Einstein, Albert (1879–1955)
- Physicist of Swiss birth who lived most of his life in the US His work on relativity altered the face of modern physics and produced many insights of value to astronomy. His work altered many fields of science but Einstein is now recalled mainly for proving that matter and energy are interlinked and that time itself can vary with velocity and the presence of fields such as gravitation. In astronomy, his work illuminates everything from the behaviour of dust in the solar system to the origin of the universe itself. The bending of starlight by the gravitational field of the Sun, observed at the solar eclipse of 1919 was one of the key proofs of relativity, which also accounts for previously unexplained precession of the orbit of Mercury. A US X-ray astronomy satellite, Einstein, was launched in 1978. His name has attached itself to many other objects and phenomena, e.g. Einstein rings, the arcs of light or other radiation formed by gravitational lensing.