science - Timeline

Aristotle describes the geocentric model of the universe

Aristarchus proposes a heliocentric (Sun centred) model of the universe that is widely ignored.

Ptolemy refines the geocentric model of the universe to try to explain the retrograde (east to west) motion of the planets.

Ferdinand Magellan is the first European to observe the Magellanic clouds, which are later recognised as galaxies outside the Milky Way

Nicholas Copernicus publishes a paper that presents the heliocentric model with a number of improvements on Aristarchus' version.

Giordano Bruno is burnt at the stake for promoting a heliocentric model of the universe.

Kepler publishes Astronomia Nova, explaining planetary motion using a heliocentric model of the universe and 2 elliptical orbits.

Galileo Galilei observes the moons of Jupiter.

Galileo publishes his Dialogue of Two World Systems which argues in favour of the heliocentric universe model.

Isaac Newton publishes Principia Mathematica which explains the law of gravity.

Thomas Wright suggests the Milky Way is a flattened disc of stars.

William Herschel discovers Uranus.

Herschel constructs a map of the Milky Way

John Couch Adams discovers Neptune.

Friedrich Bassel observes a star parallax - movement of stars apparent to Earth's position.

Ernst Opik shows the Andromeda galaxy is outside the Milky Way

George Lemaitre proposes the Big Bang theory

Edwin Hubble discovers an expanding universe.

Clyde Tombaugh discovers Pluto

Arno Penzias and Robert Wilson discover cosmic microwave radiation

Neil Armstrong and Buzz Aldrin are the first people to walk on the Moon.

Pioneer 10 leaves the solar system.

The spacecraft Galileo finds ice on Europa.

Planet-sized objects are discovered in the Kuiper Belt.

The Astronomical Union decide Pluto is not a planet.

Astronomers saw the first glimpse of a black hole.

Astronomers find gravitational waves for the first time in history.