Relativity
Time Dilation
The relativistic effect by which time runs slower for fast-moving observers and deeper in a gravitational field. It is measured every day — GPS satellites must correct for it — and it steepens near neutron stars and black holes, where clocks near the horizon crawl relative to distant ones. Even distant supernovae are seen to fade in slow motion as the Universe expands.
Highlights
- ›Clocks slow near mass and at high speed — measured, not theory
Related physics & astronomy
Across fundamental physics
Knowledge connections
- Associated withSpecial Relativity
- Associated withGeneral Relativity
- Associated withLength Contraction
- Associated withSpacetime
- Associated withLength Contraction
Sources
The primary and reference sources this topic draws on.
- NASANational Aeronautics and Space Administration
Mission data, planetary science, space telescopes, and public-domain imagery.
Most NASA-produced imagery is in the public domain; individual items are checked for usage terms before publication.