Original subtitles

(MYSTERIOUS MUSIC)

- [Narrator] Since the very beginning of time,

man has looked to the night sky and asked the same questions,

where are we?

How far do the stars go?

And are we alone?

Today, these same questions linger

in the minds of every human with an inquisitive nature.

Is our world just a speck in an infinite universe,

surrounded by many other worlds and species?

Or is it possible that we are the only intelligent

life in the universe?

If our universe is truly infinite,

then it is thought that anything that could happen

has happened an infinite number of times.

There will be infinite worlds and infinite

intelligent life forms, even infinite copies of ourselves.

But we may also exist in an infinite universe, which

is one of infinitely many universes, each existing in

possibly infinite dimensions.

This series explores the many theories and ideas

as to where we all are in this immense system, which

seemed to come from nothing in the Big Bang

13.8 billion years ago.

New understanding says this may not be the full story.

We look at the ideas and theories

from a human perspective, and hear from our best scientific

minds, who spend their lives trying to understand

these monumental concepts.

(EPIC MUSIC)

How do we try and understand what may be simply

beyond human comprehension?

(EXPLOSION)

- [Narrator] The Big Bang is thought to be

the creation of everything, space, the stars,

the planets, and us.

How did all this come into existence?

When we look into a star-filled sky,

we are left with a feeling of awe

at the majesty of the universe.

(ENIGMATIC MUSIC)

How does the sight of the cosmos

make us feel about our place in all of this?

- [Speaker 1] When I look up at the stars,

the feeling that I have, yeah, it's hard to describe

because it's so beautiful that-- that there

is something that never stops.

- [Speaker 2] Whenever I see the stars and see the vastness

of it, and knowing that I know so little of what I see,

but what I see is so vast.

- [Speaker 3] I'm sure there were people living in caves,

looking at the stars at night and wondering,

how far those stars went?

- [Speaker 4] Stars are pretty much

just lights that look down on us, but in the daytime, they--

they're not there because they have

to go look down on other people somewhere in the world.

- [Speaker 5] Or I get a sense of beauty.

And that contemplation does arise about how we are here

on the Earth are just a tiny speck in an incredibly

vast universe.

- [Speaker 4] I wonder how long does it go for.

Like, how far is the sky?

Like, how far does the sky go?

- [Speaker 6] As a kid, I used to lie on my back

in the backyard and look up at the sky and think,

I wonder how many of those stars have planets.

I wonder how many of those planets got civilizations

looking back at us.

I wonder how far it goes on for.

- [Speaker 7] To think that what we see in the night sky is

this light that's millions of years old is mind-boggling,

but beautiful.

It makes me realize how little we are, that it takes

so long for light, which travels so

incredibly fast to reach us.

- [Speaker 8] We're observing these distant galaxies,

and something appeared on my screen that we'd observed.

And I was like, what is that?

And I couldn't figure it out.

And it was a spectrum of something.

And I asked my friend.

I say, Scott, what's this?

And he's like, oh, it's a quasar.

And it turned out that this was something that had emitted

the light that I was seeing in my telescope

over 12 billion years ago.

So I was seeing light that was emitted

from way before the Earth had even formed.

And the first thing that that light

had hit in all of that time was the mirror of my telescope.

I pushed back from the table.

I was like, whoa, that's astonishing.

- [Speaker 9] Looking at the stars and seeing light that you

know was emitted from those stars

is a very awe-inspiring, but also a very strange experience.

We're actually seeing the way the universe was.

That's really the only time as humans

that we can look into the past.

- [Speaker 10] I have never lost my sense

of awe at the night sky.

And in fact, when I came to Australia,

I saw the Large Magellanic Cloud for the very

first time with my own eyes.

This is a satellite galaxy of our Milky Way.

You can't see it in the north.

The Earth gets in the way.

And I'd studied it for years at university.

And there suddenly, I could see another galaxy

across this impossible vast distance,

but there it is, just hanging in the night sky.

That sense of wonder, the sense of awe,

that sense, that glimpse into a scale that is

far beyond, that of us humans.

If I ever want to get inspired, if I ever want to recreate,

I simply have to go somewhere dark to look at that night sky

because you never lose that sense of wonder.

You can study it for your whole life.

The night sky is still the most inspiring site I can imagine.

- [Speaker 6] I want to find out if there

are other people up there.

