1891Throop University - the precursor to Caltech - established


1902Carnegie Institution of Washington established
1904George Ellery Hale becomes the first Director of Mt. Wilson Observatory
Mt. Wilson Solar Observatory funded by the Carnegie Institution of Washington
1905Snow Solar Telescope on Mt. Wilson takes its first solar spectrum
1908Mt. Wilson 60 foot Solar Tower built
Mt. Wilson 60 inch Telescope completed; the largest telescope in the world at the time
George Ellery Hale discovers magnetic fields in sunspots


1912150 foot Solar Tower completed at Mt. Wilson
1917100 inch Hooker Telescope completed at Mt. Wilson; the largest telescope in the world from 1917-1949
1919Stellar interferometer added to 100 inch telescope
Harlow Shapley discovered shape of our Milky Way galaxy


1920 Throop College of Technology is renamed the California Institute of Technology
Harlow Shapley-Heber Curtis "Great Debate" on the size of the universe
1921First measurement of the size of another star: Betelgeuse
1923Robert A. Millikan - Chairman of Caltech Executive Council (1921-1945) - wins the Nobel Prize for Physics
Edwin Hubble discovers Andromeda, M31, is a galaxy
1924 Edwin Hubble shows many other galaxies exist beyond our own Milky Way
Pasadena Junior College - now known as Pasadena City College (PCC) - is established on the Pasadena High School Campus
Edwin Hubble shows many other galaxies exist beyond our own Milky Way
1928Grant from the Rockefeller Foundation for the fabrication of a 200 inch reflecting telescope
1929Edwin Hubble discovers the universe is expanding and measures the size of the known universe


1931 Einstein visit to Caltech; Einstein was a visiting professor at Caltech during the winter terms of 1931-33
Opening of the new observatory building at Pasadena City College (PCC) - dedicated by Albert Einstein
1933Caltech Astronomer Fritz Zwicky finds the first evidence for ‘dark matter’ at Mt. Wilson
1936 18 inch Schmidt telescope installed at Palomar Mountain
Student rocket experiments conducted at Arroyo Seco; these early experiments ultimately led to the establishment of JPL


1944Walter Baade at Mt. Wilson Observatory first recognizes different populations of stars
Jet Propulsion Laboratory officially named
1948The Palomar 200 inch (5.1 meter) telescope dedicated - largest telescope in the world until 1976
48 inch (1.2 meter) wide-field Schmidt telescope takes its first official photograph


1952By identifying two classes of "Cepheid variable" stars, astronomer Walter Baade refines the extragalactic distance scale - the estimated size of the known universe doubles
1958Allan Sandage, working at Palomar Observatory, publishes first accurate estimate of the rate of expansion of the universe, and updates the "Hubble constant"
Launch of Explorer 1, first US satellite and first-ever orbital science experiment
JPL transferred from Army to NASA
Caltech's Owens Valley Radio Observatory (OVRO) becomes operational


1960Beginning of the Mariner program to explore the planets. 10 missions launched through the early 1970s
Helioseismology studies of the Sun begin at the Mt. Wilson 60 foot Tower telescope
1962Mariner 2 flyby of Venus
1963Caltech astronomer Maarten Schmidt discovers a new type of object - quasars - using the Palomar 200 inch telescope
1964Ranger 7 is the first US mission to the Moon
1965Planetarium is completed at PCC
1966Surveyor 1 is the first US lander on the Moon
1969Establishment of Las Campanas Observatory (LCO) in Chile by Carnegie Observatories


1970Caltech's 60 inch telescope completed and begins observations at Palomar Observatory
1971Carnegie Observatories begins operations with the Henrietta Swope telescope - 1 meter (40 inch) reflector - at Cerro Las Campanas in Chile
1973Over 120 supernovae discovered using the Palomar Schmidt telescopes by Caltech astronomer Fritz Zwicky
Palomar Planet-Crossing Asteroid Survey initiated by Eleanor Helin
1975Launch of Viking 1 mission to Mars
Viking 2 launch
1976Viking 1 lands on Mars
Viking 2 lands on Mars
1977Carnegies Observatories begins operations of the Irénée du Pont 2.5 meter (100 inch) telescope at Las Campanas, Chile
Voyager 1 & 2 launched
1979Kidspace Children's Museum founded at the California Institute of Technology


