What happens if you drop 0.125 grams of antimatter?
Veritasium
0:00 There is a prequel to the "Da Vinci Code".
0:02 It's called "Angels and Demons".
0:04 And in it, terrorists steal one eighth of a gram
0:07 of antimatter from CERN to try to blow up the Vatican.
0:11 Because the thing is, when antimatter and matter meet, they annihilate,
0:15 turning nearly 100% of their combined mass into pure energy.
0:20 This is via E equals mc squared.
0:23 It is the most violent process physics allows.
0:28 Let's go!
0:30 Oh my God.
0:31 (dramatic music)- Now, that was just a novel.
0:34 But CERN actually is making antimatter.
0:37 And we got to visit it.
0:40 This is CERN's antimatter factory.
0:43 There's antiprotons...
0:45 Yes.
0:45 Going beneath our feet.
0:46 They are under our feet at this time.
0:48 Here, protons are accelerated up to 99.93% the speed of light
0:54 and smashed into an iridium target
0:56 to produce 20 million antiprotons every minute.
1:00 This is so much bigger than I was thinking.
1:03 This is crazy.
1:04 Antimatter is the most expensive substance in the universe.
1:07 $1 billion per gram.
1:09 No way.
1:10 Go up.
1:11 You're missing zeros here.
1:13 And CERN makes it to do something that seems impossible.
1:17 So you're making antiatoms?
1:19 Yes.
1:20 CERN made the first antihydrogen atoms back in 1995,
1:23 but they quickly ran into a problem because those antiatoms
1:27 only survived for 40 billionths of a second before annihilating,
1:32 which is way too short to do anything useful with it.
1:35 If only they could figure out how to store antimatter,
1:38 then they could study it and try to find
1:40 ways in which it might differ from normal matter.
1:43 They knew that any unexpected difference could reveal entirely new physics.
1:48 So how do you store antimatter in a world full of matter?
1:53 Well, that's one of the problems CERN has
1:56 been obsessing over for the last 30 plus years.
1:59 It has allowed them to do some of the most precise tests of antimatter to date,
2:04 and they even managed to trap antimatter in a box,
2:07 load it onto a truck and ship it.
2:10 And they are doing all of this to try and solve
2:13 one of the biggest unsolved mysteries in all of physics.
2:18 To understand it, we must go back to a discovery made around 100 years ago.
2:25 Previously on "Veritasium," we learned how a strange physicist, Paul Dirac,
2:30 came up with an equation to unite special relativity with quantum mechanics.
2:34 It worked surprisingly well, but Dirac was stumped by his own equation,
2:38 because the solution for an electron at rest was kind of strange.
2:42 There were two possible energies,
2:44 E equals mc squared and E equals minus mc squared.
2:49 But how could an electron have negative energy?
2:52 Well, instead of throwing away his negative energy solution,
2:55 Dirac ended up proposing something radical.
2:58 This negative energy solution corresponded to an entirely new particle,
3:02 unknown to physics at the time.
3:05 It would have the same mass as an electron, but carry opposite charge.
3:09 It would be an antielectron, or positron.
3:13 Miraculously, a year later,
3:15 the first positron was observed by accident in nature.
3:19 Over the following decades, physicists built on Dirac's equation to form
3:24 an entirely new framework of quantum mechanics, quantum field theory.
3:29 This didn't just explain why there are antiparticles,
3:31 but it also answered a more fundamental question,
3:34 which is, why is every electron in the universe exactly the same?
3:40 The answer began to take shape when people figured
3:43 out that fundamental particles aren't just particles or waves,
3:47 but rather excitations of a quantum field.
3:50 So you'd have an electron field that permeates all of space,
3:53 and this field can get excited, but only in identical, discrete units,
3:59 each with the same mass, spin, and charge.
4:02 And that's why every electron is the same.
4:05 They're all excitations of the same field.
4:07 Now, you could have several excitations,
4:10 that would be several electrons, and they can move around too.
4:14 The only requirement is that they can never overlap exactly.
4:18 Of course, there is nothing special about this kind of excitation.
4:21 You could just as well have a mirror opposite.
4:24 In fact, the equations that describe
4:27 this field require such excitations to exist.
4:30 They have the same mass and spin, but with opposite charge.
4:34 This is the idea of an antielectron, or positron.
4:39 It's exactly what that minus sign in Dirac's equation was revealing.
4:44 And just like an electron, positrons can move around too.
4:47 Only positrons can overlap with electrons.
4:51 But watch what happens when they do.
4:53 Now, I'm simplifying a little here,
4:55 but because they're each other's mirror images,
4:58 the opposite charges cancel each other out,
5:01 the excitations disappear, and the field returns back to its ground state,
5:06 but that would predict that the particles just disappear.
5:09 So how is that possible?
5:11 Where did the mass go?
5:12 Well, the only way this could work is
5:15 if that mass got converted into something else,
5:18 energy, according to E equals mc squared.
5:21 The energy got transferred into a different quantum field,
5:25 the photon field, and that is what we mean by annihilation.
5:30 Now, people realize that most fundamental particles
5:33 could be described using the same approach,
5:35 where each could be seen as an excitation of their very own quantum field.
5:40 Now, this meant two things.
5:42 The first is that most particles must have an antiparticle twin,
5:46 because they're just mirror excitations in the same field.
5:50 There are some exceptions though,
5:52 like the photon and Higgs boson, which are their own antiparticle.
5:56 And the second and more important implication is that each
6:00 antiparticle must be exactly equal to a normal particle,
6:04 just with the opposite charge.
6:06 But then, around the mid 1960s,
6:09 people realized that there was a big issue with this explanation.
6:13 And it all stemmed from how it fit in with the newly accepted Big Bang theory.
6:19 In the very first moments after the Big Bang,
6:22 the universe was extremely hot and dense, and photons had so much energy
6:27 that the reverse process of annihilation happened.
6:30 So two photons could come together and spontaneously convert their energy
6:33 into the mass and kinetic energy of a particle-antiparticle pair.
6:38 And so, the universe was filled with these pairs
6:41 continuously popping into and out of existence.
6:43 But as the universe continued to expand,
6:47 it cooled, and those photons lost energy.
6:50 Until around three seconds after the Big Bang,
6:52 they had lost so much energy that pair production stopped.
6:57 And this is what troubled physicists in the 1960s,
7:01 because they believed that in those initial stages,
7:03 an equal amount of matter and antimatter should have been created.
7:08 But if an equal amount of matter and antimatter were created,
7:12 then every particle should have found its antiparticle twin, and annihilated.
7:18 Meaning there should be no stuff around us,
7:20 no matter and no antimatter, just photons, only radiation.
7:26 So this became known as the Big Bang radiation catastrophe.
7:30 Because clearly, when we look around us, we see a lot more than just energy.
7:36 The universe is filled with matter.