I want to find out how far it does go.

I want to understand what's up there.

- [Speaker 11] I don't mind the sense of feeling

absolutely minuscule.

In some way, I find it very exciting

to be even the tiniest part of such a mind

bogglingly huge system.

- [Speaker 9] It is when humans stargaze that they do start

to think about eternity, about infinity,

about what's out there, is there anything beyond us?

- [Speaker 12] The concept of infinity is bound up with

a sort of mystery, a human mystery

about the bigger scales and the biggest things you can imagine.

And I think as a child, and also just as a scientist,

it's an awe-inspiring thought.

It's like a question mark.

You can't really describe something

that's truly infinite.

- [Speaker 2] When I see how vast it is, I

see how small my problems are.

There is so much more out there, and that whatever

small issues I'm going through are nothing compared

to the workings of the stars.

- [Speaker 6] I'm very comfortable with being in awe

of what a fantastic universe we live in, and how

mind-bogglingly amazing it is that we,

puny humans on this planet, can find out so much

about it without really even leaving

the surface of our planet.

- [Narrator] The vast nature of the universe is obvious,

but the scale of it is beyond human comprehension.

It has been approximated that there

are more stars in our viewable universe

than individual grains of sand on every beach

and desert in the world.

Considering that the stars are light years apart,

it indicates that nothing can truly

make us understand the gargantuan nature

of the universe.

Such huge scales are simply too much for us to conceive.

We live in the two-meter scale, and

everything that is around us is relative

to our two-meter bodies.

Although we can see a vast mountain range and a tiny speck

of dust with our own eyes, there is much, much more

to reveal.

We have been very clever in the last century,

building ever more powerful telescopes

and microscopes to peer into previously unseen worlds.

We have observed many things, from the tiniest bacteria

to the vastus galaxies.

We are now delving even further into the tiniest with the

Large Hadron Collider at CERN.

But this is only the beginning of our understanding,

and the scale of the universe is still unexplored.

50 years ago, we used to think that the atom

was the smallest particle.

(ATOMIC ZAPPING)

- [Speaker 13] The atomic age was born.

Here is the answer to a dream as old as man himself.

The atom, a particle so infinitely small

that it takes over 100 billion billon atoms

to make up the head of a pin.

Just as other millions and quadrillions of atoms

are the tiny building blocks, which make

up everything in the world.

- [Narrator] Today we know of many smaller particles,

and this may be only the beginning of our understanding.

But let's start with our universe's outward dimension.

(ENIGMATIC MUSIC)

How big is our universe?

Do we truly understand its scale?

Throughout history, man has looked ever further

to discover the answer.

In 1996, the Hubble Telescope was

pointed at a tiny empty patch in the night sky.

After 10 days of exposure to this seemingly empty patch

of sky, the telescope revealed over

3,000 galaxies and hundreds of billions of stars.

The truth is that we cannot conceive of the vastness

of the universe.

It is simply beyond our grasp.

All we can see with our current technology

is only a fraction of what may exist

beyond our observable universe.

Even if you take infinity out of the equation.

- [Speaker 12] If you shine a flashlight at the moon,

it takes one second to get to the moon.

If you shine a flashlight at the sun, it would take,

you know, eight and a half minutes or so to get there.

And you imagine then, if you took the same flashlight

and you shone it across the universe,

it would take 13.7 billion years

for our flashlight to reach the edge of the universe

is-- we think about it.

- [Speaker 14] So the universe seems unimaginably big.

It has this radius.

That light has traveled for 13.8 billion years to reach us.

If we go through and ask, how many planets

there are in the universe?

There are more planets by a factor

of maybe 1,000 or so than there are grains of sand on Earth.

But grains of sand on Earth, that's a huge number,

but it's not infinite.

- [Speaker 10] Even the scale of the solar system,

the tiniest scale in the grand scheme of things,

is beyond human comprehension.

To actually visualize the distances

between the stars, the closest star

to about three light years.

I say a number, like, three light years, as if that's

a sma-- like, a centimeter.

It's like three centimeters.

It is a tremendous-- it's a trillion, trillion kilometers.

It is a distance that at our fastest rocket ever achieved

would take thousands of years.

This is not a conceivable distance.

And that is a yardstick.

That is the unit that we choose to describe our universe by.

We have objects like our own Milky Way, stretching

100,000 light years across.

