-
384- 322
Along with Ptolemy, Aristotle purposed a model of the solar system where the Earth was the center. -
276-195 BC
He was the first one to disprove that the Earth was flat by measuring it properly. -
90-168
First astronomer to purpose a model of the solar system. His model had the sun and other planets rotating around Earth. Even though his model was wrong, his model is still considered very influential. -
903-986
First astronomer to make an observation of a group of stars outside of the Milky Way Galaxy. -
1473- 1543
First astronomer to purpose a model of the solar system where the Earth revolved around the sun. This model replaced Ptolemy. -
1546- 1601
First astronomer to make accurate measurements and observations of the planets other that Earth. This information was used by most astronomers as an index. -
1564- 1642
Galileo is credited for the first optical telescope. With his telescope he discovered four moons of Jupiter, and Saturn's rings. He also was a big supporter of Copernicus' theory. -
1571- 1630
Purposed the 3 laws of planetary motion
1. All planets move about the Sun in elliptical orbits, having the Sun as one of the foci.
2. A radius vector joining any planet to the Sun sweeps out equal areas in equal lengths of time.
3. The squares of the sidereal periods (of revolution) of the planets are directly proportional to the cubes of their mean distances from the Sun. -
1643- 1727
First scientist to discover gravity. This discovery and his 3 laws are used by astronomers world wide both today and in the past. -
1803-1853
Purposed the Doppler effect which is used to determine how fast a star or other object is moving towards or away from Earth -
1879-1955
Einstein purposed a new way of looking at the universe. He suggested that the laws of physics were constant throughout the universe. -
1899-1953
Purposed Hubble's Law, which stated that the universe was actively expanding and that there is more than one galaxy other than the Milky Way. -
1930-
Purposed the Drake equation which is used to calculate the number of extraterrestrials in the Milky Way Galaxy. -
1942-2018
He purposed that as the universe has a beginning, it most likely has an end. He also says that the universe has no boundary of border.
