All language subtitles for Infinity.What.On.Earth.Are.We.Thinking.S01E02.1080p.HEVC.x265-MeGusta[EZTVx.to]_track3_[eng]

(CAPTIVATING 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?

(MUSIC INTENSIFIES)

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.

How do we try and understand what may be simply

beyond human comprehension?

(EXPLOSION)

(GENTLE MUSIC)

How do we define the concept of infinity?

As we are finite beings, this seems

to defy our human limitations.

- [Speaker 1] That is such a hard question.

That is the--

- [Speaker 2] Well, that's a very difficult one.

(EXHALES DEEPLY, CHUCKLES) I was hoping

you weren't going to start with that one, because it's a--

you'd need-- I've got no answer to that, really.

- [Speaker 3] So when you say the word infinity--

let me think.

Don't even know how to answer that question.

- [Speaker 1] Infinity is a horrible concept.

It is mind blowing in the literal sense of the word.

To try to comprehend it, you really just crumble.

And certainly, I crumble.

- [Speaker 4] Infinity is everything and beyond.

Think of the largest or furthest thing

you can think of, and then go beyond that and beyond that

and beyond that, or in the other direction,

cut it in half, cut it in half, cut it in half infinitesimally.

You can never, never get to the end of it.

- [Speaker 5] In the Buddhist world,

we talk very much about infinite space

or infinite consciousness.

And, I still don't understand what that means,

but that, for me, has a real sense of possibility,

of opening, of spaciousness.

- [Speaker 6] In a way, defining something

goes against the very principles of infinity,

putting it in a box.

But at the same time, you need to be able to label

this concept of infinity.

- [Speaker 7] When I think of the word infinity,

I think of infinite combinations and possibilities

for existence and creation.

- [Speaker 8] The word infinity, it has a magical

quality, actually, I think.

People are always interested in infinity.

It brings up ideas of the meaning of life.

What is there after death?

Are things preordained, I suppose, in a way?

- [Speaker 9] Infinity is a quandary, a puzzle, an enigma.

I was told about infinity when I was a child.

And to be honest with you, to this day,

I've struggled with the notion of infinity.

It's a very, very hard to grapple with.

- [Speaker 10] When we say that the universe is infinite,

what we are actually saying is our measurement of the size

of the universe cannot actually be determined,

because we cannot reach the point, or the time,

or the volume or the energy where

there is a definite value.

- [Speaker 3] Well, infinity clearly exists as a concept.

We can think about it.

We can talk about it.

Whether the universe is infinite or whether there's

actually anything infinite in nature,

that's an open question.

- [Speaker 11] When I hear the word infinity, I think of space

stretching on forever.

And to the best of our knowledge, it does.

As far as we know, the universe is infinite.

There's no brick wall.

We don't see any evidence of brick wall.

And it ties in with the theory.

As far as we know, the universe just goes

on forever in all directions.

(WHIRRING, EXPLOSION)

- [Narrator] This is a TV show like no other.

It is the very origins of our universe.

It is the proof of an event that

happened a very long time ago.

You are seeing images created by the cosmic

microwave background.

This is the energy left over from the Big

Bang, which happened ago, and we can still see it today.

But what was the Big Bang?

The Big Bang theory is a theory based

on calculations that the universe

is currently expanding.

And using these calculations in reverse to determine the past,

it shows that our universe is about 13.7 billion years old.

At this time, all the matter of the universe

was concentrated into a tiny space the size of a grape,

with near-infinite density and incredible temperatures.

This grape-sized object contained all

the matter of the universe.

This then began to expand rapidly

to later form the stars and galaxies,

and is still expanding today.

From the Big Bang, it is thought that our four

dimensions were formed, three spatial dimensions,

and one of Time.

But how can we be sure that the Big Bang really happened?

- [Speaker 1] We see the afterglow of the Big Bang,

the cosmic microwave background.

We can see so many signatures that give us confidence

that this idea that the universe started off in a far

hotter, denser state than it is today,

and that ever since that moment has been expanding

and has been coming ever more dilute and cooler,

that is a measured statement of fact.

That is very much a history book of our universe,

and we have the images and understanding to show that.

- [Speaker 12] The Big Bang theory was something that

postulated a beginning and then an expansion, and then a what?

Is it a contraction back to a big crunch,

or is it an expanding universe forever?