7:38 But how can that be?
7:40 Why is there now more matter than antimatter in the universe?
7:44 Where did that asymmetry come from?
7:46 Well, that is one of the biggest unsolved mysteries in all of physics.
7:52 Initially, some people tried to brush this away,
7:55 and they argued that perhaps there is no asymmetry at all.
7:59 Maybe we happen to be in a pocket that because of blind random chance,
8:03 some reasonable statistical fluctuations, we're mostly surrounded by matter,
8:08 and there'd be some region that would, again, be like, like a Marvel movie,
8:11 like some mirror universe, that we're most slightly,
8:13 you know, imbalanced in the other direction.
8:16 [Casper] Paul Dirac seemed to have favored this approach.
8:18 He argued that there might be entire antistars,
8:21 and he ended his 1933 Nobel lecture by saying,
8:24 "There may be half the stars of each kind.
8:27 The two kinds of stars would both show exactly the same spectra,
8:30 and there would be no way of distinguishing them by present
8:35 astronomical methods." Physicist Edward Harrison took this one step further,
8:39 saying there should even be entire antigalaxies.
8:44 And then people realized, well, if that's the case,
8:45 there'd be regions where these boundaries where the two regions would meet,
8:49 and that should be lighting up the sky.
8:51 There should be tons of matter-antimatter annihilation.
8:54 There should be tons of very high energy light.
8:57 So people surveyed the sky looking for these hotspots, but they didn't find any.
9:02 And so this possibility was ruled out.
9:05 There really is more matter than antimatter in our universe.
9:08 There really is an asymmetry.
9:10 So the next obvious question is, well, how large is that asymmetry?
9:15 If we go back to around 10 seconds after the Big Bang, we can figure it out.
9:21 By this time, pair production had long stopped, a full seven seconds ago.
9:26 And by now, just about every antiparticle had
9:28 annihilated with its particle counterpart and turned into photons.
9:33 Now the universe was filled with just some leftover particles,
9:36 like electrons and protons whizzing around at incredible speeds,
9:40 and those remnant photons.
9:42 But because these electrons and protons were traveling so fast,
9:46 they couldn't come together to form atoms.
9:48 So you had this plasma of charged particles,
9:51 and that meant that when photons were going around,
9:53 they scattered off those charged particles.
9:56 So they couldn't travel very far without interacting with matter.
9:59 That all changed around 380,000 years after the Big Bang.
10:04 By now, the electrons and protons had slowed down enough to form neutral atoms,
10:09 and photons could only be absorbed by electrons in atoms if they
10:12 had exactly the right energy to move the electron up an energy level.
10:17 In practice, this meant that photons
10:19 could now basically travel through space unimpeded.
10:23 Those atoms then went on to form all the stars and galaxies,
10:26 and those photons stuck around too.
10:29 They've gone on to make up the low-level
10:31 radiation that permeates the entire observable universe,
10:35 the Cosmic Microwave Background, or CMB.
10:39 And when we estimate the total number of photons in that CMB,
10:43 we find that there are about 10 to the 89.
10:46 And because almost all of those photons were originally
10:49 created during those very first seconds after the Big Bang,
10:52 that original annihilation, we can infer that there must originally have
10:57 been around 10 to the 89 particles and antiparticles.
11:01 Now, we can also estimate how many ordinary matter particles,
11:04 like protons and neutrons, there are in the observable universe today,
11:09 the ones that survived that annihilation.
11:12 And what we find is that there are about 10 to the 80.
11:15 So that means that for every billion antimatter particles
11:19 and billion matter particles there were in the early universe,
11:22 when they annihilated, they did so almost perfectly.
11:26 But there was one, one out of a billion matter particles that somehow survived.
11:31 And everything we see around us today is
11:33 a descendant of those lucky one in a billion particles.
11:38 Every person, animal, jungle, and ocean,
11:41 every asteroid colliding or galaxy spiraling,
11:44 every single dot of light in the night sky is made
11:47 up of one of those lucky one in a billion particles.
11:52 And that brings us to the craziest part.
11:55 Because it tells us that there must
11:57 be a difference between matter and antimatter.
12:00 And how they evolve according to the laws of physics.
12:03 But it's not just any difference.
12:05 No, it would make sense if they behaved completely different.
12:08 I mean, you would just have different
12:09 laws of physics governing each type of particle.
12:12 Or it would make sense if they were governed by the exact same laws.
12:16 But in that case, there would be no difference.
12:19 It would be completely symmetric.
12:21 What's really weird here is that the laws are almost exactly the same,
12:25 but with a tiny difference.
12:28 And that doesn't make any sense.
12:30 For the past 70 years,
12:32 physicists have tried to explain where this asymmetry comes from.
12:36 But so far, all attempts have failed.
12:39 And part of the reason this has been so difficult
12:41 is because our laws of physics are full of symmetry.
12:48 In the mid 1950s, there were three
12:50 symmetries all particles were believed to obey.
12:53 Charge, parity, and time reversal symmetry.
12:56 Charge symmetry is super simple.
12:58 It just means that if you swap all positive charges with negative ones,
13:02 and vice versa, then the interactions don't change.
13:06 In other words, there is nothing special about a positive or negative charge.
13:10 Just that one is exactly equal and opposite to the other.
13:15 To understand parity symmetry, consider this mirror,
13:18 which creates a sort of parallel universe
13:20 where everything is the same, but reflected.
13:23 So my left hand becomes my right hand and vice versa.
13:26 Now take this molecule here, which is L-alanine,
13:30 an important amino acid we need to make proteins.
13:33 Now that L is in its name because the amine group,
13:36 this NH2 part over here, is on the left.
13:38 But in the mirror, you see its sister molecule,
13:42 D-alanine, that NH2 part is now on the right.
13:45 And if you try to make alanine in a lab,
13:47 you'll find that you'll get 50% L-alanine and 50% D-alanine.
13:51 In other words, there is no experiment you could do
13:54 that determines whether you're in our universe or in the mirror universe.
13:59 And the same is true for many left and right handed molecules.
14:02 If you just try to make them normally in a lab, you'll get 50% of each.
14:07 So our universe doesn't favor left or right handedness.
14:10 Lastly, time reversal symmetry means that the laws of physics
14:14 work the same whether time is running forwards or backwards.
14:18 Now, out of all of these, time reversal symmetry might feel strange.
14:22 Because there are many things that clearly don't work backwards in time.
14:27 You can't uncook an egg, unshatter a wine glass,
14:30 or turn a plant back into a seed.
14:33 But all of these follow from the second law of thermodynamics,
14:36 which describes how many interacting particles evolve from less likely states,
14:41 typically more ordered, to more likely states, typically a mess.
14:45 But this is a statistical law, it's not a fundamental law of physics.
14:49 If you zoom in to the level of individual particles,
14:53 then every interaction is perfectly reversible.
