Editing Timeline of black hole physics

{{short description|None}}
{{More references|date=March 2025}}
'''[[Timeline]] of [[black hole]] [[physics]]'''

==Pre-20th century==
* 1640&nbsp;— [[Ismaël Bullialdus]] suggests an [[inverse-square law|inverse-square]] gravitational force law
* 1676&nbsp;— [[Ole Rømer]] demonstrates that [[Rømer's determination of the speed of light|light has a finite speed]]<ref>P. 328 of {{Cite journal| issn = 0021-1753| volume = 31| issue = 2| pages = 327–379| last1 = Romer| first1 = M.| last2 = Cohen| first2 = I Bernard| title = Roemer and the First Determination of the Velocity of Light (1676)| journal = Isis| accessdate = 2023-03-24| date = 1940| doi = 10.1086/347594| url = https://www.jstor.org/stable/225757| jstor = 225757| hdl = 2027/uc1.b4375710| s2cid = 145428377| hdl-access = free}}</ref>
* 1684&nbsp;— [[Isaac Newton]] writes down his inverse-square [[Gravity|law of universal gravitation]]<ref>{{Cite book |last=More |first=Louis Trenchard |url=https://archive.org/details/isaacnewtonbiogr0000loui/page/327 |title=Isaac Newton: A Biography |publisher=Dover Publications |year=1934 |page=327}}</ref>
* 1758&nbsp;— [[Rudjer Josip Boscovich]] develops his theory of forces, where [[gravity]] can be repulsive on small distances. This implied that strange classical bodies that would not allow other bodies to reach their surfaces, such as what we know call <em>[[white hole|white holes]]</em>, could exist.<ref>{{cite book|title=Cohesion: A Scientific History of Intermolecular Forces|author=Rowlinson, J.S.|date=2002|publisher=Cambridge University Press|isbn=9781139435888|url=https://books.google.com/books?id=Apyi_FXKnSkC}}</ref>
* 1784&nbsp;— [[John Michell]] discusses classical bodies which have [[escape velocity|escape velocities]] greater than the [[speed of light]]<ref>{{Cite web |last=Platts-Mills |first=Ben |date=2 July 2024 |title=The forgotten priest who predicted black holes – in 1783 |url=https://www.bbc.com/future/article/20240626-the-priest-who-predicted-black-holes-in-1783 |access-date=2025-01-03 |website=[[BBC]]}}</ref>
* 1795&nbsp;— [[Pierre-Simon Laplace|Pierre Laplace]] discusses classical bodies which have escape velocities greater than the speed of light<ref>Laplace, P.-S. (1799). ''Allgemeine geographische Ephemeriden herausgegeben von [[Franz Xaver von Zach|F. von Zach]]''. IV. Band, I. Stück, I. Abhandlung, Weimar; translation in English: {{cite book |last1=Hawking |first1=Stephen W. |last2=Ellis |first2=George F.R. |title=The Large Scale Structure of Space-Time  |year=1973 |publisher=Cambridge University Press |isbn=978-0-521-09906-6 |pages=365ff|title-link=The Large Scale Structure of Space-Time }}</ref><ref>Colin Montgomery, Wayne Orchiston and Ian Whittingham, [http://www.narit.or.th/en/files/2009JAHHvol12/2009JAHH...12...90M.pdf "Michell, Laplace and the origin of the Black Hole Concept"] {{Webarchive|url=https://web.archive.org/web/20140502005017/http://www.narit.or.th/en/files/2009JAHHvol12/2009JAHH...12...90M.pdf |date=2 May 2014 }}, ''Journal of Astronomical History and Heritage'', '''12'''(2), 90–96 (2009).</ref>
* 1798&nbsp;— [[Henry Cavendish]] measures the [[gravitational constant]] ''G''{{sfn|Poynting|1911|p=385}}<ref>'The aim [of experiments like Cavendish's] may be regarded either as the determination of the mass of the Earth,...conveniently expressed...as its "mean density", or as the determination of the "gravitation constant", G'. Cavendish's experiment is generally described today as a measurement of ''G''.' (Clotfelter 1987 p. 210).</ref>
* 1876&nbsp;— [[William Kingdon Clifford]] suggests that the motion of matter may be due to changes in the geometry of space

==20th century==
=== 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|url-access=subscription }}</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..374O}}</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>