(EXPLOSION)

(INTRIGUING MUSIC)

- [Narrator] One of the hardest things for humans to conceive

is the concept that the Big Bang was the creation

of everything that we know, that

from seemingly nothing, everything

that we know was created.

How can we understand something from nothing?

Or must there always have had to be something?

- [Speaker 13] There are so many things

now in the world, so many people,

so many different countries.

It's hard to believe that there was nothing because there's

now so many in the world.

How it's possible that it just pops up from nothing to this?

Yeah, it's hard to believe.

(MUSIC INTENSIFIES)

- [Speaker 4] I can't believe that the world

was created from nothing.

And if you think of it in terms of infinity,

infinity means there is no beginning or no end.

So there was no beginning is what you mean.

- [Speaker 14] How did the world just arise out

of virtually nothing, just out of a pinprick, you know,

such a huge world, such complexity,

out of, you know, nothing.

Wouldn't that violate the usual laws of conservation?

- [Narrator] The law of the conservation

of mass is a fundamental principle of physics.

According to this law, matter cannot be created or destroyed,

but only rearranged.

Fire is an example of this.

When wood is burnt, it turns mass into energy

in the form of heat.

So how did the Big Bang violate this fundamental principle

and create huge energies and matter from absolutely nothing?

- [Speaker 15] How did something come

into existence from nothing?

And what was there before the Big Bang?

You think of the Big Bang as generating the first moment,

and then there being moments after that,

and it seems like a very natural question to ask.

Well, how much time was there before the Big Bang happened?

Was there anything there?

Was there nothing there?

- [Speaker 11] Some people have a problem with the idea that

you can get something from nothing and this idea that

a Big Bang just spontaneously springs into existence,

and there was nothing before that.

They have a problem with that, as well they should.

We've got no way of imagining that process.

The human mind isn't capable of doing that.

And actually, in this case, even the maths has

a hard job with this as well.

And we really have the problem that, when you're talking

about the Big Bang, you really are up against the limits

of our science.

- [Speaker 16] We now think in terms of space time,

and our best science tells us that there was a starting

point to the space time.

(INTRIGUING MUSIC)

If that's true, then we know that the past is not eternal.

One thing we do know is that the dimensions that we're

talking about, both temporally and spatially,

are so enormous that we can hardly

conceive of the dimensions of the universe.

- [Speaker 11] The universe is expanding.

It came from this enormous explosion

about 13.8 billion years ago.

But as soon as you get very close to the Big Bang,

everything starts falling apart.

Our physics breaks down there.

We know it does.

And then if you ask the question, what happens

at the Big Bang or before the Big Bang,

you have to throw up your hands.

Our physics just doesn't go there.

We really don't have any idea.

But there's various ideas.

So one is that the Big Bang actually started from nothing.

There's no space and time before that.

There wasn't even a concept before

because there was no time.

And you get some quantum fluctuation

which seeds this universe.

I should stress, that's one theory.

And so when people say, what's before the Big Bang,

people ascribe to that theory and say, well,

that's a meaningless question.

That's like saying what's North of the North Pole or something,

because that's where the time started.

But not everybody subscribes to that.

And there's other models in which indeed there

was a pre-existing space and time,

and then you can quite reasonably say, well,

what triggered the Big Bang?

We still don't know, by the way.

It brings us no closer to an answer,

but at least you can then ask a sensible question.

- [Narrator] Quantum theory is the theoretical basis that

explains the nature and behavior of energy and matter

at subatomic levels.

It may be the answer to the very strange conditions that

created our universe, and how this immense universe was

created, seemingly from nothing.

- [Speaker 9] To understand how the universe

came into existence at all is the first fundamental problem.

And it all starts with understanding

something about what we call space, space

and time for that matter.

I suppose we thought up until the 1930s that space was empty.

It was nothingness.

But Einstein slowly taught us that space is not nothingness.

There's something to it, which can stretch and bend.

And so the Big Bang created space and time.

And that began to stretch and unfold.

And the way it came into existence

is all to do with the quantum world, the quantum universe.

- [Narrator] The quantum world is a world where things can

jump in and out of existence.

So could our universe be one of these quantum fluctuations?

Did our universe literally jump into existence

from absolutely nothing?

