490 BCE
Zeno of Elea Formulates Paradoxes of Motion
Zeno's paradoxes, such as Achilles and the Tortoise, highlight problems with infinity and motion that later influence concepts of spacetime. #philosophy #physics
Chronological Storyline (42 Milestones)
300 BCE
Euclid Writes 'Elements'
Euclid's 'Elements' establishes the geometric axioms underlying later spacetime geometry. #mathematics #geometry
By University of Pennsylvania Museum of Archaeology and Anthropology - https://openn.library.upenn.edu/Data/0016/html/e2748.html, CC BY-SA 4.0, https://commons.wikimedia.org/w/index.php?curid=169166171
240 CE
Hippolyte's Refutation of All Heresies Mentions Early Light Speed Ideas
Early Christian writer Hippolyte notes Empedocles' idea that light takes time to travel, a precursor to speed of light concepts. #physics #history
By Dobroš © Dana Stehlíková - Own work, CC BY-SA 4.0, https://commons.wikimedia.org/w/index.php?curid=170314912
1021 CE
Ibn al-Haytham Discusses Light and Time
Ibn al-Haytham's 'Book of Optics' suggests light travels at a finite speed, influencing later wave theory. #optics #physics #islamicgoldenage
By Ibn al-Haytham, Vitello, Friedrich Risner - University of Oklahoma History of Science Collections et BnF Gallica : http://gallica.bnf.fr/ark:/12148/bpt6k312873d.r=Haytham?rk=407727;2, Public domain, https://commons.wikimedia.org/w/index.php?curid=48189707
1632 CE
Galileo Discusses Relativity of Motion
Galileo's 'Dialogue Concerning the Two Chief World Systems' articulates the principle of relativity for uniform motion. #physics #relativity
By Giovanni Battista Landini - http://moro.imss.fi.it/lettura/LetturaWEB.DLL?AZIONE=IMG&TESTO=E_U&PARAM=07-23-tit.jpg and http://moro.imss.fi.it/lettura/LetturaWEB.DLL?AZIONE=IMG&TESTO=E_U&PARAM=07-25-tit.jpg Transferred from en.wikipedia to Commons by User:Lijealso using CommonsHelper., Public domain, https://commons.wikimedia.org/w/index.php?curid=5289735
Nov 22, 1676 CE
Rømer Measures Speed of Light
Danish astronomer Ole Rømer uses Jupiter's moons to estimate the finite speed of light, a key constant for relativity. #astronomy #physics
By Jacob Coning - Farvereproduktioner efter 20 portrætter af berømte danske mænd (København 1943), Public domain, https://commons.wikimedia.org/w/index.php?curid=33262775
1728 CE
Bradley Discovers Stellar Aberration
James Bradley's observation of stellar aberration provides direct evidence of Earth's motion and finite light speed. #astronomy #physics
By BlankAxolotl - inkscape, CC BY-SA 3.0, https://commons.wikimedia.org/w/index.php?curid=46795372
1849 CE
Fizeau Measures Speed of Light on Earth
Hippolyte Fizeau uses a rotating toothed wheel to measure the speed of light in air, refining the constant. #physics #experiment
By Éleuthère Mascart - https://archive.org/details/traitdoptique02mascgoog, p. 103, Public domain, https://commons.wikimedia.org/w/index.php?curid=10965303
1851 CE
Foucault's Pendulum and Gyroscope Experiments
Léon Foucault demonstrates Earth's rotation with a pendulum, complementing relativity principles. #physics #experiment
By Rémih - Own work, CC BY-SA 3.0, https://commons.wikimedia.org/w/index.php?curid=19383691
1868 CE
Fizeau's Water Tube Experiment
Fizeau measures light speed in moving water, revealing partial drag of aether by water, a precursor to special relativity. #physics #optics
Jul 1, 1887 CE
Michelson–Morley Experiment
Michelson and Morley fail to detect the aether wind, challenging Newtonian physics and leading to special relativity. #physics #experiment
By Case Western Reserve University - http://www.cellularuniverse.org/AA2MM_Aether.htm, Public domain, https://commons.wikimedia.org/w/index.php?curid=48697725
1889 CE
FitzGerald–Lorentz Contraction Hypothesis
George FitzGerald and Hendrik Lorentz independently propose length contraction to explain the null result of Michelson–Morley. #physics #relativity
By Thierry Dugnolle - Own work, CC BY-SA 4.0, https://commons.wikimedia.org/w/index.php?curid=90983525
1895 CE
Lorentz Publishes Local Time Concept
Hendrik Lorentz introduces 'local time' to explain electrodynamics of moving bodies, a key step toward special relativity. #physics #electrodynamics
By Unknown author - http://hdl.handle.net/10648/ad887254-d0b4-102d-bcf8-003048976d84, PDM-owner, https://commons.wikimedia.org/w/index.php?curid=144534263
1899 CE
Lorentz Transformations Formulated
Lorentz derives equations for transforming space and time coordinates between inertial frames, crucial for special relativity. #physics #mathematics
