We live in a violent universe full of black holes devouring titanic amounts of matter
and galaxies colliding, sparking off massive amounts of star formation all the way to entire
planets crashing into each other.
But there is one cataclysm that could be possible that would utterly dwarf even the most violent
events in the universe.
It’s if the universe destroys itself entirely or something else does.
The idea that this could happen is rooted in some very mundane, everyday physics.
When an atom is excited and in an elevated energy level, it can decay to a lower energy
level, emitting a photon in the process.
This may be true of the universe as well in that the quantum vacuum could also have a
lower energy state.
This involves dark energy having a quantum origin, which is currently the general consensus.
This may mean that the universe itself is excited, and there may be other levels and
it may not be at the lowest one and thus would not be completely stable.
That means that at any time it could decay to a lower state and that would be beyond
catastrophic on the biggest scale there is.
It would be the apocalypse of the universe.
It would start at some point in the universe and then radiate out at almost the speed of
light traveling in all directions.
The titanic amounts of energy created by the process would form a shockwave utterly destroying
anything and everything in its path with absolutely no warning.
No one would see the shockwave coming until it reached them and instantly destroyed them
leaving behind an altered universe with altered laws of physics such that even matter itself
may no longer be able to exist.
This process of destruction would take an enormous amount of time to accomplish as the
universe is unbelievably large and possibly even infinite, so it may even be that this
has already happened but could outside the observable universe.
An infinite universe cannot be destroyed by a finite expanding process.
Just parts of it can, so if the universe is infinite it may resemble a huge piece of swiss
cheese.
If it’s not infinite, it may be a self consuming piece of cheese with ever growing holes gobbling
it all up and we are blissfully unaware that the universe is destroying itself as we speak.
And there is a variant of this scenario first proposed by physicist Edward Witten.
In this scenario the expanding hole doesn’t even contain a lower energy quantum vacuum,
but absolutely nothing.
The expanding void of nothing would consume everything until there was nothing left to
consume and what’s left is a completely empty universe.
Perhaps this is how cosmology works, a universe is born, consumes itself, and then the blackness
just awaits a new big bang going off, in a situation resembling the Conformal Cyclic
Cosmology of Roger Penrose.
So do we see bubbles of nothing in the universe?
Well yes, but it’s not likely to be due to this issue.
It’s actually worse.
This involves the cold spot in the cosmic microwave background radiation.
This cold spot should not be.
The CMB is very uniform, ridiculously so, with only very tiny temperature variations
defining it.
These variations are highly important, they are what allowed the universe to clump together
after big band and form up.
Had the tiny variations not been present, the universe would have been perfectly homogenous
and unable to clump with all matter equally distant and unable to clump together to form
hydrogen nebulas and eventually stars.
But the cold spot is something on the order of six times colder than any other of the
many temperature anomalies in the CMB.
There haven’t been very many good explanations for the presence of the cold spot, so the
theories got increasingly speculative, but some do actually seem testable.
One is that our universe flat out collided with another universe entirely.
This has some spooky implications, though no observational evidence of the predicted
gravitational waves and polarization in the CMB that should result from that have been
found.
And if that possibility of colliding universe can happen, then the idea of the universe
itself being eaten by another larger universe comes on the table.
What would happen if that occurred?
Would everything in the universe suddenly vanish?
What if the laws of physics of that universe were different and everything suddenly changed?
It’s a complete unknown whether events outside of our universe could affect us inside it.
I’ve done past videos on a discrepancy called the axis of evil, where the overall temperature
of the CMB is different north and south, and how this very strange feature somehow lines
up with the plane of the solar system.
But one thing that could cause it possibly is if the universe were being compressed by
something and just so happens to line up with the plane of the solar system entirely by
chance.
And there are the ideas of other universes existing on top of us, hovering just above
us imperceptibly occupying the same space.
But ultimately it’s not known what the CMB hole is.
Another option is that it is a kind of hole in the universe looking out on the multiverse.
We would be seeing what was before the big bang, potentially opening up a way to probe
the multiverse itself and see what was here before the universe existed.
But it’s also possible that we are the giant monster universe gobbling up smaller universes.
Here our universe is the blundering giant zombie wandering around destroying other smaller
universes, for all we know inhabited by poor schmoes going about their business only to
be eaten by the human universe and cease to exist.
All while we happily drink coffee over a nice donut not giving a single thought to what
might be happening out there in the horrific multiverse.
But this all leads to an even more disturbing question.
Is the universe even really here?
In quantum mechanics particles are known to exist in superpositions, many different quantum
states at once.
This is the basis for Erwin Schrodinger’s famous cat.
It is both dead and alive at the same time until you open the box and collapse its superposition.
When you scale that up, the universe itself should also have a superposition.
But it appears to be collapsed, we do not seem to exist in a quantum superposition state.
So why is that?
No one knows.
The situation basically has been that it must get collapsed somewhere along the way and
that’s that, but there has to be a reason and the current favorite is called decoherence.
This in a nutshell says that information leaks out and that individual particles can be isolated
enough to pull it off but as a whole everything decoheres and cats do not exist in uncollapsed
superpositions.
That works well for cats, but not universes because for the universe’s superposition
to collapse in this manner then information must be leaking out of it, but into what?
If there isn’t a multiverse or something out there for that to happen, the universe
gets weird.
It means on its face that its superposition must be collapsed by observers, in other words
us, or by some unknown process.
The universe is not there when we are not looking at it and if we are alone and life
on earth ended, maybe the universe would cease to exist.
This makes no sense, obviously the universe was here before we were so that led physicists
to look at different possibilities.
One of these involves the many worlds interpretation of quantum mechanics.
This is where the universe splits into literally many worlds, each almost identical to each
other.
You would have a counterpart in another universe that had a different breakfast than you had,
but would be otherwise identical, and these universes would be splitting off constantly
with slightly different occurrences.
This conveniently gives a place for the universe to leak information to, thus collapsing its
superposition.
But that leaves one final enormous question.
What exactly is the universe?
The conventional answer to this is that it’s everything that was, is or ever will be.
And that includes us, we’re every bit as much a part of the universe as an asteroid,
and that also includes our consciousness.
But could it be more mundane than that, if you want to call this mundane.
There is one idea out there that the universe shares some characteristics with black holes.
Is it possible that we actually do live inside a black hole?
And while that’s on one hand somewhat of a disturbing notion, on the other hand we
know that black holes are very stable things and take absolutely enormous amounts of time
to evaporate.
They do indeed devour matter, but they don’t devour themselves.
In that case, happily, the universe won’t be self-destructing any time soon.