Who doesn’t like to daydream about the future? We’re all guilty of imagining the moment when we inevitably win the lottery, become a world-famous singer, or tell our horrid boss where to stick it. Don’t deny it, we know that you do it too.
Scientists like to daydream too, but unlike your PG-18 dream about Chris Evans, their projections are grounded in reality. Or at least what we know of reality as of right now. Based on what we already know, scientists are starting to get an idea of what might happen to our universe in the future.
What Comes After Us?
What will happen to the universe long after the Sun has become a red giant and scorched the Earth? (Unfortunately, that’s most likely going to be a thing. But don’t worry, we won’t be here to witness it.)
The ultimate future of the universe has been theorized about for years, and each new scientific breakthrough brings us half a step closer to the truth. Even then, guessing is all anyone can do, considering this won’t happen for billions of years. But who doesn’t love a good theory about the end of times?
Suspend your disbelief, take that big grain of salt, and imagine yourself hibernating for a whole lot of years. Assuming you go to sleep now and wake up close to when the credits roll, here are some of the exciting things you might see before everything goes bye-bye.
#3: The Big Crunch – “Groundhog Day” in Cosmic Proportions
If you’ve never seen Groundhog Day, your whole hypothetical hibernation might have started even prior to this article, because you’re missing out.
The movie, starring Bill Murray and Andie McDowell, depicts a weatherman who is stuck in a time loop, reliving the same day over and over. That’s essentially what one part of the Big Crunch is about – the universe being an infinite cycle.
Let’s start from the beginning. The very beginning.
The most widely accepted theory about the creation of our universe is called the Big Bang, which was a wild period in the history of space and time. The Big Bang brought the creation of literally everything – the stars, planets, galaxies, and even you. Apparently aside from our parents, even the universe had to bang for the sake of our existence.
Many assume that before the Big Bang, nothing existed… not even time.
But what if it wasn’t the first or the last time that our universe was created?
That’s where the Big Crunch comes in.
According to one version of this theory, the universe undergoes endless cycles of coming alive with the Big Bang. It expands over billions of years as gravity pushes galaxies far apart. And then, when it’s impossible for the universe to expand any further, it begins to constrict, rapidly pushing those stars, galaxies and black holes back together. This is what we call the Big Crunch – the universe re-collapsing on itself.
Witnessing the collapse
If by some miracle we were still alive to witness the beginning of the Big Crunch, our corner of the universe would suddenly become densely populated, just like it was right after the Big Bang. Stars and galaxies would litter our sky day and night, assuming we’d still have periods of darkness with this much light surrounding us.
Sounds pretty cool, right? Well, not exactly. Aside from the sky being pretty, it would also be deadly. The stars would collide, as would planets. Assuming we survived that, our very own Earth would still be in trouble, as the temperatures would rise. Oceans would boil and mountains would melt, and the universe would keep on constricting.
Eventually, it would end as it began – with a bang. And that might be the end of it, but it might also not be.
After the Big Crunch
This theory supports two outcomes, one of them being that the universe implodes and then dies. It’s also possible that everything would become one incredibly massive black hole. The second outcome is that the collapse causes a reformation of the universe, starting with another Big Bang.
If the second theory is the right one, it means that our universe might be stuck in an infinite cycle of exploding, expanding, and then exploding once again. Another version of this cyclical model of our universe is referred to as the Big Bounce.
#2: The Big Rip – the Thanos theory
Have you ever seen Avengers: Infinity War? Are you still traumatized by Thanos, the big, purple scrotum-chinned bad guy in the movie? With just a snap of his fingers (and a set of Infinity Stones), he was able to destroy half the living beings in the universe. If you replace Thanos with dark energy, and poor Peter Parker with the entire universe, you’ll have yourself a Big Rip. But how does it actually work?
Remember how we said the universe was expanding? Yeah, that’s actually not just a theory. The universe is expanding at an accelerating rate, and that expansion could lead to a few different outcomes. One of them is known as the Big Rip.
In this theory, the force that stands behind our ultimate demise is called dark energy. While it sounds like something pulled straight out of Star Wars, we don’t actually really know what it is yet. Its very existence is still somewhat hypothetical, but assuming it does exist, it’s believed to be constantly increasing. It’s already very prominent in space – about 68% of the energy present in the universe is referred to as dark energy.
But what does dark energy have to do with the Big Rip?
If we assume that dark energy exists and is always increasing without limit, it could overcome all the forces that hold our universe together. If it managed to overwhelm gravity, it would be strong enough to bring the universe to an end.
As dark energy would increase and begin to defeat the forces of gravity, the expansion of the universe would continue accelerating. Galaxies would be flying apart everywhere, and the gaps between them would grow to be unimaginably huge. At some point, the dark energy would be strong enough to not only push the galaxies, stars, and planets away from each other. It would be strong enough to rip them apart, effectively destroying them.
