In a fictional scenario set in 2029, an asteroid hurtling towards Earth at 40,000 mph will reduce New York to ashes; examining the hypothetical, experts weigh in to determine what could happen, and how it might be stopped.
Thanks for watching. Follow for more videos.
#cosmosspacescience
#howtheuniverseworks
#season11
#episode 4
#cosmology
#astronomy
#spacetime
#spacescience
#space
#nasa
#asteroid
#asteroidbelt
Thanks for watching. Follow for more videos.
#cosmosspacescience
#howtheuniverseworks
#season11
#episode 4
#cosmology
#astronomy
#spacetime
#spacescience
#space
#nasa
#asteroid
#asteroidbelt
Category
📚
LearningTranscript
00:00This show is fictitious.
00:07There is not actually an asteroid headed to New York City today,
00:11but this is based on simulations of such an event.
00:15We run simulations of fictional asteroid strike
00:18to prepare for the worst case scenario.
00:22November 4th, 2029.
00:26We face a countdown to catastrophe.
00:30A giant asteroid hurtles towards Earth.
00:35It's heading straight for the eastern seaboard of the United States.
00:43The space rock could wipe out an entire city
00:47and cause widespread devastation.
00:53Can Earth survive?
01:00New York City, November 4th, 2029.
01:16The deserted metropolis waited for the asteroid to strike.
01:24A giant space rock entered the atmosphere,
01:28heading straight for the eastern seaboard of the USA.
01:32As it comes through the atmosphere,
01:34we would see something as bright as the sun
01:37getting brighter and brighter and brighter.
01:39At speeds of maybe 20 kilometers per second or so,
01:44that's something like 18 times faster
01:46than the speed of a bullet coming out of a rifle.
01:50This asteroid was headed towards the most populous city in America.
01:56And when it impacts,
01:58it would deliver more energy
02:00than 1,000 Hiroshima nuclear bombs.
02:14It would level some of the most expensive real estate in the world
02:17in seconds.
02:19There would be a crater where Central Park used to be.
02:33I actually don't even like thinking about this.
02:37You know, of how horrible it would be.
02:39This is beyond the worst disaster
02:44the world would have ever faced.
02:45There's nothing in our history
02:47that would have done this much damage
02:49so quickly and so devastatingly.
03:01The story of the asteroid
03:03and the Earth's fight back
03:05started seven years ago
03:07here in Arizona.
03:09September 2022.
03:18The Catalina Sky Survey.
03:22Guardian of Heaven's Greg Leonard
03:24drives to Mount Lemmon Observatory
03:26near Tucson.
03:28He's on the hunt for asteroids and comets.
03:32We are the watchers of the skies for the planet.
03:36We literally represent
03:39the first line of defense
03:41against potentially incoming asteroids.
03:44And I want to emphasize
03:45the words planetary defense.
03:47This is not in the benefit
03:50for one nation.
03:51This is for the entire planet.
03:54Greg takes a series of images
03:56over a 20-minute period.
03:58Stars don't move in the photos,
04:02but asteroids and comets do.
04:06Aha.
04:10We can see four points of light
04:12tracking across the background
04:15of the stationary stars.
04:16This one is moving very quickly
04:20across the sky.
04:21So this tells me
04:22this is a real
04:24near-Earth
04:24asteroid candidate.
04:29It's one of over
04:3027,000
04:31near-Earth asteroids
04:33or NEAs for short
04:34discovered
04:35by the early 2020s.
04:40The huge gravity of Jupiter
04:42can rip space rocks
04:44from their home
04:45in the asteroid belt.
04:49Some race outwards
04:50away from the sun.
04:54NEAs head inwards,
04:56occasionally towards Earth.
04:59We didn't know it
05:01back in September of 2022,
05:03but these were our first images
05:06of a deadly incoming asteroid.
05:08It's relatively close
05:12to Earth's neighborhood.
05:14We don't know exactly
05:15how far it is yet,
05:17but it's close enough
05:18where its motion
05:19across the sky
05:20appears rapidly.
05:24The discovery of an NEA
05:26set a series of planet
05:27protection protocols
05:29in motion.
05:32Step one,
05:33enlist a global team
05:34of experts
05:35to investigate
05:36the asteroid's orbit.
