How the Universe Works (2010) s03e06 Episode Script
Weapons of Mass Extinction
We live on a volatile planet in a violent universe The universe constantly wants to kill us.
where planets collide.
The entire surface of the Earth is liquefied that was literally a vision of hell.
Black holes blast out invisible death rays.
It would be apocalyptic beyond apocalyptic.
Asteroids strike without warning.
It is a real possibility that it could happen in the next 10 minutes.
These cosmic killers have struck time and time again, wiping out entire species, and pushing life on Earth to the edge of oblivion.
It's happened before.
It's gonna happen again.
And our species could be next.
There will be disasters in the future, and one of them will destroy us.
captions paid for by discovery communications not too hot, not too cold With water Oxygen.
Our peaceful, plentiful planet nurtures and protects us But this lull won't last forever.
There are dangers all around and trouble ahead.
When we look around, we think that the universe is rather gentle.
We have warm breezes and mild seasons.
Actually, the universe is violent.
It is chaotic.
The universe is not a happy, safe place.
There are asteroid impacts, and solar flares, and supernova, and black holes, and colliding galaxies, and all these really amazingly dangerous and violent events.
And the Earth is in the cross hairs.
During the planet's these violent phenomena have wiped out millions of species in a series of catastrophic mass extinctions.
Mass extinctions due to impacts and other geologic natural processes on the Earth have actually wiped out more species of plants and animals on the planet than exist today.
Mass extinctions are what happens, it just happens periodically, and we living in the quiet time between mass extinctions.
It's happened before.
It's gonna happen again.
The clock is ticking.
With every day that passes, the next mass extinction gets a step closer, and with every new discovery, the universe gets a little bit more terrifying.
November 2012.
Astronomers identify a new planet at least four times more massive than Jupiter, and it's gone rogue.
Unlike Earth and all the other objects in our solar system, this planet doesn't orbit a star.
It really is lost in space.
When I was a kid watching science-fiction movies, every now and again there would be a rogue planet, just some planet wondering space without a star.
And I thought that was pretty silly, but it turns out that might actually happen.
When planets are forming, they can interact with each other gravitationally.
And it's entirely possible that when our solar system formed, planets were kicked out into interstellar space.
There could be as many as 200 billion rogue planets in our galaxy.
That's as many rogue planets as there are stars in the sky.
And one of them could be heading our way.
A collision with another planet sounds farfetched.
Could it really happen? As a matter of fact, it already has.
a young planet veers into the Earth's orbit.
We have the Earth sitting here, and another planet about the size of Mars came in and smacked us hard.
The two collided over 25,000 miles an hour, The impact destroys the smaller planet.
The Earth survives, but only just.
The violence of this is hard to imagine.
Two planets coming together smashing together into one molten mass.
After an impact of that scale, the entire surface of the Earth is literally liquefied.
Imagine the floor of an active volcano with islands of solid rock and lava spurting right and left.
The entire surface of the planet would've looked like that.
The Earth itself for a little while would've had an atmosphere of molten rock.
And it was a, you know, vision of hell.
Debris blasted out at 20,000 miles an hour orbits the molten Earth.
Gravity brings the debris together.
The result -- our moon.
Our moon emerged from the wreckage of the most cataclysmic event in our planet's history.
From destruction comes creation, because without this lump of cosmic shrapnel, life on Earth might never have gained a foothold.
The moon's gravity pulls on the infant Earth's oceans, spreading nutrients from the land into the water.
And it slows the Earth's spin from a 6 to a 24 hour day.
In this calm, fertile environment, one billion years after the impact, life begins.
If we hadn't had that planetary collision a long time ago, we wouldn't have the moon today.
So, in fact, this most catastrophic event you can possibly think of actually may have helped life on Earth form in the first place and helped us evolve over the next couple of billion years.
But what was a good thing in the past would be a disaster if it happened today.
Now, you don't want a planetary collision now because that would wipe out the entire planet.
You can't even describe it comparing it to nuclear weapons.
It would be billions of nuclear weapons.
It's enough to melt several miles thick crust on the Earth all the way down.
It would wipe out all life on Earth.
That would be it.
It would be like a hard restart for the planet itself.
Could this nightmare become a reality? Right now even the closest rogue planets we've discovered are still trillions of miles from Earth.
And our neighboring planets have settled into calm, stable orbits.
We're not gonna get a planetary collision any time soon, but all the gravity of the planets play with each other and change each other's orbits.
So clearly if you run the clock work of time forward billions of years, yes, it's entirely possible that we might have another planetary collision.
You just don't have to worry about it for a long, long time.
a devastating collision made life on Earth possible.
that life threatens to destroy itself.
Our blue planet -- in a hostile universe, it sustains and nurtures life.
simple, single-celled organisms drift through the nutrient-rich oceans.
But their world is about to be destroyed.
When you talk about mass extinctions, you have at least two types -- one danger coming from outer space, another from our own very backyard on the planet Earth.
The Earth circles the Sun, but this orbit is unstable.
Over hundreds of thousands of years, it changes, swinging the planet further out into space and pivoting on its axis.
Tilted away from the Sun, the Earth cools.
something turns this natural cooling into a global catastrophe.
It is one of the most dangerous things in all the universe life.
Tiny organisms populate the oceans.
There's no oxygen around and that's the way most of them like it.
But then a new kind of bacteria evolves -- cyanobacteria.
And these guys create a serious gas problem.
Imagine Earth billions of years ago.
There's no oxygen.
Everybody's happy.
Then cyanobacteria start making oxygen.
It's a toxic pollutant.
If there was a regulatory agency at the time, they would've been outlawed.
Eventually they polluted the whole world.
They had really precipitated an ecological crisis of global proportions.
The great oxygen crisis upsets the greenhouse effect that keeps the planet warm.
Global temperatures plummet.
The ultimate culprit is biology.
Biology makes a mess of the planet, produces oxygen.
The oxygen destroys the greenhouse effect of methane and that freezes up the Earth.
ice creeps out from the poles.
Instead of warming the planet, sunlight bounces off the ice, temperatures fall, creating more ice which bounces more sunlight back into space, and so on and so on until the cooling becomes unstoppable.
The ice marches on.
Temperatures plunge.
The blue planet turns white.
