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This show is fictitious.

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There is not actually
an asteroid

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headed to New York City today,

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but this is based on
simulations of such an event.

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We run simulations of
fictional asteroid strike

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to prepare for
the worst-case scenario.

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[Mike Rowe]
November 4, 2029.

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We face a countdown
to catastrophe.

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A giant asteroid hurtles
towards Earth.

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It's heading straight for

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the eastern seaboard of
the United States.

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The space rock could wipe out
an entire city

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and cause
widespread devastation.

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Can Earth survive?

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[electricity crackles]

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[electricity crackles]

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[explosion]

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New York City,
November 4, 2029.

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The deserted metropolis waited
for the asteroid to strike.

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A giant space rock entered
the atmosphere,

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heading straight for the eastern
seaboard of the USA.

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heading straight for the eastern
seaboard of the USA.

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[Plesko] As it comes through
the atmosphere,

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we would see something as
bright as the sun getting

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brighter and brighter
and brighter.

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[Durda] At speeds of maybe
20 kilometers per second or so.

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That's something like
18 times faster than

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the speed of a bullet
coming out of a rifle.

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This asteroid was
headed towards

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the most populous city
in America,

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and when it impacts,
it would deliver

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more energy than
1,000 Hiroshima nuclear bombs.

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more energy than
1,000 Hiroshima nuclear bombs.

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[ explosion ]

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It would level some of the most
expensive real estate

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in the world in seconds.

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There would be a crater where
Central Park used to be.

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There would be a crater where
Central Park used to be.

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I actually don't even like
thinking about this,

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[ stammering ]

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of how horrible it
would be.

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[Plait] This is beyond the
worst disaster

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the world has --
would have ever faced.

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There's nothing in our history
that would have

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done this much damage so
quickly and so devastatingly.

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[Rowe]
The story of the asteroid

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and the Earth's fight back

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started seven years ago,
here in Arizona.

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September 2022,

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the Catalina Sky Survey.

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Guardian of heavens
Greg Leonard drives

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to Mount Lemmon Observatory
near Tucson.

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He's on the hunt
for asteroids and comets.

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He's on the hunt
for asteroids and comets.

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[Leonard] We are the watchers of
the skies for the planet.

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We literally represent
the first line of defense

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against potentially
incoming asteroids,

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and I want to emphasize
the words planetary defense.

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This is not in the benefit
for one nation.

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This is for the entire planet.

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[Rowe] Greg takes
a series of images

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over a 20-minute period.

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Stars don't move
in the photos,

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Stars don't move
in the photos,

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but asteroids and comets do.

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A-ha.

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We can see
four points of light

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tracking across the background
of the stationary stars.

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This one is moving very
quickly across the sky.

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So this tells me

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this is a real
near-Earth asteroid candidate.

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[Rowe] It's one of over 27,000
near-Earth asteroids,

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[Rowe] It's one of over 27,000
near-Earth asteroids,

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or NEAs for short,
discovered by the early 2020s.

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The huge gravity of Jupiter
can rip space rocks

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from their home
in the asteroid belt.

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Some race outwards,
away from the sun.

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NEAs head inwards,
occasionally towards Earth.

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We didn't know it
back in September of 2022,

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but these were
our first images

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of a deadly incoming asteroid.

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[Leonard] It's relatively close
to Earth's neighborhood.

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We don't know exactly
how far it is yet,

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but it's close enough where
its motion across the sky

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appears rapid.

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[Rowe] The discovery
of an NEA set a series

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of planet protection protocols
in motion.

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Step one, enlist
a global team of experts

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to investigate
the asteroid's orbit.

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[Plesko] We have
some of the brightest minds,

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some of the best telescopes,

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some of
the biggest supercomputers

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working to protect Earth,

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collaborating
across language barriers,

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across international
borders to protect humanity.

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[Rowe] This international
planetary defense team

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was tasked with discovering
if the distant object

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was tasked with discovering
if the distant object

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would become
a serious threat to Earth.

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Their first job --

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determine if the NEA's orbit
would intersect with our own.

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[Plait] Orbits are
a little like roads, right?

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You've got a path
that something follows,

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and they can intersect,
you can have a crossroads.

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Now, typically, if only one
object is there,

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that's not a big deal,

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but if you have two objects
approaching that intersection

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at the same time,
they could collide,

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and that's the danger
from asteroids.

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and that's the danger
from asteroids.

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[Rowe]
The team of scientists

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track the asteroid
for four months.

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[Chodas] Over time,
you can build up observations.

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You can gradually narrow down
the possible number of orbits,

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then determine whether there's
any chance of a future impact,

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but if the asteroid
is orbiting the sun,

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the Earth is orbiting the sun,
and there's this dance going on.

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Sometimes the asteroid
is near the Earth,

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Sometimes the asteroid
is near the Earth,

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and we can observe it,
it's bright.

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Other times
the asteroid is

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on the other side of the sun.

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We can't observe it at all.

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[Rowe]
We were lucky.

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The asteroid was visible
throughout the fall of 2022.

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However, our observations of
the space rock's orbit

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showed a very real possibility

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that it would slam into Earth
in just seven years.

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[ whooshing ]

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Astronomers gave
the incoming asteroid

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a suitably appropriate name,
Apep.

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Apep was
the Egyptian god of chaos,

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so that's a fairly good name
for an asteroid

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that could
hit the Earth

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because that's exactly what
would happen.

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You'd have chaos,
destruction, and death.

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[Rowe] A catalog of devastation
to be
unleashed on Earth.

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But just how bad would
the impact be?

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[Rowe] January 2023.

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Asteroid Apep was on
a collision course with Earth.

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Step two in our
planetary defense --

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know your enemy and build up
a picture of the asteroid.

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Apep was 1,800 feet wide,

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Apep was 1,800 feet wide,

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five times the length of
a football field.

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Its huge size bumps it up into
a new category of asteroids.

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Apep was what we refer to as

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a PHA, a potentially
hazardous asteroid.

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We're talking about something

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that is a third of a mile
across.

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This is enormous.

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An 1,800-foot-wide asteroid is
about 112 million metric tons.

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An 1,800-foot-wide asteroid is
about 112 million metric tons.

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[Rowe]
That's over 300 times the weight
of the Empire State Building.

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Computer simulations
of the impact

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of an asteroid that massive
hitting a city

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revealed extraordinary levels
of destruction.

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An 1,800-foot-diameter asteroid,

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that
would create a crater

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that's 3 or 4 miles across,
1,600 feet deep.

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It would have a radiation
blast wave that

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It would have a radiation
blast wave that

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would set things on fire
for about 20 miles,

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but no sooner would things be
lit on fire,

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there would be
a 500-mile-an-hour wind

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radiating out,

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leveling buildings,
knocking down trees,

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destroying highways.