05:38We had some
05:42of the brightest minds,
05:43some of the best telescopes,
05:44some of the biggest
05:45supercomputers
05:46working to protect Earth,
05:48collaborating
05:49across language barriers,
05:50across international borders
05:51to protect humanity.
05:54This International
05:56Planetary Defense Team
05:57was tasked
05:58with discovering
05:59if the distant object
06:01would become
06:02a serious threat
06:03to Earth.
06:07Their first job?
06:08Determine if the NEA's orbit
06:10would intersect
06:11with our own.
06:15Orbits are a little
06:15like roads, right?
06:17You've got a path
06:18that something follows
06:18and they can intersect.
06:20You can have a crossroads.
06:21Now, typically,
06:22if only one object is there,
06:23that's not a big deal.
06:24But if you have two objects
06:25approaching that intersection
06:26at the same time,
06:27they could collide.
06:29And that's the danger
06:30from asteroids.
06:30The team of scientists
06:35tracked the asteroid
06:36for four months.
06:39Over time,
06:40you can build up observations.
06:43You can gradually
06:44narrow down
06:45the possible number of orbits
06:47then determine
06:49whether there's any chance
06:50of a future impact.
06:53But the asteroid
06:54is orbiting the sun,
06:56the Earth
06:56is orbiting the sun,
06:57and there's this dance
06:58going on.
06:59Sometimes the asteroid
07:00is near the Earth
07:01and we can observe it,
07:03it's bright.
07:03Other times,
07:04the asteroid is on
07:05the other side of the sun,
07:06we can't observe it at all.
07:09We were lucky.
07:10The asteroid was visible
07:12throughout the fall
07:13of 2022.
07:16However,
07:17our observations
07:18of the space rock's orbit
07:20showed a very real possibility
07:23that it would slam
07:24into Earth
07:24in just seven years.
07:32Astronomers gave
07:33the incoming asteroid
07:34a suitably appropriate name,
07:37APEP.
07:39APEP was the Egyptian god
07:41of chaos.
07:43So that's a fairly good name
07:45for an asteroid
07:46that could hit the Earth
07:47because that's exactly
07:48what would happen.
07:50You would have chaos,
07:51destruction,
07:52and death.
07:53A catalog of devastation
08:03to be unleashed on Earth.
08:06But just how bad
08:07would the impact be?
08:23asteroid APEP was on a collision course
08:32with Earth.
08:34Step two in our planetary defense,
08:38know your enemy
08:38and build up a picture
08:40of the asteroid.
08:43APEP was 1,800 feet wide,
08:45five times the length
08:46of a football field.
08:47It's huge size bumps it up
08:50into a new category
08:51of asteroids.
08:54APEP was what we referred to
08:56as a PHA,
08:57a potentially hazardous asteroid.
08:58We're talking about something
09:03that is a third of a mile across.
09:04This is enormous.
09:08An 1,800 foot wide asteroid
09:10is about 112 million metric tons.
09:13That's over 300 times
09:15the weight of the Empire State Building.
09:18computer simulations of the impact
09:23of an asteroid that massive
09:25hitting a city
09:26revealed extraordinary levels
09:30of destruction.
09:31an 1,800 foot diameter asteroid
09:35that would create a crater
09:38that's three or four miles across,
09:401,600 feet deep.
09:42It would have a radiation blast wave
09:46that would set things on fire
09:49for about 20 miles,
09:51but no sooner would things
09:53be lit on fire.
09:54There would be a 500 mile an hour wind
09:58radiating out,
09:59leveling buildings,
10:00knocking down trees,
10:02destroying highways.
10:04A hundred miles away,
10:05you'd still feel
10:06a magnitude 7 earthquake.
10:09It's not easy to say
10:10what is going to kill you first.
10:12It's probably going to be
10:13simply the flash of energy.
10:15There's so much heat from this thing
10:17that you can be vaporized.
10:19If you somehow survive that,
10:21then there's going to be
10:21a blast wave that will pulverize
10:23anything in its path.
10:26To build an accurate simulation,
10:28the scientists used
10:29more than size and mass.
10:32They also studied its composition
10:34and the speed of its orbit.
10:38You need to know
10:39what an asteroid is made of,
10:41the speed of that asteroid,
10:42how large it is
10:44in order to understand
10:45will it make it through
10:47Earth's atmosphere
10:47and what might the impact effects be.