14:56 You can tell whether these collisions happen forwards or backwards in time.
15:00 Now the combination of all of these symmetries combined is called CPT symmetry.
15:05 And CPT symmetry, it turns out, is kind of a big deal.
15:09 What happens if CPT gets broken?
15:12 Well literally cats and dogs start living together, time flows backwards.
15:14 All kinds of things start breaking in our description of nature.
15:18 Now one of the reasons why CPT and the standard model go so well
15:22 together is because it really is built
15:25 into the very structure of special relativity.
15:28 The special relativity is built on one core principle.
15:31 Which is that the laws of physics are the same for all inertial observers.
15:36 And this includes any measurement they make of the speed of light.
15:41 In the 1950s, Julian Schwinger, Gerhart Lüders,
15:44 and Wolfgang Pauli proved that if our universe obeys this principle,
15:48 which we strongly believe it does, then it must be CPT symmetric.
15:53 But the reverse is also true.
15:55 If you break CPT symmetry, then this core principle also breaks.
15:59 And that's where things get tricky.
16:02 Because after Dirac united special relativity with quantum mechanics,
16:05 all following quantum theories also incorporated special relativity.
16:10 And so our best theories of reality,
16:12 quantum field theory and the standard model,
16:14 are built on that exact same principle.
16:17 So now we have a paradox.
16:19 Because on the one hand we need asymmetry to explain why we're here.
16:24 But on the other hand, if CPT symmetry breaks,
16:27 it tears down our best theories with it.
16:30 So physicists started off on a hunt for a special kind of asymmetry.
16:35 An asymmetry that could explain that one in a billion discrepancy,
16:38 while also maintaining the larger CPT symmetry.
16:42 The first clue that such asymmetries might exist came in the mid 1950s.
16:47 Up until then, every interaction that had been studied
16:50 conserved the individual symmetries of C, P and T.
16:54 And so conserved CPT as a whole.
16:56 But in 1956, theoretical physicists Tsung-Dao
16:59 Lee and Chen-Ning Yang realized that no
17:02 one had checked whether parity is conserved in the weak nuclear force.
17:07 So they set out to test whether the universe favored left or right handedness.
17:12 And to do it, they enlisted the help of one of Lee's colleagues,
17:15 one of the world's best experimentalists,
17:18 Chien-Shiung Wu, also known as Madame Wu.
17:22 Once the idea of the experiment was pitched to her, then she just went all in.
17:26 She canceled trips, she worked straight over holiday breaks.
17:29 It was really an all hands on deck operation over a very frenzied few months.
17:34 When Pauli learned of the experiment, he said,
17:37 "I do not believe that the Lord is a weak left-hander,
17:40 and I am ready to bet a very high sum that the experiments will
17:44 give symmetric results." Now all that was left to do was run the experiment.
17:50 It worked something like this.
17:53 She started with cobalt 60, an isotope of cobalt where the nucleus
17:57 has an intrinsic angular momentum, or spin.
18:00 When she applied a strong magnetic field,
18:03 she forced all the spins to point in the same direction.
18:06 But cobalt 60 is also radioactive.
18:09 So every once in a while,
18:10 a neutron inside one of its nuclei decays into a proton,
18:15 releasing an electron and antineutrino, and leaving a nickel 60 atom behind.
18:20 Now the electrons emitted could travel in two directions.
18:24 They could either go in the same direction as the nuclear spin,
18:27 or they could go in the opposite way.
18:30 But if spin is clockwise in our universe,
18:33 then it is also clockwise when reflected in the mirror.
18:36 Which means it points in the same direction in both universes.
18:40 So the only way the experiment could be
18:43 the same in our universe and the mirror universe,
18:46 is if the electrons were emitted in equal amounts in each direction.
18:50 It should be 50% on each side.
18:53 But what Wu actually found was that around 60%
18:56 of the electrons moved in the opposite direction to the nuclear spin.
19:00 Which would mean that 60% moved in the same
19:03 direction as the nuclear spin in the mirror universe.
19:06 But that meant that there is an experiment you could do
19:09 to tell whether you are in our universe or the mirror universe.
19:13 So it proved that parity is not conserved.
19:16 This shocked the physics community.
19:19 Pauli, upon being informed of the results, exclaimed,
19:22 "That's total nonsense!"- Very smart people,
19:25 Nobel Laureates said, that can't be right.
19:28 Do it again.
19:29 I don't believe it.
19:31 You know, and in a sense you can see where they're coming from.
19:35 There have been no hint as yet that kind
19:37 of the universe would care whether I'm looking at myself,
19:41 you know, in a mirror or not.
19:43 So others repeated the experiment and by 1957
19:46 there was no further room for doubt.
19:49 God really was a weak left-hander.
19:53 That same year, Lee and Yang won the Nobel
19:55 Prize in Physics for the discovery of parity violation.
19:58 But Wu's name was left off.
20:00 Lee and Young acknowledged her during their speech and tried
20:03 to get her nominated for a prize another year.
20:06 But the Nobel committee never honored her.
20:08 In a way, she was robbed of the Nobel Prize.
20:11 1988 winner Jack Steinberger called this the biggest
20:14 mistake in the Nobel committee's history.
20:17 But her work had done something important.
20:19 It had cast doubt on the long-held belief that charge,
20:23 parity, and time reversal were fundamental symmetries of our universe.
20:28 This made many physicists uncomfortable.
20:30 So they came up with a workaround.
20:33 Maybe it's okay if parity symmetry was broken.
20:36 Because that's not a fundamental symmetry of nature.
20:38 It's just part of a larger symmetry, charge parity.
20:42 The idea was that if you reflected everything
20:45 in a mirror and swapped all the particles for their antiparticles,
20:49 then the symmetry would be restored and all would be good again.
20:54 But then, seven years later, two physicists found that some particles
20:58 also violated the combined charge parity symmetry.
21:01 Now physicists were getting really nervous.
21:04 Two symmetries that they believed were
21:06 fundamental parts of our universe were broken.
21:09 So the next big question on everyone's mind was,
21:11 is CPT symmetry also going to fail and take down the standard model with it?
21:18 Then, in 1973, something seemingly miraculous happened.
21:22 Makoto Kobayashi and Toshihide Maskawa found a way to explain
21:27 all the observed P and CP violation while maintaining CPT symmetry.
21:32 And it all fit directly within the standard model.
21:36 The only issue is that when it comes to the matter-antimatter asymmetry,
21:40 it can only account for an asymmetry of 10 to the minus 18.
21:44 Which is a billion times less than
21:47 we need to explain the observed matter-antimatter asymmetry.
21:51 So the ingredients are there,
21:53 which is cool because we didn't think even the ingredients were there.
21:55 Right.
21:56 But they're not there in a large enough strength.
21:58 You don't have a strong enough rate of CP
22:02 violation if you just stick with strictly the standard model.
