Developing a Model of the Solar System

THE HISTORY OF ASTRONOMY

About 1600 B.C.Recorded position of planetsTimes of eclipses

Early Chinese, Central American, and North European cultures show evidence of studying astronomy

BABYLONIANS

ThalesUsed Babylonian data to predict eclipses

EratosthenesMeasured the circumference of the Earth

HipparchusProduced first star catalog and recorded the names of constellations

ANCIENT GREEKS

Heraclides 330 B.C. Developed the first solar system model with the Earth at the

centerAristarchus

270 B.C. Developed a heliocentric model of the solar system

GEOCENTRIC VERSUS HELIOCENTRIC

200 A.D.Librarian of AlexandriaBelieved Heraclides’ geocentric model of the solar system to

be correctHis model seemed to adequately explain the motion of the

planets, but it was complicated.

PTOLEMY

1500’sBelieved in the heliocentric model

of the solar systemThe Heliocentric model was not

popular with the church

COPERNICUS

1580’SBuilt the Danish ObservatoryMeasured positions of planets and starsShowed that the sun was much farther from the Earth than

the moon is

TYCHO BRAHE

1600’sBrahe’s student

Used Brahe’s data to formulate Laws of Planetary Motion Used elliptical orbits instead of circular orbits

KEPLER

1620’s Developed laws of motion

Natural versus forced Rest versus uniform motion

Used a telescope to discover Spots on the sun Mountains and “seas” on the moon Multiple stars in the Milky Way Phases of Venus Jupiter’s moons

GALILEO

1680’sDeveloped the law of universal gravitationDeveloped the first reflecting telescope

NEWTON