- [Speaker 17] That's the popular conception of the Big

Bang, that things started from literally nothing and created

the universe as we know it, but we know that that's, at best,

a caricature.

Now, why do we know that?

We know that because, really, that requires

us to extrapolate our laws of physics back to a time,

essentially time zero.

And that's the time when our understanding of quantum

mechanics and gravity need to be combined for the theory

to make sense, because that's the time

on which quantum mechanical effects

would matter for gravity.

And it turns out that that is a problem that's perplexed

physicists for about 100 years now,

really, since Einstein came up with his general theory

of relativity.

And the combination of that and quantum mechanics

has proved to be a very difficult nut to crack.

(DEEP WHIRRING)

- [Speaker 9] There's a concept called the Heisenberg

Uncertainty Principle.

And quite literally, out of nothing, you can get something.

You wait long enough, and because you can never

say with certainty where an object is in space or time,

you can say one or the other, but not both, what it allows

to happen is something to appear,

what they call a quantum fluctuation.

So you can have this nothingness.

And out of this nothingness you can get something, something

for nothing, for a certain amount of time,

as long as that amount of time obeys the Heisenberg's

Uncertainty Principle.

- [Speaker 18] So in terms of Einstein, there was

nothing before the Big Bang.

But when we bring quantum mechanics into play,

there's a real probability that our universe

wasn't born in the Big Bang, but actually

grew out of something else.

We don't yet have the mathematics, though,

to understand gravity and the other forces

in these huge densities to say what that was.

- [Narrator] The idea that all time and matter was,

at the time of the Big Bang, the size of a pea or grape

is a common perception.

But is this really the case, or is there more to this idea?

- [Speaker 19] Well, I can't believe that the universe used

to be the size of a pea, because the universe right

now goes forever and ever.

It's just hard to compare it to a tiny little vegetable.

- [Speaker 17] If you take all of the stuff that we can see

today and you ask, how big was it at 10 to the negative 34

seconds after the Big Bang, the answer to that

question is about a grape.

But that's not everything that there is.

That's just everything that we can see.

(INTRIGUING MUSIC)

- [Speaker 18] So if we take our universe as we know it now,

and if it is infinite in extent, if it goes to infinity,

you could travel forever and never

get to the edge, then it's always

been infinite from the start.

You cannot go from a finite universe

to an infinite universe.

You are infinite from the start.

What people talk about when they talk about the universe

being the size of a pea, what they mean

is the observable universe was the size of a pea.

All of the universe we can see around us today,

all the galaxies we can see.

They were in a volume the size of a pea,

and that pea was in a volume that would potentially

stretch to infinity.

- [Narrator] Our best theory to date is the Big Bang theory,

but this is a theory and only describes one event in possibly

billions of previous events.

We just don't know.

It is also a very unsatisfactory

concept to many, leaving only more questions than answers.

So if the Big Bang was not the beginning of time and space,

what existed before?

Perhaps another universe gave seed to our universe.

Perhaps the universe has always existed,

and the Big Bang was just an event

within our infinite universe.

Or perhaps another dimension or dimensions

were created, such as our theory of space

and one of time, and that dimension

contained our universe.

These theories are a lot more palatable than the "something

from nothing" concept.

- [Speaker 13] I'm not sure if I believe the Big Bang,

because maybe there was also before the Big Bang something,

and they also cannot prove that there was something.

- [Speaker 7] How can something come from nothing?

Like, to me, I find that much more perplexing than the idea

that things have always been there and infinitely changing

and infinitely expanding and infinitely multiplying

and infinitely diversifying.

- [Speaker 4] I don't know.

Maybe this world expands and expands and expands

and to the point that it then starts to contract

to the extent that it can come through this tiny hole

and explode out the other side.

(DEEP

WHIRRING) (EXPLOSION)

- [Speaker 7] I think the Big Bang was a sequence

in an infinitely changing universe,

multiverse, galaxy, world, Earth,

just one big constant flow.

(EXPLOSION)

- [Speaker 19] I have real trouble understanding

how you could have nothing and then suddenly have something.

So to my mind, a logical conclusion, but not scientific,

is that something has always existed.

So that sort argues that there has always been something,

and I even know what something is,

but something that allows the laws of physics to merge,

and that must have always existed in the past

and presumably will always exist into the future.