An inconceivable distance.

Using a unit that is itself inconceivably massive.

Now we stretch that out.

Millions of light years from across,

we can have structures called galaxy clusters,

where entire galaxies whirl around each other

in the same way the planet goes around the sun.

It isn't even possible to begin to understand that scale,

yet so far away are they that we can actually

take a picture of them, and they're all there

and they're looking lovely, buzzing around each other,

held together, actually by the gravity of dark matter.

And that's one of the first examples of this idea

that there was something extra in the universe.

When you go to billions of light years,

well, now we've zoomed out to such a scale

that even the galaxies are no more than points of light.

And in fact, they create a-- a pattern

that looks absolutely the same from one point

in the universe to another.

In other words, we've now zoomed out

to such a scale that our universe is the same in one

location as another, and that is the idea that we are not

in a special place in our universe,

that you could travel a billion light years away to a galaxy

there, and the laws of physics should stay the same,

that everything should behave--

Certainly, that particular instance of a galaxy

may look a little different to the Milky Way, but not by much.

In other words, it's like being a tourist in modern-day life.

Everywhere you go you see the same shops,

you see the same kind of things.

We've had globalization on a cosmological scale

from the beginning.

The universe really does look very similar in all directions.

- [Narrator] Although this view is true from our current

viewpoint in space, perhaps when we can zoom in more,

the more difference we will see.

An interesting analogy might be that here on Earth, flying high

in a plane, all towns and cities

may appear to be similar, but it's not

until you land that you find vast differences,

different language, people, food, and cultures.

Perhaps when we view distant galaxies

and stars from our vast distances,

they do appear to be generic.

- [Speaker 10] I love the idea that

flying above a city, one city looks very similar to another.

That's actually because people build

cities in very similar ways.

One galaxy may look very similar to another,

and certainly, that's the case when we look out to the level

of detail that we can see.

If you were to zoom in and you were to find a star,

by and large, they all look pretty much the same.

Some are bigger, some are smaller,

they have different properties, but you

can find a star that looks pretty

similar to the one we know.

You can zoom in on a planet, and that's

when it begins to get interesting because not

all planets are alike.

They can be roughly the same size,

but the Earth in particular has very different conditions.

And the reason is life, because life makes up its own rules.

- [Narrator] When we look at our planet from space at night,

we can see the true impact of humans.

Our cities are glowing with lights,

which of course, are the signs of huge urban populations.

This would have looked vastly different only 100 years ago.

So is life the thing that will shape all planets?

- [Speaker 10] One moment in time on Earth looks very

different to another of the past, because life

is changing its own rules.

Physics is the same.

The atoms fundamentally are behaving the same way.

But it's because the life that is

around at that point in history interacts,

and that interaction changes the way it evolves.

And you fast forward and you get something

looking completely different.

(DRAMATIC MUSIC)

- [Narrator] The spectrum of scale in our universe is

mind-blowingly vast, going from the most distant

galaxies to the tiny bacteria that make up a huge part of us.

So the scale of things is absolutely vital to the way

we perceive things.

Too large and we simply can't see it.

Too small and we also cannot see or perceive of it.

For example, we are host to tiny cells in our bodies.

We have at any one time about two kilograms of bacteria.

They actually outnumber our own cells

and yet we are completely unaware of their existence.

- [Speaker 11] I find it intriguing that as we look

at the world that literally surrounds us physically,

that what we see as a particular

point or level where we exist.

But if we can go into, for example, our own bodies,

we can go into our organs and then into our cells

and then into the-- the tiny microstructures,

within our cells, and then within those

down to the chemicals and the molecules and the atoms

and down and down and down, smaller

and smaller and smaller.

And then we can go up the other way,

you know, and we can take our individual persons

and then, you know, all life forms on the planet, and then

this planet and galaxy and the universe

and so on and so forth.

And so that whole process of either going right down

or right up in terms of scale.

Has such vast variation that in terms of keeping perspective

of where we are, we just need to be aware

that we're at a particular point on a,

you know, sliding scale of--

of existence or consequence, that

happens to be of consequence to us because that's where we are.

As we go either up or down in that scale,

those consequences slip away.

- [Narrator] When we think of infinity,

our minds instantly think of the cosmos and beyond.

But is infinity a two-way street

going in both directions from the immense

to the infinitesimal?

