All language subtitles for HTUW S05x01 Most Amazing Discoveries

SUB BY : DENI AUROR@
https://aurorarental.blogspot.com/

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 1964, 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,

add some gravity,

and stand back as the gravity crushes the gas down

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.

This stuff has what's called angular momentum.

Angular momentum is the force of rotation

that keeps the clouds of gas spinning around the center

of the forming star.

It works against gravity,

smearing the gas into a thin disk.

Young stars, or protostars,

can only ignite if the central gas cloud

reaches a super hot, dense state.

But the disk spins around the center too fast

for gravity to do its work.

Scientists now understand that a third force

is at at play here.

That's where magnetism can play a role.

The magnetism of the protostar, the forming star,

can actually affect the disk and slow it down

and actually let it drop in and help the star itself form.

The swirling gas in the forming star

and its surrounding disk

generate powerful magnetic fields.

These fields grab the fast-moving particles,

slowing them down.

Bullock: Magnetism works like a cosmic brake.

It slows down a little bit

and eventually spirals into the center.

Gravity stars to win.

Gravity beats out that angular momentum,

and star formation happens.

Gravity drags the slowing disk inwards,

crushing it until the gas gets so dense it ignites.

A star bursts into life.

This is our universe as it looked 12 billion years ago.

The gassy cosmos is filled with flashes

as gravity and magnetism crush clouds of hydrogen gas

to create stars.

Some of the largest of these stars burn through

their hydrogen fuel quickly.

Without the power of fusion,

there's nothing to fight against gravity.

Sometimes this leads to a violent, magnetic death

when the star collapses and implodes in a supernova.

The gassy outer layers of the star blow out into space,

and the core of the star crushes inward,

supercharging its magnetism.

If you look at stars, just about all stars have

strong magnetic fields at their surface.

What happens is that if a star dies and it collapses,

the same amount of magnetic field must still be present.

So if the surface area of the star is decreased

by a factor of 1,000 or 10,000,

then that means that the magnetic field intensity

must increase by that same amount.

As the supernova's core collapses,

the magnetic field's strength keeps building.

At the end of all this, you get a ball 12 miles wide

called a magnetar.

These dense balls have very, very strong magnetic fields.

In fact, the strongest magnetic fields in the universe.

The magnetic field can be more than a trillion times

stronger than the earth's field.

If you got very, very close to a magnetar,

that strong magnetic field might possibly rip you apart

because your atoms just can't stay together

in the vicinity of such a strong magnetic field.

Giant stars with the potential to form magnetars

still exist within our universe.

Scientists know of 23 magnetars within our galaxy today,

and one of these, sgr 1806-20,

located 50,000 light-years from earth,

is the same magnetic monster that unleashed an assault

on the earth in 2004.

The blast was triggered by a starquake.

That's like an earthquake, but it's on a star,

and the crust of the star slipped about this much,

literally about a centimeter,

the width of your finger, but this was far larger

than any earthquake this planet has ever seen,

millions of times stronger,

and the magnetic field is coupled with the matter in it.

So when the crust slipped, so did the magnetic field,

and it launched a blast of energy so powerful

that 50,000 light-years away

it physically affected our planet.

Happily, this occurred halfway across the galaxy.

If this thing had been a lot closer,

the effect on us would have been huge.

A magnetar a couple of light-years from earth

would devastate our planet.

There could be a burst of radiation that could literally

strip away our atmosphere.

Without an atmosphere, there's no air to breath.

Animal life would die.

Without air pressure, the seas would boil away.

Earth would be left as a lifeless ball of rock

spinning through space.

Everywhere we look in the universe,

we see the same stuff following the same rules.

The universe is only made up

of a handful of basic ingredients ...

hydrogen, helium, lithium, carbon and so on.

All of these chemicals, in different proportions,

are what make us up.

And these same chemicals, in different proportions,

make up everything.

The same chemicals that form galaxies and stars

do something amazing on earth, perhaps even unique.

They become living things,

organisms that can grow, reproduce and think.

Durda: We are bits of the universe made conscious.

I think that's a ... it's ... it's a biological miracle.

You look out into the sky, and you know you're connected

to that somehow.

It's pretty fantastic.

So when does the story of life on earth begin?

