Timeline of gravitational physics and relativity

File:E mc 2 IMG 0859.jpg

Einstein's mass-energy equation in a 1912 manuscript. He originally used <math>L</math> instead of <math>E</math> to denote energy.

Template:General relativity sidebar The following is a timeline of gravitational physics and general relativity.

Before 1500

• 3rd century B.C. – Aristarchus of Samos proposes the heliocentric model.<ref name=":9">Template:Cite book</ref>

1500s

• 1543 – Nicolaus Copernicus publishes On the Revolutions of Heavenly Spheres.<ref name=":9" />
• 1583 – Galileo Galilei deduces the period relationship of a pendulum from observations (according to later biographer).
• 1586 – Simon Stevin demonstrates that two objects of different mass accelerate at the same rate when dropped.<ref>Template:Cite book</ref>
• 1589 – Galileo Galilei describes a hydrostatic balance for measuring specific gravity.
• 1590 – Galileo Galilei formulates modified Aristotelean theory of motion (later retracted) based on density rather than weight of objects.

1600s

File:Principia1846-105.png

Geometric diagram for Newton's proof of Kepler's second law.

• 1602-1608 – Galileo Galilei experiments with pendulum motion and inclined planes; deduces his law of free fall; and discovers that projectiles travel along parabolic trajectories.<ref name=":11">Template:Cite book</ref>
• 1609 – Johannes Kepler announces his first two laws of planetary motion.<ref name=":8">Template:Cite book</ref>
• 1610 – Johannes Kepler states the dark night paradox.<ref>{{#invoke:citation/CS1|citation

|CitationClass=web }}</ref>

• 1610 – Galileo Galilei publishes The Sidereal Messenger, detailing his astronomical discoveries made with a telescope.<ref>Template:Cite book</ref>
• 1619 – Johannes Kepler unveils his third law of planetary motion.<ref name=":8" />
• 1665-66 – Isaac Newton introduces an inverse-square law of universal gravitation uniting terrestrial and celestial theories of motion and uses it to predict the orbit of the Moon and the parabolic arc of projectiles (the latter using his generalization of the binomial theorem).<ref name=":10">Template:Cite book</ref>
• 1676-9 – Ole Rømer makes the first scientific determination of the speed of light.<ref>Template:Cite book</ref>
• 1684 – Isaac Newton proves that planets moving under an inverse-square force law will obey Kepler's laws in a letter to Edmond Halley.<ref name=":10" />
• 1686 – Isaac Newton uses a fixed length pendulum with weights of varying composition to test the weak equivalence principle to 1 part in 1000.<ref name=":7">Template:Cite book</ref><ref>Template:Cite book</ref>
• 1686 – Isaac Newton publishes his Mathematical Principles of Natural Philosophy, where he develops his calculus, states his laws of motion and gravitation, proves the shell theorem, describes his rotating bucket thought experiment, explains the tides, and calculates the figure of the Earth.<ref name=":7" />

1700s

File:Lagrange very massive.svg

Lagrange points

• 1705 – Edmond Halley predicts the return of Halley's comet in 1758,<ref>Template:Cite book</ref> the first use of Newton's laws by someone other than Newton himself.<ref>Template:Cite book</ref>
• 1728 – Isaac Newton posthumously publishes his cannonball thought experiment.<ref name="treatiselat">De mundi systemate, Isaac Newton, London: J. Tonson, J. Osborn, & T. Longman, 1728.</ref><ref name="cohen2004">Template:Cite book</ref>
• 1742 – Colin Maclaurin studies a self-gravitating uniform liquid drop at equilibrium, the Maclaurin spheroid.<ref>Maclaurin, Colin. A Treatise of Fluxions: In Two Books. 1. Vol. 1. Ruddimans, 1742.</ref><ref>Template:Cite book</ref>
• 1740s – Jean le Rond d'Alembert and Leonhard Euler independently examine the precession of the equinoxes and nutation of the Earth. In the process, they develop the dynamics of rigid bodies.<ref name=":16">Template:Cite book</ref>
• 1740s-1750s – Leonhard Euler and Alexis Clairault independently derive the equations of motion for the three-body problem and apply them to the Moon.<ref name=":16" />
• 1755 – Immanuel Kant advances Emanuel Swedenborg's nebular hypothesis on the origin of the Solar System.<ref name="Woolfson1993">Template:Cite journal For details of Kant's position, see Stephen Palmquist, "Kant's Cosmogony Re-Evaluated", Studies in History and Philosophy of Science 18:3 (September 1987), pp.255–269.</ref>
• 1765 – Leonhard Euler discovers the first three Lagrange points.<ref>Template:Cite book (16MB)</ref><ref name="E327">Template:Cite book</ref>
• 1767 – Leonhard Euler solves Euler's restricted three-body problem.<ref name="euler_1760">Euler L, Nov. Comm. Acad. Imp. Petropolitanae, 10, pp. 207–242, 11, pp. 152–184; Mémoires de l'Acad. de Berlin, 11, 228–249.</ref>
• 1772 – Joseph-Louis Lagrange discovers the two remaining Lagrange points.<ref name="gallica.bnf.fr2">Template:Cite book</ref>
• 1770s-1780s – Joseph-Louis Lagrange and Pierre-Simon de Laplace investigate the stability of the Solar System.<ref name=":16" />
• 1780s – Adrien-Marie Legendre and Pierre-Simon de Laplace study the gravitational attraction of spheroids in spherical coordinates and introduce the Legendre polynomials.<ref name=":16" />
• 1796 – Pierre-Simon de Laplace independently introduces the nebular hypothesis.<ref name="Woolfson1993" />
• 1798 – Henry Cavendish tests Newton's law of universal gravitation using a torsion balance, leading to the first accurate value for the gravitational constant and the mean density of the Earth.<ref>Template:Cite journal</ref><ref>Template:Cite journal</ref>

