Human Universe (2014–…): Season 1, Episode 2 - Why Are We Here? - full transcript

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Each one of us is made
from mere matter...

..yet we are matter
with curiosity,

we ask questions.

And, in the private world
of our minds,

one particular question burns...

Why are we here?

A scientific answer to this question

may not be far away.

MAN CHANTS

If the existence of any one of us
is singled out

the answer to the question
"Why are we here?"



looks like pure chance.

Like any particular individual,

baby Shurik was born into this world
as the culmination

of a chain
of apparent coincidences.

A chain so long that,
at first sight,

it looks highly improbable.

The chance that a particular sperm
reached a particular egg...

The chance that baby Shurik's
parents happened to meet...

and their parents too...

and generations of ancestors
before that.

But don't stop there.

The apparent coincidences go back
much further than that...

..to our planet
and its position in space.

We appear to live on a perfect
planet in a perfect universe.



It feels as if it's been made
for us.

The Earth orbits at just the right
distance around just the right star

for the temperatures on its surface
to be just right

to permit liquid water to exist.

And those temperatures have remained
just right for four billion years,

which is just the right amount
of time for us to have evolved.

And this seeming luck
continues beyond our solar system.

We live in a universe that's
expanding at just the right rate

for stars and galaxies to form.

And within those stars, the forces
of nature are just

the right strength to allow them to
assemble the elements of life,

carbon, oxygen and iron,
in their cores.

If you trace it right back,

the odds of YOU existing in this
universe don't just look small,

they seem almost
infinitesimally small.

Why are we here?

Is our existence merely accidental?

And if we are just happy accidents,

then what about the universe?

Is its form, its nature,
its very existence

also accidental?

And if that's the case,
what does it mean to you?

Well, I think modern science is very
close to answering these questions

and, in this film,
I want to tell you why I think that.

WIND HOWLS

Shankar is 12 years old

and has lived at this school
since he was eight.

He sees his parents only every
three months...

But, to him, it's worth it

because he has a singular life
ahead of him

as a Hindu priest, or Brahman.

Shankar is one of 40 students here,

all of them
training for the Hindu priesthood.

CHATTER AND LAUGHTER

Their day follows a strict routine
starting at 5am.

BELL CHIMES

CHANTING

Almost every day the students chant
between seven in the morning

and seven at night.

They're chanting Vedas,
ancient verses which date back

4,000 years, containing
the poetry and myths

on which Hinduism is based.

BELL CHIMES

These religious verses hold
some unexpected thoughts.

They contain the concept of zero

and they touch on the notion
of infinity.

And they use mathematical concepts
such as Pi, square roots

and Pythagoras' theorem.

And, in one part of the Rig Veda
learned by the older boys,

you can find a very
interesting thought.

It addresses a crucial question

about the formation of the universe.

"The gods are later than creation."

I think that's
a remarkable sentence.

It displays real intellectual
rigour and honesty.

It's obviously not a sufficiently
good answer to say,

"Well, all this exists
because it was willed into existence

"merely by some kind of deity."

It's reasonable to then ask
the question,

"Well, what's the origin of
the deity?

"Has the deity existed forever,
has the universe existed forever?"

So, I think, just seeing
signs of that...

that kind of thinking which is
really what you might say

the prerequisite or the first signs
of a scientific way of thinking.

The scientific approach acknowledges
that if we're ever going to ask

grand questions like
"Why are we here?"

we have to begin with "how".

In my view science
is a...a humble pursuit.

It starts by asking very simple
questions, asks questions like,

"Why is it that when you let
something go

"it falls to the ground?"

You let it go, it falls to
the ground again,

falls to the ground again,
you observe regularities in nature,

tiny, small regularities,

and try and explain them
and model them, understand them.

Through that process
we've been led to

an intellectual framework
that maybe allows us

to answer questions about the very
origin of reality itself.

From the marketplace
to outer space,

those regularities in nature can be
found almost everywhere you look.

Galileo said nature is a book

written in the language
of mathematics.

And, the more you start
to look for that language,

the more you see it...

..everywhere.

Rivers meander through the landscape
in a seemingly random way

and if you just look at a few turns

then they will be random.