10:52Asteroids vary in composition
10:55and structure.
10:57Some are loose collections
10:59of small rocks.
11:01Others, rocky and compact.
11:06The most dangerous are metallic.
11:10A metal asteroid can be five times
11:12as dense as some of the lower density asteroids.
11:14And so for the same speeds
11:16on the same orbits,
11:18they pack way more punch
11:19when it comes to an impact.
11:24If you want to see exactly
11:26what a metallic asteroid can do,
11:28go no farther than
11:29Beringer Crater in Arizona.
11:31Now, that crater is about a mile across.
11:34And the meteor that made it
11:35was only about 150 feet across.
11:37Arizona, 50,000 years ago.
11:42The last major asteroid strike
11:44on present-day North America.
11:48A tiny, metallic space rock
11:51hits the ground
11:52at 25,000 miles an hour,
11:55releasing energy equivalent
11:57to 2.5 million tons of TNT.
12:02Scale that up to the size
12:04of 1,800-foot APEP.
12:07And it would create a blast wave
12:08the size of Delaware.
12:11If APEP were a metal asteroid,
12:13it would tear through the atmosphere
12:15like a cosmic bullet.
12:17In a modern city,
12:18without warning,
12:19it could kill a lot of people.
12:23But although they're very dangerous,
12:25they're also very rare.
12:30More common are rubble piles.
12:32Loose collections of small rocks
12:36held together by gravity.
12:46Rubble pile is kind of
12:48the perfect name for them.
12:49But you can think of them
12:50as like literally a pile of stuff
12:53out of a dump truck
12:54in your driveway.
12:55But if you take that
12:55and you put that in space,
12:57they don't have much gravity,
12:58but they have enough
12:59to stay found to each other.
13:00And that's your rubble pile asteroid.
13:02They are just barely holding on
13:05to themselves.
13:07If you were to come
13:08and just apply sufficient gravity,
13:11you could rip it apart.
13:18Pressure and heat
13:19from entering our atmosphere
13:21can also tear
13:22a rubble pile asteroid to pieces.
13:24But that can be just as dangerous
13:30to a city below.
13:34The breakup of an asteroid
13:36in the upper atmosphere
13:37is pretty devastating.
13:39It's like a nuclear weapon
13:40going off in the atmosphere.
13:41Flattening buildings
13:42and breaking windows.
13:44There are going to be
13:44mass casualties
13:45from an event like that
13:47due to just the injuries
13:48from flying glass and debris.
13:49To discover what type of asteroid
13:57APEP belonged to,
13:59the Planetary Protection Team
14:01trained their telescopes
14:02onto the space rock.
14:07Analysis revealed that APEP
14:09was a rocky,
14:10carbonaceous chondrite asteroid,
14:13or C-type for short.
14:14C-type asteroids like APEP
14:19are less dense
14:20than metal asteroids,
14:21but more solid
14:22than rubble piles.
14:24If a big enough
14:26C-type asteroid
14:27penetrates the Earth's atmosphere,
14:29it has the chance
14:30to make it all the way
14:31down to the surface.
14:32It doesn't necessarily burn up
14:34in the atmosphere.
14:35APEP's size, mass,
14:45and composition told us
14:46it would punch through
14:47our atmosphere
14:48and hit the surface.
14:54The final piece of information
14:55needed to accurately predict
14:57the true amount of damage
14:59from the impact
15:00was APEP's kinetic energy.
15:03The amount of energy
15:04the asteroid
15:05would punch into the ground.
15:09The kinetic energy
15:10of an object
15:11depends on the mass,
15:13and it depends
15:14even more strongly
15:14on the speed.
15:16More mass creates
15:18more kinetic energy,
15:19but more velocity
15:21will increase
15:22the kinetic energy
15:23by a squared factor.
15:25For example,
15:26if something has
15:27twice the velocity,
15:28it will have
15:29four times
15:30the same energy.
15:32Scientists calculated
15:34how much energy
15:35APEP weighing in
15:37at 123 million tons
15:39and traveling
15:40at 40,000 miles an hour
15:42would transfer
15:43into the Earth.
15:45So what kind of energies
15:47were involved here?
15:481,800-foot diameter asteroid,
15:51it's 112 million tons
15:53and is traveling
15:53at 40,000 miles per hour.