1800s

• 1846 – Urbain Le Verrier and John Couch Adams, studying Uranus' orbit, independently prove that another, farther planet must exist. Neptune was found at the predicted moment and position.
• 1855 – Le Verrier observes a 38 arc-second per century excess precession of Mercury's orbit and attributes it to another planet, inside Mercury's orbit. The planet, called Vulcan, was never found. Le Verrier's figure is revised by Simon Newcomb to 43 arc-second per century in 1882.<ref name=":16" />
• 1876 – William Kingdon Clifford suggests that the motion of matter may be due to changes in the geometry of space.<ref>s:On the Space Theory of Matter</ref>
• 1884 – William Thomson (Lord Kelvin) lectures on the issues with the wave theory of light with regards to the luminiferous ether.<ref name=":15" />
• 1887 – Albert A. Michelson and Edward W. Morley in their famous experiment do not detect the ether drift.<ref>Template:Cite journal</ref><ref>Template:Cite book</ref>
• 1889 – Loránd Eötvös uses a torsion balance to test the weak equivalence principle to 1 part in one billion.<ref>{{#invoke:citation/CS1|citation

|CitationClass=web }}</ref>

• 1887 – George Francis FitzGerald explains his hypothesis that the Michelson-Morley interferometer contracts in the direction of motion through the luminiferous ether to Oliver Lodge.<ref name=":15">Template:Cite journal</ref>
• 1893 – Ernst Mach states Mach's principle, the first constructive critique of the idea of Newtonian absolute space.
• 1897 – Henri Poincaré questions whether absolute space, absolute time, and Euclidean geometry are applicable to physics.<ref>Template:Cite book</ref>

1900s

File:USS Enterprise (CVAN-65), USS Long Beach (CGN-9) and USS Bainbridge (DLGN-25) underway in the Mediterranean Sea during Operation Sea Orbit, in 1964.jpg

The U.S. Navy's nuclear-powered Task Force 1 underway for Operation Sea Orbit in the Mediterranean, 1964.

• 1902 – Paul Gerber explains the movement of the perihelion of Mercury using finite speed of gravity.<ref>Template:Cite journal (Originally published in Programmabhandlung des städtischen Realgymnasiums zu Stargard i. Pomm., 1902)</ref> His formula, at least approximately, matches the later model from Einstein's general relativity, but Gerber's theory was incorrect.
• 1902 – Henri Poincaré questions the concept of simultaneity in his book, Science and Hypothesis.<ref name=":12">Template:Cite book</ref><ref>Template:Cite book</ref>
• 1904 – Hendrik Antoon Lorentz publishes the Lorentz transformations,<ref>Template:Cite journal</ref> so named by Henri Poincaré.<ref name=":15" />
• 1902 – Henri Poincaré shows that the Lorentz transformations form a mathematical group, called the Lorentz group, and derives the relativistic formula for adding velocities.<ref name=":15" />
• 1905 – Albert Einstein completes his special theory of relativity<ref>Template:Cite journal</ref><ref name=":82">Template:Cite book</ref> and examines relativistic aberration and the transverse Doppler effect.<ref name=":15" />
• 1905 – Albert Einstein discovers the equivalence of mass and energy,<ref>Template:Cite journal</ref> <math>E = mc^2</math> in modern form.<ref>Template:Cite journal</ref><ref>Template:Cite journal</ref><ref name=":12" />
• 1906 – Max Planck coins the term Relativtheorie. Albert Einstein later uses the term Relativitätstheorie in a conversation with Paul Ehrenfest. He originally prefers calling it Invariance Theory.<ref>Template:Cite book</ref>
• 1906 – Max Planck formulates a variational principle for special relativity.<ref>Template:Cite book</ref>
• 1907 – Albert Einstein introduces the principle of equivalence of gravitational and inertial mass and uses it to predict gravitational lensing and gravitational redshift,<ref>Template:Cite journal</ref><ref name=":22">Template:Cite book</ref> historically known as the Einstein shift.<ref name=":4">Template:Cite journal</ref>
• 1907-8 – Hermann Minkowski introduces the Minkowski spacetime and the notion of tensors to relativity. His paper was published posthumously.<ref>Template:Cite journal</ref><ref>Template:Cite journal</ref><ref>Template:Cite book</ref>
• 1909 – Max Born proposes his notion of rigidity.<ref>Template:Cite journal</ref><ref>Template:Cite journal</ref>
• 1909 – Paul Ehrenfest states the Ehrenfest paradox.<ref>Template:Cite journal</ref><ref>Template:Cite journal</ref>

1910s

File:Einstein's argument that falling light acquires energy.svg

Einstein's 1911 argument for gravitational redshift

• 1911 – Max von Laue publishes the first textbook on special relativity.<ref name=":14">Template:Cite journal</ref>
• 1911 – Albert Einstein explains the need to replace both special relativity and Newton's theory of gravity; he realizes that the principle of equivalence only holds locally, not globally.<ref>Template:Cite journal</ref>
• 1912 – Friedrich Kottler applies the notion of tensors to curved spacetime.<ref>Template:Cite journal</ref><ref name=":14" />
• 1915-16 – Albert Einstein completes his general theory of relativity.<ref>Template:Cite journal</ref><ref name=":13">Template:Cite journal</ref> He explains the perihelion of Mercury and calculates gravitational lensing correctly and introduces the post-Newtonian approximation.<ref>Template:Cite journal</ref><ref>Template:Cite journal</ref>
• 1915 – David Hilbert independently introduces the Einstein-Hilbert action.<ref>Template:Citation</ref><ref name=":13" /> Hilbert also recognizes the connection between the Einstein equations and the Gauss-Bonnet theorem.<ref>Template:Cite book</ref>
• 1916 – Karl Schwarzschild publishes the Schwarzschild metric about a month after Einstein published his general theory of relativity.<ref>Template:Cite journal</ref><ref>Template:Cite journal</ref> This was the first solution to the Einstein field equations other than the trivial flat space solution.<ref name="Levy">Template:Cite journal</ref><ref name="Eisenstaedt, 1989">Eisenstaedt, "The Early Interpretation of the Schwarzschild Solution," in D. Howard and J. Stachel (eds), Einstein and the History of General Relativity: Einstein Studies, Vol. 1, pp. 213-234. Boston: Birkhauser, 1989.</ref><ref>Template:Cite book</ref>
• 1916 – Albert Einstein predicts gravitational waves.<ref>Template:Cite journal</ref>
• 1916 – Willem de Sitter predicts the geodetic effect.<ref>Template:Cite journal</ref>
• 1917 – Albert Einstein applies his field equations to the entire Universe.<ref>Template:Cite journal</ref> Physical cosmology is born.<ref name=":22" />
• 1916-20 – Arthur Eddington studies the internal constitution of the stars.<ref name="eddington">The Internal Constitution of the Stars A. S. Eddington The Scientific Monthly Vol. 11, No. 4 (Oct., 1920), pp. 297–303 Template:JSTOR</ref><ref name="eddington2">Template:Cite journal</ref>
• 1918 – Albert Einstein derives the quadrupole formula for gravitational radiation.<ref>Template:Cite journal</ref><ref>Template:Cite journal</ref>
• 1918 – Emmy Noether publishes Noether's theorem and resolves the issue of local energy conservation in general relativity.<ref>Template:Cite journal</ref><ref>Template:Cite journal</ref>
• 1918 – Josef Lense and Hans Thirring find the gravitomagnetic frame-dragging of gyroscopes in the equations of general relativity.<ref>Template:Cite journal [On the Effect of Rotating Distant Masses in Einstein's Theory of Gravitation]</ref><ref>Template:Cite journal [Correction to my paper "On the Effect of Rotating Distant Masses in Einstein's Theory of Gravitation"]</ref><ref>Template:Cite journal [On the Influence of the Proper Rotation of Central Bodies on the Motions of Planets and Moons According to Einstein's Theory of Gravitation]</ref>
• 1919 – Arthur Eddington leads a solar eclipse expedition which detects gravitational deflection of light by the Sun,<ref name="Eddington1920">Template:Cite journal</ref> which, despite opinion to the contrary, survives modern scrutiny.<ref name="PhysToday">Template:Cite journal</ref> Other teams fail for reasons of war and politics.<ref>Template:Cite news</ref>

