Chapter+11

=Earth= __Spherical Shape__ Early sailors noticed that the tops of approaching ships appeared first on the horizon and the rest appeared gradually, as if coming over a crest of a hill(curve).
 * Aristotle**(Greek astronomer and philosopher around 350 B.C.) - observed the earth cause a curved shadow on the moon during an eclipse.

__What causes changing Seasons?__ Revolution is the yearly orbit around the sun; however, the earth **does not** move around the sun in a perfect circle. Earth moves around the sun in an **ellipse**. __Solstices and Equinoxes__
 * Orbiting the Sun**
 * Solstice** - The day when the sun reaches its greatest distance north or south of the equator. (Winter and Summer)
 * Equinoxes** - Occurs when the sun is directly above Earth's equator. (Fall and Spring)

=Moon= Moon rotation takes 27.3 days, also, it takes about 27.3 days for the moon to revolve around earth. That's why we always see the same side of the moon. __Moon Phases__ __Solar Eclipse__ - Occurs when the moon moves directly between the earth and the sun and casts its shadow over part of earth. __Lunar Eclipse__ - Occurs when the earth moves directly between the moon and the sun and casts its shadow over the moon. __Moons Origin__ Before the Apollo missions, we thought the moon was created in either of three ways. The moon was pulled in by earth's gravity The moon and earth condensed from the same cloud of dust and gas The earth ejected molten materials that became the moon __The Impact Theory__ The moon formed billions of years ago from condensing gas and debris thrown off when earth and a mars-sized object collided.
 * (read from left to right)**
 * The data the Apollo missions gathered leads us to a new theory.**