=== 1960s ===
* 1963&nbsp;— [[Roy Kerr]] solves the Einstein vacuum field equations for uncharged symmetric rotating systems, deriving the [[Kerr metric]] for a [[rotating black hole]]<ref>{{cite journal |last=Kerr |first=Roy P. |author-link=Roy Kerr |date=1963 |title=Gravitational Field of a Spinning Mass as an Example of Algebraically Special Metrics |journal=Physical Review Letters |volume=11 |issue=5 |pages=237–238 |doi=10.1103/PhysRevLett.11.237 |bibcode=1963PhRvL..11..237K }}</ref><ref >Melia, Fulvio (2009). "Cracking the Einstein code: relativity and the birth of black hole physics, with an Afterword by Roy Kerr", Princeton University Press, Princeton, {{ISBN|978-0226519517}}</ref>{{rp|69–81}}
* 1963&nbsp;— [[Maarten Schmidt]] discovers and analyzes the first [[quasar]], [[3C 273]], as a highly red-shifted [[active galactic nucleus]], a billion light years away<ref>{{cite news|title=Maarten Schmidt, First Astronomer to Identify a Quasar, Dies at 92|url=https://www.nytimes.com/2022/09/22/science/space/maarten-schmidt-dead.html|first=Clay|last=Risen|date=22 September 2022|access-date=22 September 2022|newspaper=[[The New York Times]]}}</ref>
* 1964&nbsp;— [[Yakov Borisovich Zel'dovich|Yakov Zel’dovich]] and independently [[Edwin Salpeter]] propose that accretion discs around [[supermassive black holes]] are responsible for the huge amounts of energy radiated by [[quasar]]s<ref name="Thorne" />
* 1964&nbsp;— [[Hong-Yee Chiu]] coins the word ''quasar'' for a 'quasi-stellar radio source' in his article in [[Physics Today]]<ref>{{cite journal |last1=Chiu |first1=Hong-Yee |title=Gravitational collapse |journal=Physics Today |date=May 1964 |volume=17 |issue=5 |pages=21–34 |doi=10.1063/1.3051610 |bibcode=1964PhT....17e..21C |url=https://physicstoday.scitation.org/doi/pdf/10.1063/1.3051610 |quote=So far, the clumsily long name 'quasi-stellar radio sources' is used to describe these objects. Because the nature of these objects is entirely unknown, it is hard to prepare a short, appropriate nomenclature for them so that their essential properties are obvious from their name. For convenience, the abbreviated form 'quasar' will be used throughout this paper.|doi-access=free }}</ref><ref>{{cite web|url=http://siarchives.si.edu/collections/siris_arc_290743|title=Hong-Yee Chiu (b. 1932)|publisher=Smithsonian Institution Archives, Accession 90-105, Science Service Records, Image No. SIA2008-0238|accessdate=April 6, 2013|quote=Summary: Chinese-American astrophysicist Hong-Yee Chiu (b. 1932) is credited with coining the term "quasar" in 1964.}}</ref>
* 1964&nbsp;— The first recorded use of the term "black hole" in writing, by journalist Ann Ewing<ref>{{Cite book |last=Bartusiak |first=Marcia |title=Black Hole: How an Idea Abandoned by Newtonians, Hated by Einstein, and Gambled On by Hawking Became Loved |date=2015 |publisher=Yale University Press |isbn=978-0-300-21363-8 |location=New Haven, CT}}</ref>
* 1965&nbsp;— [[Roger Penrose]] proves that an imploding star will necessarily produce a singularity once it has formed an [[event horizon]]<ref name=Penrose1965>{{cite journal|last1=Penrose|first1=Roger|title=Gravitational Collapse and Space-Time Singularities|journal=Physical Review Letters|date=January 1965|volume=14|issue=3|pages=57–59|doi=10.1103/PhysRevLett.14.57|bibcode = 1965PhRvL..14...57P }}</ref>
* 1965&nbsp;— [[Ezra T. Newman]], E. Couch, K. Chinnapared, A. Exton, A. Prakash, and Robert Torrence solve the Einstein–Maxwell field equations for [[Kerr-Newman metric|charged, rotating]] systems
* 1966&nbsp;— [[Yakov Borisovich Zel'dovich|Yakov Zel’dovich]] and [[Igor Dmitriyevich Novikov|Igor Novikov]] propose searching for black hole candidates among binary systems in which one star is optically bright and X-ray dark and the other optically dark but X-ray bright (the black hole candidate)<ref name="Thorne" />
* 1967&nbsp;— [[Jocelyn Bell]] discovers and analyzes the first radio [[pulsar]], direct evidence for a [[neutron star]]<ref>{{cite journal |last1=Ferrarese |first1=Laura |last2=Ford |first2=Holland |title=Supermassive Black Holes in Galactic Nuclei: Past, Present and Future Research |journal=Space Science Reviews |date=February 2005 |volume=116 |issue=3–4 |pages=523–624 |quote=it is fair to say that the single most influential event contributing to the acceptance of black holes was the 1967 discovery of pulsars by graduate student Jocelyn Bell. The clear evidence of the existence of neutron stars – which had been viewed with much skepticism until then – combined with the presence of a critical mass above which stability cannot be achieved, made the existence of stellar-mass black holes inescapable.|doi=10.1007/s11214-005-3947-6 |bibcode=2005SSRv..116..523F |arxiv=astro-ph/0411247 |s2cid=119091861 }}</ref>
* 1967&nbsp;— [[Werner Israel]] presents the proof of the [[no-hair theorem]] at [[King's College London]]<ref>{{cite journal |last=Israel |first=Werner |journal=Phys. Rev. |volume=164 |pages=1776–1779 |date=1967 |doi=10.1103/PhysRev.164.1776 |title=Event Horizons in Static Vacuum Space-Times |issue=5 |bibcode=1967PhRv..164.1776I }}</ref>
* 1967&nbsp;— [[John Archibald Wheeler|John Wheeler]] introduces the term "black hole" in his lecture to the [[American Association for the Advancement of Science]]<ref name="Thorne" />
* 1968&nbsp;— [[Brandon Carter]] uses [[Hamilton–Jacobi theory]] to derive first-order equations of motion for a charged [[Subatomic particle|particle]] moving in the external fields of a Kerr–Newman black hole
* 1969&nbsp;— [[Roger Penrose]] discusses the [[Penrose process]] for the extraction of the [[Spin (physics)|spin]] [[energy]] from a Kerr black hole<ref>{{Cite journal |last1=Penrose |first1=R. |author-link=Roger Penrose |last2=Floyd |first2=R. M. |date=February 1971 |title=Extraction of Rotational Energy from a Black Hole |journal=Nature Physical Science |language=en |volume=229 |issue=6 |pages=177–179 |doi=10.1038/physci229177a0 |bibcode=1971NPhS..229..177P |issn=0300-8746}}</ref><ref>{{Cite book |last1=Misner |first1=Charles W. |author-link=Charles W. Misner |title=Gravitation |title-link=Gravitation (book) |last2=Thorne |first2=Kip S. |author-link2=Kip Thorne |last3=Wheeler |first3=John Archibald |author-link3=John Archibald Wheeler |date=1973 |publisher=W. H. Freeman |isbn=978-0-7167-0334-1 |location=San Francisco}}Misner, Thorne, and Wheeler, ''[[Gravitation (book)|Gravitation]]'', Freeman and Company, 1973.</ref><ref>{{Cite journal|last=Williams |first=R. K. |date=1995 |title=Extracting X rays, Ύ rays, and relativistic e<sup>−</sup>e<sup>+</sup> pairs from supermassive Kerr black holes using the Penrose mechanism |journal=Physical Review D |volume=51 |issue=10 |pages=5387–5427 |doi=10.1103/PhysRevD.51.5387 |bibcode = 1995PhRvD..51.5387W |pmid=10018300}}</ref>
* 1969&nbsp;— Roger Penrose proposes the [[cosmic censorship hypothesis]]<ref>{{Cite journal |last=Penrose |first=Roger |year=1969 |title=Gravitational Collapse: the Role of General Relativity |journal=[[Nuovo Cimento]] |series=Rivista Serie |volume=1 |pages=252 |bibcode=1969NCimR...1..252P}}</ref>

