The Weird Physics Surrounding Black Holes That Will Make You Question Your Existence

black holes are one of the most

mindboggling aspects of

space for a start they aren't actually

objects they are the result of the

extreme warping of SpaceTime and because

of this warping some really weird stuff

starts to go on around them that will

change your perspective of the way the

universe operates around

you some of it is so strange that

perhaps you won't believe it was true

were it not for the solid math that back

up their existence and properties and

the increasing evidence that the math is

correct through observations in our own

Universe I'm Alex molan and you're

watching asram and in this video we will

be exploring the unexplorable join me on

this journey as we attempt to understand

the Weird Science of how a black hole

forms what goes on around them and

explore what might actually allow for an

escape from the most inescapable prisons

in existence I hope by the end of this

video video to have earned your like and

subscription black holes come in a

variety of sizes the smallest observed

black hole is around 3.8 solar

masses on the other side of the scale we

find black holes that have been in

existence since almost the start of the

universe black holes weighing billions

of solar masses these bths are not only

massive but also so huge they would

easily fit in the entire solar system

within the diameter of their Event

Horizon black holes being created today

are the final stage in the life cycles

of particularly massive stars when such

a star is born it is essentially

balancing under the weight of two forces

the first is gravity pushing its mass

towards its Center down in the depths of

the star hydrogen atoms are crushed

against other hydrogen atoms with such

force that they combine to form a denser

element helium this new atomic structure

actually needs less energy than it did

when it was two individual separate

hydrogen atoms so the extra energy left

over gets released this released energy

is the second force it radiates back out

from the center of the Star as heat and

light counteracting the force of gravity

pushing in in this state the star will

remain relatively stable until such a

time as the reaction begins to stop as

it runs out of its hydrogen

fuel if the star is massive enough once

the hydrogen begins to run low the star

will combine the newly formed helium

into even denser materials like carbon

neon and eventually oxygen and silicon

but then it begins fusing iron the issue

with iron is that it doesn't save any

energy in its new form so has no spare

energy to release it just sits in the

core of the star growing larger with no

energy pushing Back Against Gravity very

quickly the scale

tips the energy of this collapse is

astounding but the force is dependent on

the original mass of the star like a

hammer striking on an anvil the mass of

the star rushes down to meet the core

with such force that the rebound of that

blow is what we call a

supernova matter and energy are blasted

out Across the Universe from the

crackback in one of the largest

explosions possible which produces

elements even heavier than iron all the

way up to

uranium and what is left with the star

well it depends if the mass of the star

and thus the force of the blow was too

low what remains is a neutron star a

small ball of matter at most around 25

km in diameter and yet so densely packed

with mass that it equals a million

Earths but if the mass and thus force

was big enough physics as we know it

breaks down and we are left with a black

hole when you see an image of a black

hole the black sphere you are looking at

is not actually the black hole itself

scientists theorize a black hole's true

form is probably even smaller and denser

than a neutron star in fact it is likely

infinitely small and infinitely dense a

singularity emitting forces that warp

time and space itself however we don't

know and the reason we don't know know

is because of something called The Event

Horizon all objects with mass exert

gravity we've known this since the days

of Newton however when Einstein came

along in 1915 with his theory of general

relativity a contemporary of his called

KL schwat Shield reasoned from it that

there could exist objects that were so

massive they could create enough gravity

that light itself could not escape and

if even massless light photons couldn't

get out nothing could

when you look at a picture of a black

hole you are not seeing the black hole

itself you are seeing the Event Horizon

around it the demarcation line where

gravity has become so powerful that

light can no longer leave there is

nothing but

Darkness now its effect on space is one

thing but black holes also impact

another aspect of the universe time

itself you see according to Einstein

space and time are inseparably connected

and Mass warps

SpaceTime with the singularity's

infinite point of mass it stretches

SpaceTime so much that the event horizon

also marks the point where time

stops within the Event Horizon space and

time basically cease to exist a place

where there is no where or when this

produces an interesting phenomenon to an

outside Observer watching matter fall

into a black hole from their perspective

as matter approach approaches the black

hole it will slow down until just before

the event horizon where it will stop

altogether you won't ever see it cross

the Event Horizon there will be no

satisfying absorption instead the matter

will gradually dim until you can't see

it

anymore when first theorized astronomers

and physicists were uncertain if black

holes were actually real it was only 40

years later that the first evidence of a

black hole was

recorded in 1964 using newly developed

x-ray satellites scientists noticed an

object in the constellation signus that

seemed to be emitting a large amount of

x-rays strangely enough though

scientists could not see the object

itself it surprised them because if it

was a star it ought to emit visible

light as well as x-ray radiation

scientists call this object signis

X1 in 1970 as telescopes Advanced they

noticed that whatever signal X1 was it

had formed a binary orbit with a star in

its system and this helped scientists

calculate its mass they discovered that

this invisible object was 15 times more

massive than the sun as the densest

neutron star had an upper limit of three

times the mass of the Sun scientists

realized that this was most likely the

first ever discovered black hole since

then we have discovered many black holes

massive ones seem to exist at the center

of galaxies and we've even man manag to

take photos of some dark blots against

the swirling ring of matter that

surround them and fall into them they're

accretion

disc this is how black holes can still

be detected through x-rays while black

holes can't emit visible electromagnetic

radiation themselves the x-rays that

come from them actually originate from

the accretion discs where infalling

matter gets heated to millions of De C

through intense

friction black holes with no falling

matter are basically invisible with no

bright accretion disc to

spot exploring black holes is still a

developing field in physics and there is

still much to learn from what we have

learned so far you may wonder if a black

hole could ever stop being a black hole

or will it grow Forever Until there is

no matter or radiation left in the

universe it would seem

[Music]

