Every day, the sun radiates (sends out) an enormous amount of energy—called solar energy. It radiates more energy in one day than the world uses in one year. This energy comes from within the sun itself. Like most stars, the sun is a big gas ball made up mostly of hydrogen and helium gas. The sun makes energy in its inner core in a process called nuclear fusion.
It takes the sun’s energy just a little over eight minutes to travel the 93 million miles to Earth. Solar energy travels at the speed of light, or 186,000 miles per second, or 3.0 x 108 meters per second. Only a small part of the visible radiant energy (light) that the sun emits into space ever reaches the Earth, but that is more than enough to supply all our energy needs.
Every hour enough solar energy reaches the Earth to supply our nation’s energy needs for a year! Solar energy is considered a renewable energy source due to this fact. Today, people use solar energy to heat buildings and water and to generate electricity. Solar energy is mostly used by residences and to generate electricity. Go Solar Today!
Energy From The Sun
About half the incoming energy from the sun is absorbed by water and land; the rest is re-radiated back into space. Earth continuously receives 340 Wm-2 of incoming solar radiation (insolation) at the upper atmosphere.
Approximately 30% is reflected back to space while the rest is absorbed by the atmosphere, oceans and land masses. After passing through the atmosphere, the insolation spectrum is split between the visible and infrared ranges with a small part in the ultraviolet. Go Solar Today!
The absorption of solar energy by atmospheric convection (sensible heat transport) and evaporation and condensation of water vapor (latent heat transport) powers the water cycle and drives the winds. Sunlight absorbed by the oceans and land masses keeps the surface at an average temperature of 14 °C.
The conversion of solar energy into chemical energy via photosynthesis produces food, wood and the biomass from which fossil fuels are derived.
Solar radiation, along with secondary solar resources such as wind and wave power, hydroelectricity and biomass, account for over 99.9% of the available flow of renewable energy on Earth. The flows and stores of solar energy in the environment are vast in comparison to human energy needs. Go Solar Today!