How will the universe end?

Hey guys it’s me again, and I couldn’t come up with anything to put in this intro so i’ll just leave it like this. Anyway today’s question, well one of them, was inspired by a user known as Elusus, I received this message today via the contact page “Can you write a post on the life time of a star and how the ending of stars would effect the earth, thanks”.

So this got me thinking and as you can see the title of this post is not the same as the question Elusus asked, the reason I have changed it slightly is because I thought that the ending of all stars would be the at the end of the universe. So we’ll first look at the life cycle of a sun, let’s take our sun for an example, our sun is a medium sized star and it ‘works’ by compressing hydrogen into helium in a fusion reaction. Now the sun is very large and has a massive mass, meaning it has a lot of gravity, but the sun does a large balancing act. As the fusion takes place, a lot of energy is expelled and is sent outwards so this, in turn, counter acts the force of gravity making the the sun stable.

However the sun will eventually burn out all of it’s hydrogen, this will be in a few billion years, however it will happen and when it does the sun will start to burn it’s outer layer. It will then do this until it eventually becomes about the size of Earth (much smaller than it’s original size), although it will only be half of it’s original mass, meaning it will be extremely dense. Anyway by this time the Earth will be long gone and so will any chance of life on it, but what about the universe, what will be the last things left?

Very large suns die quickly and explode in violent super nova’s or turn into black holes, I’ve just explained what a medium sized star will do, so what will a smaller star do. It will basically do the exact same as a medium sized star but calmer and slower, these red dwarfs slowly burn out over trillions of years and form white dwarfs. These white dwarfs are the things that will last the longest along with black holes. Then eventually these white dwarfs will turn into black dwarfs and the universe will be a cold, dark, lifeless place, where nothing new will ever happen and never could happen. Although these events are so many billion years away that in our lifetime it really does not matter and it is nothing to worry about.

Thank for reading guys and thanks to Elusus for sending in this request, I hope you all enjoyed this post and if you did be sure to leave a like and follow for more.

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