22:05 And so are people now getting nervous about CPT?
22:08 Not nervous, I'd say excited.
22:10 And that's because this means there is
22:11 likely new physics beyond the standard model.
22:14 But to find out what that might be, we must study antimatter up close,
22:19 to see if there are any ways in which it might be different from normal matter.
22:23 Ways that could explain that asymmetry.
22:26 So, you know where we're going.
22:28 Oh, look, there it is.
22:30 CERN, baby.
22:31 Woo-hoo!
22:32 CERN is best known for the Large Hadron Collider,
22:35 a 27 kilometer underground ring where protons are
22:39 accelerated up to 99.999999% the speed of light.
22:44 Beams traveling in opposite directions are smashed together,
22:48 releasing huge amounts of energy.
22:50 It's the closest we get to the high energy conditions of the early universe.
22:55 But at the southern edge of the LHC,
22:57 there is a smaller proton accelerator called the proton synchrotron.
23:02 Protons in this ring are only accelerated to 99.93% the speed of light.
23:08 And some of that proton beam is fed out of the ring and ends up here.
23:13 This is CERN's antimatter factory.
23:16 And in here, you make antiprotons.
23:18 How many?
23:19 Usually it's around 40 million every couple of minutes.
23:23 We are now going to enter the facility by actually a technical building,
23:27 which is not very interesting to watch.
23:30 [Casper] I find this all interesting to watch.
23:32 To make sure we're safe, we always had to carry around these devices.
23:36 So you've got two, what are they called?
23:39 Dosimeters.
23:40 Dosimeters?
23:41 Yes.
23:41 Yeah, just to be safe.
23:43 These are standard devices to measure the amount
23:46 of dose of radiation that you get.
23:48 This is a supervised radiation environment,
23:52 which means it's an environment in which we keep an eye
23:55 on to the amount of radiation we get as radiation workers.
23:58 Where are we going now?
23:59 So now we are going to enter into the main building.
24:04 [Casper] There's antimatter behind this door?
24:06 Yes, yes, under our feet.
24:08 Oh wow.
24:09 Yeah, you'll see, you'll see.
24:12 Please guys, welcome.
24:15 This is huge.
24:16 This is a huge place.
24:17 (dramatic music)- This is so much bigger than I was thinking.
24:23 This is crazy.
24:26 Well, I feel like I'm a kid in a candy store looking at this.
24:29 This place is pretty, is pretty fun, the first time you see it.
24:32 Yeah, it's so impressive.
24:34 Here you see pretty much the scheme of how this facility is working.
24:38 You get protons coming from one of the CERN accelerators,
24:41 the PS, which smash onto a target...
24:45 The protons are accelerated up to around 99.93% the speed
24:49 of light and have energies up to 26 gigaelectronvolts.
24:55 They're aimed at a remarkably small target, an iridium rod,
24:58 3 millimeters in diameter and 55 millimeters across,
25:02 which itself is embedded in a graphite and then in a titanium alloy structure.
25:07 Iridium was chosen because it's the second densest element on Earth.
25:11 And that means that there are a lot of nuclei packed in a small space,
25:16 which increases the odds that the protons will hit something.
25:19 But when one of these protons hits an iridium nucleus,
25:23 it doesn't bounce off like you'd expect in most collisions.
25:26 It is going so fast and has so much energy that it penetrates the nucleus,
25:32 where it collides directly with one of the neutrons or protons.
25:36 And to understand what happens next,
25:38 we need to look at what's going on inside the proton.
25:41 Because a proton is not a fundamental particle.
25:45 Instead, it is made up of three fundamental particles known as quarks,
25:49 specifically two up and one down quark.
25:52 Those quarks whiz around close to the speed of light.
25:55 So to keep all those quarks contained,
25:57 traveling at such incredible speeds and in such
26:00 a small space requires a very strong force.
26:04 Which is why it's called the strong force.
26:07 And it's mediated by particles known as gluons.
26:11 You can think of this force as acting like a rubber band.
26:15 But you can bring this past its breaking point.
26:18 If you keep putting in energy, then you can put in so much
26:21 energy that another quark-antiquark pair will be created.
26:25 This bond breaking into pair creation can happen several times
26:29 in a row and results in this sort of shower of quark-antiquark pairs.
26:34 And a similar thing happens when a proton collides
26:37 with a neutron or proton inside an iridium nucleus.
26:40 Now, most of those pairs stay just like that, pairs, and they travel off.
26:45 But occasionally, you will get two antiup
26:48 and one antidown quark to come close enough.
26:51 And they form a new particle made of three antiquarks.
26:55 They form an antiproton.
26:57 And their counterparts will go on to form a proton.
27:01 Now, all of this, this entire process from initial collision
27:05 to the shower of particles and the formation of the antiproton,
27:09 happened in the span of 10 to the minus 23 seconds.
27:13 That is a hundred billionth trillionth of a second.
27:17 It is absolutely insane.
27:19 And every time you hit the target, you get trillions of these collisions.
27:23 And out the other side comes a chaotic spray of protons,
27:28 antiprotons and a bunch of other particles,
27:31 all traveling at around 96% the speed of light.
27:35 Magnets then filter out the antiprotons from the other
27:38 particles and they're sent on to the next stage.
27:41 And then we collect these antiprotons, bring them into the ring,
27:45 the antiproton decelerator ring, which is the one we are staring on top of.
27:49 And then they circulate in there for a while, while they get cooled down.
27:53 So the idea here is really that we
27:55 get these antiprotons every two minutes, more or less.
27:58 It's about 30 million of them.
28:00 How expensive is it, antimatter?
28:02 Look guys, what is value?
28:04 It's a bit difficult to evaluate it, right?
28:06 For sure it's probably the most expensive state
28:08 of matter we can build on Earth today.
28:11 How about I name some numbers and you tell me if it's cheap or too expensive?
28:16 Shoot.
28:17 $1 billion per gram.
28:19 No way.
28:20 It's too cheap?
28:21 Orders of magnitude too cheap.
28:23 Like many orders of magnitude too cheap.
28:25 Yeah, that's what I was thinking.
28:27 $100 billion per gram.
28:29 No way, go up.
28:31 I think probably you miss other three zeros.
28:35 Three zeros?
28:36 I think so, per gram, yes.
28:38 At least.
28:39 That's crazy.
28:40 If you're wondering what you would do with all that money,
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29:45 And now back to antimatter.
29:53 There's antiprotons going beneath our feet.
29:56 Yes.
29:56 They are under our feet at this time.
29:58 Yes, indeed.
29:58 [Casper] And that's not dangerous?
29:59 No, no, it's not dangerous.
30:00 There is no risk whatsoever.
30:03 Strong electric fields in the decelerator slow down
30:06 the antiprotons from 96% to 10% the speed of light.
