The sun has produced energy for billions of years.
Solar energy is the solar radiation that reaches the earth.
Solar energy can be converted directly or indirectly into other forms of energy, such as heat and electricity. Solar energy is used for heating water for domestic use, space heating of buildings, drying agricultural products, and generating electrical energy. In the 1830s, the British astronomer John Herschel used a solar collector box to cook food during an expedition to Africa. Now, people are trying to use the sun's energy for lots of things. Electric utilities are are trying photovoltaics, a process by which solar energy is converted directly to electricity.