Latest / Daniel and Kelly’s Extraordinary Universe / Why black holes are actually bright.

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Why black holes are actually bright. · Daniel and Kelly’s Extraordinary Universe

• 0:08
  Speaker 1: Hey, Jorgey, I have a pop quiz for you. Was
• 0:12
  Speaker 1: this in the syllabus? Did you read the syllabus? And
• 0:16
  Speaker 1: then another was one? Then yes, it was on the syllabus.
• 0:19
  Speaker 1: All right, that sounds fair. All right, hit me up.
• 0:22
  Speaker 1: What is the object that astronomers call a blondet? Interesting?
• 0:28
  Speaker 1: It sounds like a block internet, maybe like the less
• 0:31
  Speaker 1: exciting version of the Internet. Close. All right, well it's
• 0:36
  Speaker 1: it's it's astronomy. So I'm guessing maybe it sounds like planet,
• 0:40
  Speaker 1: but maybe it's like a black planet or or i know,
• 0:44
  Speaker 1: like a black hole planet ding ding ding. You it's
• 0:47
  Speaker 1: a planet that orbits a black hole. Oh? Interesting? So
• 0:51
  Speaker 1: sometimes astronomy does come up with sort of names that
• 0:55
  Speaker 1: makes sense. Sometimes it's being generous. Just be glad I
• 0:58
  Speaker 1: didn't ask you what a plun it is. I'm glad
• 1:01
  Speaker 1: you didn't ask me that what what a plunent is? Weight?
• 1:04
  Speaker 1: Is a pluted a real thing? Absolutely? Is it a
• 1:07
  Speaker 1: more pluish version of the Internet. Hi am or Handmae
• 1:25
  Speaker 1: cartoonists and the creator of PhD commics. Hi, I'm Daniel.
• 1:28
  Speaker 1: I am a particle physicist and a professor UC Irvine,
• 1:31
  Speaker 1: and I would never joke about plunets. Does that make
• 1:34
  Speaker 1: you a plute? Pessor I always try to tell the plute, well,
• 1:40
  Speaker 1: that's a real plus. But plunets are a real thing. Really,
• 1:44
  Speaker 1: what are they? What's a plutt? A plunt is a
• 1:47
  Speaker 1: moon turned planet. It used to be a moon orbiting
• 1:50
  Speaker 1: a planet, but then it was set free and is
• 1:53
  Speaker 1: now wandering the Solar System and counts as a planet. Oh. Interesting,
• 1:58
  Speaker 1: so you started the word moon inside of the planet.
• 2:01
  Speaker 1: Interesting You didn't like combine it or you like literally
• 2:05
  Speaker 1: merged it. Yeah, exactly. You know, take the old job
• 2:08
  Speaker 1: and in certain inside the new jobs. So for example,
• 2:11
  Speaker 1: you know your job would be car engineer, tunist engineers.
• 2:17
  Speaker 1: I like that a little bit better engineer engineers. There
• 2:21
  Speaker 1: you go, anything that involves ingenuity, and you're no longer
• 2:25
  Speaker 1: orbiting anything but Welcome to our podcast Daniel and Jorge
• 2:28
  Speaker 1: Explain the Universe, a production of I Heart Radio in
• 2:31
  Speaker 1: which we mash up all of the crazy ideas that
• 2:34
  Speaker 1: are out there in the universe. The planets, the moons,
• 2:36
  Speaker 1: the pluets, the blondet's, the black holes, the new drown stars,
• 2:40
  Speaker 1: the quasars, the tiny little particles, and even the hypothetical
• 2:43
  Speaker 1: stuff that might not exist all in a desperate attempt
• 2:47
  Speaker 1: to understand this glorious and incredible universe that we find
• 2:51
  Speaker 1: ourselves in that provides us with so many satisfying, deep, rich,
• 2:55
  Speaker 1: and cosmically contextual questions about the nature and meaning of
• 2:59
  Speaker 1: our lives. Cosmically contextual questions. That's a great alliteration there,
• 3:04
  Speaker 1: it's positivitivitally fluish. I am inspiring a literationist, but it
• 3:09
  Speaker 1: is at an incredible and wonderful universe out there, full
• 3:12
  Speaker 1: of interesting things that we've named, that we haven't named,
• 3:15
  Speaker 1: things that we understand, and things that we don't understand
• 3:18
  Speaker 1: and we have yet to understand and that will hopefully
• 3:20
  Speaker 1: learn more about in the future. That's right, it's a
• 3:23
  Speaker 1: never ending journey to answer the questions about the universe.
