There’s been several theories on how the universe came into existence, but how is it going to end? We’re not talking about the apocalypse, though. But chances are it won’t last forever. Nothing does. That’s probably eons from now. We’re asking: what will eventually happen to all the planets, stars, and galaxies in the universe that would be the end of all things? Here are four possible theories.
The End Of Time
The Big Bang model states that the universe is expanding; and despite the fact that nothing travels faster than the speed of light, it takes time for light to travel through space. The light that hit our telescopes take billions of years to reach us. What this means is that, whatever these telescopes pick up in space, are actually old — occurrences that happened billions of years ago. Truth is, galaxies used to be closer together than how we see them today, a phenomenon known as cosmic inflation.
This is evidence that the universe is expanding at an increasing rate, faster today than it was yesterday, and even faster tomorrow. Scientists aren’t really sure what forces are causing this, but have a hypothetical name for it: it’s dark energy — some sort of substance or field that exerts a sort of reverse gravity. This pushes out as gravity pulls in, and this can’t go on forever. So what might happen? Here’s what!
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#1. The Heat Death
Imagine what happens to a smoke as it rises from the burning flame. It dissipates into nothingness, right? That’s the fate of our universe should it experience heat death. In this hypothetical scenario, if there’s enough dark energy in the universe, the cosmic inflation will continue, causing everything to move farther and farther away. As galaxies drift away from each other, stellar formation will come to a halt. Eventually, atomic particles will decay into subatomic particles, causing them to move so far away from each other that electromagnetic forces will seize to interact.
Finally, the universe will be dark, cold, and motionless — that’s why it’s also known as ”The Big Freeze.” The “heat” is in reference to the fact that this results in entropy — … This is the most likely fate for our universe.
#2. The Big Crunch
Let’s assume that dark energy wouldn’t become such a force to reckon with. In this scenario, dark energy would be weakened to a point where it couldn’t counteract the force of gravity, so the opposite will happen. In the Big Crunch, the cosmic inflation would eventually reverse: galaxies would get closer and closer together, colliding with each other and collapsing under their own gravity. Every chunk of matter in the universe would fall in on itself till it reaches a point of singularity — an infinite dense speck just as it was in the beginning. From what we know about dark energy, this scenario is less likely to happen.
#3. The Big Rip
In the Big Freeze, dark energy is more or less constant; in the Big Crunch, it weakens; but in the Big Rip it gets stronger. Just as it’s name suggests, dark energy gets stronger and stronger over time, making everything in the universe “rip off” each other. In this scenario, not only would galaxies move away from each other, but they would begin to expand from within. Galaxies, stars, and planets would rip apart from each other, and eventually, dark energy would become so powerful that it would tear apart molecules and atoms.
As theoretical astrophysicist Katie Mack said at the NECSS conference:
“If the Big Rip is coming, it’s not coming for a very long time, we have at least 120 billion years before we have to worry about this. So you can rest easy — it’ll be a while.”
#4. Vacuum Decay
The aforementioned scenarios could take eons, but vacuum decay could happen at any moment. This is based on the nature of some assumption known as Higgs field — which permeates our universe and varies in strength based on it’s potential. Think of this as water in a waterslide: the higher the slide, the more energy the water has to slide, and the lower the slide (say the bottom of the pool), the less energy there is, and that would be our vacuum state.
Here’s the catch: there are two possibilities here, too. There could be a true vacuum, where the energy of the Higgs field really is the lowest state it can go. And there could also be a false vacuum, where there could be another lower-energy state we have no idea what. Let’s say we’re chilling out at the bottom of the slide — the pool happens to have a giant bathtub plug, and pulling it can make all of the water rush into an even lower state. Sounds familiar?
“That would be bad,” Mack says, “because the true vacuum has different constants of nature than the false vacuum. Constants of nature are things like the charge of the electron or the mass of the particles or even the strength of gravity sometimes. So if you take the molecules that you’re made of and put them into a true vacuum state, those molecules don’t hold together anymore. Total destruction.”
What if an event with enough energy happens at any time that could pull out our hypothetical bathtub plug, then the rest is history. What more? This could be as a result of quantum entanglement: the ability of particles tunneling through a barrier — whether from one end of a wall to another or from one point in space and time to another moment. Who knows? Quantum fluctuations could cause this, too. All it takes is one lone particle flitting off to somewhere it shouldn’t, and reality would cease to exist. Sweet dreams!
How do you think the universe would eventually end?
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Written by: Nana Kwadwo, Sun, Aug 11, 2019.