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100 miles away, you'd still feel
a magnitude seven earthquake.

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It's not easy to say what is
going to kill you first.

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It's probably going to be
simply the flash of energy.

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It's probably going to be
simply the flash of energy.

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There's so much heat from this
thing that you can be vaporized.

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If you somehow survived that,

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then there's going to be
the blast wave that will

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pulverize anything in its path.

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[Rowe] To build
an accurate simulation,

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the scientists used
more than size and mass.

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They also studied
its composition

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and the speed of its orbit.

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[Fast] You need to know what
an asteroid is made of,

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the speed of that asteroid,

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how large it is in order
to understand,

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how large it is in order
to understand,

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will it make it through
Earth's atmosphere,

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and what might the impact
effects be?

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[Rowe] Asteroids vary in
composition and structure.

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Some are loose collections
of small rocks,

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others rocky and compact.

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The most dangerous
are metallic.

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A metal asteroid can be five
times as dense

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as some of
the lower density asteroids,

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as some of
the lower density asteroids,

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and so for the same speeds
on the same orbits

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they pack way more punch
when it comes to an impact.

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[Thaller] If you want
to see exactly

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what a metallic asteroid
can do,

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go no farther than
Barringer Crater in Arizona.

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Now that crater is about
a mile across,

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and the meteor that made it was
only about 150 feet across.

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[Rowe] Arizona,
50,000 years ago.

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The last major asteroid strike
on present day North America,

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The last major asteroid strike
on present day North America,

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a tiny metallic space rock

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hits the ground
at 25,000 miles an hour,

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releasing energy equivalent to
2.5 million tons of TNT.

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Scale that up to the size of
1,800-foot Apep,

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and it would create a blast
wave the size of Delaware.

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If Apep were a metal
asteroid, it would tear through

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If Apep were a metal
asteroid, it would tear through

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the atmosphere
like a cosmic bullet.

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In a modern city,
without warning,

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it could kill a lot of people.

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But although
they're very dangerous,

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they're also very rare.

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[Rowe] More common are rubble
piles,

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00:12:34,567 --> 00:12:39,066
loose collections of small
rocks held together by gravity.

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Rubble pile is kind of
the perfect name for them,

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but you can think of them as
like a literally

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a pile of stuff out of a dump
truck in your driveway,

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but if you take that and you
put that in space,

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they don't have much gravity
but they have enough to stay

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bound to each other,

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and that's your rubble
pile asteroid.

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They are just barely holding
on to themselves.

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If you were to come and just
apply sufficient gravity,

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you could rip it apart.

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you could rip it apart.

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[Rowe] Pressure and heat from
entering our atmosphere

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can also tear a rubble
pile asteroid to pieces,

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but that can be just
as dangerous to a city below.

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The breakup of an asteroid in

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the upper atmosphere is --
is pretty devastating.

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It's like a nuclear weapon
going off in the atmosphere,

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flattening buildings
and breaking windows.

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flattening buildings
and breaking windows.

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There are going
to be mass casualties

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from an event like that

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due to just the injuries
from flying glass and debris.

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[Rowe] To discover what type of
asteroid Apep belonged to,

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00:13:59,367 --> 00:14:01,266
the planetary protection team

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00:14:01,367 --> 00:14:04,367
train their telescopes
onto the space rock.

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00:14:07,567 --> 00:14:10,367
Analysis revealed that Apep
was a rocky,

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00:14:10,367 --> 00:14:13,125
carbonaceous chondrite asteroid,
or C-type for short.

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00:14:13,125 --> 00:14:14,567
carbonaceous chondrite asteroid,
or C-type for short.

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00:14:17,066 --> 00:14:19,166
C-type asteroids like Apep

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00:14:19,166 --> 00:14:21,700
are less dense
than metal asteroids,

248
00:14:21,767 --> 00:14:24,767
but more solid than
rubble piles.

249
00:14:24,867 --> 00:14:27,100
If a big enough
C-type asteroid

250
00:14:27,166 --> 00:14:29,266
penetrates the Earth's
atmosphere,

251
00:14:29,266 --> 00:14:32,300
it has the chance to make it
all the way down to the surface.

252
00:14:32,367 --> 00:14:35,166
It doesn't necessarily burn up
in the atmosphere.

253
00:14:43,000 --> 00:14:43,125
[Rowe] Apep's size, mass, and
composition told us

254
00:14:43,125 --> 00:14:46,467
[Rowe] Apep's size, mass, and
composition told us

255
00:14:46,467 --> 00:14:50,100
it would punch through our
atmosphere and hit the surface.

256
00:14:54,100 --> 00:14:57,567
The final piece of information
needed to accurately predict

257
00:14:57,667 --> 00:15:00,266
the true amount of damage
from the impact

258
00:15:00,367 --> 00:15:04,467
was Apep's kinetic energy,
the amount of energy

259
00:15:04,567 --> 00:15:06,867
the asteroid would punch
into the ground.

260
00:15:09,166 --> 00:15:13,000
The kinetic energy of an object
depends on the mass,

261
00:15:13,066 --> 00:15:13,125
and it depends even
more strongly on the speed.

262
00:15:13,125 --> 00:15:16,567
and it depends even
more strongly on the speed.

263
00:15:16,567 --> 00:15:19,567
More mass creates more
kinetic energy,

264
00:15:19,667 --> 00:15:23,867
but more velocity will
increase the kinetic energy by

265
00:15:23,967 --> 00:15:25,467
a squared factor.

266
00:15:25,567 --> 00:15:28,800
For example, if something has
twice the velocity,

267
00:15:28,867 --> 00:15:32,166
it will have four times
the same energy.

268
00:15:32,266 --> 00:15:36,200
[Rowe] Scientists calculated how
much energy Apep,

269
00:15:36,266 --> 00:15:39,667
weighing in at 123 million tons

270
00:15:39,667 --> 00:15:42,200
and traveling at 40,000
miles an hour,

271
00:15:42,266 --> 00:15:43,125
would transfer into the Earth.

272
00:15:43,125 --> 00:15:45,567
would transfer into the Earth.

273
00:15:45,567 --> 00:15:47,600
So what kind of energies
were involved here?

274
00:15:47,667 --> 00:15:50,800
Uh, you know,
1,800-foot diameter asteroid.

275
00:15:50,867 --> 00:15:53,000
It's 112 million tons,

276
00:15:53,066 --> 00:15:55,867
and it's traveling
at 40,000 miles per hour.

277
00:15:55,967 --> 00:15:57,100
That's something
on the order of

278
00:15:57,166 --> 00:15:59,667
10 to the 19th
joules of energy,

279
00:15:59,667 --> 00:16:02,266
a one followed by 19 zeros.