• 3:27
  Speaker 1: Or he asked me earlier, if somebody is wants a physicist,
• 3:30
  Speaker 1: if they're always a physicist, and I think that the
• 3:32
  Speaker 1: answer is that everybody out there is a physicist because
• 3:35
  Speaker 1: we all want to know answers to the deepest questions
• 3:39
  Speaker 1: about the universe. Yeah, we all have questions, we all
• 3:41
  Speaker 1: wonder about the world around us. And I guess that
• 3:44
  Speaker 1: makes you a physicist, right, I mean technically, anyone who
• 3:47
  Speaker 1: wonders about the universe and how it works is sort
• 3:49
  Speaker 1: of a scientist, right. Yeah, physics is just trying to
• 3:52
  Speaker 1: tell mathematical stories to answer our questions about the universe,
• 3:56
  Speaker 1: and we all have those questions and trying to build
• 3:58
  Speaker 1: in our heads models about how the universe works. Professional
• 4:02
  Speaker 1: physicists who do it for their day job take it
• 4:04
  Speaker 1: one step further and devote their lives to it. But
• 4:07
  Speaker 1: I think it's something that everybody and some level is doing. Interesting.
• 4:10
  Speaker 1: Does that mean you go around saying, Hi, I'm a
• 4:12
  Speaker 1: pro physicist. Stand back, I'm a professional. That's right. Like
• 4:19
  Speaker 1: professional wrestlers. You need to take professional physicists much more seriously. Yeah,
• 4:23
  Speaker 1: I'm sure you get paid as much as professional athletes
• 4:25
  Speaker 1: as well. You should see me in costume. Yeah, and
• 4:28
  Speaker 1: I'm sure there's an n p A also a National
• 4:31
  Speaker 1: Physics Association, Right. You have a world championship too, Oh yeah,
• 4:35
  Speaker 1: we call it a SmackDown. Also, you technically kind of
• 4:38
  Speaker 1: have teams, right like you and the people in your department.
• 4:41
  Speaker 1: You're sort of a team, and you're sort of competing
• 4:42
  Speaker 1: against other teams in a way, right to uncover the
• 4:45
  Speaker 1: secrets of the universe. That's true. We do have a
• 4:47
  Speaker 1: group here at Irvine that all sort of works together
• 4:50
  Speaker 1: probing the universe in different ways, plasma physics, condensed matter physics,
• 4:54
  Speaker 1: all the way to astronomy um also a member of
• 4:57
  Speaker 1: other teams like I'm a member of the Atlas Collaboration,
• 5:00
  Speaker 1: which is a group of thousands of scientists all working
• 5:02
  Speaker 1: together to try to understand the basic constituents of matter.
• 5:06
  Speaker 1: And we have competition. The CMS Collaboration is like five
• 5:09
  Speaker 1: thousand other scientists trying to beat us to the punch. Interesting.
• 5:13
  Speaker 1: How many teams are you a part of that? Do? It?
• 5:15
  Speaker 1: Sounds like you're very promising businesses. I'm a prolific collaborator,
• 5:18
  Speaker 1: that's true. Yes, you're a professional, prolific promisk business That
• 5:22
  Speaker 1: sounds very positive. Well, I'm pro you anyways. But yeah,
• 5:26
  Speaker 1: it's an interesting universe full of mysterious things, and nothing
• 5:29
  Speaker 1: is more mysterious, it seems, than an interesting object that
• 5:33
  Speaker 1: we thought was theoretical for a long time, but that
• 5:36
  Speaker 1: we now have pictures of out there in the cosmos.
