Solar energy is heat and light radiated by the sun that controls the climate of the Earth and allows the existence of living beings on our planet.
Solar energy refers specifically to the conversion of sunlight into electricity through fuel cells or photovoltaic cells.
Each day the sun radiates enormous amounts of energy, it radiates more energy in one second than mankind has used since the beginning of time.
The energy constantly radiating from the sun comes from the sun itself. Like other stars, the sun is a mass of gases, mostly hydrogen and helium. The hydrogen atoms in the core of the sun combine to form helium and produce energy through a process called nuclear fusion.
During nuclear fusion, high pressure and temperature of the sun cause the hydrogen atoms are separated, and their nuclei combine. Four hydrogen nuclei combine to form a helium atom. The helium atom has less mass than four hydrogen atoms were merged, which is why a certain amount of mass is lost during nuclear fusion. This missing matter is emitted into space as radiant energy.
It takes millions of years for the core energy of the sun reaches the solar surface, and only 8 minutes to travel 149 million miles to earth. Solar energy travels to earth at a speed of 186.000 miles per second, the speed of light.
Only a very small amount of energy that is radiated from the sun into space comes to Earth, a billionth part. Yet this amount of energy is enough solar energy reaching the earth in one day would be enough to supply our planet for a year and a half, that if tapped into effectively.
About 15% of the sun’s energy that reaches Earth is reflected back into space. 30% is used to evaporate water, which rise into the atmosphere produces rain. Solar power plants also absorb and oceans.
The rest of the solar energy is available to us to meet our energy needs (light, electricity, heat, etc.).
Humans have used solar energy for centuries. From the seventh century BC, people used magnifying loupes to focus sunlight into beams so hot they could light fires in the wood.
More than 100 years ago in France, a scientist used heat from the sun to produce steam and jump-start a steam engine.
At the beginning of last century, many scientists and engineers began researching ways to harness solar energy. An important development was a solar water heater invented by Charles Greeley Abbott, an American astrophysicist, in 1936.
Water heating with solar energy was popular in the southeastern United States since the twenties. It was not until after World War II began to growing research in the field of solar energy. This growth lasted until the mid-fifties, when the low cost of natural gas made it the primary fuel for heating homes.
The people and governments remained indifferent to the possibilities of solar energy until the oil shortages of the seventies. Nowadays people use solar energy to heat buildings and water to generate electricity.
If you use solar energy does not generate air or water pollution, and is a huge and free energy source.