It's a snowball Earth.
And incredibly, this may've happened not once but at least three times over the following billion years as the planet lurched around the Sun.
But throughout all of this and against all the odds, a handful of species clung to life, thanks to volcanoes.
Even in an Earth that was covered almost entirely by ice, volcanoes would've been punching through that.
So you certainly have pockets of water lying about.
And life was able to carry on and get through these cold periods.
And the whole time, the volcanoes that help sustain life have been pumping out carbon dioxide.
As this greenhouse gas increases, the atmosphere warms.
Until 640 million years ago, the last, great snowball Earth ends.
And the survivors emerge into a new world.
After snowball Earth goes away, things get very interesting.
A lot of opportunities open up for life, water's flowing, ice is melting, organic material built up that hasn't been decomposing.
So you can imagine that there will be a burst of development.
In the meantime, cyanobacteria have been churning out ever more oxygen.
Other organisms will either learn to breathe it or die.
Many organisms decided that this poison could be useful, it's energetic, and that allowed them to have an energy source that was so powerful that they could build huge, complex structures -- poof, animals.
Snowball Earth is an environmental disaster and an evolutionary triumph.
Complex life flourishes.
But most of these creatures will never evolve beyond this point.
Something stops them dead.
It is the most powerful weapon in the universe, and it strikes in the blink of an eye.
In a violent universe, against all the odds, life survives.
But consider this -- at any moment, the universe could pull the trigger on a secret, deep-space death ray, obliterating all life on Earth.
And until the 1960s, nobody even knew it existed.
- the height of the cold war.
The United States and Soviet union raced to outgun each other, stockpiling and testing nuclear weapons.
America was worried that the Soviet union would be able to test nuclear weapons in space.
So what America did is launch the series of satellites to go out into space and look for the tell-tale flash of gamma rays from nuclear tests.
On July 2, 1967, the satellites detect a burst of gamma rays, the most energetic and destructive form of electromagnetic radiation.
Immediately there was panic in the Pentagon.
Perhaps the Russians are testing super-gigantic hydrogen bombs in outer space.
And we're just caught flat-footed.
But it's not bombs.
It's something far deadlier.
And then the realization sunk in.
"Oh, my god.
"These flashes are coming from outside the milky way galaxy.
They must be billions of light-years away.
" A new source of energy, second only to the big bang itself had been discovered.
When gamma ray at first were first discovered, people assumed that they must be fairly close by.
"Of course they have to be close by.
They're the brightest thing that we see in the sky.
" And now we know that gamma ray burst, not only are they not nearby, they're not in our galaxy, they're not in nearby galaxies, but they're close to the edge of the universe.
They're as far away as anything else that we observe, and that's completely ridiculous.
Over distance, light gets dimmer.
The further light has to travel, the dimmer the light should be.
If light from a distant galaxy comes to Earth and it has gamma-ray energies, then that explosion must've been incredibly powerful, because it turns out that as light travels through space, the wave length of the light gets stretched out.
And this stretching caused the light to lose energy.
And since the light rays have traveled a very great distance through the cosmos to reach us, and they're still gamma rays, they must've started out with a great deal of energy.
And the amount of energies are unbelievable.
You're talking about the entire energy budget of the Sun over its whole lifetime emitted over the course of just a few seconds.
These are amazingly violent, amazingly powerful events.
In June 2008.
NASA launches the Fermi space telescope.
Its mission -- discover the source of these huge blasts.
What Fermi does is open our eyes to the universe that's there but gives us such a different view that we really get a deeper and greater understanding of what's going on.
If you had gamma-ray eyes, the milky way would be blazingly bright across the center of the sky.
Your vision would be dominated by these very dense, pulsing stars and super-massive black holes.
And it's black holes that may solve the mystery of gamma-ray bursts.
When a truly gigantic star dies, one at least 25 times more massive than our own sun, it collapses to form a black hole.
Scientists believe black holes are one of the few things in the universe large enough and powerful enough to generate gamma-ray bursts.
Gamma-ray bursts are the birth cries of black holes.
When a massive star explodes and becomes a supernova, the core collapses and forms a black hole.
Material falls around it, swirls into a huge disk, it gets incredibly hot.
As it's falling into the black hole it forms a tremendous magnetic field, as well.
The remains of the star spiral towards the black hole.
Enormous electromagnetic forces fling some of this matter outwards.
Hurtling up and down the black hole's huge magnetic fields, the matter collides with debris from the initial explosion, accelerating to close to the speed of light, heating to millions of degrees.
These high-speed collisions unleash unimaginable amounts of energy.
This is the gamma-ray burst.
Gamma-ray bursts are fascinating.
You can study them throughout the universe because they're so bright.
But if you move them in really close to the Earth, let's say within they become extremely destructive.
The beams are so huge that if a gamma-ray burst occurs, say, by the time it reaches the Earth, the beam will be wide enough to engulf our entire solar system.
Basically, if you were standing on the Earth and you looked up, you would see a flash of light, and before you could even say, "what's that?" You'd be gone.
The amount of energy in the beam that travels across space is so intense it would basically light the Earth on fire from that distance.
It would strip off the Earth's atmosphere, it would boil the oceans, it would melt the rock.
It would be apocalyptic beyond apocalyptic.
This is the worst-case scenario.
But what if a gamma-ray burst hit the Earth from further out? Would we survive? People ask what would happen if there was a gamma-ray burst within 6,000 light-years of the Earth.
It's actually not the right question.
There have been gamma-ray bursts that close to the Earth, and there probably have been extinctions of life on Earth due to gamma-ray bursts.
after snowball Earth, the oceans are teeming with complex life.
But 440 million years ago, And the killer may have been a single devastating gamma-ray burst.
The blast penetrates the oceans' upper layers, killing the creatures that live near the surface.
Creatures living further down survive the initial onslaught, but not for long Because the blast also damages the Earth's ozone layer, exposing the planet to the Sun's deadly uv radiation, triggering acid rain and lowering global temperatures.
Over half a million years, the creatures that survived the gamma-ray burst get taken out by its after effects.
If a gamma-ray burst has wiped out life in the past, it could happen in the future.
And astronomers think the next burst could come from a dangerously unstable star, wr 104.
Wr 104 is the nightmare.
