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Do black holes have magnetic fields? · Daniel and Kelly’s Extraordinary Universe

• 0:07
  Speaker 1: Hey, Danie, what do you think makes black holes so interesting?
• 0:11
  Speaker 2: You know, I think the mystery, the finality of it,
• 0:14
  Speaker 2: the weirdness of it.
• 0:16
  Speaker 1: For sure, they're like a magnet for fascination.
• 0:21
  Speaker 2: They absolutely are for curiosity, for investigation, for dedication.
• 0:27
  Speaker 1: And it's not just physicists. Everyone seems to have questions
• 0:30
  Speaker 1: about black holes.
• 0:31
  Speaker 2: Yeah, they seem to be sort of mentally magnetic.
• 0:36
  Speaker 1: So black holes attract matter and also questions.
• 0:41
  Speaker 2: They definitely attract questions. They seem to repel understanding.
• 0:45
  Speaker 1: Or they just repel physicists.
• 0:48
  Speaker 2: I'm pretty sure they'd be happy to suck me right in.
• 0:51
  Speaker 1: I don't think I want to go down that rabbit hole.
• 1:09
  Speaker 1: Hi am Hora May Cartoons, an author of Oliver's Great
• 1:12
  Speaker 1: Big Universe.
• 1:13
  Speaker 2: Hi, I'm Daniel. I'm a particle physicist and a professor
• 1:16
  Speaker 2: at UC Irvine, and I desperately want to know what's
• 1:20
  Speaker 2: inside those black.
• 1:21
  Speaker 1: Holes, if there is even an inside. Right do we
• 1:24
  Speaker 1: know that they have an inside?
• 1:26
  Speaker 2: We don't really know anything beyond the event horizon at all.
• 1:30
  Speaker 2: In some sense, the interior of a black hole could
• 1:33
  Speaker 2: be like another universe.
• 1:35
  Speaker 1: Whoa like We could be living inside of a black
• 1:38
  Speaker 1: hole right now, is that possible.
• 1:42
  Speaker 2: I think that gives me a mental black hole even
• 1:43
  Speaker 2: thinking about it.
• 1:47
  Speaker 1: I suckered you write in. But anyways, welcome to our
• 1:49
  Speaker 1: podcast Daniel and Jorge Explain the Universe, a production of iHeartRadio.
• 1:53
  Speaker 2: In which we try our best not to give you
• 1:55
  Speaker 2: a headache while we contemplate the deepest secrets of the universe.
• 2:00
  Speaker 2: Want to understand everything that's out there, from the tiniest
• 2:02
  Speaker 2: little bits to the hugest swirling black holes and everything
• 2:07
  Speaker 2: in between, because we think that it's possible somehow to
• 2:10
  Speaker 2: make sense of it all, to understand it, to predict it,
• 2:13
  Speaker 2: and to explain all of it to you.
• 2:15
  Speaker 1: Yeah, that's right. We try to be the advil or
• 2:17
  Speaker 1: tile and all to your understanding of the universe, not
• 2:20
  Speaker 1: give you a headache about how amazing things are, but
• 2:22
  Speaker 1: rather try to ease the pain of trying to wrap
• 2:26
  Speaker 1: your mind around this amazing costmoves we live in. I
• 2:29
  Speaker 1: think it was as your prescription for physics.
• 2:34
  Speaker 2: Well, everybody out there is going to need like another
• 2:36
  Speaker 2: kind of health insurance now physics health insurance.
• 2:40
  Speaker 1: The physicists have special health insurance for you know, headaches
• 2:44
  Speaker 1: and mind bending.
• 2:46
  Speaker 2: We're going to help you cover the cost of understanding
• 2:48
  Speaker 2: the universe, because while physics has made lots of progress
• 2:52
  Speaker 2: in understanding the way the universe works, there are still
• 2:55
  Speaker 2: huge gaps in our knowledge. In fact, we're pretty sure
• 2:59
  Speaker 2: there's more that we own understand than that we do,
• 3:02
  Speaker 2: and a lot of those mysteries might have answers waiting
• 3:05
  Speaker 2: for us beyond the curtain of the event horizon.
• 3:08
  Speaker 1: Yeah, as we've talked about, we only know about five
• 3:11
  Speaker 1: percent of the whole universe. The rest, the other ninety
• 3:14
  Speaker 1: five percent is a complete mystery. And even within the
• 3:16
  Speaker 1: five percent there we think we know, there are still
• 3:19
  Speaker 1: huge holes in our understanding of how things work and
• 3:23
  Speaker 1: what can happen out there in the universe.
• 3:25
  Speaker 2: The best way to unravel some of the open mysteries
• 3:27
  Speaker 2: is to embrace the unknown, is to dive into our
• 3:31
  Speaker 2: ignorance and try to reveal something new about the universe.
• 3:35
  Speaker 2: Often this happens at the extreme points of the universe,
• 3:38
  Speaker 2: places where things are super duper hot, are super duper dense,
• 3:42
  Speaker 2: or super duper crazy, because it's that those places that
• 3:45
  Speaker 2: our understanding breaks down. That's one reason why black holes
• 3:49
  Speaker 2: are so attractive to physicists, because they are where our
• 3:53
  Speaker 2: current theories have to break.
• 3:55
  Speaker 1: Yeah, it seems like there's no place in the universe
• 3:57
  Speaker 1: that is more extreme or mysterious and a black hole.
• 4:01
  Speaker 1: We have so many questions about that. Everyone has questions
• 4:03
  Speaker 1: about it. It seems that it attracts not just mass
• 4:06
  Speaker 1: and energy, but also curiosity.
• 4:08
  Speaker 2: It does absolutely. I don't know if it sucks in curiosity,
• 4:11
  Speaker 2: or it's radiating curiosity, or how the whole curiosity field works.
• 4:15
  Speaker 1: Talking talking radiation of curiosity exactly.
• 4:19
  Speaker 2: Maybe it's consuming anti curiosity while radiating curiosity.
• 4:23
  Speaker 1: He knows anti curiosity. Oh, that's an interesting concept, But
• 4:27
  Speaker 1: what is that?
• 4:28
  Speaker 2: I don't know. That's what we're trying to generate on
• 4:29
  Speaker 2: this podcast. We're trying to satisfy everybody's curiosity or are
• 4:33
  Speaker 2: we just trying to stoke it. I'm not even sure anymore.
• 4:36
  Speaker 1: It sounds like you're trying to annihilate people curiosity.
• 4:41
  Speaker 2: No, I guess we're trying to generate anti confusion particles.
• 4:44
  Speaker 2: How about that?
• 4:44
  Speaker 1: Oh, there you go, rock Ons, get it. Tino's exactly
• 4:50
  Speaker 1: the AHA particles. That's what we're after.
• 4:54
  Speaker 2: Yeah, I want to be one with the AHA field.
• 4:57
  Speaker 2: But there are still very basic questions about how black
• 5:00
  Speaker 2: holes work, what it means to be near a black hole,
• 5:02
  Speaker 2: what you would experience, what you might measure with your
• 5:04
  Speaker 2: devices near a black hole. We've talked about the massive
• 5:08
  Speaker 2: black holes, we talked about the charge of black holes,
• 5:10
  Speaker 2: we talked about the spin of black holes. But there
• 5:13
  Speaker 2: are still even more basic things we can think about
• 5:15
  Speaker 2: when it comes to black holes.
• 5:17
  Speaker 1: So today on the podcast, we'll be tackling the question
• 5:25
  Speaker 1: do black holes have magnetic fields?
• 5:28
  Speaker 2: Like?
• 5:29
  Speaker 1: Are they attractive or repulsive? Do they have raised or not?
• 5:34
  Speaker 2: Can you use black holes to find lost wedding rings
• 5:37
  Speaker 2: on the beach? I knew there was a practical application
• 5:39
  Speaker 2: of my research somewhere.
• 5:41
  Speaker 1: Could you use it to detect your wedding ring on
• 5:43
  Speaker 1: the beach when in it just swallow up the whole beach?
• 5:47
  Speaker 2: Then you'd have a good excuse for why you lost
• 5:49
  Speaker 2: your wedding ring. Look, there was a black hole on
• 5:52
  Speaker 2: the beach.
• 5:53
  Speaker 1: Yeah, and you would technically know where it is. It's
• 5:55
  Speaker 1: inside the black hole. You just you know you can't
• 5:58
  Speaker 1: get it.
• 5:59
  Speaker 2: Ever, Yeah, exactly. No number of explainingons is going to
• 6:03
  Speaker 2: get you out of that jam.
• 6:04
  Speaker 1: Yeah, But yeah, it's an interesting question. Do black holes
• 6:07
  Speaker 1: have magnetic field? And I know, we've did a whole
• 6:10
  Speaker 1: episode on whether black holes have a charge, right, Yeah,
• 6:14
  Speaker 1: and so this is different. This is more about the
• 6:16
  Speaker 1: magnetic field.
• 6:17
  Speaker 2: Yeah, we did one on charge, we did another one
• 6:20
  Speaker 2: on spin. There's not that much stuff you can actually
• 6:22
  Speaker 2: know about black holes, and we know so little, so
• 6:25
  Speaker 2: I'm always excited to talk more about it.
• 6:27
  Speaker 1: Then we do a whole episode on the hairiness of
• 6:29
  Speaker 1: a black hole.
• 6:31
  Speaker 2: That's true, their lack of hairiness actually their smooth shavenness.
• 6:36
  Speaker 1: Yeah. Well, this is an interesting question, and so as usual,
• 6:40
  Speaker 1: we were wondering how many people out there had thought
• 6:43
  Speaker 1: about whether black holes have magnetic fields, and if they do,
• 6:47
  Speaker 1: what do they look like or feel like.
