Mach number temperature generally decreases with increasing altitude between sea level and , the speed of sound also decreases. For example, the standard atmosphere model lapses temperature to at altitude, with a corresponding speed of sound (Mach1) of , 86.7% of the sea level value. While the terms "subsonic" and "supersonic", in the purest sense, refer to speeds below and above the local speed of sound respectively, aerodynamicists often use the same terms to talk about particular ranges of Mach values. This occurs because of the presence of a "transonic regime" around M = 1 where approximations of the Navier-Stokes equations used
Mach: The First Colony Mach: The First Colony Mach: The First Colony is a role-playing game published by Alliance Publications in 1983. "Mach: The First Colony" is a science-fiction system in which the players are mercenaries on a frontier planet. The planet, its societies, and mixed technologies are described in detail. The first book (32 pages) covers character creation and combat; the second (32 pages) covers skills and creatures. The game includes an introductory scenario (16 pages). "Mach: The First Colony" was designed by Michael Lange with Martin Miller, and published by Alliance Publications in 1983 as a boxed set containing a 32-page book,