15:56That's something
15:56on the order of
15:5710 to the 19th joules
15:59of energy,
16:00a one followed
16:00by 19 zeros.
16:101.8 times 10 to the 19 joules
16:12is equivalent
16:13to 5,000 megatons.
16:16Take a one megaton nuke,
16:18a substantial nuclear weapon,
16:20and then blow up
16:215,000 of them.
16:23That is roughly
16:25the same amount
16:26as all the nuclear weapons
16:27on Earth
16:28detonating all at once.
16:35A strike this large
16:36would affect
16:37the whole planet.
16:40This would have
16:41global impacts.
16:43We would have to deal
16:44with the fallout,
16:44the literal fallout
16:45from this event
16:46for potentially
16:481,000 years.
16:49Spring, 2023.
16:56We had two choices.
16:58Do nothing
16:59and face a planet
17:00changing catastrophe
17:01or fight back.
17:04We chose
17:05to take on APEP.
17:08It was
17:09the first time
17:10in human history
17:11that we might
17:12actually be able
17:13to prevent
17:14a natural disaster
17:15from happening.
17:16We could plan
17:17and launch
17:18a response mission
17:20so we don't have
17:21to get out of the way.
17:22Make it get out
17:23of the way instead.
17:26The mission's objective
17:28was simple.
17:30Stop the asteroid
17:31and save the world.
17:35We can't superglue
17:37an earthquake fault shut.
17:38We can't cork volcanoes.
17:41But planning
17:42for an asteroid impact
17:43is something
17:45we really could do.
17:48June, 2023.
17:59A large asteroid
18:00was headed
18:01towards Earth.
18:04It was predicted
18:05to strike
18:06on November 4th,
18:082029.
18:09To protect our planet,
18:18a team of scientists
18:19planned to deflect
18:20the asteroid.
18:25An 1,800-foot-wide asteroid
18:27was headed
18:28towards the Earth.
18:29We needed it
18:30to go in
18:31literally
18:32any other direction.
18:34So how could we
18:35push APEP
18:36off course?
18:37scientists found
18:42a clue
18:42in the asteroid belt.
18:48Sometimes,
18:49the lumps
18:49of space debris
18:50collide
18:51and change
18:52their trajectory.
18:54Maybe we could
18:56replicate this
18:56and deflect APEP.
19:00We could try
19:00to deflect the asteroid
19:01and change its orbit
19:02so that it actually
19:03misses the Earth.
19:03If you do it
19:05early enough,
19:06it may not be much,
19:07less than half
19:09a millimeter
19:09per second.
19:10But that is enough.
19:13These asteroids
19:13travel for millions
19:15of miles.
19:17And so over the course
19:18of days,
19:19weeks,
19:20months,
19:20and years,
19:21it will have
19:21a radically
19:22different orbit.
19:25Sounds simple.
19:26Send up a rocket
19:27with a robotic
19:28space probe,
19:30travel millions
19:31of miles,
19:32and knock APEP
19:33away from Earth.
19:35Piece of cake.
19:38In the movies,
19:40when there's
19:40a threatening asteroid
19:41that's found,
19:42there's always a rocket
19:43on the pad
19:44ready to go
19:45after that.
19:46And it's not the case
19:47in real life.
19:48It takes years
19:50to design the mission,
19:51to build the satellite,
19:52to launch it,
19:53and then it has
19:54to get there,
19:55and that might be
19:56millions of miles
19:57away from Earth.
19:59Fortunately,
20:00Earth had a head start.
20:02We detected APEP early.
20:07And we'd already
20:08built an asteroid
20:10deflector,
20:11called the Double
20:12Asteroid Redirection
20:14Test,
20:15or DART
20:16for short.
20:19In 2021,
20:21we sent DART
20:226.8 million miles
20:24to rendezvous
20:25with an asteroid
20:26called Didymos.
20:29Didymos posed
20:30no threat to Earth,
20:31but allowed us
20:32to test the technology.
20:35The asteroid
20:36called Didymos
20:37has a small moon asteroid
20:39going around it.
20:40The point of the DART
20:41mission was to send
20:42an impactor
20:43into this little moon
20:44and see how much
20:45we nudge it
20:46off the orbit
20:46that it's in.