The river might change its course

because of some geology,
a big rock formation.

But if you look at a river
over a large length,

say tens or hundreds of kilometres,

then you see that the meanders
aren't quite random,

a pattern emerges,
there's order there.

This is the satellite picture
of the bend in the river,

the meander you can see here,

and the mathematical relationship,

the pattern that we're
looking for, is this.

If I measure the wavelength
of the meander,

which is just the length
between the point

where the river starts to turn

and meanders up and then
meanders down and comes back again,

you see it's around
11 centimetres on this map.

And then if I measure the width
of the river at this point

then it's something
like one centimetre,

so the ratio of the wave length

of the meander to the width of the
river, in this case, is about 11.

Now, the interesting thing is that
if you take this whole river,

so not just one bend
but hundreds of bends,

you'll find that that ratio
is always somewhere

between about 10 and 14.

What's very interesting is
it's not just this river,

this isn't a special river.

If you look at any river
on the planet,

no matter how small or wide,

you'll find that it's always
somewhere between 10 and 14.

There's obviously some
pattern there,

it reflects something fundamental
about the way that fluids

flow across the surface
of Planet Earth.

And this rule can even be
seen on other planets.

On Mars, the rivers have long
since dried up,

but the arid river beds show
the same meandering pattern.

And on Titan, the largest moon
of the planet Saturn,

the rivers are made of methane
cutting through a bedrock of ice.

But even here the same ratio
appears to exist.

This rule seems to hold true
for every river

found across the solar system.

Order is hidden in everything,
from rivers, rocks and landscapes

to living things,

even the most exotic
and elusive of creatures.

"In the days when everybody started
fair, Best Beloved,

"the Leopard lived in a place
called the High Veldt.

"The Giraffe and the Zebra
and the Eland and the Koodoo

"and the Hartebeest lived there,

"but the Leopard,
he was the 'sclusivest

"sandiest-yellowish-brownest
of them all."

Rudyard Kipling's Just So story,
How The Leopard Got Its Spots,

tells the story of an Ethiopian man
who was the Leopard's friend,

he used to go hunting
with the Leopard.

And one day he noticed that
the Leopard wasn't being

very successful, it had a plain,
sandy coat,

whereas all the other animals
had camouflage.

He said, "That's a trick worth
learning, Leopard."

So he took his fingers and his thumb
and he pressed

into the Leopard's coat to give it
that distinctive

five-pointed camouflage pattern.

So, in the absence of an Ethiopian
hunter present at the birth

of every leopard, how did
the leopard get its spots?

No-one disputes the reason
why leopards have spots,

they evolved as camouflage.

What's less obvious is how
the pattern appears on their coats.

(WHISPERS) Oh, there, yeah, yeah.

Let's have a look.

Fantastic.

He's ducked down into a little...
little valley.

It's really interesting, the moment
you lose sight of the leopard

then you turn round to see it again,

it's very, very difficult
to find it.

You've essentially got to wait
till it moves.

It just shows you
the effectiveness of camouflage.

How does that complex camouflage
emerge from the millions

of separate cells
across the leopard's skin?

Measure out...

..a precise amount of indicator.

Then I'm just going to add it in.

It turns out that complex patterns
can emerge

from simple ingredients.

And, mix them up.

Now, if I pour this
into this Petri dish...

There, you see?

And now can you see the colour
coming back,

fading back in?

It's not the usual chemical
reaction,

you mix two things together, you get
a big bang or a cloud of blue smoke,

which is what all chemists love.

This reaction is continually
oscillating

backwards and forwards.

So we started with the simplest
of ingredients,

mixed them together

and they reacted in such a way

that complexity,

that pattern, emerged
from the underlying simplicity.

A similar process
happens in living things.

When the leopard
was still an embryo,

it's thought that two competing
chemicals, washing over the skin,

created the distinctive spots.

So if you have a sandy background,

then you can imagine
one of these chemicals

that causes or stimulates
pigment to appear,

so as it grows you get a dark spot.

Where it's inhibited and drops
you return to the sandy background.

It grows again, you get a dark spot

and returns to the sandy background.

