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Period: 276 BCE to 194 BCE
Eratosthenes
When most people believe the world was flat, Eratosthenes used the Sun to measure the size of the round Earth. His measurement was only 211 miles off the true measurement. -
Period: 90 to 168
Claudius Ptolemy
Claudius Ptolemy was a famous astronomer and mathematician. Ptolemy created a theory that the Earth was the center of the universe, this was called the Geocentric Theory or the Ptolemaic System. Even though this theory is now proven to be flase, it was believedfor many centuries. -
Period: 1473 to 1543
Nicolaus Copernicus
Nicolaus Copernicus came up with a theory that the Sun was the center of our Solar System. He was not the first to have this theory, but he was the first to use his own observations of the movements of the planets to back it up. This was too different for most scholars of his time to accept, so they only used parts of his theory. -
Period: 1546 to
Tycho Brahe
Tycho Brahe was a Danish astronomer. He inherited many tremendous resources, one of which was enough money to build an observatory. Tycho built vast instruments to set accurate sights on the stars. He achieved his goal of measuring one minute of arc. This was a tremendous feat before the discovery of telescopes. -
Period: 1571 to
Johannes Kepler
Johannes Kepler determined the three laws of planetary motion. These are the laws that Newton used to establish universal gravitation.Kepler was the first to state clearly that the way to understand the motion of the planets was in terms of some kind of force from the sun. Kepler thought that a continuous force was necessary to maintain motion. -
Period: to
Sir Isaac Newton
Sir Isaac Newton was an English astronomer who is most famous for his work on forces, specifically the force of gravity.Sir Isaac Newton calculated three laws describing the motion of forces between objects, now known as Newton's Laws. -
Period: to
Albert Einstein
Albert Einstein became one of the most famous scientists ever after proposing a new way of looking at the universe that went beyond the current understanding. Einstein suggested that the laws of physics were the same throughout the universe, that the speed of light in a vacuum is constant, and that space and time are linked called space-time.