• 5:39
  Speaker 1: Maybe the most challenging thing to wrap our minds around
• 5:42
  Speaker 1: to understand that it might really be out there in
• 5:45
  Speaker 1: our universe. Not just a product of mathematical calculations, but
• 5:49
  Speaker 1: a reality, something one could actually fall into and experience,
• 5:53
  Speaker 1: something one could actually see with their own eyes. Are
• 5:56
  Speaker 1: these weird mysterious corners of space black holes? Were gravity
• 6:00
  Speaker 1: and space time are so intense that nothing, not even
• 6:04
  Speaker 1: light can escape. Yeah, and they are frustrating to think
• 6:06
  Speaker 1: about and to wonder about because they are They are
• 6:08
  Speaker 1: literally sort of hidden from the universe. They are not
• 6:11
  Speaker 1: just black holes and names. They are actual sort of
• 6:14
  Speaker 1: holes in the fabric of spacetime and reality itself. Yeah,
• 6:17
  Speaker 1: they're almost like a separate universe. They are detached from
• 6:21
  Speaker 1: our universe. Once you fall into a black hole, it's
• 6:23
  Speaker 1: not that you can't escape because you can't go fast
• 6:26
  Speaker 1: enough because the limit of the speed of light. It's
• 6:28
  Speaker 1: because the shape of space is so crazy, so distorted,
• 6:32
  Speaker 1: so curved, that they are one directional, that every path
• 6:36
  Speaker 1: leads you towards the center. So in some sense, everything
• 6:39
  Speaker 1: inside the event horizon is like its own little universe.
• 6:42
  Speaker 1: It's detached from normal space time. Yeah, whatever happens in
• 6:46
  Speaker 1: a black hole stays in a black hole. You can
• 6:48
  Speaker 1: do whatever you want. You can relive your wild days
• 6:51
  Speaker 1: inside of a black hole. That's right, the original Las
• 6:53
  Speaker 1: Vegas and did that Vegas instead of a black hole?
• 6:56
  Speaker 1: If you think about it, at least for people's money
• 6:59
  Speaker 1: and prudence, that's right, it leaves a black hole in
• 7:02
  Speaker 1: their hearts. Yeah, black holes are super mysterious and they
• 7:05
  Speaker 1: seem to sort of occupy a big hole and and
• 7:07
  Speaker 1: people's curiosity. It's one of the things we get asked
• 7:10
  Speaker 1: about the most on our social media and through email.
• 7:13
  Speaker 1: That's right. And it's not just you folks out there
• 7:16
  Speaker 1: who are super curious about black holes and what's inside
• 7:18
  Speaker 1: of them. Professional physicist experts in relativity and quantum mechanics
• 7:23
  Speaker 1: are also desperately curious to know what's inside a black
• 7:27
  Speaker 1: hole because, at their hearts, they might contain the answer
• 7:30
  Speaker 1: to one of the biggest open questions in physics, which
• 7:34
  Speaker 1: is how gravity and quantum mechanics work together, or if
• 7:38
  Speaker 1: they do. Gravity and quantum mechanics are our two pillars
• 7:42
  Speaker 1: of understanding the universe, but they have very very different
• 7:45
  Speaker 1: pictures about how the universe works. But most of the
• 7:48
  Speaker 1: time we only need to use one of them, gravity
• 7:50
  Speaker 1: or quantum mechanics. It's inside a black hole that both
• 7:53
  Speaker 1: of them are needed. But unfortunately we don't really know
• 7:57
  Speaker 1: what they are doing together inside the black hole, because
• 7:59
  Speaker 1: of course it's hidden from us. Yeah, those secrets are
• 8:02
  Speaker 1: locked inside a black holes and we may never get
• 8:05
  Speaker 1: to him because nothing, not even light, escapes a black hole.
• 8:09
  Speaker 1: And yet, somehow ironically or interestingly, black holes are some
• 8:13
  Speaker 1: of the brightest things in the universe. Black holes are
• 8:16
  Speaker 1: not completely dark, that's right, And we hope that by
• 8:19
  Speaker 1: studying what happens outside a black hole, in the neighborhood
• 8:22
  Speaker 1: of a black hole, the things the black hole does
• 8:24
  Speaker 1: to the space and objects around it, perhaps we can
• 8:27
  Speaker 1: start to get a glimmer of what's going on inside.