20:49Lessons learned
20:50from DART
20:51would inspire
20:52a new mission.
20:56November, 2025.
20:58We launched
21:00the DAF mission,
21:01deflect APEP
21:02away from Earth.
21:06This wasn't a test run
21:07to a safe asteroid.
21:09This was the real deal,
21:11a mission
21:11to save our planet.
21:14It was an enormous
21:15technical challenge,
21:16and we had
21:18no idea
21:18if it would work.
21:21When you think
21:22about a spacecraft
21:23going from Earth
21:25millions of miles
21:26away to hit
21:27an asteroid
21:28at an exact
21:29point in time,
21:30at an exact point
21:30in space,
21:31it's really
21:31the ultimate bullseye.
21:33It's like
21:34trying to hit
21:35one bullet
21:36with another bullet
21:37launched from
21:38the other side
21:38of a continent.
21:41November,
21:422028.
21:43after three years
21:46in space,
21:47DAF
21:48arrived
21:49at APEP.
21:52This was our
21:53last chance.
21:54This was our
21:55only chance.
21:58The kinetic impactor
22:00smashed into APEP
22:02at 14,000 miles
22:03an hour.
22:04On Earth,
22:11telescopes and radar
22:13tracked the collision.
22:16Did it work?
22:17Did we push
22:17the asteroid
22:18off course?
22:20At first glance,
22:21the mission worked.
22:22We deflected
22:24APEP away from us.
22:27It looked like
22:28the mission worked.
22:32As an astronomer,
22:34and, you know,
22:35a human who has
22:35to live on this planet,
22:37I was very happy, right?
22:38We've just literally
22:39saved the world.
22:41But the happiness
22:42was short-lived.
22:44There was a problem.
22:46The collision
22:47had pushed APEP
22:48away from Earth.
22:53But it also
22:54sheared off
22:55a 300-foot chunk
22:57of rock.
22:59This smaller asteroid,
23:01called APEP 2.0,
23:03could still be
23:04a significant threat.
23:08A 300-foot chunk
23:09of rock
23:09is still very,
23:10very large.
23:13300 feet wide.
23:15That's almost
23:15a football field.
23:18So the important things
23:19we need to know,
23:20was it going to hit us?
23:22And if so,
23:23where is it going to hit us?
23:25March 2029,
23:29we got our answer.
23:31Its point of impact,
23:33the east coast
23:34of the United States,
23:36with New York City
23:38in the firing line.
23:43Smaller chunk
23:44headed for New York City.
23:47This was the worst
23:48case scenario.
23:50I want to emphasize,
24:00there's no asteroid
24:01headed toward New York
24:02tonight.
24:02This is just a discussion
24:04about what this process
24:06would be like.
24:07In 2028,
24:17we tried to deflect
24:18APEP away from Earth.
24:22The mission
24:23wasn't a complete success.
24:27Yes,
24:27we managed to actually
24:28divert the large asteroid
24:30away from hitting the Earth.
24:31But in doing so,
24:33we broke off a clump
24:34big enough
24:34to be very dangerous
24:35heading toward
24:36the eastern seaboard.
24:39June,
24:402029.
24:42Five months to impact.
24:46The future looked bleak
24:47for New York,
24:48but it wasn't the time
24:50to give up.
24:52They reassessed
24:53an idea
24:53first suggested
24:55to destroy
24:55the original
24:561,800-foot APEP,
24:58a nuclear strike.
25:03It worked in Armageddon.
25:05Maybe it would work
25:06in real life.
25:08However,
25:09studies revealed
25:10that nuking an asteroid
25:12wasn't as simple
25:13as it looks
25:14in a Hollywood movie.
25:16Hey, let's blow it up.
25:17Let's nuke it, right?
25:19Well,
25:19instead of one big problem,
25:21now you have
25:21slightly smaller problems.
25:23And they're radioactive,
25:24by the way.
25:25So you don't want
25:25to do that.
25:28Computer simulations
25:29revealed
25:30that even the world's
25:31largest nuclear weapon
25:33had only
25:341% of the energy
25:36needed
25:36to destroy
25:37the original
25:381,800-foot APEP.
25:42We needed
25:43the world's
25:44most powerful
25:44nuclear weapon,
25:45and 99 of its
25:47best friends
25:48launched them
25:49all simultaneously
25:51and have them
25:51simultaneously
25:52hit the asteroid.
