Science
What is General relativity?
General relativity is Einstein's 1915 theory of gravity, which describes gravity not as a force but as the curving of space and time by mass and energy. Massive objects bend spacetime, and other objects move along those curves — which we feel as gravity.
See it, don’t just read it.
Watch a 2-minute lesson with voice + animation that explains general relativity.
Key things to understand
- 1Mass and energy curve the fabric of spacetime; objects follow the straightest path through that curved space.
- 2What we experience as gravitational 'pull' is really this curvature guiding motion.
- 3It predicts light bends around massive objects (gravitational lensing), confirmed during a 1919 eclipse.
- 4It explains black holes, the expansion of the universe, and tiny shifts in planetary orbits.
- 5It extends special relativity to include gravity and accelerating frames.
Frequently asked questions
- How is general relativity different from Newton's gravity?
- Newton described gravity as a force between masses; Einstein showed it's the curvature of spacetime. Einstein's version is more accurate, especially near very massive objects.
- What is gravitational lensing?
- Massive objects bend the path of light passing nearby, so distant galaxies can appear distorted or magnified — direct evidence that mass curves spacetime.
- Does GPS rely on general relativity?
- Yes. Clocks on satellites run slightly faster due to weaker gravity up there; GPS corrects for this relativistic effect to pinpoint locations accurately.