Asteroids... Colossal lumps of rock and metal
flying through our solar system at 40,000 miles per hour.
They could destroy the human race...
Asteroids are civilization-killers.
Or transform the future
of human space exploration.
Asteroids are a real opportunity for humanity
as we begin to venture out away from planet Earth
into deeper space.
Where do these giants come from?
And are we prepared for the threat of Armageddon from above?
This is really a big deal. This is planetary defense.
To find out, we will strip these giants,
tear back their layers,
dive deep into their cores,
and reveal the secrets
hidden inside these devastating goliaths.
Captions by vitac... www.vitac.com
captions paid for by discovery communications
planet Earth...
The only known inhabitable place in our solar system.
More than 7 billion people live here.
Few realize that our home
is under constant attack from above.
Over 100 tons of dust and rock bombards the Earth
every day from space.
Most of it goes unnoticed.
But some space missiles are bigger.
From the size of an automobile to the size of a city,
they are asteroids, and they could be devastating.
We've seen it in the geological record.
An asteroid impact wiped out the dinosaurs 65 million years ago.
One asteroid... game over.
Understanding the enemy is a key part
of protecting our own species.
Understanding what's floating out there,
understanding what could come and hit the Earth...
That's part of the problem.
The other part of the problem is understanding
what their physical properties are.
Knowing about asteroids is, in my mind,
one of the most important responsibilities that we,
as a species, have not stepped up to yet.
Asteroids are mysterious, airless worlds.
Some are just a few yards across.
These loose clusters of boulders and dust
are leftovers from the birth of the solar system.
Other asteroids are thousands of times larger,
reaching hundreds of miles wide.
Beneath their surfaces, layers of rock and minerals
wrap around dense metal cores like a planet.
These cosmic rocks hold the secrets
to the history of our solar system
and have the potential to end our civilization.
9:00 A.M., February 15, 2013.
Chelyabinsk, Russia, a city of over 1 million people,
all completely unaware of an incoming object
a few hundred miles above their heads.
An asteroid 60 feet wide hurtles toward Earth.
Its 10,000-ton body travels
at more than 50 times the speed of sound.
Entombed in a stone-and-iron structure,
glass-like veins streak through its body.
An asteroid this size could level a city.
9:20 A.M., the asteroid enters the Earth's atmosphere
and begins to burn up.
Suddenly, there was this brilliant light in the sky,
brighter than the sun.
People couldn't look at it, it was so bright.
It was moving at something like 20 kilometers per second,
12 miles per second, which is pretty fast.
You know, it's many times faster than a rifle bullet.
As the asteroid hits the atmosphere,
it compresses the air in front of it.
The pressure builds, and the temperature skyrockets.
It burns 30 times brighter than the sun.
Inside the fireball,
the asteroid is under extreme pressure.
Its glassy Jade veins crack, weakening the entire structure.
18 miles above Earth,
the asteroid explodes,
releasing more energy than 30 atomic bombs.
You're detonating a huge bomb up in the atmosphere
that creates a huge shock wave, which then reaches the ground.
The massive shock wave rocks the city.
It is the second-largest meteor explosion
ever recorded on Earth.
It damages more than 7,000 buildings
and injures 1,500 people.
That shows you how bad an asteroid impact could be
and how vulnerable we are.
And I think that was a reminder
that we are a planet out in space.
You know, we think we're protected, but we really aren't.
In Arizona, astronomer Jess Johnson
works on predicting future impacts like Chelyabinsk.
We have groups of asteroids
that are uncomfortably close to our planet.
The more we know about how many of these objects
are in our neighborhood, the better off we are towards
mounting planetary defense and being able to
protect ourselves against possible impacts.
The Catalina sky survey telescope
sits on mount Lemmon, 9,200 feet above sea level.
This one right here is our 60-inch refractor,
and the primary purpose of this telescope
is to actually look for asteroids.
As the sun sets, Jess's work begins.
Jess trains his telescope on a small section of the sky.
The telescope relays the images straight to a computer
programmed to spot anything that might be an asteroid.
This is what a raw image from the telescope looks like.
