Solar Energy | Introduction
Introduction
Sunlight has been recognized as a powerful source of energy since ancient times. "Burning glasses" that dated back to 7 B.C. have been found in the ruins of Nineva (now part of Iraq). These glasses were similar to magnifying lens and could concentrate sunlight into a beam hot enough to start a fire. Each day, Earth receives about 4 quadrillion kilowatt-hours of solar energyAny form of electromagnetic radiation that is emitted by the Sun., generated by nuclear reactions deep inside the Sun's mass. While we receive a lot of solar energy, it is not easy to harness. Environmental concerns and our limited supply of fossil fuels make finding ways to gather and concentrate solar energy efficiently an urgent challenge.