By The website of the Royal Library shows a picture from the same photosession that is attributed to Museum Boerhaave. The website of the Museum states "vrij beschikbaar voor publicatie" (freely available for publication). - http://th.physik.uni-frankfurt.de/~jr/physpictheo.html (moved from de:Bild:Hendrik Antoon Lorentz.jpg), Public domain, https://commons.wikimedia.org/w/index.php?curid=224998
1900 CE
Poincaré Discusses Principle of Relativity
Henri Poincaré gives a lecture at Paris Expo on the relativity of motion and the impossibility of detecting absolute motion. #physics #history
By Unknown author - Popular Science Monthly Volume 82, Public domain, https://commons.wikimedia.org/w/index.php?curid=20644432
1904 CE
Larmor Formulates Time Dilation
Joseph Larmor discovers time dilation in the context of electron motion, a key relativistic effect. #physics #electrodynamics
Jun 30, 1905 CE
Einstein Publishes 'On the Electrodynamics of Moving Bodies'
Albert Einstein introduces special relativity, abolishing aether and postulating the constancy of light speed. #physics #relativity
By Lucien Chavan [1] (1868 - 1942), a friend of Einstein's when he was living in Berne. - Cropped from original at the The Albert Einstein Archives, The Hebrew University of Jerusalem., Public domain, https://commons.wikimedia.org/w/index.php?curid=16699199
Sep 27, 1905 CE
Einstein Derives Mass–Energy Equivalence
In a follow-up paper, Einstein presents E=mc², establishing the equivalence of mass and energy. #physics #relativity
By NASA and The Hubble Heritage Team (STScI/AURA) - HubbleSite: gallery, release., Public domain, https://commons.wikimedia.org/w/index.php?curid=102873
1907 CE
Minkowski Introduces Spacetime
Hermann Minkowski reformulates special relativity as a four-dimensional spacetime geometry, unifying space and time. #physics #mathematics
By Hermann Minkowski - scan from original book, Public domain, https://commons.wikimedia.org/w/index.php?curid=2956997
1908 CE
Bucherer Experiment Confirms Relativistic Mass Increase
Alfred Bucherer's experiment with cathode rays verifies the relativistic mass increase predicted by Lorentz and Einstein. #physics #experiment
By Stigmatella aurantiaca - Own work, CC BY-SA 3.0, https://commons.wikimedia.org/w/index.php?curid=20607088
1911 CE
Langevin's Twin Paradox Thought Experiment
Paul Langevin describes the twin paradox, illustrating time dilation due to relative motion. #physics #relativity
By Robert Markowitz - https://www.flickr.com/photos/nasa2explore/16335632852/, Public domain, https://commons.wikimedia.org/w/index.php?curid=37967329
1915 CE
Einstein Publishes General Relativity
Albert Einstein completes general relativity, extending special relativity to gravitation and curved spacetime. #physics #gravity
By Simulating eXtreme Spacetimes Lensing (SXS) - https://www.ligo.caltech.edu/video/ligo20160211v3 (video link); see also http://www.black-holes.org/gw150914, CC BY-SA 4.0, https://commons.wikimedia.org/w/index.php?curid=46994894
1916 CE
Schwarzschild Solves Einstein's Equations
Karl Schwarzschild finds the first exact solution to Einstein's field equations, predicting black holes. #physics #astrophysics
1917 CE
de Sitter Discovers Static Einstein–de Sitter Universe
Willem de Sitter finds a solution with no matter, leading to the expanding universe concept. #cosmology #physics
By NASA / WMAP Science Team - http://map.gsfc.nasa.gov/media/121238/ilc_9yr_moll4096.png, Public domain, https://commons.wikimedia.org/w/index.php?curid=23285693
May 29, 1919 CE
Eddington Expedition Confirms Light Bending
Arthur Eddington's solar eclipse observation confirms general relativity's prediction of light deflection by gravity. #astronomy #physics
By ESO/Landessternwarte Heidelberg-Königstuhl/F. W. Dyson, A. S. Eddington, & C. Davidson - https://www.eso.org/public/images/potw1926a/, CC BY 4.0, https://commons.wikimedia.org/w/index.php?curid=80091497
1921 CE
Sagnac Effect Measured
Georges Sagnac detects the effect of rotation on light interference, demonstrating relativity in rotating frames. #physics #optics
By Krishnavedala - Own work, CC BY-SA 3.0, https://commons.wikimedia.org/w/index.php?curid=36958913
1927 CE
Weyl's Gauge Theory
Hermann Weyl attempts to unify electromagnetism and gravity by proposing gauge invariance, influencing later quantum field theory. #physics #mathematics
By Joel Holdsworth (Joelholdsworth) - Non-Derived SVG of Radiate gluon.png, originally the work of SilverStar at Feynmann-diagram-gluon-radiation.svg, updated by joelholdsworth., Public domain, https://commons.wikimedia.org/w/index.php?curid=1764161
1932 CE
Kennedy–Thorndike Experiment
Kennedy and Thorndike perform an improved Michelson–Morley experiment using an asymmetric interferometer, confirming time dilation. #physics #experiment
