Timeline of black hole physics

The following timeline outlines notable discoveries in the study of black holes in physics, beginning in the 18th century and continuing to modern observations. ^{[1] [2]}

Pre-20th century

• 1640 — Ismaël Bullialdus suggests an inverse-square gravitational force law
• 1676 — Ole Rømer demonstrates that light has a finite speed ^[3]
• 1684 — Isaac Newton writes down his inverse-square law of universal gravitation ^[4]
• 1758 — 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 white holes , could exist. ^[5]
• 1784 — John Michell discusses classical bodies which have escape velocities greater than the speed of light ^[6]
• 1795 — Pierre Laplace discusses classical bodies which have escape velocities greater than the speed of light ^{[7] [8]}
• 1798 — Henry Cavendish measures the gravitational constant G ^{[9] [10]}
• 1876 — William Kingdon Clifford suggests that the motion of matter may be due to changes in the geometry of space

20th century

Before 1960s

• 1909 — Albert Einstein, together with Marcel Grossmann, starts to develop a theory which would bind metric tensor g_ik, which defines a space geometry, with a source of gravity, that is with mass
• 1910 — Hans Reissner and Gunnar Nordström define Reissner–Nordström singularity, Hermann Weyl solves special case for a point-body source
• 1915 — Albert Einstein presents (David Hilbert presented this independently five days earlier in Göttingen) the complete Einstein field equations at the Prussian Academy meeting in Berlin on 25 November 1915 ^[11]
• 1916 — Karl Schwarzschild solves the Einstein vacuum field equations for uncharged spherically symmetric non-rotating systems ^[12]
• 1917 — Paul Ehrenfest gives conditional principle a three-dimensional space
• 1918 — Hans Reissner ^[13] and Gunnar Nordström ^[14] 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 David Birkhoff proves that the Schwarzschild spacetime geometry is the unique spherically symmetric solution of the Einstein vacuum field equations
• 1931 — 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 — Robert Oppenheimer and Hartland Snyder calculate the gravitational collapse of a pressure-free homogeneous fluid sphere into a black hole ^[15]
• 1939 - Using the work of Richard Chace Tolman, Robert Oppenheimer and George Volkoff calculate the upper mass limit of a cold, non-rotating neutron star to be approximately 0.7 solar masses. ^{[16] [17]}
• 1958 — David Finkelstein theorises that the Schwarzschild radius is a causality barrier: an event horizon of a black hole ^[18]

1960s

• 1963 — Roy Kerr solves the Einstein vacuum field equations for uncharged symmetric rotating systems, deriving the Kerr metric for a rotating black hole ^{[19] [20] : 69–81}
• 1963 — Maarten Schmidt discovers and analyzes the first quasar, 3C 273, as a highly red-shifted active galactic nucleus, a billion light years away ^[21]
• 1964 — 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 quasars ^[11]
• 1964 — Hong-Yee Chiu coins the word quasar for a 'quasi-stellar radio source' in his article in Physics Today ^{[22] [23]}
• 1964 — The first recorded use of the term "black hole" in writing, by journalist Ann Ewing ^[24]
• 1965 — Roger Penrose proves that an imploding star will necessarily produce a singularity once it has formed an event horizon ^[25]
• 1965 — Ezra T. Newman, E. Couch, K. Chinnapared, A. Exton, A. Prakash, and Robert Torrence solve the Einstein–Maxwell field equations for charged, rotating systems
• 1966 — Yakov Zel’dovich and 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) ^[11]
• 1967 — Jocelyn Bell discovers and analyzes the first radio pulsar, direct evidence for a neutron star ^[26]
• 1967 — Werner Israel presents the proof of the no-hair theorem at King's College London ^[27]
• 1967 — John Wheeler introduces the term "black hole" in his lecture to the American Association for the Advancement of Science ^[11]
• 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 spin energy from a Kerr black hole ^{[28] [29] [30]}
• 1969 — Roger Penrose proposes the cosmic censorship hypothesis ^[31]

