Lesson Summary

sun_trees
Photo courtesy of John-Morgan/Flickr.

This week you were introduced to the concept that all of Earth's spheres are powered by the sun.
  • Most of the sun's energy is absorbed by planet Earth (70%)
  • A smaller percentage is reflected by into space (30%)
  • Sunlight supplies energy for almost all of Earth's ecosystems. Without it, producers would not be able to do photosynthesis
  • Humans use solar radiation to supply energy for bodily functions, as mitochondria convert glucose into ATP
  • Humans also harness the power of the sun's energy as an alternative, renewable energy source
  • Different materials and topographies either absorb, transmit, or reflect solar radiation
  • The percentage of radiation reflected back into space can be measured as albedo
Last modified: Wednesday, 10 November 2010, 5:19 PM