25:54It was simply
25:55beyond our
25:56technological capabilities.
26:00Fortunately,
26:01thanks to the
26:02DAF mission,
26:02we only had to
26:03take out the
26:04300-foot
26:05APEP 2.0.
26:12Could we blow
26:13this smaller
26:13asteroid
26:14out of the sky?
26:19Maybe,
26:20but launching
26:20a nuclear
26:21Hail Mary
26:22would be
26:23very controversial.
26:26Nuclear devices
26:27are
26:28the most
26:29powerful,
26:31really,
26:31one of the most
26:32emotional things
26:33that humans
26:34have ever
26:35invented.
26:39They are
26:40the most
26:41powerful tool
26:42in our toolbox.
26:43We've got a
26:44hammer,
26:44and it's a
26:44very big
26:45hammer.
26:46But there
26:47are a lot
26:48of concerns
26:49with them,
26:50so they
26:51cannot be
26:52tested in
26:53space,
26:53according to
26:54international
26:54law.
26:56Without being
26:57able to test
26:58nukes in
26:59space,
26:59they were
27:00considered
27:00too big a
27:01risk.
27:05But New York
27:07had one
27:07final
27:08potential
27:09savior,
27:10the Earth
27:12itself.
27:172013,
27:18Chelyabinsk,
27:19Russia.
27:21An asteroid
27:22blew up
27:23in the
27:23atmosphere.
27:24It didn't
27:27make it
27:27all the
27:28way to
27:28the surface,
27:28and the
27:29people in
27:29Chelyabinsk
27:30are very
27:30lucky because
27:31of that.
27:32The 60-foot
27:34wide Chelyabinsk
27:35asteroid was
27:36rocky, like
27:37APEP, and
27:39it moved at a
27:40similar velocity,
27:41around 40,000
27:42miles an hour.
27:43But it
27:45met its
27:45match when
27:46it entered
27:47Earth's
27:47atmosphere.
27:50Earth's
27:51atmosphere
27:51doesn't look
27:52like much.
27:53You think,
27:53oh, it's
27:53just air,
27:54it doesn't
27:54matter, but
27:55all of those
27:55molecules actually
27:56exert pressure
27:57on the front
27:58edge of the
27:58asteroid,
27:59slowing it
27:59down and
28:00heating it
28:00up.
28:02The rock
28:03heated up
28:03and began to
28:04crumble and
28:05explode as it
28:06came through.
28:07The mid-air
28:08explosion,
28:09called an
28:10airburst,
28:11released more
28:11energy than
28:12440,000 tons
28:14of TNT.
28:21The shockwave
28:22traveled 100
28:23miles,
28:25damaging 7,000
28:26buildings and
28:27injuring 1,500
28:28people.
28:30But a ground
28:31strike hitting
28:32a city would
28:33have been a lot
28:34worse.
28:41APEP
28:422.0 was
28:43five times
28:44larger than
28:45the Chelyabintz
28:46grok.
28:48Would it
28:49break up
28:50during its
28:5010-second
28:51trip down
28:52through the
28:52atmosphere?
28:53Or would it
28:54pierce right
28:55through?
28:58The planetary
28:59defense team
29:00ran simulations.
29:01As that
29:04comes through
29:05Earth's
29:06atmosphere,
29:07some of that
29:07hot air can
29:08get into
29:08the cracks.
29:11Friction and
29:12pressure would
29:13heat APEP
29:142.0's surface
29:15to thousands
29:16of degrees
29:17Fahrenheit.
29:19At those
29:19temperatures,
29:20even rock
29:21burns.
29:23We would see
29:24this flaming
29:25monster of
29:27death coming
29:28racing through
29:29our atmosphere.
29:30air.
29:31There were
29:31going to be
29:32pieces of
29:32debris vaporizing
29:34and coming
29:34off of it.
29:35So you get
29:36these flashes
29:37of light that
29:37happen one
29:38after them.
29:38Pop, pop, pop,
29:39pop, pop, pop,
29:39pop, as these
29:40things are blowing
29:40up.
29:46The computer
29:47simulations
29:48showed that the
29:49extra bulk of
29:50APEP 2.0 would
29:52stop it from
29:53blowing up.
