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00:00The blueprint of the universe is drawn with magnetic lines.
00:09Magnetic fields help stars ignite.
00:14They shape entire galaxies.
00:18And the same force that creates magnetism is the cement that holds all matter together.
00:26Without this universal glue, there would be no stars, no planets, no people, and no light.
00:57December the 27th, 2004.
01:00While America slept, an immense shockwave rippled through space.
01:06The invisible wave had been traveling at the speed of light for 50,000 years.
01:13It shook the Earth's protective magnetic field,
01:18ripped out a chunk of our upper atmosphere, and blinded several satellites.
01:23It was one of the most tremendous events ever seen in modern astrophysics.
01:29The blast of energy was huge,
01:32but the Earth's protective magnetic field did just enough to prevent serious damage.
01:40Even so, scientists were rattled.
01:43They searched for the culprit.
01:46Was it a giant supernova?
01:50Was it the jet from a massive black hole?
01:54But the usual suspects weren't to blame.
01:57This was something new.
02:00The source was found on the other side of the galaxy,
02:04a tiny star with a magnetic field stronger than anything scientists had ever seen before.
02:10From 50,000 light years away,
02:13this little object just a few miles across had such a hissy fit
02:17that it physically affected the Earth.
02:22Fortunately, this magnetic death star was far away.
02:27Even so, science had woken up to the terrifying power of magnetism.
02:35Magnets appear to be simple.
02:37They either stick together or push apart.
02:43You're probably familiar with playing around with magnets,
02:45and you get them close together,
02:46and it's almost like they reach out and grab each other and pull each other together.
02:50But if you flip them around, they repel.
02:53A magnet can attract and repel.
02:56This remarkable feat relies on the two magnets swapping packets of energy
03:01that physicists refer to as particles.
03:04It turns out that what's going on is that there are particles
03:07that are being exchanged between this magnet and this magnet,
03:11and those particles are called photons.
03:13These are the same photons that create light.
03:19Photons are the packets of energy that our eyes detect to see the world around us.
03:25Plunging down to the subatomic level reveals how photons are at the very heart of magnetism.
03:32This bizarre world is ruled by the laws of quantum mechanics
03:36and inhabited by tiny objects such as atoms,
03:39each a nucleus surrounded by a cloud of electrons.
03:43Think about the structure of an atom.
03:45There's a positive charge to the nucleus,
03:47and then the electrons have a negative charge.
03:49These two attract each other.
03:53To explain this force,
03:55physicists think that both the nucleus and the electrons spit out short-lived bursts of photons.
04:05The oppositely charged particles absorb each other's light,
04:09and this draws them together.
04:13The force is known as electromagnetism.
04:18Atoms themselves would not hold together if it weren't for electromagnetic forces.
04:24Electromagnetism also sticks atoms together to form molecules.
04:30And it sticks the molecules together to make us and everything around us.
04:35Electromagnetism is responsible for the very structure of our matter,
04:39atoms holding together.
04:44Molecular bonds in our bodies, those are bound together by electromagnetic interactions,
04:49and therefore they're bound together by light.
04:54A universe without electromagnetism would come apart at the seams.
05:00If electromagnetism was turned off, matter would dissolve.
05:08Everything would just fall apart.
05:13I could probably, with my superhuman strength, hold myself together, but the rest of you are doomed.
05:32Without electromagnetism, nothing would be solid.
05:41When you touch something, that's the electromagnetic force as well.
05:45We have electrons in our atoms, and they repel each other,
05:48and when you try to touch something, those forces keep you from actually physically touching it.
05:55The reason I don't fall through the floor is not that the floor is particularly solid.
05:59Most of the floor is empty space.
06:01It's the electric forces of the atoms in the floor
06:04against the electric forces of the atoms in my body that hold me up.
06:09Those little forces of those few atoms are enough to hold me up
06:13against the entire gravitational force of the Earth.
06:18Electromagnetism rules.
06:23The electromagnetic force is far stronger than gravity,
06:27and now scientists are beginning to understand its power on a cosmic scale.
06:35Turn back the clock to when the universe was just 380,000 years old.
06:44There were no stars or planets,
06:47just a broiling, dense soup of excited protons and electrons
06:52hurtling through a sea of high-energy photons.