280
00:16:10,266 --> 00:16:13,125
1.8 times 10 to the 19 joules
is equivalent to 5,000 megatons.

281
00:16:13,125 --> 00:16:16,300
1.8 times 10 to the 19 joules
is equivalent to 5,000 megatons.

282
00:16:16,367 --> 00:16:18,000
Take a one megaton nuke,

283
00:16:18,066 --> 00:16:23,367
a substantial nuclear weapon,
and then blow up 5,000 of them.

284
00:16:23,367 --> 00:16:27,200
That is roughly the same
amount as all the nuclear

285
00:16:27,266 --> 00:16:28,367
weapons on Earth,

286
00:16:28,467 --> 00:16:29,867
detonating all at once.

287
00:16:35,166 --> 00:16:38,000
[Rowe] A strike this large would
affect the whole planet.

288
00:16:40,700 --> 00:16:43,000
[Sutter] This would have
global impacts.

289
00:16:43,100 --> 00:16:43,125
We would have to deal with
the fallout,

290
00:16:43,125 --> 00:16:44,467
We would have to deal with
the fallout,

291
00:16:44,567 --> 00:16:47,300
the literal fallout
from this event for --

292
00:16:47,367 --> 00:16:49,166
for potentially
1,000 years.

293
00:16:53,200 --> 00:16:55,567
[Rowe] Spring, 2023.

294
00:16:55,667 --> 00:16:58,166
We had two choices --

295
00:16:58,166 --> 00:17:02,200
do nothing and face
a planet-changing catastrophe,

296
00:17:02,266 --> 00:17:04,700
or fight back.

297
00:17:04,767 --> 00:17:07,166
We chose to take on Apep.

298
00:17:08,667 --> 00:17:11,567
It was the first time
in human history

299
00:17:11,567 --> 00:17:13,125
that we might actually be able
to prevent a natural disaster

300
00:17:13,125 --> 00:17:15,100
that we might actually be able
to prevent a natural disaster

301
00:17:15,166 --> 00:17:16,667
from happening.

302
00:17:16,767 --> 00:17:20,166
We could plan and launch
a response mission,

303
00:17:20,166 --> 00:17:21,667
so we don't have
to get out of the way.

304
00:17:21,767 --> 00:17:23,900
Make it get
out of the way instead.

305
00:17:26,867 --> 00:17:29,700
[Rowe] The mission's objective
was simple --

306
00:17:29,767 --> 00:17:33,467
stop the asteroid,
and save the world.

307
00:17:35,767 --> 00:17:38,567
We can't superglue
an earthquake fault shut.

308
00:17:38,567 --> 00:17:41,467
We can't cork volcanoes,

309
00:17:41,567 --> 00:17:43,125
but planning
for an asteroid impact

310
00:17:43,125 --> 00:17:44,266
but planning
for an asteroid impact

311
00:17:44,367 --> 00:17:46,100
is something
we really could do.

312
00:17:55,367 --> 00:17:57,600
[Rowe] June 2023.

313
00:17:59,600 --> 00:18:04,667
A large asteroid
was headed towards Earth.

314
00:18:04,767 --> 00:18:09,100
It was predicted to strike on
November 4, 2029.

315
00:18:16,467 --> 00:18:17,567
To protect our planet,

316
00:18:17,600 --> 00:18:18,500
A team of scientists plan to
deflect the asteroid.

317
00:18:18,500 --> 00:18:25,367
A team of scientists plan to
deflect the asteroid.

318
00:18:25,467 --> 00:18:27,667
[Sutter]
An 1,800-foot wide asteroid

319
00:18:27,767 --> 00:18:29,467
was headed towards the Earth.

320
00:18:29,567 --> 00:18:34,567
We needed it to go in
literally any other direction.

321
00:18:34,667 --> 00:18:37,667
[Rowe] So how could we
push Apep off course?

322
00:18:39,166 --> 00:18:44,867
Scientists found a clue in
the asteroid belt.

323
00:18:47,900 --> 00:18:48,500
Sometimes the lumps
of space debris collide

324
00:18:48,500 --> 00:18:51,400
Sometimes the lumps
of space debris collide

325
00:18:51,467 --> 00:18:54,567
and change their trajectory.

326
00:18:54,567 --> 00:18:59,700
Maybe we could replicate this
and deflect Apep.

327
00:18:59,767 --> 00:19:02,200
We could try to deflect the
asteroid and change its orbit

328
00:19:02,266 --> 00:19:04,600
so that it actually
misses the Earth.

329
00:19:04,667 --> 00:19:06,400
[Sutter]
If you do it early enough,

330
00:19:06,467 --> 00:19:10,400
it may not be much, less than
half a millimeter per second,

331
00:19:10,467 --> 00:19:12,967
but that is enough.

332
00:19:12,967 --> 00:19:17,800
These asteroids travel for
millions of miles, and so over

333
00:19:17,867 --> 00:19:18,500
the course of days, weeks,

334
00:19:18,500 --> 00:19:19,667
the course of days, weeks,

335
00:19:19,667 --> 00:19:24,000
months, and years, it will have
a radically different orbit.

336
00:19:25,066 --> 00:19:26,567
[Rowe] Sounds simple.

337
00:19:26,667 --> 00:19:30,000
Send up a rocket with
a robotic space probe,

338
00:19:30,066 --> 00:19:34,567
travel millions of miles,
and knock Apep away from Earth.

339
00:19:35,867 --> 00:19:36,767
Piece of cake.

340
00:19:38,867 --> 00:19:39,934
In the movies,

341
00:19:40,000 --> 00:19:42,166
when there's a threatening
asteroid that's found,

342
00:19:42,266 --> 00:19:45,967
there's always a rocket on
the pad ready to go after that,

343
00:19:45,967 --> 00:19:48,500
and it's not the case
in real life.

344
00:19:48,500 --> 00:19:48,767
and it's not the case
in real life.

345
00:19:48,867 --> 00:19:51,166
It takes years
to design the mission,

346
00:19:51,166 --> 00:19:53,400
to build the satellite,
to launch it,

347
00:19:53,467 --> 00:19:54,867
and then it has to get there,

348
00:19:54,867 --> 00:19:57,867
and that might be millions
of miles away from Earth.

349
00:19:59,000 --> 00:20:01,367
[Rowe] Fortunately,
Earth had a head start.

350
00:20:02,700 --> 00:20:05,000
We detected Apep early,

351
00:20:07,367 --> 00:20:12,066
and we'd already built
an asteroid deflector called

352
00:20:12,066 --> 00:20:15,266
the Double Asteroid
Redirection Test,

353
00:20:15,266 --> 00:20:17,500
or DART for short.