• 6:49
  Speaker 3: I think it's possible that they do, I think if
• 6:53
  Speaker 3: I'm not too sure exactly after rationalets, but somehow I
• 6:57
  Speaker 3: feel like it might be possible for black holes to
• 6:59
  Speaker 3: have mynetic fields.
• 7:00
  Speaker 4: I think they do, if only from the spiraling matter
• 7:03
  Speaker 4: that's been consumed by the black hole. Whether or not
• 7:07
  Speaker 4: they are magnetic in their core, whatever their core is,
• 7:10
  Speaker 4: if you can have a call in a black hole,
• 7:12
  Speaker 4: I don't know, but by virtue of the whole of
• 7:14
  Speaker 4: the object that's whorly yes.
• 7:17
  Speaker 5: I do not believe so only because I do not
• 7:20
  Speaker 5: believe there are any charged particles within a black hole. However,
• 7:23
  Speaker 5: since we do see jets coming from black holes at times,
• 7:25
  Speaker 5: that could be totally wrong about that.
• 7:27
  Speaker 1: I don't really know, but if I had to guess,
• 7:30
  Speaker 1: I think they would like.
• 7:31
  Speaker 2: Something to do with the hawking radiation being magnetized somehow, or.
• 7:36
  Speaker 6: So the black hole itself beyond the event horizon. I
• 7:40
  Speaker 6: don't think we can know that, but the area around
• 7:43
  Speaker 6: the black hole where the Acresian disk is probably can
• 7:45
  Speaker 6: have a magnetic field.
• 7:47
  Speaker 2: Black Holes have mass, and they have spin, and I
• 7:51
  Speaker 2: believe they have a charge.
• 7:52
  Speaker 6: So if something has a charge, it should also have
• 7:54
  Speaker 6: a magnetic field, probably a little squirrely with the amount.
• 7:59
  Speaker 2: Of gravitational force is going on, but going with yes.
• 8:03
  Speaker 7: Yes, I'm pretty sure black holes have magnetic fields because
• 8:05
  Speaker 7: whenever a particle that's charged enters it, the electric charge
• 8:08
  Speaker 7: is conserved. So I guess a black hole would need
• 8:10
  Speaker 7: to have that magnetic field that the particle had.
• 8:13
  Speaker 1: I have no idea that.
• 8:15
  Speaker 7: As a wild guest, I would say, yes, they have
• 8:18
  Speaker 7: probably vacuumed app some magnetic vibes along the way.
• 8:22
  Speaker 2: Black holes do have magnetic fields.
• 8:24
  Speaker 3: I'm pretty sure that the Beatles wrote a song about it,
• 8:27
  Speaker 3: Magnetic fields forever.
• 8:30
  Speaker 6: If a black hole is churning around, does it create
• 8:32
  Speaker 6: a magnetic field? Is there a north pole to a
• 8:35
  Speaker 6: black hole? I wonder if magnetism can escape gravity or
• 8:40
  Speaker 6: is immune to it.
• 8:42
  Speaker 2: I think magnetize are neutron stars with a magnetic charge.
• 8:45
  Speaker 2: I'm not sure about a black hole. Maybe if it's
• 8:48
  Speaker 2: spinning and has an electric charge.
• 8:50
  Speaker 5: I think that if a black hole a bunch of
• 8:53
  Speaker 5: large stuff with a magnetic field, and the black hole
• 8:55
  Speaker 5: would get a magnetic field.
• 8:58
  Speaker 8: I'm gonna say yes because this one out of three
• 9:00
  Speaker 8: things that that black hole present so that we can measure.
• 9:03
  Speaker 8: But I forget one of them. So there are spin, there, mass,
• 9:07
  Speaker 8: and electromagnetic force. So I'm gonna say yes.
• 9:10
  Speaker 1: All right. Interesting answers from a lot of magnetic people.
• 9:16
  Speaker 2: Yeah, you could tell a lot of people had not
• 9:17
  Speaker 2: thought about this question at all. They seem to sort
• 9:20
  Speaker 2: of come up with their answers on the fly.
• 9:22
  Speaker 1: Yeah, it's kind of a polarizing question.
• 9:26
  Speaker 2: People either retracted or repelled by it.
• 9:30
  Speaker 1: Yeah, Well, it seemed to attract definitely a lot of
• 9:32
  Speaker 1: ideas about what's going on in the black hole, and
• 9:35
  Speaker 1: so let's dive right into it. Daniel take us through
• 9:38
  Speaker 1: the basics of black holes and how they relate to electromagnetism.
• 9:42
  Speaker 2: So fundamentally, we don't really know what black holes are
• 9:45
  Speaker 2: in our actual universe, like the physical things that are
• 9:48
  Speaker 2: at the center of the galaxy, or they have really
• 9:51
  Speaker 2: dense stuff orbiting them really closely. We're not really sure
• 9:54
  Speaker 2: what those things are, but we do have a concept
• 9:58
  Speaker 2: in our theory general relativity dicks a kind of black
• 10:01
  Speaker 2: hole that we know. Again, general relativity can't be right,
• 10:04
  Speaker 2: so this theoretical object can't actually align with what's out
• 10:07
  Speaker 2: there in the universe, but it gives us something to
• 10:09
  Speaker 2: dig into, something that play with. And because general relativity
• 10:13
  Speaker 2: tells us that gravity is not a force between objects
• 10:16
  Speaker 2: the way Newton described it, but instead a curvature of
• 10:19
  Speaker 2: space time, there's something weird that can happen when you
• 10:22
  Speaker 2: get enough mass, enough energy density actually together in one place,
• 10:27
  Speaker 2: which is that space can curve so much that the
• 10:30
  Speaker 2: inside is essentially cut off from the outside. There's a
• 10:33
  Speaker 2: place beyond which space is curved so that it only
• 10:36
  Speaker 2: points towards the center of the black hole, meaning any
• 10:40
  Speaker 2: object that falls past, that event horizon will always end
• 10:44
  Speaker 2: up at the center of the black hole. And so
• 10:46
  Speaker 2: this is the basic concept of a black hole, sort
• 10:49
  Speaker 2: of extreme space time curvature that generates this event horizon
• 10:54
  Speaker 2: past which nothing can escape.
• 10:55
  Speaker 1: Right, right, because I feel like that's always one of
• 10:57
  Speaker 1: the carriats we have to point out is that the
• 11:00
  Speaker 1: bending of space time, right, it's not just sort of space,
• 11:02
  Speaker 1: it's also sort of like what happens in the future.
• 11:05
  Speaker 2: There are definitely time related effects. Also, mass bends space
• 11:09
  Speaker 2: and creates this event horizon, it also bends time. So
• 11:13
  Speaker 2: you are near a black hole, for example, a distant observer,
• 11:16
  Speaker 2: we'll see your clock go more slowly, and near black holes,
• 11:19
  Speaker 2: space and time are very confusing, and in fact, the
• 11:22
  Speaker 2: whole concept of space time is easier to understand in
• 11:25
  Speaker 2: special relativity when you have flat space. In general relativity,
• 11:29
  Speaker 2: which direction is space and which direction is time becomes
• 11:31
  Speaker 2: very very confusing, and in some cases it's not even clear.
• 11:35
  Speaker 1: And so, as you said, it's something that physics predicts
• 11:40
  Speaker 1: is happening out there in the universe because we see
• 11:42
  Speaker 1: around us and it seems like, you know, the Sun
• 11:44
  Speaker 1: is bending space around it, the Earth is bending space
• 11:46
  Speaker 1: around and we're bending space around us. But if you
• 11:49
  Speaker 1: take it to an extreme, it predicts something called a
• 11:51
  Speaker 1: black hole.
• 11:52
  Speaker 2: Yeah, and a lot of people imagine a black hole
• 11:55
  Speaker 2: in a sort of Newtonian way. They think, oh, gravity
• 11:58
  Speaker 2: is so strong that you have to go faster than
• 12:01
  Speaker 2: the speed of light in order to escape it. But
• 12:04
  Speaker 2: it's not a question of forces, it's not a question
• 12:06
  Speaker 2: of a velocity. It's not a Newtonian picture at all.
• 12:10
  Speaker 2: It really tells you that the story of how gravity
• 12:12
  Speaker 2: works is very, very different. That you're literally trapped inside
• 12:15
  Speaker 2: this event horizon. No amount of velocity, no force can
• 12:19
  Speaker 2: ever escape it because the shape of space itself has changed.
• 12:23
  Speaker 2: And so if you imagine space is this like emptiness
• 12:26
  Speaker 2: in which things float, then you need a new idea.
• 12:29
  Speaker 2: General relativity tells us we could describe it as this
• 12:31
  Speaker 2: sort of stuff with curvature to it, that we're moving
• 12:35
  Speaker 2: through that curvature, and that curvature is not sitting inside
• 12:38
  Speaker 2: some like deeper, larger space that you might be tempted
• 12:41
  Speaker 2: to imagine. That's all there is, and we are trapped
• 12:44
  Speaker 2: inside of it, and there's nothing on the outside of
• 12:46
  Speaker 2: it as far as we.
• 12:47
  Speaker 1: Know, right, right, and as usual we also have to
• 12:50
  Speaker 1: give the cavit that black holds are technically theoretical, right, Like,
• 12:54
  Speaker 1: we've seen things that sort of behave like black hold
• 12:57
  Speaker 1: but we haven't sort of been in front of one
• 13:00
  Speaker 1: or touched it, right.