1920s

• 1921 – Theodor Kaluza demonstrates that a five-dimensional version of Einstein's equations unifies gravitation and electromagnetism.<ref name="kal">Template:Cite journal</ref> This idea is later extended by Oskar Klein.<ref>Template:Cite book</ref>
• 1922 – Alexander Friedmann derives the Friedmann equations.<ref name="af1922">Template:Cite journal Translated in: Template:Cite journal</ref><ref name=":22" />
• 1922 – Enrico Fermi introduces the Fermi coordinates.<ref>Template:Cite journal</ref><ref>Template:Cite book</ref> This is developed further in 1932 by Arthur Walker into the Fermi-Walker transport.<ref name=":02" />
• 1923 – George David Birkhoff proves Birkhoff's theorem on the uniqueness of the Schwarzschild solution.
• 1924 – Arthur Eddington calculates the Eddington limit.<ref name="eddington3">Template:Cite journal</ref>
• 1924 – Cornelius Lanczos discovers the van Stockum dust,<ref>Template:Cite journal</ref> later rediscovered by Willem Jacob van Stockum in 1938.<ref>Template:Cite journal</ref>
• 1925 – Walter Adams measures the gravitational redshift of the light emitted by the companion of Sirius B, a white dwarf.<ref>Template:Cite journal</ref>
• 1927 – Georges Lemaître publishes his hypothesis of the primeval atom.<ref>{{#invoke:citation/CS1|citation

|CitationClass=web }}</ref><ref name=":22" />

• 1929 – Edwin Hubble published the law later named for him.<ref name="hubble">Template:Cite journal</ref>

1930s

File:Einstein cross (cropped).jpg

The Einstein Cross is an example of gravitational lensing at work. This one was discovered in 1985.<ref>Template:Cite journal</ref>

• 1931 – Subrahmanyan Chandrasekhar studies the stability of white dwarfs.<ref name="chandra3">Template:Cite journal</ref><ref name="chandra4">Template:Cite journal</ref>
• 1931 – Georges Lemaître and Arthur Eddington predict the expansion of the Universe.<ref>Template:Cite journal</ref><ref>Template:Cite journal</ref>
• 1931 – Albert Einstein introduces his cosmological constant.<ref>Template:Cite journal</ref>
• 1932 – Albert Einstein and Willem de Sitter propose the Einstein-de Sitter cosmological model.<ref>Template:Cite journal</ref>
• 1932 – John Cockcroft and Ernest Walton verify Einstein's mass-energy equation by an experiment artificially transmuting lithium into helium.<ref>Template:Cite journal</ref><ref>Template:Cite journal</ref>
• 1934 – Dmitry Blokhintsev and F. M. Gal'perin coin the term 'graviton'.<ref>Template:Cite journal</ref> Paul Dirac reintroduces it in 1959.<ref>Template:Cite book</ref><ref name="Debnath">Template:Cite journal</ref>
• 1934 – Walter Baade and Fritz Zwicky predict the existence of neutron stars.<ref>Template:Cite journal</ref> Although their details are wrong, their basic idea is now accepted.<ref>Template:Cite news</ref>
• 1935 – Albert Einstein and Nathan Rosen derive the Einstein-Rosen bridge, the first wormhole solution.<ref name="ER">A. Einstein and N. Rosen, "The Particle Problem in the General Theory of Relativity," Phys. Rev. 48(73) (1935).</ref>
• 1935 – Howard Robertson and Arthur Walker obtain the Robertson-Walker metric.<ref name=":02">Template:Cite journal</ref>
• 1936 – Albert Einstein predicts that a gravitational lens brightens the light coming from a distant object to the observer.<ref>Template:Cite journal</ref>
• 1937 – Fritz Zwicky states that galaxies could act as gravitational lenses.<ref>Template:Cite journal</ref>
• 1937 – Albert Einstein and Nathan Rosen obtain the Einstein-Rosen metric, the first exact solution describing gravitational waves.<ref>Template:Cite journal</ref>
• 1938 – Albert Einstein, Leopold Infeld, and Banesh Hoffmann obtain the Einstein-Infeld-Hoffmann equations of motion.<ref>Template:Cite journal</ref>
• 1939 – Hans Bethe shows that nuclear fusion is responsible for energy production inside stars,<ref name="frs">Template:Cite journal</ref> building upon the Kelvin–Helmholtz mechanism.
• 1939 – Richard Tolman solves the Einstein field equations in the case of a spherical fluid drop.<ref>Template:Cite journal</ref><ref name=":6" />
• 1939 – Robert Serber, George Volkoff, Richard Tolman, and J. Robert Oppenheimer study the stability of neutron stars, obtaining the Tolman–Oppenheimer–Volkoff limit.<ref>Template:Cite journal</ref><ref>Template:Cite journal</ref><ref name=":6">Template:Cite book</ref>
• 1939 – J. Robert Oppenheimer and Hartland Snyder publish the Oppenheimer-Snyder model for the continued gravitational contraction of a star.<ref>Template:Cite journal</ref><ref name=":6" /><ref>Template:Cite news</ref>

1940s

• 1948 – Ralph Alpher and Robert Herman predict the cosmic microwave background.<ref>Template:Cite journal</ref><ref>Template:Cite journal</ref>
• 1949 – Cornelius Lanczos introduces the Lanczos potential for the Weyl tensor.<ref name="Lanczos1949">Template:Cite journal</ref>
• 1949 – Kurt Gödel discovers Gödel's solution.<ref>Gödel, K., "An Example of a New Type of Cosmological Solutions of Einstein's Field Equations of Gravitation", Rev. Mod. Phys. 21, 447, published July 1, 1949.</ref>