so however in 1974 in his paper entitled

black hole explosions physicist Steven

Hawking postulated that there was

actually a way that energy and thus Mass

could leave a black hole but to

understand why we have to get into some

extremely weird Theory we need to

examine some principles of quantum

mechanics but first let me ask you a

difficult

question what is

nothing imagine for a second a patch of

space with nothing inside of it it has

no atoms of space dust not even

radiation passing through it as near as

can be seen nothing exists within it and

yet is there really truly nothing there

something fundamental exists here and we

can tell that this is the case when a

beam of light travels through it if you

are familiar with the properties of

light you will know that light is

actually waves of electrical and

magnetic charge that are constantly

propagating with each other forwards in

a straight line however let's take a

look at that word wave a wave in the sea

is the propagation of energy moving

through the water if you were to look at

an individual particle of water it's not

really going anywhere except in a circle

and yet because it passes energy to the

atoms next to it energy travels towards

the shore in a constant motion that goes

all the way to the beach similarly a

sound wave moves by passing energy

between air particles with each particle

only moving a tiny bit becoming

energized and then passing that energy

to the next particle in

line but in our vacuum of space where

there is nothing in it where our Photon

of light is traveling in waves have you

ever stopped to wonder what exactly is

waving this hints at a fundamental

something that exists even in nothing a

fabric that makes up all of reality

itself Quantum physicists call this

something a Quantum field Quant Quantum

fields are tough to wrap your head

around but they are inescapably

important when it comes to understanding

the fate of a black

hole so how do Quantum fields and

exploding black holes tie together going

back to Hawking's paper Hawking

hypothesize that black holes would

release energy slowly over time in

initially tiny

quantities as energy and mass were two

expressions of the same thing according

to Einstein's famous eal mc² equation

this inevitably resulted in a reduction

in the black hole's Mass however as the

black hole shrinks the rate of energy

release would speed up getting faster

and faster until in the very last

moments of the black hole's life it

would release a burst of energy that was

truly gargantuan in its scale before

Vanishing

entirely but how can this be true it is

well known that an event horizon is

inescapable so how could radiation ever

leave it and eventually cause such a

black hole

explosion the answer is a strange one

and relies on unintuitive ideas of

quantum theory that completely go

against our day-to-day experience but if

it's true I hope you're prepared for the

universe to be a whole lot Stranger Than

You first

thought but to begin understanding

Hawkings Theory we need to understand

the idea of quantum

Fields remember light moves like a wave

through even a completely empty patch of

space which reveals that there must be

something existing even in the nothing

or else light wouldn't be able to wave

it scientists call this fundamental

fabric of reality a Quantum field in

fact they believe that there are several

Quantum Fields all overlapping each

other and all covering every single

patch of the universe be it past present

or future Quantum field defines a

particular type of something one field

might Define all of the electrons in

existence while another May Define

quarks that make up an atom where

nothing can be found the quantum field

is relatively quiet think of it like a

guitar string that hasn't been strummed

or a graph that has a zero

value but wherever in time and space

mass or energy can be found the quantum

field is resonating at that point and

when the resonance reaches a certain

threshold or quantity the universe

Express expresses that as say an

electron or a photon it's important to

note that in this Theory the resonance

is not just reacting to a piece of

matter it is the matter an electron is

nothing more than a resonating section

of the quantum field that defines

electrons this is true for all energy

and all matter too according to Einstein

energy and matter are two sides of the

same coin after all all the universe you

see around you is resonating quantum

fields and nothing more in this way the

theory portrays all of the universe as a

song being played on these fields which

I think is quite a beautiful image if

nothing else but why does this matter

why is it important to define the

universe in this way well due to an idea

of quantum physics called Heisenberg's

uncertainty principle sometimes the

strings of the universe start strumming

themselves without going too deeply into

this aspect of quantum physics

essentially when we're looking at really

tiny objects on the atomic scale it

becomes impossible to know too much

about them you cannot know both the

location and the direction of travel of

an electron for instance because it is

so small as soon as you try to figure

out the location of an electron it

bounces off whatever you are trying to

use to measure it so you can no longer

be sure of its direction of travel if

you know its direction according to this

principle you can't know its location

this is not just just because our

methods of measuring aren't good enough

but because of some fundamental laws

about the nature of the universe itself

according to Heisenberg's uncertainty

principle you cannot know everything

about particles on a subatomic level but

when you apply this principle to Quantum

Fields it gets weird Quantum Fields

fluctuate everywhere and by Heisenberg's

uncertainty principle particle and

antiparticle pairs can actually pop in

and out of existence the how and why why

get complicated but basically the

universe allows it as long as they only

exist for a very short period of time as

ruled by uncertainty

relations you might think this can't

possibly be a thing mattera does not

just pop into existence we would have

surely noticed this by now however in an

experiment done by hendrik Casmir

evidence was found that suggest that

this might actually happen kasmia took

two plates of conductive metal and

placed them close enough together so

that only certain sizes of smaller

virtual particles could pop into

existence between them this limited the

number of such particles that could pop

into existence but because all types of

particles could pop into existence on

the outside of the plates this meant

that there was a difference in pressure

exerted on the two sides of each plate

theoretically the larger pressure by the

number of virtual particles on the

outside of the plate should push the two

plates together and in the test this

proved to be the case

you might think that particles appearing

out of nowhere seems to defy the laws of

conservation of matter you would be

right so to balance the scales whenever

a virtual particle appears a second

particle also pops into existence to

pair up with the first particle but

while one of the particles is matter the

other is antimatter a one and a minus

one on our bar chart thus keeping things

overall at zero the universe is happy

and on top of that these fluctuations in

the quantum field quickly crash into

each other and annihilate each other

removing them both from existence again

so we don't normally have to worry about

them as a side note there is a theory

that antimatter is simply matter that is

moving in the opposite direction through

time but that's a level of weirdness

that we don't need to get into

here the important part is that the

quantum fields are constantly resonating

and constantly canceling each other out

this is why for for the most part empty

space is

empty however what would happen if you

stopped only some of those fields

resonating and that's where black holes

come in black holes act a bit like

putting your thumb on the guitar string

of the universe due to their event

Horizons certain resonances in the

quantum fields are dampened down while

others are not Hawking imagine sketching

a line through time in a patch of space

where a black hole was born he imagined

a Quantum field that resonated along

this line stretching from before the

existence of the black hole into the

future after it before the birth of a

black hole all is normal Quantum fields

are all resonating freely and can cancel

each other out however the emergence of

