User talk:Tomcat Cruiser

Speed of sound changes with altitude
Per Mach number, which you linked to in your edit summary:
 * Since the speed of sound increases as the ambient temperature increases, the actual speed of an object traveling at Mach 1 will depend on the temperature of the fluid through which the object is passing. Mach number is useful because the fluid behaves in a similar manner at a given Mach number, regardless of other variables. So, an aircraft traveling at Mach 1 at 20 °C (68 °F) at sea level will experience shock waves just like an aircraft traveling at Mach 1 at 11,000 m (36,000 ft) altitude at −50 °C (−58 °F), even though the second aircraft is only traveling 86% as fast as the first.). National Aeronautics and Space Administration website page "Mach Number", NASA. (Emphasis added.)

Thanks. - BilCat (talk) 02:50, 10 August 2016 (UTC)