30:10 But that's still about 100 million kilometers per hour.
30:15 To do experiments with them, they need to be slowed down more.
30:18 Initially, this was done in a kind of crazy way.
30:22 The antiproton beam was fired at a thin plastic foil,
30:26 which annihilated 99.9% of all the antiprotons.
30:30 But around 0.1% of those antiprotons survived,
30:33 and they came out slow enough to do experiments with them.
30:37 Of course, this was very inefficient.
30:39 And so in 2015 and 2016, a secondary ring called ELENA was installed.
30:45 ELENA slows the antiprotons to 1.5% the speed of light,
30:50 a nice slow 16.2 million kilometers per hour.
30:56 This is running?
30:57 You are watching a live antiproton machine.
31:01 Are the antiprotons going around in these circles?
31:04 Exactly.
31:04 The blue devices are magnets, dipole magnets,
31:07 which by Lorentz force make the particles turn.
31:10 Then you have the orange ones, which are quadrupole magnets,
31:13 which manage the focusing of this beam.
31:15 They're like lenses for particles.
31:17 It's a pretty thin pipe almost that they go through.
31:21 Yeah, I mean you don't need much there, right?
31:23 Because as long as you don't bend the particles, they just want to go straight.
31:26 You need to keep good vacuum in there.
31:28 Very good vacuum in fact.
31:30 Otherwise they would annihilate.
31:31 And how often do you have annihilations in this loop?
31:35 In here?
31:35 Yeah, because you can't have a perfect vacuum.
31:37 Well, no, no, you have a bit of losses.
31:40 But you know, the entire process of catching, I mean from the moment of catching
31:44 to the moment of extraction to the experiments,
31:46 I think these days we are about 86% efficiency.
31:51 They have made it very efficient.
31:53 After the antiprotons have been slowed down in ELENA,
31:56 they are sent onto five different experiments.
31:59 Each of which is designed to study different properties of antimatter
32:02 to try and find ways in which antimatter behaves differently from normal matter.
32:08 One of the first experiments that was done,
32:10 which happened before the antimatter factory was built,
32:13 was testing whether the mass of a proton and antiproton are the same.
32:18 But to do that, it brings us back to our original problem.
32:21 How do you store antimatter?
32:23 The way they solved this problem is pretty clever.
32:26 They started with a tube, which was pumped down to a vacuum.
32:30 A superconducting magnet sits around this tube,
32:33 and it creates a magnetic field that confines charged particles to the center.
32:38 At the same time, electrodes generate electric fields that function as end caps,
32:43 preventing the particles from escaping out the ends.
32:46 The whole tube is then cooled down to around 4 Kelvin,
32:49 or minus 269 degrees Celsius.
32:52 This causes almost all the remaining particles to condense and freeze,
32:57 resulting in a vacuum pressure comparable to outer space.
33:00 So now, they could fill this tube with something like antiprotons.
33:05 And once inside, those antiprotons have nothing
33:07 to annihilate with, and nowhere to go.
33:11 They are trapped.
33:13 They had just built a real-life antimatter trap.
33:16 The technical term for this is a Penning trap,
33:19 after Frans Penning, whose work inspired the first one.
33:23 Fittingly, the team that did this at CERN was called TRAP.
33:26 With the antiprotons trapped,
33:29 they measured the charge-to-mass ratio of the antiproton
33:32 and compared it to that of the proton.
33:34 And they found it was equal to one part in 10 billion.
33:39 Now, the Penning traps made studying antimatter much easier.
33:43 And so, it became a key tool that the other experiments at the factory adopted.
33:48 In 2017, the base experiment used
33:50 it to measure the antiproton's magnetic moment.
33:53 And they found that, within their level of accuracy,
33:56 it was equal and opposite to that of the proton.
34:00 So, thus far, everything was behaving just as predicted.
34:04 But there is one force that they hadn't directly probed yet.
34:08 Gravity.
34:09 Gravity.
34:10 Could that be part of the solution?
34:12 It very likely will be, ultimately.
34:14 Part of why is because gravity does not obey the rules of special relativity,
34:19 which means it doesn't have to obey the CPT theorem like the CERN model does.
34:24 And so, in principle,
34:25 that's an area within which one could more naturally expect larger values
34:31 of violations of C and CP and so on, or even a CPT altogether.
34:36 In fact, back in the 1950s,
34:38 a few physicists entertained the idea of antigravity,
34:41 that antimatter would be gravitationally repulsive.
34:44 So, while matter falls down in the Earth's gravitational field,
34:47 antimatter would rise up.
34:49 If you had a basketball made of antimatter, that would be easy to test.
34:52 But getting a basketball of antimatter without
34:53 it blowing up on you is pretty hard.
34:55 So...
34:57 It's not an easy thing to do gravity experiments on particles.
35:02 You can't just drop an antiproton and see if it falls.
35:05 Because antiprotons are negatively charged.
35:07 And the electric force is much stronger than gravity.
35:10 So, even small stray electric fields would
35:12 influence them way more than gravity would.
35:15 So what you need is something neutral.
35:18 What you need is an antiatom.
35:21 So you're making antiatoms?
35:23 Yes.
35:24 How do you make the antiatom?
35:26 So, what we do is we use antiprotons and positrons.
35:31 Basically, we merge them.
35:33 They become antihydrogen.
35:35 [Casper] Now, there are several ways to make antihydrogen.
35:38 And different experiments do it in different ways.
35:41 But for GBAR, it all starts here, in this bunker.
35:45 [Patrice] In this bunker, we have a small accelerator.
35:48 So, we make ourselves our own positrons.
35:51 And then we capture them in a trap here.
35:55 They accelerate a beam of electrons up to 99.9% the speed of light,
36:00 and then fire those at a tungsten target.
36:03 Now, while tungsten itself is electrically neutral,
36:06 at the high speed those electrons enter the tungsten,
36:09 they get close enough to the nuclei that the electron
36:12 cloud can no longer screen the intense positive charge within.
36:16 Thus, these nuclei create strong electric fields.
36:19 And those fields then yank the electrons around,
36:22 causing them to rapidly decelerate, as if they've just slammed on the brakes.
36:26 But the thing is, when these electrons break,
36:30 they lose energy by emitting photons.
36:32 The Germans have a great word for this.
36:34 It's called Bremsstrahlung, or breaking radiation.
36:38 This breaking radiation produces a wide range of photons,
36:42 ranging from low-energy X-rays all the way
36:45 up to nearly 9-megaelectronvolt gamma rays.
36:48 Now, out of all of these photons,
36:51 it's the gamma rays above roughly 1-megaelectronvolt that are important.
36:56 Because when one of these gamma rays passes close to a tungsten nucleus,
37:00 there's a chance that it transfers its momentum to that nucleus and converts
37:04 all its energy into the mass and kinetic energy of an electron-positron pair.