the black hole's Event Horizon changed

the curvature of space and outside it

Hawking realized that certain pulses

were now missing their opposite numbers

as he looked at the math he realized not

everything was being canceled out

anymore after the black hole had formed

indeed outside the Event Horizon

traveling away from the black hole he

found resonances that perfectly match

the shape of thermal radiation flying

away into

space radiation is energy and energy

cannot form from nothing as the black

hole was creating this radiation the

black hole would have to pay the price

every piece of Hawking radiation would

thus coincide with an equal amount of

energy lost from the black hole which in

time would reduce it down to nothing if

it exists Hawking radiation is kind of

like money spontaneously appearing

outside of a bank while inside the bank

the money in the vault

vanishes it's also extremely difficult

to prove as Hawking predicted this

radiation would be colder than the

background Cosmic radiation that fills

the

universe and would have a wavelength as

long as the black holes Event Horizon

itself as some black holes have event

hor Horizons the size of solar systems

we have no way of detecting this kind of

radiation we'd only really see it once

the universe had gone cold and dead so

there was nothing else to get in the way

which would probably mean we weren't

around anymore to do the

detecting however in spite of the

objections to it the math behind Hawking

radiation seems to be sound and

scientists have recently taken steps to

proving it in the lab in the techan

Israel Institute of Technology

researchers looking into Hawking

radiation came up with an idea to get

around the difficulty of measuring a

real life black hole they did this by

creating an analog a Sonic black hole

which would mimic the properties of a

real one they relied on the fact that

sound moves much slower than light so

it's much easier to create a medium that

moves faster than sound when it moves

any sound waves traveling in the same

direction as it can never quite Escape

it interestingly HW math worked for

these Sonic black holes just as well as

it did for Gravity based ones and so

Hawking radiation ought to be detected

from it after repeating the experiment

97,000 times over 124 days of continuous

experimentation the researchers detected

multiple instances of Hawking radiation

and saw that it matched Hawking's

predictions of how his radiation might

behave although this does not prove that

Hawking radiation is definitely real for

actual black holes 2 the fact that

Hawking's math worked for this Sonic

analog is a strong implication that he

might be onto something Hawking

radiation might just be

real so if you fell into a black hole

could you ever escape probably not

however if you waited until almost the

end of the universe the black hole may

just radiate Hawking radiation until the

mass and energy that made up your

existence was completely removed from

inside the Event Horizon does that count

count as

escaping that's probably not so

appealing to you probably best just not

to go in and that's not the only weird

thing about black holes their existence

implies something quite worrying about

our own

reality when you're walking on a beach

and you make a footprint in the sand

there is no question in your mind that

it is your foot that caused the

footprint the order of causality is

quite clear here so much so that it

seems laughable to even need to assert

it you made the footprint the footprint

didn't make you but what if it did what

if I told you that on the cosmological

scale the fundamental relationship

between foot and footprint might be a

little more blurred than you would

intuitively think and shockingly due to

the nature of black holes and Hawking

radiation there is some evidence that

this might just be the

case but to begin with we're going to

need to look at a principle called

relativity but no not that relativity

Galilean

relativity first described by Galileo

galile in 1632 the idea of this form of

Relativity is that there is no

difference between being completely

still and moving at continuous speed

imagine there are two rooms one on a

ship and another on land both are

soundproof and have no windows imagine

the sea is is calm so there's no rocking

at all the only difference between the

two rooms is that one is moving and the

other is not can you tell the difference

between the two from the

inside you might think that you'd be

able to sense movement but this is not

the case for instance right now you are

careening through space at 110,000 kmph

due to the Earth's movement around the

Sun and if you are sitting down at home

while watching it it's likely you would

have said you weren't moving at

all in fact Galileo realized that there

was no test that could be done to tell

the difference between the two

scenarios he even found that if you

dropped a ball in the ship from your

perspective it would look like it fell

straight down even if from the

perspective of a person on land it would

look like it was falling

diagonally Galileo realized that if you

remove all frames of reference Say by

being in space there is no way of

telling if a planet is moving towards

you or you are moving towards a planet

according to relativity both are equally

valid

interpretations you might have noticed

this yourself if you ever looked out of

the window on a train just as another

train suddenly passed by quickly

overtaking you although both trains are

going forwards the other train is going

faster than yours and because you no

longer have a frame of reference to

compare your motion to it might look as

if you are suddenly going backwards

Einstein took this idea further with his

equivalence principle here he took the

idea of two rooms again but this time he

was making an observation about

gravity if you were inside a windowless

room floating in the vacuum of space and

someone started accelerating your room

in the up Direction Say by strapping a

rocket to the bottom of it if the rocket

accelerated at just the right speed then

it would feel identical to if you were

standing in a room on the surface of

Earth

in other words there is no way to tell

the difference between the acceleration

caused by gravity and the acceleration

caused by a rocket assuming you couldn't

stop the rocket shaking you with all its

rumbling of

course both these principles rely on the

idea of inertia that objects do not like

to move if simply left on their own and

do not like to stop moving once they

have started anytime you want a mass to

do something different to what it is

doing a new Force must be applied

otherwise it will remain

inert but why would it feel to the man

in the room with the rocket as if he

were under the effects of gravity or

perhaps a better question why would it

feel to us on Earth as if we were being

accelerated upwards by the effects of a

rocket the Earth is not expanding in all

directions at once pushing us with it

surely while this is true Einstein

realized that the two felt similar

because they both were the same thing a

form of

acceleration however there is another

form of acceleration that better

explains how gravity Works than simply

applying a force to an object to push it

like a rocket does consider this

spinning Fair Ground ride if you have

ever been on such a ride you will know

the power of changing direction as a

form of acceleration when you stand

against the wall of the ride once it

gets up to speed you feel a constant

force pressing you against the wall even

when the ride spins at a constant speed

this is because your mass is trying to

move in a straight line at each point in

the ride but the curvature of the ride

is forcing you to alter your direction

the battle between your inertia trying

not to change what you're doing and the

wall trying to alter your direction of

travel manifest as the force you feel

and as far as acceleration is concerned

there's not much difference between the

earth beneath you accelerating you up

and you trying to accelerate down

Einstein realized that this form of

accelerating acceleration caused by a

curving path was the best explanation

for

Gravity he came up with a theory that

matter and energy cause a warping in the

space around it kind of like how a ball

might bend the surface of a Tor rubber

sheet it was placed on the larger the

mass the greater the curvature and once

space was curved any object trying to

travel through it would be deflected by

that curve in the words of physic phist

