Astronomy

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Stonehenge

3000 BCE - 1000 BCE

used as a calendar

Eudoxus

409 BCE - 356 BCE

Model of 27 nested spheres

Aristotle

384 BCE - 322 BCE

divided the universe into the perfect heavens and the static earth. Uniform circular motion

Hipparchus

190 BCE - 120 BC

Placed Earth away from the center of the perfect spheres

Ptolemy

90 ad - 158

Added epicycles to account for retrograde motion.

Copernican Revolution

1500

On the Revolution

1543

written by Copernicus. Didn't account for varying speeds of planets or nonperfect circles

Tycho Brahe

1546 - 1601

made very precise observations. disproved the perfect universe. believed everything orbited the sun which orbited the earth.

Galileo Galilei

1564 - 1642

invented observational based science. wrote a dialogue of 2 chief world systems. supported the Copernican model.

Johannes Kepler

1571 - 1630

used brahe's observations. discovered the non-uniform velocities of the elliptical paths of the planets. 1st to accurately predict planetary motions.

Kepler's Laws

1600
  1. Orbits are elliptical with the Sun at one focus
  2. p2=a3
  3. A line from the planet to the Sun sweeps over equal areas in equal intervals of time

Isaac Newton

1642 - 1727
  1. inertia
  2. F=ma
  3. equal and opposite reactions