According to calculations of modern astronomers, the Sun will exist as it stands 5 billion more years. Without it life on Earth cannot long exist, and arise - especially.
The sun went out
If to include imagination and to arm with some knowledge, it is possible to assume what will be when the Sun goes out. Solar energy - the prime cause of emergence of life on Earth. It starts many processes happening on our planet vital for all organisms.
At once after the termination of revenues to the Earth's surface of energy of the Sun, it will begin to freeze gradually. Within 45 days the planet will finally become covered by a thick ice layer. The land, especially the regions far from water sources will be the first. The seas and oceans will be a final resting place of solar energy on the freezing Earth, its most part is absorbed by the hydrosphere. Temperature in the ocean even at a depth of 35 meters is about 15 degrees. Plants will die in several days.
Accident will induce people to look for alternative sources of heat. Greenhouse effect can serve as one of them. The infrared radiation going from the surface of the planet will be late some time clouds, without allowing it to cool down. But clouds will disappear through short time as water due to the lack of solar energy will not evaporate any more. Perhaps, people will begin to burn the wood that greenhouse effect arose because of high concentration of carbon dioxide in the atmosphere. Also minerals and nuclear fuel can be power sources. But the mankind will lose the main element necessary for maintenance of life - oxygen which was produced by plants. It is necessary to create an artificial environment for their cultivation. Rescue for some people will be possible if they depart to space. However modern technologies will not allow them to be there very long. They will find the final resting place in space.
Evolution of the Sun
All above-mentioned - only model, possible provided that the Sun will really go out. It is possible only through 5 billion years when all hydrogen - the main source of thermonuclear energy thanks to which there are all processes inside and on a star surface disappears. Before it occurs, the Sun will give inhabitants of Earth an unpleasant surprise. A final chord of his life as the source of heat will become transformation into the red giant. Its temperature will increase several times that will harmful affect Earth: oceans will begin to boil, the land will turn into the burned waste ground. Then the star will turn into the white dwarf.