We now have a potential candidate for what may become a gamma-ray burster with our name on it.
We are literally staring down the gun barrel of wr 104.
It's not one but two massive stars orbiting each other.
The stars will die in a massive explosion, spawning a black hole, and blasting out gamma rays.
The object is about 8,000 light-years away, so we are within the kill radius of this object.
So you could be doing your laundry tomorrow, look up in the sky, and all of a sudden, there's this burst of radiation raining down from the heavens.
The radiation rips off the Earth's ozone layer, creating a toxic smog and exposing us to the Sun's deadly rays.
Life as we know it could cease to exist.
Plants would be scorched, animals, which depend upon plant life, will then begin to die.
Human civilization would have to go underground.
It may sound like the death star destroying the Earth in "star wars," but the difference is the death star isn't gonna happen, a gamma-ray burst might.
Our extinction could happen at any time.
And the fatal blow doesn't have to come from space.
It could come from the very thing that makes life possible - - the Earth itself.
Our planet conceals a weapon of mass extinction, primed to detonate at any moment, hidden deep beneath our feet.
Unleashed, the heat inside our planet could wipe out everything in its path on a massive scale.
after a gamma-ray burst may have devastated life in the oceans, the survivors have colonized the land.
Among them, a motley crew of monster reptiles - - scutosaurus and gorgonopsians.
They're successful, strong, and doomed.
Around about the biggest mass extinction that the Earth has ever seen, the end-permian extinction.
Just over 90% of marine fauna and around about 70% of land fauna disappeared from the planet.
The killer is a volcanic eruption -- the biggest and most catastrophic the world has ever seen.
in what is now Siberia, the Earth's crust ruptures, pushed beyond breaking point by a vast plume of hot magma surging up from deep inside the planet.
The Earth itself can internally generate some very devastating events, millions-of-years-long events in the form of major volcanic eruptions at the continent-scale level.
These are basaltic-volcanism events that flood entire portions of the planet with basalt lava.
Lava spews for two million years.
There's enough lava to cover the entire United States beneath a thousand feet.
And the death toll extends around the Earth and deep into the oceans.
The question is why.
The answer lies with the most volcanic country on Earth -- Iceland - with a similar, smaller eruption just 230 years ago.
June 1783.
A terrible chain of events unfold that will devastate Iceland and kill up to a million people around the world.
Near the village of laki, a 17-mile-long tear opens up in the Earth's crust.
These holes and cracks in the ground that you can see, they would've had jets of magma, jets of lava flying up into the sky.
To give you an idea of scale, the overall the amount of material that came out of laki is about 3 1/2 cubic miles of volcanic material, and that's a lot material.
And it's not just the size of laki that makes it so special, it's actually what's inside this and what came out of this that's the dangerous thing.
Because it had lots of sulfur gases associated with the eruption and also lots of fluorine, quite poisonous gases.
Sulfur dioxide spreads out around the atmosphere.
Its droplets form a giant mirror reflecting the Sun's warmth away from the Earth.
It's clear that even a relatively small eruption like laki can cause big, dramatic effects in terms of the climate.
In the northern U.
S.
, there was one of the coldest winters ever recorded.
In fact, the Mississippi is recorded to have frozen.
It's been implicated in causing the big famine in Japan.
So, the effects, potentially, for volcanoes that spew these horrible gases into the atmosphere can be catastrophic on a global scale.
Now picture the siberian eruptions They're 200,000 times larger than laki and last a million times longer.
They release massive quantities of gas triggering extreme climate change -- first cooling, then heating the atmosphere.
land-based creatures die, including the mighty gorgonopsians and scutosaurus.
But worse is to come.
As the oceans warm, they lose oxygen and stagnate.
Toxic algae takes over, poisoning the oceans with hydrogen sulfide, killing 96% of marine life, and leaving purple sulfur bacteria to overrun the oceans, turning the water pink.
This is the closest the Earth has ever come to total extinction.
But over 200 million years, the survivors adapt and evolve.
A new group of animals emerge.
They are the largest, most successful creatures the Earth has ever seen - - the dinosaurs.
But they, too, will face annihilation.
Cosmic killers prowl the universe threatening to wipe out life on Earth.
They've struck before, pushing life to the edge of extinction.
They will strike again, and it could happen before you've finished watching this show.
February 15, 2013.
It's another cold winter's day in the siberian city of chelyabinsk when literally, out of the blue A 14,000-ton, 65-foot meteor tears through the atmosphere at 42,000 miles an hour.
It explodes in the air unleashing a powerful blast wave, shattering windows, damaging 7,000 buildings, and injuring 1,500 people.
Now imagine what would've happened if the asteroid had hit the Earth in one piece.
And we saw what happened over Russia, over in chelyabinsk, with an object that could have hit the Earth -- could've hit the Earth with a force of perhaps 20 Hiroshima bombs.
If you watch those videos of that meteor in Russia with the incredible Sonic boom, you could see how even a small object -- relatively small in a cosmic sense -- could produce a dramatic event for humans.
The way it works is small objects are hitting the Earth every day, large objects, every week, larger objects still, every year.
And an object the size of the chelyabinsk meteor strikes, on average, once every century.
So when the next big one strikes -- not if what will happen? The clues lie in the past in the extinction of the dinosaurs.
About 65 million years ago, there was a perfect morning on Earth.
I would've loved to have been there to see the giant dinosaurs, you know, the pterodactyls flying through the air, all of that.
And then something changed, and the Earth would never be the same.
If you would've looked into the sky, you would've seen a relatively dim light at first coming towards you, getting brighter and brighter, and hotter and hotter.
It's a six-mile-wide rock the size of mount Everest racing towards the Earth at 25,000 miles an hour.
The first wave of destruction would've started before this object even hit.
There would've been shock waves, heat, and winds going across the entire planet.
Everywhere that was under the path of this asteroid would've been seared, set on fire.
The oceans would've been boiling underneath it.
The asteroid smashes into the ocean off of what is now Mexico's Yucatan peninsula.
It strikes with a force two million times greater than the biggest nuclear bomb ever detonated, and blasts out a crater A super-heated shock wave roars out at twice the speed of sound.
soar to the edge of space.
Two hours after impact, a 300-foot Tsunami smashes into the coast of what is now the U.