(INTRIGUING MUSIC)

- [Speaker 15] There are lots of models according to which

the Big Bang was, in some sense, the first

moment of this universe.

But that doesn't mean that there

wasn't something before that.

So maybe there was the end of some other universe,

which, at its end then generated this next universe.

- [Speaker 11] It's very difficult to describe

or work with a universe which starts

out of nothing whatsoever.

We don't have the mathematical or physical tools

to describe that.

And so many of us prefer models where a Big Bang

starts in a pre-existing universe,

or there's something before it.

There's a pre-existing time.

It's much easier to comprehend.

It's much easier to work with.

(DEEP WHIRRING)

- [Speaker 1] To postulate about what came before,

I don't even have the tools to ask the question.

The physics breaks down.

The guiding principles and those theories,

they can't help anymore at that point.

Now, maybe some absolute gun will in the future

understand this and come up with a theory of everything

that reconciles these seeming impossibilities, the emergence

of everything we see from nothing, or even

the creation of time itself.

But right now, our theories just

don't give us a tool to ask the question

of what came at time zero.

And I simply can't conceive of nothing.

It is physically impossible to imagine, as it is,

to conceive of an infinite of something.

(INTRIGUING MUSIC)

- [Narrator] There is now an alternative theory that the Big

Bang was in fact, many big bangs,

that the Big Bang was simply everywhere at once,

and there was no one location.

This is, of course, as hard a concept

to understand as the original Big Bang theory.

How do we begin to understand such concepts?

- [Speaker 17] So one possible way that we can have the Big

Bang that we know and love and actually can Measure

is that really what happens is there

are a lot of little bangs.

Little bangs are still vast and create entire universes

like our own, but they're little in the sense that really

what there's a much larger universe

out of which little bangs happen

for quantum mechanical random reasons every so often.

And it doesn't have to be very often indeed.

It can be pretty random and pretty rare, but just

often enough that it happens.

And once it happens, you could have a universe

that is mostly very boring.

But every so often, in perhaps even more dimensions

than just our three spatial dimensions,

you have a bang happening.

And maybe that bang is always very similar.

Or maybe sometimes it even creates a universe

with different laws of physics.

So bangs happen.

Sometimes they may create a universe

that looks like our own, with protons and neutrons

and three dimensions.

Sometimes it may create universes

with only Higgs bosons and six dimensions, and maybe things

in between that we can't even describe.

So every time this happens, we could get a new universe

inflating out of this background

and then making something that could last forever,

or maybe only last for a finite amount of time

and then collapse in on itself.

But this way, you can have things

which locally look finite.

So they had a beginning, but in fact, overall,

things could be infinitely large

and infinitely long lasting.

So that's one way that you can have both Big Bang or big bangs

and infinity, and you can still have things coming

into existence, not really out of nothing,

but just out of something else than what we see here.

(EXPLOSION)

- [Narrator] The Big Bang theory is a solid scientific

theory of what it describes, but it is now understood to be

very lacking in detail and may be only

part of a multifaceted event.

This theory is perhaps only the beginning of our understanding.

- [Speaker 10] Mathematically and physically,

we cannot actually determine what the Big Bang was.

We can physically calculate our universe right after the Big

Bang, but that last fraction of a fraction of a second

we can never do, because we don't actually have

a tool that can do it yet.

(DEEP WHIRRING)

So when we try and go to measure or calculate

or explain what the Big Bang was, we need space and time.

But the Big Bang was the beginning of space and time.

So we're trying to explain something that created

something that the tools that we're using

are reliant on to explain the thing

that we're trying to measure.

So you get chasing your tail.

So the philosophical view here is that we're not

able to ever calculate or measure or determine what

the Big Bang was, because we don't have a way

to describe the universe without using

the stuff in the universe.

(INTRIGUING MUSIC)

- [Narrator] Trying to discover what the Big Bang actually

was seems as elusive as ever.

How do we move forward to try and find the answers?

- [Speaker 20] So if we take the equations of the universe,

we can run the universe back to this time,

10 to the minus 40 seconds after the Big Bang,

when everything we know in the universe was down,

and something, for example, the size of a golf ball.

We believe at that point that physics is essentially just

in a form where the laws of quantum mechanics,

as we know today, are still working.

We know that quantum fluctuations where things come

in and out of existence will create gravitational waves,

and that we have a chance if those fluctuations are

big enough, of detecting them in the cosmic

microwave background.

