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