S.
A.
Reaching as far as North Carolina.
Over the next few hours and days, the debris rains down, setting the planet ablaze.
In the following weeks and months, smoke from the fires adds to the dust blasted into the atmosphere.
There was so much pulverized rock, all of the burning materials up into the atmosphere, you wouldn't have been able to see the surface.
And on the surface, you wouldn't have been able to see the Sun, and it was like that for a long time.
This ancient apocalypse is a disaster for the dinosaurs but without it, we wouldn't be here.
Back then, during the time of the dinosaurs, our ancestors were probably little, furry mammals that were an evening snack for a dinosaur.
When the dinosaurs got wiped out, these small, little, furry mammals began to expand in size to take over the niche left over by the dinosaurs.
So, one life-form replaces another life-form, in this continual process called survival of the fittest.
We are here because our ancestors survived the extinction event, and, in fact, flourished because of it.
From our point of view, that extinction event was a good thing, but we're here for a brief moment.
And there will be disasters in the future, and one of them will destroy us.
There is a 1 in 5,000 chance that an asteroid, the same size as the dinosaur killer, will strike within the next 100 years, and it could happen at any time.
It is a real possibility that it could happen in the next 10 minutes, but is a tiny possibility.
So, I always say, "you don't need to prepare very much "for winning the lottery, you know.
"You may have a similar chance to getting taken out by an asteroid in the next 15 minutes.
" April 2014.
Scientists make a shocking announcement -- since the year 2000, in the Earth's atmosphere, each one with the force of a nuclear blast, with some up to 40 times more powerful than the Hiroshima bomb.
And we didn't spot a single one of them before they struck.
Even if we had the technology to detect an asteroid before it hit us, could we destroy it in time? The Hollywood favorite, of course, is to go out there and nuke it, blow it to smithereens, right? That could actually work in the case of some particular, you know, last-ditch effort for asteroids of just the right size.
But a nuclear bomb could just make a bad situation worse.
Transforming an asteroid into large radioactive chunks that rain down all over the planet.
But there are also techniques, like shining a laser on the asteroid or sunlight, which would create an artificial cometary jet, if you will, would vaporize some of the water and the minerals on the surface of that asteroid to gently push it off to the side.
Another fantastic technique, a very robust one, is something we call the gravity tractor.
You just park a spacecraft, the mass of a communication satellite, next to that small asteroid and use the thrusters on the spacecraft to keep it hovering just off the surface of the asteroid, and that uses then gravity between the two as a tow line to move the asteroid ever so gently off course.
Right now these technologies are still on the drawing board.
If they do become a reality, we'd still need months or years to prepare.
Rogue planets, ice ages, gamma-ray bursts, volcanic eruptions, and asteroid strikes.
We've survived the worst the universe can throw at us, but our species will still face extinction.
It's as inevitable as the Sun rising.
In a cosmic battle to the death, we are the survivors, but eventually the universe will win and we will face extinction Threatened by the very thing that gives us life -- our creator, the Sun.
We orbit a giant nuclear bomb, the Sun, but, you know, it's not going to explode.
It's too small to explode, but what happens with the Sun is that every day, it's a little bigger than it was the day before.
Since the Sun's birth, hydrogen has been fusing into helium in the Sun's core.
As the helium accumulates, the core gets denser.
With 150 million tons of helium squeezing into the core every second, the gas compresses and heats up.
Right now the temperature inside the Sun's core is 27 million degrees, and its getting hotter all the time.
What happens when you heat up a gas? It expands, and so that's what the Sun is going to do.
As the Sun swells, it will appear brighter.
In 2 billion years, the Sun will be about 15% brighter and that will lead if the Earth remains in its present orbit inevitably to a runaway greenhouse effect.
The oceans will evaporate, and the surface temperature of the Earth could easily be a 1,000 degrees.
So, if we don't do anything, in 2 billion years, we'll be toast.
If we're still here on Earth, we'll perish.
Other tougher species may find a way to adapt and survive, but they'll be living on borrowed time.
It's gonna fill up the sky.
From horizon to horizon, the sky will literally be on fire.
the Sun runs out of hydrogen and enters the final apocalyptic stage of its life, bloating to 100 times its current size.
Our life-giving sun is now an angry, red giant.
The red giant stars are so big they will actually eat up their own planets.
We know of the examples of red giants that go all the way out to where the orbit of Jupiter is in our solar system.
The sun will not get quite that big, but it'll probably get about out to Mars.
And eventually, in fact, the Sun will be so large that the Earth will be located inside of the Sun, which certainly won't be a very pleasant place to be.
The red giant's bloated body absorbs the Earth, incinerating our planet until its nothing more than gas and dust inside a dying star.
The death of the Sun is the ultimate mass-extinction event.
There's 100% chance it will happen.
A 100% chance it will destroy our planet and any life left on it.
But life on Earth may not be the only life in the solar system.
As the Sun brightens, you can imagine a wave of habitability going out.
So right now it's on Earth, it'll go to Mars, and it'll go to Jupiter, and its moons.
Scientists think Jupiter's moon europa may already harbor alien life in a deep, liquid ocean beneath its frozen crust.
But out at Jupiter, it'll be much warmer but not so warm that it would destroy everything.
So even when the Earth is gone, if there's life on europa, it may be able to endure that.
But will our species go on? Can we survive the loss of our home planet? The universe is like an ecosystem -- living things are gonna survive based on the law of survival of the fittest.
What decides if you're fit in this universe is if you're able to leave your planet and go out and populate other planets.
So the only species that are gonna live on forever are the ones that leave their planet.
We can't control the universe, but we may be able to control our fate.
Inevitably, in the long term, the Earth is gonna become uninhabitable.
It's just the way the universe works.
It wasn't made for us, it doesn't care that we exist, and it won't care when we go away.
The only people who care about that are us, and we might be able to do something about it.
In that sense, we have a fighting chance.
Our intelligence is our greatest asset.
It's the end result of four billion years of extinction and evolution.
And it may give us a chance to do something that no other species has ever done before -- break the cycle of creation and destruction and live on.
Everything that you and I are is a consequence of the way the universe works.
The universe is violent, the universe is dynamic, it's constantly pushing us to change.
And here we are, these incredibly evolved, interesting creatures.
