How is our universe going to end?
Introduction
Seems like a pretty pessimistic and philosophical question right? Not exactly. Cosmologists have long theorised how our universe is going to end, and surprisingly enough, it’s pretty mathematical.
Don’t worry, you’ll be long dead before any of this begins to take place.
I unfortunately couldn’t find a nice quote so here’s one by me:
“The universe will end”
- Madhav Menon
While this article might seem perfect for nihilists, I mean after all if the universe is going to end anyway, what’s the point, right? Well, to be fair I guess no one knows the answer to that. Regardless, the way the universe is going to end is actually shrouded in mystery. Scientists, however, have theorised different ways, all of which depend on the density of the universe.
Let me back up for a second, how did the universe start in the first place?
The Big Bang
The universe started with the Big Bang, yes it definitely got its name from the TV show. Essentially, astronomer Edwin Hubble was observing some distant galaxies when he found out that these galaxies were moving away from each other (A phenomena known as Redshift), this led Belgian astronomer Georges Lemaître to realise that if the universe is expanding at the moment, it would have been a very tiny ball billions of years ago, in fact it would have been a singularity that would have just exploded.
While it is still a theory, it is accepted by almost every scientist (Some still believe in the steady-state theory). There is also very good evidence for the big bang having taken place: Cosmic Microwave Background Radiation (CMBR), it’s basically remnant radiation from the Big Bang. It’s this radiation that causes the black and white static on your TVs.
Critical density
The death of the universe depends on a number called the critical density, this is essentially the density of matter required to stop the expansion of the universe and result in its end. Another fact is the shape of the universe (This goes a bit into Einstein’s theory of relativity, so for the sake of your sanity I am not going to delve into it.)
The Big Freeze
The Big Freeze is what Scientists currently believe the fate of our universe will be.
Essentially, every object in our universe, whether’s that’s stars or galaxies have two main “forces”, if you will, acting on them. One is the attraction of gravity, trying to clump things together. The other, is dark energy, pulling things away.
As I read in an article, there is essentially a “cosmic tug of war” going on. The winner of this war will also depend on the fate of the universe.
If dark energy manages to slightly overcome the force of gravity, things are going to move away from each other. Galaxy clusters will start to dissolve, planets will move away from their planetary system, and everything will basically just exist in a state of loneliness.
As we’re too far from our natural sources of light and heat, stars, everything is going to become cold and dark. Everything is going to freeze in the cold and empty vacuum of space.
This outcome is also known as the heat death.
Why? Well, if we look at heat energy, it tends to go from a place of higher thermal energy to lower thermal energy (Think of it as being a diffusion of sorts). However, in the big freeze, your thermal energy is kind of distributed evenly. Nothing can flow anywhere.
Our universe would reach a “thermodynamic equilibrium”, and things are going to get cold for a very long time.
This is the bleakest outcome in my opinion.
The Big Rip
Now what if the pulling force caused by dark energy is much greater than the attractive force of gravity? Well things are going to be pulled away from each other a lot harder. Not only is the force of gravity going to be overcome but the other three main forces as well. (Check out my article on the four fundamental forces here)
What does this mean? Well, atoms are gonna be broken up. Matter as a whole will no longer cease to exist as things “rip” into smaller pieces.
We’ll all essentially be “Thanos-snapped” out of the universe, the sad part, nothing is gonna end up in dust as well.
The Big Crunch
This in my opinion, is the most optimistic end for us all, due to something called the Big Bounce.
This Big Crunch occurs when the attractive force of gravity manages to overcome the force pulling everything away.
Things essentially start colliding into one another, forming another small ball, another singularity.
As things start becoming more dense, temperatures start rising. Essentially, we’re back to what the big bang started off like.
So, is it possible another big bang takes place?
The Big Bounce
The Big Bounce is this idea that after a Big Crunch, another Big Bang takes place. This results in another universe forming. It’s possible that our current universe is also the result of a previous big crunch. We have no way of knowing.
This cycle could very well be recursive. If humankind was to die out before the end of the universe, it’s possible that we again manage to come back to life, kind of how we started off in this universe.
So, how is the universe going to end? Scientists estimate we’re going down the Big Freeze line. Again, at the end of the day, only time will tell.
