1758 - Rudjer Josip Boscovich developes his Theory of forces, where gravity can be repulsive on small distances. So according to him such strange classical bodies, similar to white holes, can exist, which won't let other bodies to reach their surfaces,
1917 - Paul Ehrenfest gives conditional principle a three dimensional space,
1918 - Hans Reissner and Gunnar Nordström solve the Einstein-Maxwell field equations for charged spherically-symmetric non-rotating systems,
1918 - Friedrich Kottler gets Schwarzschild solution without Einstein vacuum field equations,
1923 - George Birkhoff proves that the Schwarzschild spacetime geometry is the unique spherically symmetric solution of the Einstein vacuum field equations,
1939 - Robert Oppenheimer and Hartland Snyder calculate the gravitational collapse of a pressure-free homogeneous fluid sphere and find that it cuts itself off from communication with the rest of the Universe,
1963 - Roy Kerr solves the Einstein vacuum field equations for uncharged symmetric rotating systems,
1964 - Roger Penrose proves that an imploding star will necessarily produce a singularity once it has formed an event horizon,
1965 - Ezra Newman, E. Couch, K. Chinnapared, A. Exton, A. Prakash, and Robert Torrence solve the Einstein-Maxwell field equations for charged rotating systems,
1968 - Brandon Carter uses Hamilton-Jacobi theory to derive first-order equations of motion for a charged particle moving in the external fields of a Kerr-Newman black hole,
1969 - Roger Penrose discusses the Penrose process for the extraction of the spinenergy from a Kerr black hole,