After 1960s

• 1972 — Identification of Cygnus X-1/HDE 226868 from dynamic observations as the first binary with a stellar black hole candidate ^[32]
• 1972 — Stephen Hawking proves that the area of a classical black hole's event horizon cannot decrease ^{[33] [34]}
• 1972 — James Bardeen, Brandon Carter, and Stephen Hawking propose four laws of black hole mechanics in analogy with the laws of thermodynamics
• 1972 — Jacob Bekenstein suggests that black holes have an entropy proportional to their surface area due to information loss effects
• 1974 — 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 ^{[35] [36]}
• 1975 — James Bardeen and Jacobus Petterson show that the swirl of spacetime around a spinning black hole can act as a gyroscope stabilizing the orientation of the accretion disc and jets ^[11]
• 1989 — Identification of microquasar V404 Cygni as a binary black hole candidate system
• 1989 - Eric Poisson and Werner Israel theorize the concept of mass-inflation, a phenomena in which the curvature and gravitational mass parameter inside a spinning or charged black hole grow to infinity as one approaches the inner horizon, causing an infalling observer to experience a singularity at the inner horizon of the black hole. ^[37]
• 1994 — 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 ^[38]

21st century

• 2002 — 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. ^[39]
• 2002 — Physicists at The Ohio State University publish fuzzball theory, which is a quantum description of black holes positing that they are extended objects composed of strings and don't have singularities. ^[40]
• 2002 — NASA's Chandra X-ray Observatory identifies double galactic black holes system in merging galaxies NGC 6240. ^[41]
• 2004 — Further observations by a team from UCLA present even stronger evidence supporting Sagittarius A* as a black hole. ^[42]
• 2006 — The Event Horizon Telescope begins capturing data
• 2012 — 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 ^[43]
• 2015 — LIGO Scientific Collaboration detects the distinctive 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. ^[44]
• 2019 — Event Horizon Telescope collaboration releases the first direct photo of a black hole, the supermassive M87* at the core of the Messier 87 galaxy. ^[45]

