Andreas Vesalius1543 · Anatomist, physician and author (1514–1564) (placed at Mont aux Potences - Galgenberg)Known works: De humani corporis fabrica. 1543: Vesalius : pioneering research into human anatomy.https://en.wikipedia.org/wiki/Andreas_Vesalius
Nicolaus Copernicus1543 · Mathematician and astronomer (1473–1543) (placed at Toruń)Known works: Commentariolus, De revolutionibus orbium coelestium. 1543: Nicolaus Copernicus develops a heliocentric model , rejecting Aristotle's Earth-centric view, would be the first quantitative heliocentric model in history.https://en.wikipedia.org/wiki/Nicolaus_Copernicus
Robert Recorde1557 · Welsh mathematician and inventor of the equals sign (placed at Tenby)Known works: The Whetstone of Witte, The Ground of Arts, The Castle of Knowledge. 1557: Robert Recorde introduces the equal sign.https://en.wikipedia.org/wiki/Robert_Recorde
Gerolamo Cardano1564 · Italian Renaissance polymath (1501–1576) (placed at Province of Pavia)Known works: Ars Magna, De subtilitate rerum, Hieronymi Cardani medici Mediolanensis Contradicentium medicorum liber primus [-secundus], gimbal. 1564: Gerolamo Cardano is the first to produce a systematic treatment of probability.https://en.wikipedia.org/wiki/Gerolamo_Cardano
Johannes Kepler1609 · German astronomer and mathematician (1571–1630) (placed at Weil der Stadt)Known works: Astronomia nova, Harmonices Mundi, Epitome Astronomiae Copernicanae, De Cometis Libelli Tres, Rudolphine Tables, Astronomiae Pars Optica. 1609: Johannes Kepler : first two laws of planetary motion.https://en.wikipedia.org/wiki/Johannes_Kepler
Galileo Galilei1610 · Italian physicist and astronomer (1564–1642) (placed at Pisa)Known works: Galilean transformation, equations for a falling body. 1610: Galileo Galilei : Sidereus Nuncius : telescopic observations.https://en.wikipedia.org/wiki/Galileo_Galilei
John Napier1614 · Scottish mathematician (1550–1617) (placed at Merchiston Tower)Known works: Mirifici logarithmorum canonis descriptio, Napier's bones, Location arithmetic, Rabdology, Promptuary, Plaine Discovery of the Whole Revelation of Saint John. 1614: John Napier : use of logarithms for calculation.https://en.wikipedia.org/wiki/John_Napier
Evangelista Torricelli1643 · Italian physicist and mathematician (1608–1647) (placed at Rome)Known works: Opera Geometrica, Torricelli's law, Gabriel's Horn, Torricelli's experiment, Torricelli's equation, torricellian chamber, barometer. 1643: Evangelista Torricelli invents the mercury barometer .https://en.wikipedia.org/wiki/Evangelista_Torricelli
Robert Boyle1662 · Anglo-Irish scientist (1627–1691) (placed at Lismore)Known works: Boyle's law, New Experiments Physico-Mechanicall, Touching the Spring of the Air and its Effects, The Sceptical Chymist. 1662: Robert Boyle : Boyle's law of ideal gases.https://en.wikipedia.org/wiki/Robert_Boyle
Robert Hooke1665 · English polymath (1635–1703) (placed at Freshwater)Known works: Micrographia, Hooke's law, Church of St Mary Magdalene, Montagu House, Bethlem Royal Hospital at Moorfields. 1665: Robert Hooke : discovers the cell.https://en.wikipedia.org/wiki/Robert_Hooke
Nicolas Steno1669 · Danish scientist and Catholic bishop (1638 – 1686) (placed at Copenhagen)1669: Nicholas Steno : proposes that fossils are organic remains embedded in layers of sediment, basis of stratigraphy .https://en.wikipedia.org/wiki/Nicolas_Steno
Isaac Newton1672 · English polymath (1642–1727) (placed at Woolsthorpe Manor)Known works: Philosophiæ Naturalis Principia Mathematica, Method of Fluxions, Opticks, or a Treatise of the Reflections, Refractions, Inflections and Colours of Light. 1672: Sir Isaac Newton : discovers that white light is a mixture of distinct coloured rays (the spectrum ).https://en.wikipedia.org/wiki/Isaac_Newton