• 8:30
  Speaker 1: So to be on the program, we'll be asking the
• 8:32
  Speaker 1: question what makes black holes glow interesting? You mean like
• 8:42
  Speaker 1: glow from light or just they just have a positive
• 8:45
  Speaker 1: disposition about their career. Arc is just incredible. They just
• 8:48
  Speaker 1: get bigger and bigger and bigger second and more attention
• 8:53
  Speaker 1: as they go along. That's right. They go from de
• 8:56
  Speaker 1: list to C list, the list and then finally a
• 8:58
  Speaker 1: list as in astronomical st ours. Yeah, not be less
• 9:01
  Speaker 1: like black hole. But yeah, black holes are super interesting
• 9:04
  Speaker 1: because they are mysterious and they trapped even light itself.
• 9:08
  Speaker 1: But also they glow, right, They sort of glow out
• 9:10
  Speaker 1: there in the universe. Sometimes they are even some of
• 9:12
  Speaker 1: the brightest things in the night's time. Yea. And we
• 9:14
  Speaker 1: have been looking at black holes for almost a hundred
• 9:17
  Speaker 1: years without knowing it. Some of the things that we've
• 9:20
  Speaker 1: been studying for decades and decades and decades we only
• 9:22
  Speaker 1: recently discovered are actually black holes. Yeah, so they're not
• 9:26
  Speaker 1: just sort of sitting out there in space sucking stuff
• 9:28
  Speaker 1: up and looking dark and mysterious. They also sort of
• 9:31
  Speaker 1: shine brightly, and at least some of them give off
• 9:33
  Speaker 1: a crazy amount of radiation. That's how we sort of
• 9:37
  Speaker 1: know where they are. So, as usually, we were wondering
• 9:39
  Speaker 1: how many people out there had thought about the glow
• 9:41
  Speaker 1: of black holes, or whether they even knew black holes
• 9:43
  Speaker 1: glowed brightly. So Daniel went out there into the internet
• 9:47
  Speaker 1: to ask people why the black holes glow so brightly.
• 9:50
  Speaker 1: And we are very interested in hearing you speculate without
• 9:53
  Speaker 1: preparation on topics for future episodes. So if you'd like
• 9:57
  Speaker 1: to participate, please send us your name to questions at
• 10:00
  Speaker 1: Daniel and Jorge dot com. We'll send you the questions
• 10:03
  Speaker 1: back over email. You can record the answers in your
• 10:06
  Speaker 1: very own home. It's easy, it's fun. Don't be shy.
• 10:09
  Speaker 1: So pop quiz. Why do you think black holes glow?
• 10:12
  Speaker 1: That's what people had to say. They closer brightly because
• 10:15
  Speaker 1: they're sucking all the surrounding light and everything around it,
• 10:20
  Speaker 1: so you have spires of light basically coming in at
• 10:25
  Speaker 1: one point, and that's why it's so bright. I don't
• 10:29
  Speaker 1: think that the black holes are glowing like itself, definitely
• 10:33
  Speaker 1: not at the center, since there's a gravitation of bood
• 10:36
  Speaker 1: there is so great that not even light can escape it. However,
• 10:40
  Speaker 1: you can potentially detect material around them, and like gas
• 10:44
  Speaker 1: and dust spinning around it, throwing off hot material, and
• 10:49
  Speaker 1: when emitting radiation like X rays and as a matter
• 10:53
  Speaker 1: of falls into the hole, it can be detected and
• 10:56
  Speaker 1: it can actually brightly or glow bright. I think there's
• 11:01
  Speaker 1: so much energy imparted into the material that's swarming around
• 11:05
  Speaker 1: them that um, somehow that energy turns into light excited
• 11:12
  Speaker 1: electrons and stuff like that. And I also know that
• 11:15
  Speaker 1: they can focus material and jetted out, and that material
• 11:20
  Speaker 1: goes out and interacts with the dust and stuff around
• 11:23
  Speaker 1: the black holes and bumps them up into a light
• 11:26
  Speaker 1: emitting excited state like an emission nebula. Okay, so black
• 11:31
  Speaker 1: holes they're not glowing. I think that the light is
• 11:37
  Speaker 1: getting refracted around them, it's getting bounced off, and so
• 11:44
  Speaker 1: it's not the black hole that's glowing. But it's an
• 11:47
  Speaker 1: illusion almost because they're I believe they're called acretion disks,
• 11:52
  Speaker 1: give off just a ton of heat because they're swirling
• 11:56
  Speaker 1: around at almost light speed something like that. I think,
• 12:02
  Speaker 1: not the black hole itself glows. Uh, what it glows
• 12:08
  Speaker 1: would be the creation disks where the older gases a
• 12:13
  Speaker 1: Dutch speed amid energy, and also might be the curs
• 12:20
  Speaker 1: some black holes type qus. That would be also a
• 12:24
  Speaker 1: reason why a black hole looks so brightly. I think
• 12:29
  Speaker 1: this has to deal with black holes that are feeding,
• 12:31
  Speaker 1: that actively feeding off of other stars or other objects.