• 13:01
  Speaker 2: That's right. And what we're describing is a prediction of
• 13:04
  Speaker 2: general relativity, which we know to be very accurate in
• 13:07
  Speaker 2: most circumstances, except we expect it to break down when
• 13:11
  Speaker 2: things get very very intense and very very small. And so,
• 13:15
  Speaker 2: for example, general relativity predicts that at the heart of
• 13:18
  Speaker 2: one of these black holes is a singularity, a point
• 13:21
  Speaker 2: of infinite density. This runaway gravity just goes on forever
• 13:24
  Speaker 2: and you get infinite curvature at the heart of the
• 13:27
  Speaker 2: black hole. But we don't think that that's really happening
• 13:30
  Speaker 2: because we know that that's in conflict with quantum mechanics.
• 13:32
  Speaker 2: And so real black holes, if they exist out there
• 13:35
  Speaker 2: in the universe, can't align perfectly with this theoretical description
• 13:39
  Speaker 2: of a general relativity black hole. There has to be
• 13:41
  Speaker 2: some quantum fuzziness to it, some other version of a
• 13:44
  Speaker 2: black hole. And we talked recently on the podcast how
• 13:47
  Speaker 2: quantum black holes probably radiate. They're not perfectly black due
• 13:51
  Speaker 2: to Hawking radiation, and there must be other changes we
• 13:54
  Speaker 2: need to make from this general relativity picture of a
• 13:56
  Speaker 2: black hole to a realistic quantum gravity black hole that
• 13:59
  Speaker 2: we don't even know how to describe. And you're right
• 14:02
  Speaker 2: that the things we've seen out there in the universe,
• 14:05
  Speaker 2: at the heart of our galaxy, etc. We're not even
• 14:07
  Speaker 2: sure if they actually are black holes because we've not
• 14:10
  Speaker 2: technically observed an event horizon. All we've seen is that
• 14:14
  Speaker 2: there are very dense objects, very massive, very small, very compact,
• 14:19
  Speaker 2: and so we suspect that they are black holes, but
• 14:21
  Speaker 2: they could be something else. These days, there are quantum
• 14:24
  Speaker 2: gravity inspired ideas for other things that could fit the data.
• 14:29
  Speaker 2: Fuzzballs or dark stars, etc. Yeah, all kinds of fun names.
• 14:33
  Speaker 1: I wonder if we should maybe start calling black holes
• 14:35
  Speaker 1: and not black holes then maybe.
• 14:38
  Speaker 2: Or maybe just black holes with a question mark black
• 14:40
  Speaker 2: holes really dark objects rdos.
• 14:45
  Speaker 1: All right, So then a big concept in a black
• 14:48
  Speaker 1: hole is this idea of an event horizon. Now is
• 14:51
  Speaker 1: the idea of an event horizon also dependent on relativity
• 14:55
  Speaker 1: and quantum mechanics playing nicely with each other, or does
• 14:59
  Speaker 1: relativity only break down at the center of a black hole? Like,
• 15:03
  Speaker 1: is the edge of a black holes safe to talk about?
• 15:08
  Speaker 2: The edge of a black hole is really only something
• 15:10
  Speaker 2: we can talk about in general relativity. We don't know
• 15:12
  Speaker 2: how quantum mechanics will modify that. It might make it
• 15:15
  Speaker 2: so that there are no event horizons. These buzzballs, for example,
• 15:19
  Speaker 2: compact states of strings do not have event horizons at all,
• 15:23
  Speaker 2: So it could be that there are no event horizons
• 15:25
  Speaker 2: in the universe. So if we want to talk about this,
• 15:28
  Speaker 2: really the only thing we can do is talk about
• 15:29
  Speaker 2: what general relativity predicts, even though we're not exactly sure
• 15:33
  Speaker 2: it's real.
• 15:35
  Speaker 1: So then how do you define the event horizon?
• 15:37
  Speaker 2: Then? Well, in general relativity, the event horizon is the
• 15:40
  Speaker 2: point past which no information can escape, and that's something
• 15:43
  Speaker 2: we can calculate in general relativity and depends on the
• 15:46
  Speaker 2: mass of the object, also whether it's spinning, whether it
• 15:49
  Speaker 2: has charged these kinds of things.
• 15:52
  Speaker 1: And it's kind of a very special point in a
• 15:55
  Speaker 1: black hole because that's the point at which not even information.
• 15:58
  Speaker 2: Can escape, right, Yeah, that's right.
• 16:00
  Speaker 1: So the sort of limits of the things we can
• 16:02
  Speaker 1: know about the black hole.
• 16:04
  Speaker 2: Yeah, you can't know anything that's going on inside the
• 16:07
  Speaker 2: black hole, but you can measure some things about the
• 16:10
  Speaker 2: black hole, like we know, for example, obviously you can
• 16:12
  Speaker 2: measure the black hole's mass. You can measure its gravitational
• 16:15
  Speaker 2: effects on things nearby. If you fly near a black hole,
• 16:18
  Speaker 2: you're going to be drawn towards it because space is curved,
• 16:22
  Speaker 2: So the effect of the black hole exists outside the
• 16:25
  Speaker 2: event horizon. You can sort of think of it as
• 16:27
  Speaker 2: the event horizon itself having a property. The event horizon
• 16:31
  Speaker 2: is there, it summarizes all the stuff that's inside of it.
• 16:34
  Speaker 2: The mass of the event horizon or the black hole
• 16:36
  Speaker 2: itself affects space outside the event horizon. So you can
• 16:39
  Speaker 2: definitely know that about the black hole, and you can
• 16:41
  Speaker 2: know a couple of other details as well.
• 16:44
  Speaker 1: Like the spin and also the charge of a black hole.
• 16:47
  Speaker 2: Right, Yeah, that's right. Those are the three things that
• 16:50
  Speaker 2: general relativity says we can know about the black hole.
• 16:54
  Speaker 2: That a black hole can also be spinning, right, Things
• 16:56
  Speaker 2: that fall into a black hole if they have angler
• 16:59
  Speaker 2: momentum to keep having angular momentum, because in our universe,
• 17:02
  Speaker 2: angular momentum is conserved. We're pretty sure same thing with
• 17:06
  Speaker 2: electric charge. The universe strictly preserves electric charge. We've never
• 17:10
  Speaker 2: seen that violated. You can create plus and minus particles together,
• 17:14
  Speaker 2: but the overall charge of the universe has to be
• 17:16
  Speaker 2: the same. And so if you drop an electron into
• 17:19
  Speaker 2: a black hole, then the black hole has to have
• 17:22
  Speaker 2: that charge because it can't just disappear from the universe.
• 17:25
  Speaker 2: So mass, spin, and charge are the things you can
• 17:28
  Speaker 2: know about a black hole from the outside. You can't
• 17:31
  Speaker 2: know like the arrangement of charges or masses or spins
• 17:34
  Speaker 2: or whatever inside the event horizon, but you don't have
• 17:37
  Speaker 2: to in order to know the total mass or the
• 17:39
  Speaker 2: total charge or the total spin from the outside.
• 17:42
  Speaker 1: Can you tell if that black hole has a headache
• 17:44
  Speaker 1: or something?
• 17:47
  Speaker 2: Do black holes wear mood rings? I wish they did?
• 17:50
  Speaker 2: Always black?
• 17:50
  Speaker 1: Does that mean do they wear engagement rings? Well, you
• 17:55
  Speaker 1: said charge, and I'm wondering. You know, that's the electromagnetic charge,
• 17:59
  Speaker 1: but we also talked about it in this podcast. But
• 18:01
  Speaker 1: other kinds of charge in the universe, from the weak
• 18:04
  Speaker 1: fours and the strong force. Can you know those other
• 18:07
  Speaker 1: charges about a black hole? Can you know the color
• 18:10
  Speaker 1: of a black hole?
• 18:11
  Speaker 2: The color charges are really fun and tricky concept. It's
• 18:14
  Speaker 2: not something we really understand very well because objects that
• 18:17
  Speaker 2: have color don't ever exist in the universe. We only
• 18:20
  Speaker 2: see neutral things, like things that have color, like quarks
• 18:23
  Speaker 2: are always bound together into neutral states, something with the
• 18:26
  Speaker 2: opposite color or the other two complementary colors, so they
• 18:30
  Speaker 2: balance out because there's so much energy in the strong force,
• 18:33
  Speaker 2: so things can't have their own color charge. You might
• 18:37
  Speaker 2: want to imagine, like what happens if you have a
• 18:39
  Speaker 2: quark anti quark pair and they're bound together, but one
• 18:42
  Speaker 2: of them falls into the black hole. And now you're
• 18:44
  Speaker 2: doing quantum gravity, because we're talking about bound states of quarks,
• 18:48
  Speaker 2: and one of them falls into the black hole and
• 18:49
  Speaker 2: the other one doesn't. We don't know the answers to
• 18:52
  Speaker 2: those questions because we don't have a theory of quantum gravity.
• 18:55
  Speaker 1: But is it possible then maybe they also conserve those
• 18:59
  Speaker 1: kinds of charges, and you would have to add that
• 19:01
  Speaker 1: to the list of things you can know about a
• 19:03
  Speaker 1: black hole.
• 19:03
  Speaker 2: It is possible, And it's also possible that there are
• 19:06
  Speaker 2: other kinds of charges in the universe we've never even discovered,
• 19:09
  Speaker 2: like dark matter could have all sorts of other forces.
• 19:12
  Speaker 2: There could be like a dark version of electromagnetism with
• 19:15
  Speaker 2: dark photons and dark charges, and black holes could have
• 19:18
  Speaker 2: those dark charges as well.
• 19:20
  Speaker 1: Wait, were you saying black holes could have a hidden
• 19:22
  Speaker 1: charge like a hidden fee?
