The term IT TRAVELS AT MACH 1 can be summarized as referring to SOUND, which is a type of mechanical wave that travels through air, water, and other materials at the speed of Mach 1, or approximately 767 miles per hour. SOUND is a form of energy that is created by vibrations and propagates through a medium such as air, water, or solid objects. It is used for communication, entertainment, and other purposes.