You can see here that the computer system
has actually marked out
something moving in an otherwise stagnant star field.
And if we are fairly sure that this is going to be an impactor,
all the bells and whistles go off.
This is really a big deal. This is planetary defense.
Defending the planet is a lonely job,
but it's worth the sacrifice.
You end up living a rather solitary,
monkish kind of existence on the top of a mountain,
but you can always claim that, in some small way,
you are contributing to the safety of the planet.
And that's pretty cool.
Over the past decade, Jess and the team
have discovered thousands of new asteroids.
They add the most dangerous to an international database
so that the teams around the world
can monitor asteroid trajectories.
Their work helps predict future impacts.
There will always be new asteroids to find.
Far beyond Mars, there's a vast expanse.
This is the asteroid belt.
It's over 100 million miles wide
and contains most of the asteroids in our solar system.
Here, millions of asteroids of all shapes and sizes
orbit the sun.
When they collide, they can hurtle fragments of rock
out of the belt and toward Earth.
Things will keep falling down on us,
so this is the universe we find ourselves in.
This is the reality.
There will be more asteroids coming in some day.
There are lots of rocks bigger than Chelyabinsk...
In fact, billions of them out there... orbiting the sun.
And as long as they stay out there, I'm fine with that.
We can study them and go out there and look at them.
But, sometimes, they do, in fact,
get their orbits altered,
and that can drop them into the inner solar system.
And that's when they can start to pose a threat to the Earth.
The Chelyabinsk asteroid ended
in a powerful explosion,
but the damage could have been much worse.
What would it take for a single impact
to cause planet-wide destruction?
The Chelyabinsk asteroid strike
caused millions of dollars of damage
and reminds the world about the threat of asteroids.
But Chelyabinsk was just a small object.
Chelyabinsk was an incredibly dramatic event,
and, yet, the object that caused all that mayhem
was a fairly small object in the scope of asteroids
as a whole... only 20 meters.
The largest asteroid is 1,000 kilometers in diameter.
The largest asteroids could wipe out
most life on Earth.
It's happened before.
Over 65 million years ago, an asteroid taller than
mount Everest screams toward what will become
the small Mexican town of Chicxulub.
This 6-mile-wide Goliath smashes into the Gulf of Mexico
at approximately 40,000 miles per hour.
The impact releases more energy than a billion Hiroshima bombs.
It blasts a wall of fire and rock miles high.
At the epicenter of the strike, the heat from the impact
instantly vaporizes the water.
Beneath the surface, the rock melts,
leaving a molten layer 2 miles deep.
The enormous crater is around 112 miles wide
and about 20 miles deep,
more than twice the size of the big island of Hawaii.
Scientists belive this event wiped out the dinosaurs.
So, how can a single asteroid impact
lay waste to an entire planet?
A team at NASA's Ames laboratory in California hunts for clues.
Peter Schultz is the authority on asteroid impacts.
Asteroids have changed the Earth.
They've changed the life on the Earth.
The Chicxulub impact was not that rare an event,
so it's critically important to understand what happened then,
just to be able to understand what might happen in the future.
Peter uses a custom-built gun
to simulate asteroid impacts.
He will fire a small ball of aluminum at over
12,000 miles an hour directly into his model of the Earth
to re-create an asteroid strike.
You're clear right now.
Okay. Lock and load.
High voltage is good.
Ooh!
Gorgeous!
There's this big, giant plume that goes straight up.
And this plume is heading straight out into outer space.
This kind of impact shoots dust and vapor
straight up, leaving a relatively small,
circular zone of debris.
For a vertical impact, a lot of the energy occurs locally,
sending it up and out, and that disappears.
Most of that got checked in the land right in that region.
But some dinosaurs lived thousands of miles away,
on the other side of the planet.
How could this impact affect them?
I don't think this is what happened in Chicxulub.
So, what did?
Peter believes the impact site holds vital clues.
Hidden beneath the Gulf of Mexico today
lies the Chicxulub crater.
Most small craters are circular.
But the Chicxulub crater is giant,
and its inner rim is shaped like an egg.
Under its skin, there is a layer of lighter-colored debris
and shattered rock.