We're a direct consequence of the violence, which, in turn, was our creation.
where planets collide.
The entire surface of the Earth is liquefied that was literally a vision of hell.
Black holes blast out invisible death rays.
It would be apocalyptic beyond apocalyptic.
Asteroids strike without warning.
It is a real possibility that it could happen in the next 10 minutes.
These cosmic killers have struck time and time again, wiping out entire species, and pushing life on Earth to the edge of oblivion.
It's happened before.
It's gonna happen again.
And our species could be next.
There will be disasters in the future, and one of them will destroy us.
captions paid for by discovery communications not too hot, not too cold With water Oxygen.
Our peaceful, plentiful planet nurtures and protects us But this lull won't last forever.
There are dangers all around and trouble ahead.
When we look around, we think that the universe is rather gentle.
We have warm breezes and mild seasons.
Actually, the universe is violent.
It is chaotic.
The universe is not a happy, safe place.
There are asteroid impacts, and solar flares, and supernova, and black holes, and colliding galaxies, and all these really amazingly dangerous and violent events.
And the Earth is in the cross hairs.
During the planet's these violent phenomena have wiped out millions of species in a series of catastrophic mass extinctions.
Mass extinctions due to impacts and other geologic natural processes on the Earth have actually wiped out more species of plants and animals on the planet than exist today.
Mass extinctions are what happens, it just happens periodically, and we living in the quiet time between mass extinctions.
It's happened before.
It's gonna happen again.
The clock is ticking.
With every day that passes, the next mass extinction gets a step closer, and with every new discovery, the universe gets a little bit more terrifying.
November 2012.
Astronomers identify a new planet at least four times more massive than Jupiter, and it's gone rogue.
Unlike Earth and all the other objects in our solar system, this planet doesn't orbit a star.
It really is lost in space.
When I was a kid watching science-fiction movies, every now and again there would be a rogue planet, just some planet wondering space without a star.
And I thought that was pretty silly, but it turns out that might actually happen.
When planets are forming, they can interact with each other gravitationally.
And it's entirely possible that when our solar system formed, planets were kicked out into interstellar space.
There could be as many as 200 billion rogue planets in our galaxy.
That's as many rogue planets as there are stars in the sky.
And one of them could be heading our way.
A collision with another planet sounds farfetched.
Could it really happen? As a matter of fact, it already has.
a young planet veers into the Earth's orbit.
We have the Earth sitting here, and another planet about the size of Mars came in and smacked us hard.
The two collided over 25,000 miles an hour, The impact destroys the smaller planet.
The Earth survives, but only just.
The violence of this is hard to imagine.
Two planets coming together smashing together into one molten mass.
After an impact of that scale, the entire surface of the Earth is literally liquefied.
Imagine the floor of an active volcano with islands of solid rock and lava spurting right and left.
The entire surface of the planet would've looked like that.
The Earth itself for a little while would've had an atmosphere of molten rock.
And it was a, you know, vision of hell.
Debris blasted out at 20,000 miles an hour orbits the molten Earth.
Gravity brings the debris together.
The result -- our moon.
Our moon emerged from the wreckage of the most cataclysmic event in our planet's history.
From destruction comes creation, because without this lump of cosmic shrapnel, life on Earth might never have gained a foothold.
The moon's gravity pulls on the infant Earth's oceans, spreading nutrients from the land into the water.
And it slows the Earth's spin from a 6 to a 24 hour day.
In this calm, fertile environment, one billion years after the impact, life begins.
If we hadn't had that planetary collision a long time ago, we wouldn't have the moon today.
So, in fact, this most catastrophic event you can possibly think of actually may have helped life on Earth form in the first place and helped us evolve over the next couple of billion years.
But what was a good thing in the past would be a disaster if it happened today.
Now, you don't want a planetary collision now because that would wipe out the entire planet.
You can't even describe it comparing it to nuclear weapons.
It would be billions of nuclear weapons.
It's enough to melt several miles thick crust on the Earth all the way down.
It would wipe out all life on Earth.
That would be it.
It would be like a hard restart for the planet itself.
Could this nightmare become a reality? Right now even the closest rogue planets we've discovered are still trillions of miles from Earth.
And our neighboring planets have settled into calm, stable orbits.
We're not gonna get a planetary collision any time soon, but all the gravity of the planets play with each other and change each other's orbits.
So clearly if you run the clock work of time forward billions of years, yes, it's entirely possible that we might have another planetary collision.
You just don't have to worry about it for a long, long time.
a devastating collision made life on Earth possible.
that life threatens to destroy itself.
Our blue planet -- in a hostile universe, it sustains and nurtures life.
simple, single-celled organisms drift through the nutrient-rich oceans.
But their world is about to be destroyed.
When you talk about mass extinctions, you have at least two types -- one danger coming from outer space, another from our own very backyard on the planet Earth.
The Earth circles the Sun, but this orbit is unstable.
Over hundreds of thousands of years, it changes, swinging the planet further out into space and pivoting on its axis.
Tilted away from the Sun, the Earth cools.
something turns this natural cooling into a global catastrophe.
It is one of the most dangerous things in all the universe life.
Tiny organisms populate the oceans.
There's no oxygen around and that's the way most of them like it.
But then a new kind of bacteria evolves -- cyanobacteria.
And these guys create a serious gas problem.
Imagine Earth billions of years ago.
There's no oxygen.
Everybody's happy.
Then cyanobacteria start making oxygen.
It's a toxic pollutant.
If there was a regulatory agency at the time, they would've been outlawed.
Eventually they polluted the whole world.
They had really precipitated an ecological crisis of global proportions.
The great oxygen crisis upsets the greenhouse effect that keeps the planet warm.
Global temperatures plummet.
The ultimate culprit is biology.
Biology makes a mess of the planet, produces oxygen.
The oxygen destroys the greenhouse effect of methane and that freezes up the Earth.
ice creeps out from the poles.
Instead of warming the planet, sunlight bounces off the ice, temperatures fall, creating more ice which bounces more sunlight back into space, and so on and so on until the cooling becomes unstoppable.
The ice marches on.
Temperatures plunge.
The blue planet turns white.
It's a snowball Earth.
And incredibly, this may've happened not once but at least three times over the following billion years as the planet lurched around the Sun.
