1. Ch. 28.1 The Moon MARQUES

2. Terms to Know…  Satellite: a body that orbits a larger celestial body  Moon: A natural satellite to a planet  Apollo Missions: 6-manned spacecraft sent to the moon between 1969-1972 by the US  Artificial satellite: man-made objects orbiting the Earth.  1 st artificial satellite – SPUTNIK, launched in 1957 by Soviet Union  1,000 are orbiting around Earth now

3. What is the Moon like?  1/6 (less) gravity than earth. Astronauts bounced vs. walked.  No atmosphere & less dense than earth  Varying surface temps. (day = 134° / night = 170°)  Sides = one faces earth (near side) / other faces away  Covered w/ dust & crushed rock (1-6m deep) known as regolith  Dark areas – known as mare (plural = maria) named for seas by Galileo  Layers = crust, mantle, core

4.  Wobbly rotation – b/c core is not completely solid or liquid  No overall magnetic field  Craters – bowled-shaped depressions caused by debris hitting the moon when S. System was formed  Billions of years old What is the Moon like? CONTINUED…

5. Giant Impact Hypothesis  Scientists believe that more then 4 BYA, Mars-sized object collided w/ Earth  Earth was molten then & mantle chunks were tossed into orbit  These chunks formed out MOON

6. Formation Facts  Differentiation – densest materials moved to the center making a core. Lighter material formed a mantle and crust.  Meteorite Bombardment – debris left over from the formation of the solar system struck the solid surface and formed regolith & craters.  About three bya, the amount of debris decreased. The moon hasn’t changed much since then.  Lava flowed on the moon, especially the near side. The moon cooled about three bya.