This is the fallout from the impact.
It is far deeper on one side of the crater,
suggesting the asteroid struck the Earth at an unusual way.
Peter believes this is evidence
that the asteroid hit not head on,
but at a shallow angle to the Earth.
We wanted to see what happens when we come in at a low angle.
We're gonna be coming out of here.
Rolling.
The low-angle impact
produces a different kind of crater.
It's egg-shaped, just like the crater in Chicxulub.
That's much more serious than a vertical impact.
For life on Earth, it would have meant
that there was a zone of death and destruction.
The Chicxulub asteroid approaches at 90 times
the speed of a jetliner...
and crashes into the Earth at a shallow angle.
It unleashes its huge energy and hurls billions of tons
of vaporized rock into the atmosphere.
A cloud of superheated dust and gas covers the globe.
Particles of soot block the sun
and plunge the world into darkness for a year.
70% of all species on Earth perish.
We don't know how many times Earth has been hit.
Today, there's little sign of our planet's turbulent past.
You can't see the crater from every asteroid
that's ever hit the Earth.
The reason why is because the Earth
has active geology and weathering.
So most craters have been wiped away.
Volcanic eruptions, Earthquakes,
and flowing water have erased most of the evidence.
But a record of past impactors does exist
on our nearest neighbor, the moon.
The moon has no atmosphere,
has no running water, has no weather,
and so it has preserved a record
of everything that's hit it over the age of the solar system.
Looking at the moon tells us how many asteroids
must have hit the Earth in the past.
NASA's lunar orbiters have photographed
over 98% of its surface in high resolution.
The images reveal an extraordinary story.
The moon has over 8,000 impact craters.
One of the most unusual ones
lies south of the moon's equator.
It's a 4,000-foot-deep hole known as the messier crater.
In the moon's distant past,
an asteroid slammed into the moon's surface
at a very low angle and created a 7-mile-long hole.
Colossal fragments of rock exploded upwards
and left a second crater right next door.
Two bright streaks of debris over 60 miles long
still scar the lunar landscape today.
A reminder of the dangers that threaten our own planet.
Asteroids are civilization-killers.
So knowing about asteroids is, in my mind,
one of the most important responsibilities that we,
as a species, have not stepped up to yet.
But there's a limit to what we can learn
about asteroids from here on Earth.
To find out more, we must send a spacecraft
190,000 miles into the unknown.
The Chicxulub impact proves a single asteroid strike
could wipe out an entire species.
To protect ourselves, we need to know more about the threat.
And as we discover more about asteroids,
we could also unlock the secrets of our universe.
Asteroids are remnants from the earliest stages
of the evolution of the solar system.
Studying them tells us about our own world,
the processes that gave rise to Earth.
If you go to an asteroid,
you can actually pluck out a piece of the solar system
very close to its birth.
So one of the fascinating explorations
is to form a mission to go to an asteroid.
Here in Denver, Colorado,
a team of scientists prepares to launch an unmanned probe
to study an asteroid in more detail than ever before.
Tim Linn is the project's chief systems engineer.
So, we've done a lot of ground-based measurements
of asteroids and other bodies throughout our solar system,
but what we've never been able to do
is actually go grab a sample, bring it back to Earth,
and then discover where we really came from
as a solar system.
These samples could contain pristine minerals
from billions of years ago.
The minerals could help scientists understand
the conditions that went into the making of our solar system.
The spacecraft's mission is to pull up alongside
a spinning asteroid,
use its articulated arm to touch the surface,
collect a sample, and stow it in a removable capsule,
which will travel back to Earth.
First task... Choose the right asteroid.
We actually have 500,000 asteroids
in our main asteroid belt,
and of those, there's a small number of them
that actually made it close to Earth,
which we call near-Earth asteroids.
And those are the ones that we really were interested in.
The team needs a rock that is close enough,
big enough, and slow enough for their lander to make contact.
The probe's target is an asteroid 1,600 feet wide.
It's called Bennu.
Bennu's orbit will bring it within 190,000 miles of Earth,
closer than the moon.
It's not just one lump of rock.