John Wheeler space tells matter how to

move matter tells space how to curve for

small masses this curve in space would

be very slight but in dense masses this

curvature could get so great that it

would be impossible for an object that

got too close to it to escape it these

are the conditions we find near a black

hole with its a vent

Horizon so going back to our very first

analogy of the footprint and the foot if

a black hole is the foot the curvature

of space around it is the footprint it's

interesting to see all of this in action

and to understand how Einstein came to

conclusions which would have been almost

universally validated by scientists even

a 100 years on but there's nothing

particularly weird about any of this so

far understanding the exact mechanisms

behind it doesn't make it any

stranger the black hole tells space how

to curve and once curved any object

moving near it is told how to move

nothing here is outside our expectations

based on day-to-day

observations but when we start to look

at Hawking radiation something very

strange happens the most important thing

to bear in mind about it for the

purposes of our current video is that it

is

nonlocal this means that it does not

appear from the black hole itself but

appears from the area of space around it

to be clear I do not mean Beyond The

Singularity of the black hole but still

within the black sphere here that's hard

to Define anyway space as we know it

doesn't exist there remember the black

ball you see here is simply the

demarcation point between inescapable

curvature and escapable curvature The

Event Horizon I do not even mean right

up against the Event Horizon although

that is sometimes how this theory is

portrayed people sometimes speak of two

particles popping into existence right

up against the Event Horizon with the

antimatter particle just inside it so it

falls in while the normal particle is

just outside and so escapes this is not

what is

happening instead the region of space

this radiation can pop into existence is

several times the size of the Event

Horizon a distance up to billions of

kilometers away and when the largest

black holes we have can comfortably fit

multiple solar systems side by side

inside of their Event Horizon the idea

that a photon of radiation can pop into

to existence this distance again outside

the Event Horizon is crazy it happens

even in a place where there is literally

nothing there so in short it is not so

much that Hawking radiation is coming

from the black hole directly instead it

is coming into existence from the

curvature of space that the black hole

is creating and can happen quite far

away from the black hole

itself but if that is true then things

work completely opposite to what we

might expect as you will see in a moment

consider what happens in this order as

energy leaves the curvature of space the

curvature lessens because of something

known as the conservation of energy and

as this reduction of curvature happens

the black hole then shrinks this is

crazy this is like the footprint getting

smaller and so the foot shrinks

accordingly it feels very wrong things

can't possibly work that way and yet I

Einstein hinted that such a thing might

indeed be

possible in one of his equations he

stated that the curvature of SpaceTime

was proportional to the mass energy of

an object but proportional is not

causational there's no presupposition

that one causes the other in this

relationship we are comfortable with the

idea of changing Mass and so changing

curvature but it works just as well if

you go the other way and change the

curvature to change the mass if this is

true then it hints at a universe where

mass is simply a projection caused by

space

curvature when you shine a light at an

object say your hand and it makes a

shadow on the wall the shadow is a

projection caused by the existence of

your hand interacting with the light

normally in this analogy you might be

forgiven for believing that we are the

hand it is our mass that creates the

curvature of space around us and yet do

we really know that it doesn't work the

other way around are we simply

projections Shadows on the wall of the

universe being brought into Life by

something more fundamental going on in

the curvature of SpaceTime and yet we're

going around thinking that we are the

thing that's real we don't really know

given that all you know is the reality

you experience it would be difficult for

you to be able to tell the difference

between the two

scenarios but if relativity has taught

us anything it's that if there's no way

of telling the difference between the

two situations then we can't completely

dismiss that we're in one and not the

other either that or the two might be

more linked than we

thought of course obviously this is all

just a theory there is no hard proof

that Hawking radiation is even a real

thing although there have been some

experiments that hint that it might be

but this is just something interesting

to think about and even if it does prove

to be the case that reality is a

projection it's not going to affect your

day very much you will still think and

feel and that's more than enough reason

for you to go about doing what you're

currently doing but it is an example of

how when we start to examine the very

fundamental building blocks of Reality

by exploring the weird warping effects

of black holes it can cause us to

challenge assumptions about our very

nature after all when you're asking the

question am I real and the answer is

it's not certain that's more than a

little

concerning either way black holes affect

our reality and they affect our universe

and not just because they suck

everything within their reach into them

and give nothing back they are the end

the final destruction of the universe

and yet what if I said to you that they

might actually prove to be our

Salvation black holes might provide the

answer to traveling faster than the

speed of light and solving the energ

crisis in ways we couldn't have even

imagined until

recently and as by now I have come to

expect they do so by messing with the

fabric of reality itself and by

completely countering my expectations of

physics perhaps we have been thinking

about black holes all

wrong but to understand how a black hole

ignores the usual limitations on faster

than light travel and does so in a way

that you can benefit from it without

having to go inside a black holes Event

Horizon and how it produces near

Limitless energy at the same time then

we are going to have to understand more

about the features of black holes than

we've covered so far it's actually quite

difficult to say much about the black

holes features at all precisely because

of the Event Horizon we cannot see what

the inside of a black hole looks like in

fact there are only three things we can

say about black holes with any degree of

certainty they have mass they have

charge and they have angular

momentum you might wonder how we know

these things about black holes given

that no light can leave them to tell us

about them the key to these three

characteristics is that all three of

them represent aspects of the black hole

that can be felt outside the black holes

of end Horizon charge for instance works

the same way around a black hole as it

does around any other charged object

that is to say if a black hole is

charged then it will attract objects

that have different charge to it and

repel objects that share its charge

think of it like a giant magnet pushing

and pulling on the universe around it

scientists can track objects that

approach a black hole and by seeing how

quickly certain objects known to have a

charge move towards it scientists can

predict the charge of the black hole

itself interplaying with this is

mass the mass of a black hole can also

be felt outside the sphere of the Event

Horizon in fact it is the main creator

of the Event Horizon in the first place

this is because Mass creates gravity and

does so in a linear fashion in

accordance with the same principles you

might find in gau's law a theorem about

electromagnetism albe it with a

gravitational

analog so it's possible too to calculate

the mass of an object by seeing how far

away objects are before they start to

accelerate towards it and how quickly

they accelerate although obviously you

need to factor in charge at the same

time or your results might get

skewed finally angular momentum or spin

it is possible to detect the spin of a

large mass object and we are going to

dive into the how in just a bit for now

let's just accept it as a given and