By User:Stigmatella aurantiaca - Own work by the original uploader, CC BY-SA 3.0, https://commons.wikimedia.org/w/index.php?curid=20409365
1938 CE
Ives–Stilwell Experiment Tests Time Dilation
Herbert Ives and G.R. Stilwell measure the relativistic Doppler shift of hydrogen ions, confirming time dilation. #physics #experiment
By Prokaryotic Caspase Homolog - Own work, CC BY-SA 4.0, https://commons.wikimedia.org/w/index.php?curid=134901330
1964 CE
Discovery of Cosmic Microwave Background Radiation
Penzias and Wilson discover CMB, strong evidence for the Big Bang and expanding spacetime. #cosmology #astronomy
By ESA and the Planck Collaboration - Cosmic Microwave Background, CC BY 4.0, https://commons.wikimedia.org/w/index.php?curid=130789180
1971 CE
Hafele–Keating Experiment Tests Time Dilation
Atomic clocks flown on commercial airliners show time dilation predicted by special and general relativity. #physics #experiment
By Binarysequence - Own work, CC BY-SA 3.0, https://commons.wikimedia.org/w/index.php?curid=24592511
1974 CE
Hulse–Taylor Binary Pulsar Discovered
Russell Hulse and Joseph Taylor discover a binary pulsar whose orbital decay matches gravitational wave predictions of general relativity. #astrophysics #physics
1977 CE
Gravity Probe A Tests Time Dilation
A hydrogen maser launched on a rocket confirms gravitational time dilation to high precision. #physics #experiment
By Benjamin Crowell - This image has been extracted from another file, CC BY-SA 4.0, https://commons.wikimedia.org/w/index.php?curid=77750634
1983 CE
International System Redefines Metre Using Light Speed
The metre is redefined as the distance light travels in 1/299,792,458 second, fixing the speed of light. #physics #measurement
By LucasVB - Own work, Public domain, https://commons.wikimedia.org/w/index.php?curid=20513669
1992 CE
COBE Maps CMB Anisotropies
NASA's COBE satellite detects tiny temperature fluctuations in the cosmic microwave background, supporting inflation and spacetime geometry. #cosmology #space
By NASA - https://science.nasa.gov/toolkits/spacecraft-icons (image link), Public domain, https://commons.wikimedia.org/w/index.php?curid=58072784
1998 CE
Discovery of Dark Energy from Supernovae
Observations of distant Type Ia supernovae reveal the accelerating expansion of the universe, implying a cosmological constant. #cosmology #astrophysics
2003 CE
WMAP Provides Precision Cosmology
NASA's Wilkinson Microwave Anisotropy Probe measures CMB with high precision, constraining spacetime curvature and age of universe. #cosmology #space
By NASA / WMAP Science Team - [1]; converted from the high-resolution TIFF version to a JPEG, Public domain, https://commons.wikimedia.org/w/index.php?curid=3944989
2011 CE
Gravity Probe B Confirms Frame-Dragging
NASA's Gravity Probe B experiment measures geodetic precession and frame-dragging, verifying general relativity predictions. #physics #space
By NASA/MSFC - http://www.nasa.gov/mission_pages/gpb/gpb_013.html, Public domain, https://commons.wikimedia.org/w/index.php?curid=5532645
Sep 14, 2015 CE
LIGO Detects Gravitational Waves
First direct observation of gravitational waves from merging black holes, confirming a key prediction of general relativity. #astrophysics #physics
By B. P. Abbott et al. (LIGO Scientific Collaboration and Virgo Collaboration) — full list at the end of the article - http://physics.aps.org/featured-article-pdf/10.1103/PhysRevLett.116.061102 . See also the associated Jupyter notebook., CC BY 3.0, https://commons.wikimedia.org/w/index.php?curid=46987868
Oct 16, 2017 CE
Neutron Star Merger Observed in Light and Gravitational Waves
LIGO and telescopes observe GW170817, a neutron star merger, linking gravity to electromagnetic signals. #astronomy #physics
By LIGO Scientific Collaboration and Virgo Collaboration - https://journals.aps.org/prl/abstract/10.1103/PhysRevLett.119.161101 This W3C-unspecified plot was created with Matplotlib., CC BY-SA 4.0, https://commons.wikimedia.org/w/index.php?curid=63455773
Apr 10, 2019 CE
Event Horizon Telescope Images Black Hole
First direct image of a black hole's shadow, confirming spacetime curvature predictions of general relativity. #astrophysics #space
By D. Marrone/UofA - Event Horizon Telescope Collaboration, CC BY 4.0, https://commons.wikimedia.org/w/index.php?curid=133002860
2023 CE
NANOGrav Detects Gravitational Wave Background
Pulsar timing arrays reveal low-frequency gravitational wave background from supermassive black hole mergers. #astrophysics #physics
By NANOGrav - https://nanograv.org/press/image-gallery (info about licence can be found here: https://nanograv.org/resources/press), CC BY 4.0, https://commons.wikimedia.org/w/index.php?curid=171055295