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
completely 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 truly 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 liftoff... 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 surely the greatest story ever told.
＃ 带我走。 #
# Take me away. #
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,
partly 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 indisputably an epic story,
stretching back over 13 billion years to the origin of the universe,
places them firmly 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...
..crisscrossing the entire universe.
It was formed by interlocking filaments of dark matter.
And it was at the places where these filaments met...
..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 weakly 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 early 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 only 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.
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