Christiaan Huygens1673 · Dutch mathematician and physicist (1629–1695) (placed at The Hague)Known works: Horologium Oscillatorium, De Saturni Luna Observatio Nova, Systema Saturnium, Treatise on Light, De Circuli Magnitudine Inventa, Cosmotheoros. 1673: Christiaan Huygens : first study of oscillating system and design of pendulum clockshttps://en.wikipedia.org/wiki/Christiaan_Huygens
Gottfried Wilhelm Leibniz1675 · German polymath (1646–1716) (placed at Leipzig)Known works: Discourse on Metaphysics, Théodicée, integral calculus, Stepped Reckoner, Q19234609, Monadology, Leibniz's notation, calculus ratiocinator. 1675: Leibniz , Newton : infinitesimal calculus .https://en.wikipedia.org/wiki/Gottfried_Wilhelm_Leibniz
Carl Linnaeus1735 · Swedish biologist and physician (1707–1778) (placed at Råshult)Known works: Systema Naturae, Species Plantarum, Genera Plantarum, Fundamenta Botanica, Critica Botanica, Bibliotheca Botanica, Amoenitates Academicae, Hortus Cliffortianus. 1735: Carl Linnaeus described a new system for classifying plants in Systema Naturae .https://en.wikipedia.org/wiki/Carl_Linnaeus
Immanuel Kant1755 · German philosopher (1724–1804) (placed at Königsberg)Known works: Critique of Pure Reason, Critique of Practical Reason, Critique of Judgment, Prolegomena to Any Future Metaphysics, Answering the Question: What Is Enlightenment?, The Metaphysics of Morals, Religion within the Bounds of Bare Reason, Groundwork of the Metaphysic of Morals. 1755: Immanuehttps://en.wikipedia.org/wiki/Immanuel_Kant
Thomas Bayes1763 · British statistician (c. 1701 – 1761) (placed at London)Known works: An Essay towards solving a Problem in the Doctrine of Chances, Bayes' theorem. 1763: Thomas Bayes : publishes the first version of Bayes' theorem , paving the way for Bayesian probability .https://en.wikipedia.org/wiki/Thomas_Bayes
Aryabhata1765 · Indian mathematician-astronomer (476–550) (placed at Pataliputra)Known works: Āryabhaṭīya, Arya Siddhanta, Āryabhaṭa numeration, Āryabhaṭa's sine table. 499: Aryabhata creates a particularly accurate eclipse chart. As an example of its accuracy, 18th century scientist Guillaume Le Gentil , during a visit to Pondicherry, India, found the Indian computations (basedhttps://en.wikipedia.org/wiki/Aryabhata
Charles Messier1771 · 18th- and 19th-century French astronomer (placed at Badonviller)Known works: Messier object, Lexell's Comet. 1771: Charles Messier : publishes catalogue of astronomical objects ( Messier Objects ) now known to include galaxies, star clusters, and nebulae.https://en.wikipedia.org/wiki/Charles_Messier
Antoine Lavoisier1778 · French nobleman and chemist (1743–1794) (placed at Paris)Known works: Traité Élémentaire de Chimie, Méthode de nomenclature chimique, conservation of mass. 1778: Antoine Lavoisier (and Joseph Priestley ): discovery of oxygen leading to end of Phlogiston theory .https://en.wikipedia.org/wiki/Antoine_Lavoisier
William Herschel1781 · German-British astronomer and composer (1738–1822) (placed at Hanover)Known works: Account of a Comet. By Mr. Herschel, F. R. S.; Communicated by Dr. Watson, Jun. of Bath, F. R. S, discovery of Uranus, Herschel wedge, infrared radiation. 1781: William Herschel announces discovery of Uranus , expanding the known boundaries of the Solar System for the first time in modehttps://en.wikipedia.org/wiki/William_Herschel
John Dalton1805 · British chemist and physicist (1766–1844) (placed at Cumberland)Known works: History of atomic theory, dalton, color blindness, law of multiple proportions, Dalton's law, A New System of Chemical Philosophy. 1805: John Dalton : Atomic Theory in ( chemistry ).https://en.wikipedia.org/wiki/John_Dalton
Michael Faraday1820 · English chemist and physicist (1791–1867) (placed at Newington Butts)1820: Michael Faraday and James Stoddart discover alloying iron with chromium produces a stainless steel resistant to oxidising elements ( rust ).https://en.wikipedia.org/wiki/Michael_Faraday
