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Period: 240 BCE to 240 BCE
Eratosthenes Calculated The Circumference Of The Earth
Greek mathematician, Eratosthenes, devised a way to calculate the circumference of the Earth with the basic technologies he had available to use.
Eratosthenes calculation of the circumference of the Earth proved earlier theories about the Earth being round and not flat. -
Period: 150 BCE to 150 BCE
Claudius Ptolemy Created The Ptolemaic System (Geocentric System)
Greek astronomer, Claudius, Ptolemy created a system to calculate the position of any known celestial object in the universe, known as the Ptolemaic System (Geocentric System). Ptolemy's model of the universe had Earth at the center with the Sun and the planets known at the time orbiting the Earth.
Ptolemy's system is important because it was believed to be accurate and correct until Copernicus proved that it was flawed. -
Period: 1508 to 1514
Nicolaus Copernicus Created The Heliocentric Theory Of The Universe
Astronomer and mathematician, Nicolaus Copernicus, created The Heliocentric Theory which had the sun in the center of the universe instead of the Earth and the planets known at the time orbiting the Sun, including the Earth.
Copernicus's theory was important because it proved that the long thought to be true theory where Earth was at the center of the universe was wrong and that the Sun is at the center of the universe. -
Period: to
Tycho Brahe Created The Tychonian System (Geo Heliocentric System)
Dutch astronomer, Tycho Brahe, created the geo heliocentric system in 1583 which had the sun and moon orbiting the earth, but the rest of the planets orbiting the Sun. The Tychonic system was important because it combined both Ptolemy's and Copernicus's theories into one new theory. -
Period: to
Johannes Kepler Created The Three Laws Of Motion
German astronomer, Johannes Kepler, created the first two laws of motion in 1609 and the third law of motion in 1618. Kepler's three laws of motion are important because they paved the way for more fundamentally important discoveries about the universe, like gravitational force which majorly affects the way we study and view the universe today. -
Period: to
Isaac Newton Discovers Gravity
English mathematician, Isaac Newton, discovered gravity in 1665 or 1666, when he was sitting under an apple tree and an apple fell on his head. Newton's discovery was important because gravity is the basis of many important theories we use today. -
Period: to
Albert Einstein Created The Theory Of Relativity
German theoretical physicist, Albert Einstein, created the theory of relativity in 1905 which changed the way we view the universe forever. Einstein's theory solidified and proved Isaac Newton's theory on gravity.