The final hurrah would be dark energy tearing apart atoms and all matter itself.
What would happen during the Big Rip?
Again, assuming we were there to see it, the Big Rip would likely be much less spectacular than the Big Crunch. In fact, it would be rather sad.
About 60 million years before the Big Rip goes all Thanos on the universe, gravity would stop being able to hold the Milky Way and other galaxies together. Stars would be pulled away from their systems one by one, and the universe would slowly grow dim.
With less and less immediate neighbors, our night sky would not be a lot of fun to look at. In fact, the future of the Earth in this scenario (which in reality would be long gone, just in case you forgot) is impossible to predict. It’s very likely that we would be pulled away from the Sun, or the Sun from us, and the Earth would converge in darkness.
As we would approach the Big Rip, solar systems would become gravitationally unbound, and everything would start to fall apart. In the last minutes of the universe, everything would be torn apart – stars, planets, and eventually atoms. When the Big Rip finally hits, even spacetime itself would be ripped apart. Don’t worry if you can’t wrap your head around that. No one can.
This is the Big Rip – the ultimate destruction of literally everything. Sounds cheerful, right? Well, prepare yourself, because number one on this list is even more depressing than that.
#1: The Big Freeze – who turned out the lights?
The number one on this list is probably the most likely scenario. If you consider that the Big Crunch symbolizes going out with a bang, then the Big Freeze stands for going out with a sad whimper.
As the universe expands, some theories suggest that it might just continue expanding forever. By forever, we mean forever, and not the kind of forever you can usually find in love songs. Big Freeze is a theory in which our universe will continue expanding until the very end.
This theory is similar to both the previous theories in some ways. Dark energy is present here as well, causing the same type of trouble it did in the Big Rip. As it would continue to accelerate the expansion of the universe, the universe would grow colder.
Somewhat in contradiction to this, the Big Freeze is sometimes referred to as the Heat Death of the universe. That term comes from the theory that in the universe, entropy will increase until it hits a “maximum value” of some kind. One theory is that everything in the universe will eventually move from order to disorder. Entropy is the measurement of that.
Long story short, as entropy reaches the maximum, it’s believed that all the heat in the universe would be distributed evenly. There’d be no more room for usable energy, and without it, the universe would reach a standstill.
Like a country suffering from low birth-rates, the universe would be stuck with what it already has. It would continue to expand for billions (or trillions) of years. Stars would die out one after one, leaving their solar systems in complete darkness.
As the universe would continue to expand, the supplies of gas would spread so thin that no new stars could be born. With the old ones dying out over time, and the remaining ones growing far apart, the universe would slowly turn dark.
And you thought the previous scenarios were depressing.
What would we see?
Once again, let’s disregard logic (which says that the Earth has about 7.6 billion years left before the Sun destroys us), and assume we’re all still alive to see the universe die from the Big Freeze. What do we see?
At first, it would be rather cool.
About 4 billion years from now, scientists expect that our galaxy – the Milky Way – will merge with our neighbor, Andromeda. This could be dangerous, as two massive galaxies merging equals collisions. However, it’s also quite possible that we would survive the merge itself. It’s a long process, and it’s already happening.
The sudden increase in the number of our stellar neighbors would, like in the Big Crunch, make our sky really, really pretty. Which is fair, because by the end of this, our sky wouldn’t even exist.
Moving on to anywhere between 100 billion and 1 trillion years from now, our shared galaxy Milkomeda would merge with all the other galaxies around it, creating one large super galaxy. As the universe would keep on expanding, the galaxies would be pulled far enough apart that no new cosmic events would take place.
It’s only downhill from there. As the old stars would die out and no new stars would be born, the galaxies would slowly grow dim. Our own night sky would eventually grow almost completely dark with only little specks of light in the far distance.
As everything would decay, wither and die, the only thing remaining would be black holes, and even those are speculated to disappear at some point.
Eventually – and this is in trillions of trillions of years – the universe would become a black, freezing void. It’s kind of how you felt when your favorite show ended, except worse. That’s what the Big Freeze is all about – a cold, dark ending with no new beginning in sight.
Don’t worry about the fate of the universe.
While it is fun to speculate, no one knows for sure what will really happen billions of years from now. The expansion of the universe is a confirmed fact, but we don’t even truly know what dark energy is – much less how it works. It could be that in ten years, or a hundred, or five thousand, our current theories will be proven wrong.
For now, however, these were the most popular theories about the ending of everything. We hope that this article cheered you up to no end. There’s an upside – if you’re ever bored, just think how boring it would be to witness the universe succumb to the Big Freeze!
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