Now, there's a lot of physics that we're

extrapolating through.

And so the hope is that when we see those fluctuations,

we'll be able to understand everything that's happening

at those energies above where the Large Hadron Collider can

essentially probe here on Earth,

and where we get to right after the time of the Big Bang.

- [Speaker 3] We have some theories now

that can potentially explain what could

have seeded the Big Bang.

Quantum physics, for example, says

that if you take everything out of space,

you turn it just into a complete vacuum,

so you take all the particles out,

you take the light out so that there's nothing left,

nevertheless, you're left with this,

like, quantum foam, this seething froth

of virtual particles that are popping in and out of existence

all the time.

And this is just the nature of the vacuum itself.

And it could be that our universe

was born from that kind of quantum foam.

So that's what was likely to be before the Big Bang.

(SWIRLING, EXPLOSION)

- [Narrator] One of the dimensions that was created

in the Big Bang was time.

Time is one of our four dimensions, three in space

and one of time.

(INTRIGUING MUSIC)

Time is the least understood dimension, seemingly

born in the Big Bang.

What is this strange dimension?

It has no mass or physicality and is as

intangible as we can imagine.

Time is particularly important to humans as everything we do

is ruled by time.

Our lives are measured in a finite number of years, a day,

in a finite number of hours.

Our lives last a fraction of time

compared to the age of the universe.

Could time be something exclusive to our universe,

or is it part of the fabric of everything that is?

- [Speaker 21] I actually think that

time is a man-made concept.

So in essence, it doesn't go on forever and ever, ever.

And it does.

It simply is.

- [Speaker 2] I've read this theory that at the moment

of the Big Bang, there were four dimensions, but there

were four spatial dimensions.

And as the Big Bang progressed, one of those spatial dimensions

turned into a time dimension.

So as you get closer and closer to the Big Bang,

the idea of time makes less and less sense.

As you get closer and closer to that moment of the Big Bang

that moments ceasefire to exist.

(EXPLOSION)

- [Speaker 15] If the Big Bang really was the thing that

generated, ultimately, space time,

then there's no sense in which there was nothing prior to it.

There's no sense in which there were moments prior to it.

There was no place for nothing to be,

and there was no time for nothing to be in.

- [Speaker 22] The Big Bang defines the beginning of time.

So you can't ask what was before it

because there's no time.

Now, that's not to say that we can't come up

with some sort of structure according to which the Big

Bang is nested in some larger structure in which

there are multiple big bangs.

But the interesting thing about them

is that it's not that there's anything before the Big Bang.

Before makes no sense.

There is something else, and that something else

may be connected to the Big Bang some way.

But the connection is not through time,

because time as we know it is something about this universe.

- [Narrator] Although this is our current understanding,

is it possible that time has existed in some form or another

before the Big Bang?

- [Speaker 16] There seems to be a natural tendency

for symmetry, so if we think about time,

we can think that there's an infinite

past and an infinite future.

- [Narrator] Does this tendency toward symmetry suggest that

time has always existed, and will

always exist into the future?

- [Speaker 10] We think of time as a one directional, one

dimensional, one-way street.

And we think of space as, oh, you

can move in every direction, you can go up

and you can go down.

You can do whatever you want.

You have complete freedom.

And this is inherently tied in this issue where time seems

to be the seconds go by hours, days, years, that we're always

seemingly going forward in time because that's

how we measure time.

But really, time is no different

than the spatial dimensions.

- [Speaker 20] So time is a particularly

complicated construct.

That is one where physics does indicate it is possible to have

space without time, it's possible for time

to maybe not have existed in the past.

There still would have been something,

it just may not have involved time as we know it right now.

- [Speaker 10] If our universe does have an end,

that will end time in our universe,

so therefore, it will end space and it will end everything.

What that means, we don't know yet.

- [Narrator] If time ends, does that

mean infinity cannot exist?

And could our universe's past be the same as our future?

- [Speaker 1] Tomorrow doesn't look like today,

and it definitely doesn't look like it did yesterday,

or at least, 13.6 billion years ago.

The universe had a very different beginning,

and it will have a very different end.

- [Speaker 23] So time in the past is bounded by a big bang

where we have space time foam, and there's no

time earlier than that.

At least, that's the standard model.

What about the future?

