# [SCI] Gravitational Wave Theory

**Gravitational Wave Theory** predicts that accelerating masses create ripples in spacetime — gravitational waves — that propagate at the speed of light and carry energy away from the source.

## Overview

Einstein derived gravitational waves from linearised GR (1916) and computed the power radiated (quadrupole formula, 1918). For decades their existence was debated. Hulse and Taylor discovered the binary pulsar PSR 1913+16 (1974) and showed it was losing orbital energy at exactly the rate predicted by GR gravitational wave emission — indirect proof. Direct detection required laser interferometers sensitive to displacements of 10⁻¹⁸ m — 1000 times smaller than an atomic nucleus — achieved by LIGO in 2015 (from a binary black hole merger).

## Key Figures & Recognition

- **Albert Einstein** (1879–1955): Predicted gravitational waves, 1916.
- **Russell Hulse** (1950–) & **Joseph Taylor** (1941–): Binary pulsar. **Nobel Prize 1993**.
- **Kip Thorne** (1940–), **Rainer Weiss** (1932–), **Barry Barish** (1936–): LIGO. **Nobel Prize 2017**.

## Seminal Papers

- Einstein, A. "Näherungsweise Integration der Feldgleichungen der Gravitation." *Sitzungsber. Preuss. Akad. Wiss.* (1916).
- [Abbott, B.P. et al. (LIGO). "Observation of Gravitational Waves from a Binary Black Hole Merger." *PRL* 116 (2016)](https://doi.org/10.1103/PhysRevLett.116.061102)

## What This Enables

- **[TECH] LIGO Gravitational Wave Detector** — LIGO was designed and built specifically to detect the spacetime ripples predicted bythat linearised GR predicts.
- **[SCI] Gravitational Wave Astronomy** — Confirmed GW detections opened a newan observational window entirely unavailable to electromagnetic telescopes.

# Parents

* [SCI] Analytical Mechanics
* [SCI] General Relativity
* [SCI] General Relativity