Earth
Steven Dutch, Natural and Applied Sciences, University
of Wisconsin - Green Bay First-time Visitors: Please visit Site
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Earth: Vital Statistics
- Average distance from Sun 93,000,000 miles
- Closest to Sun (perihelion) 91,500,000 miles about Jan. 3
- Farthest from Sun (aphelion) 94,500,000 miles about July 4
- Rotates on axis in 24 hrs., revolves around Sun in 365.2564 days.
- Diameter: through equator 7928 miles; through poles 7899 miles
- Difference is due to centrifugal force of earth's rotation (at equator, centrifugal
force is about 3/1000 as much as Earth's gravity)
- Surface area: 198,000,000 square miles, of which about 50,000,000 is land.
- Mass: 6x1027 grams or 6,000,000,000,000,000,000,000 (6x1021)
metric tons
- Of the Earth's mass:
- about 1/3 is in the core
- 2/3 in the mantle
- 4/1000 in the crust
- 2/10,000 in the oceans
- 1/1,000,000 in the atmosphere
- 1/100,000 in ice caps
What Makes the Earth an Unusual Planet
- Life (based on carbon--over 3 million species)
- Atmosphere (79% nitrogen, 20% oxygen, 1% argon, variable amounts of water vapor, carbon
dioxide)
- Presence of Large Amounts of Liquid Water
- Very Active Geologically
- Active erosion by water
- Plate tectonics--metamorphism, deformation, granitic rocks
- Few impact craters visible
- Strong Magnetic Field for Such a Small Planet
- Has an Unusually Large Satellite in Proportion to Its Size
References
- Raymond Siever, 1975, The Earth. Scientific American, vol. 233, no. 3, pp. 82-91
- Raymond Siever, 1983, The Dynamic Earth. Scientific American, vol. 249, no. 3, pp. 46-55
- Kasting, James F.; Toon, Owen B.; Pollack, James B., How climate evolved on the
terrestrial planets Scientific American, v.258 p90-7 February 1988
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Created 20 May 1997, Last Update 2 Jun 1997
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