1950s

• 1953 – P. C. Vaidya Newtonian time in general relativity, Nature, 171, p260.
• 1954 – Suraj Gupta sketches how to derive the equations of general relativity from quantum field theory for a massless spin-2 particle (the graviton).<ref name="PPS">Template:Cite journal</ref> His procedure was later carried out by Stanley Deser in 1970.<ref>Template:Cite journal</ref><ref name="Preskill" />
• 1955-56 – Robert Kraichnan shows that under the appropriate assumptions, Einstein's field equations of gravitation arise from the quantum field theory of a massless spin-2 particle coupled to the stress-energy tensor.<ref>Template:Cite journal</ref><ref>Template:Cite journal</ref> This follows from his unpublished work as an undergraduate in 1947.<ref name="Preskill" />
• 1956 – Bruno Berlotti develops the post-Minkowskian expansion.<ref>Template:Cite journal</ref>
• 1956 – John Lighton Synge publishes the first relativity text emphasizing spacetime diagrams and geometrical methods.
• 1957 – Felix A. E. Pirani uses Petrov classification to understand gravitational radiation.
• 1957 – Richard Feynman introduces his sticky bead argument.<ref name="Preskill">Preskill, John and Kip S. Thorne. Foreword to Feynman Lectures On Gravitation. Feynman et al. (Westview Press; 1st ed. (June 20, 2002). PDF link</ref><ref name="Feynman">Template:Cite book</ref> He later derives the quadrupole formula in a letter to Victor Weisskopf (1961).<ref name="Preskill" />
• 1957-8 – John Wheeler discusses the breakdown of classical general relativity near singularities and the need for quantum gravity.<ref name=":22" />
• 1958 – David Finkelstein presents a new coordinate system that eliminates the Schwarzschild radius as a singularity.<ref>Template:Cite journal</ref>
• 1959 – Robert Pound and Glen Rebka propose the Pound–Rebka experiment, first precision test of gravitational redshift. The experiment relies on the Mössbauer effect.<ref>Template:Cite journal</ref>
• 1959 – Lluís Bel introduces Bel–Robinson tensor and the Bel decomposition of the Riemann tensor.
• 1959 – Arthur Komar introduces the Komar mass.
• 1959 – Richard Arnowitt, Stanley Deser and Charles W. Misner developed ADM formalism.

1960s

• 1960 – Martin Kruskal and George Szekeres independently introduce the Kruskal–Szekeres coordinates for the Schwarzschild vacuum.<ref>Template:Cite journal</ref><ref name="rsbm">Template:Cite journal</ref>
• 1960 – John Graves and Dieter Brill study the causal structure of an electrically charged black hole.<ref>Template:Cite journal</ref>
• 1960 – Thomas Matthews and Allan R. Sandage associate 3C 48 with a point-like optical image, show radio source can be at most 15 light minutes in diameter,
• 1960 – Ivor M. Robinson and Andrzej Trautman discover the Robinson-Trautman null dust solution<ref name="RobTrautmanPhysRevL1960_fixthis">Template:Cite journal</ref>
• 1960 – Robert Pound and Glen Rebka test the gravitational redshift predicted by the equivalence principle to approximately 1%.<ref>Template:Cite journal</ref>
• 1961 –Tullio Regge introduces the Regge calculus.<ref>Template:Cite journal Available (subscribers only) at Il Nuovo Cimento</ref>
• 1961 – Carl H. Brans and Robert H. Dicke introduce Brans–Dicke theory, the first viable alternative theory with a clear physical motivation.<ref>Template:Cite journal</ref>
• 1961 – Pascual Jordan and Jürgen Ehlers develop the kinematic decomposition of a timelike congruence,
• 1961 – Robert Dicke, Peter Roll, and R. Krotkov refine the Eötvös experiment to an accuracy of 10⁻¹¹.<ref>Template:Cite journal</ref><ref>Template:Cite journal</ref>
• 1962 – John Wheeler and Robert Fuller show that the Einstein-Rosen bridge is unstable.<ref>Template:Cite journal</ref>
• 1962 – Roger Penrose and Ezra T. Newman introduce the Newman–Penrose formalism.
• 1962 – Ehlers and Wolfgang Kundt classify the symmetries of Pp-wave spacetimes.
• 1962 –Joshua Goldberg and Rainer K. Sachs prove the Goldberg–Sachs theorem.<ref name="original_paper">Template:Cite journal; originally published in Acta Phys. Pol. 22, 13–23 (1962).</ref>
• 1962 – Ehlers introduces Ehlers transformations, a new solution generating method,
• 1962 – Richard Arnowitt, Stanley Deser, and Charles W. Misner introduce the ADM reformulation and global hyperbolicity,
• 1962 – Istvan Ozsvath and Englbert Schücking rediscover the circularly polarized monochromomatic gravitational wave.
• 1962 – Hans Adolph Buchdahl discovers Buchdahl's theorem.
• 1962 – Hermann Bondi introduces Bondi mass.
• 1962 – Hermann Bondi, M. G. van der Burg, A. W. Metzner, and Rainer K. Sachs introduce the asymptotic symmetry group of asymptotically flat, Lorentzian spacetimes at null (i.e., light-like) infinity.
• 1963 – Roy Kerr discovers the Kerr vacuum solution of Einstein's field equations,<ref name="kerr_1963">Template:Cite journal</ref>
• 1963 – Redshifts of 3C 273 and other quasars show they are very distant; hence very luminous,
• 1963 – Newman, T. Unti and L.A. Tamburino introduce the NUT vacuum solution,
• 1963 – Roger Penrose introduces Penrose diagrams and Penrose limits.<ref>Template:Cite journal</ref>
• 1963 – Maarten Schmidt and Jesse Greenstein discover quasi-stellar objects, later shown to be moving away from Earth due to the expansion of the Universe.<ref name=":22" />
• 1963 – First Texas Symposium on Relativistic Astrophysics held in Dallas, 16–18 December.<ref name=":22" />
• 1964 – Steven Weinberg shows that a quantum field theory of interacting massless spin-2 particles is Lorentz invariant only if it satisfies the principle of equivalence.<ref>Template:Cite journal</ref><ref>Template:Cite journal</ref><ref name="Preskill" />
• 1964 – Subrahmanyan Chandrasekhar determines a stability criterion.<ref>Template:Cite journal</ref>
• 1964 – R. W. Sharp and Charles Misner introduce the Misner–Sharp mass.
• 1964 – Hong-Yee Chiu coins the term "'quasar" for quasi-stellar radio sources.<ref>Template:Cite journal</ref>
• 1964 – Sjur Refsdal suggests that the Hubble constant could be determined using gravitational lensing.<ref>Template:Cite journal</ref>
• 1964 – Irwin Shapiro predicts a gravitational time delay of radiation travel as a test of general relativity.<ref name="Shapiro1964">Template:Cite journal</ref><ref>Template:Cite news</ref>
• 1965 – Roger Penrose proves the first singularity theorem.<ref>Template:Cite journal</ref><ref name=":22" />
• 1965 – Penrose discovers the structure of the light cones in gravitational plane wave spacetimes.
• 1965 – Ezra Newman and others introduce Kerr-Newman metric.<ref>Template:Cite journal</ref><ref>Template:Cite journal</ref>
• 1965 – Arno Penzias and Robert Wilson accidentally discover the cosmic microwave background radiation.<ref>Template:Cite journal</ref> This rules out the steady-state model of Fred Hoyle and Jayant Narlikar.<ref name=":22" />
• 1965 – Joseph Weber puts the first Weber bar gravitational wave detector into operation.
• 1966 – Sachs and Ronald Kantowski discover the Kantowski-Sachs dust solution.
• 1967 – John Archibald Wheeler popularizes "black hole" at a conference.<ref name=":6" /><ref>Template:Cite book</ref>
• 1967 – Jocelyn Bell and Antony Hewish discover pulsars.<ref name=":1">Template:Cite journal</ref>
• 1967 – Robert H. Boyer and R. W. Lindquist introduce Boyer–Lindquist coordinates for the Kerr vacuum.
• 1967 – Bryce DeWitt publishes on canonical quantum gravity.<ref>Template:Cite journal</ref>
• 1967 – Werner Israel proves a special case of the no-hair theorem and the converse of Birkhoff's theorem.<ref>Template:Cite journal</ref>
• 1967 – Kenneth Nordtvedt develops PPN formalism.
• 1967 – Mendel Sachs publishes factorization of Einstein's field equations.
• 1967 – Hans Stephani discovers the Stephani dust solution.
• 1968 – F. J. Ernst discovers the Ernst equation.
• 1968 – B. Kent Harrison discovers the Harrison transformation, a solution-generating method.
• 1968 – Brandon Carter solves the geodesic equations for Kerr–Newmann electrovacuum with Carter's constant.<ref name="carter_1968">Template:Cite journal</ref>
• 1968 – Hugo D. Wahlquist discovers the Wahlquist fluid.
• 1968 – James Hartle and Kip Thorne obtain the Hartle–Thorne metric.<ref>Template:Cite journal</ref>
• 1968 – Irwin Shapiro and his colleagues present the first detection of the Shapiro delay.<ref name="Shapiro1968">Template:Cite journal</ref>
• 1968 – Kenneth Nordtvedt studies a possible violation of the weak equivalence principle for self-gravitating bodies and proposes a new test of the weak equivalence principle based on observing the relative motion of the Earth and Moon in the Sun's gravitational field.<ref>Template:Cite journal</ref>
• 1969 – William B. Bonnor introduces the Bonnor beam.<ref>Template:Cite journal</ref>
• 1969 – Joseph Weber reports observation of gravitational waves<ref>Template:Cite news</ref> a claim now generally discounted.<ref name="Science Magazine">{{#invoke:citation/CS1|citation