1980Voyager 1 at Saturn
Kidspace opens in the Rosemont Pavilion on Arroyo Seco. JPL collaborates for exhibit design and construction
The Planetary Report magazine established
1981Discovery of giant voids and the cosmic web by Carnegie astronomers Steve Shectman, Alan Dressler and others
Kidspace relocates to McKinley School
1984Laser Interferometer Gravitational-Wave Observatory (LIGO) founded as a Caltech/MIT project
1985IPAC is established at Caltech, initially to support the Infrared Astronomical Satellite (IRAS) extended mission
Beginning of construction of the Keck I 10 meter telescope on Maunakea, Hawaii
1986Non-profit Mount Wilson Institute assumes management of mountain
1987Discovery of Supernova 1987A (SN 1987A) at Las Campanas Observatory by Ian Shelton and Oscar Duhalde
Caltech Submillimeter Observatory (CSO) has first light on Maunakea, Hawaii with an image of M82
1989Voyager 2 at Neptune
Galileo mission to Jupiter launched


1990NASA/IPAC Extragalactic Database (NED) founded
Keck I telescope on Maunakea begins operation
1991Galileo spacecraft flies by asteroids Gaspra and Ida
1992Mt. Wilson 60 inch telescope outfitted with adaptive optics
Mt. Wilson 100 inch Hooker Telescope reopened
1993Infrared Science Archive (IRSA) established at IPAC
WFPC2 camera, built by JPL, installed on the Hubble Space Telescope
1994LIGO site construction begins at Hanford, Washington
1995LIGO site construction begins at Livingston, Louisiana
IPAC begins US support of ESA's Infrared Observatory in Space (ISO)
Mt. Wilson 100 inch Hooker Telescope outfitted with adaptive optics
Galileo spacecraft begins orbiting Jupiter
1996Keck II telescope begins operations on Maunakea
Mars Pathfinder launched
1997IPAC begins analysis, processing and archiving for 2MASS, first high-resolution all-digital sky survey
IPAC is assigned the Spitzer Science Center in support of NASA's Spitzer Space Telescope
100 inch Hooker Telescope added laser guide star system
Pathfinder lands on Mars
Cassini - a mission to Saturn - launched
1998Deep Space 1, a test for ion propulsion, launched
1999First detection of a transiting exoplanet around another star (HD 209458)
Stardust - a comet sample return mission - launched


2000Shuttle Radar Topography Mission maps Earth from the Space Shuttle Endeavour
First light for the Walter Baade telescope - the first of the twin 6.5 meter Magellan telescopes
2001Mars Odyssey launched
Genesis - a mission to return a sample of the solar wind - launched
Deep Space 1 arrives at comet Borrelly
2002Kidspace begins renovation of the Fannie Morrison Horticultural Center buildings in Brookside Park
Landon Clay telescope - the second of the twin 6.5 meter Magellan telescopes - begins science operations
First episode of Planetary Radio, a weekly space science radio show/podcast from The Planetary Society
2003Galaxy Evolution Explorer (GALEX) mission launched
Carnegie astronomers determine that supermassive black holes are found in nuclei of all galaxies
Mars Exploration Rovers - Spirit and Opportunity - launched
Foundation of the nonprofit Thirty Meter Telescope (TMT) Observatory Corporation
NASA's Spitzer Space Telescope - Hubble's infrared-light sibling - launched
2004Spirit & Opportunity land on Mars
Kidspace Children's Museum is reopened at its current location in Brookside Park
Center for High Angular Resolution Astronomy (CHARA) interferometer completed on Mt. Wilson
Stardust arrives at comet Wild 2
First GMT primary mirror is cast at Steward Observatory Mirror Lab (now Richard F. Caris Mirror Lab)
Genesis returns solar wind sample to Earth, the first material collected and returned from beyond the Moon
2005Caltech astronomers using Keck determine the Andromeda galaxy is 3x larger than previously thought
Acceleration of the expansion of the Universe
Cosmos Award for Public Presentation of Science established by The Planetary Society
Caltech astronomer Mike Brown discovers Eris, an object more distant and massive than Pluto
Deep Impact launched
Huygens lands on Titan
Spitzer Space Telescope detects the first light ever seen from planets orbiting other stars
TMT begins formal design process
Spitzer Space Telescope makes first weather map of an exoplanet
Cosmos 1, The Planetary Society's first solar sail spacecraft, launched but fails to reach orbit
Deep Impact probe collides with comet Tempel 1
Deep Impact & Spitzer announce 'ingredients' of Tempel 1
2006GMT Conceptual Design Review held
Stardust returns first sample of a comet to Earth
Discovery of Eris prompts astronomers to demote Pluto to "Dwarf Planet" status
2007Palomar Transient Factory (PTF) automated survey begins
Dawn mission to Vesta and Ceres launched
2008GMT partners sign Founders Agreement and form GMTO Corporation
2009US Planck Science Data Center at IPAC co-releases its first maps of the cosmic microwave background
Kidspace celebrates its millionth visitor
The Planetary Society announces LightSail project, a plan to sail a spacecraft on sunlight alone
The Planetary Society develops Living Interplanetary Flight Experiment (LIFE)
Astronomers using Keck telescope detect methane on Mars
Kepler planet-finding mission launched
TMT completes a 5 year Design Development Phase
Palomar Transient Factory (PTF) detects its first supernova (of thousands to come)
Launch of Herschel Space Observatory
Spitzer Warm Mission begins
Mauna Kea selected as preferred site for TMT
Spitzer discovers Saturn's largest ring
Wide-Field Infrared Survey Explorer (WISE) launched
Wide-Field Infrared Survey Explorer (WISE) satellite data processing & archiving begins at IPAC