=== After 1960s ===
* 1972&nbsp;— Identification of [[Cygnus X-1]]/HDE 226868 from dynamic observations as the first binary with a stellar black hole candidate<ref name=aaa305_871>{{cite journal | last=Bombaci | first=I. | title=The maximum mass of a neutron star | journal=Astronomy and Astrophysics | date=1996 | volume=305 | pages=871–877 | bibcode=1996A&A...305..871B | arxiv=astro-ph/9608059 | doi=10.1086/310296 | s2cid=119085893 }}</ref> 
* 1972&nbsp;— [[Stephen Hawking]] proves that the area of a classical black hole's event horizon cannot decrease{{sfn|White|Gribbin|2002|p=146}}{{sfn|Larsen|2005|p=41}}
* 1972&nbsp;— [[James M. Bardeen|James Bardeen]], Brandon Carter, and [[Stephen Hawking]] propose four laws of black hole [[mechanics]] in analogy with the laws of [[thermodynamics]]
* 1972&nbsp;— [[Jacob Bekenstein]] suggests that black holes have an [[entropy]] [[Proportionality (mathematics)|proportional]] to their surface area due to information loss effects
* 1974&nbsp;— Stephen Hawking applies [[quantum field theory]] to black hole spacetimes and shows that black holes will radiate particles with a [[black-body spectrum]] which can cause black hole evaporation<ref>{{cite Q|Q55872061|doi-access=free}}</ref><ref>{{Cite Q|Q54017915}}</ref>
* 1975&nbsp;— [[James Bardeen]] and Jacobus Petterson show that the swirl of spacetime around a [[rotating black hole|spinning black hole]] can act as a gyroscope stabilizing the orientation of the accretion disc and jets<ref name="Thorne" />
* 1989&nbsp;— Identification of [[microquasar]] [[V404 Cygni]] as a binary black hole candidate system
* 1989&nbsp;- [[Eric Poisson]] and [[Werner Israel]] theorize the concept of mass-inflation, a phenomena in which the curvature and gravitational mass parameter inside a [[Kerr metric|spinning]] or [[Reissner-Nordstrom metric|charged]] black hole grow to infinity as one approaches the [[Cauchy horizon|inner horizon]], causing an infalling observer to experience a singularity at the inner horizon of the black hole.<ref>{{cite journal |last1=Poisson |first1=Eric |last2=Israel |first2=Werner |date=October 1989 |title=Inner-horizon instability and mass inflation in black holes |url=https://journals.aps.org/prl/abstract/10.1103/PhysRevLett.63.1663 |journal=Physical Review Letters |volume=63 |issue=16 |publisher=American Physical Society |doi=10.1103/PhysRevLett.63.1663 |access-date=13 May 2025|url-access=subscription }}</ref>
* 1994&nbsp;— [[Charles Townes]] and colleagues observe ionized [[neon]] gas swirling around the center of our Galaxy at such high velocities that a possible black hole mass at the very center must be approximately equal to that of 3 million suns<ref>{{Cite journal|last1=Genzel|first1=R|last2=Hollenbach|first2=D|last3=Townes|first3=C H|date=1994-05-01|title=The nucleus of our Galaxy|journal=Reports on Progress in Physics|volume=57|issue=5|pages=417–479|doi=10.1088/0034-4885/57/5/001|issn=0034-4885|bibcode=1994RPPh...57..417G|s2cid=250900662}}</ref>