recognize that black holes are certainly

very high mass

objects there are varying sizes of black

holes in existence the smallest known as

micro black hes have a mass that's

comparable to that of our moon or 7.35 *

10^ 22

kg they fit all this into a space that's

just 0.2 mm in diameter which is

incredible it really gives you a sense

of how dense a black hole can be

something thinner in size than a human

hair packing the mass of the Moon and

that's just the smallest ones Stellar

black hole hes have a mass equal to 10

times our sun and have a diameter equal

to 60 km intermediate black holes are

the mass of 1,000 Suns and fit all of

that into a diameter of 2,000 km which

is still much smaller than the earth it

is the largest black holes that really

dwarf us with masses between 100,000 to

10 billion times the mass of the Sun and

sizes ranging from 0.001 1 to 400

astronomical units an astronomical unit

being the distance from the Earth to the

Sun but other than those three features

there are in theory no other differences

between them if you put two black holes

in the same room and made sure they had

the same mass charge and spin it would

be impossible to tell them

apart however these three features are

enough to have some interesting effects

on the area of space outside of black

hole traveling inside a black hole is

impossible space and time break down

past the Event Horizon but we think we

know a few things that must exist inside

one beating in the heart of a black hole

there is thought to lie the

singularity in truth this actually is

the black hole when we were discussing

diameters earlier that is just the

diameter of the Event Horizon again we

are not certain what the black hole

actually looks like because light can

never Escape it in a space that is

infinitely small there is a point where

all the mass of the black hole is packed

so that it is infinitely dense for the

simplest models of black holes the ones

that do not spin this is a single point

in a rotating black hole this is more

like a little spinning ring otherwise it

would be difficult to Define spin for a

point that has no

volume our current physics get very

strange around such a black hole

if ideal paths are traveled around this

point it becomes mathematically possible

to do some very strange things like meet

up with your own past this has some

disturbing implications for causality

and gets into time travel paradoxes like

the grandfather Paradox so that probably

only shows for certain that our ideas

about singularities are not quite right

yet because the singularity is so small

it'll take the successful merging of

quantum theory and general relativity

Theory to properly explain what is going

on inside a black hole and we have not

yet managed to do this it may one day

turn out that singularities do not exist

in the hearts of black holes at all but

this is the extent of our knowledge so

far well whatever it is that lies inside

a black hole it Powers our faster than

light engine because like most objects

in the universe it spins and oh does it

spin as we travel out from the center of

the black hole we passed through the

Event Horizon with a little Fanfare The

Event Horizon actually cannot be

detected locally although a person

outside the black hole might watch you

slow down to a complete stop as you

travel through it from your perspective

it actually might seem like time is

Flowing normally normally that is until

the universe outside the black hole runs

its course in an instant because time

outside the black hole is traveling so

fast compared to you this is the essence

of relativity

in fact the only evidence you might have

that you passed the Event Horizon at all

is because of something that exists just

outside it the photon

sphere in a Zone just outside the Event

Horizon there exists a point in space

where if a photon enters it at just the

right angle it will enter a perfect

orbit around the black hole in much the

same way the moon perfectly orbits the

earth this infinitesimally thin zone is

known as the photon sphere and given the

number of photons that have flown past

black holes in all the millions of years

they have existed it is probably filled

with photons it is quite possible that

you would be instantly fried as you pass

through this

point however it is just outside here

that we find the zone that interests us

the erosphere

this is the Zone around a black hole

where we can most easily detect its Spin

and this is because in this Zone it is

impossible for us not to move you see

Mass affects space we see this in the

curving effect of gravity on the Travel

of objects through that region of space

however it might be more accurate to say

that mass drags on the space around it

as it moves through space it brings a

little bit of that space along with it

for the ride and when an object is

massive as a black hole spins there is

an effect known as frame dragging to put

it simp simply reality around the black

hole begins to spin in a Whirlpool that

cannot be fought against much like a

real whirpool anything caught within the

ergosphere is spun around the black hole

because the frame of reference it sits

in is being

pulled sort of like how a person moves

because they are standing on a moving

walkway the greater the spin of the

massive object the faster this happens

and in the erosphere this can Ur at a

speed so fast that by The Event Horizon

space is moving faster than the speed of

light you would need to travel faster

than the speed of light in the opposite

direction just to stay at a relative

standstill from the point of view of the

outside Observer which of course you

cannot

do but isn't this against the laws of

physics doesn't Einstein say that

nothing can travel faster than the speed

of light the answer to that is yes but

black holes have found an interesting

loophole you see this rule only applies

locally right where you are in your

frame of reference nothing can go faster

than the speed of light but thanks to

relativity it is possible for frames of

reference to move away from each other

so fast that objects in them appear to

be breaking this light barrier from your

point of

view but if you moov next to them and

enter their frame of reference they

would seem to slow down and would start

obeying the laws of the physics again

it's a really weird effect but frame

dragging is an actual thing it is by

measuring frame dragging that scientists

can learn the spin of a black

hole however according to a man called

Roger Penrose there may even be a way of

exploiting it if you were to send a

rocket into this section of the

erosphere the rocket would speed up due

to being caught in the whirlpool of

reality once it had gained enough speed

it could then fire a propellant in such

a direction that it pushed itself out of

the whirpool again but now traveling at

a much faster speed this method named

the Penrose process could hypothetically

net you energy equal to about 20% of the

mass of your rocket now that might not

sound like much but remember according

to Einstein's eal mc² your 20% Mass

would produce energy equal to itself

Times by 299,792,458

458 squared that's a lot of

energy so to harness this colossal

kinetic energy all you would need to do

is travel to the nearest black hole

which is roughly 3,000 light years from

us and enter its erosphere with a rocket

capable of surviving the intense

gravitational forces there ideally you

would need to find one that was not

surrounded by an accretion disc because

those get up to temperatures of millions

of degrees as they are swung around at

near light speeds and melt from solids

down to gas and plasma but you get the

idea

easy okay maybe this is a little

impractical for us but the implications

for faster than light travel that black

holes demonstrate through frame dragging

might just offer us the key to one day

beat the light barrier for real not by

going faster than light ourselves but by

somehow convincing the frame of

reference we are in to travel at those

faster speeds just like they do around a

black

hole of course if this requires the

energy of a black hole to accomplish we

might be out of luck for now but it's an

incredible glimpse into what is possible

and scientists are already looking into

the power of frame dragging for Future

travel but maybe that's a topic for

another

video either way this all just

highlights once again how our universe

really is very different from what we

might have ever

imagined and here's another surprise

thing about black holes you may not have

