You find yourself tumbling through space.
Moments before you were just out on a routine space walk examining some minor cosmetic damage
on your ship when suddenly, you started feeling strange.
You felt a lurching in your stomach as your body started accelerating, and now you find
yourself hurtling helplessly through deep space in the direction of the universe’s
most powerful, most mysterious killer: A black hole.
You need to understand black holes.
And fast!
Here are fifty insane facts that may help…
Fact One!
A black hole is a point in space that has such a strong gravitational pull that nothing
can escape it.
Not even light.
Our sense of sight relies heavily on seeing the light either emitted or reflected from
the surface of objects.
A black hole doesn’t let that happen.
Fact Two!
The border at which light can no longer escape is known as the event horizon.
Since light is the fastest thing in the universe and has the best chance of getting away, it’s
safe to say that anything else passing the event horizon will also end up tumbling in.
Fact Three!
Right now, you’re hurtling towards the event horizon, going faster and faster.
What will happen if you go past it?
Well, the process is called ‘speghettification’, and yes, that is its real name.
The gravitational force affecting your feet will be stronger than it is at your head,
meaning your toes will be stretched away from the rest of your body.
At the same time, they’ll be compressed together, forced into a tinier and tinier
space, meaning you will be strung and stretched into a piece of human spaghetti for the black
hole to slurp up.
Delicious.
Fact Four!
If you look down, all you will see is blackness as no light is rising up towards you from
the black hole, but if you manage to crane your head just enough to look up behind you
on your way in, you will be able to see where you have come from.
That’s because the light behind you is traveling in the same direction you are and at a greater
speed, so the photons will still hit your eyes.
Fact Five!
Soon, you’ll pass the photon sphere, and things will start to look weird.
Your window of the universe curves up and away from you, steadily shrinking smaller
and smaller, giving you one last glimpse of your crewmates waving at you from the escaping
ship.
Fact Six!
But that fate actually depends on the kind of black hole you’re in.
The spaghettification happens if you are falling into a stellar black hole.
A supermassive black hole will be much stronger but will treat you slightly better.
That’s because the stretching tidal force is less here.
But bad luck, you’re still not making it out… or could you?
To understand your chances at escape, we need to first understand black holes in a bit more
detail.
Fact Seven!
Since they’re black, and space is also black, it took scientists a long time to realize
they were even there.
As far back as 1784, an astronomer by the name of John Michell theorized that such a
thing could exist.
He called them Dark Stars and thought that they were normal functioning suns like our
own.
His theory was that they were so big and heavy (500x the diameter of our sun!) that the light
particles would fly out away from them, gradually slow down, and be pulled straight back in
by the force of gravity.
Of course, his theory doesn’t hold water today as we know that the speed of light is
constant, you can’t simply slow it down, and that light isn’t a particle.
Or is it?
More on that later.
For now, let’s focus on the black holes themselves!
Fact Eight!
Where do Black Holes come from?
Well, let’s start with a cloud of dust and gas, or a nebula.
Loose matter floats around in space.
Each particle has a tiny gravitational pull, and so they eventually start clumping together.
The more it all clumps together, the more mass it has.
The more mass it has, the stronger its gravitational pull.
Meaning more dust and gas.
In the middle of things, the particles start colliding more and more.
Each collision produces some heat.
Keep this going long enough, and soon, you’re cooking with a Main Sequence Star.
The outward pressure of the nuclear fusion reactions in the middle balances out the gravitational
forces pulling everything towards its core, and so this star is happy and healthy for
billions of years.
Our own Sun is square in the middle of this era.
But all good things come to an end eventually.
If the star is big enough then eventually it will no longer have enough energy to balance
out the forces of its own gravity.
It will have one last giant explosion called a ‘supernova’ and leave behind an incredibly
dense core that collapses in on itself and forms a black hole.
Fact Nine!
The core crushes itself smaller and smaller and smaller infinitely.
The point of a black hole is infinitely dense and infinitely small.
The core that was once as heavy as 10 of our suns crushes itself to be smaller than an
atom.
Smaller than a nucleus.
Smaller than a proton.
Smaller than a quark.
All the way down to a Planck Length.
But at that point, the universe hits its size limit.
Quantum physics and our models of reality simply cannot compute anything beyond that
point as the wheels all fall off the carriage.