Actually, it begins long before earth existed.

After the big bang, the universe is little more

than a vast cloud of hydrogen gas.

Then, pockets of the gas cloud collapse to form stars.

And only stars can turn hydrogen

into the more complex molecules that will become planets

and people.

Deep inside the cores of these early stars,

heat and pressure crush hydrogen atoms together

so powerfully they fuse,

creating helium atoms and releasing a burst of energy.

Over time, helium atoms fuse together too, creating carbon,

nitrogen, oxygen and even heavier atoms.

Over hundreds of millions of years,

ancient stars build up all the elements

that make up our solar system today,

including the atoms in your body.

But in doing so, these stars pay a catastrophic price.

Drained of energy, the ancient stars collapse

and then explode in a supernova,

spreading their chemically rich stardust across space.

The iron in your blood, the calcium in your teeth,

in your bones, these were created

in a supernova explosion,

probably different stars that blew up billions of years ago,

seeding the space around them with this stuff.

Blasted through space, these complex atoms

now pepper the clouds of gas that are nurseries of new stars.

And 4.6 billion years ago,

one particular cloud begins to collapse under its own gravity,

and our sun ignites.

Much of the ancient stardust is sucked into the sun,

never to be seen again.

But the leftovers clump together to form comets,

asteroids, planets and eventually life.

I actually think of myself

as a very complicated rock.

I am made of things like iron and copper and manganese.

When you sit down on a mountainside

and you're there with a rock, those are your cousins too.

Thanks to ancient supernovas, the earth forms

with all the atoms needed to create both rocks and life.

But what is it that distinguishes us

from a piece of granite?

Three things ...

a power source, a protective sack,

and the plans for making more protected power sources.

DNA is the plan.

It's a long molecule, built up from small units

called nucleotides.

DNA contains the instructions for how to build the cell's

protein engine using small molecules called amino acids.

DNA also tells the cell how to make lipids,

a fatty molecule that forms a perfect protective sack.

And that's all there is to it.

You have the basic form of life, a cell.

The chemistry set for life is actually quite simple.

It's 20 amino acids.

It's a few nucleotide bases for making DNA and rna,

a few lipids, and that's it.

Think of it as like a lego kit.

A few billion years ago,

when you looked in our solar system,

you might have seen two earths.

Well, a few billion years from now, in the future,

you might look at our solar system

and see two venuses.

So we can look to Venus' past and see our future.

We know that temperatures skyrocketed,

and the scarred surface hints at why.

Hawaii's volcanic lava fields

look like Venus in miniature.

Both produce the same kind of runny lava,

building flat, shield-like volcanoes.

The big difference

is there are only five active volcanoes on Hawaii.

Venus is covered in them.

One thing that really jumps out all around the planet

is the number and variety of volcanoes.

I mean, Venus could almost be nicknamed "volcano world."

Venus has tens of thousands of volcanoes all over the planet.

But it's not the erupting lava

that turns up the heat.

It's what comes out with it.

Up close on the surface,

jani can see the origin of the gases.

If we look behind us,

we can see volcanic gases gushing out of steam vents.

We've got carbon dioxide being delivered to the atmosphere.

It's exactly like what has happened on Venus.

Carbon dioxide has been delivered out of volcanoes

over and over and over again throughout its history

so that now we have

just a tremendously thick, dense atmosphere.

The net result of all of these volcanic gases

pouring out of volcanoes, major greenhouse gases,

is that they have been absorbing heat

for billions of years of the history of Venus.

The temperature has been gradually creeping up

until, today, the surface of Venus is 900 degrees.

It's hard to imagine such extreme temperatures.

But probes orbiting the planet

revealed just how insanely hot it is.

Scientists studying the images

noticed something strange on the planet's mountains.

It looks like, on the mountains,

that there's apparently snow-like structures.

But this is not like

any snow found on earth.

So, if you look at the white-peaked mountains of Venus,

you would think that it was snow,

but it's actually metals that have rained down

and deposited on the top of those mountains.

Metals like bismuth and lead melt.

Then they evaporate into the atmosphere.

As they rise, they cool

until they finally fall like snow on the mountaintops.

I'm not sure even the imagination

of science-fiction authors would have come up

with something as weird as Venus.