354
00:20:19,500 --> 00:20:24,100
In 2021 we sent DART
6.8 million miles

355
00:20:24,166 --> 00:20:27,700
to rendezvous with
an asteroid called Didymos.

356
00:20:28,867 --> 00:20:31,500
Didymos posed
no threat to Earth,

357
00:20:31,567 --> 00:20:33,967
but allowed us
to test the technology.

358
00:20:35,467 --> 00:20:36,867
[Thaller]
The asteroid called Didymos

359
00:20:36,967 --> 00:20:40,200
has a small moon asteroid
going around it.

360
00:20:40,266 --> 00:20:41,300
The point of the DART mission

361
00:20:41,367 --> 00:20:44,200
was to send an impactor
into this little moon

362
00:20:44,266 --> 00:20:47,100
and see how much we nudge
it off the orbit that it's in.

363
00:20:48,667 --> 00:20:50,967
[Rowe] Lessons learned
from DART

364
00:20:50,967 --> 00:20:53,200
would inspire a new mission.

365
00:20:56,066 --> 00:20:58,767
November 2025.

366
00:20:58,767 --> 00:21:01,467
We launched
the DAAFE mission --

367
00:21:01,467 --> 00:21:06,066
deflect Apep
away from Earth.

368
00:21:06,066 --> 00:21:09,367
This wasn't a test run to
a safe asteroid.

369
00:21:09,467 --> 00:21:12,967
This was the real deal,
a mission to save our planet.

370
00:21:12,967 --> 00:21:17,100
It was an enormous
technical challenge,

371
00:21:17,166 --> 00:21:18,500
and we had no idea
if it would work.

372
00:21:18,500 --> 00:21:20,000
and we had no idea
if it would work.

373
00:21:21,200 --> 00:21:25,000
When you think about
a spacecraft going from Earth

374
00:21:25,066 --> 00:21:28,100
millions of miles away
to hit an asteroid

375
00:21:28,166 --> 00:21:29,767
at an exact point
in time,

376
00:21:29,767 --> 00:21:30,967
at an exact point in space.

377
00:21:30,967 --> 00:21:33,367
It's really
the ultimate bullseye.

378
00:21:33,367 --> 00:21:37,100
It's like trying to hit one
bullet with another bullet

379
00:21:37,166 --> 00:21:39,367
launched from the other
side of a continent.

380
00:21:41,667 --> 00:21:43,667
[Rowe] November 2028.

381
00:21:44,767 --> 00:21:48,500
After three years in space,
DAAFE arrived at Apep.

382
00:21:48,500 --> 00:21:50,000
After three years in space,
DAAFE arrived at Apep.

383
00:21:52,467 --> 00:21:54,367
This was our last chance.

384
00:21:54,367 --> 00:21:56,000
This was our only chance.

385
00:21:59,266 --> 00:22:00,266
[Rowe] The kinetic impactor

386
00:22:00,266 --> 00:22:04,166
smashed into Apep
at 14,000 miles an hour.

387
00:22:10,800 --> 00:22:14,200
On Earth, telescopes and radar
tracked the collision.

388
00:22:15,800 --> 00:22:16,967
Did it work?

389
00:22:16,967 --> 00:22:18,500
Did we push the asteroid
off course?

390
00:22:18,500 --> 00:22:20,467
Did we push the asteroid
off course?

391
00:22:20,567 --> 00:22:22,467
At first glance, the
mission worked.

392
00:22:22,567 --> 00:22:25,767
We deflected Apep away
from us.

393
00:22:28,000 --> 00:22:29,667
[Rowe] It looked like the
mission worked.

394
00:22:32,800 --> 00:22:34,667
[Plait] As an astronomer,
and, you know,

395
00:22:34,667 --> 00:22:36,867
a human who has to live
on this planet,

396
00:22:36,967 --> 00:22:38,300
I was very happy, right?

397
00:22:38,367 --> 00:22:41,000
We've just literally
saved the world.

398
00:22:41,066 --> 00:22:43,667
[Rowe] But the happiness
was short-lived.

399
00:22:44,767 --> 00:22:46,000
There was a problem.

400
00:22:46,100 --> 00:22:48,500
The collision had pushed Apep
away from Earth,

401
00:22:48,500 --> 00:22:49,767
The collision had pushed Apep
away from Earth,

402
00:22:53,266 --> 00:22:57,667
but it also sheared off
a 300-foot chunk of rock.

403
00:22:59,367 --> 00:23:03,400
This smaller asteroid,
called Apep 2.0,

404
00:23:03,467 --> 00:23:05,166
could still be
a significant threat.

405
00:23:08,266 --> 00:23:13,100
A 300-foot chunk of rock
is still very, very large.

406
00:23:13,166 --> 00:23:14,667
300 feet wide.

407
00:23:14,767 --> 00:23:17,000
That's almost
a football field.

408
00:23:18,100 --> 00:23:18,500
[Plesko] So the important things
we needed to know --

409
00:23:18,500 --> 00:23:19,967
[Plesko] So the important things
we needed to know --

410
00:23:19,967 --> 00:23:21,567
was it going to hit us?

411
00:23:22,600 --> 00:23:24,800
And if so, where is it going
to hit us?

412
00:23:26,900 --> 00:23:31,066
[Rowe] March 2029,
we got our answer.

413
00:23:31,066 --> 00:23:33,266
Its point of impact --

414
00:23:33,367 --> 00:23:36,000
The east coast
of the United States,

415
00:23:37,600 --> 00:23:40,767
with New York City
in the firing line.

416
00:23:43,500 --> 00:23:46,066
SUTTER: A smaller chunk headed
for New York City.

417
00:23:47,200 --> 00:23:48,500
This was
the worst-case scenario.

418
00:23:48,500 --> 00:23:50,066
This was
the worst-case scenario.

419
00:23:59,000 --> 00:24:00,166
I want to emphasize,

420
00:24:00,166 --> 00:24:02,467
there's no asteroid
headed toward New York tonight.

421
00:24:02,467 --> 00:24:05,367
This is just
a discussion about

422
00:24:05,467 --> 00:24:07,367
what this process would
be like.

423
00:24:15,567 --> 00:24:16,867
[Rowe] In 2028,

424
00:24:16,867 --> 00:24:19,900
we tried to deflect
Apep away from Earth.

425
00:24:22,166 --> 00:24:23,999
The mission wasn't
a complete success.

426
00:24:23,999 --> 00:24:26,767
The mission wasn't
a complete success.