06:57In the early universe, there were no atoms because the energy was so intense
07:00that separate charged particles existed in a very hot, dense, primordial soup.
07:05Then, as the universe cooled, everything changed.
07:09Between the time the universe was about a minute old
07:12and the time when the universe was 300,000 years old,
07:15electromagnetism slowly came to the fore,
07:18and protons and electrons began to feel electric forces and combine as atoms.
07:24Electromagnetism essentially began to determine the dynamics of matter
07:29and the ultimate formation of everything we see.
07:35Now electromagnetism could flex its muscles.
07:39It pulled electrons and protons together to form hydrogen, the first atom.
07:47The hydrogen atoms bunched together to form clouds of hot gas.
07:52These newly formed clouds glowed, and the lights of the universe were turned on.
08:06As the newly formed atoms swirled around each other,
08:10their combined magnetic effect grew stronger.
08:15These smallest magnets in the universe are atoms themselves
08:18that create basically mini-barb magnets that are on the scale of the subatomic world.
08:25The hydrogen micromagnets began to align,
08:28generating vast highways of strong magnetic fields.
08:35And then over time, what happens is that these magnetic fields begin to grow,
08:39and so all the magnetic fields we see today in our universe
08:42can really be attributed to these primordial magnetic fields.
08:46Electromagnetism shaped the early universe, but it didn't stop there.
08:53It went on to help with the next milestone in the universe's evolution, the stars.
08:58The old picture of how stars are formed is all you need is gravity and time.
09:02But we've come to understand that the problem is a little trickier than that,
09:05that actually magnetic fields play a fundamental role.
09:09So it's possible that without these magnetic fields, stars themselves would not exist.
09:17A billion years after the Big Bang,
09:20magnetism injects life into the universe's first ever stars.
09:39Astronomers once believed that star formation was simple.
09:44A vast cloud of interstellar gas drawn together by its own gravity.
09:51Temperatures and pressures rise as the gas compresses,
09:56until it's hot enough and dense enough for nuclear fusion to ignite the core,
10:03and a star is born.
10:07At least that's what the scientists used to think,
10:10but recently they discovered a problem with this simple theory.
10:16The primary mover when you're forming a star is gravity.
10:20The material condenses in the centre to form a star,
10:23and as that star forms, there's material swirling around it,
10:26attracted to that central mass by its gravity.
10:29But there's a problem. This stuff has what's called angular momentum.
10:34Angular momentum stops the moon from falling into the earth.
10:38Scientists realised that this same force would stop the gas from falling into the forming star,
10:45so the star would never reach critical mass and never ignite.
10:50Angular momentum and gravity are basically in a fight.
10:53The angular momentum is what keeps things spinning around out here,
10:56whereas the gravity wants to tug it in towards the middle.
10:59If somehow we could lose that angular momentum, then star formation would progress.
11:04Before a star can be born, it needs to draw in enough gas
11:08to boost the temperature in its core to 15 million degrees Celsius.
11:16Scientists realised that for that to happen,
11:19something would have to break the deadlock between gravity and angular momentum.
11:25That's where magnetism can play a role.
11:27The magnetism of the protostar, the forming star,
11:30can actually affect the disk and slow it down
11:33and actually let it drop in and help the star itself form.
11:39When charged particles move, they produce magnetic fields.
11:44In this case, the swirling gas and the spinning star
11:48generate magnetic fields that are powerful enough to slow the gas cloud down.
11:53Magnetism works like a cosmic brake.
11:56It slows down a little bit and eventually spirals into the centre.
11:59Gravity starts to win. Gravity beats out that angular momentum and star formation happens.
12:07Finally, slowed by the magnetic field, gravity drags the gas ever closer,
12:13crushing it and heating it until...
12:19...ignition.
12:21A star is born.
12:2412 billion years ago, the first stars burst into life.
12:32Without magnetism, we'd still be in the dark.
12:40But magnetism can also bring terrible destruction.
12:44And some of these early stars are destined to transform into magnetic monsters.
12:54The transformation begins when the star runs out of fuel.
12:59A sudden and violent reaction takes place.
13:04It implodes.
13:06This is known as a supernova.
13:12The star's outer layers are blown out into space.
13:17What's left behind, including the magnetic field, is crushed by gravity.
13:24If you look at stars, just about all stars have strong magnetic fields at their surface.