I mean, just think about that.

You have possibly metal frost on the top of mountains.

I mean, how weird is that?

It's pretty insane. Raining metals.

Where would you ever think about that existing?

On Venus.

In the future,

metallic snow is forecast for earth, too.

And our scorching mountain caps

will glitter like Venus.

This is the earth half a billion years

after the crust cooled.

The climate is warm and wet,

and the asteroids that delivered the building blocks for life

are a distant memory.

Some simple life may have already taken hold,

but this may not be the life that turned into us,

because the earth is about to be pummeled

by a second wave of asteroids,

and a radical theory called panspermia

suggests some of these space rocks

are filled with alien life.

So panspermia is the idea that life Rose on some other

planetary body or other environment and came to earth

and was delivered by falling debris.

The panspermia argument begins with a game

of cosmic pinball 4.1 billion years ago.

The outer planets of the solar system

haven't yet settled into stable orbits.

They jostle for position.

The gravitational fallout sends a hail of giant asteroids

towards the earth.

It's called the late heavy bombardment.

We're just orbiting the sun, happy as can be,

and the outer planets are throwing

these gigantic objects at us.

And they just kept coming in and kept coming in

and kept coming in.

If delicate organisms

had developed in the early oceans,

the late heavy bombardment would have wiped them out.

But the earth wasn't the only planet in the firing line.

Asteroids also hit Mars,

and back then, Mars was a very different planet.

With an evolutionary head start,

Mars could have developed Hardy bacterial life

by this stage, perhaps living deep within the surface rocks.

We've seen life on earth that are cryptoendolithic,

so they hide in those rocks,

and they survive the radiation and the harsh environment

by hiding and thriving inside of that surface.

A giant impact on the surface of early Mars

could have thrown rocks filled with bacteria high into space.

McKay: These are organisms prepackaged, ready to fly.

You could imagine some of them trapped in a rock,

kicked off a planet, flying through space,

thousands of years later landing on another world,

popping open, and being able to reproduce and grow.

So, did a martian rock seed the earth with life

toward the end of the late heavy bombardment?

It's an incredible possibility.

But how could the Mars bugs have survived the long journey

through space?

Certain bacteria on earth,

when they experience a stressful environment,

they start forming what we call spores.

And spores, if you imagine a seed,

has all of the genetic information in the middle,

and it's protected by numerous layers of defense.

They really seal themselves up in little spaceships,

and that would allow them to survive in space.

You could take a spore, put it in space, bring it back,

and it would still be viable.

Spores also allow bacteria to stay alive in a dormant state

for incredible lengths of time.

The record on earth is a spore that formed

before the age of the dinosaurs

and was recently resurrected after a 250 million-year nap.

You know that ... that spores can survive in theory

for millions and millions of years,

but to actually see evidence of a spore being revived

is pretty fantastic.

The final hurdle for panspermia

is the fiery touchdown on the surface of the earth.

Planetary scientists simulate violent impact events

with high-speed guns to see if martian bacteria

could have survived.

Not every bit of the projectile is destroyed

and highly shocked in an impact.

When we do these experiments, we often find little bits

of the projectile left over in the impact chamber.

If there are bacteria living in that portion of that rock,

they could potentially survive the impact back onto the planet.

The science shows us that panspermia is possible,

but does it take us any closer to understanding

the origins of life?

The fundamental problem with panspermia is that

it's just removing one step of the problem

and putting it someplace else.

We don't know how life originated on earth.

Now it's going to originate on Mars,

but we don't know how it originated on Mars.

So you still have this basic problem, and that is,

how did life start?

Did our ancestors arrive from space,

or did they rise up from the oceans of the earth?

Pushing atoms together so strongly they stick

is called nuclear fusion.

It's the first step for turning a universe full of gas

into one filled with the ingredients for planets,

people, and cars.

So, how do you get two atoms to fuse?

This guy's been doing it in his garage since he was 14.

Taylor Wilson is obsessed with nuclear fusion.

Yeah, the neighbors know about the radioactive stuff

that's in the garage.

And so does the government.

It's all relatively low level.

That's my watch going off.

I think I'm the only person I've ever met

with a geiger-counter watch.

The centerpiece of Taylor's nuclear man cave

is this precision-engineered fusion reactor,

which he built when he was still in high school.

