Temperature governs every act of creation and decay, yet remains treated as a derived scalar rather than a geometric coordinate. Here we demonstrate that temperature defines a universal sixth dimension (Θ) orthogonal to space, time and energy–mass. Within this manifold, state change across materials, planets and stars follows one invariant law is the transformation velocity along the thermal axis. Empirical evidence from laboratory heat conduction, planetary warming and stellar fusion collapses onto a single scaling curve with (α = 0.50 ± 0.05), revealing temperature as the geometric coordinate of transformation.