Well, the universe is expanding.

Will it ever stop expanding?

What will happen in the far future?

Well, the stars will all burn out.

Everything will fall into a black holes.

The black holes will evaporate.

You'll get all kinds of radiation.

And this radiation will get longer and longer and longer.

And then you will be in what's called

a state of maximum entropy.

Now maximum entropy, nothing happens.

And if there are no gradients, no structure, no tables,

no suns no watches, no anything.

And that means you won't be able to measure time.

So in one case, time goes on forever without an end,

infinite in the far future.

On the other is, well, wait a minute.

Once I run out of the ability to measure it,

what am I talking about?

And so there it kind of peters out as we lose

the ability to measure it.

(INTRIGUING MUSIC)

- [Narrator] Einstein came up with an even

more mind-blowing theory, born out

of his theory of relativity.

It is the block universe theory.

In the block universe theory, time and space

are embedded in a block-type structure where there is

no difference between the past and the future,

and we are all spread out in time.

The passing of time is purely a mental construct.

- [Speaker 15] A view of time that

began with Einstein is that our whole world is one giant block.

So people often call this the block universe view,

and it's the view according to which the past, the present,

and the future are all there.

It's one big block of space time.

And there are relations between time.

So there's earlier times and later times,

but there's no sense in which the past times are there,

but the future times aren't.

Everything is just out there, and you

and I happen to be located at a particular point in the block.

The dinosaurs are located at a particular point in the block.

There are also all of the future moments located.

So if it turns out that there are going to be really super

intelligent robots at some point,

they're also out there already in space time,

doing super intelligent, roboty kinds of things.

(ELECTRONIC BEEPING, WHIRRING)

- [Narrator] The block universe theory has recently come

up against much skepticism.

But what structure, if any, does time take?

- [Speaker 15] Whether time is infinite or finite,

we can still ask interesting questions about

what sort of structure it has.

So most of us probably assume that time is linear.

At least, that's how we probably imagine it.

We think of the past as being sort

of back along a line, and we of the future

as being forward along a line.

And we conceptualize time as being a little bit

like a ruler, and we find ourselves

somewhere along that ruler.

But of course, there's lots of different ways

that time could be.

Time could be branching.

Could be that time is actually this massive kind

of tree with many branches.

Or it could be that time is a loop.

So it could be, for instance, that

in some sense, what you think of as the very

first moment is also at the very same

time, the very last moment.

So if you think about time as being a loop,

if the very first moment is at the same time, the very

last moment, then since the very first moment

has in some sense happened, then the very last moment

has also happened.

And so you might think this seems like a very dismal view

of the world because it seems as

though everything that's future is both future and past.

So if the past is fixed, then the future must also be fixed.

And so there's no sense in which we can make things other

than they're going to be, because the future just

is the past from a different direction.

(INTRIGUING MUSIC)

- [Narrator] Time remains to be a very hard-to-grasp dimension,

and being finite makes this an even harder concept to fathom.

But is it possible to move around within this loop

or block of time?

One way we know of actually happens every time

we look into the night sky.

- [Speaker 22] When you're looking up into the stars,

you're looking into the distant past.

And of course, you know, the nearby stars,

you're seeing them as they were three, four years ago.

The faraway stars in this galaxy,

You're seeing them as they were many thousands of years ago.

Other galaxies.

You're seeing them as they were a long, long, long time ago.

And if I get a telescope-- and I

used to play with telescopes a little bit when I was a kid--

and you look at the really, really faint stuff,

you're seeing stuff that goes back almost

to the beginning of time.

So when I look up into the stars,

I think people talk about time machines.

We've got one.

Just look up into the stars and you're

seeing the past, the distant past.

And I'm wondering, are there people there?

Am I seeing stars or that have planets on which

there are people up there?

And if they're not there, as I see them, are there now?

- [Narrator] So perhaps our perceived linear progression

of time is in fact malleable.

And one day we might discover a way

to navigate through this elusive

dimension, as we do freely in the other three

dimensions of space.

(CLOCK TICKING)

- [Speaker 10] We just don't know

how to treat time properly.

It's been the unwanted stepchild of physics,

I think, in terms of our everyday thinking.

And if we actually properly think about it

and appreciate it, then I think we'll

grow to accept all the consequences it means,

including infinity.

(THEME MUSIC)