Joseph Aspdin1824 · English inventor of Portland cement (1778–1855) (placed at Leeds)Known works: portland cement. 1824: Joseph Aspdin develops Portland cement ( concrete ), by heating ground limestone, clay and gypsum, in a kiln.https://en.wikipedia.org/wiki/Joseph_Aspdin
Nikolai Lobachevsky1830 · Russian mathematician (1792–1856) (placed at Nizhny Novgorod)Known works: hyperbolic geometry, Test of Lobachevsky, Graeffe's method, Lobachevsky integral formula. 1830: Nikolai Lobachevsky created Non-Euclidean geometry .https://en.wikipedia.org/wiki/Nikolai_Lobachevsky
Charles Babbage1837 · English mathematician, philosopher, and engineer (1791–1871) (placed at Walworth)Known works: analytical engine, On the Economy of Machinery and Manufactures, Reflections on the Decline of Science in England, and on Some of Its Causes, difference engine, Passages from the Life of a Philosopher., Laws of mechanical notation (for consideration) / [C. Babbage], Ninth Bridgewater Trhttps://en.wikipedia.org/wiki/Charles_Babbage
Friedrich Wilhelm Bessel1838 · German astronomer and mathematician (1784–1846) (placed at Minden)Known works: Fundamenta Astronomiae, Bessel function, Bessel ellipsoid, Bessel polynomials, Besselian elements, Bessel's correction, Bessel's inequality, Q6174265. 1838: Friedrich Bessel : first successful measure of stellar parallax (to star 61 Cygni ).https://en.wikipedia.org/wiki/Friedrich_Wilhelm_Bessel
Christian Doppler1842 · Austrian mathematician and physicist (1803–1853) (placed at Salzburg)Known works: Doppler effect, Über das farbige Licht der Doppelsterne und einiger anderer Gestirne des Himmels. 1842: Christian Doppler : Doppler effect .https://en.wikipedia.org/wiki/Christian_Doppler
James Prescott Joule1843 · English physicist (1818–1889) (placed at Salford)Known works: thermodynamics. 1843: James Prescott Joule : Law of Conservation of energy ( first law of thermodynamics ), also 1847 – Helmholtz , Conservation of energy.https://en.wikipedia.org/wiki/James_Prescott_Joule
George Boole1847 · English mathematician and philosopher (1815–1864) (placed at Lincoln)Known works: Boolean algebra, Boole's inequality, Boolean function, The Laws of Thought, Boole's rule, The Mathematical Analysis of Logic. 1847: George Boole : publishes The Mathematical Analysis of Logic , defining Boolean algebra ; refined in his 1854 The Laws of Thought .https://en.wikipedia.org/wiki/George_Boole
Lord Kelvin1848 · British physicist, engineer and mathematician (1824–1907) (placed at Belfast)Known works: ampere balance, Kelvin–Voigt material, Lunar, Automatic curb sender, Kelvin probe force microscope, Kelvin–Varley divider. 1848: Lord Kelvin : absolute zero .https://en.wikipedia.org/wiki/Lord_Kelvin
Robert Forester Mushet1856 · British metallurgist and businessman (placed at Coleford)1856: Robert Forester Mushet develops a process for the decarbonisation, and re-carbonisation of iron, through the addition of a calculated quantity of spiegeleisen , to produce cheap, consistently high quality steel .https://en.wikipedia.org/wiki/Robert_Forester_Mushet
Charles Darwin1859 · English naturalist and biologist (1809–1882) (placed at The Mount)Known works: On the Tendency of Species to form Varieties; and on the Perpetuation of Varieties and Species by Natural Means of Selection, On the Origin of Species, The Voyage of the Beagle, The Descent of Man, and Selection in Relation to Sex, The Expression of the Emotions in Man and Animals, Insehttps://en.wikipedia.org/wiki/Charles_Darwin
James Clerk Maxwell1864 · Scottish physicist and mathematician (1831–1879) (placed at Edinburgh)Known works: A Dynamical Theory of the Electromagnetic Field, Maxwell's equations, Maxwell–Boltzmann statistics, Maxwell's demon. 1864: James Clerk Maxwell : Theory of electromagnetism .https://en.wikipedia.org/wiki/James_Clerk_Maxwell