==21st century==
* 2002&nbsp;— Astronomers at the [[Max Planck Institute for Extraterrestrial Physics]] present evidence for the hypothesis that [[Sagittarius A*]] is a [[supermassive black hole]] at the center of the [[Milky Way galaxy]]
* 2002&nbsp;— Physicists at [[Ohio State University|The Ohio State University]] publish [[Fuzzball (string theory)|fuzzball theory]], which is a quantum description of black holes positing that they are extended objects composed of [[Superstring theory|strings]] and don't have [[Gravitational singularity|singularities]].
* 2002&nbsp;— [[NASA]]'s [[Chandra X-ray Observatory]] identifies double galactic black holes system in merging [[galaxy|galaxies]] [[NGC 6240]]
* 2004&nbsp;— Further observations by a team from [[UCLA]] present even stronger evidence supporting [[Sagittarius A*]] as a black hole
* 2006&nbsp;— The [[Event Horizon Telescope]] begins capturing data
* 2012&nbsp;— First visual evidence of black-holes: [[Suvi Gezari]]'s team in [[Johns Hopkins University]], using the Hawaiian telescope [[Pan-STARRS 1]], publish images of a [[supermassive black hole]] 2.7 million light-years away swallowing a [[red giant]]<ref>[http://www.scientificamerican.com/article.cfm?id=black-hole-swallows-star] Scientific American – Big Gulp: Flaring Galaxy Marks the Messy Demise of a Star in a Supermassive Black Hole</ref>
* 2015&nbsp;— [[LIGO Scientific Collaboration]] detects the distinctive [[GW150914|gravitational waveforms]] from a [[binary black hole]] merging into a final [[black hole]], yielding the basic parameters (e.g., distance, mass, and spin) of the three spinning black holes involved
* 2019&nbsp;— [[Event Horizon Telescope]] collaboration releases the first direct photo of a black hole, the supermassive [[M87*]] at the core of the [[Messier 87]] galaxy

== References ==
{{reflist}}

==See also==
* [[Timeline of gravitational physics and relativity]]
* [[Schwarzschild radius]]
{{Black holes}}

[[Category:Black holes]]
[[Category:Astronomy timelines|Black hole physics]]
[[Category:Physics timelines|Black hole physics]]