known

before falling into a black hole is a

lot harder than it sounds you might

expect it to be relatively easy after

all and's the ultimate absorbers quite

literally the largest sources of gravity

out there shouldn't it be easier to fall

into them than any other thing in the

universe you might have thought so but

paradoxically your intuition is wrong

these Galactic moos are one of the

hardest places in the universe to

actually get inside so much so that

during his lifetime Einstein believed

you couldn't get inside them at all and

not only that but black holes might even

eject you away from them at speeds close

to the speed of light shouldn't it be

that these objects would be incredibly

easy to get into like a slide that gets

steeper and steeper the further along it

you go you might expect to speed up more

and more the closer you get to the black

hole

center however while this is right it is

also wrong you do speed up so much so

that your speed will begin to approach

the speed of light however in almost all

circumstances you will not find yourself

approaching the center of the black hole

and this isn't me talking about some

strange Quirk of time or relativity but

something that will be observable from

whatever frame of reference you're

watching from confused

don't worry allow me to explain through

the real world example of something

called an accretion

disc black holes are at their very heart

very simple in something known as the no

hair theorem black holes are said to be

devoid of almost any feature just like a

head with well nothing on it the

features of a black hole are usually

fairly plain too they have charge mass

and spin and that's about it as such a

cian discs are not actually a necessary

part of black holes black holes can

exist just fine without them sitting

there dark and unobservable in space

however when Mass such as an unlucky

star Strays too close to the black

hole's gravitational pull it can be torn

apart by the vast forces at work and

sucked towards the black hole center

strangely enough though this matter does

not all immediately fall into the black

holes of end Horizon instead the matter

usually coalesces into a sort of flat

ring that orbits around the black hole

outside the Event

Horizon while eventually it does all

enter this process can take a long time

some accretion discs take 100 to 1,000

million years to be completely absorbed

so what is going on here why does the

matter not simply enter the black hole

the answer is that it comes up against a

surprising principle of physics known as

the conservation of

momentum first described by

mathematician John Wallace in 1670 and

then pioneered by his contemporary

Newton a decade or so later the idea

goes like this if you have a group of

objects the motion of those objects AKA

their momentum collectively must always

remain the same if one particle with

momentum bumps into a particle that is

standing still and both bounce away from

each other the amount amount of total

motion for the two particles must equal

the amount of the first particle on its

own no momentum can be

lost if you have a rocket on a Launchpad

with zero momentum it can only give

itself momentum by firing a propellant

in the opposite direction once you add

up the amount of momentum imparted to

the air by the propellant going down and

the amount of momentum given to the

rocket by going up then the upward

momentum and the downward momentum are

equal resulting in the same Net Zero

momentum you had to start with this

Falls a little outside our

expectations after all we as humans

often stop and start walking around

seemingly without obeying this law

however if you evaluate all the

particles involved this law is always

kept you would struggle to move anywhere

without a floor to push against momentum

imparted to the floor must equal the

amount of momentum imparted to you but

in the opposite direction

you just don't notice it because the

floor is so much bigger than you the

amount of momentum you give to it does

not move it in any noticable way but

what has this got to do with falling

into a black hole well consider this

next example this time to do with

angular

momentum imagine a ballerina who has

their arms outstretched and is spinning

on a single point the particles in their

hands have momentum they are moving a

certain distance in a certain certain

amount of

time however when they tuck their arms

close to their body what happens well

they suddenly start spinning much faster

this is a classic example of momentum

trying to be conserved you see the

momentum in the hands is still trying to

travel at the same speed it was

previously traveling at however suddenly

because it's close to the body it's now

traveling a much smaller distance but is

doing so at the same speed effectively

it has much much less distance to travel

to complete one revolution and as a

result completes that Revolution much

faster this causes the ballerina to spin

faster when they tuck their hands in and

slower when they stretch their hands out

now imagine this on a cosmic

scale in most scenarios matter does not

fall in a perfectly straight line

towards a black hole almost always it

will miss it slightly and will start

spiraling in towards its Center as it's

caught in the black hole's gravity it

now has angular

momentum as it gets closer towards the

center of the black hole it starts

speeding up moving at the same speed on

a smaller and smaller orbit gaining more

and more angular spin the further down

the gravity well it falls just like the

ballerina you want to go a little

further in you have to spin a little

faster however unlike the ballerina this

matter has the speed of light to contend

with nothing in the universe can can

travel faster than the speed of light

this is a law discovered by Einstein so

what happens to our spinning matter as

it falls further and further into the

black hole due to the massive forces and

curvature involved it eventually reaches

a point where it cannot go any faster

it's hit a road block and because it

cannot spin faster it cannot fall

further into the black

hole this has several

effects to begin with as you can imagine

that creates friction all of this matter

spinning at such blistering speeds

around the edge of the Event Horizon

starts bumping into each other and when

this is taking place at near light

speeds things get very hot matter in a

black hole's accretion disc can reach

temperatures up to 10 million Kelvin

this is enough to melt anything down to

a hot plasma all these constant

collisions Pummel the atoms involved

causing them to give off more and more

of this energy like squeezing a lemon

this reduces their Mass between 10 and

40% of an atom's mass is given off this

way in the form of energy which then

radiates out Across the

Universe for a point of comparison

nuclear fusion the process taking place

in the sun converts only about 0.7% of

mass into

energy let that sink in for a moment

consider how bright the sun is at 0.7 %

how bright can a black hole's accretion

disc

get the brightest such discs are known

as quazars and they can reach

brightnesses that exceed 1,000 times the

total brightness of every star in the

Milky Way

combined the good news is that

additionally some of that momentum

starts to be shed with the departing

energy more gets shed by imparting it to

matter further up out of the accretion

disc as fast the moving particles knock

into slower particles moving just above

them giving them an extra push and

slowing down the lower particles in this

way matter starts to lose its angular

momentum and begins to finally fall into

the black hole itself more momentum can

be shed through one of the most striking

features of quazar and black holes their

Jets we don't understand everything

about these Jets how they form and what

they are comprised of and only a small

fraction of black holes with accretion

discs have them but current theories

suggest they are caused by magnetic

forces that are created by the spinning

accretion disc or even the rotational

power of the black hole itself which

draws up material from the accretion

discs and fires them out into

space it's likely that as the accretion

disc spins magnetic fields form in

keeping with ampers law due to all those

moving electrically charged particles

the power and shape of these field

fields are such that there is only a

narrow channel at the North and South

Poles of the black hole for particles to

escape these magnetic fields may work in

a similar way to the rifling on a gun