37:10 But unfortunately, this isn't a clean
37:12 process that just makes electron-positron pairs.
37:16 It produces positrons,
37:17 but it also produces a lot of photons, gamma rays, neutrons.
37:21 And these are deadly.
37:23 And that particle mess creates two problems.
37:27 The first is that deadly radiation.
37:29 It's supposed to be one of the highest, strongest source of radiation at CERN.
37:35 This is one of the highest?
37:37 Yes.
37:37 If you enter while it is working, you die in 10 seconds.
37:42 You die in 10 seconds?
37:43 You cannot escape.
37:44 It's terrifying.
37:45 You melt from inside.
37:47 You melt from inside...
37:49 You're saying that way too casually.
37:51 (laughs) And the second problem is that what
37:53 comes out of the tungsten isn't a nice, uniform beam of positrons.
37:57 Instead, you get a shower of electrons, neutrons,
38:01 positrons and photons all mixed together,
38:04 all traveling at different angles and different speeds.
38:08 The first problem is solved by encasing
38:10 the entire setup with massive 1.2-meter thick, 67% concrete and 33% iron blocks.
38:19 And this is enough to shield us?
38:22 Yes.
38:22 Because it's photons?
38:24 Yes.
38:24 This is 1,400 tons.
38:27 Okay.
38:28 Okay, I feel a bit better now.
38:29 Is it running now?
38:31 No.
38:31 But even if it runs, we can sit just outside and it's okay.
38:35 Okay, so we're safe.
38:36 You wear your...
38:38 Your badge, the dosimeter.
38:40 Okay, so you would know?
38:41 Yeah.
38:42 But I guess 10 seconds, not...
38:43 Too late.
38:43 Too late.
38:45 Solving the second problem is a little more involved.
38:48 And it's honestly one of the coolest combinations
38:50 of physics and engineering I've ever come across.
38:53 So, strap in.
38:55 When the positrons leave the tungsten target,
38:57 some are traveling at a few percent the speed of light,
39:00 while others are traveling at more than 90% the speed of light.
39:05 Now, this massive spread makes it very hard to work with.
39:08 So we need to slow them down to around 0.34% the speed of light,
39:13 or around 3.7 million kilometers per hour.
39:17 The way they do this is kind of crazy,
39:20 because they shoot the positrons, remember, those are antiparticles,
39:23 at a mesh of ultra-fine 20-micrometer diameter tungsten wires,
39:28 which, of course, are made of normal matter.
39:31 When a fast positron enters the tungsten wire,
39:35 it immediately loses energy due to scattering off the tungsten atoms.
39:39 And this happens so fast that within around 10 picoseconds,
39:43 that is, 10 trillionths of a second,
39:46 the positron has slowed down to match the thermal energy of the tungsten.
39:51 But now, the positron is still trapped inside the wire.
39:55 So, from here on, through a random walk of collisions and scattering,
39:58 it needs to find its way out.
40:01 And if it bumps into an electron or gets stuck in a defect,
40:04 it never makes it out.
40:06 So you might expect almost none of these positrons to make it out.
40:10 And for almost all of them to find an electron and annihilate.
40:15 And you'd be right.
40:16 The efficiency of this process is terrible.
40:19 For every thousand fast positrons entering the mesh,
40:22 only about one comes out as a usable slow positron.
40:26 Another problem is that these positrons don't come out as a nice organized beam.
40:32 Instead, they are emitted at all kinds of angles.
40:35 So we need to find a way to focus them.
40:38 This is done by letting the shower of particles go through a solenoid,
40:42 which is a long coiled wire with a current running through.
40:46 That current creates a magnetic field inside the coil
40:48 that acts as a magnetic lens and focuses the positrons.
40:52 This lets us capture many of the positrons
40:55 emitted at wide angles that would otherwise be lost.
40:59 But right now we still have a mix of positrons, electrons, neutrons and photons.
41:05 So the next step is to separate these.
41:08 To do this, we use another magnetic field.
41:10 This curves the electrons one way into a beam dump.
41:14 The photons and neutrons, because they have no electric charge,
41:17 are unaffected, so they go straight through and are absorbed by shielding.
41:21 And the positrons, because of their positive charge,
41:24 curve the opposite way to electrons.
41:27 And they go on to the next stage.
41:30 Now we're left with a beam of just positrons.
41:33 The only issue is that because
41:35 of the terrible efficiency from slowing down those positrons,
41:38 each single shot only generates around 1,000 usable slow positrons.
41:44 But we need millions or even billions of slow positrons for the next stage.
41:49 So the solution is to accumulate the positrons in a particle trap,
41:54 where over several minutes it builds up a positron cloud of around
41:58 100 million or more positrons which is enough for the next stage.
42:04 I said you merge positrons and antiprotons, but we do even more complicated.
42:07 First we make positronium.
42:09 Positronium is a...
42:11 Positronium?
42:12 Yes.
42:13 [Casper] Positronium is an electron and a positron
42:15 orbiting each other like a binary star system.
42:18 It's an exotic form of matter and it
42:20 only lasts about one tenth to 142 nanoseconds,
42:24 before the two come together and annihilate.
42:27 The way they make this is by using strong magnetic fields to compress
42:31 the cloud of positrons and fire it at porous silicon dioxide films.
42:36 When these positrons enter these films,
42:38 they rip away electrons from their atoms.
42:40 And some of those electrons then bind with positrons to form positronium.
42:44 And then a part of that positronium diffuses out
42:47 of the films into the vacuum of the next stage,
42:51 the interaction chamber, where it's time for the final step.
42:56 So this is where, we prepare this here.
42:59 That's the positronium?
43:01 Yes.
43:01 That's crazy.
43:02 We send antiprotons to the positronium where it makes antihydrogen.
43:06 [Casper] Now, since positronium only survives for about 142 nanoseconds,
43:10 this needs to be timed perfectly.
43:13 So if you want to see where we catch the antiprotons...
43:17 Yes, I would love to see where you catch the antiprotons.
43:20 I was not expecting to get this close.
43:23 It's right here?
43:25 This.
43:26 That's awesome.
43:27 So we get the antiprotons here...
43:30 Yes.
43:30 And then what happens?
43:32 So it goes there inside this box.
43:35 [Casper] Yeah.
43:36 Inside the box it will meet the positronium.
43:39 There meets the positronium.
43:41 Kind of scared, honestly.
43:43 It sounds like there's music in here.
43:46 As the positronium enters the interaction chamber,
43:48 the antiproton beam needs to be fired through at that exact moment.
43:52 When done correctly,
43:54 around three million antiprotons or so pass through the positronium.
43:58 If all goes well, around one to a few
44:01 of those antiprotons steal a positron to create an atom of antihydrogen.
44:08 Okay, so we've got positrons coming through here, all the way through here.
44:12 This is where you capture the positrons...