13:29What happens is that if a star dies and it collapses,
13:33the same amount of magnetic field must still be present.
13:36So if the surface area of the star is decreased by a factor of 1,000 or 10,000,
13:41then that means that the magnetic field intensity must increase by that same amount.
13:48What's left is an ultra-dense, ultra-magnetic ball,
13:52roughly the size of a city.
13:57These objects are more than a trillion times denser than lead,
14:01and they have the potential to harbor the most extreme magnetic fields ever seen.
14:06They are called magnetars.
14:09These dense balls have very, very strong magnetic fields,
14:12in fact, the strongest magnetic fields in the universe.
14:17The magnetic field can be more than a trillion times stronger than the Earth's field.
14:25If you got very, very close to a magnetar,
14:28that strong magnetic field might possibly rip you apart,
14:32because your atoms just can't stay together in the vicinity of such a strong magnetic field.
14:39Scientists know of 23 magnetars in the Milky Way,
14:43but they think there could be many more.
14:48One, SGR 180620,
14:52located 50,000 light-years away on the other side of the galaxy,
14:56was the same magnetic monster that unleashed an assault on the Earth in 2004.
15:10The electromagnetic shockwave was triggered by a starquake.
15:17That's like an earthquake, but it's on a star,
15:20and the crust of the star slipped about this much,
15:23literally about a centimeter, the width of your finger.
15:26But this was far larger than any earthquake this planet has ever seen,
15:30millions of times stronger.
15:32And the magnetic field is coupled with the matter in it,
15:35so when the crust slipped, so did the magnetic field.
15:38And it launched a blast of energy so powerful
15:42that 50,000 light-years away, it physically affected our planet.
15:55This tiny slip had a colossal effect.
16:02If this thing had been a lot closer, the effect on us would have been huge.
16:09If a magnetar erupted a couple of light-years from Earth,
16:13it could devastate our planet.
16:17There could be a burst of radiation that could literally strip away our atmosphere.
16:22A blast from a magnetar could blow our atmosphere into space,
16:26leaving the planet's animals gasping for air.
16:30In this near vacuum, our oceans would quickly boil away,
16:34and Earth would become a lifeless ball of rock spinning through space.
16:39In the cosmic menagerie of beasts and ghouls and things that go bump in the night,
16:43I think magnetars are at the very top of the list of things that really are pretty scary.
16:53Magnetars have alerted scientists to the incredible power of electromagnetism.
16:59And yet, for many years,
17:01scientists believed it was a minor player in the evolution of our galaxy.
17:07But new data has revealed a magnetic field on a cosmic scale.
17:19For centuries, mankind has been studying the night sky,
17:24mapping out the gas, dust and stars.
17:30But we've missed a structure as big as the galaxy itself.
17:39A vast magnetic field that measures more than a quintillion kilometers across.
17:46A single atom can have a magnetic field.
17:48A bar magnet can have a magnetic field.
17:50Our planet does. The sun does.
17:52And in fact, structures even as large as galaxies can.
17:59The galactic magnetic field is huge.
18:01It's basically the size of the entire Milky Way.
18:08The field is far stronger than anyone had realized.
18:12If you add up the magnetic fields from the stars and the gas that fill our galaxy,
18:20it still can't account for all the magnetism we see.
18:27Something else is powering it.
18:31But what?
18:33Something else is powering it.
18:37But what?
18:42Where do all of these big magnetic fields come from?
18:45Where are the magnetic fields coming from that are pervading the galaxy?
18:51Scientists got the first clue to the origin of these mysterious magnetic fields
18:56by looking at the remains of dead stars.
19:03Cassiopeia A
19:10Records suggest that Cassiopeia A suffered a cataclysmic supernova explosion
19:15around 300 years ago.
19:21What remains is a vast ball of gas and dust
19:25hurled out into space by the exploding star.
19:29As the gas expands outwards in the shape of a giant bubble,
19:33it crashes into neighbouring clouds of interstellar gas.
19:38Astronomers have discovered that these collisions generate strong magnetic fields.
19:44And the extra magnetism contributes to the larger galactic magnetic field.
19:49The question is, by how much?
19:53A new breed of experimental cosmologists are determined to find out.
19:59Jenna Meiniker is using one of the world's most powerful lasers
20:03to simulate supernova shockwaves in the lab.
