Recently released by the US Navy, these photos document an FA-18 Hornet as it shatters the sound barrier. The event took place on July 7, 1999 off the coast of Pusan, South Korea. Apparently the cloud around the craft is due to Prandtl-Glauert singularity.
I asked Wikipedia what Prandtl-Glauert singularity meant and discovered it has something to do with the pressure that exists as an object breaks the sound barrier. The rest of the explanation went over my head. Anyone else out there have a better explanation?