This slideshow exhibit briefly shows the progression of the theory of general relativity from Einstein’s initial three publications in November 1915 through proofs offered by Karl Schwarzchild, David Hilbert, Arthur Eddingtion, and others; to the revival of interest in general relativity after World War II; and to the results expected from new gravitational detectors like LIGO and eLISA.
A joint effort of AIP, the Einstein Papers Project at CalTech, and the Albert Einstein Archives at the Hebrew University of Jerusalem.
As early as 1912 Albert Einstein (1879–1955) worked on the theory of general relativity. In November 1915, he published three papers on the topic. They were the culmination of years of intense work. Soon thereafter he completed an overview of the theory and published a popular account.
In 1915, Karl Schwarzschild (1873–1916) proposed the first exact solution to Einstein’s field equations of general relativity. It contained a singularity that, under certain conditions, produces what today is called a black hole.
In 1922 Alexander Friedman (1888–1925) discovered non-static solutions to Einstein’s cosmological equation and predicted that the universe can expand and, in some scenarios, also contract, collapse, and be born again. Even before the astronomical discovery of the red shift, Friedman was able to estimate the age of the universe at the order of 10 billion years.
The results of observations carried out by British scientists during the 29 May 1919 solar eclipse confirmed the value of relativistic gravitational light deflection predicted by Einstein, seen here in the company of Arthur S. Eddington, Paul Ehrenfest, H. A. Lorentz, and W. de Sitter in Leyden, late September 1923.
The Einstein Tower at the Potsdam Observatory (right) was designed to measure solar gravitational redshift. It was inaugurated in August 1921 during the annual meeting of the German Astronomical Society, at which Einstein is seen with the astronomer Hans Ludendorff (above), its director.
An international effort to observe the solar eclipse of 21 September 1922 was mounted by astronomers from the U.S., Australia, India, and Canada. The Lick Observatory team, led by William W. Campbell (1862–1938), installed the 1.52 meter (5 foot) Einstein camera in Wollal, Western Australia, and confirmed the values for light deflection predicted by general relativity.
Georges Lemaître (1894–1966), seen with Einstein at Caltech in 1933 (right), proposed the idea of an expanding universe in 1927. On the basis of observations carried out with the 100-inch Hooker telescope at the Mt. Wilson Observatory between 1924 and 1929, Edwin Hubble (1889–1953) (above) showed that the universe was expanding and extended well beyond the Milky Way.
While he was a visiting scientist at the California Institute of Technology, Einstein visited the Mt. Wilson Observatory for the first time on 29 January, 1931. In this photograph (right) he is seen with Charles St. John examining images at the 150-foot Solar Tower, whose spectroheliograph logbook for that day is reproduced above.
The equations at the upper left are part of Einstein’s approach to a unified field theory of gravity and electromagnetism that he developed in the mid-1940s. The equations are based on a generalization of the pseudo-Riemannian geometry he used in the general theory of relativity.
The sentence at the top right reads: “He who, against his better judgment, says ‘yes sir, no sir, three bags full sir’ to the aberrations of the crazy crowd, does not deserve that the sun is shining on him.”
After World War II, John A. Wheeler (1911–2008) contributed significantly to the revival of interest in general relativity, which had been largely ignored in the previous few decades. At the 1957 Chapel Hill Conference on The Role of Gravitation in Physics, Wheeler kept a detailed notebook of the proceedings and discussions.
Einstein predicted the existence of gravitational waves in 1916. Although indirect evidence has been provided by measurements of the Hulse-Taylor binary system, definitive results are expected from current and future gravitational detectors, such as LIGO (Laser Interferometer Gravitational-Wave Observatory) and eLISA (Evolved Laser Interferometer Space Antenna).