|CitationClass=web }}</ref><ref>David Kaiser, "Learning from Gravitational Waves", New York Times, October 3, 2017.</ref>

• 1969 – Penrose proposes the (weak) cosmic censorship hypothesis and the Penrose process,<ref>Template:Cite journal</ref>
• 1969 – Misner introduces the mixmaster universe.
• 1969 – Yvonne Choquet-Bruhat and Robert Geroch discuss global aspects of the Cauchy problem in general relativity.<ref>Template:Cite journal</ref>
• 1965-70 – Subrahmanyan Chandrasekhar and colleagues develops the post-Newtonian expansions.<ref>Template:Cite journal</ref><ref>Template:Cite journal</ref><ref>Template:Cite journal</ref><ref>Template:Cite journal</ref><ref>Template:Cite journal</ref>
• 1968-70 – Roger Penrose, Stephen Hawking, and George Ellis prove that singularities must arise in the Big Bang models.<ref>Template:Cite journal</ref><ref>Template:Cite journal</ref>

1970s

• 1970 – Vladimir Alekseevich Belinski, Isaak Markovich Khalatnikov, and Evgeny Lifshitz introduce the BKL conjecture.
  File:Apollo 15 feather and hammer drop.ogv

  Using a hammer and a feather, Scott validates Galileo's claim that objects in a vacuum will fall at the same rate.
• 1970 – Stephen Hawking and Roger Penrose prove trapped surfaces must arise in black holes.
• 1971 – David Scott demonstrates that a hammer and a feather fall at the same rate on the Moon.<ref name=":11" />
• 1971 – Alfred Goldhaber and Michael Nieto give stringent limits on the photon mass.<ref>Template:Cite journal</ref> The strictest one is <math>m_{\gamma} \leq 4 \times 10^{-51} \text{kg}</math>.<ref>Template:Cite book</ref>
• 1971 – Stephen Hawking proves that the area of a black hole can never decrease.<ref>Template:Cite journal</ref><ref name=":22" />
• 1971 – Peter C. Aichelburg and Roman U. Sexl introduce the Aichelburg–Sexl ultraboost.
• 1971 – Introduction of the Khan–Penrose vacuum, a simple explicit colliding plane wave spacetime.
• 1971 – Robert H. Gowdy introduces the Gowdy vacuum solutions (cosmological models containing circulating gravitational waves).
  File:Chandra image of Cygnus X-1.jpg

