What Happens When a white hole and a black hole collide?
Collisions are as frequent as sunrises in the universe,
but what’s the most interesting one we can ever imagine?
Today, let’s talk about what happens when a white hole collides with a black hole!
Okay, to start off, let’s take a short trip down memory lane.
I promise this is going to make sense.
Back when you’re in school, did you ever have armchairs? I did.
I remember a particular time when I was seated beside someone who’s writing hand
is opposite to mine -- I’m right handed and he’s left handed. So naturally,
we would compete for elbow space in our respective desks! We both need to write stuff,
so it’s inevitable that at some point, these body parts ought to collide. I couldn’t tell
you how much I would love to have an extra wide gap between us just keep that from happening.
Now, if we were to have an entire universe as our elbow room, we would never ever have to
be annoyed ever again, right? Well, the universe doesn’t really work that way.
It’s easy to think that there wouldn’t
ever be any collision that will happen having a vast amount of space,
but we all already know that that isn’t the case. It’s elbows hitting one another all the time.
There are definitely all kinds of collisions happening all over the universe.
Planets colliding with stars, Stars colliding with other stars,
black holes colliding with stars, black holes crashing onto one another,
and the list goes on and on. All of these are possible thanks to a little thing we call gravity.
However, I bet there’s nothing more interesting among all of these than
the one we’re discussing today: what happens when a white hole collides with a black hole?
Sounds exciting? Then hold on to your pants, because it’s about to get wilder!
So, let’s start with a bit of recap about white holes and black holes.
Through Einstein’s theory of general relativity, the paradigm of having time as the ultimate
standard unit of everything has changed completely. Now, we have an understanding that
time is actually inseparable from space, and the very plane of the universe is actually spacetime.
And in spacetime, massive objects cause a distortion which we laymen call gravity.
Let’s not talk about the pure math involved but in a more specific but simplified sense,
Einstein’s field equations consequently predicts the existence of a black hole.
And since its polar opposite, the white holes, are just basically black holes going
backwards in time, then theoretically, they should be able to exist as well.
Let me put it down in a crazy analogy. Do you know the world famous horror character Slender Man?
If that thing exists, then it implies that a Hefty Man also exists with opposite characteristics.
Maybe he’s friendly, and helps you with your day-to-day life. Who knows?
I know that’s very watered down, but basically that’s
how theoretically white holes came into concept.
Moving on, a black hole is a region in space
that’s so dense that spacetime is effectively distorted heavily by it.
The gravity of a black hole is the strongest ever known that nothing can ever escape it, not even
light. Think about that: the fastest thing in the universe itself is powerless against a black hole!
Okay, now, imagine that you make a black hole run in reverse time,
then you get a white hole. If a black hole is a region of strong gravitational force where
nothing can ever escape, a white hole, on the other hand
is a region in space where nothing can ever enter. Things can only exit out of it.
Oh, and by the way, if white holes are something that’s totally interesting to you,
why don’t you go ahead and check our other video about it? You’ll
be more amazed by how outrageously cool they are.
Both of these two titans have their own unique event horizons and singularities as well.
Do you remember what an event horizon is for a black hole?
It’s okay if you don’t. That’s what this channel is here for.
For a black hole, the event horizon is the region where the force of gravity is so strong,
that once anything crosses this, there won’t be any chance of running away.
Any matter that makes it this close will accelerate in a speed
even faster than the speed of light until they all get drained into the singularity.
Okay, before we carry on, I can hear a lot of you reacting to that last line.
I know you’re saying “are you sure about that? Nothing can go faster than the speed of light!”
And I will reply with a “that’s right!”, but you are forgetting a few things.
Light propagates through spacetime itself, so as long as we observe an effectively, quote-unquote,
non-accelerating spacetime, then, yes, the speed of light is constant. But keep in mind
that black holes are outrageously powerful that it effectively distorts spacetime, so therefore,
anything getting sucked into it is effectively moving faster than the speed of light.
Let’s say there’s a waterfall right in front of you, and you have the fastest remote-controlled
toy boat in the world. You can set that vehicle into top speed, but you can never ever make it
climb to the top of the waterfall, right? That’s kinda how spacetime and light works.
Now, let’s go to black holes’ completely polar opposite twin. How about we do it with
some sort of mental exercise? It’s nice to get a little bit of brain workout every now and then.