Beneath its loose, dusty shell is a cluster
of boulders and rubble...
held in place by a gravitational field
10 million times weaker than Earth's.
Bennu's carbon-rich rocks are perfectly preserved.
And now, for the first time,
scientists will be able to take a closer look.
On its mission, the space probe captures high-resolution images
of Bennu's surface.
A team here at the university of Arizona
is designing the on board cameras.
Bashar Rizk knows that space
will push the cameras to their limits.
We're going to a place
that humanity has never been before.
We think we know what we're going to expect,
but we don't really know.
The team was under huge pressure to have
their equipment ready for the mission's 2016 launch.
The planets wait for nobody.
These deadlines that we're working to are hard deadlines.
Okay, it's very rare that you're going to be able to wait a year
and then be able to pick up where you left off
and go on the mission that you thought you'd be going on.
The spacecraft has three cameras on board
to photograph the surface of the asteroid and search
for a suitable landing site.
Okay, let's take some data.
We go to new places hoping we'll learn something
so compelling that it will force us to re-examine
the way we think about any number of fields.
The team hopes that their images of Bennu
will tell us more about the history of our own planet.
4.6 billion years ago, as the sun begins to form,
the early solar system swarms with gas and dust.
Inside this giant spinning disk,
particles of dust fuse to become rocks and boulders.
As they collide,
they stick together, and the boulders get bigger.
Over millions of years, the collisions in this
dust cloud will form the planets.
The rocks left over become the asteroids like Bennu.
This mission isn't just about photographing Bennu.
The team also plans to bring a piece of it back to Earth.
In Denver, a second team tests the probe's mechanical arm.
This arm is really the heart of the mission.
It's the one that's actually gonna go grab the sample,
capture the sample inside the mechanism,
stow the sample into our sample-return capsule,
and then bring that back.
- All right. - The team plans to analyze
over 2 ounces of asteroid dust
to learn more about the chemical conditions
of the very early solar system.
Tim hopes this could explain how planets form
and even how life began.
This will be the biggest sample of this kind of asteroid
that we've ever been able to get,
and so I know we'll be rewriting the textbooks.
You're really bringing back billion-year-old information
that is gonna truly change what we know about our solar system
and about the history of our solar system.
But Bennu's easy-to-reach location
also makes it one of the biggest threats to Earth.
It's big enough that it would cause a considerable amount
of damage of it hits the Earth.
And it comes around often enough
that the chances of a collision are not small.
You know, as these things go, they're pretty large.
NASA keeps a hit list of almost 1,500 asteroids
that threaten Earth.
Each asteroid is over 300 feet wide
and ranked according to its size, speed,
and chance of hitting the Earth.
Bennu's close orbit makes it number 2
on the list of the most dangerous.
None of these asteroids pose an imminent threat to Earth,
but any one of them could cause the most destructive event
in human history.
Someday, we're gonna look up into the sky
and have measurements that will prove
that a large asteroid will hit the Earth.
And then the question is, what are we gonna do about it?
What pushes asteroids out of their orbit
and on to a collision course with Earth?
And is there anything we can do to stop them?
Thanks to groundbreaking missions,
asteroids are beginning to reveal their secrets.
But to protect ourselves from an impact,
we need to understand what sends some of them
spinning into a collision course with the Earth.
At the heart of our solar system is the sun.
Its massive gravity holds the planets
and the asteroids in orbit.
But the sun isn't the only object
creating huge gravitational forces.
At almost 90,000 miles in diameter,
Jupiter is the biggest planet in our solar system.
Beneath its violent atmosphere,
is an ocean of hydrogen.
The pressure is so high that the gas behaves
like a soup of liquid metal.
Deep inside, at the heart of the planet,
appears to be a partially dissolved core
of rock, metal, and ice.
Jupiter's huge mass creates a giant gravitational force
that pulls on everything,
especially the asteroids traveling close to it.
When it comes to the real movers and shakers in our solar system,
you've got the sun and you've got Jupiter.
Those really are the major bodies.
And when Jupiter formed,
it sort of limited the formation of other planets.