The same principle is believed to
create the stripes of the tiger,

the zebra and the sea snail,
to name just a few.

Scientists get very excited

when they discover
an explanation like this

because it means we've understood
something much deeper about nature

and that's that complexity masks
an underlying simplicity.

All the intricacy that we
see across the natural world

emerges from a few simple laws.

The meander of a river
and a leopard's spots

are just two examples
of patterns in nature,

but there are countless more.

By looking carefully
at the patterns in nature

and trying to understand
their origin,

that's what Copernicus and Kepler

and Newton and Einstein and Galileo

and Curie and Dirac and Feynman and
a thousand others have discovered.

There are regularities in nature,

there are patterns as far
as the eye can see,

on every scale from atoms
to galaxies

and those patterns are a reflection
of the simplicity and beauty

of the underlying laws of nature.

A blueprint for creation does exist,

a scientific one.

But how do the laws of physics
explain the existence

of human beings?

How, or why, did atoms come together
to form us in particular?

The game of cricket is
unfathomable to some

but to those who understand it
it's bewitching.

I really love it,
I just can't express it...

I...I don't express it in words.

My dream is to play for India.

This is what I've been aiming for
since my childhood.

Today Subitu Bose and his team-mates

are playing against rivals
Neerja Modi School.

Cricket is based on a set of rules

and they haven't altered
significantly since the 1800s.

CHEERING

But, despite the existence
of these rules,

no match is ever predictable.

Take, for instance, the ball.

Climate makes a big difference
to its swing,

dew picked up from wet grass

or scuffing from dry ground...

..not to mention how it's bowled.

And then there's the bat.

Each batsman has a preference
for a bat of a particular weight

and that will affect his stroke.

Not forgetting the temperament
of each player,

the mood of the umpire

and the mood of the crowd.

When you get so many variables,
the number of possibilities

becomes enormous
and yet all this complexity

emerged from a set of fixed rules.

A game of cricket is played out
according to a set of simple laws

and so it is for the universe,

and here are the laws
of the universe.

This is the standard model of
particle physics

and this is Einstein's General
Theory of Relativity

and you can fit them
easily on a scorecard.

And here are the laws of cricket

and it has to be said,
at least in this notation,

that cricket is more complicated
than the universe.

But even given these simple laws,

the number of ways that both games
can play out

is effectively infinite.

So the laws do not make
the outcome predictable.

But all we really
care about is the outcome.

In the case of the game
of cricket - who won?

In the case of the game
of the universe - we exist.

And for the cricket match,

the result could have turned
on the tiniest,

most insignificant little event,

the way the ball gripped the pitch
and deflected off

a couple of blades of grass,
clipped the edge of the bat

and was caught
by the wicketkeeper.

And it's the same for the universe.

Some collision of two dust particles
ten billion years ago

could have led to a chain of
seemingly insignificant,

infinitesimally unlikely
little events

that led to something that we care
deeply about.

Our existence.

Today the way the game of cricket
played out

had an undesired outcome for Bose.

The fielder caught my, er...

caught the ball here.

Had I have hit the ball
a little to the...

to his left or right, it would
have gone to the boundary.

But, sadly, it went straight
to the fielder.

I was like, "Ahh...

"What have I done?"

Just like a game of cricket,

the way the universe played out
to create us humans

was not determined
by the rules alone.

Chance played a part, too.

This temple's over
a thousand years old,

it's dedicated to
Lord Shiva the Destroyer

and it's built
in the Tantric tradition,

which is at least in part
a celebration of pleasure.

But whilst I find some of these
suggestions instructive,

that's not why we're here.

We're here because of the location
of this temple.

Because this temple is in the centre
of a crater, three kilometres wide.

Geologists are still debating
what made it

but it could well be
the scar left by a meteorite

smashing into the Earth.

Throughout its lifetime
the Earth has been

constantly bombarded by objects
from space.

Think about one particular
collision,

the impact that probably wiped out
the dinosaurs 66 million years ago,

and think about the history,

the lifetime of that rock
that smashed into the Earth.

Imagine one particular day
in the lifetime of that rock,

on one orbit, perhaps billions
of years ago,

when another rock,
no bigger than that,

instead of missing it, hit it,

smashed into it and changed
its orbit very, very slightly.

And, over millions and
millions of orbits, that change

would have got amplified,
until, perhaps, that day,

66 million years ago, instead
of smashing into the Earth,

the dinosaurs were looking up
at the sky

and they saw a fireball
blaze across the sky

and miss rather than hit.

That would have changed history.

In all probability the dinosaurs
would still be roaming

the surface of the Earth today
and we probably wouldn't exist.

But the rock DID strike,
the dinosaurs WERE wiped out,

and purely by chance our human
existence became possible.

And fateful accidents of equal
importance for our existence

have also happened on a much
smaller scale.

CAMEL GRUNTS

In Pushkar they have quite
a tradition of camel racing.

BRIAN CHUCKLES

There's a saying, apparently,

which is the camel
and its driver go their own way...

..and there's the proof.

Despite that, there's a surprising
similarity between camels and us.

Now what I'm going to do is I'm
going to take a sample of my cells

and a sample of the camel's cells.

What's his name? Rapi. Rapi.

Rapi? Yeah. Right.

So to take my cell sample
is quite easy.

I just have to...

..rub that on the corner
of my cheek

so there are my cheek cells
on there.

I'm going to do the same now
to Rapi, but could you hold him,

hold his mouth open?

CAMEL GRUNTS

Actually, you know what,
can I ask you to come?

There's no way I'm going in there!

Can you just rub that on his cheek?

That...that's going to be
enough, that's plenty.

That's plenty, yeah, and then
hand it over there.

There we go!

Right, thank you, thank you.

I apologise.

So now we've got a...
a sample of Rapi's cells

and a sample of my cells

and we'll make a comparison.

I apologise again.

So this is the slide
of my cheek cell.

You see there it's stained blue.

Quite small, but I can see
detail inside it.

And this is a slide
of the camel's cheek cells.

And the most obvious thing to say
is they look identical,

impossible to tell them apart,

and that's because for all intents
and purposes they are identical

and that's because myself and
the camels over there are mammals.

But...

if you look more closely,

then you see that the cells have

many structures inside them.

The most obvious feature
is the nucleus,

where most of our DNA is stored.

But you can also see
hundreds of little dots.

Many of these structures
are called mitochondria.

These are the power stations
found in the cells

of every complex living thing.

And, yet, once upon a time these
essential structures

were separate,
free-living creatures.

A long time ago,
two or three billion years ago,

the Earth was populated
only by single-celled organisms,

two great kingdoms of life,
the bacteria and the archaea,

and, it has to be said,
things were pretty dull,

there was nothing that we might call
complex and, in fact,

very little happened.

Those two single-celled things
just stayed the same

for billions of years.

But then one day, quite by accident,
everything changed.

What many biologists believe to have
happened is that a bacterium

got inside an archaean
and for some reason wasn't digested.

Instead, a symbiotic
relationship began.

The bacterium may have been
protected by the archaean

while the archaean got access to the
energy generated by the bacterium.

Once that cell had access to
the vast amounts of energy,

the potential that the
internal bacterium gave it,

then basically all hell broke loose.

And that energy allowed the cell to
begin to work in larger colonies,

to begin to build complex
living things.

So the mitochondria in your cells
today are the descendants

of that chance collision
billions of years ago.

That singular event,
that fateful encounter,

was purely accidental, but the cells
that it produced had such

a survival advantage,
the energy made available to them

by the mitochondria, that its effect
was amplified beyond imagination

by natural selection, which is not
accidental and it is non-random.

So it's the interaction
between accident and rules,

chance heavily constrained
in the framework of natural laws,

that led to the evolution
of humans here on the Earth.

In our universe there was
no particular aim,

no intention for us humans to exist.

Instead the life of the universe
is just like a game of cricket...

..where rules
and chance play out together...

..and quite by accident happen to
produce a human universe.

Over the course of centuries
we've worked to find

the combination of rules and
accidents that made today's world.

We now understand the laws of nature
so well

that we have at least a reasonable
scientific understanding

of every step in that chain,
from the present day

to the first few moments after
the Big Bang, and that is a
tremendous achievement,

it's the great achievement
of modern science.

But just as the origin of the
gods themselves is

questioned in the ancient
Hindu hymns and the Rigveda then

so we are faced with a question,
a very profound question -

who wrote the rules of the game,

what is the origin of
the laws of nature?

What is the origin
of the universe itself?

What went before the Big Bang?

It's a question that takes us
to another world entirely.

A samurai sword is both sharp
and strong.

Able to cut a body in half...

..but precise enough to slice
through a single hair.

Gassan Sadatoshi is
a master sword maker.

His family have been making swords
for over 800 years.

The first stage is to reduce the
carbon content of the raw material.

If there's too little carbon
it'll be soft,

but too much and it'll be brittle.

This is all a remarkably
high-precision process,

everything that they're doing
matters to make the perfect sword.

And even the force
with which they hammer down matters,

that helps set the precise
mixture of ingredients,

and they're aiming for precisely
0.7% carbon in that steel.

Repeated heating and layering mixes
the iron and carbon

so the block is uniform.

This process can take weeks.

The final stage is to harden
the cutting edge of the sword,

a process called quenching.

In the case of a Japanese sword, if
you get all the ingredients right,

the precise mixture
of iron and carbon,

if you get the temperature right,
you get the hammering right,

everything right, over a year,
then you get the perfect sword.

Now, in the case of the universe
the ingredients aren't things

like iron and carbon, of course, the
ingredients are a set of numbers,

they're called constants of nature,
they're things like the strength

of gravity, the speed of light
and the masses of the particles.

And they also require precision.

They have to be set in just
the right way

if you want a universe
that supports life.

In the same way that
a samurai sword would be weakened

if the ingredients were different,
the universe might be unable

to support life if the constants
of nature were somehow altered.

Now, if I was some all-powerful
deity, which arguably I'm not,

then I could imagine varying
all those constants of nature

to see what happened.

I could imagine some great big
control board with little
knobs on it.

One of them changes the strength
of gravity, the next one changes

the mass of the electron, the next
one changes the speed of light.

And the question is how much
freedom do I have

if I want living things to exist?

The answer is, not very much
freedom at all.

If at the Big Bang the strength
of gravity were increased

then the universe would have
collapsed in on itself

before life had time to evolve.

But if the strength of gravity were
decreased then galaxies

wouldn't form, so there'd be
no planets, no stars and no life.

If you decrease the speed of light
by just a few percent

our universe would have
no carbon in it.

Increase it by about the same amount

and our universe would have
no oxygen.

Because we have no idea why
the constants are the values
that they are

then we're presented
with something of a mystery, because
you can ask the question,

well, if it's just random, if indeed
the universe began and somehow

these random numbers got chosen,
then how lucky are we that we exist?

How lucky are we that we live in a
universe where those constants

are just right to allow
galaxies to from and stars to shine

and elements like carbon to form
in the hearts of stars?

So what could account for
the uncanny precision of this
set of numbers?

Hello, can I have just one? Yeah.

Thank you.

You know, our universe, with
all its beautiful laws of nature

and its finely tuned constants,
feels incredibly lucky.

I mean, it's like buying a lottery
ticket and winning the lottery,

but it's stranger than that,
because it's like winning

the lottery in which only one ticket
was ever printed.

But that's of course not how
a lottery works.

Yes, it is extremely unlikely that
I'll win the lottery

with this ticket, but there
are millions of tickets printed

so it's not surprising at all
that someone wins it.

So could we think of our universe
in the same way as the lottery?

The reason that we appear to
live in a perfect universe with

the perfect numbers,
the perfect constants of nature,

the perfect laws, is because there
are in fact countless millions,

perhaps an infinite number
of universes, each with different

physical laws, different numbers,
different constants of nature.

Then we shouldn't be so surprised to
live in the perfect universe.

It's like the lottery - somebody's
got to get the right ticket,

somebody's got to win it.

Just as the lottery has many
tickets,

each bearing different numbers...

..so there may be many universes,

each with different values for
the constants of nature.

