1. THE SOLAR SYSTEM Chapter 24A

2. Unit Objectives Compare models of the solar system To list and describe the objects in our solar system

3. Ideas about the Solar System Early people:  Everything goes around Earth  Geocentric Greeks:  Everything fixed on spheres that go around Earth  Geocentric Nicolaus Copernicus (1473-1543):  The center of Earth is not the center of the universe or of gravity  Motion of the sky is due to Earth’s motion  The sun is the center of the solar system  Heliocentric

4. Ideas about the Solar System Galileo Galilei (1564-1642):  Used telescope (new invention) to look at planets and sun  Phases of Venus, sunspots and moons of Jupiter evidence to support heliocentric solar system Tycho Brahe (1546-1601):  Careful, detailed observations of stars and planets without telescope Rudolphine Tables  Proposed geo-heliocentric model of solar system  Sun and moon orbit Earth, everything else orbits sun Johannes Kepler (1571-1630):  Brahe’s assistant  Used data to formulate laws of planetary motion

5. Kepler’s Laws of Planetary Motion Published in defense of heliocentric views The laws:  The orbit of every planet is an ellipse, with the sun at one of the foci  A line joining the sun and the planet sweeps out equal areas in equal times  In other words  The square of the period of a planet’s orbit is directly proportional to the cube of that planet’s distance from the sun  In other words

6. Modern view of Solar System Made up of planets and other objects that orbit the sun The sun contains 99.86% of the total mass in the solar system  Gravity holds objects in orbits  The Solar System - Astronomy For Kids - KidsAstronomy.com The Solar System - Astronomy For Kids - KidsAstronomy.com