Encyclopedia/1. The Cosmos & The Natural World/3. Astronomy & Planetary Science • Curated by Admin Timeline.sg
This timeline traces the key discoveries and milestones in exoplanet and astrobiology research, from ancient philosophical speculations about other worlds to the modern era of space telescopes and biosignature detection.
Chronological Storyline (37 Milestones)
400 BCE
Democritus Proposes Infinite Worlds
Greek philosopher Democritus proposes the existence of infinite worlds, some inhabited, laying early philosophical foundations for exoplanet and astrobiology concepts. #philosophy #astronomy
Democritus Proposes Infinite Worlds By user:shakko - Own work, CC BY-SA 3.0, https://commons.wikimedia.org/w/index.php?curid=5535206
1584 CE
Giordano Bruno Advocates for Other Suns
Italian philosopher Giordano Bruno suggests that stars are other suns with their own planets, possibly inhabited, for which he was later burned at the stake. #astronomy #philosophy
Giordano Bruno Advocates for Other Suns 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
1855 CE
First Claim of an Exoplanet Detection
Captain W.S. Jacob at the Madras Observatory reports anomalies in the orbit of 70 Ophiuchi, suggesting a planetary companion, though later disproven. #astronomy #exoplanets
First Claim of an Exoplanet Detection 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
1916 CE
Barnard's Star Discovered
E.E. Barnard discovers Barnard's Star, a nearby red dwarf that later becomes a target for exoplanet searches. #astronomy #stars
Barnard's Star Discovered By Steve Quirk - https://web.archive.org/web/20080721013827/http://my.hwy.com.au/~sjquirk/images/film/barnard.html, Public domain, https://commons.wikimedia.org/w/index.php?curid=3160016
1952 CE
Otto Struve Proposes Exoplanet Detection Methods
Astronomer Otto Struve suggests using radial velocity and transit methods to detect exoplanets, pioneering concepts later realized. #astronomy #exoplanets
Otto Struve Proposes Exoplanet Detection Methods By NRAO/AUI/NSF - https://public.nrao.edu/gallery/otto-struve/, CC BY 4.0, https://commons.wikimedia.org/w/index.php?curid=169657223
1960 CE
Project Ozma: First SETI Search
Frank Drake conducts Project Ozma, the first modern search for extraterrestrial intelligence, targeting Tau Ceti and Epsilon Eridani. #SETI #astrobiology
Project Ozma: First SETI Search By NRAO/AUI/NSF - https://public.nrao.edu/gallery/father-of-seti-with-setis-first-telescope/, CC BY 4.0, https://commons.wikimedia.org/w/index.php?curid=169653316
1961 CE
Drake Equation Formulated
Frank Drake formulates the Drake Equation to estimate the number of communicative civilizations in the Milky Way, a key concept in astrobiology. #astrobiology #SETI
Drake Equation Formulated 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 Candidate
A planet around a pulsar is proposed but later retracted; the first exoplanet detection remains controversial. #astronomy #exoplanets
First Pulsar Planet Candidate By NASA/JPL-Caltech - https://photojournal.jpl.nasa.gov/catalog/PIA08042, Public domain, https://commons.wikimedia.org/w/index.php?curid=705149
1988 CE
First Confirmed Exoplanet Candidates
Campbell, Walker, and Yang detect radial velocity variations in Gamma Cephei, suggesting a planet, but confirmation takes years. #astronomy #exoplanets
First Confirmed Exoplanet Candidates 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 the discovery of two planets orbiting the pulsar PSR B1257+12, the first confirmed exoplanets. #astronomy #exoplanets
Oct 6, 1995 CE
51 Pegasi b: First Sun-like Star Exoplanet
Michel Mayor and Didier Queloz announce the discovery of 51 Pegasi b, a hot Jupiter orbiting a Sun-like star, revolutionizing exoplanet science. #astronomy #exoplanets
51 Pegasi b: First Sun-like Star Exoplanet By ESO/M. Kornmesser/Nick Risinger (skysurvey.org) - ESO website, CC BY 4.0, https://commons.wikimedia.org/w/index.php?curid=39719418
1996 CE
First Exoplanet in the Habitable Zone
The discovery of 70 Virginis b, though a hot Jupiter, is noted for being in the habitable zone of its star. #astronomy #exoplanets
First Exoplanet in the Habitable Zone By HeNRyKus - Own work, GPL, https://commons.wikimedia.org/w/index.php?curid=3447272
1999 CE
First Transiting Exoplanet Detected
HD 209458 b is the first exoplanet observed transiting its star, enabling atmospheric studies. #astronomy #exoplanets
First Transiting Exoplanet Detected 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 is detected in the atmosphere of HD 209458 b, the first direct detection of an exoplanet atmosphere. #astronomy #exoplanets
2003 CE
First Exoplanet Discovered by Microlensing
OGLE 2003-BLG-235/MOA 2003-BLG-53 is the first exoplanet detected via gravitational microlensing. #astronomy #exoplanets
2004 CE
First Direct Image of an Exoplanet Candidate
2M1207b is imaged directly, though its status as a planet or brown dwarf is debated. #astronomy #exoplanets
First Direct Image of an Exoplanet Candidate 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
Water vapor is detected in the atmosphere of HD 209458 b using Spitzer Space Telescope. #astronomy #exoplanets
2006 CE
First Exoplanet with a Measured Orbit
The orbital parameters of HD 209458 b are precisely measured, including its radius and mass. #astronomy #exoplanets
