Chapter 19, Section 4Earth’s Moons Monday, May 3, 2010 Pages 659 -- 664
Objectives • Describe how scientists have used the telescope to study the moon. • Explain what scientists learned about the moon from space exploration. • Describe the origin and structure of the moon.
Vocabulary Words • Telescope • Crater • Maria
Structure and Origin of the Moon • The moon is 3,476 kilometers in diameter (slightly less than the distance from California to New York). • The moon’s density is about the same as Earth’s outer layers.
Structure and Origin of the Moon -- cont’d • The theory that makes most sense is the collision theory. • Estimated to occur about 4.5 billion years ago.
Telescope • Developed the first telescope. • An instrument that makes distant objects appear closer. • Enabled us to see moon’s surface including craters, highlands, and maria. Italian Astronomer, Galileo Galilei, 1609
Moon’s Craters • Craters are round pits found on the surface of the moon. • Craters on the moon were most likely caused by the impacts of meteoroids.
Moon’s Highlands • Highlands are also called mountains. • The peaks of the highlands and the rims of the craters cast dark shadows. Highlands or mountains
maria • Dark, flat areas are called maria. • Galileo once thought that these dark, flat areas were bodies of water (latin word for seas). • We know now that maria are low, dry areas that were once flooded with molten material.
Moon Missions • Most of the moon missions occurred between 1964 and 1972. • Neil Armstrong was the first person to step foot on the moon.
Moon Rocks and Moonquakes • Much of what scientists have learned about the moon came from detailed study of the moon rocks gathered by astronauts.
Review • Name the three kinds of features that Galileo saw on the moon’s surface. • What did the Apollo astronauts do on the moon? • How did the craters form on the moon?
Homework • Workbook 19.4 (5/5) • Vocabulary quiz 19.4 (5/5)