When and how will the sun die?

Magnificent coronal mass eruption. Credit: NASA, CC BY

 

The sun is a main-sequence star, which means it is in the stage of its life where it is converting hydrogen into helium through nuclear fusion in its core. This process releases a tremendous amount of energy in the form of light and heat, which is what makes the sun shine.

The sun has enough hydrogen fuel to continue this process for about another 5 billion years. Eventually, however, the sun will run out of hydrogen fuel and will no longer be able to produce the energy needed to sustain itself.

When this happens, the sun will begin to die. It will start to contract and become denser, and the increased pressure and temperature in its core will cause the helium to fuse into heavier elements such as carbon and oxygen. This process will produce even more energy, causing the sun to expand and become a red giant.

Eventually, the sun will run out of helium fuel as well and will no longer be able to sustain the fusion reactions that keep it burning. At this point, it will begin to cool and contract again, becoming a white dwarf. A white dwarf is a dense, Earth-sized object that is composed primarily of carbon and oxygen.

The sun's death is still a long way off, and it will be billions of years before it reaches the end of its life. By that time, the Earth will have long since become uninhabitable due to the increasing heat and radiation from the sun's expansion.

As the sun continues to evolve and die, it will go through several more stages. After it becomes a white dwarf, it will continue to cool and contract over a very long period of time, eventually becoming a cold, dark, and dimly glowing object known as a black dwarf. This final stage is thought to be the end of the life cycle of a sun-like star, and it may take trillions of years for a white dwarf to reach this point.

It's important to note that the sun's death is still a very long way off, and it will be billions of years before it reaches the end of its life. In the meantime, it will continue to provide the Earth with the energy it needs to sustain life.

It's also worth mentioning that the sun is just one of billions of stars in the universe, and all stars follow a similar life cycle. Some stars are larger and more massive than the sun and will have shorter lifespans, while others are smaller and will live for much longer. Regardless of their size and mass, all stars will eventually reach the end of their lives and die.