Chapter 12 1 Earth in space Earth Moon

+ Chapter 12. 1: Earth in space Earth, Moon & Sun

+ Standards n 8. 4. e. Students know the appearance, composition, relative position and size, and motion of objects in the solar system, including planets, planetary satellites, comets, and asteroids.

+ Astronomy n. The study of the moon, stars, and other objects in space is called astronomy.

+ How the earth moves n. Earth moves through space in two major ways: rotation and revolution.

+ Rotation v. Revolution n. Rotation: The spinning of the earth on its axis n. Axis: imaginary line through the North and South Poles

+ Rotation v. Revolution n Revolution: movement of one object around another n Orbit: Earth follows a path as it revolves around the sun. It is a slightly elongated circle, or an ellipse.

+ Calendars n. Calendar: system of organizing time that defines the beginning, length, and divisions of the year. n. Egyptian: discovered there were 365 days in a year n Had 12 months with 30 days each, and 5 days left over n. Romans: borrowed Egyptian calendar, but added the leap year.

+ Seasons n. How n. Hits sunlight hits earth right at the equator n. Earth has seasons because its axis is tilted as it revolves around the sun

+ Seasons Picture

+ Seasons n Earth in June n Northern hemisphere: hot n Tilting towards the sun n Southern hemisphere: cold n Earth in December n Northern Hemisphere: cold n Southern hemisphere: hot n Tilting towards the sun

+ Solstices n. Solstice: day when the sun is farthest north or south of the equator n. Here: Summer Solstice is the longest day, Winter Solstice is the shortest day of the year

+ Seasons Picture

+ Equinoxes n. Halfway between solstices, we have equinoxes. n. Equinox n. Spring = “equal night” and Fall equinoxes mean that the day is as long as the night

+ Seasons Picture