Image credit NASA; Image source; larger image
Shock Diamonds and Mach Disks
When the speed of the gases in a jet or rocket exhaust exceeds the speed of sound, a dazzling pattern results called "shock diamonds" or "Mach disks," as shown in this photo of the SR-71 Blackbird. The diamonds are created by crisscrossing shock waves in the exhaust.
You can see shock diamonds in a static rocket test in this NASA video. For more information, check out Shock Diamonds and Mach Disks.
Faster than Sound
Visit Nova's Faster than Sound to find out how Chuck Yeager broke the sound barrier in 1947 in the Bell X-1. You'll find recollection from the X-1's pilots and one of the X-1's designers, and learn about the historical background as well. In the Speed Machines section, you can find out about speed records in the air, on land, and on water.