- [Speaker 15] When someone poses to you what is infinite,

your mind instantly goes-- (IMITATES EXPLOSION)

Your mind instantly goes to the-- to the macro

rather than the micro.

- [Speaker 2] Because of the concept of infinity is so vast

and it's continually expanding, you have

to have the opposite to make it work as well,

which is contraction.

And with contraction it would become

infinitely smaller as well.

And over time, we've been able to prove that every time we

think we know the smallest particle,

we find something even smaller.

I mean, it was atoms, and now we're looking

at quarks and-- and beyond.

- [Speaker 3] So we're so used to having a scale,

to having a yardstick and working out that the yardstick

might be, um, millions and millions

and millions and millions of times longer

than we'd ever imagined.

I think that is really hard for us.

- [Speaker 9] Things can be, uh,

very, very large, like the universe or the space time.

So things can be very, very small.

It's natural to go for that symmetry.

But in fact, we don't know whether that symmetry

really, um, exists.

It may be that space is infinitely large,

but there are, um, limits to the size

that material things can be.

- [Speaker 16] My best guess for the universe is that

somehow we're just a patch of something much larger

that could have quite different properties in different places.

- [Narrator] If we are a part of a larger universe,

what form could that take?

And does that mean that in turn, we

are a host to perhaps billions of much smaller universes

that exist within our own universe?

- [Speaker 17] It's certainly an idea that people have played

with, this idea that our universe is a universe within

another universe, and what's more, that there are universes

within our own universe.

So one way of thinking of that is a kind

of nesting, which is universes within universes

within universes.

Or you could think of it more as a kind of a serial.

So it could be that universes beget universes, which beget

universes, but none of them is kind of

nested within the other.

But it's that they give rise to the next universe.

And either of these are kind of ways

of thinking about a similar issue,

but in slightly different terms.

- [Narrator] This nesting is well illustrated by the toys

known as Russian nesting dolls, where

inside one doll is an identical smaller doll, and so on.

Could our universe be similar in nature?

- [Speaker 18] Our understanding

of physics and science is a lot like

these Russian nesting dolls.

You open the nesting doll of the universe, you get a galaxy,

a galaxy, you get a solar system,

solar system, you get an Earth, Earth, you get molecules,

molecules, you get atoms, atoms, you get protons,

protons, you get quarks, quarks,

you get some other stuff.

But if you put them all back together,

universe, well, there could be brains

that all have the universes and brains,

something blah has all the brains, and so on.

And what we're trying to do is we--

we work in one of these shells, we work

in one of these nesting dolls.

So in astrophysics and what I'm working at,

we're working right now on the-- the universe

nesting doll.

And the particle physicists are working

on the very small nesting doll over here right now.

But it's not to say that they won't find a smaller one,

and we won't find a larger one.

But the great thing right now in physics

is this small nesting doll and this very large nesting doll

actually works back together.

(INTRIGUING MUSIC)

- [Narrator] Another good example of the nesting

concept are fractals.

Fractals are infinitely complex patterns

which, when either expanded or reduced,

become identical versions of themselves at different scales.

- [Speaker 18] A really great mathematical thing

is something called fractals.

And what is-- when you look at a shape

and you zoom in on one little small part of the shape, that

shape, that small shape is actually the same size

as the big shape, and so it keeps

replicating and replicating.

So we do know there are things of infinity in our universe

that we use, and we do know that there are

things like these fractals.

So if we zoom out, it'll get larger

and the larger picture will just be the smaller

picture almost blown up.

It's just this self-replicating system.

And if you go down, it goes like that,

but it's still the same picture.

- [Narrator] The idea of the universe being

infinitely scalable, a bit like these fractals,

is an amazing thought.

One of the hard things for science to resolve

is the laws of physics that apply to these vastly

different scales.

As scale changes, so do the laws that govern them.

We cannot apply rules universally to all things

in our universe, and new scales as yet

undiscovered are almost certainly

going to reveal themselves.

- [Speaker 18] So we have quantum physics,

which is small, and Newtonian physics,

which is medium, and Einstein physics, as I'll call it,

which is large.

We know there's questions this way

that Einstein physics, right? quite can't understand.

We know there's quantum physics questions this way

that quantum physics questions can understand.

So there probably is another smaller scale, another larger

scale up there of physics that when it all works together,

it all works in a different scales.

