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Unformatted text preview: Question 3 - What causes seasons? What makes days longer in summer than in winter? Use fact #3 - rotation axis is tilted from orbital plane by 23.5 degrees Earth's rotation vector points towards Polaris and is fixed there Changes angle at which sun's rays strikej different parts of Earth's surface Extreme of North Pole and South Pole In far North during summer doesn't get dark at all. Seasons produced by combination of tilt of Earth's axis and the revolution about the sun. No tilt = no seasons Summer solstice is June 21 = longest daylight of year in far Northern hemisphere Winter solstice = December 21 = shortest daylight of year in far Southern hemisphere Fall and spring equinoxes Spring equinox = March 21 Autumn equinox = September 23 Why different stars in summer and winter? Can't see stars located behind sun. Phases of Moon not Earth blocking sunlight from Moon - this only happens during eclipses...
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This note was uploaded on 02/20/2008 for the course ASTRO 1 taught by Professor Brandt during the Spring '99 term at Penn State.
- Spring '99