  Image of Cygnus X-1 by the Chandra X-ray Observatory (2009)
• 1971 – Cygnus X-1, the first solid black hole candidate, discovered by Uhuru satellite.<ref name=":22" />
• 1971 – William H. Press discovers black hole ringing by numerical simulation.
• 1971 – Harrison and Estabrook algorithm for solving systems of PDEs.
• 1971 – James W. York introduces conformal method generating initial data for ADM initial value formulation.
• 1971 – Robert Geroch introduces Geroch group and a solution generating method.
• 1972 – Jacob Bekenstein proposes that black holes have a non-decreasing entropy which can be identified with the area.<ref>Template:Cite journal</ref><ref name=":22" />
• 1972 – Sachs introduces optical scalars and proves peeling theorem.
• 1972 – Rainer Weiss proposes concept of interferometric gravitational wave detector in an unpublished manuscript.<ref>Cho, Adrian (October 3, 2017). "Ripples in space: U.S. trio wins physics Nobel for discovery of gravitational waves," Science. Retrieved May 20, 2019.</ref>
• 1972 – Joseph Hafele and Richard Keating perform the Hafele–Keating experiment.<ref name="paper1">Template:Cite journal</ref><ref name="paper2">Template:Cite journal</ref><ref name="New Scientist 1972">Template:Cite journal</ref>
• 1972 – Richard H. Price studies gravitational collapse with numerical simulations.
• 1972 – Saul Teukolsky derives the Teukolsky equation.<ref>Template:Cite journal</ref>
• 1972 – Yakov B. Zel'dovich predicts the transmutation of electromagnetic and gravitational radiation.
• 1972 – Brandon Carter, Stephen Hawking, and James M. Bardeen propose the four laws of black hole mechanics.<ref>Template:Cite journal</ref><ref name=":22" />
• 1972 – James Bardeen calculates the shadow of a black hole.<ref>Template:Cite journal</ref> This was later verified by the Event Horizon Telescope.<ref>Template:Cite news</ref>
• 1973 – Charles W. Misner, Kip S. Thorne and John A. Wheeler publish the treatise Gravitation, a textbook that remains in use in the twenty-first century.<ref>Template:Cite journal</ref><ref>Template:Cite news</ref>
• 1973 – Stephen W. Hawking and George Ellis publish the monograph The Large Scale Structure of Space-Time.<ref name=":22" />
• 1973 – Robert Geroch introduces the GHP formalism.
• 1973 – Homer Ellis obtains the Ellis drainhole,<ref name="ellis12">Template:Cite journal</ref> the first traversable wormhole.
• 1974 – Russell Hulse and Joseph Hooton Taylor, Jr. discover the Hulse–Taylor binary pulsar,
• File:BH-JPL-A&A1979.jpg

  Computer simulation of a black hole accretion disk published in 1979 by Jean-Pierre Luminet
  1974 – James W. York and Niall Ó Murchadha present the analysis of the initial value formulation and examine the stability of its solutions.
• 1974 – R. O. Hansen introduces Hansen–Geroch multipole moments.
• 1974 – Stephen Hawking discovers Hawking radiation.<ref>Template:Cite journal</ref><ref>Template:Cite journal</ref>
• 1975 – Stephen Hawking shows that the area of a black hole is proportional to its entropy, as previously conjectured by Jacob Bekenstein.<ref>Template:Cite journal</ref>
• 1975 – Roberto Colella, Albert Overhauser, and Samuel Werner observe the quantum-mechanical phase shift of neutrons due to gravity.<ref>Template:Cite journal</ref> Neutron interferometry was later used to test the principle of equivalence.<ref>Template:Cite journal</ref><ref>Template:Cite journal</ref><ref>Template:Cite book</ref>
• 1975 – Chandrasekhar and Steven Detweiler compute the effects of perturbations on a Schwarzschild black hole.<ref>Template:Cite journal</ref>
• 1975 – Szekeres and D. A. Szafron discover the Szekeres–Szafron dust solutions.
• 1976 – Penrose introduces Penrose limits (every null geodesic in a Lorentzian spacetime behaves like a plane wave),
• 1978 – Penrose introduces the notion of a thunderbolt,
• 1978 – Belinskiǐ and Zakharov show how to solve Einstein's field equations using the inverse scattering transform; the first gravitational solitons,
• 1979 – Dennis Walsh, Robert Carswell, and Ray Weymann discover the gravitationally lensed quasar Q0957+561.<ref>Template:Cite journal</ref>
• 1979 – Jean-Pierre Luminet creates an image of a black hole with an accretion disk using computer simulation.<ref>Template:Cite journal</ref><ref>Template:Cite news</ref>
• 1979 – Steven Detweiler proposes using pulsar timing arrays to detect gravitational waves.<ref name="DetweilerPulsarTiming">Template:Cite journal</ref>
• 1979-81 – Richard Schoen and Shing-Tung Yau prove the positive mass theorem.<ref>Template:Cite journal</ref><ref>Template:Cite journal</ref> Edward Witten independently proves the same thing.<ref>Template:Cite journal</ref>

1980s

File:COBE cmb fluctuations.png

Variations in the temperature of the cosmic microwave background measured by the COBE satellite. The plane of the Milky Way Galaxy is horizontal across the middle of each picture.

• 1980 – Vera Rubin and colleagues study the rotational properties of UGC 2885, demonstrating the prevalence of dark matter.<ref>Template:Cite journal</ref><ref>{{#invoke:citation/CS1|citation

|CitationClass=web }}</ref>

• 1980 – Gravity Probe A verifies gravitational redshift to approximately 0.007% using a space-born hydrogen maser.<ref>Template:Cite journal</ref>
• 1980 – James Bardeen explains structure in the Universe using cosmological perturbation theory.<ref>Template:Cite journal</ref>
• 1981 – Alan Guth proposes cosmic inflation in order to solve the flatness and horizon problems.<ref>Template:Cite journal</ref>
• 1982 – Joseph Taylor and Joel Weisberg show that the rate of energy loss from the binary pulsar PSR B1913+16 agrees with that predicted by the general relativistic quadrupole formula to within 5%.<ref name="tw82">Template:Cite journal</ref>
• 1983 – James Hartle and Stephen Hawking propose the no-boundary wave function for the Universe.<ref>Template:Cite journal</ref><ref name=":22" />
• 1983-84 – RELIKT-1 observes the cosmic microwave background.
• 1986 – Helmut Friedrich proves that the de Sitter spacetime is stable.<ref>Template:Cite journal</ref><ref name=":0">Template:Cite news</ref>
• 1986 – Bernard Schutz shows that cosmic distances can be determined using sources of gravitational waves without references to the cosmic distance ladder.<ref>Template:Cite journal</ref> Standard-siren astronomy is born.
• 1988 – Mike Morris, Kip Thorne, and Yurtsever Ulvi obtain the Morris-Thorne wormhole.<ref>Template:Cite journal</ref> Morris and Thorne argue for its pedagogical value.<ref>Template:Cite journal</ref>
• 1989 – Steven Weinberg discusses the cosmological constant problem, the discrepancy between the measured value and those predicted by modern theories of elementary particles.<ref>Template:Cite journal</ref>
• 1989-93 – The Cosmic Background Explorer (COBE) identifies anisotropy in the cosmic microwave background.<ref>Template:Cite journal</ref><ref>Template:Cite journal</ref>

1990s

File:GR2bodyparameterspace.png

Parameter space of various approximation techniques in general relativity

• 1992 – Stephen Hawking states his chronology protection conjecture.<ref>Template:Cite journal</ref>
• 1993 – Demetrios Christodoulou and Sergiu Klainerman prove the non-linear stability of the Minkowski spacetime.<ref>Template:Cite book</ref><ref name=":0" />
• 1995 – John F. Donoghue show that general relativity is a quantum effective field theory.<ref>Template:Cite journal</ref> This framework could be used to analyze binary systems observed by gravitational-wave observatories.<ref>Template:Cite journal</ref>
• 1995 – Hubble Deep Field image taken.<ref name="Hubble_image">{{#invoke:citation/CS1|citation

|CitationClass=web }}</ref> It is a landmark in the study of cosmology.