The asteroid belt is an area where Jupiter pulled apart,
gravitationally, any planet that tried to form there.
So the asteroid belt is where it is
because of the effect of Jupiter's gravity.
Jupiter now holds its army of asteroids
in orbit around the sun.
But any small disturbance can send an asteroid
hurtling out of the belt
and potentially on to a collision course with Earth.
Just one stray space rock
could destroy life on our planet.
To protect ourselves, we need to find a way
to deflect incoming objects.
Orbits of the asteroids are absolutely gigantic
all the way around the sun, hundreds of millions of miles.
So if you can change the angle they're moving at,
just by a little, tiny hair, over millions of miles,
that will change the course of the asteroid
and miss us entirely.
A team in Scotland thinks they have a solution.
Massimiliano Vasile believes that the heat of this
laser light is enough to move an asteroid in space.
The team places a rock sample that was once part of
an asteroid into a vacuum chamber to simulate space.
Let's go.
The laser heats a small spot up to 5,000 degrees Fahrenheit,
causing vaporized material to shoot from the rock.
In space, the thrust from this blast would push the asteroid.
The exact amount of laser power they will need
depends on what type of asteroid they're trying to deflect.
Not all asteroids are chunks of rock.
Some of the biggest asteroids in our solar system
are more like planets.
These goliaths are hundreds of miles wide.
Beneath their rocky crust is a layer rich in minerals...
that wraps around a metallic core.
The metal makes these objects far heavier than
a rocky asteroid of the same size and much harder to deflect.
Massimiliano needs many more laser-carrying spacecraft
in his swarm to deflect an asteroid the size of a planet.
But he believes that, one day,
this might be Earth's best option.
Asteroids will continue to escape Jupiter's gravity
and hurtle towards Earth for millennia to come.
But, luckily, most keep a stable orbit
millions of miles away from our planet.
And rather than destroying us, some of these objects
contain valuable resources on a colossal scale.
Asteroids are full of resources that humans can use.
There are asteroids that are abundant in water.
There are asteroids that are abundant in rare metals.
The resources in these asteroids
could be the key to survival beyond planet Earth,
allowing humans to travel deeper into space than ever before.
Asteroids are chunks of rocky debris
that orbit our solar system.
They have the power to end civilization on Earth.
But the more we learn about these space rocks,
the more surprising they become.
This is Ceres.
It measures 590 miles across, roughly the size of Texas.
Ceres is the largest object in the asteroid belt.
But it may have more in common with Earth
than its rocky neighbors.
Beneath its thin, dusty crust, scientists believe a thick layer
of ice and water reaches deep into the asteroid.
This discovery could be the key to deep-space exploration.
If we're going to expand human activity
beyond low Earth orbit in a meaningful way,
we can only do that if we can find the resources out there
and learn to live off the land.
Asteroids are a real opportunity for humanity
as we begin to venture out away from planet Earth
into deeper space.
For example, there are asteroids that are abundant in water.
That water can be used for humans to drink,
and it could also be used to fuel rockets.
With the potential to lift off in a few years,
NASA's space launch system
is designed to propel humans into deep space.
It would be the largest, most powerful rocket ever built.
At the Michoud assembly facility in New Orleans,
engineers assemble the body of the spacecraft.
Great civilizations have always had explorers,
and it's gonna take a big rocket to go do big things.
Patrick Whipps leads a team
on this multi-billion-dollar project.
Across this 43-acre facility,
teams construct the spacecraft's components.
Getting off the ground is the most difficult challenge
for space flight.
The rocket is powered by liquid hydrogen
and liquid oxygen.
It will burn through most of its fuel
within 8 1/2 minutes of launch.
To travel beyond Earth's orbit, we will need to refuel.
The ability to take water and split it into
its constituent hydrogen and oxygen is something
we've known for a long time.
If we can find sources of water in the asteroids,
we potentially can produce enough liquid hydrogen
and oxygen to become a rocket fuel in faraway places
so that we wouldn't have to try to, as it were,
bring all of our lunch with us every place we go.
In the future, could an asteroid like Ceres
provide a gas station for a manned spacecraft?