You couldn't apply quantum physics

to describe how planets move around a star,

or how a galaxy acts.

Just doesn't work because they're completely different.

They really are apples and oranges,

but when you look at quantum physics

and apply it to quanta, so small particles,

it works marvelously, but it also shows we have a lot to go.

- [Narrator] So is it possible that there is a smallest

building block of the universe, a particle that makes up

everything that can no longer be divided into smaller parts,

and the limit of the universe in the smallest

scales is reached?

- [Speaker 19] Will we ever find out whether, um, space

is infinitely divided up?

Or whether there is a minimum unit of distance?

Or that time is infinitely divided up into moments

that have no duration?

Or whether it too is as it were, quantized?

- [Narrator] Quantization is the term given to labeling

the smallest bit of something that exists,

whether it is time or space.

Or is it possible that no limit and no smallest piece

exists and everything is infinitely divisible?

(MYSTERIOUS MUSIC)

- [Speaker 20] Richard Feynman once argued that it

doesn't make sense to talk about

units of space and time smaller than Planck length space-time.

If that's the case, then in fact,

there's just a finite number, a large number,

but a finite number of bits of space between any two points.

Which is the right answer?

We don't know at this point.

- [Speaker 8] Uh, this table in front of me,

it looks continuous, but in reality, it's made up of atoms.

It might be that space and time seem continuous,

but they actually might be quantized as well.

They might be made up of smallest

bits of space and time.

It's not like there's emptiness in the gaps.

And it's not even that there's-- there's nothing.

It's just that there are only certain positions

that you can exist in.

So there may be a fundamental lower limit to how small

we can go, or how small a time that we could possibly

experience or measure.

It just seems continuous from our very big perspective.

- [Speaker 18] What do we think when we

think of the smallest thing?

We think of it's the smallest thing that makes up everything.

Right now it's the subatomic particles

that we think of make up electrons

and protons and neutrons and make up the universe.

But there could be a whole new range of physics that's

contained in the smaller things that make up

those small things, which make up the electrons

and protons and neutrons.

- [Speaker 17] It's a very natural and human thing,

I think, to try and figure out what the smallest

little bit of something is.

You really want to find that smallest building block

that everything comes from.

And then once you've found that,

inevitably you break it down and you

find that something smaller.

At any moment in time, you've only ever managed

to divide the world up into a certain number

of small components.

And then you'll-- you'll hit a brick road.

But of course, that doesn't tell you

that you can't divide further.

It just tells you that where you are at the moment,

you can't divide further.

- [Narrator] Einstein's theory as to the composition

of the universe is what he termed Space Time Foam,

which is at the quantum level.

The theory predicts a foam-like structure,

which is the fundamental stuff of the universe.

- [Speaker 21] The smallest thing you can think of are

these tiny fluctuations of space time foam on the order

of a Planck length.

Now that's-- (BUZZES) it's really--

it's 10 to the -33 centimeters, so it's really tiny.

We can't see it with a microscope,

but that's what the numbers that we use in physics

say that, hey, there might be a smallest length,

and that's 10 to the -33 centimeters.

And at that length you have space time foam.

Instead of having normal space and normal time,

you have-- it's all curled up like this.

Space time foam.

- [Narrator] The idea of quantization is a solid idea,

but is it the right one?

It would seem to create more questions than answers.

A bit like the universe having an edge

or boundary if it were finite.

So the idea of infinity in both directions

is still a very real possibility for metaphysicians

who study this subject.

- [Speaker 9] Philosophers who were on this problem

are called metaphysicians.

And they asked the question, is there

structure all the way down?

We've discovered the Higgs Boson,

but it may be that the Higgs Boson is actually divisible,

and each part of the Higgs Boson

is divisible all the way down, that it just goes on and on.

It's very hard to contemplate on this idea

that there is structure all the way down.

It is a theoretical possibility,

and we just have to live with it as an open question.

(INTRIGUING MUSIC)

- [Narrator] We are still yet to discover if there is

a smallest unit of space time.

- [Speaker 19] So there is two different ways in which

the infinitely small comes up.

There's the-- the infinitely small in the sense

of the point, which has no length at all,

or the point in space which occupies no space at all.

And there's this puzzle that space is made up out

of things which take no space.

So what some people are inclined to say

is, wait a minute, this is very puzzling.

