near that speed.

The dad joke
Why couldn't the sound barrier stop the X-1? It was all bark and no bite.
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References

Answer: A rise in drag near the speed of sound. Near Mach 1, air squeezes together and shock waves form, so drag jumps. Airplanes with enough power and the right shape fly right through it.

  1. Mach Number, NASA Glenn Beginner's Guide to Aeronautics www.grc.nasa.gov/www/k-12/airplane/mach.html
    the sound barrier was only an increase in the drag near sonic conditions because of compressibility effects.
    Checked 2026-10-10.

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