20:11What I can do is use large lasers, in fact the largest lasers on Earth,
20:15to create supernovas which can fit in the palm of your hands.
20:21Jenna starts the experiment by placing a small piece of carbon rod
20:25into the laser target area.
20:28We put all six laser beams onto this carbon rod target
20:32in a gas-filled chamber.
20:34And so what happens is that this material will expand out ballistically,
20:37creating a shockwave.
20:39And what we hope is that this shockwave will generate magnetic fields.
20:44Alright, locking down for a shot.
20:48Everyone evacuate.
20:54Hi, this is Bay, this is target area west.
20:56Locked down, ready for a shot.
20:58Full energy on all six beams.
21:04The laser operations team focuses on the tiny carbon target.
21:09The laser heats the target to over a million degrees.
21:16The carbon explodes, creating a shockwave that slams into the surrounding gas.
21:22Success. Got our shot.
21:27So it looks like our laser hit the target quite well.
21:31We have this beautiful shockwave here that's being emitted.
21:34So the laser came in this way, hit our carbon rod.
21:37This is all the sort of debris that was moving out quite fast.
21:41And then this is the shockwave which generated as a result.
21:46Instruments detected strong magnetic fields along the line of the shockwave
21:51as it struck the gas around it.
21:54So this shockwave is moving out into space
21:56and this is what's creating all these magnetic fields along this front.
22:03Jenna thinks a similar process creates vast magnetic fields in space.
22:12Supernova shockwaves slam into gigantic interstellar gas clouds like a tsunami,
22:17raising a fast-moving front of turbulent gas.
22:24Charged particles inside the gas cloud tumble over and over each other,
22:30generating powerful magnetic fields that extend far out into space.
22:38So what you have is a mixing of charged particles
22:40that are now spinning around and moving fast.
22:43So what you have is a mixing of charged particles
22:45that are now spinning around and moving fast in chaotic ways.
22:48Whenever you have that kind of activity, you have magnetic fields.
22:52It seems that powerful magnetic fields break out
22:55whenever clouds of interstellar gas collide.
22:58This phenomenon is not just limited to supernova explosions,
23:03because they aren't the only cosmic phenomena with the power to shock.
23:08Overfed black holes blast jets of superheated matter into space.
23:14These jets pierce through gas clouds,
23:17producing turbulence and powerful magnetic fields.
23:24And sometimes drifting clouds of interstellar gas smash into each other,
23:30creating huge magnetic storms.
23:33Collisions like these are the steroids that boost the Milky Way's magnetic muscle.
23:40And the distribution of this magnetic bulk
23:43may be the key to unlocking one of the greatest mysteries in cosmology.
23:48Why our galaxy is missing over a trillion stars.
24:04The Milky Way is made up of more than 200 billion stars.
24:09And yet for astronomers, even this astronomical figure isn't enough.
24:15That's because surrounding our galaxy is a vast halo of gas,
24:19the perfect star fuel.
24:21According to calculations,
24:23it should have turned into thousands of billions of new stars.
24:27But it hasn't.
24:29One of the things that's hard to understand about the Milky Way
24:31is why there are actually so few stars.
24:33Our Milky Way should have ten times as many stars as it does,
24:36but it doesn't.
24:37One of the big questions is why.
24:45According to the rules of old-fashioned physics,
24:48the colossal clouds surrounding the Milky Way
24:50should have been sucked inside the galaxy's boundaries.
24:55Here, the gas would have condensed under its own gravity
24:59and formed into new stars.
25:06But cosmologists now think
25:08that magnetic fields are holding the gas back.
25:12And that's why the Milky Way is so small.
25:16It's not even close.
25:19But cosmologists now think
25:21that magnetic fields are holding the gas back.
25:24There's a huge amount of gas
25:26that comes way from outside the galaxy
25:28that wants to fall in and then be available for star formation.
25:31What prevents all of that gas and dust
25:33that we know is out there from turning into stars?
25:36It might just be magnetic fields.
25:42Magnetism now plays a key role
25:45in our understanding of how galaxies form.
25:50Ten billion years ago,
25:52the fledgling Milky Way was nothing more than a vast ball of stars.
25:59But over time,
26:01spin flattened the ball into a disk.
26:06The disk grew
26:08as gravity sucked in more and more stars.
