Plants, animals, humans and the entire ecosystem present on our planet are dependent either partially or completely on Sun as an energy source. If you think more about Sun’s importance in terms of Solar System, you’d see that the Sun’s gravity is responsible for holding Solar System in place. Just imagine, whirling about in space in any random direction, almost freezing to death and wondering how we would revive our collapsing ecosystem. That is a lot like Earth without Sun. So, now you have probably guessed it, we will try to understand what happens when the Sun finally dies in this blog post.
Sun, like all other stars, has a fixed lifespan and definite stages. Currently, the scientists have determined that Sun is in main sequence, the stage in which a star spends most of its lifetime.
A red giant is a dying star in the last legs of stellar evolution. About 4-5 million years later, Sun will expand to become a red giant after completely exhausting the Hydrogen fuel in its core. Its luminosity will increase. In a bizarre manner, the core will shrink and become hotter while the envelope expands and cools. In the process, it will ‘throw off’ its outer layers (called a planetary nebula) and diminish its gravitation pull. Gases/matter ejected by stars during the red giant phase is ionized (process of conversion of atoms/molecules into ions), giving off visible light, and finally becoming a part of ISM. These gases now have the ability to become a part of new stars.
Once the Sun swells, Mercury would be vaporized, next; Venus would be burned and then consumed. The fate of Earth is still being debated by researchers. Some believe soon after Mercury and Venus, it will be Earth’s turn to be sizzled and consumed completely. However, there are some scientists who claim that Sun would stop expanding before it engulfs Earth. Nevertheless, due to the close proximity, it is very certain that life would be wiped out on Earth.
Sun begin helium fusion into carbon when it exhausts the hydrogen; thus, ending up being composed of oxygen and carbon. The Sun doesn’t have sufficient mass to become a black hole or explode in a supernova, therefore in a more mundane turn of events; it would collapse as a white dwarf. It will be very hot when it turns into a white dwarf. Sun, as a white dwarf, would be far smaller than it is now. However it would be very dense. Lack of gravitational compression will stop the process of nuclear fission. Thus, there would be no source of energy; this will cause the hot dwarf to cool down. This process could take trillions/quadrillion of years.
Thereafter, it will finally cool down to a black dwarf, as cold as the space. If the Earth is not swallowed by the red giant, its final fate is to collide with the black dwarf remnant of the Sun.
However, we won’t be around to see the end of Sun. Scientists have noticed an increase in Sun’s luminosity by 6% every one billion years. While this may seem to be a modest increase, it will render Earth uninhabitable in almost one billion years.
What do you think about this article? Let us know in the comments!
FURTHER READING:
The Inner Space Network 
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