But throughout all of this and against all the odds, a handful of species clung to life, thanks to volcanoes.
Even in an Earth that was covered almost entirely by ice, volcanoes would've been punching through that.
So you certainly have pockets of water lying about.
And life was able to carry on and get through these cold periods.
And the whole time, the volcanoes that help sustain life have been pumping out carbon dioxide.
As this greenhouse gas increases, the atmosphere warms.
Until 640 million years ago, the last, great snowball Earth ends.
And the survivors emerge into a new world.
After snowball Earth goes away, things get very interesting.
A lot of opportunities open up for life, water's flowing, ice is melting, organic material built up that hasn't been decomposing.
So you can imagine that there will be a burst of development.
In the meantime, cyanobacteria have been churning out ever more oxygen.
Other organisms will either learn to breathe it or die.
Many organisms decided that this poison could be useful, it's energetic, and that allowed them to have an energy source that was so powerful that they could build huge, complex structures -- poof, animals.
Snowball Earth is an environmental disaster and an evolutionary triumph.
Complex life flourishes.
But most of these creatures will never evolve beyond this point.
Something stops them dead.
It is the most powerful weapon in the universe, and it strikes in the blink of an eye.
In a violent universe, against all the odds, life survives.
But consider this -- at any moment, the universe could pull the trigger on a secret, deep-space death ray, obliterating all life on Earth.
And until the 1960s, nobody even knew it existed.
- the height of the cold war.
The United States and Soviet union raced to outgun each other, stockpiling and testing nuclear weapons.
America was worried that the Soviet union would be able to test nuclear weapons in space.
So what America did is launch the series of satellites to go out into space and look for the tell-tale flash of gamma rays from nuclear tests.
On July 2, 1967, the satellites detect a burst of gamma rays, the most energetic and destructive form of electromagnetic radiation.
Immediately there was panic in the Pentagon.
Perhaps the Russians are testing super-gigantic hydrogen bombs in outer space.
And we're just caught flat-footed.
But it's not bombs.
It's something far deadlier.
And then the realization sunk in.
"Oh, my god.
"These flashes are coming from outside the milky way galaxy.
They must be billions of light-years away.
" A new source of energy, second only to the big bang itself had been discovered.
When gamma ray at first were first discovered, people assumed that they must be fairly close by.
"Of course they have to be close by.
They're the brightest thing that we see in the sky.
" And now we know that gamma ray burst, not only are they not nearby, they're not in our galaxy, they're not in nearby galaxies, but they're close to the edge of the universe.
They're as far away as anything else that we observe, and that's completely ridiculous.
Over distance, light gets dimmer.
The further light has to travel, the dimmer the light should be.
If light from a distant galaxy comes to Earth and it has gamma-ray energies, then that explosion must've been incredibly powerful, because it turns out that as light travels through space, the wave length of the light gets stretched out.
And this stretching caused the light to lose energy.
And since the light rays have traveled a very great distance through the cosmos to reach us, and they're still gamma rays, they must've started out with a great deal of energy.
And the amount of energies are unbelievable.
You're talking about the entire energy budget of the Sun over its whole lifetime emitted over the course of just a few seconds.
These are amazingly violent, amazingly powerful events.
In June 2008.
NASA launches the Fermi space telescope.
Its mission -- discover the source of these huge blasts.
What Fermi does is open our eyes to the universe that's there but gives us such a different view that we really get a deeper and greater understanding of what's going on.
If you had gamma-ray eyes, the milky way would be blazingly bright across the center of the sky.
Your vision would be dominated by these very dense, pulsing stars and super-massive black holes.
And it's black holes that may solve the mystery of gamma-ray bursts.
When a truly gigantic star dies, one at least 25 times more massive than our own sun, it collapses to form a black hole.
Scientists believe black holes are one of the few things in the universe large enough and powerful enough to generate gamma-ray bursts.
Gamma-ray bursts are the birth cries of black holes.
When a massive star explodes and becomes a supernova, the core collapses and forms a black hole.
Material falls around it, swirls into a huge disk, it gets incredibly hot.
As it's falling into the black hole it forms a tremendous magnetic field, as well.
The remains of the star spiral towards the black hole.
Enormous electromagnetic forces fling some of this matter outwards.
Hurtling up and down the black hole's huge magnetic fields, the matter collides with debris from the initial explosion, accelerating to close to the speed of light, heating to millions of degrees.
These high-speed collisions unleash unimaginable amounts of energy.
This is the gamma-ray burst.
Gamma-ray bursts are fascinating.
You can study them throughout the universe because they're so bright.
But if you move them in really close to the Earth, let's say within they become extremely destructive.
The beams are so huge that if a gamma-ray burst occurs, say, by the time it reaches the Earth, the beam will be wide enough to engulf our entire solar system.
Basically, if you were standing on the Earth and you looked up, you would see a flash of light, and before you could even say, "what's that?" You'd be gone.
The amount of energy in the beam that travels across space is so intense it would basically light the Earth on fire from that distance.
It would strip off the Earth's atmosphere, it would boil the oceans, it would melt the rock.
It would be apocalyptic beyond apocalyptic.
This is the worst-case scenario.
But what if a gamma-ray burst hit the Earth from further out? Would we survive? People ask what would happen if there was a gamma-ray burst within 6,000 light-years of the Earth.
It's actually not the right question.
There have been gamma-ray bursts that close to the Earth, and there probably have been extinctions of life on Earth due to gamma-ray bursts.
after snowball Earth, the oceans are teeming with complex life.
But 440 million years ago, And the killer may have been a single devastating gamma-ray burst.
The blast penetrates the oceans' upper layers, killing the creatures that live near the surface.
Creatures living further down survive the initial onslaught, but not for long Because the blast also damages the Earth's ozone layer, exposing the planet to the Sun's deadly uv radiation, triggering acid rain and lowering global temperatures.
Over half a million years, the creatures that survived the gamma-ray burst get taken out by its after effects.
If a gamma-ray burst has wiped out life in the past, it could happen in the future.
And astronomers think the next burst could come from a dangerously unstable star, wr 104.
Wr 104 is the nightmare.
We now have a potential candidate for what may become a gamma-ray burster with our name on it.
