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Chapter 3

Ancient civilizations did much with science Marked the time of day- St. peter's Square Marked the seasons- Stonehenge Lunar calendars

After observing practical use, explain what was going on wasobservations that they tried to analyze and often us quantitative methodsto understand nature- Pythagoras and Aristotle

Pythagoras- earth centered model in which the earth was round One big problem with the Earth Centered model was it didnt explain

retrograde motion. Ptolemy solved this with the Ptolemaic model. This model was the planets

moving in small epicycles which explain why it looks like it is retrograde attimes. His theory had to keep being tweaked and it was too complicated,but he took a ton of data

Epicycles are small loops that planets make while moving in a larger circle Earth circumference is just of 40,000 km Copernicus- didnt believe in the retrograde motion and thought of a sun

centered theory, but couldn't get away from the idea that the rotationswere perfect circles.

Tycho- saw a supernova and took massive amounts of naked eye data,but couldn't get a final theory.

Kepler- discovered the ellipse, an oval around to foci. Law 1: the orbit of each planet about the sun is an ellipse with the

sun at one focus Law 2: As a planet moves around its orbit it sweeps out equal areas

in equal times. AKA a planet moves faster when it is near the sun andslower when it is closer to the far point.

Law 3: Kepler's third law: More distant planets orbit the Sun atslower average speeds obeying the precise mathematicalrelationship of P^2=a^3 where P is the planets orbital periods inyears and A is the average of the closest it gets to the sun along withthe farthest it gets to the sun.

In each ellipse the closest a planet gets to the sun is Perihelion, thefarthest is Aphelion

Galileo answered 3 questions, how the earth could be moving? How itcould travel in ellipses? And retrograde motion?

1.) Newton's law of motion: remains in motion unless a force acts to stopit.

2.) he disproved circular motion based on non imperfections by noticingcomets and craters on Mars and the Moon

3.) he noticed that milky way was way farther away and consisted of morestars that they though. And he saw moons orbiting Jupiter and Saturn andNOT Earth.

Ocaam's razor- the idea scientists should side with the simpler of the twomodels.

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Telescope invented in 1608 by Hans Lippershey, but Galileo's was muchmore powerful