We cannot ever know with any certainty what happens beyond that small of a point since
the concept of ‘happens’ no longer even applies.
Fact Ten!
If you want to understand just how small the Planck Length really is, picture a speck of
dust by your window.
Compare that speck of dust to the size of the Earth.
It’s tiny!
But on a log scale, that speck of dust is the halfway point between the mass of the
Earth and the mass of an atom.
Fact Eleven!
But the size of an atom is 100,000 times bigger than its nucleus.
So, if the atom was the size of the biggest NFL stadium in the US, the nucleus would be
a marble in the middle of the field.
So that’s almost the size of a Planck Length, right?
Fact Twelve!
Nope!
You need to go a quadrillion times smaller than that and then do the football stadium
and marble trick again.
If the whole Earth was the size of an atom, a Planck Length would be smaller than a proton
in the core of the Earth.
Fact Thirteen!
So, what’s at the other end of the scale?
If the singularity at the core of a black hole is compacting it down to the be the smallest
thing, what’s the biggest thing?
You’ve guessed it.
Black holes.
Fact Fourteen!
Black holes are measured in Solar Masses, in other words, that’s the mass of our very
own sun!
This mass is 2×10^30 kg.
That’s 2 with 30 zeros after it or two nonillion kg.
Fact Fifteen!
A black hole the size of Japan would weigh about 140 solar masses.
That’s 140 of our suns squashed to 0.001 percent of their usual size.
Fact Sixteen!
We have a gap in our black hole size comparison chart.
A BIG gap.
Scientists have observed plenty of black holes around this size range up to about 150 solar
masses.
The next ones up in size are millions of solar masses.
Why aren’t there any in between these two?
Find out, and you could win a Nobel Prize!
Fact Seventeen!
What’s worse than one black hole?
Two!
Since they are so massive, they tend to attract other equally massive bodies towards themselves,
including other black holes.
That’s right, black holes can join together to be even bigger and badder.
Fact Eighteen!
When two black holes join together, they release the most energy of any known phenomena in
the universe, besides the big bang!
Two massive bodies, weighing the equivalent of a couple of million stars each, swirling
around and around, getting close to each other and sending incredibly powerful gravitational
waves rippling through space in their wake.
Fact Nineteen!
We all know that black holes can crush you, but do you think you could ever have a crush
on a black hole?
The iconic meme character Black Hole-chan is based on the personification of a blank
hole in the form of an anime girl - because certain parts of the internet are just like
that.
Specifically, she’s based on the Black Hole in the center of the Messier 87 Galaxy, which
became a generally huge meme in 2019 when a photo of it was successfully captured by
NASA’s Event Horizon telescope and released to the public.
Fact Twenty!
Black Holes have a bit of a bad rep for sucking in stars and galaxies, but did you know they
can have an equally important role in creating them?
According to a 2018 study, fragments loosed from black holes can sometimes create entirely
new stars, and Supermassive Black Holes sometimes play a part in determining how many stars
a new galaxy has by influencing the process of star formation.
According to the study, the smaller the black hole in the center of a galaxy, the sooner
the process of star formation turns off, leading to smaller galaxies in turn.
Fact Twenty-One!
Sagittarius A* is the black hole at the center of our galaxy The Milky Way is much, much
smaller than that in comparison.
Its radius is only 17x our sun.
It’s tiny, and so our galaxy is fairly stable.
Fact Twenty-Two!
So, what’s the biggest black hole ever?
Well, the biggest we’ve found so far is Phoenix A*.
You can find it at the center of the Phoenix Cluster, and don’t worry, it’s about 5.8
billion lightyears away.
You won’t be falling into it anytime soon.
Fact Twenty-Three!
The previous record holder, TON-618, was pretty terrifying already, but Phoenix A* is 1.5x
bigger than even that.
Fact Twenty-Four!
Here, the numbers get even more ridiculous.
It weighs the same as 100 billion suns.
Fact Twenty-Five!
You could fit the entire solar system into its diameter, 50 times over.
Fact Twenty-Six!
A photon of light that falls inside its event horizon would take well over a week to reach
the singularity at its center.
Fact Twenty-Seven!
Scientists have had to come up with a new category for black holes to accommodate such
gargantuan celestial bodies.
Ultramassive black holes.
Fact Twenty-Eight!
But now Phoenix A* has pushed for an even bigger category: stupendously large black
holes.
Or SLABs.