We are literally staring down the gun barrel of wr 104.
It's not one but two massive stars orbiting each other.
The stars will die in a massive explosion, spawning a black hole, and blasting out gamma rays.
The object is about 8,000 light-years away, so we are within the kill radius of this object.
So you could be doing your laundry tomorrow, look up in the sky, and all of a sudden, there's this burst of radiation raining down from the heavens.
The radiation rips off the Earth's ozone layer, creating a toxic smog and exposing us to the Sun's deadly rays.
Life as we know it could cease to exist.
Plants would be scorched, animals, which depend upon plant life, will then begin to die.
Human civilization would have to go underground.
It may sound like the death star destroying the Earth in "star wars," but the difference is the death star isn't gonna happen, a gamma-ray burst might.
Our extinction could happen at any time.
And the fatal blow doesn't have to come from space.
It could come from the very thing that makes life possible - - the Earth itself.
Our planet conceals a weapon of mass extinction, primed to detonate at any moment, hidden deep beneath our feet.
Unleashed, the heat inside our planet could wipe out everything in its path on a massive scale.
after a gamma-ray burst may have devastated life in the oceans, the survivors have colonized the land.
Among them, a motley crew of monster reptiles - - scutosaurus and gorgonopsians.
They're successful, strong, and doomed.
Around about the biggest mass extinction that the Earth has ever seen, the end-permian extinction.
Just over 90% of marine fauna and around about 70% of land fauna disappeared from the planet.
The killer is a volcanic eruption -- the biggest and most catastrophic the world has ever seen.
in what is now Siberia, the Earth's crust ruptures, pushed beyond breaking point by a vast plume of hot magma surging up from deep inside the planet.
The Earth itself can internally generate some very devastating events, millions-of-years-long events in the form of major volcanic eruptions at the continent-scale level.
These are basaltic-volcanism events that flood entire portions of the planet with basalt lava.
Lava spews for two million years.
There's enough lava to cover the entire United States beneath a thousand feet.
And the death toll extends around the Earth and deep into the oceans.
The question is why.
The answer lies with the most volcanic country on Earth -- Iceland - with a similar, smaller eruption just 230 years ago.
June 1783.
A terrible chain of events unfold that will devastate Iceland and kill up to a million people around the world.
Near the village of laki, a 17-mile-long tear opens up in the Earth's crust.
These holes and cracks in the ground that you can see, they would've had jets of magma, jets of lava flying up into the sky.
To give you an idea of scale, the overall the amount of material that came out of laki is about 3 1/2 cubic miles of volcanic material, and that's a lot material.
And it's not just the size of laki that makes it so special, it's actually what's inside this and what came out of this that's the dangerous thing.
Because it had lots of sulfur gases associated with the eruption and also lots of fluorine, quite poisonous gases.
Sulfur dioxide spreads out around the atmosphere.
Its droplets form a giant mirror reflecting the Sun's warmth away from the Earth.
It's clear that even a relatively small eruption like laki can cause big, dramatic effects in terms of the climate.
In the northern U.
S.
, there was one of the coldest winters ever recorded.
In fact, the Mississippi is recorded to have frozen.
It's been implicated in causing the big famine in Japan.
So, the effects, potentially, for volcanoes that spew these horrible gases into the atmosphere can be catastrophic on a global scale.
Now picture the siberian eruptions They're 200,000 times larger than laki and last a million times longer.
They release massive quantities of gas triggering extreme climate change -- first cooling, then heating the atmosphere.
land-based creatures die, including the mighty gorgonopsians and scutosaurus.
But worse is to come.
As the oceans warm, they lose oxygen and stagnate.
Toxic algae takes over, poisoning the oceans with hydrogen sulfide, killing 96% of marine life, and leaving purple sulfur bacteria to overrun the oceans, turning the water pink.
This is the closest the Earth has ever come to total extinction.
But over 200 million years, the survivors adapt and evolve.
A new group of animals emerge.
They are the largest, most successful creatures the Earth has ever seen - - the dinosaurs.
But they, too, will face annihilation.
Cosmic killers prowl the universe threatening to wipe out life on Earth.
They've struck before, pushing life to the edge of extinction.
They will strike again, and it could happen before you've finished watching this show.
February 15, 2013.
It's another cold winter's day in the siberian city of chelyabinsk when literally, out of the blue A 14,000-ton, 65-foot meteor tears through the atmosphere at 42,000 miles an hour.
It explodes in the air unleashing a powerful blast wave, shattering windows, damaging 7,000 buildings, and injuring 1,500 people.
Now imagine what would've happened if the asteroid had hit the Earth in one piece.
And we saw what happened over Russia, over in chelyabinsk, with an object that could have hit the Earth -- could've hit the Earth with a force of perhaps 20 Hiroshima bombs.
If you watch those videos of that meteor in Russia with the incredible Sonic boom, you could see how even a small object -- relatively small in a cosmic sense -- could produce a dramatic event for humans.
The way it works is small objects are hitting the Earth every day, large objects, every week, larger objects still, every year.
And an object the size of the chelyabinsk meteor strikes, on average, once every century.
So when the next big one strikes -- not if what will happen? The clues lie in the past in the extinction of the dinosaurs.
About 65 million years ago, there was a perfect morning on Earth.
I would've loved to have been there to see the giant dinosaurs, you know, the pterodactyls flying through the air, all of that.
And then something changed, and the Earth would never be the same.
If you would've looked into the sky, you would've seen a relatively dim light at first coming towards you, getting brighter and brighter, and hotter and hotter.
It's a six-mile-wide rock the size of mount Everest racing towards the Earth at 25,000 miles an hour.
The first wave of destruction would've started before this object even hit.
There would've been shock waves, heat, and winds going across the entire planet.
Everywhere that was under the path of this asteroid would've been seared, set on fire.
The oceans would've been boiling underneath it.
The asteroid smashes into the ocean off of what is now Mexico's Yucatan peninsula.
It strikes with a force two million times greater than the biggest nuclear bomb ever detonated, and blasts out a crater A super-heated shock wave roars out at twice the speed of sound.
soar to the edge of space.
Two hours after impact, a 300-foot Tsunami smashes into the coast of what is now the U.
S.
A.
Reaching as far as North Carolina.
