History of Solar System

Ptolemy

150

Started the Geocentric idea of the universe. The idea of geocentric actually started years before, but Ptolemy explained it in detail. The model is extremely confusing, because it takes all the movements of the celestial body in the solar system into account, as observed on earth. (e.g. the time when earth passes mars, mars seems to move backwards)

Copernicus

Jan 1, 1543

published the heliocentric model. Copernicus's heliocentric model has been challenged and dismissed for many times. However, after centuries, it is clear that he is correct.

Kepler

Dec 27, 1571

He discovered the 3 main laws of planetary motion. Which are: 1) every planet’s orbit is an ellipse with the Sun at a focus; 2) a line joining the Sun and a planet sweeps out equal areas in equal times; and 3) the square of a planet’s orbital period is proportional to the cube of the semi-major axis of its orbit.

Galileo Galilei

Jan 1, 1610

Discovered the 4 moons of Jupiter, and proved that heliocentric is wrong. Galileo Galilei was eventually grounded, because the Pope can't believe that it is true, and it betrays the rules of the bible. (as understand by the Pope)

Edmund Halley

Jan 1, 1705

discovered the pattern of a comet (Halley Comet), and predicted its next appearance which is in 1758. Sadly, Halley died and can't see that he was right.

William Herschel

Mar 13, 1781

Discovered Uranus. He discovered Uranus while searching for a double star. He decided to name it George, after king George.

Discovery of the first 4 asteroids.

Jan 1, 1801

the first 4 asteroids are Ceres, Pallas, Juno and Vesta.

Urbain Le Verrier

Sep 23, 1846

Discovered Neptune using only math. It is so accurate that it is only 1º off.

Clyde Tombaugh

Feb 18, 1930

Discovered Pluto. Pluto is later downgraded to dwarf planet in 2006.