Earth

Steven Dutch, Natural and Applied Sciences, University of Wisconsin - Green Bay
First-time Visitors: Please visit Site Map and Disclaimer. Use "Back" to return here.

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

Return to Planets Index Page
Return to Earth Science 202 Visuals Index
Return to Professor Dutch's Home Page

Created 20 May 1997, Last Update 09 March 2005

Not an official UW Green Bay site