channeling particles down a narrow

Barrel particles moving at near

relativistic speeds have only one

direction they can go even though we

don't quite know yet why they go perhaps

they are like the steam of a kettle

fired out through the only Gap that

exists in the face of this incredible

gravitational and heat

pressure and when they go they go

relativistic Jets travel further than

the galaxies they originate from and are

often Millions if not billions of light

years long one jet with this catchy name

has his x-rays reaching Earth from 12.7

billion light years away albeit faintly

this is because the radiation produced

by such Jets is very focused in One

Direction in an effect known as

relativistic beaming or the lighthouse

effect when the beam is pointed away

from us it is much harder to see take

for example the now famous m87 Galaxy

here very clearly a relativistic jet is

detected by Hubble this is the one

coming towards us there is very likely

another jet but we can't see it because

it's going in the other

direction it's worth noting that this

energy does not come from the the black

hole directly remember nothing can

escape from a black hole instead the

matter and radiation come from the

accretion disc surrounding the black

hole and again a lot about these Jets is

still theoretical we can see them even

observe them moving over time but we

don't fully understand them or what

causes them our understanding of

accretion discs does not even fully

explain how conservation of momentum is

kept there is still some mystery about

where all the momentum goes but the

sheer power at play is

undeniable Einstein may have been wrong

it evidently is possible to fall into a

black hole but when some black holes are

firing material away from them at near

relativistic speeds for distances

spanning galaxies well it's evidently

possible to not fall into them too and

once you factor in the force of matter

that is millions of degrees hot pushing

out at you as they attempt to shed their

own momentum perhaps you wouldn't want

to get too close to one

anyway so we've seen how the or

inspiring effects of a black hole can

span entire galaxies but it begs the

question how big can a black hole

actually get finding the largest black

holes is not difficult all you need to

do is look at the center of large

galaxies these super massive black holes

have grown since their formation

billions of years ago more and more

matter fall into them continually

increasing their Mass the very largest

of these super massive black holes can

be billions of times the mass of our sun

however it may come as a surprise to you

to realize that some of the most massive

black holes we know of are actually the

youngest you see when we look at distant

galaxies we are also looking back in

time and the galaxies billions of light

years away often have the largest black

holes if the universe is only 13.8

billion years old and light takes

billions of years to reach us that means

the Galaxy we are observing can only be

a few billion years old at most from our

perspective pretty young for a

Galaxy surely though it should be the

case that nearer and thus older super

massive black holes are more massive

seeing as they've had so much extra time

to consume matter falling into them so

what's going on

here the very largest super massive

black hole we know of is known as ton

618 with an incredible mass of 66

billion solar masses by itself its mass

is comparable to the Milky Way

galaxy however ton 618 is exceptionally

far away and it's taking light emitted

by it 10.8 billion years to reach us

meaning we are observing it as it was

10.8 billion years ago this means it can

be at most around 2.8 billion years old

by comparison our own Milky Way galaxy

is approximately 13.6 billion years old

yet the super massive black hole found

at our Galaxy's core Sagittarius A star

is only 4 million solar masses the

andrometer Galaxy super massive black

hole while bigger is still only 200

million solar

masses one of the big factors to

consider here is the difficulty in

detecting and measuring black holes this

is still a really new field of research

as technology has only just allowed us

to start observing black holes in the

last few decades even then we can often

only observe the area surrounding black

holes that is before the event horizon

telescope came along but even that

telescope takes ages to image just one

black hole so our general understanding

really is still quite Limited in fact

most of the distant black holes we know

about can only be seen because they are

quazars ton 618 is a quazar matter is

pouring into the black hole's accretion

disc at an incredible rate and because

of this it's erupted into a

quazar quazars can only be sustained as

long as matter is falling into them

otherwise they revert back to dark black

holes it's hard to fully grasp the

physics of the accretion disc but it is

believed that the friction here is so

great the accretion disc of aaza by

itself can produce thous thousands of

times more light than entire galaxies

combined ton 618 produces as much light

as40 trillion Suns completely outshining

the Galaxy it resides in to the point

that we can't even see it from our

perspective however because quazars are

the brightest objects in the universe

they can be seen from very far away so

one reason for large black holes being

far away is down to something known as

malmquist

bias this is where brighter objects

further away appear more plentiful when

in reality we simply can't see the

dimmer objects at that distance implying

there may be an argument that the

largest super massive black holes are

actually distributed fairly evenly

throughout the Universe if a galaxy has

a very large black hole but it's not a

quaza it means we won't see it after a

certain distance because a galaxy is

much dimmer than a

quaza another reason why we don't see

the biggest black holds close to us is

due to the nature of the universe itself

shortly after the big bang as you may

know the universe is ever expanding and

during the early Universe matter was a

lot closer together quazar were more

common back then because they need

extreme amounts of matter falling into

them to give off light and there was a

lot more gas around during the early

stages of the universe not only has the

universe expanded but over time gas gets

converted into Stars some of the largest

types of stars eventually turn into

neutron stars and black holes themselves

meaning that they never get recycled

back into gas less available gas means

less gas will fall into a super massive

black hole one of the theories for the

fate of the universe is actually based

on this called the big freeze where

after some trillions of years all the

gas in the universe is eventually

converted into black holes even now we

see some galaxies where their gas has

been completely used up meaning no new

Stars can form these are called

elliptical galaxies spiral galaxies

still have gas and dust structures and

thus can still produce new stars it is

interesting that most of the largest

super massive black holes appear to be

in elliptical galaxies where there is no

gas left gas needs to lose momentum to

fall into the Galaxy's Central super

massive black hole and if that happened

then the supermassive black hole is

likely to be much bigger because of all

the infalling matter with elliptical

galaxies this is already happened

whereas with spiral galaxies this hasn't

happened to the same extent one such

trigger for gas losing angular momentum

could be the gravitational influence of

nearby galaxies or even collisions with

other

galaxies in addition there is less gas

available in the universe now than there

was during the early universe so black

hole growth probably occurred rapidly

then but a slowed down now this might be

why there is no quazar within 500

million light years of us as the

universe ages and Things become less

chaotic and more spread out the number

of active quazar has decreased which

means the only quazar we see some of

which are the largest black holes we

know of are the ones that happened a

long time

ago so why are the largest super massive

black holes often the youngest well

although it may appear that way it might

not actually be the case at all we we

can measure distant bright quazar simply

because we can see them older and closer

black holes may also be large but

because of malmquist bias we haven't

found them yet as studies continue and

Technology improves we'll start to get a

more complete picture of the universe

around

[Music]