427
00:24:26,867 --> 00:24:28,767
Yes, we managed to
actually divert

428
00:24:28,767 --> 00:24:31,500
the large asteroid away from
hitting the Earth,

429
00:24:31,567 --> 00:24:34,367
but in doing so, we broke off
a clump big enough

430
00:24:34,467 --> 00:24:37,300
to be very dangerous heading
toward the eastern seaboard.

431
00:24:39,667 --> 00:24:44,300
[Rowe] June 2029,
five months to impact.

432
00:24:46,367 --> 00:24:48,867
The future looked bleak for
New York,

433
00:24:48,967 --> 00:24:50,767
but it wasn't the time
to give up.

434
00:24:52,000 --> 00:24:53,667
They reassessed an idea

435
00:24:53,667 --> 00:24:53,999
first suggested to destroy
the original 1,800-foot Apep,

436
00:24:53,999 --> 00:25:00,066
first suggested to destroy
the original 1,800-foot Apep,

437
00:25:00,066 --> 00:25:01,467
a nuclear strike.

438
00:25:03,800 --> 00:25:05,266
It worked in Armageddon.

439
00:25:05,266 --> 00:25:07,266
Maybe it would work in
real life.

440
00:25:08,600 --> 00:25:12,266
However, studies revealed
that nuking an asteroid

441
00:25:12,367 --> 00:25:16,467
wasn't as simple as it looks
in a Hollywood movie.

442
00:25:16,467 --> 00:25:17,467
Hey, let's blow it up.

443
00:25:17,567 --> 00:25:18,667
Let's nuke it, right?

444
00:25:18,667 --> 00:25:20,667
Well, instead of one
big problem,

445
00:25:20,667 --> 00:25:22,500
now you have
slightly smaller problems,

446
00:25:22,567 --> 00:25:23,999
and they're radioactive,
by the way.

447
00:25:23,999 --> 00:25:24,900
and they're radioactive,
by the way.

448
00:25:25,000 --> 00:25:26,166
So you don't want to do that.

449
00:25:28,000 --> 00:25:30,500
[Rowe]
Computer simulations revealed

450
00:25:30,567 --> 00:25:32,166
that even the world's largest

451
00:25:32,166 --> 00:25:36,367
nuclear weapon had only
1 percent of the energy needed

452
00:25:36,367 --> 00:25:40,266
to destroy the original
1,800-foot Apep.

453
00:25:42,166 --> 00:25:46,100
We needed the world's most
powerful nuclear weapon

454
00:25:46,166 --> 00:25:50,700
and 99 of its best friends,
launch them all simultaneously,

455
00:25:50,767 --> 00:25:53,999
and have them simultaneously
hit the asteroid.

456
00:25:53,999 --> 00:25:54,200
and have them simultaneously
hit the asteroid.

457
00:25:54,266 --> 00:25:57,600
It was simply beyond our
technological capabilities.

458
00:26:00,300 --> 00:26:02,467
[Rowe] Fortunately,
thanks to the DAAFE mission,

459
00:26:02,467 --> 00:26:06,567
we only had to take out
the 300-foot Apep 2.0.

460
00:26:12,100 --> 00:26:15,166
Could we blow the smaller
asteroid out of the sky?

461
00:26:19,100 --> 00:26:22,667
Maybe, but launching
a nuclear Hail Mary

462
00:26:22,767 --> 00:26:23,999
would be
very controversial.

463
00:26:23,999 --> 00:26:24,500
would be
very controversial.

464
00:26:26,500 --> 00:26:31,166
Nuclear devices
are the most powerful,

465
00:26:31,166 --> 00:26:32,867
really, one of the
most emotional

466
00:26:32,867 --> 00:26:35,900
things that humans have
ever invented.

467
00:26:39,767 --> 00:26:43,300
[Rivkin] They are the most
powerful tool in our toolbox.

468
00:26:43,367 --> 00:26:46,367
We've got a hammer,
and it's a very big hammer,

469
00:26:46,467 --> 00:26:49,767
but there are a lot of
concerns with them,

470
00:26:49,867 --> 00:26:53,266
so they cannot be
tested in space,

471
00:26:53,367 --> 00:26:53,999
according to international law.

472
00:26:53,999 --> 00:26:55,000
according to international law.

473
00:26:56,567 --> 00:26:59,767
[Rowe] Without being able
to test nukes in space,

474
00:26:59,867 --> 00:27:01,667
they were considered
too big a risk,

475
00:27:06,100 --> 00:27:10,166
but New York had one final
potential savior,

476
00:27:11,400 --> 00:27:13,166
the Earth itself.

477
00:27:16,900 --> 00:27:20,000
2013, Chelyabinsk, Russia.

478
00:27:21,600 --> 00:27:23,999
An asteroid blew up
in the atmosphere.

479
00:27:23,999 --> 00:27:24,266
An asteroid blew up
in the atmosphere.

480
00:27:26,600 --> 00:27:28,767
It didn't make it all the way
to the surface,

481
00:27:28,767 --> 00:27:31,467
and the people in Chelyabinsk
are very lucky because of that.

482
00:27:33,100 --> 00:27:36,100
[Rowe] The 60-foot-wide
Chelyabinsk asteroid

483
00:27:36,166 --> 00:27:38,166
was rocky like Apep,

484
00:27:39,000 --> 00:27:41,000
and it moved
at a similar velocity,

485
00:27:41,100 --> 00:27:43,000
around 40,000 miles an hour,

486
00:27:44,867 --> 00:27:50,600
but it met its match when it
entered Earth's atmosphere.

487
00:27:50,667 --> 00:27:52,667
Earth's atmosphere
doesn't look like much.

488
00:27:52,767 --> 00:27:53,999
You think, oh, it's just air,
it doesn't matter,

489
00:27:53,999 --> 00:27:54,667
You think, oh, it's just air,
it doesn't matter,

490
00:27:54,767 --> 00:27:57,367
but all of those molecules
actually exert pressure

491
00:27:57,367 --> 00:27:58,867
on the front edge
of the asteroid,

492
00:27:58,967 --> 00:28:02,266
slowing it down
and heating it up.

493
00:28:02,266 --> 00:28:03,367
Rock heated up

494
00:28:03,467 --> 00:28:07,767
and began to crumble and explode
as it came through.

495
00:28:07,867 --> 00:28:10,567
[Rowe] The midair explosion,
called an airburst,

496
00:28:10,567 --> 00:28:15,166
released more energy
than 440,000 tons of TNT.

497
00:28:21,500 --> 00:28:23,767
The shockwave traveled
100 miles,

498
00:28:24,800 --> 00:28:27,300
damaging 7,000 buildings

499
00:28:27,367 --> 00:28:29,266
and injuring 1,500 people.