44:13 Yes, we accumulate them.
44:14 You accumulate them.
44:15 And then you shoot them through there and you make the positronium.
44:18 And then you shoot that into that chamber so it mixes with the antiprotons.
44:23 Yep.
44:24 It's so cool.
44:25 It's so cool.
44:26 Right in here is where they make antiatoms.
44:30 Antihydrogen.
44:31 They shoot the antiprotons through and they capture,
44:35 they capture those antielectrons to form antihydrogen.
44:39 Which then travels through here and then, you know,
44:42 it will go all the way along there and they do their experiments.
44:46 It's absolutely insane.
44:47 I feel like I should not be in here, but it's so cool.
44:51 Now, one question I had after learning all of this is, why?
44:55 I mean, why do this?
44:57 Because the ALPHA-g experiment can already make 100 antihydrogen
45:00 atoms in four hours using a much simpler process.
45:05 So why is the GBAR team spending years to build a particle accelerator,
45:10 a positronium converter,
45:11 and a way to shoot the antiprotons through this positronium just
45:16 to make fewer antihydrogen atoms in a slower and more difficult way?
45:21 Especially when you consider that in 2023 ALPHA-g did its
45:26 own test to see whether antihydrogen falls up or down.
45:30 Well, to understand why,
45:32 we need to understand exactly what it is that ALPHA-g did.
45:36 Their setup works something like this.
45:39 Positrons are created by a radioactive source,
45:42 accumulated, and are then injected up and trapped.
45:45 Antiprotons that come in from ELENA are accumulated in a trap
45:49 and then also injected in a trap that sits just below the positrons.
45:53 Next, the two antiparticle clouds are gently merged.
45:57 This causes some of the antiprotons to capture a positron and form antihydrogen.
46:02 Now, antihydrogen is neutral,
46:05 which means that the Penning trap can no longer hold it.
46:07 So if nothing else was done, the antihydrogen atoms would form,
46:11 drift off, and within microseconds annihilate at one of the walls.
46:16 It would all be for nothing.
46:18 And this is exactly what happened with the earliest antihydrogen experiments.
46:22 They couldn't hold on to it.
46:24 Fortunately, there is a way to trap antihydrogen,
46:27 because it has a small magnetic moment.
46:30 So a second magnetic trap was engineered around the device,
46:34 which could capture the antihydrogen.
46:36 Unfortunately, that trap is pretty weak,
46:38 so most antihydrogen atoms escape and annihilate.
46:42 But a few stay.
46:43 And the idea then is simple.
46:45 Slowly weaken the magnetic field holding them,
46:48 and as the trap gets weaker and weaker, antiatoms start to escape.
46:52 And if gravity pulls antimatter down, like normal matter,
46:56 then more atoms should escape through the bottom than through the top.
47:00 So what did they find?
47:01 Does antimatter fall up or down?
47:04 They found that antimatter falls down.
47:07 So it rules out any exotic theories of antigravity.
47:11 They measured the gravitational acceleration as 75% of normal gravity,
47:16 plus minus 13%, plus minus 16%.
47:19 Which is possibly consistent with normal gravity,
47:22 but of course the error bars are huge.
47:25 And this is also why GBAR is so important.
47:27 Because their hope is to get the measurement accuracy down to 1%,
47:32 and ultimately to 1 in 100,000.
47:35 See, when you're doing a gravity experiment on atoms like this, you
47:39 want those atoms to be as still as possible before you drop them.
47:43 In other words, you want them to be as cold as possible.
47:47 Now, ALPHA-g can get really cold to about 0.5 Kelvin,
47:51 which is half a degree above absolute zero.
47:54 But GBAR wants to bring this way down to less than 10 micro-Kelvin,
47:58 that is 50,000 times colder.
48:02 The way they plan on doing this is actually not by making antihydrogen atoms,
48:07 but by making an antihydrogen ion, one antiproton and two positrons.
48:13 The hope is that once an antihydrogen atom has formed,
48:17 it runs into a second positronium atom and steals another positron.
48:21 At first, that might seem strange,
48:23 because now we're back to having a charged particle.
48:26 And as we learned, you can just drop
48:28 a charged particle and measure the effects of gravity.
48:31 But charged particles are actually much easier to trap and cool.
48:35 And we can use that.
48:37 Because now it can be held in a much stronger electromagnetic trap.
48:41 And once there, you can inject ultra-cold,
48:43 like 10 millikelvin, beryllium ions that have been laser-cooled.
48:48 The antihydrogen ion then bounces around and collides with these beryllium ions,
48:53 slowly transferring its kinetic energy to them and thus cooling down.
48:57 And they won't annihilate, because both particles are positively charged,
49:01 so they repel each other.
49:03 Then you keep cooling down the beryllium ions using more advanced techniques,
49:08 until you hit the micro-Kelvin range.
49:11 And this is ultimately how they hope
49:13 to reach a temperature of around 10 micro-Kelvin.
49:17 Now, with the antihydrogen ion as still as possible,
49:21 they shoot a laser pulse at it,
49:23 dislodging one of its positrons and resulting in a neutral antihydrogen atom.
49:29 And as a result, the electromagnetic trap can no longer hold it.
49:32 And so it falls.
49:34 Around 20 centimeters.
49:36 At that temperature and over that distance,
49:39 you can time the fall precisely enough
49:41 to measure the gravitational acceleration to about 1%.
49:45 So all of this, the particle accelerator making the positronium,
49:49 and then the hard way of cooling it,
49:51 all of it is just to watch a single antiatom fall 20 centimeters.
49:56 Because this process is the only known way to make antihydrogen ions.
50:01 And using those ions is the only way to get
50:04 antimatter cold enough to perform an accurate enough experiment.
50:08 Now, they haven't managed to do this yet.
50:10 So far, they've only made antihydrogen.
50:13 But if they can manage,
50:15 then it would be the most precise measurement of antimatter under gravity.
50:19 Although this is likely still years away.
50:23 Now, one thing that makes this research so tricky and also relatively
50:27 slow is that there is only one antimatter factory in the world.
50:31 And so the number of places that can study real antimatter is very limited.
50:36 But that might soon change, all thanks to another experiment at the factory.
50:42 The BASE experiment was built to measure the magnetic moment of the antiproton.
50:46 If CPT symmetry holds,
50:49 then it should be exactly equal and opposite to that of the proton.
50:53 But they kept running into a problem.
50:56 CERN has continuously ramping magnetic fields in the background.
50:59 Right.
51:00 Even though these fluctuations were tiny,
51:02 around 20,000 times weaker than the Earth's magnetic field,
51:05 at the precision BASE was working at, they hit a wall.
51:09 The only concept basically to overcome this problem
51:13 is to move the particles out of the accelerator.
51:17 So they built a Penning trap with its own power supply,
51:20 its own cooling system, and two storage holes for antiprotons.
