Spectacular images have captured a rare visual phenomenon caused when a fighter jet nears the speed of sound.
As the plane pierces droplets of vapour in the air it creates a beautiful cone-shaped cloud known as a "shock collar", scientists say.
"Some of the air moving around the plane is going at supersonic speed, even if the plane isn't," NASA aeronautics expert Peter Cohen told US network ABC.
"And if there's humid, moist air around it, you get what you see in the picture."
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