500
00:28:30,700 --> 00:28:33,200
But a ground strike
hitting a city

501
00:28:33,266 --> 00:28:34,467
would have been a lot worse.

502
00:28:42,300 --> 00:28:46,500
Apep 2.0 was five times larger
than the Chelyabinsk Rock.

503
00:28:48,700 --> 00:28:50,367
Would it break up during its

504
00:28:50,467 --> 00:28:53,867
10-second trip down
through the atmosphere,

505
00:28:53,967 --> 00:28:53,999
or would it pierce
right through?

506
00:28:53,999 --> 00:28:58,367
or would it pierce
right through?

507
00:28:58,467 --> 00:29:01,500
The planetary defense team
ran simulations.

508
00:29:03,667 --> 00:29:07,000
As that comes through
Earth's atmosphere,

509
00:29:07,100 --> 00:29:10,000
some of that hot air can get
into the cracks.

510
00:29:11,066 --> 00:29:14,467
[Rowe] Friction and pressure
would heat Apep 2.0's

511
00:29:14,567 --> 00:29:17,867
surface to thousands of
degrees Fahrenheit.

512
00:29:19,100 --> 00:29:22,000
At those temperatures,
even rock burns.

513
00:29:23,300 --> 00:29:23,999
We would see this
flaming monster

514
00:29:23,999 --> 00:29:26,467
We would see this
flaming monster

515
00:29:26,567 --> 00:29:30,767
of death coming racing
through our atmosphere.

516
00:29:30,767 --> 00:29:34,166
There are gonna be pieces of
debris vaporizing

517
00:29:34,266 --> 00:29:35,567
and coming off of it.

518
00:29:35,567 --> 00:29:37,667
So you get these flashes of
light that happen

519
00:29:37,767 --> 00:29:39,367
one after another -- pop, pop,
pop, pop, pop, pop, pop,

520
00:29:39,367 --> 00:29:40,900
as these things
are blowing up.

521
00:29:46,667 --> 00:29:48,066
[Rowe]
The computer simulations

522
00:29:48,066 --> 00:29:50,000
showed that the extra bulk of

523
00:29:50,100 --> 00:29:53,767
Apep 2.0 would stop it from
blowing up.

524
00:29:57,100 --> 00:29:59,800
Some of the asteroid would
blast away,

525
00:29:59,867 --> 00:30:01,900
but most of the space rock

526
00:30:02,000 --> 00:30:05,600
would reach the
Earth's surface.

527
00:30:05,667 --> 00:30:07,800
So that close to the
actual impact,

528
00:30:07,867 --> 00:30:10,200
we pretty much just had to
hunker down and take it.

529
00:30:13,567 --> 00:30:16,400
[Rowe] The prospects for
New York City were grim.

530
00:30:18,100 --> 00:30:20,300
It was facing annihilation.

531
00:30:32,667 --> 00:30:35,166
[Rowe] October 2029.

532
00:30:35,266 --> 00:30:39,367
Three weeks to impact.

533
00:30:39,467 --> 00:30:42,800
For the citizens of the New York
metropolitan area,

534
00:30:42,867 --> 00:30:47,867
there was only one goal --
Get out of the firing line.

535
00:30:52,567 --> 00:30:53,567
Now we had to have

536
00:30:53,600 --> 00:30:56,024
the plans in place
to evacuate these cities.

537
00:30:56,024 --> 00:30:57,000
the plans in place
to evacuate these cities.

538
00:30:57,100 --> 00:31:01,500
It was a major emergency for
New York and its citizens.

539
00:31:01,567 --> 00:31:04,200
Time to move out of the way.

540
00:31:05,567 --> 00:31:08,467
[Rowe] To work out who
should evacuate and to where,

541
00:31:08,567 --> 00:31:10,600
Scientists ran detailed
projections

542
00:31:10,667 --> 00:31:14,400
of the potential blast area.

543
00:31:14,467 --> 00:31:17,467
There's an ellipse there that
we call the hazard ellipse that

544
00:31:17,567 --> 00:31:21,600
says somewhere in this area is
where the asteroid will hit.

545
00:31:21,667 --> 00:31:23,467
That means there's
a little wiggle room

546
00:31:23,567 --> 00:31:26,024
and a range of areas
that are in danger.

547
00:31:26,024 --> 00:31:26,100
and a range of areas
that are in danger.

548
00:31:28,066 --> 00:31:31,166
[Rowe] Based on the hazard
ellipse projections,

549
00:31:31,266 --> 00:31:34,100
the government issued
evacuation orders

550
00:31:34,166 --> 00:31:36,767
for the tri-state area,

551
00:31:36,867 --> 00:31:39,567
and as far south
as Philadelphia.

552
00:31:39,567 --> 00:31:43,667
It was the biggest evacuation
in US history.

553
00:31:43,667 --> 00:31:46,567
Millions were displaced.

554
00:31:46,667 --> 00:31:49,066
It was physically horrific.

555
00:31:51,300 --> 00:31:54,266
I live in the New York
metropolitan area.

556
00:31:54,266 --> 00:31:56,024
It was horrible for me and my
family and my friends,

557
00:31:56,024 --> 00:31:57,266
It was horrible for me and my
family and my friends,

558
00:31:57,266 --> 00:32:01,800
but we can't just sit here and
cross our fingers and hope that

559
00:32:01,867 --> 00:32:03,300
we don't get struck.

560
00:32:04,867 --> 00:32:07,367
[Rowe] The freeways out of the
city were jammed.

561
00:32:11,767 --> 00:32:14,000
Trains were packed.

562
00:32:14,100 --> 00:32:16,867
Over 23 million
people evacuated,

563
00:32:17,967 --> 00:32:20,567
leaving behind
a deserted city.

564
00:32:23,166 --> 00:32:25,767
Computer models
show that the epicenter

565
00:32:25,767 --> 00:32:26,024
of the strike
would be Manhattan.

566
00:32:26,024 --> 00:32:27,800
of the strike
would be Manhattan.

567
00:32:31,000 --> 00:32:35,200
The blast would reduce
the city to rubble and ash.

568
00:32:36,266 --> 00:32:39,300
There would be a one-mile-wide
crater resulting from it,

569
00:32:39,367 --> 00:32:41,367
so deep that
it would actually take

570
00:32:41,467 --> 00:32:44,767
the entire subway system and
turn it upside down and lay it

571
00:32:44,867 --> 00:32:47,700
onto the rim of the crater.

572
00:32:47,767 --> 00:32:50,166
You would have
a magnitude 5 earthquake

573
00:32:50,166 --> 00:32:52,266
at even six miles away
from that,

574
00:32:52,367 --> 00:32:54,467
and there would be
a big air blast,

575
00:32:54,467 --> 00:32:56,024
400-mile-an-hour winds.

