Stars are made up of hydrogen that comes together from nebulas of gas and dust. The atoms of hydrogen combine together and form helium atoms, creating energy in the form of radiation.
Why Do Stars Die?
Stars can remain stable for billions of years, but the hydrogen fuel must run out at some point. That is when another reaction appears, causing helium atoms to fuse together and form heavier elements, like carbon and oxygen. Eventually, the star runs out of helium too and starts contracting down into a white dwarf.
How Will Our Sun Die?
Since our galaxy’s sun is also a star, it will certainly die at some point, too. Here is a picture of the evolution of the sun:
The evolution of the sun is certain to bring an end to life on Earth as well, long before it will reach its red giant stage. As the sun’s luminosity increases, it will provide enough heat to our planet to bring our oceans to a boiling temperature, which will surely kill all of humanity.
When the sun becomes a red giant, long after life on Earth ceases to exist, our planet will most likely be swallowed. While the inner regions contract and heat up, the outer layers of our galaxy’s sun will expand 100 times their current diameter, engulfing Earth in the process.
When a star like our sun reaches the end of its life, it starts shedding its outer layers into space, resulting in a protoplanetary nebula, like the Egg Nebula in the picture below. This phenomenon happens due to the reactions in the star’s interior that generate stellar winds.
After the red giant stage, our sun will become a planetary nebula centered around a white dwarf. The most common form for planetary nebulae consists of two opposing jets, like the Twin Jet Nebula in the following picture:
After surpassing the nebula stage, our sun will become a white dwarf. It will still have high temperatures, due to residual heat, and its light will be dimmed considerably. In time, white dwarfs cool off and, as scientists assume, they eventually become black dwarfs. The existence of os black dwarfs is still debated, as the universe is not old enough for any star to reach this stage.
Jasmine holds a Master’s in Journalism from Ryerson University in Toronto and writes professionally in a broad variety of genres. She has worked as a senior manager in public relations and communications for major telecommunication companies, and is the former Deputy Director for Media Relations with the Modern Coalition. Jasmine writes primarily in our LGBTTQQIAAP and Science section.