400 BCE
Greek Atomists Propose Other Worlds
Ancient Greek philosophers Leucippus and Democritus propose an infinite universe with countless worlds, some inhabited. #philosophy #astronomy
Chronological Storyline (39 Milestones)
1584 CE
Giordano Bruno Advocates Infinite Worlds
Italian philosopher Giordano Bruno argues for an infinite universe with many inhabited worlds, challenging geocentric views. #philosophy #astronomy
By Unknown author - https://wellcomeimages.org/indexplus/obf_images/bc/3d/265d1be073eb34224006d0d35b02.jpg Gallery: https://wellcomeimages.org/indexplus/image/L0015152.html Wellcome Collection gallery (2018-04-01): https://wellcomecollection.org/works/qgt4dt8k CC-BY-4.0, CC BY 4.0, https://commons.wikimedia.org/w/index.php?curid=133537203
1687 CE
Newton's Laws Enable Orbital Calculations
Isaac Newton publishes Principia Mathematica, laying the gravitational foundation for understanding planetary systems beyond our own. #physics #astronomy
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
1855 CE
First Claims of Exoplanet Detection (Perturbations)
Captain W.S. Jacob suggests perturbations in the 70 Ophiuchi binary system indicate a planetary companion, later disproven. #astronomy #exoplanets
By Ophiuchus_constellation_map.png: Torsten Bronger derivative work: Kxx (talk) - Ophiuchus_constellation_map.png, CC BY-SA 3.0, https://commons.wikimedia.org/w/index.php?curid=10850776
1917 CE
First Exoplanet Evidence in Archival Data
Adriaan van Maanen's spectrum of van Maanen's star shows possible planetary debris, but not recognized at the time. #astronomy #exoplanets
By Meli thev - Own work, CC BY-SA 4.0, https://commons.wikimedia.org/w/index.php?curid=152657710
1952 CE
Otto Struve Proposes Radial Velocity Method
Otto Struve suggests that high-precision radial velocity measurements could detect exoplanets, predicting hot Jupiters. #astronomy #exoplanets
By NRAO/AUI/NSF - https://public.nrao.edu/gallery/otto-struve/, CC BY 4.0, https://commons.wikimedia.org/w/index.php?curid=169657223
1961 CE
Drake Equation Formulated
Frank Drake develops the Drake equation to estimate the number of communicative civilizations in the Milky Way. #astrobiology #seti
By NRAO/AUI/NSF - https://public.nrao.edu/gallery/frank-drake/, CC BY 4.0, https://commons.wikimedia.org/w/index.php?curid=169654646
1963 CE
First Pulsar Planet Claim (Disproven)
A planet is claimed around the pulsar PSR B0329+54, but later found to be due to timing noise. #astronomy #exoplanets
1988 CE
First Exoplanet Candidate: Gamma Cephei Ab
Campbell, Walker, and Yang detect radial velocity variations suggesting a planet around Gamma Cephei, confirmed in 2002. #astronomy #exoplanets
By User:21.Andromedae - Own work, CC BY 4.0, https://commons.wikimedia.org/w/index.php?curid=157281461
1992 CE
First Confirmed Exoplanets: Pulsar Planets
Aleksander Wolszczan and Dale Frail announce two planets orbiting pulsar PSR B1257+12, the first confirmed exoplanets. #astronomy #exoplanets
Oct 6, 1995 CE
51 Pegasi b: First Exoplanet Around Sun-like Star
Michel Mayor and Didier Queloz announce 51 Pegasi b, a hot Jupiter orbiting a Sun-like star, revolutionizing exoplanet science. #astronomy #exoplanets
By ESO/M. Kornmesser/Nick Risinger (skysurvey.org) - ESO website, CC BY 4.0, https://commons.wikimedia.org/w/index.php?curid=39719418
1999 CE
First Transiting Exoplanet: HD 209458 b
The transit of HD 209458 b is detected, allowing measurement of its radius and atmospheric composition. #astronomy #exoplanets
By Aldaron, a.k.a. Aldaron - Own work, incorporating public domain images for reference planets (see below), inspired by Thingg's size comparison, CC BY-SA 3.0, https://commons.wikimedia.org/w/index.php?curid=8903868
2001 CE
First Exoplanet Atmosphere Detected
Sodium absorption is detected in the atmosphere of HD 209458 b, marking the first direct detection of an exoplanet atmosphere. #astronomy #exoplanets
2004 CE
First Direct Image of an Exoplanet (2M1207b)
The VLT images 2M1207b, a planet orbiting a brown dwarf, the first direct image of an exoplanet. #astronomy #exoplanets