References

1. Thorne, Kip S. (1994). Black holes and time warps: Einstein's outrageous legacy. The Commonwealth Fund Book Program. New York: W.W. Norton. ISBN   978-0-393-03505-6.
2. Begelman, Mitchell; Rees, Martin; Wheeler, J. Craig (1997-06-01). "Gravity's Fatal Attraction: Black Holes in the Universe" . American Journal of Physics. 65 (6): 580–581. doi:10.1119/1.18608. ISSN   0002-9505.
3. P. 328 of Romer, M.; Cohen, I Bernard (1940). "Roemer and the First Determination of the Velocity of Light (1676)". Isis. 31 (2): 327–379. doi:10.1086/347594. hdl: 2027/uc1.b4375710 . ISSN   0021-1753. JSTOR   225757. S2CID   145428377 . Retrieved 2023-03-24.
4. More, Louis Trenchard (1934). Isaac Newton: A Biography. Dover Publications. p. 327.
5. Rowlinson, J.S. (2002). Cohesion: A Scientific History of Intermolecular Forces. Cambridge University Press. ISBN   9781139435888.
6. Platts-Mills, Ben (2 July 2024). "The forgotten priest who predicted black holes – in 1783". BBC . Retrieved 2025-01-03.
7. Laplace, P.-S. (1799). Allgemeine geographische Ephemeriden herausgegeben von F. von Zach . IV. Band, I. Stück, I. Abhandlung, Weimar; translation in English: Hawking, Stephen W.; Ellis, George F.R. (1973). The Large Scale Structure of Space-Time. Cambridge University Press. pp. 365ff. ISBN   978-0-521-09906-6.
8. Colin Montgomery, Wayne Orchiston and Ian Whittingham, "Michell, Laplace and the origin of the Black Hole Concept" Archived 2 May 2014 at the Wayback Machine , Journal of Astronomical History and Heritage, 12(2), 90–96 (2009).
9. Poynting 1911, p. 385. sfn error: no target: CITEREFPoynting1911 (help)
10. '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).
11. Thorne, Kip S. (1994). Black holes and time warps : Einstein's outrageous legacy . New York. ISBN   0393035050. OCLC   28147932.
12. Levy, Adam (January 11, 2021). "How black holes morphed from theory to reality" . Knowable Magazine. doi: 10.1146/knowable-010921-1 . S2CID   250662997 . Retrieved 25 March 2022.
13. Reissner, H. (1916). "Über die Eigengravitation des elektrischen Feldes nach der Einsteinschen Theorie". Annalen der Physik. 355 (9): 106–120. Bibcode:1916AnP...355..106R. doi:10.1002/andp.19163550905. ISSN   0003-3804.
14. Nordström, G. (1918). "On the Energy of the Gravitational Field in Einstein's Theory". Koninklijke Nederlandsche Akademie van Wetenschappen Proceedings. 20 (2): 1238–1245. Bibcode:1918KNAB...20.1238N.
15. Oppenheimer, J. R.; Snyder, H. (1 September 1939). "On Continued Gravitational Contraction". Physical Review. 56 (5). American Physical Society (APS): 455–459. Bibcode:1939PhRv...56..455O. doi: 10.1103/physrev.56.455 . ISSN   0031-899X.
16. Tolman, R. C. (1939). "Static Solutions of Einstein's Field Equations for Spheres of Fluid" . Physical Review . 55 (4): 364–373. Bibcode:1939PhRv...55..364T. doi:10.1103/PhysRev.55.364.
17. Oppenheimer, J. R.; Volkoff, G. M. (1939). "On Massive Neutron Cores". Physical Review . 55 (4): 374–381. Bibcode:1939PhRv...55..374O. doi:10.1103/PhysRev.55.374.
18. Finkelstein, David (1958). "Past-future asymmetry of the gravitational field of a point particle". Physical Review. 110 (4): 965–967. Bibcode:1958PhRv..110..965F. doi:10.1103/PhysRev.110.965.
19. Kerr, Roy P. (1963). "Gravitational Field of a Spinning Mass as an Example of Algebraically Special Metrics". Physical Review Letters. 11 (5): 237–238. Bibcode:1963PhRvL..11..237K. doi:10.1103/PhysRevLett.11.237.
20. 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
21. Risen, Clay (22 September 2022). "Maarten Schmidt, First Astronomer to Identify a Quasar, Dies at 92". The New York Times . Retrieved 22 September 2022.
22. Chiu, Hong-Yee (May 1964). "Gravitational collapse". Physics Today. 17 (5): 21–34. Bibcode:1964PhT....17e..21C. doi: 10.1063/1.3051610 . 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.
23. "Hong-Yee Chiu (b. 1932)". Smithsonian Institution Archives, Accession 90-105, Science Service Records, Image No. SIA2008-0238. Retrieved April 6, 2013. Summary: Chinese-American astrophysicist Hong-Yee Chiu (b. 1932) is credited with coining the term "quasar" in 1964.
24. Bartusiak, Marcia (2015). Black Hole: How an Idea Abandoned by Newtonians, Hated by Einstein, and Gambled On by Hawking Became Loved. New Haven, CT: Yale University Press. ISBN   978-0-300-21363-8.
25. Penrose, Roger (January 1965). "Gravitational Collapse and Space-Time Singularities". Physical Review Letters. 14 (3): 57–59. Bibcode:1965PhRvL..14...57P. doi:10.1103/PhysRevLett.14.57.
26. Ferrarese, Laura; Ford, Holland (February 2005). "Supermassive Black Holes in Galactic Nuclei: Past, Present and Future Research". Space Science Reviews. 116 (3–4): 523–624. arXiv: astro-ph/0411247 . Bibcode:2005SSRv..116..523F. doi:10.1007/s11214-005-3947-6. S2CID   119091861. 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.