A discovery made in January 2014 provides new clues.
Erupting from Ceres' dusty surface,
plumes of water vapor explode into space.
These plumes suggest there are vast reserves
of water deep below.
Scientists now believe as much as 25% of this asteroid
could be water.
That's more freshwater than exists on planet Earth,
enough to refuel NASA's new rocket nearly 3 billion times.
There could be millions of asteroids
with water like Ceres all over the solar system.
Asteroids are like gas stations.
It's where we go to get the fuel to go where we want to go.
Some of these asteroids could even allow us
to refuel on much longer journeys.
On the edge of the solar system, over 3 billion miles from Earth,
lies the Kuiper belt.
This chilly expanse almost 200 times bigger
than the asteroid belt is home to dozens of massive,
icy objects similar to Ceres.
Numbering in the hundreds of thousands, icy bodies,
including comets, also inhabit this alien world.
Some are over 60 miles wide.
Could these cosmic ice balls create a chain of gas stations
and one day enable humans to travel out of our solar system?
Asteroids were once seen as just space junk.
Today, we're learning much more about them
as a threat to life on Earth,
but also their great potential as platforms into deep space.
Asteroids are a big opportunity for humanity,
because, ultimately, we're gonna have to leave the planet,
and we're gonna probably do it one step at a time.
And that's going to include landing on asteroids,
mining asteroids,
and using them as stepping-stones to the cosmos.
The realization that near-Earth asteroids contain resources
that we could use to expand human activity
beyond low Earth orbit is a game changer.
The only way to fully investigate asteroids
is for humanity to visit one.
And that was exactly NASA's plan.
Johnson space center, Houston.
Here, astronauts have been training for their most
ambitious mission to date, a manned voyage to an asteroid,
initially proposed to launch in the 2020s.
The Neutral Buoyancy Lab
is the largest indoor pool in the country.
It provides a unique opportunity for astronauts
to experience near-weightlessness
as NASA develops the space suits and equipment
they need for the mission.
Astronaut Rex Walheim was preparing the team
for what to expect when they got there.
They would be the first humans to land on
and study an asteroid in space.
This is a neutral buoyancy lab mock-up of the equipment
we'd have when we do an asteroid-retrieval mission.
We're gonna be developing the tools and the suits
and all the equipment we need to do
the actual human part of the asteroid mission.
So, a crew of up to four would rendezvous with the asteroid,
and they'll latch on to it, and they'll do
a couple of spacewalks to go out and sample the asteroids.
The first challenge for the astronauts
would have been exiting the cramped capsule
and climbing out on to the asteroid.
What's important about these mock-ups is
dimensionally, they're perfect.
If there's a handrail on that mock-up down there,
there's a handrail in space.
And so you can develop what's called kind of a muscle memory,
like when you play the piano
and you don't think about what you're doing.
Next, collect samples from the surface of the asteroid
and make it back safely into the spacecraft.
This facility will be a huge part
of any asteroid-retrieval mission,
because we're gonna really have to practice our spacewalks
and get them down so we absolutely know
exactly what we're gonna be doing.
It's gonna be a challenge, 'cause we're gonna be
going farther than we've gone in 40 years.
Projects like this could one day
be the first step to colonizing space.
There are still millions of asteroids to discover.
In the future, could these giant lumps of rock one day
provide a home for humans and a platform for us
to travel through deep space?
One asteroid could provide a human colony
with building materials, water, and precious metals.
When you look at the history of humanity,
the history of science, ideas that were crazy
at first become commonplace over time.
We have airplanes in our sky. We fly to the moon.
We send space probes to other planets.
Pushing these boundaries is how we discover these things.
As we continue to study asteroids, there's no limit
to what we'll be learning about our early solar system,
about the state of our solar system today,
about the hazards that they represent,
about the opportunities that they offer for our future.
Asteroids, the mysterious beasts
of our solar system,
are beginning to reveal their secrets.
Some of these cosmic rocks and boulders have the potential
to create hell on Earth.
Yet, hidden inside others,
scientists are discovering layers of mineral-rich
rock and ice that could expand our frontiers
by powering a trip into deep space.