• 19:26
  Speaker 2: Exactly? Check your statements, people.
• 19:28
  Speaker 1: When you buy a black hole, read the small print
• 19:30
  Speaker 1: before you go into a black hole. All right, So
• 19:33
  Speaker 1: then that's you know, we can tell it it has
• 19:36
  Speaker 1: a gravitational field and an electric field. And now let's
• 19:38
  Speaker 1: talk about a magnetic field of a black hole. What
• 19:42
  Speaker 1: exactly is a magnetic field?
• 19:43
  Speaker 2: Magnetic fields are really weird and awesome because they have
• 19:47
  Speaker 2: lots of really interesting symmetries, symmetries that exist and also
• 19:50
  Speaker 2: symmetries that are broken. Like in a lot of ways,
• 19:53
  Speaker 2: the magnetic field is a perfect sister to the electric field,
• 19:58
  Speaker 2: like light, for example, is a between electric fields and
• 20:01
  Speaker 2: magnetic field. It's slashing perfectly back and forth between electric
• 20:05
  Speaker 2: fields and magnetic fields and back. It really tells us
• 20:08
  Speaker 2: that the distinction we make between electric fields and magnetic
• 20:11
  Speaker 2: fields is a little bit arbitrary. It's just sort of
• 20:13
  Speaker 2: like a historical thing. We drew a dotted line between
• 20:16
  Speaker 2: these two things that are really part of a larger hole.
• 20:20
  Speaker 2: But there also are important differences between electric fields and
• 20:23
  Speaker 2: magnetic fields. For example, we have electric charges in the universe,
• 20:26
  Speaker 2: but we don't have magnetic charges. Like an electron has
• 20:30
  Speaker 2: a negative charge. You can just create a charged object
• 20:33
  Speaker 2: by putting an electron on it, right, you can't do
• 20:35
  Speaker 2: that with a magnetic field. There's nothing with a magnetic charge.
• 20:38
  Speaker 2: If it existed, this would be called a magnetic monopole.
• 20:41
  Speaker 2: It'd be like something with just a north or something
• 20:44
  Speaker 2: with just a south. We've never seen one in the universe.
• 20:47
  Speaker 2: Physicists don't know why. They think maybe they do exist
• 20:49
  Speaker 2: out there, or used to exist in the early universe.
• 20:52
  Speaker 2: But you can't make a magnetic field the same way
• 20:54
  Speaker 2: you make an electric field by just adding a magnetic
• 20:57
  Speaker 2: charge to something.
• 20:59
  Speaker 1: Well, maybe take a step back here, because you know,
• 21:02
  Speaker 1: like I'm wondering, how do you even define what a
• 21:04
  Speaker 1: magnetic field is. You know, like a gravitational field tells
• 21:08
  Speaker 1: me how much a planet, for example, is pulling on
• 21:10
  Speaker 1: me at any point in space, or an electric field
• 21:13
  Speaker 1: tells me how much you know, an electron is repelling
• 21:16
  Speaker 1: or pushing me or attracting me at any point in space.
• 21:19
  Speaker 1: What does a magnetic field tell you?
• 21:21
  Speaker 2: Yeah, great question. If they were magnetic monopoles, then they
• 21:25
  Speaker 2: would be affected by magnetic fields. The same way that
• 21:28
  Speaker 2: electrical charges are affected by electric fields. They would be
• 21:32
  Speaker 2: accelerated in one way or another. But those don't exist,
• 21:36
  Speaker 2: so we can't use that to define magnetic fields.
• 21:39
  Speaker 1: What do you mean, like when you talk about monopole,
• 21:42
  Speaker 1: you mean like like an a maact that you have
• 21:43
  Speaker 1: a north in the south.
• 21:44
  Speaker 2: Right in the magnets that we have in our universe,
• 21:47
  Speaker 2: we have a north in the south. Those are dipole
• 21:49
  Speaker 2: magnets that create a dipole magnetic field. There's a pair
• 21:53
  Speaker 2: of a North in the south.
• 21:54
  Speaker 1: So are you saying, like, if you had a North
• 21:56
  Speaker 1: in front of me and I'm the south, it would
• 21:58
  Speaker 1: tell me how much I'm attracted to the north repel?
• 22:01
  Speaker 2: Yeah, exactly. If you have a huge magnet makes a
• 22:02
  Speaker 2: magnetic field, and then if you put a North in
• 22:05
  Speaker 2: that field, it would get pushed or pulled in one direction,
• 22:08
  Speaker 2: and by the strength of that push or pull, you
• 22:10
  Speaker 2: could measure the magnetic field.
• 22:12
  Speaker 1: So there is some sort of charge, Yeah, exactly, Like
• 22:14
  Speaker 1: what would determine how much of that push and pool?
• 22:17
  Speaker 1: I feel?
• 22:17
  Speaker 2: Well, the north and south are like the plus and minus. Right,
• 22:21
  Speaker 2: North and south for a magnetic field are plus and
• 22:23
  Speaker 2: minus for electric charges.
• 22:24
  Speaker 1: And I can have like more of it or less fit.
• 22:26
  Speaker 2: Yeah, exactly, you've got to bigger magnets or smaller magnets.
• 22:30
  Speaker 2: You've got to more norths and more souths. We've never
• 22:33
  Speaker 2: seen a north on its own or a south on
• 22:35
  Speaker 2: its own the way we have for electric charges. But
• 22:37
  Speaker 2: in principle they could exist. Nothing in physics says that
• 22:40
  Speaker 2: they can't. But we've only ever seen them paired together.
• 22:44
  Speaker 1: I mean, like, if something has a north, it also
• 22:46
  Speaker 1: has a south.
• 22:47
  Speaker 2: Yeah, and that's because those magnetic fields are actually made
• 22:50
  Speaker 2: by electric charges. See, there's a very close connection between
• 22:54
  Speaker 2: electricity and magnetism because if you take an electric charge,
• 22:57
  Speaker 2: like an electron, and you wiz it around them, it
• 23:00
  Speaker 2: makes a magnetic field. Any charge in motion, any charge
• 23:04
  Speaker 2: with velocity, is going to make a magnetic field. And
• 23:07
  Speaker 2: so every magnetic field that we ever created is actually
• 23:10
  Speaker 2: made by moving electric charges.
• 23:13
  Speaker 1: So if it's made by electric charges, it's made by
• 23:15
  Speaker 1: the electric field. So why do we even call it
• 23:18
  Speaker 1: its own field.
• 23:18
  Speaker 2: Well, because it's made by electric charges doesn't mean it's
• 23:21
  Speaker 2: an electric field, right, Yeah, we could just call this electromagnetism.
• 23:24
  Speaker 2: You might be saying, Hey, the distinction between these two things.
• 23:27
  Speaker 2: Seems arbitrary. Yes, it's totally arbitrary and historical. Because we
• 23:31
  Speaker 2: discovered magnets and we discovered lightning. We call them two
• 23:33
  Speaker 2: separate things. We build two theories, and then boom, one
• 23:36
  Speaker 2: day a brilliant Scottish dude realized they are actually two
• 23:39
  Speaker 2: parts of the same thing. Now we call them electromagnetism.
• 23:42
  Speaker 2: And you might say, let's just call it all electromagnetic fields. Cool,
• 23:45
  Speaker 2: we can do that, but we do notice that there
• 23:47
  Speaker 2: are two different charges that are described by this field,
• 23:50
  Speaker 2: electric charges and magnetic charges, and only one seems to
• 23:53
  Speaker 2: exist in the universe.
• 23:55
  Speaker 1: M all right, So it's deeply connected to electricity, and
• 24:01
  Speaker 1: if some things just seem to have it or not, right,
• 24:04
  Speaker 1: things would charge seem to have it or not.
• 24:06
  Speaker 2: Yeah. So every magnet we've ever seen in the universe
• 24:09
  Speaker 2: is either a tiny little object that has quantum spin,
• 24:13
  Speaker 2: like an electron has quantum spin, and that spin combined
• 24:16
  Speaker 2: with its charge, makes it a tiny little magnet. But
• 24:19
  Speaker 2: because it's spinning, it makes two magnets. It makes a
• 24:21
  Speaker 2: north and a south, so it's a little dipole magnet.
• 24:25
  Speaker 2: Or you can have current like motion of electrons through
• 24:27
  Speaker 2: a wire that makes a dipole magnet. So every magnetic
• 24:31
  Speaker 2: field we've ever seen is made either by tiny little
• 24:34
  Speaker 2: quantum particles having their own little magnetic fields. That's, for example,
• 24:37
  Speaker 2: why your refrigerator magnet has a magnetic field. Has all
• 24:40
  Speaker 2: these little particles with quantum spin oriented in the same
• 24:43
  Speaker 2: way adding up, or like an electromagnet, like an electric
• 24:47
  Speaker 2: motor that comes because of current from electricity.
• 24:51
  Speaker 1: Interesting, and so I guess now the question is, since
• 24:53
  Speaker 1: black holes can have an electric charge and also spin,
• 24:58
  Speaker 1: can they also have a magnetic field. So let's dig
• 25:02
  Speaker 1: into that. But first let's take a quick break. All right,
• 25:17
  Speaker 1: we're asking the question can a black hole have a
• 25:20
  Speaker 1: magnetic field? And what would happen if you put it
• 25:23
  Speaker 1: on your fridge?
• 25:26
  Speaker 2: You would eat everything in your fridge.
• 25:29
  Speaker 1: There you go. You can blame that also on a
• 25:32
  Speaker 1: black hole.
• 25:33
  Speaker 2: I don't know who finished the pie, honey, really, I don't.