26:12Gravity is ultimately first responsible
26:15for the collapse of matter, which form galaxies.
26:18Once matter begins to move and interact,
26:23magnetic fields become important.
26:28Early supernova shockwaves created turbulence,
26:31spreading magnetic fields through the infant Milky Way disk.
26:35As the disk spun,
26:37these magnetic lines wove a protective cloak
26:40around a young galaxy.
26:45Here's the problem.
26:47In our galaxy, it's such a tangled web of magnetic field lines,
26:50and this magnetism can prevent stuff
26:52from falling in on the center of the galaxy.
26:56This powerful magnetic web
26:58stopped the vast reserves of gas from forming.
27:01Magnetic fields played a fundamental role
27:03in keeping that gas out.
27:05This quits the brakes on star formation
27:07and keeps new stars from forming
27:09as fast as we think they would in the Milky Way.
27:12The galactic magnetic fields
27:14not only reduce the rate of star formation,
27:17new evidence suggests
27:19they also determine the regions
27:21where the stars that do form are born.
27:24Making it more likely for stars to form
27:26along the web of magnetic field lines
27:29that weave through the galaxy.
27:34Thus shaping the distribution of stars,
27:37including our own star,
27:39the Sun.
27:43Clues for this magnetic blueprint
27:45came from a galaxy 2.7 billion light-years away.
27:49The Triangulum Galaxy
27:51boasts spectacular spiral arms.
27:54Stars are bursting into life
27:56all neatly lined up along them.
27:58Astronomers realized
28:00that the spiral arms
28:02traced out the galaxy's magnetic fields.
28:05What we're beginning to see right now
28:07is that it looks like we're discovering
28:09these gas clouds where stars are forming,
28:11and that's what we're looking for.
28:13We're looking for stars
28:15and it looks like we're discovering
28:17these gas clouds where stars are forming
28:19that are aligned.
28:21And one way that this alignment could occur
28:23is via the act of magnetic fields.
28:26Magnetic fields lines act sort of like
28:28superhighways for charged particles.
28:30Charged particles want to track along them.
28:32Charged particles in gas clouds
28:34within the galaxy
28:36are directed along the spiral arms
28:38by magnetic fields.
28:40Here the gas clouds are denser,
28:43allowing star formation to take place.
28:46Gravity is responsible for the formation of galaxies,
28:49but magnetism may make galaxies what they are.
28:57Magnetism has shaped the galaxy.
29:05But it's also responsible for protecting us
29:07from our nearest and most dangerous threat,
29:11the sun.
29:13The sun's scale and power is almost unimaginable.
29:17It burns a staggering 5 million tonnes
29:20of nuclear fuel every second.
29:23The energy it releases powers most life on Earth.
29:33But without magnetism to tame it,
29:36our star would destroy us.
29:42The spinning molten core of Earth
29:44generates a magnetic field
29:46that bursts from the poles,
29:49cocooning our entire planet in a blanket of magnetism.
29:53This invisible force field
29:55deflects deadly charged particles
29:57streaming from the sun,
29:59protecting us and our atmosphere
30:01from catastrophic damage.
30:04But this vital shield might be losing its power.
30:12In the last about 200 years,
30:14it's weakened by about 10%.
30:16And if it continues at this rate in a couple thousand years,
30:19it might go down to nothing.
30:21If it were to disappear forever,
30:23we would be in trouble in the long run.
30:27Our planet without magnetic protection would be doomed.
30:32We only have to look at our planetary neighbor
30:35to see what would happen.
30:38Mars may have once been like Earth
30:40with a thick atmosphere and water on its surface.
30:43That's gone. Why?
30:45Well, we know Mars doesn't have a very strong magnetic field,
30:48and that means it can't protect itself from the solar wind.
30:52These particles come streaming out of the sun
30:54and they hit Mars' atmosphere and blow it away.
30:58Its atmosphere was actually stripped off by the solar wind
31:01because it didn't have a protective cocoon of a magnetic field.
31:04Today, if you look at Mars,
31:06it's cold, it's barren, it's lifeless,
31:08because it doesn't have an atmosphere.
31:15Understanding the Earth's magnetic field
31:18is key to understanding our future survival on this planet.
31:26Geophysicist Dan Lathrop and his team
31:29have built a replica of the Earth's core
31:31to play out the evolution of magnetic fields in fast forward.