If each point in space occupies no space,

then infinitely many of them will also occupy no space,

so there can't be any space.

- [Narrator] One of the really strange things in our universe

is the paradox of the electron, which is thought

to have no spatial dimensions.

Is this possible?

Or have we just reached the limits

of our technology to measure such tiny particles?

- [Speaker 22] Within the theories that we have,

things like an electron have no spatial

extent at all of their own.

They-- they have an amount of mass,

but they don't actually take up any space.

(EXPLOSION)

- [Speaker 16] Every time we try to measure the size

of an electron, which you can do in various experiments,

the answer is it's smaller than we are

able to work out at this time.

And as far as we know, an electron is point-like.

Now, we've gotten this down to a very small scale,

but there's a long way to go from a small scale

down to absolutely nothing.

And people will continue to probe to see if there is

any structure in an electron.

It could be that going the other way,

we do end up with similar infinities,

in that an electron is something

that has no spatial size.

It is effectively a point, but we don't know at the moment.

Our experiments aren't good enough

to push us to those levels, and some people

think that there's an absolute limit to space itself,

that space itself is quantized on the very, very small scale.

If you keep dividing up and dividing up,

you'll eventually reach this point where you

can't divide space anymore.

And this is when you've reached one of the Planck scales,

as they're called.

But again, that's just an idea.

And it might be that space is infinitely divisible

and electrons are infinitely small.

At the moment, we just don't know.

- [Narrator] The fact that we don't know,

leaves any speculation as to what exists at these subatomic

levels with equal merit.

So anything is possible, and why not?

We have been astounded before at what

the cosmos has revealed to us.

(EXPLOSION)

- [Speaker 23] To me, there seems to be an inconsistency

between believing in the infinitely big,

but not believing in the infinitely small.

To me, that's a little fascinating.

- [Narrator] The fact is, we have no idea as to what

could exist at these infinitesimally

small scales and beyond.

- [Speaker 24] If you can go to the ultra massive and beyond,

which is infinity, and you go in the other direction

to the super small, you know, beyond the Planck length,

if you're able to scale down and you can find universes

beyond the Planck length, then everything's in reference

to us.

- [Speaker 4] I think that things can

go smaller and smaller until it turns into absolutely nothing.

So I think that something can get as small as it wants

until it's not there anymore.

- [Speaker 11] Our universe could be a tiny

speck on the forehead of, you know,

some other living individual.

Who knows?

You know, crazy stuff.

- [Speaker 23] What about if our whole universe is just

a very, very tiny glimpse of a breaking

of some conservation law in a much bigger scale of things?

Maybe where does quantum froth on a different reality?

- [Speaker 15] If I'm holding my hand up like this,

how many galaxies could possibly

exist in that tiny circle?

How many people, if there is such a thing

as other life forms?

- [Speaker 3] It's possible that there

are tiny worlds within our world,

many worlds within our world.

In fact, maybe our world is a speck

in someone else's much bigger world, um,

and we won't even know about that.

- [Speaker 25] How many things have we missed

over the thousands of years?

There are certain colors that we can't even see.

So I do believe there's probably tinier

things that we haven't discovered

that we don't even know exist.

(COSMIC HUMMING)

- [Speaker 8] It's awesome to speculate about what kinds

of things could happen on scales

that are completely different to our human experience.

Like, what happens if life exists

but a whole civilization can be born,

grow, fade, die in a second?

(ETHEREAL RESONANCE)

- [Narrator] The only scales that we can conceive of are

the scales relative to us.

Another interesting observation is the parallels

that we find between the huge distances between the stars

and planets to the huge distances between the nucleus

and electron within an atom.

- [Speaker 5] If you put the nucleus of an atom to scale

as a pinhead, the electron that surrounds

that hydrogen atom would be like a speck

of dust a kilometer away.

- [Speaker 13] Let's start by meeting a leading authority

on the subject, Dr. Atom.

Now, observing the professor himself,

we can see that his structure resembles

in many ways something almost as vast as the atom is small.

The solar system.

And there are certain similarities.

This is the center with electrons

in surrounding orbits.

- [Speaker 26] One of the extraordinary things I think

about examining something or looking at something from

a molecular or atomic level is that in reality, so much

of it is actually space.

I think it's fascinating the parallel in the pattern

between, for example, you've got the electrons going

around the neutrons, and in the sky

you've got the planets going around the stars.