27. Israel, Werner (1967). "Event Horizons in Static Vacuum Space-Times". Phys. Rev. 164 (5): 1776–1779. Bibcode:1967PhRv..164.1776I. doi:10.1103/PhysRev.164.1776.
28. Penrose, R.; Floyd, R. M. (February 1971). "Extraction of Rotational Energy from a Black Hole". Nature Physical Science. 229 (6): 177–179. Bibcode:1971NPhS..229..177P. doi:10.1038/physci229177a0. ISSN   0300-8746.
29. Misner, Charles W.; Thorne, Kip S.; Wheeler, John Archibald (1973). Gravitation. San Francisco: W. H. Freeman. ISBN   978-0-7167-0334-1.Misner, Thorne, and Wheeler, Gravitation , Freeman and Company, 1973.
30. Williams, R. K. (1995). "Extracting X rays, Ύ rays, and relativistic e⁻e⁺ pairs from supermassive Kerr black holes using the Penrose mechanism". Physical Review D. 51 (10): 5387–5427. Bibcode:1995PhRvD..51.5387W. doi:10.1103/PhysRevD.51.5387. PMID   10018300.
31. Penrose, Roger (1969). "Gravitational Collapse: the Role of General Relativity". Nuovo Cimento . Rivista Serie. 1: 252. Bibcode:1969NCimR...1..252P.
32. Bombaci, I. (1996). "The maximum mass of a neutron star". Astronomy and Astrophysics. 305: 871–877. arXiv: astro-ph/9608059 . Bibcode:1996A&A...305..871B. doi:10.1086/310296. S2CID   119085893.
33. White & Gribbin 2002, p. 146. sfn error: no target: CITEREFWhiteGribbin2002 (help)
34. Larsen 2005, p. 41. sfn error: no target: CITEREFLarsen2005 (help)
35. S. W. Hawking; R. Penrose (27 January 1970). "The Singularities of Gravitational Collapse and Cosmology". Proceedings of the Royal Society A. 314 (1519): 529–548. Bibcode:1970RSPSA.314..529H. doi: 10.1098/RSPA.1970.0021 . ISSN   1364-5021. S2CID   120208756. Zbl   0954.83012. Wikidata   Q55872061.
36. Stephen Hawking (March 1974). "Black hole explosions?". Nature . 248 (5443): 30–31. Bibcode:1974Natur.248...30H. doi:10.1038/248030A0. ISSN   1476-4687. S2CID   4290107. Zbl   1370.83053. Wikidata   Q54017915.
37. Poisson, Eric; Israel, Werner (October 1989). "Inner-horizon instability and mass inflation in black holes" . Physical Review Letters. 63 (16). American Physical Society: 1663–1666. Bibcode:1989PhRvL..63.1663P. doi:10.1103/PhysRevLett.63.1663. PMID   10040638 . Retrieved 13 May 2025.
38. Genzel, R; Hollenbach, D; Townes, C H (1994-05-01). "The nucleus of our Galaxy". Reports on Progress in Physics. 57 (5): 417–479. Bibcode:1994RPPh...57..417G. doi:10.1088/0034-4885/57/5/001. ISSN   0034-4885. S2CID   250900662.
39. Schödel, R.; Ott, T.; Genzel, R.; Hofmann, R.; Lehnert, M.; Eckart, A.; Mouawad, N.; Alexander, T.; Reid, M. J.; Lenzen, R.; Hartung, M.; Lacombe, F.; Rouan, D.; Gendron, E.; Rousset, G. (2002). "A star in a 15.2-year orbit around the supermassive black hole at the centre of the Milky Way". Nature. 419 (6908): 694–696. arXiv: astro-ph/0210426 . Bibcode:2002Natur.419..694S. doi:10.1038/nature01121. ISSN   1476-4687.
40. Lunin, Oleg; Mathur, Samir D. (2002-02-18). "AdS/CFT duality and the black hole information paradox". Nuclear Physics B. 623 (1): 342–394. arXiv: hep-th/0109154 . Bibcode:2002NuPhB.623..342L. doi:10.1016/S0550-3213(01)00620-4. ISSN   0550-3213.
41. "Chandra :: Photo Album :: NGC 6240 :: April 30, 2013". chandra.harvard.edu. Retrieved 2025-08-28.
42. Ghez, A. M.; Salim, S.; Hornstein, S. D.; Tanner, A.; Lu, J. R.; Morris, M.; Becklin, E. E.; Duchene, G. (2005-02-20). "Stellar Orbits around the Galactic Center Black Hole". The Astrophysical Journal. 620 (2): 744–757. arXiv: astro-ph/0306130 . Bibcode:2005ApJ...620..744G. doi:10.1086/427175. ISSN   0004-637X.
43. Scientific American – Big Gulp: Flaring Galaxy Marks the Messy Demise of a Star in a Supermassive Black Hole
44. LIGO Scientific Collaboration and Virgo Collaboration; Abbott, B. P.; Abbott, R.; Abbott, T. D.; Abernathy, M. R.; Acernese, F.; Ackley, K.; Adams, C.; Adams, T.; Addesso, P.; Adhikari, R. X.; Adya, V. B.; Affeldt, C.; Agathos, M.; Agatsuma, K. (2016-02-11). "Observation of Gravitational Waves from a Binary Black Hole Merger". Physical Review Letters. 116 (6): 061102. arXiv: 1602.03837 . Bibcode:2016PhRvL.116f1102A. doi:10.1103/PhysRevLett.116.061102. PMID   26918975.
45. Akiyama, Kazunori; Alberdi, Antxon; Alef, Walter; Asada, Keiichi; Azulay, Rebecca; Baczko, Anne-Kathrin; Ball, David; Baloković, Mislav; Barrett, John; Bintley, Dan; Blackburn, Lindy; Boland, Wilfred; Bouman, Katherine L.; Bower, Geoffrey C.; Bremer, Michael (2019-04-10). "First M87 Event Horizon Telescope Results. I. The Shadow of the Supermassive Black Hole". The Astrophysical Journal Letters. 875 (1): L1. arXiv: 1906.11238 . Bibcode:2019ApJ...875L...1E. doi: 10.3847/2041-8213/ab0ec7 . ISSN   2041-8205.

See also

• Timeline of gravitational physics and relativity
• Schwarzschild radius