astronomy Sun, star around which Earth and the other components of the solar system revolve. It is the dominant body of the system, constituting more than 99 percent of its entire mass. The Sun is the source of an enormous amount of energy, a portion of which provides Earth with the light and heat necessary to support life. The Sun is classified as a G2 V star, with G2 standing for the second hottest stars of the yellow G class of surface temperature about 5,800 kelvins K and the V representing a main sequence, or dwarf, star, the typical star for this temperature class. G stars are so called because of the prominence of a band of atomic and molecular spectral lines that the German physicist Joseph von Fraunhofer designated G. The Sun exists in the outer part of the Milky Way Galax Read More