History of Astronomy
From naked-eye observers to space telescopes: the discoveries that changed how we see the sky.
- c. 150 CE
Ptolemy’s Almagest
Ptolemy describes a model with Earth at the centre. It guided astronomers in Europe and the Islamic world for well over a thousand years.
- 1543
Copernicus puts the Sun at the centre
Nicolaus Copernicus publishes On the Revolutions of the Heavenly Spheres, proposing that Earth and the other planets orbit the Sun.
- 1609-1610
Galileo points a telescope at the sky
Galileo observes the Moon’s craters, Jupiter’s four largest moons and the phases of Venus, evidence against an Earth-centred sky.
- 1687
Newton explains gravity
Isaac Newton publishes the Principia, showing that one law of gravity explains falling objects and planetary orbits.
- 1781
A new planet
William Herschel discovers Uranus, the first planet found with a telescope.
- 1838
The first distance to a star
Friedrich Bessel measures the parallax of the star 61 Cygni, proving stars are very far away.
- 1840
The first photo of the Moon
John William Draper takes a daguerreotype of the Moon, the start of astrophotography.
- 1846
Neptune found by mathematics
Urbain Le Verrier predicts where an unseen planet must be, and Johann Galle finds Neptune where he said.
- 1929
The universe is expanding
Edwin Hubble shows that distant galaxies are moving away from us, with farther ones receding faster.
- 1930
Pluto discovered
Clyde Tombaugh finds Pluto. It was reclassified as a dwarf planet in 2006.
- 1957-1969
The space age
Sputnik 1 (1957), Yuri Gagarin in orbit (1961) and Apollo 11’s Moon landing (1969).
- 1977
Voyager launches
Voyager 1 and 2 begin tours of the outer planets. Voyager 1 later becomes the most distant human-made object.
- 1990
Hubble Space Telescope
Launched in 1990, Hubble gives sharp views of the universe from above the atmosphere.
- 1995
The first exoplanet around a Sun-like star
Michel Mayor and Didier Queloz announce 51 Pegasi b.
- 2015-2016
Gravitational waves
LIGO detects ripples in space-time from two merging black holes, announced in February 2016.
- 2019
The first photo of a black hole
The Event Horizon Telescope releases its image of the supermassive black hole M87*. An image of Sagittarius A* followed in 2022.
- 2021-2022
James Webb Space Telescope
Launched on December 25, 2021, JWST released its first full-colour images in July 2022.
- 2026
Artemis II
Artemis II sends astronauts around the Moon, the first crewed lunar flyby since the Apollo era.