The sun formed about 4.6 billion years ago as a result of the decay of gravity of an area within a large molecular cloud. Most of the material gathered in the center, while the remaining discs memimpih be circulating that would become the Solar System. The mass of the hot and dense center and eventually start a thermonuclear fusion in its core. It was alleged that almost all the other stars are formed by a similar process. Classification of the Sun, based on the class spectrum, is a main sequence G (G2V) and is often classified as a yellow dwarf because of the radiation seems to be more intense in the yellow-red portion of the spectrum. Although the color is white, from the surface of the Earth the Sun looks yellow because of the intermingling of blue light in the atmosphere. [16] According to the spectral class label, G2 indicates its surface temperature of approximately 5778 K (5505 ° C), and V indicates that the Sun, like other stars, is main sequence, so that the energy created by the nuclear fusion of hydrogen nuclei into helium. At its core, the Sun fuse together 620 million metric tons of hydrogen each second.