• 25:36
  Speaker 2: Maybe it was a black hole in the middle of
• 25:37
  Speaker 2: the night. Check the camera.
• 25:39
  Speaker 1: Yeah me, Rich, I'll put a black hole in the
• 25:41
  Speaker 1: fridge there.
• 25:43
  Speaker 2: The new black hole diet by Daniel Yeah.
• 25:46
  Speaker 1: I don't think that sounds it's work.
• 25:49
  Speaker 2: I might need to work shop that a bit.
• 25:51
  Speaker 1: Yeah, yeah, yeah, yeah, it's more like an excuse for
• 25:54
  Speaker 1: a bad diet. But yeah, so black holes do they have?
• 26:00
  Speaker 1: Getting feels like literally, if we have a tiny one,
• 26:02
  Speaker 1: would it stick to your fridge? That's kind of what
• 26:04
  Speaker 1: we're asking here today, right, right.
• 26:07
  Speaker 2: Yeah, it's a really cool question, and the answer is
• 26:11
  Speaker 2: it depends why am I not surprised? It depends on
• 26:17
  Speaker 2: your reference frame, It depends on your velocity. Because we
• 26:21
  Speaker 2: don't have magnetic monopoles. You can't just like throw a
• 26:24
  Speaker 2: monopole into a black hole and have it have a
• 26:27
  Speaker 2: magnetic field, like inherently. The only way for it to
• 26:31
  Speaker 2: have a magnetic field is for it to do what
• 26:33
  Speaker 2: electrons do and electric currents do, which is have a
• 26:36
  Speaker 2: charge and a spin. So take a black hole, spin
• 26:40
  Speaker 2: it and charge it by shooting like a beam of
• 26:42
  Speaker 2: electrons right near the event horizon, so it gets some
• 26:45
  Speaker 2: angular momentum and it gets some charge. In that case,
• 26:48
  Speaker 2: it will get a magnetic field because now it's spinning
• 26:51
  Speaker 2: relative to you. So if you have like a magnetometer
• 26:54
  Speaker 2: or something, you will measure a magnetic field near the event.
• 26:58
  Speaker 1: Horizon, sort of in the same way that like an
• 27:00
  Speaker 1: electron on its own can have an electric field because
• 27:04
  Speaker 1: it's a charge. It does charge and it has spin.
• 27:07
  Speaker 2: Yeah, exactly right.
• 27:08
  Speaker 1: Or like if you take a coil of wire and
• 27:11
  Speaker 1: you spin a bunch of electrons that is those that's
• 27:14
  Speaker 1: a charge spinning which creates a magnetic field.
• 27:16
  Speaker 2: Yeah, exactly. You make a coil of wire and you
• 27:19
  Speaker 2: run a current through it, that makes the magnetic field
• 27:21
  Speaker 2: through the coil, right. Or simply if you just have
• 27:24
  Speaker 2: a single line of wire, not a coil, and you
• 27:26
  Speaker 2: run electrons through it, then you're going to get a
• 27:29
  Speaker 2: magnetic field around the wire. But that magnetic field is
• 27:32
  Speaker 2: frame dependent. It depends on the electrons moving relative to
• 27:37
  Speaker 2: you through the wire. It only happens because electrons are moving.
• 27:41
  Speaker 2: It's charges in motion that give us magnetic fields. So
• 27:45
  Speaker 2: if you have your black hole and it's spinning near you,
• 27:48
  Speaker 2: you measure magnetic field. Now you get in your ship
• 27:51
  Speaker 2: and you start orbiting the black hole at exactly the
• 27:53
  Speaker 2: same rate it's spinning, so that when you look out
• 27:55
  Speaker 2: of your ship the black hole is not spinning relative
• 27:58
  Speaker 2: to you, then it no longer has a magnetic field.
• 28:01
  Speaker 2: The magnetic field is frame dependent.
• 28:04
  Speaker 1: Well, meaning that the magnetic field disappears or that you
• 28:08
  Speaker 1: don't feel it.
• 28:11
  Speaker 2: It's not there. I mean, we don't even know if
• 28:12
  Speaker 2: fields are real anyway, but you can't measure it, and
• 28:16
  Speaker 2: according to the physics, it isn't there. Like you do
• 28:19
  Speaker 2: the calculation, there's a prediction of no magnetic field there.
• 28:23
  Speaker 2: And the thing is the field itself. You like to think
• 28:25
  Speaker 2: of it as something physical. It's out there in the universe.
• 28:28
  Speaker 2: But the distinction between electric fields and magnetic fields, like
• 28:31
  Speaker 2: you were saying earlier, is a little bit arbitrary, and
• 28:33
  Speaker 2: it turns out to depend on your frame of reference.
• 28:36
  Speaker 2: And not just for black holes, also for the simple
• 28:39
  Speaker 2: situation of electron going down a wire. If you jump
• 28:42
  Speaker 2: in a car and you drive down the wire the
• 28:44
  Speaker 2: same speed as the electrons, the electrons only have an
• 28:47
  Speaker 2: electric field. But your buddy who's standing next to the wire,
• 28:50
  Speaker 2: he measures the electrons going through the wire, they have
• 28:52
  Speaker 2: a velocity. He will also see a magnetic field. So
• 28:55
  Speaker 2: magnetic fields are always frame dependent because they depend on velocity.
• 29:00
  Speaker 1: Well that's a little bit odd to me, I guess.
• 29:03
  Speaker 1: So let's say have like a loop of wire and
• 29:06
  Speaker 1: I run a current through it, and you're saying, if
• 29:08
  Speaker 1: I sit in the middle of it, on a like
• 29:11
  Speaker 1: an office chair and I spin myself that I'm not
• 29:13
  Speaker 1: going to feel the magnetic force.
• 29:15
  Speaker 2: Yeah. If you spin at the same rate that those
• 29:17
  Speaker 2: electrons are moving, so the electrons have no velocity relative
• 29:21
  Speaker 2: to you, then you will feel no magnetic field. You'll
• 29:24
  Speaker 2: sense no magnetic field. It's a timely a little bit
• 29:26
  Speaker 2: more complicated there because now we're spinning, so we have
• 29:29
  Speaker 2: acceleration and non inertial frames, so it's a little bit
• 29:32
  Speaker 2: simpler in the straight line case. But yeah, the same
• 29:35
  Speaker 2: thing applies, right.
• 29:36
  Speaker 1: I guess that's what I was trying to get at,
• 29:38
  Speaker 1: is that you're saying it it depends, but it doesn't
• 29:41
  Speaker 1: depend on like an inertial frame, which is sort of
• 29:44
  Speaker 1: like the standard frames of the universe. It's like you
• 29:46
  Speaker 1: have to make up this weird frame, right, like I
• 29:49
  Speaker 1: would be feeling other things. I won't feel that electromagnetic field,
• 29:53
  Speaker 1: but I'm going to feel, for example, uh, this interpretal force.
• 29:57
  Speaker 2: Yeah, exactly. And that's sort of the Missy piece because
• 30:00
  Speaker 2: you might be wondering, like, hold on a second. If
• 30:03
  Speaker 2: I'm measuring a magnetic field and my friend is not
• 30:06
  Speaker 2: measuring a magnetic field, how is that possible? If you
• 30:09
  Speaker 2: dropped a monopole into that situation, would it get pushed
• 30:11
  Speaker 2: or would it not get pushed? Right, there has to
• 30:14
  Speaker 2: be like one answer to that question, and the answer
• 30:17
  Speaker 2: is a little bit subtle but kind of beautiful. What
• 30:19
  Speaker 2: relativity tells us is that the same laws of physics
• 30:22
  Speaker 2: apply no matter what your reference frame, but the story
• 30:26
  Speaker 2: they tell about why things happen doesn't have to agree.
• 30:30
  Speaker 2: So in one scenario, your friend will say, oh, there's
• 30:32
  Speaker 2: a magnetic field there and it helps push things around.
• 30:35
  Speaker 2: The other person will say, no, there's no magnetic field there,
• 30:38
  Speaker 2: but they will also see the electric field is a
• 30:40
  Speaker 2: little bit different and that will compensate. So one person
• 30:43
  Speaker 2: will see a combination of electric and magnetic fields doing
• 30:47
  Speaker 2: pushes and pulls on charge particles and magnetic monopoles. Somebody
• 30:51
  Speaker 2: else will see only electric fields and no magnetic fields,
• 30:54
  Speaker 2: but they'll actually predict the same motion for all the particles.
• 30:58
  Speaker 2: They'll just have a different reason for why it happened.
• 31:01
  Speaker 1: Right. It's sort of like if you're moving with the electricity,
• 31:05
  Speaker 1: then you won't feel the forces of the electromagnetic field,
• 31:09
  Speaker 1: but you'll have to push and spin yourself around the wire,
• 31:13
  Speaker 1: which is sort of equivalent, I think, is what you're saying.
• 31:16
  Speaker 2: Yeah, all the differences actually add up to give the
• 31:19
  Speaker 2: same prediction, which is kind of amazing. And that's one
• 31:21
  Speaker 2: of the beautiful things about relativity is that it shows
• 31:24
  Speaker 2: you that all these pieces work together, because really the
• 31:28
  Speaker 2: distinction between electricity and magnetism is a bit arbitrary, and
• 31:32
  Speaker 2: it's even frame dependent. You know, people going at different
• 31:35
  Speaker 2: speeds see electric fields or magnetic fields. But all the
• 31:38
  Speaker 2: pieces work together, so that even people in different reference frames,
• 31:42
  Speaker 2: while they tell a different story about why things happen,
• 31:44
  Speaker 2: like did you have a magnetic field or not, they
• 31:46
  Speaker 2: will agree in these scenarios about what actually did happen.