31:38Lathrop wants to know if the Earth's magnetic decline
31:41is part of a normal cycle of peaks and troughs,
31:44or if it signals the beginning of a terminal decline.
31:52Having an experiment like this allows you to get closer
31:55to something like a planetary core
31:57than could ever be done by any other means.
31:59Liquid iron is too hot to handle,
32:02so Lathrop fills his ten-foot ball with the next best thing,
32:0612.5 tonnes of liquid sodium metal.
32:10When we run the experiment,
32:12the main thing that we're trying to understand
32:14is how the swirling mass of liquid sodium,
32:16this turbulent, roiling flow of liquid metal,
32:19generates electric currents and magnetic fields
32:22and try to use that then to understand
32:24how planets' interiors do the same thing.
32:30Lathrop starts the motor, spinning the ball,
32:34replicating how our planet rotates.
32:39Inside the spinning ball, the molten sodium starts to swirl.
32:45Charged particles race around the core.
32:52OK, yeah, that's good. It's coming into view.
32:56A magnetic field emerges from the poles of the ball.
33:00It looks just like the one that protects the Earth.
33:04Spontaneously, the magnetic field starts to weaken,
33:08but then recovers again.
33:11Lathrop believes the Earth's magnetic field will also recover,
33:15and his experiment shows something else.
33:19The magnetic poles are moving.
33:23Amazingly, scientists have found that the Earth's poles do the same.
33:30As we look at the Earth's magnetic field,
33:32we can see that the direction the compasses are pointing toward
33:35is migrating to the north at a rate of several tens of miles per year.
33:40It's migrated off of Canada. It's moving now towards Siberia.
33:44Will it keep going to Siberia and beyond that,
33:47or will it come back again and reach toward Canada?
33:50It's hard to predict what will happen.
33:53To try and predict the future,
33:55scientists search for clues in our planet's magnetic past.
34:02Planetary scientist Janie Radabaugh is in Hawaii,
34:06home to Kilauea, the world's most active volcano,
34:10making it the perfect natural lab to study Earth's magnetic history.
34:16The great thing about lava flows
34:19is that they trap the Earth's magnetic field inside of them
34:22and then freeze it in place.
34:25So now if we go and pick up the rocks from these lava flows,
34:29we can actually find out the orientation of the magnetic field in the past.
34:40Lava contains particles of iron.
34:43When molten, these iron particles line up with the Earth's magnetic field.
34:48Then, as the lava cools, this orientation is locked in place.
34:58By digging down through layers of historic lava flows,
35:02scientists have discovered a magnetic record
35:05that stretches back for millions of years.
35:09It shows the Earth's field doesn't just weaken and move.
35:16From time to time, the whole field flips.
35:21The North and South Poles actually swap places.
35:27The field was aligned in one direction for a while,
35:30and if you come up a little ways higher in that column of lava rock,
35:35we find it's actually oriented completely the opposite direction,
35:39180 degrees from where it is today.
35:42It does that a number of times, dozens of times.
35:45So that tells us that the magnetic field of the Earth changes direction,
35:49not on kind of a regular basis, but once in a while,
35:52spaced by tens of thousands of years,
35:55maybe up to a couple of million years apart.
35:58And it flips from north to south,
36:01changing directions over the course of Earth's history.
36:06How will the next magnetic somersault affect life on Earth?
36:11The surprising answer, very little.
36:16Biologists have dug deep into the Earth's fossil record
36:19and discovered that magnetic flips aren't cataclysmic.
36:24What we do know is that it doesn't take so long that we're left unprotected
36:28for a long enough time that life is wiped out.
36:30We don't see mass extinction events around every magnetic field flipping event,
36:35and therefore we know it must be relatively fast.
36:42The Earth's magnetic shield
36:44has protected life from the sun's radiation for billions of years.
36:50And it will continue to do so.
36:54But we are different from our ancient ancestors.
36:58We harness the force of electromagnetism
37:01in every device that powers our technology.
37:06And this puts us at risk
37:08from a threat that could bring the human race to its knees.
37:14The Earth's Magnetic Shield
37:25The human race could be heading towards a major catastrophe of our own making.
37:31We've built our entire civilization on electromagnetic foundations.
37:36And there's a threat in the sky that could bring it all down at any moment.