576
00:32:56,024 --> 00:32:56,367
400-mile-an-hour winds.

577
00:32:57,800 --> 00:33:00,400
Something as light as a pencil
could be a lethal weapon

578
00:33:00,467 --> 00:33:02,266
when picked up by a shock wave
like that.

579
00:33:03,800 --> 00:33:07,767
As the crater is blasting out
and excavating itself,

580
00:33:07,867 --> 00:33:13,467
there would be little blobs of
molten rock that get thrown out

581
00:33:13,567 --> 00:33:16,300
in this wave, going faster than
the speed of sound,

582
00:33:18,266 --> 00:33:19,700
Like drops a fiery rain,

583
00:33:19,767 --> 00:33:22,667
if you will, landing back miles
away from the crater.

584
00:33:27,767 --> 00:33:29,800
[Rowe]
The city would be on fire.

585
00:33:32,266 --> 00:33:35,567
So, um, there's just
no upside to this.

586
00:33:35,667 --> 00:33:36,567
There's nothing good.

587
00:33:36,600 --> 00:33:38,900
It's just all
from bad to horrific.

588
00:33:40,900 --> 00:33:43,567
[Rowe]
But New York is by the ocean.

589
00:33:43,567 --> 00:33:48,266
What would happen if Apep 2.0
hit the sea?

590
00:33:52,567 --> 00:33:56,000
Detailed simulations have
revealed two very

591
00:33:56,066 --> 00:33:57,166
different outcomes

592
00:33:57,166 --> 00:34:00,867
for an asteroid hitting
the ocean at high speeds.

593
00:34:04,400 --> 00:34:07,467
SUTTER: If a giant asteroid
strikes the deep ocean,

594
00:34:07,567 --> 00:34:09,600
less than 1 percent
of its energy

595
00:34:09,667 --> 00:34:11,467
gets converted into waves.

596
00:34:11,467 --> 00:34:13,767
Those waves quickly disperse.

597
00:34:13,867 --> 00:34:16,567
They quickly lose energy as
they travel.

598
00:34:16,567 --> 00:34:20,467
By the time they reach
the coast, it might just be

599
00:34:20,467 --> 00:34:21,467
a little ripple,

600
00:34:21,567 --> 00:34:23,500
you might not even be able to
surf on it.

601
00:34:29,667 --> 00:34:32,467
[Rowe] If the asteroid hit
shallow coastal waters,

602
00:34:34,867 --> 00:34:37,700
it could cause significant
damage along the shoreline.

603
00:34:39,467 --> 00:34:43,300
If an asteroid, the size of
Apep hits the continental shelf

604
00:34:43,367 --> 00:34:45,367
where the water is
relatively shallow,

605
00:34:45,367 --> 00:34:48,467
then it could potentially
cause a tsunami.

606
00:34:52,700 --> 00:34:54,867
[Rowe] But that would just be
the start of the problems.

607
00:34:58,200 --> 00:34:59,867
With a shallow water impactor,

608
00:34:59,867 --> 00:35:03,200
huge amounts of steam are
generated basically by

609
00:35:03,266 --> 00:35:06,667
the energy of that impactor
vaporizing all the water.

610
00:35:06,667 --> 00:35:08,967
Well, all the water is then put
up into the atmosphere,

611
00:35:08,967 --> 00:35:12,266
and water is a really good
greenhouse gas.

612
00:35:12,367 --> 00:35:14,166
So you have warming from
the launch of water

613
00:35:14,166 --> 00:35:15,200
up into the atmosphere.

614
00:35:15,266 --> 00:35:17,867
You have cooling
from all of the ash and dust.

615
00:35:24,266 --> 00:35:25,266
[Rowe]
A short bout of warming

616
00:35:25,367 --> 00:35:26,024
would be followed
by a brutal winter.

617
00:35:26,024 --> 00:35:27,667
would be followed
by a brutal winter.

618
00:35:29,166 --> 00:35:31,800
Crops would fail.

619
00:35:31,867 --> 00:35:37,800
This impact has so many
horrible follow-on consequences.

620
00:35:37,867 --> 00:35:40,767
That tells us how difficult
it would be to --

621
00:35:40,867 --> 00:35:43,667
to rebuild from an event
like this.

622
00:35:47,600 --> 00:35:48,667
[Rowe] The eastern seaboard

623
00:35:48,667 --> 00:35:52,066
would suffer a serious economic
downturn.

624
00:35:52,066 --> 00:35:54,166
It would take decades
to recover.

625
00:35:59,200 --> 00:36:01,100
November 3rd, 2029.

626
00:36:02,500 --> 00:36:04,567
One day until impact.

627
00:36:06,400 --> 00:36:09,667
The space rock was just
400,000 miles away,

628
00:36:10,667 --> 00:36:16,000
and traveling 13 times faster
than an F-15 fighter jet.

629
00:36:16,100 --> 00:36:20,367
It was first a dim star,
and then a brighter star,

630
00:36:20,467 --> 00:36:23,166
and then in the hours before,
you can actually see it

631
00:36:23,266 --> 00:36:24,367
approaching the Earth.

632
00:36:25,867 --> 00:36:26,024
[Rowe]
New York looked outmatched.

633
00:36:26,024 --> 00:36:28,700
[Rowe]
New York looked outmatched.

634
00:36:28,767 --> 00:36:31,700
It looked like Apep
would win,

635
00:36:31,767 --> 00:36:34,600
but this was not the end of
the game.

636
00:36:34,667 --> 00:36:37,467
Earth had one final card
to play.

637
00:36:49,467 --> 00:36:51,567
[Rowe]
November 4th, 2029.

638
00:36:53,500 --> 00:36:57,300
The 300-foot Apep 2.0
reached Earth.

639
00:36:59,800 --> 00:37:01,367
The space rock pierced our

640
00:37:01,367 --> 00:37:05,166
atmosphere and hurtled
towards the surface.

641
00:37:18,100 --> 00:37:22,000
Then the asteroid passed
over Manhattan,

642
00:37:24,367 --> 00:37:27,066
over Brooklyn,

643
00:37:27,066 --> 00:37:28,767
and over Coney Island.

644
00:37:31,100 --> 00:37:35,400
It hit deep ocean,
350 miles off the coast.

645
00:37:42,200 --> 00:37:45,767
Apep 2.0 missed New York.

646
00:37:45,767 --> 00:37:46,667
But how?

647
00:37:50,300 --> 00:37:52,200
Our 7-year battle with
the asteroid

648
00:37:52,266 --> 00:37:55,166
resolved in a matter
of seconds

649
00:37:55,166 --> 00:37:58,200
thanks to orbital dynamics.