• 31:50
  Speaker 1: But I wonder if you can just can you just
• 31:52
  Speaker 1: say the same thing about everything in the universe. You know,
• 31:55
  Speaker 1: like you could also make gravity disappear if you move
• 31:59
  Speaker 1: with the grat, or you can make like a charge
• 32:02
  Speaker 1: disappear if you move with the charges.
• 32:04
  Speaker 2: Not everything in the universe is frame dependent. For example,
• 32:07
  Speaker 2: black holes are not. If there's a black hole, then
• 32:10
  Speaker 2: everybody agrees there's a black hole. You can't like boost
• 32:13
  Speaker 2: yourself into some frame in which there is no black hole.
• 32:17
  Speaker 2: This is why, for example, you can't make a black
• 32:19
  Speaker 2: hole just by going really really fast. You might think, oh,
• 32:22
  Speaker 2: black holes are actually happen when you have a lot
• 32:24
  Speaker 2: of energy, not just mass. So why can't I make
• 32:27
  Speaker 2: a black hole by taking a particle and zooming it
• 32:29
  Speaker 2: to really high speeds because that would make a frame
• 32:32
  Speaker 2: dependent black hole, which doesn't exist in our universe. So
• 32:35
  Speaker 2: there are some things that are invariant no matter what
• 32:38
  Speaker 2: frame you're in, inertial or not. But yeah, there are
• 32:41
  Speaker 2: a lot of things in the universe that are frame dependent,
• 32:43
  Speaker 2: I think more than people suspect, right.
• 32:46
  Speaker 1: I wonder if the analogy is sort of like, you know,
• 32:48
  Speaker 1: if you jump out of an airplane and you're falling
• 32:50
  Speaker 1: towards Earth, you can't tell that there's a planet there
• 32:53
  Speaker 1: blow you right, Like, to you, it's going to feel
• 32:55
  Speaker 1: like you're floating in space as you plummet to your death.
• 32:58
  Speaker 2: Yeah, that's right in that scenario. Actually, in freefall, you're
• 33:02
  Speaker 2: not doing any accelerating. It's the planet that's accelerating towards you.
• 33:05
  Speaker 2: The surface of the planet is accelerating towards you. If
• 33:08
  Speaker 2: you take out a gravitometer or an accelerometer in that scenario,
• 33:12
  Speaker 2: you'll measure no acceleration, So you need to look out
• 33:15
  Speaker 2: the window to see a planet rushing towards you to
• 33:18
  Speaker 2: discover that your life span is going to be very short.
• 33:21
  Speaker 1: Right, So in that way, sort of gravity is also
• 33:23
  Speaker 1: reference dependent, Right, I can make it disappear if I
• 33:26
  Speaker 1: jump out of an airplane.
• 33:27
  Speaker 2: Lots of gravitational effects are frame dependent. Yes, there are
• 33:30
  Speaker 2: some things that are frame independent, like the existence of
• 33:33
  Speaker 2: a black hole, but a lot of things are frame dependent, absolutely,
• 33:36
  Speaker 2: And you're right that this story applies very broadly. There's
• 33:39
  Speaker 2: lots of situations in physics where people will disagree about
• 33:43
  Speaker 2: why things happened, even if they apply the same rules,
• 33:46
  Speaker 2: and they might agree about what happened, they'll tell a
• 33:49
  Speaker 2: different story about how that happened or why that happened,
• 33:52
  Speaker 2: even though the outcome is the same.
• 33:55
  Speaker 1: But I guess if you stick to what most people
• 33:58
  Speaker 1: think is normal, which is like an inertial frame or
• 34:02
  Speaker 1: you know, not spin around at a crazy speed in
• 34:05
  Speaker 1: an office chair, then you would say that a black
• 34:08
  Speaker 1: hole does have a magnetic field.
• 34:10
  Speaker 2: Yeah, exactly, and it's not special, right. The black hole
• 34:12
  Speaker 2: has a magnetic field, and exactly the same way a
• 34:15
  Speaker 2: coil of wire has a magnetic field. You got charge
• 34:18
  Speaker 2: in there, You've got spin, so you're moving charges, so
• 34:21
  Speaker 2: you get a magnetic field. The magnetic field of a
• 34:23
  Speaker 2: black hole is not deficient in any way compared to
• 34:27
  Speaker 2: the magnetic field from an electromagnetic motor, for example.
• 34:31
  Speaker 1: And I guess what that means is that if I
• 34:32
  Speaker 1: take a compass and I hold it up close to
• 34:35
  Speaker 1: a black hole, I'm going to see it point in
• 34:37
  Speaker 1: a specific direction, right, just like it points to a
• 34:40
  Speaker 1: specific direction here on Earth.
• 34:42
  Speaker 2: Yeah, exactly, a black hole have a magnetic field the
• 34:45
  Speaker 2: way the Earth does. And we think the Earth's magnetic
• 34:47
  Speaker 2: field probably comes from convection and flow of stuff inside
• 34:51
  Speaker 2: the Earth, though we don't totally understand. And so yeah,
• 34:54
  Speaker 2: you could use a compass to navigate near a magnetic
• 34:57
  Speaker 2: black hole.
• 34:59
  Speaker 1: So I mean black holes have a north and south pole.
• 35:01
  Speaker 2: Yeah, exactly, they have a north and south pole for
• 35:03
  Speaker 2: their spin as well. Right, A black hole that doesn't
• 35:05
  Speaker 2: spin is spherically symmetric, But a spinning black hole has
• 35:09
  Speaker 2: broken that symmetry because there has to be some axis
• 35:12
  Speaker 2: around which it's spinning. So that gives it a north
• 35:14
  Speaker 2: and south spin black hole, because that spin is what
• 35:17
  Speaker 2: generates the magnetic field. It also then has a north
• 35:20
  Speaker 2: and south magnetic pole.
• 35:22
  Speaker 1: Whoa, And so if I have a tiny spinning black hole,
• 35:25
  Speaker 1: then it would be attracted to my fridge door.
• 35:28
  Speaker 2: Right, Yes, it would be attracted to your fridge door.
• 35:31
  Speaker 2: Even if its gravity was too weak to hold it there,
• 35:34
  Speaker 2: its magnetic field might be powerful enough, because remember, magnetic
• 35:38
  Speaker 2: fields are much more powerful than gravity. So you make
• 35:41
  Speaker 2: a tiny black hole out of a few electrons, it
• 35:44
  Speaker 2: might not have very strong gravity, but the magnetic fields
• 35:46
  Speaker 2: could already be quite powerful.
• 35:48
  Speaker 1: Yeah, it's interesting to think that a black hole has
• 35:50
  Speaker 1: a north and south pole. I hear the north pole
• 35:53
  Speaker 1: of a black hole is where all the dark elves
• 35:55
  Speaker 1: hang out.
• 35:59
  Speaker 2: Are they making presence for dark Christmas?
• 36:02
  Speaker 1: And now they're just making a bunch of coal presents
• 36:06
  Speaker 1: for everyone? It's the opposite. It's the opposite. Can you
• 36:10
  Speaker 1: measure the magnetic field of a black hole from a distance?
• 36:13
  Speaker 2: In principle, if you were near the black hole, you
• 36:15
  Speaker 2: can do what we describe, which is used the compass.
• 36:17
  Speaker 2: We can't go near black holes, unfortunately, but we can
• 36:21
  Speaker 2: see the effect of black holes on nearby particles. Right,
• 36:25
  Speaker 2: black holes are almost never on their own. They formed
• 36:27
  Speaker 2: because they're in the middle of some dense blob of
• 36:29
  Speaker 2: matter they've been gobbling, so usually there's a lot of
• 36:33
  Speaker 2: stuff around them. And if you trace the path of
• 36:35
  Speaker 2: the charged particles near the black hole, then you can
• 36:38
  Speaker 2: measure something about its magnetic field. But those particles also
• 36:43
  Speaker 2: will generate a magnetic field. So teasing those two things
• 36:46
  Speaker 2: apart is quite tricky.
• 36:47
  Speaker 5: Mmm.
• 36:48
  Speaker 1: Sort of like give you throw a bunch of iron
• 36:51
  Speaker 1: filings feelings filings at a black hole, they would form
• 36:54
  Speaker 1: a pattern around the black hole, and that would tell you, Oh,
• 36:56
  Speaker 1: that's the magnetic field, that's where the north pole is pointing.
• 37:00
  Speaker 2: Yeah, it's filings. If it's little pieces of shaved iron,
• 37:03
  Speaker 2: it's fillings. If they came from people's teeth, which were.
• 37:05
  Speaker 1: You imagine both? I guess, I guess both would work.
• 37:12
  Speaker 2: I guess if you go near a black hole, it
• 37:13
  Speaker 2: might pull out your iron fillings. What if you file
• 37:16
  Speaker 2: some fillings, I'm going to find a complaint with the
• 37:18
  Speaker 2: black hole division if.
• 37:19
  Speaker 1: That happens, another full.
• 37:21
  Speaker 2: I think they're filled up already.
• 37:24
  Speaker 1: Yeah, all right, So then could we measure it potentially
• 37:27
  Speaker 1: from Earth? Like if we you know, we have these
• 37:29
  Speaker 1: pictures now of what we think are black holes. Could
• 37:31
  Speaker 1: we measure their magnetic feel from here?
• 37:34
  Speaker 2: Absolutely, we can and we have we have.
• 37:38
  Speaker 1: All right, well let's talk about that, but work, let's
• 37:40
  Speaker 1: take another quick break. All right, we're talking about the
• 37:56
  Speaker 1: polarity of a black hole. They're very polarizing black holes.