37:44We depend on the sun for our life and for our civilization,
37:48but it can just as easily take that away.
37:52We have wires running everywhere, and they're used to carrying currents.
37:55But this infrastructure is in some level vulnerable to activity on the sun.
38:01Day after day, we're protected from the sun's solar wind
38:05by our planet's magnetic field.
38:09But the sun has a magnetic field, too.
38:13And sometimes its magnetic lines become weapons of mass destruction.
38:25These magnetic weapons are generated deep inside the star.
38:30The sun is hot on the inside, and that hot material rises up from the center
38:34and goes out toward the surface and back down.
38:37This process is called convection.
38:39And so these charged particles are moving around and generating a magnetic field.
38:43Now, unlike the Earth, which has one big magnetic field like a bar magnet,
38:47inside the sun, there are zillions of little magnetic fields
38:51all rolling around and doing their own thing.
38:54A surprising feature of the sun's surface further distorts this chaotic web of magnetic fields.
39:01The whole sun spins, but it's not a solid object.
39:04The equator actually spins faster than the poles, and the sun twists itself up.
39:09When you twist magnetic fields, they get more energized.
39:15Magnetic fields can store a vast amount of energy, and the sun has that to spare.
39:19Now, if that were it, it wouldn't be a problem.
39:22But what happens is sometimes these magnetic lines can snap.
39:26When a magnetic field snaps, the surface of the sun erupts,
39:32blasting out a magnetically charged cannonball of particles.
39:37This is called a coronal mass ejection, or a CME.
39:44A coronal mass ejection blasts out this energy.
39:47There's a huge amount of subatomic particles, something like a billion tons.
39:51There's a huge amount of subatomic particles, something like a billion tons,
39:55which will erupt out from the sun and head out into interplanetary space.
40:00This cloud of particles has its own magnetic field that goes with it,
40:04and if that hits the Earth, it can interact with our magnetic field.
40:09When a CME smashes into Earth's magnetic field,
40:12the impact can induce a surge of current in the power lines
40:16that deliver electricity to homes and businesses.
40:21All of our electromagnetic infrastructure, all the power lines, the transistors, everything,
40:26all of that can absorb this current and it can overload the circuit,
40:30causing blackouts and a lot of annoyance to society.
40:35Around 150 CMEs hit Earth each year.
40:40Some cause blackouts, but nothing worse.
40:45However, the sun has the potential to fire a doomsday CME our way.
40:58First, the huge ball of charged particles would smash into satellites orbiting the Earth.
41:05A big solar storm could actually affect satellites, shorting them out.
41:09We could lose communication. We could lose GPS.
41:14GPS is used by every stock market across the globe.
41:18Without satellites, the world's financial infrastructure could crash.
41:26Aeroplanes would be grounded in space.
41:30Shipping lanes closed.
41:33Mobile communications would go dead.
41:36We depend on all of this for our monetary system, financial system, for our civilization.
41:43After destroying satellites, the energy of the CME would reach the surface.
41:50Immense electrical currents would surge through power lines.
41:55Overloading entire grids across the planet.
42:01Substations explode in a shower of sparks.
42:08You can imagine an extreme solar event, an explosion like we've never seen before,
42:13causing tremendous power outages.
42:15You could even imagine all of the United States having a massive blackout.
42:19It would take years and billions of dollars to fix the electrical infrastructure
42:24and build and launch new satellites.
42:27A huge storm could actually bring our civilization to its knees.
42:35Magnetism threatens to destroy our society.
42:39But our electromagnetic habit is a hard-to-break habit.
42:43Magnetism threatens to destroy our society.
42:46But our electromagnetic habit is a hard one to give up.
42:51This same force protects us, allowing life to flourish on our planet.
42:57It helped build our sun, and even the galaxy we sit in.
43:02Without magnetism, there would be nothing.
43:06Magnetism affects processes that range from the formation of galaxies
43:12to the formation of stars to the processes that power our very being.
43:17Magnetism is central to our existence in the universe.
43:24From the atom up, magnetism shapes every object in the cosmos.
43:33It really is the ultimate force of mass construction.
43:38It's responsible for the very nature of matter itself.
43:42It's responsible for the Earth holding on to its atmosphere and its water.
43:46Every day of your life, you have to remember you're here because of magnetism.