29:53Some of the
29:57asteroid would
29:58blast away, but
30:00most of the
30:00space rock would
30:02reach the
30:03Earth's surface.
30:05So that close
30:07to the actual
30:07impact, we
30:08pretty much just
30:09had to hunker
30:09down and take
30:10it.
30:13The prospects
30:14for New York
30:15City were grim.
30:16It was facing
30:19annihilation.
30:32October,
30:342029.
30:35Three weeks
30:36to impact.
30:37For the
30:40citizens of the
30:41New York
30:41metropolitan area,
30:42there was only
30:44one goal.
30:46Get out of the
30:47firing line.
30:52Now we had to
30:53have the plans in
30:54place to evacuate
30:55these cities.
30:57It was a major
30:58emergency for New
30:59York and its
31:00citizens.
31:01Time to move
31:03out of the way.
31:05To work out
31:06who should
31:07evacuate and
31:08to where,
31:09scientists ran
31:09detailed projections
31:10of the potential
31:11blast area.
31:14There's an
31:15ellipse there that
31:16we call the
31:16hazard ellipse that
31:17says somewhere in
31:19this area is where
31:20the asteroid will
31:21hit.
31:22That means there's
31:22a little wiggle
31:23room and a range
31:24of areas that are
31:25in danger.
31:28Based on the
31:29hazard ellipse
31:29projections, the
31:31government issued
31:32evacuation orders for
31:34the tri-state
31:35area.
31:36and as far
31:37south as
31:38Philadelphia, it
31:40was the biggest
31:41evacuation in U.S.
31:43history.
31:45Millions were
31:46displaced.
31:47It was physically
31:48horrific.
31:51I live in the New
31:52York metropolitan area.
31:54It was horrible for me
31:55and my family and my
31:56friends.
31:57But we can't just sit
31:59here and cross our
32:01fingers and hope that we
32:02don't get struck.
32:04The freeways out of the
32:06city were jammed.
32:12Trains were packed.
32:14Over 23 million people
32:16evacuated, leaving behind
32:19a deserted city.
32:20computer models showed that
32:25the epicenter of the
32:26strike would be
32:27Manhattan.
32:31The blast would reduce
32:32the city to rubble and
32:34ash.
32:36There would be a one-mile
32:38wide crater resulting from
32:39it, so deep that it would
32:41actually take the entire
32:42subway system and turn it
32:43upside down and lay it onto
32:45the rim of the crater.
32:46You would have a magnitude
32:49five earthquake at even six
32:51miles away from that, and
32:53there would be a big air
32:54blast, 400-mile-an-hour
32:56winds.
32:58Something as light as a
32:59pencil could be a lethal
33:00weapon when picked up by a
33:01shockwave like that.
33:03As the crater is blasting
33:06out and excavating itself,
33:08there would be little blobs of
33:11molten rock that get thrown
33:13out in this wave going faster
33:15than the speed of sound.
33:18Like drops of fiery rain,
33:20if you will, landing back
33:21miles away from the crater.
33:27The city would be on fire.
33:32So there's just no upside to
33:35this.
33:36There's nothing good.
33:36It's just all from bad to
33:38horrific.
33:40But New York is by the ocean.
33:42What would happen if APEP 2.0
33:46hit the sea?
33:52Detailed simulations have
33:54revealed two very different
33:56outcomes for an asteroid
33:58hitting the ocean at high
34:00speeds.
34:01If a giant asteroid strikes the
34:07deep ocean, less than 1% of its
34:09energy gets converted into waves.
34:11Those waves quickly disperse.
34:14They quickly lose energy as they
34:16travel.
34:16By the time they reach the coast,
34:19it might just be a little ripple.
34:21You might not even be able to
34:23surf on it.
34:24If the asteroid hits shallow
34:31coastal waters,
34:33it could cause significant damage
34:37along the shoreline.
34:39If an asteroid the size of APEP
34:42hits the continental shelf where
34:43the water is relatively shallow,
34:45then it could potentially cause a
34:48tsunami.
34:48But that would just be the start
34:54of the problems.
34:58With a shallow water impactor,
35:00huge amounts of steam are
35:02generated basically by the energy
35:04of that impactor vaporizing all
35:06the water.
35:07Well, all the water is then put up
35:08into the atmosphere and water is
35:10a really good greenhouse gas.
35:12So you have warming from the launch
35:14of water up into the atmosphere.
35:15You have cooling from all of the
35:17ash and dust.
35:18A short bout of warming would be
35:26followed by a brutal winter.
35:29Crops would fail.
35:32This impact has so many horrible
35:35follow-on consequences that tells
35:38us how difficult it would be to
35:41rebuild from an event like this.
35:48The eastern seaboard would suffer a
35:50serious economic downturn.
35:52It would take decades to recover.
35:59November 3rd, 2029.
36:02One day until impact.
36:04The space rock was just 400,000 miles away
36:09and traveling 13 times faster than an F-15
36:14fighter jet.
36:15It was first a dim star and then a brighter star.
36:20And then in the hours before, you could actually see it
36:23approaching the Earth approaching the Earth.
36:24New York looked outmatched.
36:28It looked like APEP would win.
36:31But this was not the end of the game.
36:34Earth had one final card to play.
36:37November 4th, 2029.
36:52The 300-foot APEP 2.0 reached Earth.
36:57The space rock pierced our atmosphere
37:02and hurtled towards the surface.
37:17Then, the asteroid passed over Manhattan.
37:22It hit deep ocean, 350 miles off the coast.
37:42APEP 2.0 missed New York.
37:46But how?
37:46Our seven-year battle with the asteroid
37:52resolved in a matter of seconds.
37:55Thanks to orbital dynamics.
37:59The orbit of the asteroid and the orbit of the Earth
38:01and the way the Earth spins in this great cosmic ballet
38:05means that a few seconds earlier or later
38:08makes the difference between hitting the ocean
38:11and hitting land.
38:14Earth rotates at 1,000 miles an hour.
38:17And orbits the sun at close to 65,000 miles an hour.
38:23APEP orbited at 40,000 miles an hour.
38:27But APEP 2.0 traveled fractionally slower.
38:33The impact of the DAF mission
38:35that sheared off the 300-foot chunk of rock
38:38had also slowed it down.
38:41Slowing down APEP changed when it's going to intersect the Earth.
38:45So New York spun out of the crosshairs.
38:51APEP 2.0 hit the ocean and exploded,
38:56breaking up instantly.
38:57The strike threw up a wall of water into the air,
39:03followed by huge clouds of steam.
39:07The impact created small surface waves that quickly died away.
39:12It's like doing a gigantic interplanetary belly flop.
39:17It evaporates, it obliterates, and it generates an enormous amount of steam,
39:22and it sets up shockwaves.
39:24All that energy is still released, but the ocean is capable of absorbing it.
39:28New York dodged a bullet and escaped unscathed,
39:36thanks to the dedication, ingenuity,
39:40and enterprise of a global team of scientists.
39:44APEP was an imaginary asteroid.
39:54But there are many potentially hazardous space rocks out there.
39:59Thankfully, this was a fictional scenario.
40:04It's a thought exercise.
40:05But it's informed by our real, actual knowledge we've gained over the years
40:10of dealing with, you know, potential close approaches
40:12and the hazard from real asteroids that we actually know about.
40:18Asteroid research is a good insurance policy for our species.
40:23Hopefully, we will never need to carry these things out for real.
40:28Large asteroid strikes are rare.
40:31But we cannot be complacent.
40:38The most important thing to do in planetary defense is to find them early.
40:44If we find them early, we have a chance to predict the possible impacts,
40:47and we have a chance to mitigate them.
40:54Our technology is improving.
40:58So we can detect incoming space rocks earlier.
41:03But we need to be vigilant,
41:06because the threat from asteroids is not going away.
41:12Apart from climate change,
41:13asteroid strikes are, in my opinion,
41:16the most dangerous thing to life on Earth.
41:19A lot of the times the question I get is,
41:21what are the chances of this happening?
41:24And they don't like the answer, because I say 100%.
41:28It takes time.
41:29It may not be for a week, a month, a year, a century.
41:33But studying these asteroids informs us on what we can do to prevent an impact.
41:38There are a lot of natural disasters that we can do nothing about.
41:42Earthquakes, hurricanes, that sort of thing.
41:44Here is something way more devastating than any of those,
41:47and we can prevent them.
41:50So, we have to keep our eyes on the prize and our eyes on the skies.
41:54We are so close.
41:56And if you'd like the