Over the next few hours and days, the debris rains down, setting the planet ablaze.
In the following weeks and months, smoke from the fires adds to the dust blasted into the atmosphere.
There was so much pulverized rock, all of the burning materials up into the atmosphere, you wouldn't have been able to see the surface.
And on the surface, you wouldn't have been able to see the Sun, and it was like that for a long time.
This ancient apocalypse is a disaster for the dinosaurs but without it, we wouldn't be here.
Back then, during the time of the dinosaurs, our ancestors were probably little, furry mammals that were an evening snack for a dinosaur.
When the dinosaurs got wiped out, these small, little, furry mammals began to expand in size to take over the niche left over by the dinosaurs.
So, one life-form replaces another life-form, in this continual process called survival of the fittest.
We are here because our ancestors survived the extinction event, and, in fact, flourished because of it.
From our point of view, that extinction event was a good thing, but we're here for a brief moment.
And there will be disasters in the future, and one of them will destroy us.
There is a 1 in 5,000 chance that an asteroid, the same size as the dinosaur killer, will strike within the next 100 years, and it could happen at any time.
It is a real possibility that it could happen in the next 10 minutes, but is a tiny possibility.
So, I always say, "you don't need to prepare very much "for winning the lottery, you know.
"You may have a similar chance to getting taken out by an asteroid in the next 15 minutes.
" April 2014.
Scientists make a shocking announcement -- since the year 2000, in the Earth's atmosphere, each one with the force of a nuclear blast, with some up to 40 times more powerful than the Hiroshima bomb.
And we didn't spot a single one of them before they struck.
Even if we had the technology to detect an asteroid before it hit us, could we destroy it in time? The Hollywood favorite, of course, is to go out there and nuke it, blow it to smithereens, right? That could actually work in the case of some particular, you know, last-ditch effort for asteroids of just the right size.
But a nuclear bomb could just make a bad situation worse.
Transforming an asteroid into large radioactive chunks that rain down all over the planet.
But there are also techniques, like shining a laser on the asteroid or sunlight, which would create an artificial cometary jet, if you will, would vaporize some of the water and the minerals on the surface of that asteroid to gently push it off to the side.
Another fantastic technique, a very robust one, is something we call the gravity tractor.
You just park a spacecraft, the mass of a communication satellite, next to that small asteroid and use the thrusters on the spacecraft to keep it hovering just off the surface of the asteroid, and that uses then gravity between the two as a tow line to move the asteroid ever so gently off course.
Right now these technologies are still on the drawing board.
If they do become a reality, we'd still need months or years to prepare.
Rogue planets, ice ages, gamma-ray bursts, volcanic eruptions, and asteroid strikes.
We've survived the worst the universe can throw at us, but our species will still face extinction.
It's as inevitable as the Sun rising.
In a cosmic battle to the death, we are the survivors, but eventually the universe will win and we will face extinction Threatened by the very thing that gives us life -- our creator, the Sun.
We orbit a giant nuclear bomb, the Sun, but, you know, it's not going to explode.
It's too small to explode, but what happens with the Sun is that every day, it's a little bigger than it was the day before.
Since the Sun's birth, hydrogen has been fusing into helium in the Sun's core.
As the helium accumulates, the core gets denser.
With 150 million tons of helium squeezing into the core every second, the gas compresses and heats up.
Right now the temperature inside the Sun's core is 27 million degrees, and its getting hotter all the time.
What happens when you heat up a gas? It expands, and so that's what the Sun is going to do.
As the Sun swells, it will appear brighter.
In 2 billion years, the Sun will be about 15% brighter and that will lead if the Earth remains in its present orbit inevitably to a runaway greenhouse effect.
The oceans will evaporate, and the surface temperature of the Earth could easily be a 1,000 degrees.
So, if we don't do anything, in 2 billion years, we'll be toast.
If we're still here on Earth, we'll perish.
Other tougher species may find a way to adapt and survive, but they'll be living on borrowed time.
It's gonna fill up the sky.
From horizon to horizon, the sky will literally be on fire.
the Sun runs out of hydrogen and enters the final apocalyptic stage of its life, bloating to 100 times its current size.
Our life-giving sun is now an angry, red giant.
The red giant stars are so big they will actually eat up their own planets.
We know of the examples of red giants that go all the way out to where the orbit of Jupiter is in our solar system.
The sun will not get quite that big, but it'll probably get about out to Mars.
And eventually, in fact, the Sun will be so large that the Earth will be located inside of the Sun, which certainly won't be a very pleasant place to be.
The red giant's bloated body absorbs the Earth, incinerating our planet until its nothing more than gas and dust inside a dying star.
The death of the Sun is the ultimate mass-extinction event.
There's 100% chance it will happen.
A 100% chance it will destroy our planet and any life left on it.
But life on Earth may not be the only life in the solar system.
As the Sun brightens, you can imagine a wave of habitability going out.
So right now it's on Earth, it'll go to Mars, and it'll go to Jupiter, and its moons.
Scientists think Jupiter's moon europa may already harbor alien life in a deep, liquid ocean beneath its frozen crust.
But out at Jupiter, it'll be much warmer but not so warm that it would destroy everything.
So even when the Earth is gone, if there's life on europa, it may be able to endure that.
But will our species go on? Can we survive the loss of our home planet? The universe is like an ecosystem -- living things are gonna survive based on the law of survival of the fittest.
What decides if you're fit in this universe is if you're able to leave your planet and go out and populate other planets.
So the only species that are gonna live on forever are the ones that leave their planet.
We can't control the universe, but we may be able to control our fate.
Inevitably, in the long term, the Earth is gonna become uninhabitable.
It's just the way the universe works.
It wasn't made for us, it doesn't care that we exist, and it won't care when we go away.
The only people who care about that are us, and we might be able to do something about it.
In that sense, we have a fighting chance.
Our intelligence is our greatest asset.
It's the end result of four billion years of extinction and evolution.
And it may give us a chance to do something that no other species has ever done before -- break the cycle of creation and destruction and live on.
Everything that you and I are is a consequence of the way the universe works.
The universe is violent, the universe is dynamic, it's constantly pushing us to change.
And here we are, these incredibly evolved, interesting creatures.
We're a direct consequence of the violence, which, in turn, was our creation.