Solar Energy

Solar Energy : Energy From the Sun

Most of us in elementary school learned that the sun is a giant ball of hydrogen and helium, and that it’s big and far away. Basic science courses in astronomy may have also taught you that the sun releases energy through a self-sustaining nuclear fusion reaction. And you may even know a little bit about nuclear physics if you studied science in college. 

But ask the average person how energy flows through the biosphere on earth, or how it can power our homes, and you may come up short.

The laws of thermodynamics describe how energy flows from the sun to (and through) every organism on earth. All the energy of life is provided by the sun, making life a conduit for the continuous flow of solar energy through plants and into sugars, biomass, waste heat, and so on.

The laws that govern solar energy flow are the laws of Thermodynamics (only the first two are really important here):

  1. Energy can neither be created nor destroyed, only change form.
  2. The energy of any closed system is strictly non-decreasing (the law of entropy, or things ‘tending to fall apart’ without an external energy source.
All this says is that life needs the sun to exist, and that each organism is like an island in a river of solar energy.
If you’re here to learn about how solar energy powers our homes via solar power and solar panels, start with these posts: