Universe (2021–…): Season 1, Episode 1 - The Sun: God Star - full transcript
Since the first star lit up the universe, they have been engines of creation. Professor Brian Cox reveals how, ultimately, stars brought life and meaning to the universe.
Our universe is a place
Of infinite variety.
Two trillion galaxies...
...billions and billions of stars...
...and countless planets,
worlds beyond imagination.
The universe is so vast,
so incomprehensible, so terrifying,
that I think it's quite natural for
us to choose to live out our lives
complete oblivious to it.
Perhaps that's why there's a sense
of relief that rises with the dawn.
The brightening sky hides the stars
and the questions that they pose.
After all they are
the biggest questions.
how did the universe come to be?
Why are we here?
And how will it all end?
We have to face those questions
if we're ever to acquire
a true deep understanding
of ourselves.
You see, astronomy challenges us.
From one perspective,
we're just grains of sand adrift
in an infinite and
indifferent ocean.
But from another perspective, we are
nature's most magnificent creation,
collections of atoms that can think
and wonder about the universe
and choose to explore it.
OVERLAPPING LAUNCH COUNTDOWNS
We have lift-off... Zero...
In our quest for answers, we're
venturing ever further from home,
far beyond the planets...
...and out to the stars.
Our spacecraft are sending back
a stream
of extraordinary revelations...
...visions of alien worlds...
...with the ingredients
to create life.
We've seen galaxies collide...
...black holes devouring
star systems...
...and we may have glimpsed
the origin of the cosmos itself.
With every new observation,
every new piece of knowledge,
there is the opportunity to acquire
a deeper understanding.
And as we answer question
after question, we get ever closer
to being able to tell what is sure
the greatest story ever told.
Nasa's Parker Solar Probe,
a daring mission to shed light...
...on the mysteries of
our closest star.
This is a journey into
never- never- land, you might say.
Nasa's Parker solar Probe is the
first spacecraft to touch a star.
It's designed to fly through
the sun's atmosphere...
...braving temperatures no spacecraft
has ever endured.
The Parker solar Probe
is allowing us to know our star
as we've never known it before.
And it's also helping us to tell
the story of all the stars.
Our sun is from a long line of stars
dating back to the dawn of time...
...from fierce blue giants...
...which first lit up the universe...
...to later generations...
...whose deaths enriched the cosmos
with precious elements...
...the building blocks of
our solar system...
...and allowed our sun
to create the thing
which brings meaning to
the cosmos...
...life, you and me.
We have a strange relationship
with the stars,
somewhere between awe
and indifference.
I think we take our star,
the sun, for granted,
part because of
its predictability.
Every day, it rises in the east
and sets in the west...
...without any help or reverence
from us.
But many ancient cultures
deified the sun.
They treated it as a god.
And the sun gods were creators
and destroyers of worlds.
so which is it?
Well I think that the modern story
of the stars, as told by science,
which is indisputable an epic story,
stretching back over 13 billion
years to the origin of the universe,
places them firm in the realm
of the gods.
If we want to understand
where these gods came from...
...we have to go back...
...to a time before the stars.
In the beginning,
the universe was dark.
But it was not empty.
something was lurking in the void...
...stretching out tendrils.
The cosmic web grew to become
a vast structure...
...criss-crossing the entire universe.
It was formed by interlocking
filaments of dark matter.
And it was at the places
where these filaments met...
...the intersections...
...that the first stars, our sun's
earliest ancestors, were born.
The cosmic web is the scaffolding
of the universe,
the vast and intricate structure
that spans the void.
The web is made primarily
out of dark matter,
a mysterious substance
that dominates the universe,
although we don't know what it is.
It's one of the great mysteries
in modern physics.
It's probably some kind of particle
that interacts very weak
with itself and with light.
It doesn't interact with light.
You can't see it, which is why
it's called dark matter.
But it does influence the universe
through its gravity.
It was in the dark heart
of the cosmic web
that gravity began to sculpt
the ear universe...
...drawing together the two simplest
elements - hydrogen and helium...
...the raw material
for the very first stars.
Hydrogen gas clings to
the filaments of the web,
attracted there by the gravitational
pull of the dark matter.
And where those filaments cross,
the gas can become dense enough
to collapse under its own gravity
to form great clusters of galaxies,
each filled with billions of stars.
The universe was approaching
a turning point.
Hydrogen and helium
poured into the regions
where the filaments crossed...
...gathering into ever denser clouds.
Gravity asserted its grip...
...and the clouds of gas
began to collapse...
...becoming denser and denser.
And in the densest regions,
the gas became so hot...
...that nuclear fusion
reactions began.
And out of the maelstrom...
...the first gods emerged.
And there was light.
The stars illuminate the universe.
But that is the least interesting
thing that they do.
The thing that makes
the universe interesting,
that brings meaning to the universe
is that -
life, you and me.
And life is just chemistry.
And chemistry requires
complex chemical elements.
The on thing that existed
in the universe before the stars
was hydrogen and helium.
Life requires carbon and oxygen
and iron.
All those things were made
in a process called nuclear fusion,
in the cores of stars or even,
for the heavier elements like gold,
in the collisions of stars.
so, without the stars, the universe
would be uninteresting.
It would be meaningless.
It would be just an infinite
box of gas.
The first stars were monsters...
...hundreds of times as massive
as our sun.
They burnt with such ferocity
that they shone blue...
...with surface temperatures
in excess of 100,000 degrees.
They were the largest stars
ever to have lived...
...violent and volatile giants.
A star is essential
a balancing act.
The force of gravity
is constant trying to collapse it,
and that pushes its ingredients -
primarily hydrogen, single protons -
closer and closer together.
Now, when those protons
get close enough together,
another of the fundamental forces
of nature, the strong nuclear force,
takes over and it can stick
the protons together.
That releases energy, which creates
a pressure which holds the star up.
Now, the more massive the star, the
stronger the inward pull of gravity,
and the more energy has to be
released to maintain the balance,
and so the faster the ingredients
are used up.
...fighting the relentless
pull of gravity...
...consuming more and more
hydrogen fuel
to maintain their
precarious equilibrium.
for most of its life,
a star burns hydrogen -
the simplest chemical element,
with one proton in its nucleus -
into helium, with two protons.
Now, when it runs out of hydrogen
in the core,
the core starts to collapse
and heat up,
and the star responds by building
ever more complex elements.
so it makes carbon,
with six protons,
and oxygen, with eight protons,
releasing more and more energy
as it goes.
But when the star has assembled iron
in its core,
with 26 protons in its nucleus,
no more energy can be released.
The star loses its battle
against gravity.
It collapses
and in a final moment
of creation,
salvaged, if you like,
from its destruction,
it distributes those new minted
heavy chemical elements
out into the universe.
I imagine we could journey back
in time
and watch the first star live
out its brief, luminous life.
After on a million years,
the star used up all of its fuel...
...the core collapsed...
...the star imploded...
...and then rebounded
in a colossal explosion -
a supernova.
In death, the first stars began
to transform the cosmos,
enriching the ocean of hydrogen
and helium,
which filled the
universe with heavy elements,
to build new generations
of more complex stars.
Over time, these elements
gathered together...
...creating rich clouds of gas
and dust.
Nurseries where new generations
of stars were born.
And not just stars,
but families of stars -
the first galaxies.
And around this time,
some of the ear star systems
formed
in our own galaxy,
the Milky Way.
A new age of complexity
was dawning in the universe.
Now there were stars of
different sizes...
...and different colours...
...and, crucial,
new bodies had appeared...
...planets.
Places where the rich chemical
elements
built by previous generations of
stars could final find a home.
countless billions of stars
have come and gone
since those first giants illuminated
the darkness,
each enriching the universe
with the material
out of which the next generation
formed.
Blue stars and white stars,
single stars,
double stars, even triple star
systems orbiting around each other.
The conditions were now right for
those stars to drive the universe
into a new and profound
age of complexity.
Our Sun was formed from the ashes
of generations of ancestors.
Just one small star in a galaxy
of billions of brilliant gods.
for the first million years
of its life,
the Sun was virtual alone,
wreathed in clouds of gas and dust.
The dust slow clumped together...
...forming clusters,
the size of pebbles,
then boulders...
...and final...
...planets.
But the planets were lifeless rocks.
On the Sun had the power to turn
them into worlds.
some were too far away from the Sun.
Ice giants -
frozen, seeming, into infertility.
Others formed too close to the
Sun,
seared by a relentless light.
They became scorched desert worlds,
but there was a planet in the Sun's
family
that quite by chance formed neither
too close nor too far away.
An arcadia, where our star could
breathe life into dust.
The planets are just the leftovers
from the formation of stars.
The sort of debris, if you like.
It's just little specks orbiting
around those magnificent flames,
but the planets are also the
places in the universe
where gravity has concentrated the
heavy elements
built by previous generations of
stars.
And that makes the planets
the canvas
on which the stars can create.
The canvas on which the stars
can create,
what do I mean by that?
Well just look around.
Everywhere you look on Earth,
there is complexity.
Not on mountains and rivers,
but living things, animals and
plants, human beings,
human civilisation,
the most complex thing we know of
anywhere in the universe.
so you have to ask yourself,
how can it be that such complexity
can emerge complete natural
in the universe?
Well the answer, in fact, was known
in the 19th century,
and it comes from the science of
thermodynamics.
In the 19th century,
people were interested in the
efficiency of steam engines,
and steam engines are, after all
the machines that powered
the factories that allowed people to
build increasing complex things.
And it turns out that the on thing
that matters for a steam engine,
the thing that determines its
efficiency,
the thing that allows it to do work
and build things
is the temperature difference
between the fire,
the furnace
and the heart of the steam engine
and the cold environment
surrounding it.
In the universe, the stars
are hot spots in a cold sky.
We are sitting, in a very real
sense'
inside a giant steam engine, powered
by the furnace of the Sun.
And it's in that sense that the
stars are the creators
of complexity in the universe.
But creating complexity
is a subtle art.
You need an engine -
in this case, a star
that's not too wild and flashy.
A star which is consistent enough
for long enough
to kindle
the sparks of life...
...and allow those sparks to flicker
and flourish.
The most important property
of a star,
if it's to nurture a civilisation,
is magnificent dependability.
No-one knows exact how life
on Earth emerged...
...but what we do know is that at
some point,
primitive cells living in the ocean
began using the Sun's energy
to power life-giving chemical
reactions.
These cells formed a bridge
between Earth and Sun,
delicate engines which harness the
fires of our star,
using sunlight to turn carbon
dioxide and water into food.
This process,
known as photosynthesis,
unleashed the Sun's creative
power...
...and drove the evolution
of complexity...
...from primitive bacteria,
to plants and trees...
...and,
ultimate,
to you and me.
Photosynthesis is a process that's
very easy to describe in words.
The plants take energy from the Sun
then use it to react carbon dioxide
and water together
to make sugars and a waste product,
oxygen.
Real easy to say.
Very difficult to do.
I mean, there's a part of
that photosynthetic machinery,
everything you see here,
every plant on the planet's
got a photosystem, too.
It's comprised of 46,630 atoms,
all working together in an intricate
machine.
Very efficient. It took billions of
years of evolution.
Then we eat the plants, or we eat
something that's eaten the plants
and we do the reverse reaction.
We take those sugars and we breathe
in that waste product, oxygen,
react them together, release a bit
of energy,
a bit of the stored sunlight,
if you like,
and we use that energy to maintain
our structure,
to grow, to live.
Trillions of stars have existed
since the universe began...
...but ours has nurtured that most
miraculous thing,
life.
And that makes the Sun
a true remarkable star.
That is the on star we know
of
anywhere where there are collections
of atoms in orbits around it,
you and me,
that have named
it.
The Sun, our Sun.
We've worshipped it, deified it
since the dawn of history.
In fact, it's been argued
that the Sun lies at the foundation
of all religion, and there
may be some truth in that.
In fact, I think there is a deep
truth in that,
because we all owe our existence,
this brief time we have in the
universe,
to that star.
In fact, in a deeper sense, to all
the stars.
We don't need to invent imaginary
gods to explain the universe.
We can replace them with
the real thing.
Everyone we love...
...everything we value...
...our supreme accomplishments
as a civilisation...
...were created and crafted...
...by stars.
There are over 200 billion
stars in our galaxy...
...and there are two trillion
galaxies in the observable universe.
We're living in the Age of Stars...
...an era of light and life
in the cosmos.
From our fleeting human
perspective, stars seem eternal...
...but even gods are not immortal.
Where there is light,
there is darkness.
Stars are creators...
...but they can be jealous
guardians of their creations.
Many smaller stars don't die
in spectacular explosions,
instead, they slowly
fade away.
They hang on to the precious
elements they made,
becoming fossil stars...
...and as more fossils
litter the universe,
more life-giving elements
remain locked away,
starving the cosmos of the material
needed
to make new generations of stars.
The Age of Stars may seem infinite,
but it had a beginning
and it will also have an end.
I imagine a timeline of the universe
and imagine that this is the origin
of the universe,
the Big Bang,
13.8 billion years ago.
After 100 million years
or so, the first stars formed.
On this scale, one centimetre
is about 20 million years.
After four billion years, the peak
rate of star formation occurred.
The maximum number of new stars
were born.
After nine billion years,
our Sun was born.
And today we stand,
13.8 billion years later,
about half-way
through the lifetime of our Sun.
Now, in about five billion years'
time,
our Sun will die, but new stars
will be born
and many of the oldest
stars in the universe,
the smallest stars,
will continue to shine.
In fact, we think that the last
star will cease to shine,
the universe will go dark,
in around ten trillion years.
On this scale, that's about 5,OOO
metres away from the Big Bang.
But that's not
the end of the universe.
As far as we know, the universe
will continue expanding forever.
And so the Age of Starlight
is the briefest moment of time
in the infinite history
of the universe.
The Age of Darkness will go
on and on and on.
Stars won't just disappear,
of course.
They'll be here for aeons to come.
But over time, the universe,
will grow darker,
colder
and emptier.
There are stars around today
that existed
close to the beginning
of the Age of Stars...
...and some of them
will also witness the end.
They're the longest lived
stars in the universe,
red dwarfs.
TRAPPIST-1 is one
of these ancients.
It's already more than seven billion
years old,
almost twice as old as our Sun...
...but on around a tenth
of the size...
...and less than 1% as bright.
It's a cool star,
slow- burning...
...and that is the secret
of its longevity.
Because they burn slow,
red dwarfs live
for a very long time...
...far longer than any other star.
Like the Sun, TRAPPIST-1
has its own planets -
seven rocky worlds,
each rough the size of Earth.
some may have atmospheres
and even oceans...
...but there the similarity ends...
...because these are strange worlds.
Every one of these planets
is locked in its orbit,
one side facing TRAPPIST-1,
the other side frozen,
permanent exposed to the cold void
of space.
If you could stand on the surface
of one of these ancient worlds...
...as the aeons passed...
...you could watch the future
of the cosmos slow unfold.
And one day,
five billion years from now,
you'd see our Sun flicker
and fade away forever.
The death of our Sun will
probably go unremarked.
We had hope that we'll be
around to see it.
Maybe some alien astronomer
on a world far away
across the Milky Way will see it
through the end of their telescope,
but I don't think they'll give
it a second thought.
We've seen hundreds of stars
die
and we don't give them
a second thought.
But I think the death of our Sun
will matter here local
in this little corner of the galaxy,
because it will mark the end
of a glorious time
in the history
of our galaxy,
where meaning, where science and
literature
and art and poetry and
music existed here.
And that does matter.
Why does meaning
have to be eternal?
It's the fragility of our lives
that makes them valuable.
I think the wonderful thing
is that our star
has taken the laws of nature here on
this planet
and crafted such a
magnificent expression of them.
You, me and all this.
Stars like TRAPPIST-1 will linger on
long after the death of our Sun.
We will never know the name
of the last star...
...but we know that the last star to
shine...
...will be a red dwarf.
The last star will slow cool
and fade away.
With its passing, the universe
will become, once again,
a void,
without light
or life
or meaning.
The stars illuminate the universe
and create its most intricate
structures,
and one day they will all be gone.
The stars are gods,
but they are mortal gods.
And when that time comes when
the last stars have faded
and all possibility of life
and meaning in the universe
has faded with them,
they will have left the most
profound legacy
because for a moment in the long
history of the universe,
the stars illuminated the dark
and allowed us
to illuminate it, too.
Who Knows Where The
Time Goes? by Fairport Convention
We want to study the Sun because it
teaches us a lot about stars.
It teaches us a lot about all
the other millions and billions
of stars in our galaxy and beyond.
There was a moment when we were
putting the spacecraft together
that I just took a moment and looked
at the spacecraft
and realised
this is going into a star.
And to realise how special
it was
to be able to have worked on this
and that humanity decided this was
something we wanted to do.
Status check.
Go, Delta.
Go, PSP.
Minus 15.
Launch night,
I was sick to my stomach.
Five, four, three,
two, one,
zero.
Lift-off of the mighty Delta IV
Heavy rocket
with Nasa’s Parker
solar Probe.
There we go.
The spacecraft is the first that
NASA has named after a living
person because Eugene Parker is
really such, you know,
an eminent physicist in our field.
The Delta IV Heavy is a very
slow rocket
compared to the other launches I've
seen,
so I just saw fireballs and was
very, very frightened for a while.
25 seconds into flight.
Temp pressures continue to
look good on all three boosters.
Then realising that this was all
OK,
as it slowly made its way
up into the sky.
Now, 50 seconds into flight.
Parker Solar Probe is so
revolutionary
because it's the first time that
we're actually going in
to touch the Sun.
We're going 94% of the way from the
Earth to the Sun
to actually experience the
solar corona, the Sun's atmosphere.
I think at closest approach,
it’ll be about eight solar
radii from the Sun,
which is just mind-blowingly
close.
So we were expecting things
to be very hot,
over 2,500
Fahrenheit,
but in a soup of a million
degree plasma.
That's a real challenge
for the spacecraft
to survive that environment.
So in order to do that, there's
a very large heat shield
on the front of the spacecraft,
which protects the majority of the
instruments
which are sat
behind on the spacecraft body.
What makes Parker so great
is the fact that it has a set
of instruments that work together
in order to look in all directions,
in order to solve those big
mysteries about the solar wind.
The solar corona has been mysterious
to us since we've known about it,
so it's a very strange thing.
The surface of the Sun is sort
of 6,000 degrees,
and then above that, you have this
very thin atmosphere
that's a million degrees,
super hot.
And the way that's heated, we know
it has something to do
with magnetic fields, but we don't
know exactly how it works.
That's where the solar wind
is generated.
We don't know quite exactly
how that works, either.
Other things that have come out of
this are coronal mass ejections.
When we originally did the proposal,
we were thinking that we would see
five
in the entire seven year
mission, if we were lucky.
We ended up seeing around four
to five in the first year,
so there has been just a total
switch
in terms of how active the
Sun is
or what we classify as
coronal mass ejections.
Maybe a little bit of both.
It is a joy to see all the data
coming back.
It's a joy to share it with others
and to see them be as curious
as I have been for the last decade.
So Parker’s just begun its mission,
really,
and it’s already really started to
truly transform our understanding
for how the Sun works.
Next time...
...we had deeper
into the galaxy...
...on the hunt for alien worlds...
...and perhaps the first signs of
life.
Journey through the universe
with the Open University
and learn more about stars, planets
and galaxies with this free poster.
Order your poster by calling...
Or go to...
and follow the links to the
Open University.
Of infinite variety.
Two trillion galaxies...
...billions and billions of stars...
...and countless planets,
worlds beyond imagination.
The universe is so vast,
so incomprehensible, so terrifying,
that I think it's quite natural for
us to choose to live out our lives
complete oblivious to it.
Perhaps that's why there's a sense
of relief that rises with the dawn.
The brightening sky hides the stars
and the questions that they pose.
After all they are
the biggest questions.
how did the universe come to be?
Why are we here?
And how will it all end?
We have to face those questions
if we're ever to acquire
a true deep understanding
of ourselves.
You see, astronomy challenges us.
From one perspective,
we're just grains of sand adrift
in an infinite and
indifferent ocean.
But from another perspective, we are
nature's most magnificent creation,
collections of atoms that can think
and wonder about the universe
and choose to explore it.
OVERLAPPING LAUNCH COUNTDOWNS
We have lift-off... Zero...
In our quest for answers, we're
venturing ever further from home,
far beyond the planets...
...and out to the stars.
Our spacecraft are sending back
a stream
of extraordinary revelations...
...visions of alien worlds...
...with the ingredients
to create life.
We've seen galaxies collide...
...black holes devouring
star systems...
...and we may have glimpsed
the origin of the cosmos itself.
With every new observation,
every new piece of knowledge,
there is the opportunity to acquire
a deeper understanding.
And as we answer question
after question, we get ever closer
to being able to tell what is sure
the greatest story ever told.
Nasa's Parker Solar Probe,
a daring mission to shed light...
...on the mysteries of
our closest star.
This is a journey into
never- never- land, you might say.
Nasa's Parker solar Probe is the
first spacecraft to touch a star.
It's designed to fly through
the sun's atmosphere...
...braving temperatures no spacecraft
has ever endured.
The Parker solar Probe
is allowing us to know our star
as we've never known it before.
And it's also helping us to tell
the story of all the stars.
Our sun is from a long line of stars
dating back to the dawn of time...
...from fierce blue giants...
...which first lit up the universe...
...to later generations...
...whose deaths enriched the cosmos
with precious elements...
...the building blocks of
our solar system...
...and allowed our sun
to create the thing
which brings meaning to
the cosmos...
...life, you and me.
We have a strange relationship
with the stars,
somewhere between awe
and indifference.
I think we take our star,
the sun, for granted,
part because of
its predictability.
Every day, it rises in the east
and sets in the west...
...without any help or reverence
from us.
But many ancient cultures
deified the sun.
They treated it as a god.
And the sun gods were creators
and destroyers of worlds.
so which is it?
Well I think that the modern story
of the stars, as told by science,
which is indisputable an epic story,
stretching back over 13 billion
years to the origin of the universe,
places them firm in the realm
of the gods.
If we want to understand
where these gods came from...
...we have to go back...
...to a time before the stars.
In the beginning,
the universe was dark.
But it was not empty.
something was lurking in the void...
...stretching out tendrils.
The cosmic web grew to become
a vast structure...
...criss-crossing the entire universe.
It was formed by interlocking
filaments of dark matter.
And it was at the places
where these filaments met...
...the intersections...
...that the first stars, our sun's
earliest ancestors, were born.
The cosmic web is the scaffolding
of the universe,
the vast and intricate structure
that spans the void.
The web is made primarily
out of dark matter,
a mysterious substance
that dominates the universe,
although we don't know what it is.
It's one of the great mysteries
in modern physics.
It's probably some kind of particle
that interacts very weak
with itself and with light.
It doesn't interact with light.
You can't see it, which is why
it's called dark matter.
But it does influence the universe
through its gravity.
It was in the dark heart
of the cosmic web
that gravity began to sculpt
the ear universe...
...drawing together the two simplest
elements - hydrogen and helium...
...the raw material
for the very first stars.
Hydrogen gas clings to
the filaments of the web,
attracted there by the gravitational
pull of the dark matter.
And where those filaments cross,
the gas can become dense enough
to collapse under its own gravity
to form great clusters of galaxies,
each filled with billions of stars.
The universe was approaching
a turning point.
Hydrogen and helium
poured into the regions
where the filaments crossed...
...gathering into ever denser clouds.
Gravity asserted its grip...
...and the clouds of gas
began to collapse...
...becoming denser and denser.
And in the densest regions,
the gas became so hot...
...that nuclear fusion
reactions began.
And out of the maelstrom...
...the first gods emerged.
And there was light.
The stars illuminate the universe.
But that is the least interesting
thing that they do.
The thing that makes
the universe interesting,
that brings meaning to the universe
is that -
life, you and me.
And life is just chemistry.
And chemistry requires
complex chemical elements.
The on thing that existed
in the universe before the stars
was hydrogen and helium.
Life requires carbon and oxygen
and iron.
All those things were made
in a process called nuclear fusion,
in the cores of stars or even,
for the heavier elements like gold,
in the collisions of stars.
so, without the stars, the universe
would be uninteresting.
It would be meaningless.
It would be just an infinite
box of gas.
The first stars were monsters...
...hundreds of times as massive
as our sun.
They burnt with such ferocity
that they shone blue...
...with surface temperatures
in excess of 100,000 degrees.
They were the largest stars
ever to have lived...
...violent and volatile giants.
A star is essential
a balancing act.
The force of gravity
is constant trying to collapse it,
and that pushes its ingredients -
primarily hydrogen, single protons -
closer and closer together.
Now, when those protons
get close enough together,
another of the fundamental forces
of nature, the strong nuclear force,
takes over and it can stick
the protons together.
That releases energy, which creates
a pressure which holds the star up.
Now, the more massive the star, the
stronger the inward pull of gravity,
and the more energy has to be
released to maintain the balance,
and so the faster the ingredients
are used up.
...fighting the relentless
pull of gravity...
...consuming more and more
hydrogen fuel
to maintain their
precarious equilibrium.
for most of its life,
a star burns hydrogen -
the simplest chemical element,
with one proton in its nucleus -
into helium, with two protons.
Now, when it runs out of hydrogen
in the core,
the core starts to collapse
and heat up,
and the star responds by building
ever more complex elements.
so it makes carbon,
with six protons,
and oxygen, with eight protons,
releasing more and more energy
as it goes.
But when the star has assembled iron
in its core,
with 26 protons in its nucleus,
no more energy can be released.
The star loses its battle
against gravity.
It collapses
and in a final moment
of creation,
salvaged, if you like,
from its destruction,
it distributes those new minted
heavy chemical elements
out into the universe.
I imagine we could journey back
in time
and watch the first star live
out its brief, luminous life.
After on a million years,
the star used up all of its fuel...
...the core collapsed...
...the star imploded...
...and then rebounded
in a colossal explosion -
a supernova.
In death, the first stars began
to transform the cosmos,
enriching the ocean of hydrogen
and helium,
which filled the
universe with heavy elements,
to build new generations
of more complex stars.
Over time, these elements
gathered together...
...creating rich clouds of gas
and dust.
Nurseries where new generations
of stars were born.
And not just stars,
but families of stars -
the first galaxies.
And around this time,
some of the ear star systems
formed
in our own galaxy,
the Milky Way.
A new age of complexity
was dawning in the universe.
Now there were stars of
different sizes...
...and different colours...
...and, crucial,
new bodies had appeared...
...planets.
Places where the rich chemical
elements
built by previous generations of
stars could final find a home.
countless billions of stars
have come and gone
since those first giants illuminated
the darkness,
each enriching the universe
with the material
out of which the next generation
formed.
Blue stars and white stars,
single stars,
double stars, even triple star
systems orbiting around each other.
The conditions were now right for
those stars to drive the universe
into a new and profound
age of complexity.
Our Sun was formed from the ashes
of generations of ancestors.
Just one small star in a galaxy
of billions of brilliant gods.
for the first million years
of its life,
the Sun was virtual alone,
wreathed in clouds of gas and dust.
The dust slow clumped together...
...forming clusters,
the size of pebbles,
then boulders...
...and final...
...planets.
But the planets were lifeless rocks.
On the Sun had the power to turn
them into worlds.
some were too far away from the Sun.
Ice giants -
frozen, seeming, into infertility.
Others formed too close to the
Sun,
seared by a relentless light.
They became scorched desert worlds,
but there was a planet in the Sun's
family
that quite by chance formed neither
too close nor too far away.
An arcadia, where our star could
breathe life into dust.
The planets are just the leftovers
from the formation of stars.
The sort of debris, if you like.
It's just little specks orbiting
around those magnificent flames,
but the planets are also the
places in the universe
where gravity has concentrated the
heavy elements
built by previous generations of
stars.
And that makes the planets
the canvas
on which the stars can create.
The canvas on which the stars
can create,
what do I mean by that?
Well just look around.
Everywhere you look on Earth,
there is complexity.
Not on mountains and rivers,
but living things, animals and
plants, human beings,
human civilisation,
the most complex thing we know of
anywhere in the universe.
so you have to ask yourself,
how can it be that such complexity
can emerge complete natural
in the universe?
Well the answer, in fact, was known
in the 19th century,
and it comes from the science of
thermodynamics.
In the 19th century,
people were interested in the
efficiency of steam engines,
and steam engines are, after all
the machines that powered
the factories that allowed people to
build increasing complex things.
And it turns out that the on thing
that matters for a steam engine,
the thing that determines its
efficiency,
the thing that allows it to do work
and build things
is the temperature difference
between the fire,
the furnace
and the heart of the steam engine
and the cold environment
surrounding it.
In the universe, the stars
are hot spots in a cold sky.
We are sitting, in a very real
sense'
inside a giant steam engine, powered
by the furnace of the Sun.
And it's in that sense that the
stars are the creators
of complexity in the universe.
But creating complexity
is a subtle art.
You need an engine -
in this case, a star
that's not too wild and flashy.
A star which is consistent enough
for long enough
to kindle
the sparks of life...
...and allow those sparks to flicker
and flourish.
The most important property
of a star,
if it's to nurture a civilisation,
is magnificent dependability.
No-one knows exact how life
on Earth emerged...
...but what we do know is that at
some point,
primitive cells living in the ocean
began using the Sun's energy
to power life-giving chemical
reactions.
These cells formed a bridge
between Earth and Sun,
delicate engines which harness the
fires of our star,
using sunlight to turn carbon
dioxide and water into food.
This process,
known as photosynthesis,
unleashed the Sun's creative
power...
...and drove the evolution
of complexity...
...from primitive bacteria,
to plants and trees...
...and,
ultimate,
to you and me.
Photosynthesis is a process that's
very easy to describe in words.
The plants take energy from the Sun
then use it to react carbon dioxide
and water together
to make sugars and a waste product,
oxygen.
Real easy to say.
Very difficult to do.
I mean, there's a part of
that photosynthetic machinery,
everything you see here,
every plant on the planet's
got a photosystem, too.
It's comprised of 46,630 atoms,
all working together in an intricate
machine.
Very efficient. It took billions of
years of evolution.
Then we eat the plants, or we eat
something that's eaten the plants
and we do the reverse reaction.
We take those sugars and we breathe
in that waste product, oxygen,
react them together, release a bit
of energy,
a bit of the stored sunlight,
if you like,
and we use that energy to maintain
our structure,
to grow, to live.
Trillions of stars have existed
since the universe began...
...but ours has nurtured that most
miraculous thing,
life.
And that makes the Sun
a true remarkable star.
That is the on star we know
of
anywhere where there are collections
of atoms in orbits around it,
you and me,
that have named
it.
The Sun, our Sun.
We've worshipped it, deified it
since the dawn of history.
In fact, it's been argued
that the Sun lies at the foundation
of all religion, and there
may be some truth in that.
In fact, I think there is a deep
truth in that,
because we all owe our existence,
this brief time we have in the
universe,
to that star.
In fact, in a deeper sense, to all
the stars.
We don't need to invent imaginary
gods to explain the universe.
We can replace them with
the real thing.
Everyone we love...
...everything we value...
...our supreme accomplishments
as a civilisation...
...were created and crafted...
...by stars.
There are over 200 billion
stars in our galaxy...
...and there are two trillion
galaxies in the observable universe.
We're living in the Age of Stars...
...an era of light and life
in the cosmos.
From our fleeting human
perspective, stars seem eternal...
...but even gods are not immortal.
Where there is light,
there is darkness.
Stars are creators...
...but they can be jealous
guardians of their creations.
Many smaller stars don't die
in spectacular explosions,
instead, they slowly
fade away.
They hang on to the precious
elements they made,
becoming fossil stars...
...and as more fossils
litter the universe,
more life-giving elements
remain locked away,
starving the cosmos of the material
needed
to make new generations of stars.
The Age of Stars may seem infinite,
but it had a beginning
and it will also have an end.
I imagine a timeline of the universe
and imagine that this is the origin
of the universe,
the Big Bang,
13.8 billion years ago.
After 100 million years
or so, the first stars formed.
On this scale, one centimetre
is about 20 million years.
After four billion years, the peak
rate of star formation occurred.
The maximum number of new stars
were born.
After nine billion years,
our Sun was born.
And today we stand,
13.8 billion years later,
about half-way
through the lifetime of our Sun.
Now, in about five billion years'
time,
our Sun will die, but new stars
will be born
and many of the oldest
stars in the universe,
the smallest stars,
will continue to shine.
In fact, we think that the last
star will cease to shine,
the universe will go dark,
in around ten trillion years.
On this scale, that's about 5,OOO
metres away from the Big Bang.
But that's not
the end of the universe.
As far as we know, the universe
will continue expanding forever.
And so the Age of Starlight
is the briefest moment of time
in the infinite history
of the universe.
The Age of Darkness will go
on and on and on.
Stars won't just disappear,
of course.
They'll be here for aeons to come.
But over time, the universe,
will grow darker,
colder
and emptier.
There are stars around today
that existed
close to the beginning
of the Age of Stars...
...and some of them
will also witness the end.
They're the longest lived
stars in the universe,
red dwarfs.
TRAPPIST-1 is one
of these ancients.
It's already more than seven billion
years old,
almost twice as old as our Sun...
...but on around a tenth
of the size...
...and less than 1% as bright.
It's a cool star,
slow- burning...
...and that is the secret
of its longevity.
Because they burn slow,
red dwarfs live
for a very long time...
...far longer than any other star.
Like the Sun, TRAPPIST-1
has its own planets -
seven rocky worlds,
each rough the size of Earth.
some may have atmospheres
and even oceans...
...but there the similarity ends...
...because these are strange worlds.
Every one of these planets
is locked in its orbit,
one side facing TRAPPIST-1,
the other side frozen,
permanent exposed to the cold void
of space.
If you could stand on the surface
of one of these ancient worlds...
...as the aeons passed...
...you could watch the future
of the cosmos slow unfold.
And one day,
five billion years from now,
you'd see our Sun flicker
and fade away forever.
The death of our Sun will
probably go unremarked.
We had hope that we'll be
around to see it.
Maybe some alien astronomer
on a world far away
across the Milky Way will see it
through the end of their telescope,
but I don't think they'll give
it a second thought.
We've seen hundreds of stars
die
and we don't give them
a second thought.
But I think the death of our Sun
will matter here local
in this little corner of the galaxy,
because it will mark the end
of a glorious time
in the history
of our galaxy,
where meaning, where science and
literature
and art and poetry and
music existed here.
And that does matter.
Why does meaning
have to be eternal?
It's the fragility of our lives
that makes them valuable.
I think the wonderful thing
is that our star
has taken the laws of nature here on
this planet
and crafted such a
magnificent expression of them.
You, me and all this.
Stars like TRAPPIST-1 will linger on
long after the death of our Sun.
We will never know the name
of the last star...
...but we know that the last star to
shine...
...will be a red dwarf.
The last star will slow cool
and fade away.
With its passing, the universe
will become, once again,
a void,
without light
or life
or meaning.
The stars illuminate the universe
and create its most intricate
structures,
and one day they will all be gone.
The stars are gods,
but they are mortal gods.
And when that time comes when
the last stars have faded
and all possibility of life
and meaning in the universe
has faded with them,
they will have left the most
profound legacy
because for a moment in the long
history of the universe,
the stars illuminated the dark
and allowed us
to illuminate it, too.
Who Knows Where The
Time Goes? by Fairport Convention
We want to study the Sun because it
teaches us a lot about stars.
It teaches us a lot about all
the other millions and billions
of stars in our galaxy and beyond.
There was a moment when we were
putting the spacecraft together
that I just took a moment and looked
at the spacecraft
and realised
this is going into a star.
And to realise how special
it was
to be able to have worked on this
and that humanity decided this was
something we wanted to do.
Status check.
Go, Delta.
Go, PSP.
Minus 15.
Launch night,
I was sick to my stomach.
Five, four, three,
two, one,
zero.
Lift-off of the mighty Delta IV
Heavy rocket
with Nasa’s Parker
solar Probe.
There we go.
The spacecraft is the first that
NASA has named after a living
person because Eugene Parker is
really such, you know,
an eminent physicist in our field.
The Delta IV Heavy is a very
slow rocket
compared to the other launches I've
seen,
so I just saw fireballs and was
very, very frightened for a while.
25 seconds into flight.
Temp pressures continue to
look good on all three boosters.
Then realising that this was all
OK,
as it slowly made its way
up into the sky.
Now, 50 seconds into flight.
Parker Solar Probe is so
revolutionary
because it's the first time that
we're actually going in
to touch the Sun.
We're going 94% of the way from the
Earth to the Sun
to actually experience the
solar corona, the Sun's atmosphere.
I think at closest approach,
it’ll be about eight solar
radii from the Sun,
which is just mind-blowingly
close.
So we were expecting things
to be very hot,
over 2,500
Fahrenheit,
but in a soup of a million
degree plasma.
That's a real challenge
for the spacecraft
to survive that environment.
So in order to do that, there's
a very large heat shield
on the front of the spacecraft,
which protects the majority of the
instruments
which are sat
behind on the spacecraft body.
What makes Parker so great
is the fact that it has a set
of instruments that work together
in order to look in all directions,
in order to solve those big
mysteries about the solar wind.
The solar corona has been mysterious
to us since we've known about it,
so it's a very strange thing.
The surface of the Sun is sort
of 6,000 degrees,
and then above that, you have this
very thin atmosphere
that's a million degrees,
super hot.
And the way that's heated, we know
it has something to do
with magnetic fields, but we don't
know exactly how it works.
That's where the solar wind
is generated.
We don't know quite exactly
how that works, either.
Other things that have come out of
this are coronal mass ejections.
When we originally did the proposal,
we were thinking that we would see
five
in the entire seven year
mission, if we were lucky.
We ended up seeing around four
to five in the first year,
so there has been just a total
switch
in terms of how active the
Sun is
or what we classify as
coronal mass ejections.
Maybe a little bit of both.
It is a joy to see all the data
coming back.
It's a joy to share it with others
and to see them be as curious
as I have been for the last decade.
So Parker’s just begun its mission,
really,
and it’s already really started to
truly transform our understanding
for how the Sun works.
Next time...
...we had deeper
into the galaxy...
...on the hunt for alien worlds...
...and perhaps the first signs of
life.
Journey through the universe
with the Open University
and learn more about stars, planets
and galaxies with this free poster.
Order your poster by calling...
Or go to...
and follow the links to the
Open University.