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Space Unit

Space Unit . EARTH. Earth’s Shape. The Earth is not a true circle, it is a: Oblate Spheroid Bulges in the middle. Why Does Earth Have Life?. 1. Right distance from the Sun 2. Right amount of water 3. Right amount of atmosphere. Earth’s Rotation.

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Space Unit

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  1. Space Unit EARTH

  2. Earth’s Shape • The Earth is not a true circle, it is a: • Oblate Spheroid • Bulges in the middle

  3. Why Does Earth Have Life? • 1. Right distance from the Sun • 2. Right amount of water • 3. Right amount of atmosphere

  4. Earth’s Rotation • The rotation of the Earth lasts for 24 hours. • A rotation is the Earth turning around itself. • http://eoimages.gsfc.nasa.gov/images/imagerecords/57000/57760/rotate_320.mpg

  5. Earth’s Revolution • The revolution of the Earth around the Sun takes 365.25 days. • (which is why we have a leap year every 4 years)

  6. Earth’s Revolution • A revolution is the path the Earth takes in the solar system around the Sun. • http://www.classzone.com/books/earth_science/terc/content/visualizations/es0408/es0408page01.cfm

  7. Earth’s Tilt • The Earth is NOT perfectly vertical. • It’s tilted!

  8. Earth’s Tilt • Not only is the Earth tilted but it wobbles!! • http://en.wikipedia.org/wiki/Precession • The wobble changes which star is our North Star (Polaris to Vega) • This takes 26,000 years

  9. Earth’s Tilt • The Earth’s tilt is 23.5 degrees. • The tilt of the Earth is the reason our planet has seasons.

  10. Seasons • The seasons are a result of two things: • The tilt of the Earth • Earth’s location in its revolution around the Sun

  11. Seasons

  12. Seasons - Spring • Vernal Equinox (equinox=equal) • March 21st • Equally 12 hrsof light and 12 hrsof night.

  13. Seasons- Summer • Summer Solstice • June 21st • 16hrs of light and 8 hrsof night.

  14. Seasons-Fall • Autumnal Equinox • September 21st • 12 hrsof light and 12 hrsof night.

  15. Seasons- Winter • Winter Solstice • December 21st • 8 hrsof light and 16 hrsof dark

  16. Seasons • If we did not have a tilt in the Earth we would not have seasons. What would that be like? • http://www.nasa.gov/multimedia/videogallery/index.html?media_id=161642931

  17. http://astro.unl.edu/naap/motion1/animations/seasons_ecliptic.swfhttp://astro.unl.edu/naap/motion1/animations/seasons_ecliptic.swf

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