Black Holes


In 1783 geologist John Michell first thought of the idea of an object massive enough that even light could not escape its gravitational pull

In 1796 Pierre-Simon Laplace noted that as a result of Newtonian theory, light cannot escape from an object of large enough mass and small enough radius (Shapiro 336). Thus he promoted Michell's idea

In 1915 Albert Einstein's general relativity papers came out after previously showing that light's motion is influenced by gravity. Shortly later, Karl Schwarzschild derived the solution for the gravitational field of a point mass according to general relativity. Einstein agreed with Schwarzschild, now we call non-rotating electrically neutral spherical black holes "Schwarzschild black holes" (Shapiro 337).

Arthur Eddington and Lev Landau reject the idea that stars could collapse to black holes in 1935 and 1932 respectively. As one of the first to accept and promote Einstein's theory of general relativity, Eddington acknowledges that black holes would inevitably form as a result of the evolution of massive stars. However, he insists that there must be some sort of law of nature to "prevent the star from acting in such an absurd way". Landau as well acknowledged that according to quantum theory, nothing prevents the system of a star from collapsing to a point. Landau, like Eddington, insisted that all massive stars must posses regions in which the laws of quantum mechanics are violated (Shapiro 337). *Later, in 1980, Eddington is accused of having delayed the research on black holes because of his shortsightedness regarding the topic.

In 1939 Oppenheimer and Snyder revive the black hole discussion after calculating how a homogeneous sphere of gas would collapse according to general relativity. The result is profound: the sphere eventually gets cut off from all communication with the rest of the universe (Shapiro 338).

In 1968 J.A. Wheeler coins the term "black hole" (Shapiro 338).

As a result of R. Kerr's 1963 solutions to Einstein's vacuum field equations, we now know the Kerr-Newman geometry which provides a complete description of the gravitational and electromagnetic fields of a stationary black hole (Shapiro 338)

The discoveries of quasars (1963), pulsars (1968), and compact X-ray sources (1962) helped motivate the study of black holes. Observations of X-ray source Cygnus X-1 in the 1970s provided the first plausible evidence that black holes could actually exist in space. Today, Sagittarius A* is commonly observed because it is the likely location of a supermassive black hole in the Milky Way galaxy (Shapiro 338).