-
350 BCE
Aristole describes the geocentric model of the universe
-
200 BCE
Aristarchus proposes a heliocentric model of the universe that is widely ignored
-
150 BCE
Ptolemy refines the geocentric model of the universe to try to explain the retrograde motion of the planets
-
1520
Ferdinand Mageilan is the first European to observe the Magellanic Clouds, which are later recognised as galazies outside the Milky way
-
1543
Nicholas Copernicus publishes a paper that presens the heliocentric model of the universe with a number of improvements on Aristarchus version
-
Giordano Bruno is burnt at the stake. One of his crimes was promoting the heliocentric model of the universe
-
kepler publishes Astronomia Nova, explaining the motion of the planets by using a heliocenntrc model of the universe and elliptical orbits
-
Galileo Galilei observes the moons of Jupiter
-
Galileo publishes his Dialouge on Two world systems, which argues in favour of the heliocentric model of the universe
-
Isaac Newton publishes Princupia Mathematica in which, among other things, he explains thE LAW OF UNIVERSAL GRAVITATION
-
THOMAS WRIGHT SUGGESTS THAT THE milky way galaxy is a flattened disk of stars and that nebulae might be other galaxies
-
Wiliiam Herschel discovers Uranus, the first planet not visible to the naked eye to be discovered
-
William Herschel constructs the first map of the milky way galaxy
-
Friedrich Bassel observes stellar parallax- the apparent movement of starsdue to Earth's movement around the Sun.
-
John Couch Adams discovers Neptune.
-
Ernst Opik demonstrates that the Andromeda nebula lies outside the Milky Way galaxy.
-
Georges Lemaitre proposes the Big Bang theory, which suggests that the universe began as a giant explosion of energy.
-
Edwin Hubble discovers evidence of an expanding universe, which supports the Big Bang model.
-
Clyde Tombaugh discovers Pluto.
-
Arno Penzias and Robert Wilson discover cosmic microwave background radiation, further evidence supporting the Big Bang model.
-
Neil Armstrong and Buzz Aldrin are the first human beings to walk on the surface of the Moon.
-
Pioneer 10 becomes the first spacecraft to leave the solar system. The spacecraft Galileo returns data suggesting that Europa has liquid oceans under its icy surface.
-
The spacecraft Galileo returns data suggesting that Europa has liquid oceans under its icy surface.
-
Planet-sized objects Eris, Haumea and Makemake are discovered in the Kuiper Belt
-
The international Astronomical Union rules that Pluto is not a planet