Okay, I'll let in some gas now.

The first ingredient ... hydrogen gas.

And it will be flowed into the chamber through this very

precise sapphire leak valve.

The next ingredient ... high-voltage electricity.

Taylor passes a high voltage

through a small, spherical cage

that sits inside the reactor.

The negatively charged cage

quickly draws the hydrogen ions inside it.

So it's taking all those ions

and sucking them towards the center.

And as they fly in they get confined,

and hopefully they collide with each other and fuse.

The temperature of the atoms inside the cage is now so great

that hydrogen atoms are fusing together,

creating heavier helium atoms and a burst of energy

hotter than the surface of the sun.

It's that little, tiny blob of plasma inside those grid wires

that's kind of like a star in a jar.

13 billion years ago,

the universe uses gravity to fuse atoms

instead of an electrical cage.

Across the cosmos, vast clouds of hydrogen gas

collapse under their own gravity.

Pressure and temperature build

as more and more gas gets sucked in.

Eventually, fusion sparks deep in the core

of these giant balls of gas,

and the first stars start to manufacture

many of the heavy elements that make up your car today.

Deep in the outer reaches of the solar system,

far beyond the last gasps of the sun's atmosphere,

we are blind.

We simply can't see that far.

But sometimes we get messengers from beyond,

potentially life-ending messengers ... comets.

There's basically two kinds of comets.

There's comets that are called short-period comets,

and the other kind is called long-period comets.

Short-period comets come from the kuiper belt,

the disk of space junk just beyond the planets.

They travel around the solar system

in relatively small circles,

returning at regular intervals of 200 years or less.

Long-period comets are a bit more mysterious.

The long-period comets can come back around

something like every 1,000 years,

or even a million years,

and unlike the short-period comets

that come in on sort of circles,

the long-period ones come in on really plunging orbits,

and they can come in

from all over the place and all different directions.

And that tells us they come from somewhere different.

The long-period comets we think are coming from someplace

much, much farther away,

and it's more like a spherical cloud

of very distant things

that are now plunging down into the sun every now and again.

When a comet comes in, the sun heats it up.

The ice turns into a gas, and the comet loses mass.

Over time, these comets will disappear,

and yet they keep coming.

That means that there must be a reservoir of them out there.

But where is there? Where are they coming from?

One of the first explanations for these strange comets

is maybe they're not from our solar system.

Maybe the galaxy is full of these icy chunks

that occasionally rain down on us.

But then we thought,

"maybe they come from another part of the solar system."

Maybe our whole solar system was surrounded

by a ball of junk left over

from the very first days of its creation ...

the oort cloud.

It was theorized that there must be a reservoir of them,

a giant cloud surrounding the solar system, with millions,

billions, maybe even trillions of these icy bodies.

But we've never actually seen it.

So this oort cloud,

this theorized population of comets, is that ...

it's theoretical.

It's never been directly observed.

The objects in the oort cloud are so far away

and so small and dark

that we've never observed something

actually out in the oort cloud.

Something has to fall in.

So you see things falling in

from all of these different angles.

From there, you can deduce what must be out there.

A fun way to think of the oort cloud

is that these are pieces of planets that never got used.

They really are leftovers.

The oort cloud actually didn't come with the original package,

if you will.

The oort cloud formed when they tried,

but miserably failed, to join the party

and become those giant planets,

and instead got thrown all in different directions,

and they now exist halfway to the next star.

They're a big, giant spherical distribution.

4.6 billion years ago, our sun ignites.

A cloud of dust and gas circles the infant star.

Then gravity gets to work,

sucking in gas, dust, ice, and rocks

to form the infant planets.

The planets formed out of building blocks,

smaller chunks of material ... rock, ice...

Stuff that came together over time.

The frenzy of swirling, colliding matter

leaves behind debris as rocky rubble in the asteroid belt

and ice in the kuiper belt.

Then Neptune and uranus got in on the act,

scattering the debris out further.

Most of them go thrown out of the solar system forever,

but the ones that didn't

go on these big, long, million-year looping orbits,

and that's the oort cloud.

Billions of icy rocks

were thrown out in all directions

until a ball of debris formed around the whole solar system.

