350 BCE
Aristotle's Theory of Gravity
Aristotle proposes that objects fall at speeds proportional to their weight, laying early groundwork for gravitational theory. #physics #history
Chronological Storyline (37 Milestones)
Jul 5, 1687 CE
Newton's Principia Mathematica
Isaac Newton publishes Philosophiæ Naturalis Principia Mathematica, introducing the law of universal gravitation and laying the foundation for classical gravity. #physics #science
By The original uploader was Zhaladshar at English Wikisource. - Transferred from en.wikisource to Commons. (previous image from another copy) Internet Archive (current image from the Bern Dibner copy), Public domain, https://commons.wikimedia.org/w/index.php?curid=2681838
Feb 3, 1851 CE
Foucault Pendulum Demonstrates Earth's Rotation
Léon Foucault publicly demonstrates his pendulum, providing direct evidence of Earth's rotation and highlighting the role of reference frames in gravity. #physics #experiment
By Rémih - Own work, CC BY-SA 3.0, https://commons.wikimedia.org/w/index.php?curid=19383691
Jul 1, 1887 CE
Michelson-Morley Experiment
Albert Michelson and Edward Morley perform a precision interferometry experiment to detect the luminiferous aether, returning a null result that later influences special relativity and interferometry techniques. #physics #interferometry
By Case Western Reserve University - http://www.cellularuniverse.org/AA2MM_Aether.htm, Public domain, https://commons.wikimedia.org/w/index.php?curid=48697725
Sep 26, 1905 CE
Einstein's Special Relativity
Albert Einstein publishes his paper on special relativity, establishing the speed of light as a constant and the relationship between space and time. #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
Nov 25, 1915 CE
Einstein's General Relativity
Albert Einstein presents the final form of general relativity, describing gravity as the curvature of spacetime. #physics #relativity
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
Jun 1, 1916 CE
Einstein Predicts Gravitational Waves
Albert Einstein publishes a paper predicting the existence of gravitational waves as ripples in spacetime, a direct consequence of general relativity. #physics #gravitationalwaves
By Simulating eXtreme Spacetimes Collaboration/Canadian Institute for Theoretical Astrophysics/SciNet - http://www.black-holes.org/gw150914 (see https://www.youtube.com/watch?v=c-2XIuNFgD0), CC BY-SA 4.0, https://commons.wikimedia.org/w/index.php?curid=46983496
1936 CE
Einstein and Rosen on Plane Gravitational Waves
Einstein and Nathan Rosen publish a paper arguing gravitational waves might be artifacts of the coordinate system, later resolved as real physical waves. #physics #gravitationalwaves
Jan 1, 1957 CE
Chapel Hill Conference on Gravitational Waves
Physicists including Richard Feynman and John Wheeler discuss gravitational waves, with Feynman's 'sticky bead' argument demonstrating they carry energy. #physics #history
1960 CE
Pirani's Paper on Gravitational Wave Detection
Felix Pirani publishes a paper describing how gravitational waves could be detected by measuring the strain between free masses, laying groundwork for interferometry. #physics #gravitationalwaves
1962 CE
Bondi's Work on Gravitational Wave Energy
Hermann Bondi publishes a paper confirming that gravitational waves carry energy, resolving theoretical debates. #physics #gravitationalwaves
Nov 1, 1967 CE
Discovery of the First Pulsar
Jocelyn Bell Burnell and Antony Hewish discover the first pulsar, a rapidly rotating neutron star that later becomes a key source for gravitational wave studies. #astronomy #physics
By NASA/CXC/SAO (X-Ray); NASA/JPL-Caltech (Infrared) - http://www.nasa.gov/sites/default/files/pia18848-wisefacepalm.jpg, Public domain, https://commons.wikimedia.org/w/index.php?curid=36363158
1969 CE
Weber Claims Detection of Gravitational Waves
Joseph Weber announces detection of gravitational waves using his resonant bar detectors, but later experiments fail to replicate the results. #physics #controversy
By US Navy - http://www.usna.com/NC/History/ClassOf1940/images/JosephWeber.jpg, Public domain, https://commons.wikimedia.org/w/index.php?curid=17701824
Jul 1, 1974 CE
Discovery of Binary Pulsar PSR B1913+16
Russell Hulse and Joseph Taylor discover a binary pulsar system, providing an ideal laboratory for testing general relativity and indirect evidence of gravitational waves. #astronomy #physics
1979 CE
Orbital Decay Measurement Confirms Gravitational Waves
Hulse and Taylor publish precise measurements of the binary pulsar's orbital decay, matching the prediction of energy loss via gravitational waves. #physics #gravitationalwaves
1983 CE
Concept for Laser Interferometer Gravitational-Wave Observatory (LIGO)
Scientists including Rainer Weiss propose building a large-scale laser interferometer to directly detect gravitational waves, leading to the LIGO project. #physics #interferometry
By Amber Stuver - Own work, CC BY-SA 4.0, https://commons.wikimedia.org/w/index.php?curid=46993713
1990 CE
LIGO Project Approved by NSF
The U.S. National Science Foundation approves funding for the construction of LIGO, with two observatories in Hanford, Washington and Livingston, Louisiana. #science #funding
1994 CE
Construction Begins on LIGO Hanford
Ground is broken for the LIGO Hanford Observatory in Washington state, one of two LIGO sites. #engineering #physics
1997 CE
