Astronomy

Aristotle

384 BCE

384- 322
Along with Ptolemy, Aristotle purposed a model of the solar system where the Earth was the center.

Eratosthenes

276 BCE

276-195 BC
He was the first one to disprove that the Earth was flat by measuring it properly.

Claudius Ptolemy

90

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.

Azophi

903

903-986
First astronomer to make an observation of a group of stars outside of the Milky Way Galaxy.

Nicolaus Copernicus

1473

1473- 1543
First astronomer to purpose a model of the solar system where the Earth revolved around the sun. This model replaced Ptolemy.

Tycho Brahe

1546

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.

Galileo Galilei

1564

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.

Kepler

1571

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.

Isaac Newton

1643

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.

Doppler

1803

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

Albert Einstein

1879

1879-1955
Einstein purposed a new way of looking at the universe. He suggested that the laws of physics were constant throughout the universe.

Edwin Hubble

1899

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.

Frank Drake

1930

1930-
Purposed the Drake equation which is used to calculate the number of extraterrestrials in the Milky Way Galaxy.

Stephen Hawking

1942

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.