In zero gravity, object translations, rotations, vibrations, scale changes, and inversions in space do not change object geometric shape. Zero-gravity four-dimensional space-time has symmetry {conformal symmetry} {conformal symmetry group} that preserves geometric shape, because metric-scale changes {Weyl transformation} leave proper time and proper length unchanged. Mathematically, the Poincaré group, scale invariance (dilation or dilatation), and inversion-translation-inversion (special conformal transformation) have conformal symmetry and preserve geometric shape.
Physical Sciences>Physics>Relativity>Space-Time
5-Physics-Relativity-Space-Time
Outline of Knowledge Database Home Page
Description of Outline of Knowledge Database
Date Modified: 2022.0224