• 1998 – The first complete Einstein ring, B1938+666, discovered using the Hubble Space Telescope and MERLIN.<ref name="Bullseye">{{#invoke:citation/CS1|citation

|CitationClass=web }}</ref><ref>Template:Cite news</ref>

• 1998-99 – Scientists discover that the expansion of the Universe is accelerating.<ref>Template:Cite journal</ref><ref>Template:Cite journal</ref>
• 1999 – Alessandra Buonanno and Thibault Damour introduce the effective one-body formalism.<ref>Template:Cite journal</ref> This was later used to analyze data collected by gravitational-wave observatories.<ref>Template:Cite journal</ref>

2000s

• 2003 – Arvind Borde, Alan Guth, and Alexander Vilenkin prove the Borde–Guth–Vilenkin theorem.<ref>Template:Cite journal</ref><ref name="Cosmocurious">Template:Cite book</ref>
• 2002 – First data collection of the Laser Interferometer Gravitational-Wave Observatory (LIGO).
• 2002 – James Williams, Slava Turyshev, and Dale Boggs conduct stringent lunar test of violations of the principle of equivalence.<ref>Template:Cite journal</ref>
• 2005 – Daniel Holz and Scott Hughes coin the term "standard sirens".<ref>Template:Cite journal</ref>
• 2009 – Gravity Probe B experiment verifies the geodetic effect to 0.5%.<ref>{{#invoke:citation/CS1|citation

|CitationClass=web }}</ref><ref name="PRL">Template:Cite journal</ref>

2010s

File:PIA16874-CobeWmapPlanckComparison-20130321.jpg

Improving cosmological measurements by three different satellites

• 2010 – A team at the U.S. National Institute for Standards and Technology (NIST) verifies relativistic time dilation using optical atomic clocks.<ref>Template:Cite journal</ref><ref>Template:Cite journal</ref>
• 2011 – Wilkinson Microwave Anisotropy Probe (WMAP) finds no statistically significant deviations from the ΛCDM model of cosmology.<ref name="WMAP CMB">Template:Cite journal</ref>
• 2012 – Hubble Ultra-Deep Field image released. It was created using data collected by the Hubble Space Telescope between 2003 and 2004.<ref name="xdf">{{#invoke:citation/CS1|citation

|CitationClass=web }}</ref>

• 2013 – NuSTAR and XMM-Newton measure the spin of the supermassive black hole at the center of the galaxy NGC 1365.<ref>Template:Cite news Template:PD-notice</ref>
• 2015 – Advanced LIGO reports the first direct detections of gravitational waves, GW150914<ref>Template:Cite journal</ref> and GW151226,<ref name="PRL-20160615">Template:Cite journal</ref> mergers of stellar-mass black holes. Gravitational-wave astronomy is born.<ref name="Naeye">Template:Cite news</ref> No deviations from general relativity were found.<ref>Template:Cite news</ref><ref name="MIT">Template:Cite news</ref>
• 2017 – LIGO-VIRGO collaboration detects gravitational waves emitted by a neutron-star binary, GW170817.<ref name=":3">Template:Cite journal</ref> The Fermi Gamma-ray Space Telescope and the International Gamma-ray Astrophysics Laboratory (INTEGRAL) unambiguously detect the corresponding gamma-ray burst.<ref name=":5">Template:Cite journal</ref><ref>Template:Cite journal</ref> LIGO-VIRGO and Fermi constrain the difference between the speed of gravity and the speed of light in vacuum to Template:10^.<ref name="Abbott^3_AJT">Template:Cite journal</ref> This marks the first time electromagnetic and gravitational waves are detected from a single source,<ref>Template:Cite journal</ref><ref>Template:Cite news</ref> and give direct evidence that some (short) gamma-ray bursts are due to colliding neutron stars.<ref name=":3" /><ref name=":5" />
• 2017 – Multi-messenger astronomy reveals neutron-star mergers to be responsible for the nucleosynthesis of some heavy elements,<ref name="SM-20171016">Template:Cite journal</ref><ref name="NASA-20171016">Template:Cite news</ref><ref>Template:Cite journal</ref><ref>Template:Cite journal</ref> such as strontium,<ref>Template:Cite journal</ref> via the rapid-neutron capture or r-process.<ref>Template:Cite journal</ref>
• 2017 – MICROSCOPE satellite experiment verifies the principle of equivalence to Template:10^ in terms of the Eötvös ratio <math>\eta</math>.<ref name="Touboul2017">Template:Cite journal</ref> The final report is published in 2022.<ref>Template:Cite journal</ref><ref>Template:Cite journal</ref>
• 2017 – Principle of equivalence tested to 10⁻⁹ for atoms in a coherent state of superposition.<ref>Template:Cite journal</ref>
• 2017 – Scientists begin using gravitational-wave sources as "standard sirens" to measure the Hubble constant, finding its value to be broadly in line with the best estimates of the time.<ref>Template:Cite journal</ref><ref name="Nat24471">Template:Cite journal</ref> Refinements of this technique will help resolve discrepancies between the different methods of measurements.<ref name="NAT-20181017">Template:Cite journal</ref>
• 2017 – Neutron Star Interior Composition Explorer (NICER) arrives on the International Space Station.<ref name=":1" />
• 2017-18 – Georgios Moschidis proves the instability of the anti-de Sitter spacetime.<ref name=":0" />
• 2018 – Final paper by the Planck satellite collaboration.<ref name="planck2018">Template:Cite journal</ref> Planck operated between 2009 and 2013.
• 2018 – Mihalis Dafermos and Jonathan Luk disprove the strong cosmic censorship hypothesis for the Cauchy horizon of an uncharged, rotating black hole.<ref>Template:Cite magazine</ref>
• 2018 – European Southern Observatory (ESO) observes gravitational redshift of radiation emitted by matter orbiting Sagittarius A*, the central supermassive black hole of the Milky Way,<ref>Template:Cite journal</ref> and verifies the innermost stable circular orbit for that object.<ref>Template:Cite journal</ref>
• 2018 – Advanced LIGO-VIRGO collaboration constrains equations of state for a neutron star using GW170817.<ref>Template:Cite journal</ref><ref>Template:Cite journal</ref>
• 2018 – Luciano Rezzolla, Elias R. Most, and Lukas R. Weih used gravitational-wave data from GW170817 constrain the possible maximum mass for a neutron star to around 2.17 solar masses.<ref name="Rezzolla2018">Template:Cite journal</ref>
• 2018 – Kris Pardo, Maya Fishbach, Daniel Holz, and David Spergel limit the number of spacetime dimensions through which gravitational waves can propagate to 3 + 1, in line with general relativity and ruling out models that allow for "leakage" to higher dimensions of space.<ref name="arxiv.org 2">Template:Cite journal</ref><ref>Template:Cite news</ref> Analyses of GW170817 have also ruled out many other alternatives to general relativity,<ref>Template:Cite journal</ref><ref>Template:Cite journal</ref><ref>Template:Cite journal</ref><ref>Template:Cite journal</ref> and proposals for dark energy.<ref name="Dark Energy after GW 170817">Template:Cite journal</ref><ref>Template:Cite journal</ref><ref name="Dark Energy After GW170817: Dead En">Template:Cite journal</ref><ref>Template:Cite journal</ref><ref>Template:Cite news</ref>
• 2018 – Two different experimental teams report highly precise values of Newton's gravitational constant <math>G</math> that slightly disagree.<ref>Template:Cite journal</ref><ref>Template:Cite journal</ref><ref>Template:Cite news</ref>
• 2019 – Event Horizon Telescope (EHT) releases an image of supermassive black hole M87*, and measures its mass and shadow.<ref>Template:Cite journal</ref><ref>Template:Cite news</ref> Results are confirmed in 2024.<ref>Template:Cite journal</ref>
• 2019 – Advanced LIGO and VIRGO detect GW190814, the collision of a 26-solar-mass black hole and a 2.6-solar-mass object, either an extremely heavy neutron star or a very light black hole.<ref name="LIGO-2020">Template:Cite news</ref><ref name="AJL-20200623">Template:Cite journal</ref> This is the largest mass gap seen in a gravitational-wave source to-date.

