Week 3 notes

Week 3 notes - (about July 4 94.5 million miles away o...

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1/29/08 Earth-Sun Relationships Chapter 2, p. 42 & 48-57 - The approximate size and shape of Earth have been known since about 200 BC. o ancient Greeks (Aristotle) determined Earth to be round due to the curved shape of Earth’s shadow on the moon during a lunar eclipse - However, Earth was thought to be the center of the universe such that other planets and the sun revolved around Earth – egocentricity - idea that all planets revolve around Sun ( heliocentricity ) put forth by Polish astronomer Copernicus in 1543 Earth-Sun Motions - Earth has 2 motions 1. Rotation around an axis (1/24 hours) 2. Revolution around the Sun (1/365.25 days) Earth rotates on its axis and revolves around the sun in a counterclockwise direction when viewed from above (downward onto the North Pole) - Due to an elliptical orbit of Earth around the Sun, the Earth is nearest to the sun at perihelion (about Jan. 3, 91.5 million miles away) and farthest away at aphelion
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Unformatted text preview: (about July 4; 94.5 million miles away) o average Earth-Sun distance is approximately 93 million miles away Earth’s seasons are related to the amount of solar energy received at the surface, which is determined by two variables: 1. the angle at which sunlight strikes Earth’s surface 2. the amount of time that the Sun is above the horizon-Radiation striking Earth perpendicularly is much more intense than radiation striking at an angle [but covers less area]-Incoming solar radiation, termed insolation , is absorbed, scattered, and reflected within Earth’s atmosphere-So, the higher the sun is in the sky and the longer it is above the horizon, the more energy Earth receives.- Earth is tilted 66.5 degrees from the plane of its orbit around the Sun ( plane of the ecliptic ) or 23.5 degrees from the perpendicular to the orbital plane...
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This note was uploaded on 04/03/2008 for the course GPH 111 taught by Professor Ellis during the Summer '08 term at ASU.

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