William Crookes1875 · English chemist and physicist (1832–1919) (placed at London)Known works: Crookes tube, Crookes radiometer, discovery. 1875: William Crookes invented the Crookes tube and studied cathode rays .https://en.wikipedia.org/wiki/William_Crookes
Josiah Willard Gibbs1876 · American scientist (1839–1903) (placed at New Haven)Known works: Gibbs free energy, Gibbs–Donnan effect, Gibbs paradox, Gibbs algorithm, Gibbs distribution, Gibbs' inequality, Gibbs isotherm, Gibbs phenomenon. 1876: Josiah Willard Gibbs founded chemical thermodynamics , the phase rule .https://en.wikipedia.org/wiki/Josiah_Willard_Gibbs
Ludwig Boltzmann1877 · Austrian mathematician and theoretical physicist (1844–1906) (placed at Vienna)Known works: Boltzmann constant, Stefan-Boltzmann law, Stefan-Boltzmann constant, Boltzmann equation, Boltzmann distribution, Boltzmann's entropy formula, list of things named after Ludwig Boltzmann. 1877: Ludwig Boltzmann : Statistical definition of entropy .https://en.wikipedia.org/wiki/Ludwig_Boltzmann
Pierre Curie1880 · French physicist and chemist (1859–1906) (placed at Paris)Known works: radioactivity, piezoelectricity. 1880: Pierre Curie and Jacques Curie : Piezoelectricity .https://en.wikipedia.org/wiki/Pierre_Curie
Cosmic microwave background1896 · Trace radiation from the early universe (placed at Munich (where Arno Allan Penzias was born))Invented or discovered by: Arno Allan Penzias, Robert Wilson. Discovered or invented: 1964. Timeline of cosmic microwave background astronomy (1896 CE – 2009)https://en.wikipedia.org/wiki/Cosmic_microwave_background
Marie Curie1898 · Polish-French physicist and chemist (1867–1934) (placed at Warsaw)Known works: Treatise on Radioactivity. 1898: Marie Curie discovered radium and poloniumhttps://en.wikipedia.org/wiki/Marie_Curie
Martinus Beijerinck1898 · Dutch microbiologist (1851–1931) (placed at Amsterdam)1898: Martinus Beijerinck : concluded that a virus is infectious—replicating in the host—and thus not a mere toxin, and gave it the name "virus"https://en.wikipedia.org/wiki/Martinus_Beijerinck
Max Planck1900 · German physicist (1858–1947) (placed at Kiel)Known works: Planck's law, Planck constant. 1900: Max Planck : explains the emission spectrum of a black bodyhttps://en.wikipedia.org/wiki/Max_Planck
Albert Einstein1905 · German-born theoretical physicist (1879–1955) (placed at Ulm)Known works: special relativity, general relativity, photoelectric effect, theory of relativity, theory of Brownian Motion, mass–energy equivalence, Planck constant, Einstein field equations. 1905: Albert Einstein : theory of special relativity , explanation of Brownian motion , and photoelectric efhttps://en.wikipedia.org/wiki/Albert_Einstein
Fritz Haber1909 · German chemist (1868–1934) (placed at Wrocław)Known works: Haber-Bosch process, chemical weapon. 1909: Fritz Haber : Haber Process for industrial production of ammoniahttps://en.wikipedia.org/wiki/Fritz_Haber
Karl Schwarzschild1915 · German physicist (1873–1916) (placed at Frankfurt)Known works: Schwarzschild metric, Schwarzschild black hole, Schwarzschild radius, Schwarzschild effect, Schwarzschild coordinates, de Sitter–Schwarzschild metric, Interior Schwarzschild metric, Schwarzschild telescope. 1915: Karl Schwarzschild : discovery of the Schwarzschild radius leading to the https://en.wikipedia.org/wiki/Karl_Schwarzschild
Emmy Noether1918 · German mathematician (1882–1935) (placed at Erlangen)Known works: Noether's theorem. 1918: Emmy Noether : Noether's theorem – conditions under which the conservation laws are validhttps://en.wikipedia.org/wiki/Emmy_Noether
