Monday, June 21, 2010

The Suns Life Cycle

The sun has billions of years behind and ahead of it. About 4.6 billion years ago it began like other stars, as a cold mass of hydrogen and helium – the solar nebula left over from the big bang. The gas cloud began to shrink under its own gravity and, as it collapsed, the temperature of the core rise from frictional heating as gas molecules collided. When the temperature reached about 10 million .C the thermo nuclear reaction began.
The sun has about another five billion years of life ahead of it, as it turns hydrogen into helium in its core. When the hydrogen fuels runs low, it will burn some of the helium nuclei, fusing those into heavier nuclei. But at the same time it will swell into a giant red star, whereupon the Earth will be destroyed. Only a few million years after that, the sun will puff off some of its out layers and then shrink into a white dwarf, with an intensely hot surface, but so small that it gives out little light. It will then cool off for the rest of time.