Einstein explained · 1916–1918
Gravitational Waves
Gravitational waves are ripples in spacetime produced by changing distributions of mass, such as orbiting or merging compact objects.
moving masses → ripples in spacetime
))) GW (((
What it means
Strong gravitational waves can be produced when massive objects such as black holes or neutron stars accelerate in an uneven way. The waves travel through space at the speed of light.
Einstein's contribution
Einstein predicted gravitational waves in 1916 and improved the theory in 1918, including the quadrupole description of how gravitational radiation is produced.
Why it matters
Gravitational waves were directly detected in 2015. They now provide a new way to study black holes, neutron stars and violent events in the universe.
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Einstein’s key theories and contributions
1905Special RelativityHow motion changes measurements of space and time while the speed of light stays constant.Read explainer →1905Mass–Energy EquivalenceWhy mass and energy are connected by Einstein's famous relation E = mc².Read explainer →1907Equivalence PrincipleWhy free fall and acceleration gave Einstein the starting point for a new theory of gravity.Read explainer →1907Gravitational RedshiftHow gravity changes the frequency of light and the rate at which clocks run.Read explainer →1915General RelativityHow Einstein described gravity as curved spacetime shaped by matter and energy.Read explainer →1916–1917Quantum Theory of RadiationHow atoms absorb and emit light, including Einstein's prediction of stimulated emission.Read explainer →1917Cosmological ConstantWhy Einstein added Λ to his gravity equations and how the term returned in modern cosmology.Read explainer →