• 38:01
  Speaker 1: Some people love them, some people really love them.
• 38:04
  Speaker 2: Those are your only two choices.
• 38:06
  Speaker 1: Yeah, you either either love it or you don't love it.
• 38:10
  Speaker 2: Fill out this survey or what take your iron fillings?
• 38:12
  Speaker 1: Well, we talked about how black hole has a magnetic field,
• 38:15
  Speaker 1: but it's sort of not new information, right, Like it's
• 38:19
  Speaker 1: it's it's the product of its charge and it's been
• 38:22
  Speaker 1: so it's not like it has a fourth property that
• 38:25
  Speaker 1: you can find out about it. It's it's sort of
• 38:27
  Speaker 1: a derivative of its charge and spin.
• 38:30
  Speaker 2: Yeah, exactly, not derivative in the calculus sense, but derivative
• 38:34
  Speaker 2: in the like, oh you just copied that sense. It
• 38:36
  Speaker 2: comes out of the other properties. It's not a core
• 38:39
  Speaker 2: basic quantity of a black hole itself, unless the black
• 38:41
  Speaker 2: hole had a magnetic monopole in it, and then it
• 38:44
  Speaker 2: would be a core property. But you're right, it sort
• 38:46
  Speaker 2: of emerges from the other properties.
• 38:49
  Speaker 1: What do you mean if a black hole ada monopole.
• 38:51
  Speaker 2: If a black hole aida monopole would be something we
• 38:54
  Speaker 2: call a dionic black hole, and it would have its
• 38:56
  Speaker 2: own monopole magnetic field, just like the monopole that fell
• 39:00
  Speaker 2: into it, Right.
• 39:02
  Speaker 1: How would it ever eat a monopole number one?
• 39:04
  Speaker 2: A monopole would have to exist in the universe, and
• 39:06
  Speaker 2: we don't know that they do, but they might, and
• 39:08
  Speaker 2: then they would have to go near a black hole.
• 39:10
  Speaker 2: And then gobble gobble.
• 39:12
  Speaker 1: Could a black hole split a dipole into a two
• 39:15
  Speaker 1: monopoles that it eats one and it shoots off the
• 39:17
  Speaker 1: other one.
• 39:17
  Speaker 2: That would be an awesome feature of quantum gravity. Currently
• 39:20
  Speaker 2: in our predictions, know, you can't split a diepole because like,
• 39:24
  Speaker 2: where does that come from? It comes from the electron spinning,
• 39:26
  Speaker 2: So you're going to split the electron somehow, So we
• 39:29
  Speaker 2: don't know how to do that.
• 39:31
  Speaker 1: I don't know in general, can you tell a black
• 39:32
  Speaker 1: hole what it can or can't do?
• 39:35
  Speaker 2: If black holes are listening to this podcast, I apologize
• 39:38
  Speaker 2: for my presumptuousness.
• 39:40
  Speaker 1: They're going to come after your fridge watch out, all right, Well,
• 39:46
  Speaker 1: so what can we see of a black hole or
• 39:49
  Speaker 1: what have we seen?
• 39:50
  Speaker 2: So we've seen. The black holes have a huge effect
• 39:52
  Speaker 2: on nearby matter. They don't just suck stuff in, they
• 39:55
  Speaker 2: also shunt stuff away from themselves. Their magnetic feels can
• 39:59
  Speaker 2: be so strong that in falling particles can actually follow
• 40:02
  Speaker 2: those magnetic fields and then escape the black hole, you know,
• 40:06
  Speaker 2: the same way that like we've seen these aurora. Because
• 40:08
  Speaker 2: charge particles falling in towards the Earth end up spiraling
• 40:11
  Speaker 2: around our magnetic fields and then end up in the
• 40:14
  Speaker 2: North Pole. It's also possible when particles are falling in
• 40:17
  Speaker 2: towards a black hole. Basically the same thing happens, but
• 40:20
  Speaker 2: they get so much speed that they then escape the
• 40:22
  Speaker 2: grip of the black hole and they shoot out up
• 40:25
  Speaker 2: and down the North and South poles. And we see
• 40:28
  Speaker 2: these enormous jets from black holes. You see galaxies with
• 40:32
  Speaker 2: super massive black holes at their center, and then these
• 40:35
  Speaker 2: huge jets extending thousands of light years up and down,
• 40:38
  Speaker 2: sort of above and below the plane of the galaxy.
• 40:41
  Speaker 2: Those are jets from the central black hole, and they're
• 40:44
  Speaker 2: powered by its magnetic field.
• 40:46
  Speaker 1: Whoa wait, wait, wait, wait, hold on, it's not stuff
• 40:49
  Speaker 1: coming out of the black hole, is it right? It's
• 40:51
  Speaker 1: not right, because nothing can escape a black hole.
• 40:53
  Speaker 2: It's not something escaping a black hole. It's something having
• 40:56
  Speaker 2: a near miss. It's like fell in and then a
• 40:59
  Speaker 2: magnetic field outside the black hole, the same way we
• 41:02
  Speaker 2: have a magnetic field outside the atmosphere of the Earth.
• 41:05
  Speaker 2: The magnetic field that's outside the black hole guides those
• 41:08
  Speaker 2: particles towards the north and then they escape, but they
• 41:11
  Speaker 2: never went inside the event horizon.
• 41:14
  Speaker 1: I see now, I wonder if that means that a
• 41:17
  Speaker 1: black hole looks different to like an electron than it
• 41:20
  Speaker 1: does to a proton.
• 41:22
  Speaker 2: Potentially, they definitely do look a little bit different. I mean,
• 41:26
  Speaker 2: a proton and an electron have different charges, and so
• 41:29
  Speaker 2: they're affected differently by those magnetic fields. But all these
• 41:33
  Speaker 2: particles do see the same event horizon. The event horizon
• 41:36
  Speaker 2: is the event horizon is the event horizon.
• 41:39
  Speaker 1: But wouldn't they like their paths near a black hole
• 41:41
  Speaker 1: be different, in which case the point at which they
• 41:44
  Speaker 1: would definitely fall in is different.
• 41:46
  Speaker 2: Yeah, the paths near the event horizon are different because
• 41:49
  Speaker 2: they are affected by magnetic fields differently, and their masses
• 41:52
  Speaker 2: are different, et cetera, and their charges are different. But
• 41:55
  Speaker 2: the event horizon is still just the event horizon. That's
• 41:58
  Speaker 2: a feature of the curvature of space. It's not an
• 42:00
  Speaker 2: issue of like the forces on the particles. Remember, it's
• 42:03
  Speaker 2: a product of the black hole itself.
• 42:08
  Speaker 1: And that's just from the mcdaide field of the black
• 42:10
  Speaker 1: hole itself. You mentioned earlier that the stuff swirling around
• 42:13
  Speaker 1: it can also make mcnad fields.
• 42:15
  Speaker 2: Yeah, exactly. There's huge accretion disks surrounding most black holes,
• 42:19
  Speaker 2: especially the ones at the center of galaxies that have
• 42:21
  Speaker 2: been feeding on gas and dust, and so there's a
• 42:24
  Speaker 2: lot of stuff that has fallen close to the black
• 42:27
  Speaker 2: hole and is still in orbit around it. Remember, things,
• 42:30
  Speaker 2: unless they fall directly towards the center of the black
• 42:32
  Speaker 2: hole or towards the event horizon, they're still going to
• 42:35
  Speaker 2: have some angular momentum. You can orbit a black hole
• 42:37
  Speaker 2: the same way the Moon orbits the Earth. Black Holes
• 42:40
  Speaker 2: are not like literally sucking things in. They're just gravity, right,
• 42:43
  Speaker 2: They're just curvature of space. You could in principle, orbit
• 42:46
  Speaker 2: a black hole forever and never fall in. But if
• 42:49
  Speaker 2: you're in this big disc of gas and dust, you're
• 42:52
  Speaker 2: also going to have friction. You're going to bump up
• 42:53
  Speaker 2: against each other, and some stuff is going to end
• 42:55
  Speaker 2: up falling in. But before it does. You know, this
• 42:58
  Speaker 2: huge disc of gas and tidal forces are heating it up,
• 43:01
  Speaker 2: so it's really hot and energetic and glowing in the
• 43:04
  Speaker 2: X ray. And because it's a lot of charged particles
• 43:07
  Speaker 2: swirling around, it has its own very strong magnetic field.
• 43:12
  Speaker 1: Like it adds to the black holes. Is a magnetic
• 43:15
  Speaker 1: field or it cancels it? Or how does it interact
• 43:18
  Speaker 1: with the black holes? Is magnetic field itself?
• 43:21
  Speaker 2: Yeah, great question, and that's essentially the cutting edge of
• 43:23
  Speaker 2: our research right now. It's like, what do the black
• 43:26
  Speaker 2: hole magnetic fields look like? What are the magnetic fields
• 43:29
  Speaker 2: coming from the disc look like? It depends a lot
• 43:31
  Speaker 2: on how calm or how turbulent that accretion disc is. Like,
• 43:35
  Speaker 2: if everything is flowing very nicely, like Saturn's rings, then
• 43:40
  Speaker 2: all those magnetic fields will add up very nicely and
• 43:42
  Speaker 2: they'll all contribute in the same direction. But if it's
• 43:45
  Speaker 2: sort of chaotic, like a big storm, then the magnetic
• 43:48
  Speaker 2: fields generated by those particles might cancel each other out.
