Universe is a big place. And I do mean *big*.  It is speculated that it might or might not be infinite, but for us it might as well be infinite because of it's unfathomable size. Even light which is the fastest thing that exists takes a lot of time to travel from point A to point B in the universe. Due to this, there are many little fun-facts. For example, it takes light 8 minutes and 20 seconds for light to reach Earth from the sun. Which means that if the Sun was to mysteriously vanish, we would not notice it until after those 8 minutes and 20 seconds. Another fact that I have always found very interesting is that if you were to look at earth from a point that is 65 million light years away, you would find dinosaurs to be still roaming the earth. This is because the light that left the earth 65 million years ago is now 65 million light years away. It is due to this humongous size of the universe that most of the stars that you see in the night sky probably died many, many years ago.

So how could such a big place.... *end*? What happens exactly? Does it all end in a bang, or does it end with nothing but a whimper? Well, we can only theorize. I have gathered some of the most plausible theories here for your viewing pleasure. Let me know what you think of them.

*  # Big Rip

https://3c1703fe8d.site.internapcdn.net/newman/gfx/news/hires/2015/newmodelofco.jpg

[Image source](https://phys.org/news/2015-06-cosmic-stickiness-favors-big-rip.html)

We know that the universe is expanding. This is resulting in the increase of distance between galaxies and their moving apart. But the galaxies themselves are not "torn up" because the force of gravity keeps them together.

In the Big Rip theory, the expansion of the universe accelerates to such an extent that even the galaxies are torn and they move far apart. Initially this applies only to the objects like galaxies but soon with the increase of the expansion, stars, black holes and even planets are broken down because their gravity cannot hold them together any longer. Until finally it comes down to atoms. You guessed it, they too are torn apart. At this stage the expansion of the universe over takes the speed of light. Once that happens, no particle can interact with any other particle anymore. So in the end, the universe is nothing but full of single particles that can never interact with each other. At least that's what this theory says.

* # Big Crunch

http://s.hswstatic.com/gif/big-crunch-theory-big-bounce.jpg

[Image source](http://science.howstuffworks.com/dictionary/astronomy-terms/big-crunch6.htm)

This theory is basically the reverse of the metric expansion of the universe. Instead of the eternal-expansion, the expansion of the universe will come to a full-stop at a certain point. Then the gravity between all of the objects in the universe will bring them closer to each other. This will continue until all of the galaxies and the planets and the stars are eventually packed up into a black holes, which will then in turn combine to form a super-supermassive black hole that contains all of the mass of the universe.

This will all end in a Big Bang. A reformation of the universe, if you will. And the universe will start anew. This is one of the more relatively "happier" and "upbeat" endings for the universe but scientists today suggest that it also might be unlikely.

* # Heat Death

https://www.nasa.gov/sites/default/files/images/729665main_A-BlackHoleArt-pia16695_full.jpg

[Image source](https://www.nasa.gov/mission_pages/nustar/multimedia/pia16695.html)

If we want to understand how this scenario might work, we need to understand entropy first. Everything in the universe tends to move from a ordered state to a state of chaos. I won't even try to explain it here because Brian Cox explains it oh so much better with an amazing example in this video:

https://www.youtube.com/watch?v=uQSoaiubuA0

As the universe expands, the matter moves to a state of high entropy, decays and spreads everywhere. Eventually the molecular clouds - inside which the formation of stars takes place - are exhausted. Because there are no new stars being formed, the universe turns dark. Soon, the black holes start to evaporate. And after an incredibly long period of time every black hole in the universe is evaporated. Nothing exists any more and the universe is dies. This is so, so, *so* far away that for our purposes it may not even happen at all. Although, at this point the heat death of the universe seems most likely the ultimate fate of the universe.

I'd like to say that we cannot possibly know *exactly* how the universe may end or even began. If we are going to go with a theory, lets go with the happiest one. Otherwise, what's the point of being happy, or even being alive if in the end all it comes down to the supreme laws of nature.

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# NOTE:

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One thing I'd like to add is that we are alive at the best possible time for mankind. Every year there is something ground-breaking in the world of science. New phenomena and things are being discovered every second. And with the kinds of tools we have and the kinds of tools we have the ability to develop, keeping in view the amount of mysteries the universe holds in itself, I'd say that we live in extraordinarily exciting times. To say anything less would honestly be a lie. I hope you enjoyed this article. Don't forget to leave your comments and follow me for future content. Thanks!