us we've discussed black holes a lot on

this channel because they are

fascinating regions of SpaceTime where

curvature is really pushed to the

extreme they exhibit features and

phenomena far beyond any intuition we

could have built from classical physics

here on Earth but despite all the

attention they've been getting black

holes aren't the only way SpaceTime can

show off its beautiful Curves in theory

they can be equally curved regions of

SpaceTime called white holes which get

their name because they are in many ways

the exact opposite of black holes and in

some cases a black hole and a white hole

can be connected connected by a totally

different type of SpaceTime called a

wormhole which functions as a kind of

limbo zone between parallel

universes if you've heard of space

travel through wormholes and thought it

wasn't more than just a fancy sci-fi

invention I don't blame you after all

even though these regions are possible

in theory there isn't any evidence that

white holes or wormholes actually exist

in our

universe but 100 years ago it was black

hole that were purely theoretical and

now we think there are literally

billions of them out there for our

telescopes to see so in this video we're

going to try to answer three questions

for you just what are these other holes

that we can have in SpaceTime should we

have our hopes up that they might be

more than science fiction and what do

they look like if they are

real I'm Alex molan and you're watching

astram join me today as we explore the

different types of SpaceTime that can

result from extreme

curvature I think the possibilities will

bend your mind as much as they warp the

fabric of the universe around

them before we dive into the physics of

SpaceTime described by Einstein's theory

of general relativity I want to start

off with a simple analogy if I ask you

to imagine a cone you'll probably think

of either something that points up like

a traffic cone or something that points

down like an ice cream cone these are

what we think of as cones in the real

world but if you write down the most

General mathematical equation for a cone

and try graphing it you'll get something

that looks like two cones glued together

you see a mathematical cone has two

halves one that points up and one that

points down connected at their tips and

what we think of as cones in the real

world are actually just chopped up

pieces of the full mathematical

cone black holes are exactly the same

way let me explain many of the black

holes we see in the universe are

remnants of massive stars whose extreme

gravity caused them to collapse in on

themselves once a black hole is created

it becomes permanently separated from

the World Around It by a spherical

barrier known as The Event Horizon

anything can fall into the black hole

but nothing not even light can come out

this structure of SpaceTime can be

neatly summarized in what physicists

call a pen rose diagram which is a way

of representing an infinite SpaceTime in

a finite drawing the key feature of a

Penrose diagram is that light travels

upwards at 45° angles making it easy to

distinguish regions where light can or

cannot enter in this diagram region one

is the regular Universe containing the

original Star before it turned into a

black hole and everything outside it

from the infinite past to the infinite

future region two is the black hole and

is separated from the rest of the

universe by its Event Horizon you can

see how it's easy for light to enter the

black hole region two but it's

impossible for light to exit it will

inevitably hit this Singularity instead

the same holds true for ordinary matter

which moves slower than light and so in

this diagram can only travel upwards at

Angles steeper than

45° so what's so special about this

Penrose diagram is that it accounts for

the formation of the black hole at some

specific point in time when the star

collapsed in on itself in the far past

there was no event horizon or black hole

to speak of and light could travel fre

really across all of space but while

this diagram represents the kind of

black hole we're used to seeing in the

real world it's only one piece of the

full mathematical description of black

holes in general

relativity in other words it is the lone

ice cream cone of black hole

diagrams so what happens if we forget

the real world and imagine an ideal

black hole with an infinite past leaving

behind the baggage of collapsing stars

and everything else in the physical

Universe what is the black hole analog

of the full mathematical cone it might

look like a simple extension of our

original Penrose diagram but this

diagram comes with physics that's a

little upside

down region one is still our regular

universe and region two is still a black

hole with an inevitable singularity in

its future but the maths also describe

something that looks like the inverse of

a black hole in Region 3 instead of a

singularity in its future Region 3 has a

singularity in its past and if you draw

the motion of light rays at 45° angles

you see that it's straightforward for

light to leave Region 3 but it can never

enter it this type of region is exactly

what we would call a white hole it's the

SpaceTime analog of a traffic cone

but that's not all if you look beyond

the white hle you'll see there's a patch

of SpaceTime labeled Region 4 with the

same connections to the black and white

holes in the middle of the regular

Universe this patch is a parallel

universe and it's entirely disconnected

from the universe in region one since

it's impossible for even light to travel

from one region to the

other the upshot of all this is that the

same mathematical equation describes

desing the regular universe and the

black hole also describes the parallel

universe and the white hole this doesn't

mean that every black hole comes

attached to a white hole though just

like with cones the real Universe can

contain chopped up pieces of the full

mathematical solution but this does mean

that even if white holes are less common

than their black hole counterparts or

even if there aren't any white holes

connected to our universe at all it

doesn't make them any less scientific in

the sense that they are equally

consistent with the laws of

physics in our analogy if you imagine

that ice cream cones remain extremely

popular while traffic cones become

difficult to produce and are phased out

of existence that doesn't make the idea

of a traffic cone any less

real this is more or less the status of

white holes today the notion of a white

hole makes perfect sense but it's Poss

possible that any white holes that

existed in the past were unstable and

were similarly phased out of existence

if you're wondering whether there could

be some more stable white holes that

have just escaped our sight you're not

the only one and you should stick around

for when we talk about the tiniest

possible white holes in just a few

minutes but first I want to make sure

we're not leaving anyone hanging I

promised you wormholes I promise you

parallel universes that are actually

connected to each other so buckle up

because we're about to go to to a whole

new level of warped

SpaceTime the noad theorem says that a

black hole can have up to three

intrinsic properties Mass charge and

spin but the Penrose diagram I showed

you only described the simplest kind of

black hole which was electrically

neutral and completely stationary the

diagrams for charged or spinning black

holes are much more complicated but

they're also much more exciting in

because they completely alter our

understanding of singularities and they

give rise to new and fascinating regions

of

SpaceTime let's have a look at the

Penrose diagram for a spinning black

hole as an example instead of four

distinct regions of space time there are

now eight types of regions that repeat

themselves in an infinite pattern of

universes region one through four are

the same ones we saw before these are

the regular Universe the black hole the

white hole and the parallel universe but

now that the black hole is spinning its

geometry no longer has an unavoidable

singularity in its future and the white

hole similarly loses the singularity

that existed in its

past so what actually happens after you

cross the Event Horizon of a spinning

black hole at first you'll be drawn

towards the center of the black hole

just like you'd expect but eventually

you'll cross a threshold known as the

inner Horizon Beyond which the geometry

of SpaceTime unw warps and lets you stop

yourself from falling even deeper in

these innermost regions marked five and

seven you can float freely towards or

away from the center of the black hole

you could even touch the singularity if

you wanted to though I wouldn't

recommend it here in these innermost

regions of a curved rotating SpaceTime

you are officially in a wormhole and if

it weren't for the fact that you are

permanently separated from everyone who

stayed in region one this would have

been the perfect time for you to brag

about your wild Space

Adventures at this point you're also

faced with a bit of a fork in the road

one option is to keep moving Inward and

go around the singularity which takes

the shape of a ring instead of a point

for spinning black holes this path would

take you to region 6 or 8 in the diagram

but it's quite possible that the

existence of this path is actually a

flaw in the predictions of general

relativity rather than a true

description of reality because going

even in a single loop around the

singularity can lead to causal paradoxes

where you visit your own past a safer

bet would be to turn around and move

outwards Crossing back into the inner

Horizon that you just came out of this

would take you into Region Three a white

hole which would then then carry you all

the way out to a brand new universe

similar to the structure to the one you

started out in originally but sadly

without your friends or family waiting

for you in fact by the time you get here

your old universe will have already

experienced an infinite amount of time

you would be living in a whole new

definition of the

future okay let's step back into reality

as fun as that Journey Through the

Wormhole was in theory you probably

couldn't survive it in practice and

honestly there's a good chance that the

Wormhole itself would collapse once you

disturbed at SpaceTime so how much of

this mathematical structure can we

expect to see in the real world spinning

black holes with event Horizons appear

to be everywhere in the universe but

what goes on inside of them is still

largely unknown there are two main

reasons for why physics inside real

black holes might be different from what

the Penrose diag would lead you to

believe First when black holes form from

the turbulent collapse of massive stars

some assumptions that went into making

the Penrose diagram are violated like

that the black hole existed forever or

that the Universe around it is perfectly

symmetric and doesn't contain random

infalling humans and second the theory

of general relativity used to construct

the Penrose diagram might itself only be

approximately correct breaking down near

The Singularity where the curvature gets

most extreme so there's a good chance

that some predictions of the diagram

especially the most problematic ones

involving singularities and time travel

paradoxes aren't real features of a

highly curved SpaceTime but the

existence of white holes is more of an

open possibility leaving plenty of room

for speculation about how they might

come to be and whether they might leave

any observational Footprints for us to

discover

one hypothesis that's recently gained

some traction is that a white hole is

born whenever a black hole dies and no

this isn't some magical story of

reincarnation or Voodoo it's a genuine

attempt to understand the full life

cycle of black holes with at least some

level of mathematical

backing you see even an isolated black

hole in an otherwise empty space will

continuously emit particles known as

Hawking radiation causing it to

gradually shrink and lose Mass over time

but once the black hole reaches the

super tiny plank Mass just about 20

microgram we have no way of predicting

what future awaits it at least not

without a full theory of quantum

gravity this is where Loop quantum

gravity comes in a proposed link between

gravity and quantum mechanics in which

space itself is made of discrete Loops

in short the equations of loop Quantum

Gra gravity predict that instead of

continuing to shrink even smaller than

the plank Mass such a tiny black hole is

instead more likely to Quantum tunnel

into a white hole spewing out its

contents back into the universe over an

extended period of time incredibly even

though this white hole will be similarly

small and light it can contain an

enormous amount of entropy because its

interior geometry will have been

stretched into a thin tube with an

extremely large volume

this store of entropy could potentially

open a pathway for any information that

falls into a black hole to be recovered

in the distant future solving a decades

long problem in theoretical physics

known as the information

Paradox as the white hole releases this

information it begins to slowly Fade Out

of existence the SpaceTime around it

loses its curvature and its life cycle

comes to a

close but before this video comes to a

close let me leave you with one last

thought in general relativity our whole

universe is predicted to have had a

singularity in its past namely 14

billion years ago at the moment of the

Big Bang in this way the universe is

like an uncharged stationary white hole

but if Loop quantum gravity says that

white holes can be born when black holes

collapse could the same be true about

the creation of our universe

could it be that our expanding Universe

was born From the Ashes of an older

Contracting

SpaceTime as crazy as this seems Loop

quantum gravity says that may well be

the

case but there are so many different

ideas for how this transition could have

happened that we would need a whole new

video just to scratch the

surface so if you want to hear more

about how the big bang could have

actually been a big bounce let us know

in the comments below the history of the

universe may hold more surprises

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and work which we were only able to do

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