If I were watching a sci-fi movie in which, each time a spaceship reached the speed of sound, it caused a conic vapor cloud, I'd figure the filmmaker liked computer-generated effects too much. But those cones are real, the result of something called the Prandtl-Glauert singularity. Truth is stranger than science fiction.
Stranger still are "plainbows," created when the vapor acts like a prism on the light passing through, breaking it into the colors of the spectrum. For an actual scientific explanation, you can click here. Or check out these pix.
Here are some garden-variety light-refracting vapor pix, all of which are real except one—see if you can pick out the fake.