Ch. 29 The Solar System

29.1 Models of the Solar System Geocentric model: Earth centered model developed by Aristotle Did not fit observations such as retrograde motion, the backward motion as some planets appear to reverse direction…..

Epicycle model: Planets revolved around earth, but then planets moved in small chain like circles This model considered the observations and attempted to account for them!!!

Heliocentric Model Developed by Copernicus Sun centered model of the Solar System Planets orbit in the same direction Each planet moves at a different speed and distance from the sun

Kepler’s Laws: Ellipses

Kepler’s Laws: Ellipses

Kepler’s Laws: Ellipses

Kepler’s Laws First Law (Law of Ellipses): The orbits of planets are ellipses with the sun at one focus

Kepler’s Laws Second Law (Law of Equal Area): Planetary motion will cover the same area in a given unit of time.

Third Law (Law of Periods): r3 ~ p2 The distance of a planet from the sun cubed (r3) is proportional to the square of the period (p2). Period is defined as the length of time for one revolution around the sun.

Kepler’s 3rd Law Notes

29.2 The Inner Planets Four Planets closest to the sun. Terrestrial Planets : rock like planets, similar to Earth During the formation of the solar system, materials with low boiling points where driven off.

Mercury Planet closest to the sun Period: 88 days Length of a day: 59 Earth Days!!!! Minimal Atmosphere, and slow rotation = HUGE temperature changes between night and day, 427C and -173  C

Venus Period: 225 days Rotation: 243 days Same size, mass, and density as Earth! Dense Atmosphere (96% CO2) Average surface temperature is 464C

Earth Third Planet from the Sun Period: 365.24 days Rotation: 23 hours, 56 minutes Geological Activity Because of the lower amounts of CO2, heat is able to escape. Average temperature: 14C

Mars Fourth planet from the sun. Period: 687 days Rotation: 24 hours, 37 minutes 2 Moons Geologically active Volcanoes: Olympus Mons Water is trapped at ice caps

How old would you be on another planet??? In class math applications activity