51:24 So now they could fill those holes with antiprotons,
51:26 store them, and carry them to wherever they wanted.
51:30 They just created the world's first portable antimatter trap.
51:36 So of course I asked them a pressing scientific question.
51:40 Are you gonna make it look super futuristic?
51:42 Because it's got to be the most badass transport container ever made.
51:48 I just have this trap here in my office.
51:52 Maybe I can show it to you.
51:53 Oh, yes, please.
51:54 Oh...
51:55 This is one of these Penning traps.
51:56 And they are inside the superconducting magnet.
51:59 So the heavy part is basically the superconducting magnet.
52:03 But these are these trap electrodes.
52:05 And it works.
52:06 They have cracked the code of storing
52:08 the most volatile substance in the universe.
52:11 Their current record for storing antiprotons is 614 days.
52:16 That is, they can store antimatter, you know,
52:18 the stuff that annihilates as soon as it touches matter, for close to two years.
52:23 That is absurd.
52:25 This is this antiproton reservoir trap that stores
52:28 antiprotons for longer than one or two years.
52:32 That's awesome.
52:33 But here's what that means.
52:35 Because if you can store antimatter for years in a box,
52:39 and you can put the box on a truck, then why not ship it?
52:44 We can start distributing antiprotons
52:47 to ambitious experiments all around the planet.
52:50 And everyone who has a good idea what we
52:53 could do with these particles will get these particles.
52:57 I'm just imagining this map in my head
52:58 where you have the big antimatter factory,
53:01 and then it's gonna be sending antimatter all
53:03 over the world to all the top research institutions.
53:07 That's great, right?
53:08 It's awesome.
53:09 Fantastic solution.
53:10 Fantastic.
53:10 Yeah.
53:11 Yes, yes, yes.
53:13 And they've already started.
53:15 On the 24th of March, 2026, a crane lifted an 800-kilogram trap out
53:21 of the antimatter factory and loaded it onto a truck,
53:24 which then drove on a 10-kilometer loop around CERN.
53:28 And it was filled with 92 antiprotons.
53:33 So perhaps "Angels and Demons" wasn't that far off after all.
53:37 In the near future, there could be actual boxes
53:40 of antimatter that, at least in theory, could be stolen.
53:43 So does that also mean that they were right
53:46 about that one eighth of a gram of antimatter?
53:48 Well, we wanted to find out, so we tested it.
53:52 I mean, we simulated it.
53:54 This is the most supervillain call I've ever got.
53:57 (laughs)- I'm really getting into my villain arc here.
54:00 Okay, so let's find our poor target, Vatican City.
54:06 We've got an eighth of a gram, you know, selected right there, 0.125.
54:11 Who wants to do a countdown?
54:13 Three, two, one.
54:14 Let's go!
54:17 Let's go!
54:19 Oh my God.
54:20 Okay, so we've got a few levels of destruction here.
54:23 We've got the fireball.
54:25 This is just all instantly vaporized.
54:27 It's turned into pure plasma, which is insane.
54:31 Oh, St.
54:32 Peter's Basilica.
54:33 It's got a temperature of about 100 million degrees Celsius,
54:37 which is, you know, pretty chill.
54:39 You can see it released about 2.25 times 10 to the 13 joules,
54:45 or I guess about 22 trillion joules,
54:49 which is the equivalent of like 36% of the Hiroshima blast.
54:55 If we zoom out, this is the area of third degree burn, so your skin gets molten.
55:01 Bro, you're having way too much fun with this.
55:04 Can I ask this question?
55:05 Like, do we have an eighth of a gram of antimatter available for this?
55:09 Asking for a friend.
55:11 Can you really steal an eighth of a gram from CERN?
55:13 That's a good question.
55:15 Do you know how much antimatter you've made in total in this factory?
55:19 We make in the order of 10 to the 10 protons, antiprotons per year.
55:24 Now we can make an estimate.
55:26 This facility is around since 25 years.
55:29 So let's say this is 10 to the 11 protons.
55:34 A gram would be 10 to the 23.
55:39 So we are talking here of, well, I'm not very good at math but it's like...
55:45 A trillionth of a gram.
55:48 That means that to make one eighth of a gram of antimatter,
55:50 the factory would have to run for longer than the age of the universe.
55:55 In fact, if you took all the 10 billion antiprotons
55:57 they make in a year and annihilated them all at once,
56:01 you would produce enough energy to heat one
56:04 milliliter of water by about one degree Celsius.
56:09 I'd love to see Croatia, again, just for size and scale.
56:13 How much?
56:14 You tell me.
56:15 All right.
56:16 10 grams of antimatter.
56:17 Sure, let's do it.
56:19 Oh my God.
56:22 So while 10 grams of antimatter would destroy an entire city...
56:27 Bye bye hometown.
56:28 The amounts of antimatter they're making at CERN are in no way dangerous,
56:32 which is also part of the reason we had some fun with this simulation.
56:37 Because for the far foreseeable future,
56:39 it's just not realistic to talk about having macroscopic amounts of antimatter.
56:44 So if people want to play around with this, we'll put a link in the description.
56:49 Yeah, have fun.
56:51 Or if you'd rather get some antimatter yourself without having to rob CERN,
56:56 then I'll tell you how to get some.
56:58 Just go to your local supermarket and buy yourself this.
57:03 Some bananas.
57:05 That's because a banana contains trace
57:07 amounts of the radioactive isotope potassium-40.
57:10 And roughly every 75 minutes, one of these atoms decays and releases a positron.
57:16 Which means that if you wanted to match the antimatter factory's output,
57:19 in terms of antiparticles, you would need about a billion bananas.
57:27 Now that's a lot of bananas, and I don't recommend eating that many.
57:31 But the thing is, even if you never eat any bananas,
57:35 odds are there are some trace amounts of radioactive materials inside of you.
57:40 And some of those will produce antimatter.
57:43 One article estimates that the average
57:46 human makes around 180 positrons per hour.
57:49 And so there truly is no need to be scared of antimatter,
57:53 because you have been your own little antimatter factory all along.
58:01 Hey, just a few final things.
58:04 The first thing is I want to give a big shout out to Physics Girl,
58:07 who made an amazing video for the antimatter factory years ago.
58:11 And ever since I watched that video, I've always wanted to go.
58:14 So it's been a huge inspiration,
58:16 and I highly recommend you check out that video here.
58:19 The other thing is I want to give a quick shout out to all the people at CERN,
58:23 those who helped us with all the animations,
58:26 those who've hosted us and taken the time to explain their live work,
58:29 and everyone else, thank you so much.
58:32 And the third and final thank you is of course, as always, to you.
58:36 Thank you so much for watching, and I'm excited to see you at the next one.
58:48 AntiCasper, Casper, annihilate.
58:52 All right, that's it.