Arthur Eddington1920 · British astrophysicist (1882–1944) (placed at Kendal)Known works: general relativity, Eddington luminosity, Eddington number, arrow of time, Eddington experiment, Κ mechanism, Eddington–Finkelstein coordinates, radiation zone. 1920: Arthur Eddington : Stellar nucleosynthesishttps://en.wikipedia.org/wiki/Arthur_Eddington
Frederick Banting1922 · Canadian medical scientist and doctor (1891–1941) (placed at Alliston)1922: Frederick Banting , Charles Best , James Collip , John Macleod : isolation and production of insulin to control diabeteshttps://en.wikipedia.org/wiki/Frederick_Banting
Edwin Hubble1924 · American astronomer (1889–1953) (placed at Marshfield)Known works: Hubble–Lemaître law, Hubble sequence. 1924: Edwin Hubble : the discovery that the Milky Way is just one of many galaxieshttps://en.wikipedia.org/wiki/Edwin_Hubble
Wolfgang Pauli1924 · Austrian physicist (1900–1958) (placed at Vienna)Known works: Pauli exclusion principle, Pauli matrices, Pauli equation, Pauli effect, Pauli–Villars regularization, Pauli group, Pauli–Lubanski pseudovector. 1924: Wolfgang Pauli : quantum Pauli exclusion principlehttps://en.wikipedia.org/wiki/Wolfgang_Pauli
Lars Onsager1929 · Norwegian-American physical chemist and theoretical physicist (1903-1976) (placed at Norway (Christiania))1929: Lars Onsager 's reciprocal relations, a potential fourth law of thermodynamicshttps://en.wikipedia.org/wiki/Lars_Onsager
Clive McCay1934 · American biochemist, nutritionist and gerontologist (placed at Indiana)1934: Clive McCay : Calorie restriction extends the maximum lifespan of another specieshttps://en.wikipedia.org/wiki/Clive_McCay
Otto Hahn1938 · German nuclear chemist and Nobel laureate (1879–1968) (placed at Frankfurt)1938: Otto Hahn , Lise Meitner and Fritz Strassmann : Nuclear fission of heavy nucleihttps://en.wikipedia.org/wiki/Otto_Hahn
Claude Shannon1948 · American mathematician (1916–2001) (placed at Petoskey)Known works: A Mathematical Theory of Communication, A Symbolic Analysis of Relay and Switching Circuits, Nyquist–Shannon sampling theorem, Shannon's source coding theorem, Noisy-channel coding theorem, Shannon–Hartley theorem, Shannon's expansion, Shannon's generalized De Morgan law. 1948: Claude Ehttps://en.wikipedia.org/wiki/Claude_Shannon
Richard Feynman1948 · American theoretical physicist (1918–1988) (placed at Queens)Known works: “Surely You're Joking, Mr. Feynman!”, The Feynman Lectures on Physics, Feynman diagram, Feynman–Kac formula, Hellmann–Feynman theorem, Cargo Cult Science, The Character of Physical Law, Bethe–Feynman formula. 1948: Richard Feynman , Julian Schwinger , Sin-Itiro Tomonaga and Freeman Dysohttps://en.wikipedia.org/wiki/Richard_Feynman
Stanley Miller1952 · American scientist (1930–2007) (placed at Oakland)1952: Stanley Miller : demonstrated that the building blocks of life could arise from primeval soup in the conditions present during early Earth ( Miller-Urey experiment )https://en.wikipedia.org/wiki/Stanley_Miller
James Watson1953 · American biologist (1928–2025) (placed at Chicago)Known works: The Double Helix, Molecular Biology of the Gene. 1953: James Watson , Francis Crick , Maurice Wilkins and Rosalind Franklin : helical structure of DNA , basis for molecular biologyhttps://en.wikipedia.org/wiki/James_Watson
Chien-Shiung Wu1957 · Chinese-American physicist (1912–1997) (placed at Taicang)Known works: Non-Conservation of Parity. 1957: Chien Shiung Wu : demonstrated that parity , and thus charge conjugation and time-reversals , are violated for weak interactionshttps://en.wikipedia.org/wiki/Chien-Shiung_Wu
NASA1958 · American space and aeronautics agency2020: NASA and SOFIA (Stratospheric Observatory for Infrared Astronomy) discover about 350 mL of surface water in one of the Moon's largest visible craters.https://en.wikipedia.org/wiki/NASA
Lawrence Morley1963 · Canadian geophysicist (1920–2013) (placed at Toronto)1963: Lawrence Morley , Fred Vine , and Drummond Matthews : Paleomagnetic stripes in ocean crust as evidence of plate tectonics ( Vine–Matthews–Morley hypothesis ).https://en.wikipedia.org/wiki/Lawrence_Morley