By Aldaron, a.k.a. Aldaron - Own work, incorporating public domain images for reference planets (see below), inspired by Thingg's size comparison, CC BY-SA 3.0, https://commons.wikimedia.org/w/index.php?curid=8902848
2005 CE
First Exoplanet with Water Vapor (HD 209458 b)
Spitzer Space Telescope detects water vapor in the atmosphere of HD 209458 b using infrared spectroscopy. #astronomy #exoplanets
2006 CE
First Exoplanet with Methane (HD 189733 b)
Methane is detected in the atmosphere of HD 189733 b, indicating organic chemistry. #astronomy #exoplanets
By SevenSpheres - Own work, CC BY 4.0, https://commons.wikimedia.org/w/index.php?curid=99268874
2007 CE
First Potentially Habitable Exoplanet: Gliese 581 c
Gliese 581 c is discovered in the habitable zone of its red dwarf star, sparking astrobiology interest. #astrobiology #exoplanets
By Aldaron, a.k.a. Aldaron - Own work, incorporating public domain images for reference planets (see below), CC BY-SA 3.0, https://commons.wikimedia.org/w/index.php?curid=11703403
Mar 7, 2009 CE
Kepler Space Telescope Launched
NASA's Kepler mission launches to survey the Milky Way for Earth-sized exoplanets in habitable zones. #astronomy #exoplanets
By NASA - https://science.nasa.gov/toolkits/spacecraft-icons (image link), Public domain, https://commons.wikimedia.org/w/index.php?curid=76268556
2010 CE
First Exoplanet with Carbon Dioxide (HD 189733 b)
Carbon dioxide is detected in the atmosphere of HD 189733 b, a key molecule for potential biosignatures. #astronomy #exoplanets
2011 CE
First Exoplanet in Habitable Zone of Sun-like Star: Kepler-22b
Kepler-22b is confirmed as the first exoplanet orbiting in the habitable zone of a Sun-like star. #astronomy #exoplanets
By NASA/Ames/JPL-Caltech - http://kepler.nasa.gov/news/nasakeplernews/index.cfm?FuseAction=ShowNews&NewsID=165, Public domain, https://commons.wikimedia.org/w/index.php?curid=24187911
2012 CE
First Exoplanet with Water Vapor in Habitable Zone (GJ 1214 b)
GJ 1214 b is found to have a water-rich atmosphere, though too hot for life. #astrobiology #exoplanets
By Aldaron, a.k.a. Aldaron - Own work, incorporating public domain images for reference planets (see below), inspired by Thingg's size comparison, CC BY-SA 3.0, https://commons.wikimedia.org/w/index.php?curid=8854174
2013 CE
Kepler-78b: First Earth-sized Exoplanet with Known Mass and Radius
Kepler-78b is the first Earth-sized exoplanet with both mass and radius measured, but it is too hot for life. #astronomy #exoplanets
By Aldaron, a.k.a. Aldaron - Own work, incorporating public domain images for reference planets (see below), inspired by Thingg's size comparison, CC BY-SA 3.0, https://commons.wikimedia.org/w/index.php?curid=32381319
2014 CE
First Exoplanet with Water Vapor in Habitable Zone (K2-18b)
K2-18b is discovered, later found to have water vapor in its atmosphere, a super-Earth in the habitable zone. #astrobiology #exoplanets
By Illustration: NASA, ESA, CSA, Joseph Olmsted (STScI) Science: Nikku Madhusudhan (IoA) - https://webbtelescope.org/contents/media/images/2023/139/01H9R88HG8YXRMARWZ5B1YDT27, Public domain, https://commons.wikimedia.org/w/index.php?curid=137418814
2015 CE
First Exoplanet with Oxygen (HD 209458 b)
Atomic oxygen is detected in the upper atmosphere of HD 209458 b, a potential biosignature. #astronomy #exoplanets
2016 CE
Proxima Centauri b Discovered
An Earth-sized planet is found orbiting Proxima Centauri, the closest star to the Sun, in its habitable zone. #astrobiology #exoplanets
By ESO/M. Kornmesser - https://www.eso.org/public/images/ann16056a/, CC BY 4.0, https://commons.wikimedia.org/w/index.php?curid=50869082
Feb 22, 2017 CE
TRAPPIST-1 System Announced
NASA announces the TRAPPIST-1 system with seven Earth-sized planets, three in the habitable zone, a major milestone for astrobiology. #astrobiology #exoplanets
By Processing and color compositing by Nrco0e; original images by Sloan Digital Sky Survey - Own work; processed from images acquired from the SDSS DR17 archive, CC BY 4.0, https://commons.wikimedia.org/w/index.php?curid=191888700
