Supersonic speed is faster than the speed of sound, which is 768 miles per hour at sea level. Some familiar objects capable of traveling that quickly are bullets, whips and jet planes.
Supersonic aircraft flight is measured via Mach numbers, which are determined using a ratio that takes into account the velocity of the aircraft compared to the speed of sound. A speed rating of Mach 2 is twice the speed of sound, whereas a rating of Mach 1 is equal to the speed of sound. Objects that breach the sound barrier produce a characteristic noise, a sonic boom. Sonic booms are produced by objects moving so quickly that they sharply force air molecules apart as they travel. When the air collapses back into place, it creates a very loud sound.