Editing Timeline of black hole physics (section)

=== Before 1960s ===
* 1909&nbsp;— [[Albert Einstein]], together with [[Marcel Grossmann]], starts to develop a theory which would bind [[metric tensor]] ''g''<sub>ik</sub>, which defines a [[space]] [[geometry]], with a source of [[gravity]], that is with [[mass]]
* 1910&nbsp;— [[Hans Reissner]] and [[Gunnar Nordström]] define [[Reissner–Nordström metric|Reissner–Nordström]] [[gravitational singularity|singularity]], [[Hermann Weyl]] solves special case for a [[point source|point-body source]]
*1915&nbsp;— [[Albert Einstein]] presents ([[David Hilbert]] presented this independently five days earlier in Göttingen) the complete [[Einstein field equations]] at the [[Prussian Academy of Sciences|Prussian Academy]] meeting in Berlin on 25 November 1915<ref name=Thorne>{{Cite book|title=Black holes and time warps : Einstein's outrageous legacy|last=Thorne|first=Kip S.|isbn=0393035050|location=New York|oclc=28147932|year=1994|url-access=registration|url=https://archive.org/details/blackholestimewa0000thor}}</ref>
* 1916&nbsp;— [[Karl Schwarzschild]] solves the [[Einstein field equations#Vacuum field equations|Einstein vacuum field equation]]s for [[electric charge|uncharged]] spherically symmetric non-rotating systems<ref>{{cite journal |last1=Levy |first1=Adam |title=How black holes morphed from theory to reality |journal=Knowable Magazine |date=January 11, 2021 |doi=10.1146/knowable-010921-1|s2cid=250662997 |doi-access=free |url=https://knowablemagazine.org/article/physical-world/2021/how-black-holes-morphed-theory-reality |access-date=25 March 2022}}</ref>
* 1917&nbsp;— [[Paul Ehrenfest]] gives conditional principle a three-dimensional space
* 1918&nbsp;— [[Hans Reissner]]<ref>{{cite journal |last=Reissner |first=H. |date=1916 |title=Über die Eigengravitation des elektrischen Feldes nach der Einsteinschen Theorie |url=https://zenodo.org/record/1447315 |journal=Annalen der Physik |language=en |volume=355 |issue=9 |pages=106–120 |bibcode=1916AnP...355..106R |doi=10.1002/andp.19163550905 |issn=0003-3804}}</ref> and [[Gunnar Nordström]]<ref>{{cite journal |last=Nordström |first=G. |date=1918 |title=On the Energy of the Gravitational Field in Einstein's Theory |journal=Koninklijke Nederlandsche Akademie van Wetenschappen Proceedings |volume=20 |issue=2 |pages=1238–1245 |bibcode=1918KNAB...20.1238N}}</ref> solve the [[Einstein field equations#Einstein-Maxwell equations|Einstein–Maxwell field equations]] for charged spherically symmetric non-rotating systems
* 1918&nbsp;— [[Friedrich Kottler]] gets [[Schwarzschild metric|Schwarzschild solution]] without Einstein vacuum field equations
* 1923&nbsp;— [[George David Birkhoff]] proves that the Schwarzschild [[spacetime]] geometry is the unique spherically symmetric solution of the Einstein vacuum field equations
* 1931&nbsp;— [[Subrahmanyan Chandrasekhar]] calculates, using [[special relativity]], that a non-rotating body of [[electron-degenerate matter]] above a certain limiting mass (at 1.4 solar masses) has no stable solutions
* 1939&nbsp;— [[Robert Oppenheimer]] and [[Hartland Snyder]] calculate the [[gravitational collapse]] of a pressure-free [[homogeneity (physics)|homogeneous]] fluid sphere into a [[black holes|black hole]]<ref>{{cite journal | last1=Oppenheimer | first1=J. R. | last2=Snyder | first2=H. | title=On Continued Gravitational Contraction | journal=Physical Review | publisher=American Physical Society (APS) | volume=56 | issue=5 | date=1 September 1939 | issn=0031-899X | doi=10.1103/physrev.56.455 | pages=455–459| doi-access=free | bibcode=1939PhRv...56..455O }}</ref>
*1939&nbsp;- Using the work of [[Richard Chace Tolman]], Robert Oppenheimer and [[George Volkoff]] calculate the [[Tolman-Oppenheimer-Volkoff limit|upper mass limit]] of a cold, non-rotating [[neutron star]] to be approximately 0.7 solar masses.<ref>{{cite journal |first=R. C. |last=Tolman |date=1939 |title=Static Solutions of Einstein's Field Equations for Spheres of Fluid |journal=[[Physical Review]] |volume=55 |issue=4 |pages=364–373 |doi=10.1103/PhysRev.55.364 |bibcode=1939PhRv...55..364T |url=https://resolver.caltech.edu/CaltechAUTHORS:TOLpr39}}</ref><ref>{{cite journal |first1=J. R. |last1=Oppenheimer |first2=G. M. |last2=Volkoff |date=1939 |title=On Massive Neutron Cores |journal=[[Physical Review]] |volume=55 |issue=4 |pages=374–381 |doi=10.1103/PhysRev.55.374 |bibcode=1939PhRv...55..3740}}</ref>
* 1958&nbsp;— [[David Finkelstein]] theorises that the [[Schwarzschild radius]] is a [[causality (physics)|causality]] barrier: an [[event horizon]] of a black hole<ref>{{cite journal |last1=Finkelstein
 |first1=David |title=Past-future asymmetry of the gravitational field of a point particle |journal=Physical Review |volume=110 |issue=4 |pages=965–967 |year=1958 |doi=10.1103/PhysRev.110.965
 |bibcode=1958PhRv..110..965F}}</ref>