Arno Allan Penzias1964 · American physicist (1933–2024) (placed at Munich)Known works: cosmic microwave background. 1964: Arno Penzias and Robert Woodrow Wilson : detection of CMBR providing experimental evidence for the Big Banghttps://en.wikipedia.org/wiki/Arno_Allan_Penzias
James H. Ellis1970 · British engineer and cryptographer (1924–1997) (placed at Cheshire)1970: James H. Ellis proposed the possibility of "non-secret encryption", more commonly termed public-key cryptography , a concept that would be implemented by his GCHQ colleague Clifford Cocks in 1973, in what would become known as the RSA algorithm, with key exchange added by a third colleague Malhttps://en.wikipedia.org/wiki/James_H._Ellis
Place cell1971 · Place-activated hippocampus cells found in some mammals (placed at New York City (where John O'Keefe was born))Invented or discovered by: John O'Keefe. 1971: Place cells in the brain are discovered by John O'Keefehttps://en.wikipedia.org/wiki/Place_cell
Aleksander Wolszczan1992 · 20th and 21st-century Polish astronomer (placed at Szczecinek)1992: Aleksander Wolszczan and Dale Frail observe the first pulsar planets (this was the first confirmed discovery of planets outside the Solar System)https://en.wikipedia.org/wiki/Aleksander_Wolszczan
Andrew Wiles1994 · British mathematician who proved Fermat's Last Theorem (placed at Cambridge)Known works: Modular Elliptic Curves and Fermat's Last Theorem. 1994: Andrew Wiles proves Fermat's Last Theoremhttps://en.wikipedia.org/wiki/Andrew_Wiles
Eric Allin Cornell1995 · American physicist (placed at Palo Alto)1995: Eric Cornell , Carl Wieman and Wolfgang Ketterle attained the first Bose-Einstein Condensate with atomic gases, so called fifth state of matter at an extremely low temperature.https://en.wikipedia.org/wiki/Eric_Allin_Cornell
Michel Mayor1995 · Swiss astrophysicist & Nobel laureate of Physics (placed at Lausanne)1995: Michel Mayor and Didier Queloz definitively observe the first extrasolar planet around a main sequence starhttps://en.wikipedia.org/wiki/Michel_Mayor
Raymond Davis Jr.2002 · American scientist (1914–2006) (placed at Washington, D.C.)2002: – Raymond Davis Jr. and Masatoshi Koshiba detect transformations of different types of neutrinos , demonstrating that they have mass.https://en.wikipedia.org/wiki/Raymond_Davis_Jr.
Grigori Perelman2003 · Russian mathematician (born 1966) (placed at Saint Petersburg)Known works: Poincaré conjecture, geometrization conjecture, soul theorem, The entropy formula for the Ricci flow and its geometric applications, Ricci flow with surgery on three-manifolds, Finite extinction time for the solutions to the Ricci flow on certain three-manifolds. 2003: Grigori Perelman https://en.wikipedia.org/wiki/Grigori_Perelman
Andre Geim2004 · Dutch-British physicist (born 1958) (placed at Sochi)2004: Andre Geim and Konstantin Novoselov isolated graphene , a monolayer of carbon atoms, and studied its quantum electrical properties.https://en.wikipedia.org/wiki/Andre_Geim
Grid cell2005 · Type of neuron (placed at Ålesund Municipality (where Edvard Moser was born))Invented or discovered by: Edvard Moser, May-Britt Moser. 2005: Grid cells in the brain are discovered by Edvard Moser and May-Britt Moser .https://en.wikipedia.org/wiki/Grid_cell
Higgs boson2012 · Elementary particle involved with rest mass (placed at CERN)Invented or discovered by: CERN, ATLAS experiment, CMS experiment. Discovered or invented: 2012. 2012: Higgs boson is discovered at CERN (confirmed to 99.999% certainty)https://en.wikipedia.org/wiki/Higgs_boson
LIGO2016 · Gravitational wave observatory site2016: The LIGO team detects gravitational waves from a black hole mergerhttps://en.wikipedia.org/wiki/LIGO