Solar Energy
There are two main types of solar energy technologies—photovoltaics (PV) and concentrating solar-thermal power (CSP).
The Sun
The Sun is a sphere of intensely hot gaseous matter with a diameter of about of 1.39 x 10 6 km and is on a distance of about 1,5 x 10 8 km from the Earth. The Sun rotates on its axis about once a month, but it does not rotate as a solid body, rather its equator takes about 27 days and the polar regions take about 30 days for each rotation.