The oort cloud comets

are dinosaur bones of solar system formation.

Contained in them are the ingredients

that went up to make our planets.

Most of the oort cloud objects

will stay in this icy cloud forever,

orbiting the distant sun.

But a few get nudged loose,

and the sun's gravity pulls them inwards like moths to a flame.

And such a comet could sneak up on you,

and you won't even know it's there.

These comets can be many miles across,

and they're moving extremely rapidly,

sometimes as much as 100 miles per second.

This makes them pretty dangerous.

How dangerous? Ask a dinosaur.

Some people think that the massive impact

that killed off the dinosaurs

may have been caused by a huge oort cloud comet.

They can be every bit as dangerous

as the asteroids usually blamed for extinctions on earth.

We'd have little or no warning because we have no idea what

is hurling stuff out of the oort cloud at us.

For over 4 billion years,

the earth and the moon have traced

a delicate dance around the sun.

But our celestial partner is gradually slipping away.

Sometimes, we talk about things that are reliable.

We say there's nothing as reliable

as the rising of the sun, right?

We can think of the moon in the same way.

It goes through its phases.

It's there night after night, year after year.

But it turns out the moon is actually

moving away from the earth, and that's due to

the interaction of the moon and the earth's tidal bulge.

The bulge of water pulled up by gravity

sits slightly ahead of the moon

because the earth spins faster than the moon orbits.

The moon pulls by gravity on that bulge

and slows the earth's rotation.

Over billions of years,

that has slowed the earth's rotation a lot.

We used to be spinning a lot more rapidly,

probably more than twice as fast as we do now.

But, like a gravitational whipline,

the moon's attraction to the bulge also speeds up its orbit.

This speed makes the moon's orbit wider,

pushing it farther and farther away.

It's a very small amount, so it's only about

3.8 centimeters, which is about an inch and a half a year.

Over billions of years,

the moon will shrink to a dot in the night sky,

and the earth's spin will become so slow

that the moon will appear to freeze above our heads.

There will come a time where the earth is actually locked.

One side of the earth faces one side of the moon,

and the two of them will go around in lockstep.

So there'll be one place on earth

where you can see the moon.

So you might imagine you'd have to go on some kind of, uh,

vacation to actually see the moon at that point in time,

but that's gonna be a long time from now.

So ... so, you know, um, I wouldn't start booking

your tickets quite yet.

Is this the long-term future of our moon?

Some scientists envision a more dramatic ending ...

a death by fire that will destroy the moon

and, quite possibly, all life on earth.

The process begins with the expansion of the sun.

The actual future history of the earth-moon system

will depend upon the sun,

and it could produce remarkable effects.

As the sun gets older, it expands,

filling the inner solar system with a denser solar wind.

This wind will impede the moon.

So as the moon orbits around the earth, there'll be drag.

There'll just be more stuff in space

for the moon to push against.

So the moon has been moving away from the earth

for billions of years.

Maybe at that point, it'll start coming back.

This new inward trajectory is a death spiral.

The moon eventually is going to spiral

closer and closer, and then,

because of the gravitational forces,

the tidal forces are going to be so strong, it's going to,

essentially, explode.

The moon, 11,000 miles above the surface of the earth,

reaches a point of no return.

The gravitational pull of the earth finally overwhelms it.

The fractured remains of the moon

create a saturn-like ring of rocky debris.

Having a ring around the earth would be a phenomenal sight.

I would love to see that.

You would look up, and you would be able to see the ring.

It would be at an angle to the earth.

If you were at the right place on the earth,

you'd be able to see it, broad, stretching across the sky.

I don't know if you'd be able to see it during the day,

but at night, it would be

one of the most spectacular sights I can imagine.

But the beauty soon turns to terror,

as pieces of the ring rain down on earth.

I mean, it's gonna be an awesome sight,

a terrifying sight.

I mean, the whole sky is going to be filled

with raining meteors just showering through the sky,

and they're gonna be huge.

Radebaugh: Eventually, all of that material

will be incorporated into the earth, and now,

these two siblings, separated at birth,

now are finally again one body.

More than 9 billion years

after the big bang, our sun and our planet, earth, is born.

Slowly, we're piecing together the complex connections

that bind it to our lives and to the universe beyond.