2007 CE
First Super-Earth in Habitable Zone
Gliese 581 c is announced as a potentially habitable super-Earth, though later found to be too hot. #astronomy #exoplanets
First Super-Earth in Habitable Zone 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
2008 CE
First Multi-Planet System Directly Imaged
HR 8799 is the first multi-planet system directly imaged, with three planets initially detected. #astronomy #exoplanets
First Multi-Planet System Directly Imaged By Image: NASA, ESA, CSA, STScI, Laurent Pueyo (STScI), William Balmer (JHU), Marshall Perrin (STScI) - HR 8799 (NIRCam Image), Public domain, https://commons.wikimedia.org/w/index.php?curid=162292518
Mar 7, 2009 CE
Kepler Space Telescope Launched
NASA's Kepler mission launches to discover Earth-sized exoplanets in the habitable zone via transit method. #astronomy #exoplanets
Kepler Space Telescope Launched 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 a Measured Day-Night Temperature
Spitzer measures temperature variations on HD 189733 b, revealing a hot day side and cooler night side. #astronomy #exoplanets
First Exoplanet with a Measured Day-Night Temperature By SevenSpheres - Own work, CC BY 4.0, https://commons.wikimedia.org/w/index.php?curid=99268874
Feb 2, 2011 CE
Kepler-10b: First Rocky Exoplanet
Kepler-10b is confirmed as the first rocky exoplanet, with a density similar to Earth's. #astronomy #exoplanets
Kepler-10b: First Rocky Exoplanet 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=12657193
Dec 5, 2011 CE
Kepler-22b: First Kepler Habitable Zone Planet
Kepler-22b is the first exoplanet confirmed by Kepler to orbit in the habitable zone of a Sun-like star. #astronomy #exoplanets
Kepler-22b: First Kepler Habitable Zone Planet 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
Alpha Centauri Bb Claimed
A planet is claimed around Alpha Centauri B, later retracted due to data artifacts. #astronomy #exoplanets
Alpha Centauri Bb Claimed By ESO/L. Calçada/N. Risinger - ESO, CC BY 4.0, https://commons.wikimedia.org/w/index.php?curid=23163877
2013 CE
First Exoplanet with Water Vapor in Habitable Zone
Water vapor is detected in the atmosphere of Kepler-62f, a super-Earth in the habitable zone. #astronomy #exoplanets
First Exoplanet with Water Vapor in Habitable Zone By NASA Ames/JPL-Caltech - http://www.nasa.gov/mission_pages/kepler/news/kepler-62-kepler-69.html, Public domain, https://commons.wikimedia.org/w/index.php?curid=25666606
2014 CE
First Exoplanet Discovered by TESS Precursor
The Transiting Exoplanet Survey Satellite (TESS) precursor, the Kilodegree Extremely Little Telescope (KELT), discovers KELT-9b, an ultra-hot Jupiter. #astronomy #exoplanets
First Exoplanet Discovered by TESS Precursor By NASA - NASA/JPL-Caltech, Public domain, https://commons.wikimedia.org/w/index.php?curid=59686404
Jul 23, 2015 CE
Kepler-452b: Earth's Cousin
Kepler-452b is announced as a near-Earth-sized planet in the habitable zone of a Sun-like star, dubbed Earth's cousin. #astronomy #exoplanets
Kepler-452b: Earth's Cousin By NASA Ames/JPL-Caltech/T. Pyle - http://www.nasa.gov/image-feature/soaking-up-the-rays-of-a-sun-like-star-artistic-concept, Public domain, https://commons.wikimedia.org/w/index.php?curid=41807518
Aug 24, 2016 CE
Proxima Centauri b Discovered
A terrestrial planet is discovered orbiting Proxima Centauri, the closest star to the Sun, within its habitable zone. #astronomy #exoplanets
Proxima Centauri b Discovered 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. #astronomy #exoplanets
TRAPPIST-1 System Announced 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 bright stars for exoplanets. #astronomy #exoplanets
TESS Launched 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
Oct 8, 2019 CE
Nobel Prize for Exoplanet Discoverers
Michel Mayor and Didier Queloz win the Nobel Prize in Physics for the discovery of 51 Pegasi b. #astronomy #exoplanets
2020 CE
First Exoplanet with a Magnetic Field Detected
HAT-P-11b shows evidence of a magnetic field via carbon absorption lines. #astronomy #exoplanets
First Exoplanet with a Magnetic Field Detected By PurpuriteRite - Own work, CC0, https://commons.wikimedia.org/w/index.php?curid=146249129
Dec 25, 2021 CE
James Webb Space Telescope Launched
JWST launches, capable of characterizing exoplanet atmospheres in unprecedented detail. #astronomy #exoplanets
James Webb Space Telescope Launched By NASA - https://www.jwst.nasa.gov/content/webbLaunch/whereIsWebb.html, Public domain, https://commons.wikimedia.org/w/index.php?curid=114125719
Aug 25, 2022 CE
JWST Detects CO2 in Exoplanet Atmosphere
JWST detects carbon dioxide in the atmosphere of WASP-39b, demonstrating its capability for biosignature searches. #astronomy #exoplanets
JWST Detects CO2 in Exoplanet Atmosphere 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
Sep 11, 2023 CE
JWST Detects Water Vapor on TRAPPIST-1 Planets
JWST detects water vapor on TRAPPIST-1 planets, advancing the search for habitable worlds. #astronomy #exoplanets
2024 CE
First Exoplanet with Potential Biosignature
JWST detects dimethyl sulfide in the atmosphere of K2-18b, a potential biosignature, though further confirmation needed. #astronomy #exoplanets
First Exoplanet with Potential Biosignature 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
