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Period: 276 BCE to 195 BCE
Eratosthenes
-used the sun to measure the size of the round Earth/ its circumference -he did this in 240 B.C. -he proved that the Earth wasn't flat -
Period: 90 to 168
Claudius Ptolemy
-geocentric theory/ model of the solar system
-cataloged 48 constellations
-he made the model in 150 CE
-formed the basis of our knowledge about the motions of stars and planets for over than a 1000 years -
Period: 1473 to 1543
Nicolaus Copernicus
-discovered the Heliocentric Theory of the universe
-proved the Earth and other planets revolve around the sun
-he did this in by 1510 -
Period: 1546 to
Tycho Brahe
-he achieved his goal of measuring to one minute of arc
-also correctly established the positions of 1,000 fixed stars
-he did this in 1572
-his work helped Kepler make his own discovery and it also helped us know accurate measurements of the positions of stars and planets -
Period: 1571 to
Johannes Kepler
-calculated three laws involving the motions of planets
-he did this in 1609
-supported the heliocentric model, explained how the Sun rises and sets -
Period: to
Sir Isaac Newton
- calculated three laws describing the motion of forces between objects -invented calculus -he did this in 1686 -helped us understand how gravity works, help better solve math problems
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Period: to
Albert Einstein
-found that laws of physics are the same throughout the universe
-found that the speed of light in a vacuum is constant
-found that space and time are linked in an entity known as space-time
-he did this before 1916
-helped us better understand space, time, gravity, and the universe