AST 2003 Lecture Notes - Lecture 3: Lunar Eclipse, The Moons, Ellipse
Document Summary
Astronomy notes 8/30/2016: the earth is on an ellipse, when the earth is closer to earth, it is winter. There is less energy and it tilts away the sun: when the earth is farther from the earth, it is summer. There is more energy and it tilts towards the sun: tilt=season, the earth is about 4. 5 billion of years" old. The moon was part of earth and then start spinning around the earth"s rotation and. Celestial dynamics (chapter 3) reformed: the sun rises in the east and sets in the west, lunar eclipse. The sun is tangent to earth, which creates a great shade area called the umbra. There is also a shade of cone-like structure called penumbra that are on the sides of the umbra. Once the moon enters the penumbra, the eclipse begins and then when it reaches the umbra the moon has a complete eclipse: solar eclipse.