Apr 18, 2018 CE
TESS Launched
NASA's Transiting Exoplanet Survey Satellite (TESS) launches to survey the entire sky for exoplanets around bright stars. #astronomy #exoplanets
By Orbital ATK / NASA - https://svs.gsfc.nasa.gov/vis/a010000/a012700/a012782/TESS_alone_high_res.jpg https://svs.gsfc.nasa.gov/12782, Public domain, https://commons.wikimedia.org/w/index.php?curid=108981705
2019 CE
First Exoplanet with Water Vapor in Habitable Zone (K2-18b Confirmed)
Water vapor is confirmed in the atmosphere of K2-18b, the first such detection for a planet in the habitable zone. #astrobiology #exoplanets
2020 CE
First Exoplanet with Nitrogen (GJ 1132 b)
Nitrogen is detected in the atmosphere of GJ 1132 b, a key element for life. #astrobiology #exoplanets
By Aldaron, a.k.a. Aldaron - Own work, incorporating public domain images for reference planets (see below), inspired by Thingg's size comparison, CC BY-SA 3.0, https://commons.wikimedia.org/w/index.php?curid=44973197
Dec 25, 2021 CE
James Webb Space Telescope Launched
JWST launches, capable of characterizing exoplanet atmospheres in unprecedented detail, including potential biosignatures. #astronomy #exoplanets
By NASA - https://www.jwst.nasa.gov/content/webbLaunch/whereIsWebb.html, Public domain, https://commons.wikimedia.org/w/index.php?curid=114125719
2022 CE
JWST Detects Carbon Dioxide in Exoplanet Atmosphere
JWST detects carbon dioxide in the atmosphere of WASP-39b, demonstrating its capability for detailed atmospheric studies. #astronomy #exoplanets
By NASA, ESA, CSA, J. Olmsted (STScI) - Illustration (Artist’s Impression) of WASP-39 b and Its Star, CC BY 4.0, https://commons.wikimedia.org/w/index.php?curid=125907007
2023 CE
First Exoplanet with Potential Biosignature (K2-18b Methane and CO2)
JWST detects methane and carbon dioxide in K2-18b's atmosphere, consistent with a habitable ocean world. #astrobiology #exoplanets
2023 CE
JWST Detects Water Vapor in Terrestrial Exoplanet Atmosphere
JWST detects water vapor in the atmosphere of GJ 486 b, a rocky exoplanet, though possibly from starspots. #astrobiology #exoplanets
By Martin Vargic / Halcyon Maps Utilizing public domain imagery from NASA - https://www.halcyonmaps.com/exoplanet-systems-visualized/, CC BY 3.0, https://commons.wikimedia.org/w/index.php?curid=148860640
2024 CE
PLATO Mission Approved
ESA's PLATO mission, designed to find Earth-like exoplanets around Sun-like stars, is approved for launch in 2026. #astronomy #exoplanets )
By ESA/ATG Europe - https://www.esa.int/ESA_Multimedia/Images/2023/05/Plato_key_visual, CC BY-SA 4.0, https://commons.wikimedia.org/w/index.php?curid=175139220
2025 CE
Nancy Grace Roman Space Telescope Launch
NASA's Roman telescope launches with a coronagraph to directly image exoplanets and characterize their atmospheres. #astronomy #exoplanets
By NASA - https://roman.gsfc.nasa.gov/gallery-spacecraftillustrations.html, Public domain, https://commons.wikimedia.org/w/index.php?curid=136706293
2026 CE
Ariel Mission Launch
ESA's Ariel mission launches to study the atmospheres of a large sample of exoplanets. #astronomy #exoplanets )
2029 CE
LUVOIR Concept Study
NASA's LUVOIR concept study proposes a large UV-optical-IR telescope capable of directly imaging Earth-like exoplanets and searching for biosignatures. #astrobiology #exoplanets
By Andrew Jones - https://asd.gsfc.nasa.gov/luvoir/, Public domain, https://commons.wikimedia.org/w/index.php?curid=81667752
2030 CE
HabEx Concept Study
NASA's Habitable Exoplanet Observatory (HabEx) concept study aims to directly image and characterize habitable exoplanets. #astrobiology #exoplanets
By NASA - https://www.jpl.nasa.gov/habex/pdf/HabEx-Final-Report-Public-Release.pdf, Public domain, https://commons.wikimedia.org/w/index.php?curid=82015587
2035 CE
First Direct Image of an Earth-like Exoplanet (Projected)
Future telescopes like LUVOIR or HabEx are expected to capture the first direct image of an Earth-like exoplanet, revolutionizing astrobiology. #astrobiology #exoplanets