Astronomy Exam 1

Front 1

Eratosthenes

Back 1

1) he knew during summer solstice that the sun was as far north as it travels, casting no shadows at noon at Syene. He from there used sundials and determined from where he was in Alexandria it was about 7.2 degrees south of zenith 2) the sun is very far away Circumstance- 50 times distance from Alexandria to meters 250,000 stadion ~ 46,250 kilometers

Front 2

Aristarchas of Samos

Back 2

The size of the Moon relative to the size of the Earth's shadow during a total lunar eclipse.earth is 3 times bigger than moon Sun is 19 times bigger than moonSun is 57 times bigger than earth Moon is 70 earth radius away sun 19 times further away than moon, making sun 1,330 earth radio in distance

Front 3

Thales of Miletus

Back 3

first recorded to us who began to seek to explain nature without mythology (came into conflict with society)work didn't survive but know of him because of his student AnaximanderPredicted Eclipses & applied geometry to astronomy and surveying.

Front 4

Anaximander

Back 4

Flat, cylindrical Earth fixed at the center of the universeCelestial bodies move on circles & lie at different distances from Earth. Considered celestial bodies physical objects governed by knowable physical laws

Front 5

Pythagoras

Back 5

spherical earth fixed at centerSize of spheres were ratios of small numbers (2:1, 3:2)ideals of perfectionVibrations from their rubbing together created a harmonious “Music of Spheres”

Front 6

Eudoxus

Back 6

proposed a system of 27 nested crystalline spheres as a way of describing planetary motion pupil of pluto- incorporated platonic motion combined motions of the nested spheres reproduced the motions of the heavens.

Front 7

Aristotle

Back 7

Earth is fixed & unmoving at centerAll spheres in uniform circular motion55 crystalline spheres eudoxus 27 crystalline was not sufficient to explain tremendous complexity of motion of planetsin constant speed along a circular pathearth is too big to rotate and move

Front 8

Aristarchus of Samos

Back 8

Heliocentric (Sun−centered) system Aristarchus set the sun, the biggest thing he knew of in heavens , fixed and unmoving at center of the universe figured if aristotle thought the earth was too big to move and be in motion, a moving sun which was way bigger was a big inconsistency Aristarchus theory was widely dismissed

Front 9

Hipparchus of Nicaea

Back 9

earth located at an off-center eccentric to reproduce variations in the apparent angular speed of the objectpreserved idea of uniform circular motionmade more accurate predictionsEliminated Crystalline Spheres

Front 10

Claudius Ptolmy

Back 10

Uniform angular motion about an off-center equant. More Complicated, but makes better predictions. introduced equant to better predict speeds of the retrograde motions EX) slow, fast, bigger, and smaller loops