Concorde's speed is measured in Mach numbers - the ratio of the aircraft's speed in air to the local speed of sound. Subsonic aircraft like Boeing 747s travel at less than Mach 1. When Concorde goes supersonic she travels at Mach 2 - twice the speed of sound, around 1350 mph.
Researchers in Australia are investigating hypersonic travel. Their experimental jets zoom around at Mach 8 - 8 times the speed of sound.
|Launch of a Hyshot hypersonic jet.|
Image: University of Queensland