2020s

File:Eso2208-eht-mwe.tif

The size of Sagittarius A* is smaller than the orbit of Mercury.

• 2020 – Principle of equivalence tested for individual atoms using atomic interferometry to ~10⁻¹².<ref>Template:Cite journal</ref><ref>Template:Cite news</ref>
• 2020 – ESO observes Schwarzschild precession of the star S2 about Sagittarius A*.<ref>Template:Cite journal</ref>
• 2021 – Jun Ye and his team measure gravitational redshift with an accuracy of 7.6 × 10⁻²¹ using an ultracold cloud of 100,000 strontium atoms in an optical lattice.<ref>Template:Cite journal</ref><ref>{{#invoke:citation/CS1|citation

|CitationClass=web }}</ref>

• 2021 – EHT measures the polarization of the ring of M87*,<ref>Template:Cite journal</ref> and other properties of the magnetic field in its vicinity.<ref>Template:Cite journal</ref>
• 2021 – EHT releases an image of Sagittarius A*,<ref name="AJ-202205">Template:Cite journal</ref><ref name="NYT-20220512">Template:Cite news</ref> measures its shadow,<ref>Template:Cite journal</ref> and shows that it is accurately described by the Kerr metric.<ref>Template:Cite journal</ref><ref>Template:Cite journal</ref>
• 2022 – Chris Overstreet and his team observe the gravitational Aharonov-Bohm effect<ref>Template:Cite journal</ref><ref>{{#invoke:citation/CS1|citation

|CitationClass=web }}</ref><ref>Template:Cite news</ref> using an experimental design from 2012.<ref>Template:Cite journal</ref><ref>Template:Cite journal</ref>

• 2022 – James Webb Space Telescope (JWST) publishes its first image, a deep-field photograph of the SMACS 0723 galaxy cluster.<ref>{{#invoke:citation/CS1|citation

|CitationClass=web }}</ref>

• 2022 – Neil Gehrels Swift Observatory detects GRB 221009A, the brightest gamma-ray burst recorded.<ref>Template:Cite journal</ref><ref name=":2">Template:Cite journal</ref><ref name="NASA20221013">{{#invoke:citation/CS1|citation

|CitationClass=web }}</ref>

• 2022 – JWST identifies several candidate high-redshift objects, corresponding to just a few hundred million years after the Big Bang.<ref name="MNRAS-20230101">Template:Cite journal</ref><ref name="Yan2023">Template:Cite journal</ref>
• 2023 – James Nightingale and colleagues detect Abell 1201, an ultramassive black hole (33 billion solar masses), using strong gravitational lensing.<ref>Template:Cite journal</ref>
• 2023 – Matteo Bachetti and colleagues confirm that neutron star M82 X-2 is violating the Eddington limit, making it an ultraluminous X-ray source (ULX).<ref>{{#invoke:citation/CS1|citation

|CitationClass=web }}</ref><ref>Template:Cite journal</ref>

• 2023 – Team led by Dong Sheng and Zheng-Tian Lu found a null result for the coupling between quantum spin and gravity to 10⁻⁹.<ref>Template:Cite journal</ref><ref>Template:Cite news</ref>
• 2023 – The North American Nanohertz Observatory for Gravitational Waves (NANOGrav), the European Pulsar Timing Array (EPTA), the Parkes Pulsar Timing Array (Australia), and the Chinese Pulsar Timing Array report detection of a gravitational-wave background.<ref>Template:Cite journal</ref><ref>Template:Cite journal</ref><ref>Template:Cite journal</ref><ref>Template:Cite journal</ref><ref>Template:Cite news</ref>
• 2023 – Geraint F. Lewis and Brendon Brewer present evidence of cosmological time dilation in quasars.<ref>Template:Cite journal</ref><ref>Template:Cite news</ref>
• 2024 – The Large High Altitude Air Shower Observatory (LHAASO) collaboration imposes stringent limits on violations of Lorentz invariance proposed in certain theories of quantum gravity using GRB 221009A.<ref>Template:Cite journal</ref><ref>Template:Cite news</ref>

See also

• Timeline of black hole physics
• Timeline of special relativity and the speed of light
• List of contributors to general relativity
• List of scientific publications by Albert Einstein

External links

• Timeline of relativity and gravitation (Tomohiro Harada, Department of Physics, Rikkyo University)
• Timeline of General Relativity and Cosmology from 1905
• 2015–General Relativity's Centennial. Physical Review Journals. American Physical Society (APS).