Who says physics can’t be fun?
Fact Twenty-Nine!
But Phoenix A* is probably even bigger than we think.
Since it is 5.8 billion lightyears away, we are looking at an old version of it, since
the light has taken 5.8 billion years to reach us.
That means it’s already had an extra 5.8 billion years to grow, and right now will
be a good deal larger.
Who knows how big the biggest black hole in the universe is right now?
The best we can do is point our telescopes at the stars and look.
Fact Thirty!
This brings us to another question: how do you find a black hole?
If they absorb all light and are in the darkness of space, how do you see one?
Well, you find a black hole by looking at its effects on gravity.
Because they are so massive, they exert immense amounts of pull on the matter around them.
Things start to act weirdly when they are next to a black hole.
Fact Thirty-One!
We often find them at the center of galaxies, and so you would assume they are holding everything
together, right?
The sun in our solar system is so heavy that it holds everything in orbit around it.
In reality, most galaxies are instead held together by the forces of dark energy!
Fact Thirty-Two!
One example of things getting weird is the Cygnus A black hole, which is 14 million suns
in mass.
It’s surrounded by a spinning disk of matter in a fast accelerating orbit that is steadily
being devoured beyond its event horizon.
Matter is spinning around it so quickly, in fact, that there are funnels of plasma shooting
out of the top and bottom that are traveling close to the speed of light!
Fact Thirty-Three!
While Black Holes are isolated interstellar events, there is a possibility that they could
have created similar qualities across multiple instances.
Deep radio imaging from astronomers in South Africa has revealed that many of the supermassive
black holes in a particular region of space have radio jets that align the same way.
Whether due to enormous electromagnetic fields or other primordial intergalactic forces,
it seems as though the condition of the universe at the dawn of time played a role in this
shared alignment.
Either that or the black holes are communicating with each other and deciding to match, which,
while fun to imagine, isn’t scientifically possible.
Fact Thirty-Four!
Theoretically, if it was squeezed down to a size of only 3.7 miles or 6 kilometers across,
our sun’s mass would be compressed enough to become a black hole.
In theory, this is actually true for any object - Including your body!
Thankfully, a means of causing that degree of compression isn’t exactly within our
grasp, so don’t expect it to happen any time soon.
Fact Thirty-Five!
Some of the earliest black holes are believed to be appropriately named Primordial Black
Holes!
The general consensus among scientists is that these black holes formed from the condensation
of raw materials in the aftermath of the Big Bang, and most of these were far tinier than
the majority of black holes currently at large in our universe today.
Fact Thirty-Six!
There’s been a lot of discussion about the masses of various black holes in this video.
It wouldn’t be unreasonable to wonder: How do scientists actually measure the mass of
these things?
The answer is simple in theory and incredibly complex in practice: They do it by studying
the behavior of surrounding celestial bodies with incredibly powerful telescopes.
Fact Thirty-Seven!
We’ll all end up in black holes eventually.
One day, the universe will be made up almost entirely of black holes.
Unlike a star, there is no big explosion at the end of a black hole.
They keep on growing larger and larger as long as there is more mass to absorb.
One theory about the way our universe could end is the big crunch.
The Big Bang happened, everything expanded outwards, but eventually, gravity would pull
it all back together again in one big crunch, theoretically triggering another Big Bang
event.
The current model is much more bleak.
The expansion of our universe isn’t slowing down like it should be about now.
It’s accelerating.
There’s another force pushing it to get wider: Dark Energy.
Fact Thirty-Eight!
Dark energy is now believed to make up 69% of the universe’s mass, and that dark energy
is causing it to continue to expand.
Fact Thirty-Nine!
Regular matter, the stuff we’re built from and everything we observe around us, makes
up only 5% of the cosmos.
Fact Forty!
In just a couple trillion years, the universe will have expanded so much that we won’t
be able to see our neighboring galaxies anymore.
Stars will stop forming, and black holes will grow larger and larger as they swallow up
all that’s around them.
Fact Forty-One!
Then we’re into the Big Freeze.
Black holes will dominate the universe, having absorbed virtually all of the matter and thermal
energy around.
The average temperature of the universe will sit just above absolute zero.
Fact Forty-Two!
So that’s it, then.
Black holes will live forever, and there will be nothing left.
Well, not quite.
You see, a black hole can actually die.
Fact Forty-Three!