And there is a kind of symmetry or synergy or something.

It is almost like space at a molecular level.

And yet most of what makes up an atom or molecule

is actually nothing is space, which is just like the universe

up there.

- [Speaker 10] Everything we see around us is

composed of atoms, and inside those atoms there's

protons, neutrons.

And if you zoom inside the protons and neutrons

with a very powerful microscope, which is called

an atom smasher, like the Large Hadron Collider,

you reveal that those are actually composed of quarks.

If you go inside that you are now

in the realm of speculation.

There's no evidence for what's beneath that layer.

- [Speaker 22] If there isn't anything fundamental,

is it possible that if you go down below, things get very,

very complicated again?

Because right now, what we do know

is that as we subdivide and subdivide and subdivide,

there are electrons and neutrinos,

and there are muons and taus and there

neutrinos, and then there are the equivalents in the quarks.

That's quite a lot of different particles,

but still it's a finite number.

We can catalog them and write down all their properties.

And then at some level, we're done.

Um, is it possible that you can subdivide those and make

more complicated things?

Well, the idea behind string theory

is you basically build those out

of vibrating bits of string.

But then why stop there?

Maybe you can build the strings out

of other things and those other things out of something else.

And maybe at some point you get such a rich set of interaction

that you actually get a scale below where things are actually

complicated and interesting, just

like the universe we have around us is

complicated and interesting.

There's stuff-- uh, you could end up with whole worlds

at micro levels.

Is that possible?

Of course, it's also logically possible.

- [Narrator] We just don't know what might be

revealed with our new technologies, like

the Large Hadron Collider.

But what are our best scientific theories to date?

- [Speaker 19] So no one knows what the scale of the universe

is at the smallest level.

You could go with the standard model,

and the standard model tells you that there are a fixed

number of particles, and the smallest of those particles

are in turn indivisible.

You could go with string theory,

which says that what's fundamental in the universe is

vibrating strings in either two-dimensional

or five-dimensional or 11-dimensional space,

whichever one you like.

And that's fundamental.

And there's no further subdivision.

And maybe those theories are right.

But, you know, I think you have to say the jury is out.

Um, one purely theoretical possibility that sometimes

philosophers-- most have called a gunk,

is the idea that the universe scales down infinitely,

and you never reach reached anything fundamental.

Maybe there's nothing fundamental.

Maybe it's particles within particles,

within particles within particles.

Or maybe it's, you know, underlying the strings there

a kind of something else.

And underlying them there is something else.

(DEEP SPACE HUMMING)

- [Narrator] The paradoxes of our universe don't make it easy

to understand things, such as an electron being larger than

the thing that contains it.

- [Speaker 21] In the past, our observable

universe was smaller than any golf ball an orange,

an electron even.

So if our observable universe was smaller than that, you say,

well, how in the world could an electron

exist inside of a universe that's

smaller than an electron?

That's the problem we run into at the small end,

and we don't know the answer, except we wave our hands

and say, we've got to have quantum mechanics here.

- [Speaker 18] So to say that just

because something is small, we know everything

about it is completely wrong.

That's what the Large Hadron Collider is doing.

That's what the scientists who work in particle physics

and are working at CERN are trying to do.

- [Speaker 10] There are a number of scientists who are

actively pursuing theories of even smaller scales,

just the unimaginably tiny scales within even the quark,

which is at this stage in what we call

the standard model of particle physics, is the building block.

This is the fundamental smaller scale.

I think we all have suspicions that there will

be a layer beneath that, and perhaps who knows

how many layers beneath that.

- [Speaker 18] We know mathematically

and physically how it works.

We can know that our universe goes

an infinite in every direction, but we know that's not the

end all.

There has to be a Big Bang.

(PRIMAL EXPLOSION)

So there has to be a finite point.

But that doesn't mean that finite point can't

be part of a larger framework.

It's a rubber band.

You could pull the rubber band more and more and more,

and it's still going to be connected on the same rubber

band, but you'll just be at different parts of that edge,

and our universe is great enough

that we can start to stretch that band

and start to pull it further and further away to test it.

But we're not nearly at all where

how far we can stretch it.

We have a lot of ways to go.

(EPIC MUSIC)

(UNIVERSAL BLAST)

(SOFT MUSIC)