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Proposed the geocentric theory
The Greek astronomer Ptolemy used measurements of the sky to create his geocentric model. This had the earth at the center and all the planets and the sun orbiting around it. -
1543
Created the heliocentric model of the universe
Nicolaus Copernicus
was a Renaissance mathematician and astronomer who created the heliocentric model of the universe that placed the Sun, instead of the earth, at the center. -
1571
Johannes Kepler
German astronomer who discovered three major laws of planetary motion, conventionally designated -
The first discovery
Galileo discovered the Galilean moons. These satellites were the first celestial objects that were confirmed to orbit an object other than the Sun or Earth. -
Edmond Halley
English astronomer and mathematician who was the first to calculate the orbit of a comet later named after him. -
Solar system
In 1781, William Herschel was looking for binary stars in the constellation of Taurus when he observed what he thought was a new comet.He discovered new planet called Uranus.
The term "Solar System" first appeared in English. -
Discovery of the asteroid
In 1801, while making a star map, Italian priest and astronomer Giuseppe Piazzi accidentally discovered the first and largest asteroid, Ceres, orbiting between Mars and Jupiter. -
Urbain Le Verrier
Urbain Jean Joseph Le Verrier was a French mathematician who specialized in celestial mechanics and is best known for predicting the existence and position of Neptune using only mathematics. So he discovered Neptune -
Clyde William Tombaugh
Clyde William Tombaugh was an American astronomer. He discovered Pluto in 1930, the first object to be discovered in what would later be identified as the Kuiper belt. -
Voyagers 1 and 2
Voyager 1 is a space probe launched by NASA on September 5, 1977. Part of the Voyager program to study the outer Solar System, Voyager 1 launched 16 days after its twin, Voyager 2.