According to Aristotle, all bright lights are made up of aether.
Aristotle believed that the earth is the center of the solar system and the sun and the moon are rotating around the earth.
The Earth was, however, made of water, fire, air, etc.
Aristarchus measured the sizes of the sun and the moon and their distance from the Earth in terms of the Earth's radius.
Aristarchus derived that the Sun was actually six to seven times larger than the Earth.
Aristarchus said that the Earth rotates around the Sun.
Claudius Ptolemy supported the idea of Aristotle on geocentric world.
Ptolemy mathematically reproduced the part were made of aether and they moved in a perfectly circular orbit around the Earth which was made of air, fire, water, earth.
Copernicus proposed that the Sun was the center of motion of the planets and the Earth was the center of motion of the Moon.
Giordano Bruno - An Italian thinker who only supported the Copernican concept of heliocentric world.
Tycho Brahe - is a Danish astronomer who proposed a scenario which was sort of a compromise between Aristotle's world and Copernicus' world.
Tycho Brahe stated that all the planets---Mercury, Venus, Mars, Jupiter and Saturn---move around the Sun forming one system and the Moon and the Sun along with this system move around the Earth.
Tycho Brahe discovered a comet and realized that not all heavenly bodies moved in perfectly circular orbits.
Johannes Kepler is a German mathematician who used the observational records of Tycho Brahe and the Italian physicist Galileo Galilei.
In order to acquire Tycho observational records, Johannes Kepler joined Tycho as his assistant.
Galileo Galilei invented a telescope that made any object larger by 20 times.
Galileo Galilei immediately realized that the Moon was like the Earth and not made by aether as thought by Aristotle.
Christian Huygens - discovered a moon of Saturn called Titan in 1655
Christian Huygens reported the presence of the ring around the Saturn
Jean-Dominique Cassini - an astronomer at the Observatory of Paris, who discovered four more moons orbiting around the Saturn.