Universes with stronger or weaker
gravity,

slower light or faster light.

Now, that might make sense
mathematically

but is it really
a sensible suggestion,

an infinite number of universes?

What does that mean for reality?

Miyake Jima island.

3,000 people live here,
making a living from the sea.

But it's a precarious
place to call home.

Because this entire island is
an active volcano.

Occasionally it belches forth
scorching lava that

incinerates anything that
stands in its way.

Until an eruption in 1983,
this was the island's school.

But volcanism doesn't just destroy,
it also creates.

Around 30,000 years ago this
whole island emerged

from the vast emptiness of
the North Pacific Ocean.

And it's not just this island, it's
the whole of the Izu Archipelago

and much of Japan.

All of these islands have risen up

out of the ocean,
seemingly from nothing.

And it's even happening right now.

This island, called Nishinoshima,
has been growing steadily

since it suddenly
appeared in November 2013.

If we didn't know better, we might
ascribe that creation

to the act of the gods,
but we do know better

because we know about geology,
we've done some science,

so we know that the origin of
this island is volcanism.

It comes from the inner heat of the
Earth, which is itself a leftover

from the history of its formation
4½ billion years ago.

So we have a mechanism
for the creation of new land.

Contrast that with the scientific
explanation for the origin

of the most important thing of all,
the origin of the universe itself,

and for decades
we've been happy to say

the universe began at the Big Bang

and it's almost as if we're
not to ask what happened before.

There was nothing before,

there's no scientific mechanism to
explain how the Big Bang occurred.

But there are now plausible
theories that provide

a mechanism for how universes might
be made from apparently nothing.

So what is this magical
theory that explains

the origin of the universe,
and how did we find it?

Well, the answer is it's a theory
called inflation,

and really the clues
to the theory were there all along,

we just had to look for it.

They lie in the rules of the game.

If there's one basic rule
it's this - things have to happen.

Nothing, emptiness,
is about the only thing that's

forbidden by the rules of
quantum mechanics.

Before our universe
became filled with

particles of matter, it wasn't
empty, it was filled with energy,

and like the surface of the sea it
was constantly fluctuating, rippling

with a form of energy that causes
space to expand exponentially fast.

At the trough of one of the waves,
the energy driving

the expansion
fell below a certain level.

So that region stopped inflating and
the energy was transformed

into the recognisable particles
of today's universe.

And that transformation is what we
see as the Big Bang,

the birth of
our observable universe.

The theory of inflation
is extraordinary

and extraordinary claims
require extraordinary evidence.

Well, here is
the extraordinary evidence.

This is a photograph of
the oldest light in the universe

and it's got many intricate
and detailed properties.

The most obvious one is that
it's an extremely uniform glow,

it's almost all at the same
temperature.

This and all the other properties
of this ancient light are best

explained by an inflationary
expansion of the early universe.

No-one has thought of any theory
that can reproduce this

other than inflation,

and that is why I love physics.

Isn't that remarkable?

But, just like the formation
of islands or any other

mechanism in nature, inflation
needn't stop at one universe.

Why should it?

The process of inflation could be
going on eternally,

always making universes, even now.

And each one of these universes

could be like a ticket
in a lottery...

..bearing different numbers for
constants of nature...

..such as the strength of gravity
or the speed of light.

So amongst them all...

there has to be a winning ticket.

A human universe.

It's absolutely inevitable.

If the theory of inflation is
correct, it explains

how our universe appeared
apparently from nothing.

And it also strongly suggests that
there's not just our universe

but a vast number,
perhaps even an infinity of them.

Now we've known for a long time
that we're infinitesimal specks

in a vast universe,
but now the suggestion is that

we're infinitesimal specks
in a vast infinity of universes.

Our current best theory for
the origin of the universe,

backed up by experimental evidence,
suggests that there are an infinite

number of universes, an infinite
number of copies of you and me,

and that the existence of the
whole thing is inevitable.

No purpose, nothing special,
you are because you have to be.

How does that make you feel?

Well, the wonderful
thing is nobody knows,

nobody's worked it out yet,
so the answer is up to you.

What do you think?