• 43:51
  Speaker 2: We also don't really know how much of the magnetic
• 43:53
  Speaker 2: field is coming from the disc and how much is
• 43:55
  Speaker 2: coming from the black hole itself. We can't separate those
• 43:58
  Speaker 2: two things very easily.
• 44:00
  Speaker 1: We can't because it's just too complicated.
• 44:02
  Speaker 2: Yeah, we don't really understand how much magnetic field there
• 44:05
  Speaker 2: is coming from the accretion disc because it's not something
• 44:07
  Speaker 2: we've modeled very well. We have lots of competing theories
• 44:10
  Speaker 2: about what the accretion disc looks like, and so to
• 44:13
  Speaker 2: separate out the black holes magnetic field you have to
• 44:16
  Speaker 2: understand the rest of the magnetic field very well. But
• 44:18
  Speaker 2: we've tried to do that. We've been able to take
• 44:21
  Speaker 2: these images of the event horizon or images of the
• 44:24
  Speaker 2: stuff near the event horizon, and recent pictures of that
• 44:28
  Speaker 2: have used some clever tricks to try to understand what
• 44:30
  Speaker 2: the magnetic fields look like near the black hole.
• 44:33
  Speaker 1: WHOA, how can you do that? Well, first of all,
• 44:35
  Speaker 1: you can't really see the event horizon, right, You only
• 44:37
  Speaker 1: see the shadow of the black hole, which is different.
• 44:40
  Speaker 2: Yeah, that's exactly right. We're just not seeing photons from
• 44:43
  Speaker 2: the event horizon or anywhere near it in a way
• 44:45
  Speaker 2: that lines up really really well with predictions of general relativity.
• 44:49
  Speaker 2: And so that's an indirect piece of evidence for black holes.
• 44:52
  Speaker 2: Another frustrating the indirect piece of evidence. But we can
• 44:55
  Speaker 2: see the stuff the accretion disc nearby it. That's why
• 44:58
  Speaker 2: these photos look sort of like a big crispy cream donut.
• 45:01
  Speaker 3: Right.
• 45:01
  Speaker 2: You have the hot gas glowing near the accretion disk,
• 45:04
  Speaker 2: and those photons that come from the gas that are
• 45:07
  Speaker 2: emitted from these high speed charged particles. They can give
• 45:10
  Speaker 2: us some clues about the magnetic field that they're in
• 45:13
  Speaker 2: because the magnetic fields will polarize these photons. It changes
• 45:17
  Speaker 2: how the photons wiggle, like are they wiggling this way
• 45:19
  Speaker 2: or they're wiggling that way. And if the magnetic fields
• 45:22
  Speaker 2: are all nicely organized, then the polarization of those photons
• 45:25
  Speaker 2: will be nicely organized. And if the magnetic fields are
• 45:28
  Speaker 2: all a big hot mess, then the polarizations will all
• 45:30
  Speaker 2: be scrambled. So they recently reanalyze the image of the
• 45:34
  Speaker 2: black hole at the heart of the eighty seven galaxy
• 45:37
  Speaker 2: to try to measure the polarization of these photons, not
• 45:40
  Speaker 2: just like where's it bright and where's it dim, but
• 45:42
  Speaker 2: in which direction of those photons wiggling, and that give
• 45:46
  Speaker 2: them some clues about what might be happening in the
• 45:48
  Speaker 2: accretion disc.
• 45:49
  Speaker 1: WHOA, which would then sort of tell you what's going on, right.
• 45:52
  Speaker 2: Yeah, exactly, And it's really fun. They had two models
• 45:55
  Speaker 2: of black hole accretion disc magnetic fields. One of them
• 45:58
  Speaker 2: was called sane stable and normal evolution as ANE, and
• 46:04
  Speaker 2: the other one is called mad magnetically arrested disc. So
• 46:08
  Speaker 2: it was a big competition between the scene and the
• 46:11
  Speaker 2: MAD groups.
• 46:14
  Speaker 1: They're like, no, I'm saying, no, you're mad.
• 46:17
  Speaker 2: I mean, you've heard of crazy astronomical acronyms before, but
• 46:21
  Speaker 2: this is like dueling crazy acronyms. I'm impressed by their coordination.
• 46:25
  Speaker 1: Yeah, so each one of these was invented by a
• 46:27
  Speaker 1: different group.
• 46:28
  Speaker 2: Yeah, exactly. They like competing theories for how the accretion
• 46:31
  Speaker 2: disc will come together. And basically the difference between them
• 46:35
  Speaker 2: is how turbulent is it and how coherent is it?
• 46:38
  Speaker 2: You know, is it basically all scrambled and you don't
• 46:40
  Speaker 2: get a strong magnetic field, or is it kind of
• 46:42
  Speaker 2: coherent and well ordered, in which case you do get
• 46:45
  Speaker 2: a stronger build up of the magnetic fields from the
• 46:47
  Speaker 2: accretion disc, right right?
• 46:49
  Speaker 1: Or are they all just crazy physicists.
• 46:52
  Speaker 2: Yeah, And so for a long time people thought that
• 46:54
  Speaker 2: the same scenario was more natural sort of weaker fields
• 46:58
  Speaker 2: because everything would be sort of more scrambled. But what
• 47:01
  Speaker 2: they measured is more consistent with the mad scenario that
• 47:05
  Speaker 2: things are like nicely organized, so they all add up
• 47:08
  Speaker 2: to give more powerful magnetic fields than people.
• 47:10
  Speaker 1: Suspected, meaning that the black hole is not as chaotic
• 47:14
  Speaker 1: as we thought it was.
• 47:15
  Speaker 2: Yeah, it turns out to be a little bit tidy.
• 47:17
  Speaker 1: Wait, the mad scenario is more sane than the same scenario.
• 47:23
  Speaker 2: The mad scenario is more like our universe. It's the
• 47:26
  Speaker 2: one where things are better organized.
• 47:28
  Speaker 1: Yeah, it sounds like physicists are just trying to drive
• 47:32
  Speaker 1: as mad. All right, Well, I think that sort of
• 47:36
  Speaker 1: answers the question. Black holes do have magnetic fields. I
• 47:39
  Speaker 1: mean they have Spain in charge, which means they'd have
• 47:42
  Speaker 1: magnetic fields. You can take a black holes, stick it
• 47:44
  Speaker 1: on your fridge. You can use it to mess up
• 47:47
  Speaker 1: your friend's compass. But measuring it might be a little
• 47:50
  Speaker 1: bit tricky because it's so far away, and there's also
• 47:53
  Speaker 1: these weird physics and dynamics going on or around outside
• 47:58
  Speaker 1: of it.
• 47:58
  Speaker 2: That's right. We can't know what's going on inside a
• 48:00
  Speaker 2: black hole, but magnetic fields give us a pretty good
• 48:03
  Speaker 2: clue as to what's going on near a black hole,
• 48:05
  Speaker 2: which one day might help us gain some clues about
• 48:08
  Speaker 2: what's going on past the event horizon.
• 48:11
  Speaker 1: Whoa do you think we can use magnets to see
• 48:14
  Speaker 1: what's inside of a black hole? It's kind of what
• 48:16
  Speaker 1: you're saying.
• 48:16
  Speaker 2: Well, in general relativity we definitely cannot, But in a
• 48:19
  Speaker 2: quantum version, with quantum gravity, there could be some correlation
• 48:23
  Speaker 2: between the information on the surface of the event horizon
• 48:26
  Speaker 2: itself and what's going on inside. There could be some feature,
• 48:29
  Speaker 2: some hair to the black hole, and that could affect,
• 48:32
  Speaker 2: for example, the radiation and the magnetic fields. And so eventually,
• 48:36
  Speaker 2: if we get detailed enough information and better theories of
• 48:39
  Speaker 2: quantum gravity, we might be able to see what's inside them.
• 48:42
  Speaker 1: That would be insane.
• 48:43
  Speaker 2: I wouldn't be mad about it.
• 48:46
  Speaker 1: Well, you know what they say, wearing magnets can really
• 48:48
  Speaker 1: help you out.
• 48:49
  Speaker 2: Do they say that that sounds like pseudoscience?
• 48:55
  Speaker 1: Well, honestly, all this black holes so also sounds a
• 48:58
  Speaker 1: little bit like sseuiccience.
• 49:00
  Speaker 2: Definitely not the final word on how any of this
• 49:02
  Speaker 2: stuff works. Is just science in progress.
• 49:05
  Speaker 1: I see, it's not pseudoscience. It's pre science science, and
• 49:11
  Speaker 1: it's key. Everything is pre science. Nothing is the proto science.
• 49:15
  Speaker 1: That sounds better proto.
• 49:16
  Speaker 2: Science science in action.
• 49:18
  Speaker 1: About that, that's right, you don't want to be a
• 49:20
  Speaker 1: pre scientist. All right? Well, another reminder about the incredible
• 49:24
  Speaker 1: mysteries out there in the universe and how they're staring
• 49:27
  Speaker 1: us right in our telescopes. You can see them, you
• 49:29
  Speaker 1: can point telescopes, you can measure things about them, but
• 49:33
  Speaker 1: all you see is pure.
• 49:36
  Speaker 2: Unknown and their magnetic personalities.
• 49:39
  Speaker 1: That's right, the riz. Well, we hope you enjoyed that.
• 49:42
  Speaker 1: Thanks for joining us. See you next time.
• 49:49
  Speaker 2: For more science and curiosity, come find us on social
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  Speaker 2: media where we answer questions and post videos. We're on Twitter,
• 49:56
  Speaker 2: disc Org, Instant, and now TikTok. Thanks for listening, and
• 50:00
  Speaker 2: remember that Daniel and Jorge Explain the Universe is a
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  Speaker 2: favorite shows.