Remember earlier that we established that white holes are effectively time-reversed black holes?
Okay, so if that’s the case, and you know that in a black hole’s event horizon,
nothing can ever escape, how do you think white holes’ event horizon should look like?
Do you think you know the answer? Why don’t
you leave a comment below and let’s see who got it right?
Okay, no more delays. For a white hole, the event horizon is the region around it
wherein when anything exits it, it wouldn’t be able to go back. Basically, matter and
light -- and of course, spacetime, spews out from a white hole’s singularity and expands from there.
Before we go on any further, I’d like to know if you liked the show so far! If you do,
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So now that all of these introductions are out of the way,
let’s dig into what will happen when a white hole collides with a black hole!
I know that we have some serious astrophysics folks in the audience that’s going to say
that it’s practically impossible for a white hole
and a black hole to collide due to their own characteristics,
but, for the sake of curiosity, let’s assume that this scenario is completely possible.
Now, for us to visualize what would happen we need to go to the kitchen.
No, seriously. We need to go to the kitchen. We need to perform some kind of mental experiment.
And it has to be mental, since we can’t be physically together to perform this experiment.
You know. Some places still has lockdowns in effect.
And I know you think this is foolish, but this is literally how scientists simulate
and study how a white hole would theoretically work, if we ever get to finding and studying one.
Okay, so let’s say you’re in the kitchen, you walk to the sink, and you open the faucet. The
stream of water hits the surface of the bottom of the sink, and what do you see?
The impact of the water hitting the surface forms some circle of shallow water,
and an outer wall of flowing water, right? I hope that’s not too hard to visualize.
Now, let’s say you have a dye on a vial, and you placed a drop on the outer wall.
You’ll see that no matter how aggressive you place your drop of dye,
it can never reach the inner circle. This is effectively how a white hole operates in itself.
Okay, so if that’s the typical, simple simulation of a white hole,
then how do we simulate a black hole? Got any ideas?
Well, you won’t have to go far. You can simulate a black hole at the very
same place where you watched how a white hole works. The drain of the sink can do all that!
So, since we can simulate both how a black hole and a white hole works
by just looking at how water flows in a sink, I hope it’s pretty obvious that finding out
what happens in a black hole white hole collision can also be observed here.
If the water from the faucet simulates a white hole, and the drain on the sink,
a black hole, then a collision can be visualized by directing the flow of the water into the drain.
By doing so, you can see that there wouldn’t be any pool of water forming around the drain.
In a more complicated terminology, in a black hole white hole collision,
the most likely conclusion is that the black hole swallows the white hole in its entirety.
I know, I know. It’s a bit anticlimactic to know that you can practically demonstrate
one of the most devastating collisions in the universe to a five year old by just
merely doing dishes. No fancy lab equipment, no expensive laboratory equipment...all
you need is flowing water, and a drainage where the water flows.
So, what happened there? Didn’t we establish that white holes and black holes
are equally devastating in terms of their destructive power?
Well, one thing to take into consideration is that white holes are extremely unstable. And that’s
not quite surprising! If you’re an object who constantly hates to obey the laws of physics in
this universe, you’re ought to be highly unstable. I mean, a white hole practically spews matter out
of “nothing”. That shouldn’t hold up so much according to the second law of thermodynamics.
Also, there is a theory that white holes evolve into black holes over time.
If we follow this logic, then what most likely would happen is that upon coming into contact,
the matter, light and radiation from the white hole gets instantly sucked into the black hole,
making it bigger and bigger as time goes. Then, when the white hole finally
collapses into a black hole, we’re going to be left with an extremely obese black hole.
Of course, this is a very generalized case.
We are not sure yet what happens when either the white hole or black hole is larger,
or if the same thing happens when the white hole and the black hole has the same mass.
Well, the good news is, we won’t have to worry for now. Nobody has ever seen a white hole so far.
A lot of what we have right now is pure theory,
and we can never really know for sure until we can make observations.
Okay, enough about me talking. I’d like to know your thoughts, guys. What do you think a white
hole and a black hole collision would look like, when we finally see one? Do you think it will be
similar to a supernova, exhibiting a beautiful explosion of energy? Do you think it would be
less extravagant like just popping out of the spacetime plane? Let me know your ideas by leaving
something in the comments section down below! I promise I’d take the time to read what you write.
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