How the Universe Works
Season 5
TV Series | How the Universe Works | Contents page
How the Universe Works S05E01
Part 1
April 18, 2021, 7:46 p.m.
Join us on a journey to infinity and beyond,
to a place where the rules of physics collapse.
Imagine a place surrounded by trillions of icy rocks...
Unlock the secrets of earth's first oceans,
and we'll unlock the secrets of alien life.
And the magnetic fields that help stars ignite,
they shape entire galaxies.
And what's going on in its outer reaches determines
whether we live or die.
Captions paid for by discovery communications
The first second of the universe has barely begun.
And the shortest possible units of time, planck times,
are flying by in their millionths.
The universe is a super-hot ball of radiation,
billions of times smaller than an atom,
and dense beyond imagination.
Gravity has begun shaping the future of the cosmos.
But as the universe expands, temperature drops.
Another force arrives on the scene, the strong force.
Without the strong nuclear force,
the nuclei of the atoms themselves
would all disintegrate.
Three forces ...
gravity, the strong force, and the fractured super force ...
rule the universe as it hurdles towards its next milestone,
an event that sets out the blueprint for the galaxies
that fill the cosmos today.
We think this event happened
because it explains a longstanding mystery.
Everywhere we've looked in the universe,
its billions of galaxies are spread evenly,
the same number in every direction.
Nobody could explain why.
All of these parts of the universe must have at one point
been in contact with each other.
It's kind of like having two people
who live on opposite sides of a country
getting up at the same time,
eating the same breakfast, dressing the same way,
even when they don't talk to each other.
There must be something common in their past that links them.
This problem needed a solution.
And in 1979, a young cosmologist named Alan guth proposed one.
He called it inflation.
This was very exciting.
I suddenly realized that this might be the key
to a very important secret of the universe.
But at the same time, I was, of course, very nervous
because it was all new.
And I was shaky about whether or not it was right.
Guth speculated that the infant universe
went through a phenomenal growth spurt.
Cosmic inflation was a moment in the history,
the very early history, of the universe
when the expansion suddenly accelerated.
It got huge for the briefest moments of time.
Just 10 million planck times after the big bang,
a tiny volume of space suddenly starts to expand
much more quickly than before.
This inflation is so rapid that it turns chaos into order,
spreading the constituents of our universe
evenly throughout space
and fixing their positions within it.
As the universe cooled down in those earliest moments,
it increased in volume by a factor of 10 to the 90th,
in a millionth of a billionth of a billionth of a second.
It's like a grain of sand
swelling to larger than the sun faster than the speed of light.
Well, have we violated Einstein's laws?
Nothing can go faster than the speed of light.
And here is one of the real subtle points
about the big bang.
Space can expand so much that two objects appear to move apart
faster than the speed of light.
But they're not moving.
It's the space in between them that's growing.
Guth's audacious idea, the inflationary universe,
could push the limit of our understanding back
to the very first moments of the very first second.
But how could we ever test it?
How could we peer into the birth of creation?
TV static holds a clue.
1% of the static on this screen
comes from light from the big bang.
In 196♥4♥, astronomers arno penzias and Robert Wilson
were listening to radio signals from space.
But in every direction,
they were picking up a background hum.
Puzzled by the hum, they suspected they knew the culprit
and swept the entire receiver free of pigeon droppings,
but to no avail.
What penzias and Wilson had stumbled upon
was the afterglow of the fireball
created by the big bang.
As the universe expanded, it cooled.
After a few hundred thousand years,
it was just protons and electrons flying around.
But at some point, the universe cooled enough
that when an electron and proton got together
all over the universe, essentially all at once,
the universe became transparent.
Kaku: Think of a gigantic fog that suddenly lifts.
Before the fog lifts,
you can only see a few feet in front of you.
Then suddenly everything becomes clear.
That's what happened 380,000 years after the big bang.
Ever since that moment,
380,000 years after the big bang,
this light has traveled uninterrupted through space.
Scientists call it the cosmic microwave background.
If you were to write down a handful
of the greatest scientific discoveries of all time,
one of them might be the discovery of DNA.
Another one might be
the discovery of a cosmic microwave background.
That's how big this discovery was.
We once believed creating a star was easy.
Take a huge cloud of gas,
to a hot ball of plasma.
Temperatures and pressures rise until fusion sparks,
and a star is born.
Now scientists think gravity alone is not enough.
To construct a star, you also need magnetism.
The primary mover when you're forming a star is gravity.
The material condenses in the center to form a star,
and as that star forms there's material swirling around it,
attracted to that central mass by its gravity,
but there's a problem.
How the Universe Works
Season 5
TV Series | How the Universe Works | Contents page