LIGO Livingston Observatory Construction
Construction of the LIGO Livingston Observatory in Louisiana begins, completing the dual-site detector network. #engineering #physics
Aug 23, 2002 CE
LIGO Begins First Science Run
LIGO begins its inaugural science run (S1) at initial sensitivity, collecting data but not yet detecting gravitational waves. #physics #experiment
Nov 1, 2005 CE
Advanced LIGO Design Finalized
The design for Advanced LIGO, a major upgrade to increase sensitivity by a factor of 10, is completed and construction begins. #physics #engineering
May 1, 2007 CE
Virgo Detector Begins Operation
The Virgo interferometer in Cascina, Italy, starts its first scientific run, joining the global network for gravitational wave detection. #physics #Europe
By The Virgo collaboration, CC0, https://commons.wikimedia.org/w/index.php?curid=45342143
2010 CE
Advanced LIGO Construction Starts
Construction of Advanced LIGO begins, involving major upgrades to the laser, optics, and vacuum systems to achieve higher sensitivity. #physics #engineering
Sep 14, 2015 CE
First Direct Detection of Gravitational Waves (GW150914)
LIGO detects gravitational waves from a binary black hole merger about 1.3 billion light-years away, confirming Einstein's 1916 prediction and launching gravitational wave astronomy. #physics #gravitationalwaves #breakthrough
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
Feb 11, 2016 CE
LIGO Announces Detection of Gravitational Waves
The LIGO collaboration publicly announces the first direct detection of gravitational waves, making global headlines and earning the researchers the 2017 Nobel Prize in Physics. #physics #Nobel
Jan 4, 2017 CE
Advanced LIGO Achieves Design Sensitivity
Advanced LIGO reaches its design sensitivity, enabling more frequent detections of gravitational waves. #physics #engineering
Aug 14, 2017 CE
First Triple-Detector Observation (GW170814)
LIGO and Virgo together detect a gravitational wave signal from a binary black hole merger, marking the first time three detectors improve sky localization. #physics #gravitationalwaves
By LIGO Scientific Collaboration and Virgo Collaboration - https://doi.org/10.1103/PhysRevLett.119.141101 (GW170814: A Three-Detector Observation of Gravitational Waves from a Binary Black Hole Coalescence, Abbott et al., Physical Review Letters) This plot was created with Matplotlib., CC BY-SA 4.0, https://commons.wikimedia.org/w/index.php?curid=62823015
Oct 16, 2017 CE
First Multimessenger Observation (GW170817)
LIGO and Virgo detect gravitational waves from a neutron star merger, GW170817, followed by observations across the electromagnetic spectrum, ushering in multimessenger astronomy. #astronomy #gravitationalwaves #multimessenger
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 1, 2018 CE
Virgo Joins LIGO for Third Observing Run
The Virgo detector actively participates in the third observing run (O3) alongside LIGO, enhancing sky localization and detection confidence. #physics #collaboration
Nov 1, 2019 CE
LIGO-Virgo Catalog of Gravitational Wave Events
The LIGO-Virgo collaboration releases GWTC-2, a catalog of 39 gravitational wave events from the first half of O3, expanding the known population. #physics #catalog
By Ligo.gif: The original uploader was MOBle at English Wikipedia. derivative work: Malyszkz language-switch: Rothwild Chinese: Yinweichen German: Mfb Macedonian: B. Jankuloski Russian: Эээ Polish: Mbejger Ukrainian: Kirsim - Own work based on: Ligo.gif:, Public domain, https://commons.wikimedia.org/w/index.php?curid=18325956
Feb 25, 2020 CE
KAGRA Detector Begins Operation
The Japanese Kamioka Gravitational Wave Detector (KAGRA) starts its first observation run, becoming part of the global detector network with unique underground and cryogenic features. #physics #Japan
By Christopher Berry - http://cplberry.com/2015/07/26/whats-up-doc/, CC BY-SA 4.0, https://commons.wikimedia.org/w/index.php?curid=45370733
Oct 1, 2021 CE
LIGO-Virgo-KAGRA Collaboration Formed
The three major gravitational wave detectors formalize operations as a single collaboration, LIGO-Virgo-KAGRA, to coordinate observing runs and data analysis. #physics #collaboration
Nov 1, 2022 CE
GWTC-3 Catalog Released
The LIGO-Virgo-KAGRA collaboration publishes GWTC-3, adding 35 new gravitational wave events from the second half of O3, totaling over 90 confirmed detections. #physics #catalog
Jun 29, 2023 CE
NANOGrav Finds Evidence of Gravitational Wave Background
The North American Nanohertz Observatory for Gravitational Waves (NANOGrav) announces evidence for a stochastic gravitational wave background using pulsar timing arrays, opening a new window. #astronomy #gravitationalwaves #pulsartiming
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
2023 CE
LIGO India Project Approved
The Indian government approves the construction of LIGO-India, a third LIGO detector that will significantly improve sky localization and science reach. #physics #India
Mar 1, 2024 CE
LIGO O4 Observing Run Begins
LIGO starts its fourth observing run (O4) with improved sensitivity, aiming to detect dozens more gravitational wave events. #physics #experiment
2025 CE
Einstein Telescope Conceptual Design
The European Einstein Telescope, a proposed third-generation gravitational wave observatory, completes its conceptual design phase, promising even greater sensitivity. #physics #future