So this is how it ends.

4.5 billion years ago a miracle of creation and science took place in this big ol' universe of ours when violent bursts of radiation or shockwaves from a nearby supernova, or exploding star, caused a gravitational collapse within a giant molecular space cloud and caused the cloud to break into smaller chunks. Some of these resultant pieces began to heat up and form protostars, forming a dense core where hydrogen, helium and other heavier trace elements fuse in a chemical reaction that generates staggering amounts of light and energy for billions of years.

A star is born.

Our Sun.


Hydrogen is the fuel that keeps the Sun burning and is steadily converted into helium through nuclear fusion, carrying energy away from the core through a combination of radiation and convective processes keeping the star stable and preventing it collapsing in on itself. At present there's a mix of around 75% hydrogen to 25% helium and a good balance of gravitational forces so there's plenty of life left in the old girl. Each second, more than 4 million tonnes of matter are converted into energy within the Sun's core.

In 3.5 billion years from now the hydrogen will be running out and the temperature will have risen by around 10%. The end will begin for our Sun. By this point mankind will have had to have left the Earth as the temperature here will be around the 2000C mark. 2 billion years later the hydrogen will have been exhausted and the Sun will start to burn helium instead. At around 10,000 times its current brightness and 80 times its current diameter (swallowing her nearest neighbour, tiny Mercury) her surface temperature will be in the region of 3,500C and she will no longer burn white but red as she becomes a Red Giant.


Betelgeuse star - a red supergiant nearing the end of it's life

Thankfully the Sun's gravitational pull will diminish the larger she becomes so Earth, and indeed Venus, will survive the massive expansion by being pushed into higher orbits. Despite this narrow escape from annihilation the Earth will be dead, her oceans having boiled away to nothing and the atmosphere will have been blown away by solar winds. Life on Earth will no longer exist. In any form.

In 6.5 billion years the Sun will begin to break up and expulsions of gases will signal her transition into a planetary nebulae. Now surface 'winds' will reach 6 million km/h and free floating clouds will be formed by gas breaking free.


The crab-nebulae - remnants of a supernova

Eventually, when all energy has been used and the Sun has burnt away her surface to leave only a dimly glowing core, the Sun will shrink to about the same size as Earth and become a white dwarf.


An artists impression of a White Dwarf

Millions of years later the fuel will be all but exhausted. Because she is no longer generating the necessary energy to keep the gravitational pull in balance she will become denser and smaller until roughly a millionth of her present size. She will gradually cool, her energy will wane and she will eventually emit no light. The Sun has become a black dwarf.

The Sun is now dead.