In 1971, Stephen Hawking had an idea.
He had spent years studying quantum mechanics.
He was fascinated by the constant links between the smallest things in the universe and the
largest.
He believed that you simply couldn’t understand black holes without quantum physics and vice
versa; the two are inseparably linked.
Hawking made a huge breakthrough that took decades to be proven, changing our model of
how a black hole dies.
Do you remember when we told you that nothing can escape a black hole?
Well, that isn’t quite true.
Quantum mechanics has revealed that in the depths of space, all the time, little particles
flit in and out of existence.
These are called virtual particles.
They come in pairs: matter and antimatter.
Since they have opposite charges, they almost always immediately crash into one another,
canceling each other out.
But next to a black hole, the gravity is so strong that they get separated.
One flies into the core of the black hole, and the other flies off into space.
Fact Forty-Four!
Over time, black holes cool down.
The particle from that pair that falls into the black hole has negative energy, so it
reduces its temperature by a tiny, tiny, tiny amount.
The one that gets away has managed to escape the clutches of a black hole with a tiny,
tiny, tiny amount of positive energy.
This is called Hawking Radiation.
So, just like a glass of water on a table eventually evaporates, so too does a black
hole.
Of course, this can only happen once they’ve fed on all of the abundant matter around them
and are left alone in a cold, dead universe.
So there’s your escape plan!
It’s simple.
All you need to do is just spontaneously generate an antimatter version of yourself at the exact
right moment, and negative-you can fall to their death while positive-you gets away scot-free.
Sadly no.
You won’t be escaping like that.
So unless you have a pretty powerful rocket strapped to your back with near-infinite fuel,
it’s probably too late.
Fact Forty-Five!
But you’re in luck!
There’s no spaghettification happening to you here since you’re falling into a supermassive
black hole, and you’re not being funneled into quite as small of a space just yet.
As your crew watches you cross the event horizon, they see something weird.
Your body, moving in super slow motion, suddenly pauses as you cross it.
A still frame of you hangs in their vision slowly fading away.
No more light is able to reflect off your body, so the last instant where it could sticks
around for a few moments as it slowly fades away.
Like a ghostly afterimage.
Fact Forty-Six!
Space and time inside the black hole stop behaving as they should.
Any direction that you try to move takes you close to the center, even if it seems like
the direction you had just come from.
Fact Forty-Seven!
You’re well on your way to becoming part of the singularity.
Since it crushes everything down so small, there is no way of knowing that it was ever
you who went into it.
All information that we could ever hope to gather from a singularity is crushed out of
existence.
This means that if you ‘switched off’ every black hole in the universe and compared
the singularities side by side, you’d have no way of knowing which was which.
From the biggest black hole to the smallest, they’d all be identical.
Fact Forty-Eight!
Over time, the Hawking Radiation will shrink the black hole further and further until,
eventually, the singularity at the center will vanish from existence, giving off a burst
of energy on its way out and leaving nothing.
Fact Forty-Nine!
Except, of course, we are only humans, and our brains are absolutely tiny relative to
the scale of the universe.
Our ability to understand these concepts is severely limited especially since we can’t
exactly head over to one to run experiments.
It’s virtually all theoretical, and one of the big limitations we’ve put on our
models is that we almost always calculate for black holes that aren’t spinning.
Our models of singularities all hinge around a single point of infinite mass.
But with black holes spinning at the speeds they do, that just wouldn’t be accurate,
the core would be spinning as well, forming a little ring or ‘ringularity’.
Fact Fifty!
If we can barely understand black holes that are stationary, we are a long way off from
figuring out ringularity black holes.
And here lies your one last bit of hope.
Under Einstein’s laws of general relativity, anything passing through a ringularity is
actually passing through a wormhole and will pop out of a white hole.
This is the opposite of a black hole.
Nothing can enter it, and everything leaves it traveling even faster than the speed of
light!
So, do these exist?
They can’t, according to thermodynamics.
But according to general relativity, they must.
So, where do you end up once you’ve fallen into the core of a black hole?
Do you now fly out of another black hole but now traveling backwards through time?
Do you appear in another dimension altogether?
Does this mark the big bang bang of another pocket universe inside our own?
Your guess is as good as ours.
It’s just a shame you won’t be there to see it, given you’ll be very much dead by
the time you get there.
It was nice knowing you, good luck!