Solar Energy, radiation produced by nuclear fusion reactions deep in the Sun's core. Solar energy travels to Earth through space in discrete packets of energy called photons (“Solar Energy”). A Photon is defined as a packet or quantum of a wave-like fluctuations in electric and magnetic fields traveling through free space or a material medium (“Oxford Paperback Encyclopedia”).
The simplest example of solar energy use is your calculator. As long as there is light in the room, the calculator will always work by converting light into useful energy. The solar cells on a calculator are called photovoltaic cells and are made of semiconductors, like silicon (“Solar Energy”).
On the side of Earth facing the Sun, a square kilometer at the outer edge of our atmosphere receives 1,400 megawatts of solar power every minute. Only half of that amount reaches Earth's surface. The amount of light that reaches any point on the ground depends on the time of day. The total radiation power varies only slightly, about 0.2 percent every 30 years. Any considerable change would alter or end life on Earth ("Solar Energy”).
Greenhouses and solariums are common examples of the direct use of solar energy, having glass surfaces that allow the passage of visible light from the sun but slow down the escape of heat and infrared energy
The advantages of solar energy
Solar energy has the following advantages over conventional energy:
The energy from the sun is virtually free after the initial cost has been recovered.
Depending on the utilization of energy, paybacks can be very short when compared to the cost of common energy sources used.
Solar and other renewable energy systems can be stand-alone; thereby not requiring connection to a power or natural gas grid.
The sun provides a virtually unlimited supply of solar energy.
The use of solar energy displaces conventional energy; which usually results in a proportional decrease in green house gas emissions.
The use of solar energy is an untapped market.