2010Successful Final Design/Construction Readiness Review of TMT
Large Binocular Telescope Interferometer (LBTI) commissioned to study exoplanetary systems
2011Launch of STS-134 Shuttle LIFE experiment
Dawn spacecraft arrives at Vesta
Herschel Space Observatory discovers oxygen molecules in space
Mars Curiosity rover launched
Kepler finds 4500 candidate exoplanets; over 1000 confirmed
2012GMT site leveled and infrastructure development begun
First GMT mirror completed
Second GMT primary mirror cast
Launch of the first focusing hard x-ray telescope - NASA's Nuclear Spectroscopic Telescope Array (NuSTAR) mission
Voyager 1 reaches interstellar space
Kidspace collaborates with Caltech to open the new Galvin Physics Forest
Curiosity lands on Mars
2013 NuSTAR helps solve riddle of spinning black holes
U.S. National Science Foundation awarded a partnership-planning grant to TMT
Signature of TMT Master Agreement amongst the international partners
Third GMT primary mirror cast
2014 Large Synoptic Survey Telescope (LSST) Science User Interface and Tools Center assigned to IPAC
Eyepiece viewing commissioned at 100 inch Hooker Telescope, dedicated to public use
TMT segment support assembly prototype completed
GMT passes System Level PDR and Cost Review
NuSTAR maps radioactivity in supernova remnant for first time
Kidspace welcomes its 4 millionth visitor
Formation of TMT International Observatory LLC (TIO)
2015 Dawn spacecraft arrives at the dwarf planet Ceres
Spitzer determines distance to one of the most distant exoplanets known
Launch of Lightsail 1 - a solar sail spacecraft from The Planetary Society
LightSail 1 deploys solar sail
GMT Board announces start of construction
Spitzer finds 'Buckyball' molecules in space around dead stars
Fourth (center) GMT mirror cast
GMT groundbreaking ceremony at Cerro Las Campanas, Chile
Hawaii Supreme Court revokes TMT construction permit
2016 LIGO announces the first discovery of strong gravitational waves from a collision of two black holes
TMT initiates detailed studies of alternate sites for the telescope
Spacecraft Juno enters orbit at Jupiter
Final design and production readiness phases of the TMT enclosure
Kidspace debuts a new mobile Discovery Dome for outreach and education
Cosmos Award for Public Presentation of Science presented at Division of Planetary Sciences (DPS) meeting in Pasadena by Bill Nye from The Planetary Society
GMT site infrastructure development complete
2017 The Planetary Society planned launch of LightSail 2 - a solar sail spacecraft
2018 James Webb Space Telescope launch; commissioning and first images from "Mid-Infrared Instrument" (MIRI)
Start of TMT observatory construction (estimated)
JPL's "Interior Exploration using Seismic Investigations, Geodesy and Heat Transport" (InSight) mission lands on Mars


2022GMT first light (estimated)
2024GMT fully commissioned (estimated)
2025Wide Field InfraRed Survey Telescope (WFIRST) launch (estimated for mid-2020's)
Asteroid Redirect Robotic Mission (ARRM) - first robotic mission to collect boulder from asteroid - launch (estimated for mid-2020's)
2028TMT first light (estimated)