650
00:37:59,300 --> 00:38:01,567
The orbit of the asteroid
and the orbit of the Earth

651
00:38:01,667 --> 00:38:05,400
and the way the Earth spins in
this great cosmic ballet

652
00:38:05,467 --> 00:38:06,700
means that

653
00:38:06,767 --> 00:38:10,266
a few seconds earlier or later
makes the difference between

654
00:38:10,266 --> 00:38:11,699
hitting the ocean
and hitting land.

655
00:38:11,699 --> 00:38:12,400
hitting the ocean
and hitting land.

656
00:38:13,800 --> 00:38:16,266
[Rowe] Earth rotates at
1,000 miles an hour

657
00:38:17,700 --> 00:38:22,567
and orbits the sun at close
to 65,000 miles an hour.

658
00:38:22,567 --> 00:38:26,700
Apep orbited
at 40,000 miles an hour,

659
00:38:26,767 --> 00:38:31,467
but Apep 2.0 traveled
fractionally slower.

660
00:38:33,266 --> 00:38:36,166
The impact of the DAAFE mission
that sheared off

661
00:38:36,266 --> 00:38:41,367
the 300-foot chunk of rock
had also slowed it down.

662
00:38:41,467 --> 00:38:41,699
Slowing down Apep

663
00:38:41,699 --> 00:38:42,867
Slowing down Apep

664
00:38:42,967 --> 00:38:45,166
changed when it's going to
intersect the Earth.

665
00:38:45,266 --> 00:38:47,100
So New York spun out of
the crosshairs.

666
00:38:51,700 --> 00:38:56,066
[Rowe] Apep 2.0, hit
the ocean and exploded,

667
00:38:56,066 --> 00:38:57,667
breaking up instantly.

668
00:39:00,100 --> 00:39:03,467
The strike threw up a wall of
water into the air,

669
00:39:03,467 --> 00:39:05,667
followed by huge clouds
of steam.

670
00:39:07,500 --> 00:39:11,000
The impact created small
surface waves that quickly

671
00:39:11,066 --> 00:39:11,699
died away.

672
00:39:11,699 --> 00:39:12,200
died away.

673
00:39:13,600 --> 00:39:17,700
It's like doing a gigantic
interplanetary belly flop.

674
00:39:17,767 --> 00:39:20,767
It evaporates, it obliterates,
and it generates

675
00:39:20,767 --> 00:39:23,500
an enormous amount of steam,
and it sets up shock waves.

676
00:39:23,567 --> 00:39:25,266
All that energy is still
released,

677
00:39:25,367 --> 00:39:28,467
but the ocean is capable of
absorbing it.

678
00:39:31,767 --> 00:39:35,600
[Rowe] New York dodged the
bullet and escaped unscathed

679
00:39:37,266 --> 00:39:40,400
thanks to the
dedication, ingenuity,

680
00:39:40,467 --> 00:39:41,699
and enterprise of a global
team of scientists.

681
00:39:41,699 --> 00:39:48,200
and enterprise of a global
team of scientists.

682
00:39:50,500 --> 00:39:54,667
Apep was an
imaginary asteroid,

683
00:39:54,767 --> 00:39:58,700
but there are many potentially
hazardous space rocks out there.

684
00:40:01,467 --> 00:40:04,266
Thankfully,
this was a fictional scenario.

685
00:40:04,367 --> 00:40:07,867
It's a thought exercise, but
it's informed by our real,

686
00:40:07,967 --> 00:40:11,000
actual knowledge we've gained
over the years of dealing with,

687
00:40:11,066 --> 00:40:11,699
you know, potential close
approaches and the hazard from

688
00:40:11,699 --> 00:40:13,900
you know, potential close
approaches and the hazard from

689
00:40:14,000 --> 00:40:18,266
real asteroids that we actually
know about.

690
00:40:18,266 --> 00:40:21,867
Asteroid research is a good
insurance policy

691
00:40:21,967 --> 00:40:23,567
for our species.

692
00:40:23,567 --> 00:40:27,066
Hopefully we will never need
to carry these things out

693
00:40:27,066 --> 00:40:28,567
for real.

694
00:40:28,567 --> 00:40:30,867
[Rowe] Large
asteroid strikes are rare,

695
00:40:32,300 --> 00:40:34,066
but we cannot be complacent.

696
00:40:39,266 --> 00:40:41,699
The most important thing to
do in planetary defense

697
00:40:41,699 --> 00:40:42,667
The most important thing to
do in planetary defense

698
00:40:42,767 --> 00:40:44,400
is to find them early.

699
00:40:44,467 --> 00:40:46,767
If we find them early, we have
a chance to predict

700
00:40:46,767 --> 00:40:49,600
the possible impacts and we
have a chance to mitigate them.

701
00:40:54,767 --> 00:40:56,600
[Rowe]
Our technology is improving,

702
00:40:58,066 --> 00:41:01,400
so we can detect incoming
space rocks earlier,

703
00:41:03,667 --> 00:41:06,200
but we need to be vigilant,

704
00:41:06,266 --> 00:41:10,767
because the threat from
asteroids is not going away.

705
00:41:12,066 --> 00:41:13,567
Apart from climate change,

706
00:41:13,567 --> 00:41:17,166
asteroid strikes are, in my
opinion, the most dangerous

707
00:41:17,166 --> 00:41:18,567
thing to life on Earth.

708
00:41:19,867 --> 00:41:21,767
[Plait] A lot of the times
the question I get is,

709
00:41:21,867 --> 00:41:23,767
"What are the chances of this
happening?"

710
00:41:23,867 --> 00:41:26,567
And they don't like the answer
because I say 100 percent.

711
00:41:28,700 --> 00:41:29,867
It takes time.

712
00:41:29,900 --> 00:41:33,000
It may not be for a week,
a month, a year, a century.

713
00:41:33,066 --> 00:41:35,467
But studying these asteroids
informs us on

714
00:41:35,567 --> 00:41:37,400
what we can do
to prevent an impact.

715
00:41:39,000 --> 00:41:41,266
There are a lot of natural
disasters that we can do

716
00:41:41,266 --> 00:41:41,699
nothing about --
earthquakes, hurricanes,

717
00:41:41,699 --> 00:41:43,400
nothing about --
earthquakes, hurricanes,

718
00:41:43,467 --> 00:41:44,367
that sort of thing.

719
00:41:44,367 --> 00:41:46,567
Here is
something way more devastating

720
00:41:46,667 --> 00:41:50,400
than any of those,
and we can prevent them.

721
00:41:50,467 --> 00:41:52,600
So we have to keep our eyes on

722
00:41:52,667 --> 00:41:54,767
the prize and our eyes on
the skies.