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240 BCE
Eratosthenes makes the first accurate measurement of the circumference of the Earth.
Eratosthenes was born in 276 BC in Cyrene, ancient Greece (in what is now Libya) and died in 195 BC. He was known for making the first accurate measurement of the circumference of the Earth in 240 BC. -
190 BCE
Hipparchus discovers the precession of the equinoxes
Hipparchus was an astronomer and a mathematician who was born in 190 BC in what is now present day Turkey. He is most famous for discovering the equinoxes. He died in 120 BC (exact time he discovered the equinoxes isn't known). -
140
Ptolemy proposes the geocentric theory
Claudius Ptolemy was born in 90 AD in Alexandria, Egypt. He died in 168 AD. He was most famous for his geocentric theory and believed that the Earth was the center of the center of the universe (which was later proven to be false). -
Jan 1, 1514
Nicolaus Copernicus proposes the Heliocentric Theory.
Nicolaus Copernicus was born February 19, 1473 in Poland. He died May 24, 1543. He was most famous for writing Commentariolus, a 40-page manuscript summarizing the heliocentric planetary system and proof. (exact date is unknown, he wrote it around 1514) -
Nov 11, 1572
Tycho Brahe sees a supernova and decides to devote the rest of his life to astronomy
Tycho Brahe was born in Denmark on December 14, 1546. He died on October 24, 1601. He believed in a geocentric universe (where the Earth is in the center) and was famous for discovering "Tycho's Supernova." -
Johannes Kepler replaces Tycho Brahe and formulates "Kepler's Laws"
Johannes Kepler was born in Germany on December 27, 1571. He died on November 15, 1630. He was most famous for calculating the motion and orbits of our planets, which became Kepler's laws of planetary motion. -
Galileo discovers Jupiter's 4 largest moons (Galilean Moons)
Galileo Galilei was born on February 15, 1564 in Italy. He died on January 8, 1642. He was most famous for using a telescope to discover Jupiter's 4 largest moons: Io, Ganymede, Europa, and Callisto. -
Giovanni Cassini-Saturns ring gap
Giovanni was born in Italy on June 8th 1625. He was most famous for discovering the gap between Saturn's rings now known as Giovanni gap. He died on September 14th 1712. -
Newton publishes the Principia
Sir Isaac Newton was born in the UK on January 4, 1643, and died March 31, 1727. He was most famous for the laws of gravitation and motion, which was one of the topics covered in his book, the Principia. -
Edmund Halley - Halleys Comet
Edmund Halley was born in 1656 on November 8th. He was born in Haggerston, London . He was most famous for finding the orbit of a comet now known as Halley's Comet. He died January 14, 1742. -
Willam Herschel -Founded Uranus and its two moons.
William Herschel was born November 15th 1738. He was born in Hanover, Germany. He was most famous for Discovering Uranus and its two moons as well as formulating the theory of stellar evolution. He died August 25, 1822. -
Charles Messier: "Messier Objects"
Charles Messier was born in France 1730 on June 26th. He was most famous for his 110 clusters found that are now called "Messier Objects" They consist of nebulae and star clusters. He died in 1817 on April 12th. -
Johann G. Galle discovers planet Neptune
Johann G. Galle was born on June 9, 1812 in Radis, Germany. He is most famous for discovering the planet Neptune. He died on July 10, 1910. -
Edwin Hubble proves that other galaxies are moving away from each other at a constant rate
Edwin Hubble was born on November 20, 1889 in Marshville, Missouri. He died on September 28, 1953. He was most famous for identifying the relationship between a galaxy's distance and the speed with which it is moving in 1929. -
Stephen Hawking
Stephen Hawking was born in the UK on January 8, 1942. He is still alive today and is 74 years old. He is most famous for his theories black holes, one being that all space and time begins with a Big Bang and ends with a black hole. -
Carl Sagan- Most famous for papers, books and TVseries
Carl Sagan was born on November 9th 1934 in Brooklyn NY. He was most famous for his papers and books on astronomy and natural sciences. He was also famous for a 1980's TV show called " Cosmos: A Personal Voyage". He died on December 20, 1996. -
Works Cited
www.livescience.com
www.space.com
kepler.nasa.gov
www.britannica.com
www.physicsoftheuniverse.com
www.famousscientists.org
famousastronomers.org
www.windows2universe.org
