So how much longer will the Sun be alive? Is it nearing its death? Is it still a baby in astronomical terms? Well, there is no need to worry because the Sun is going to be around for a few more billions of years. So we will be dead for millions and millions of years before the Sun even starts dying. Astronomers have made estimates asserting that the Sun will more likely continue on as a main sequence star for yet another five billion years before anything substantial starts to change. After about 5 billion years, it will bloat up and turn into a red giant and then slowly shrink down and become what is called a white dwarf.
The Sun is already 4.6 billion years old. At least this is what the astronomers say. They are the experts on this field so we’ll have to take their words for it. Actually, everything in the Solar System like the planets, moons and asteroids appear to have developed together, when a giant cloud of gas and dust collapsed. The Sun and the planets were products of this great collapse. Astronomers have used the amount of radioactive elements present in meteorites that have fallen into the Earth in determining the Sun’s current age.
After the collapse, a few hundred million years later, the Sun turned into its current state as a main sequence star. Atoms of hydrogen then merged with atoms of helium inside the Sun’s hot core. This process involved tremendous heat and pressure so energy in the form of gamma radiation was released. The process has been happening for the last 4.6 billion years which the Sun’s current age. And it is estimated that it will continue doing so for another 5 to 6 billion years.
When these 5 to 6 billion years come to pass, the Sun will eventually start running out of usable hydrogen fuel in its core. This will be the beginning of its slow death. As we stated earlier, it will bloat and become a red giant star, consuming the planets of the Solar System in the process. It will then slowly expand, contract and become a white dwarf, which is basically a dead star.