• 12:34
  Speaker 1: I think when they're feeding, it brings in everything on
• 12:36
  Speaker 1: that creation disk, and everything heats up and creates like
• 12:39
  Speaker 1: plasmas where like they're stripping, you know, stripping everything down
• 12:43
  Speaker 1: to its elemental form. And I think it causes a
• 12:46
  Speaker 1: lot of activity like the electromagnetic field. So like I know,
• 12:50
  Speaker 1: X black holes give off X rays and they give
• 12:53
  Speaker 1: off gamma rays, and they give off these strong energies
• 12:55
  Speaker 1: that we can measure here on Earth. So it has
• 12:57
  Speaker 1: to be because their feet. The black holes give off
• 12:59
  Speaker 1: energy because they're feeding off of surrounding objects and causing
• 13:02
  Speaker 1: a lot of activity in ways that we can measure
• 13:04
  Speaker 1: here on Earth. All Right, some pretty good answers. A
• 13:06
  Speaker 1: lot of people seem to be confident and familiar about
• 13:09
  Speaker 1: this topic, almost like we've been talking about black holes
• 13:11
  Speaker 1: for quite a while, Yeah, for three hundred episodes. It
• 13:16
  Speaker 1: is a popular topic, and a lot of people hit
• 13:18
  Speaker 1: on a really important point, which is that a lot
• 13:21
  Speaker 1: of the radiation from black holes doesn't come from the
• 13:23
  Speaker 1: actual black hole within the event horizon itself, but from
• 13:27
  Speaker 1: the stuff that's around the black hole, the impact of
• 13:30
  Speaker 1: the black hole on the neighboring objects, right, Yeah, or
• 13:33
  Speaker 1: maybe they read both of our books and our two
• 13:36
  Speaker 1: books we have no idea and frequently asked questions about
• 13:38
  Speaker 1: the universe, we do talk about black holes, and and
• 13:41
  Speaker 1: one when we get really into black holes, like literally, Yeah,
• 13:44
  Speaker 1: we talked about what it would be like to fall
• 13:47
  Speaker 1: into a black hole, whether you could survive, and what
• 13:50
  Speaker 1: you should pack along the way and what you experience.
• 13:53
  Speaker 1: So please check out our books, our second book now
• 13:56
  Speaker 1: out frequently asked questions about the universe, but in this
• 13:58
  Speaker 1: case we're talking about why they glow. And a lot
• 14:01
  Speaker 1: of people seem to associated with not the black hole itself,
• 14:05
  Speaker 1: but sort of the things around it, or at least
• 14:07
  Speaker 1: what's happening around it in terms of the space distortion. Yeah,
• 14:10
  Speaker 1: and there's several effects here that are important to pull apart.
• 14:13
  Speaker 1: One is weather black holes actually do glow themselves, and
• 14:17
  Speaker 1: the second are how they make things around them glow.
• 14:21
  Speaker 1: But there's more than just the accretion disc there, which
• 14:23
  Speaker 1: we'll get into later. But first let's talk about the
• 14:25
  Speaker 1: black holes themselves. Most people said black holes don't glow
• 14:29
  Speaker 1: because they're black. That's mostly true, but not actually a
• 14:33
  Speaker 1: hundred percent true. A black hole, even if it had
• 14:36
  Speaker 1: nothing around it, just sitting in empty space, wouldn't be
• 14:39
  Speaker 1: a hundred percent black. They do give off a very
• 14:42
  Speaker 1: small amount of radiation. Yeah, super interesting, and so let's
• 14:47
  Speaker 1: dive into this topic and make it glow. So, Daniel,
• 14:51
  Speaker 1: I guess to refresh everyone out there, what is exactly
• 14:53
  Speaker 1: a black hole. A black hole is a region of
• 14:55
  Speaker 1: space where it is curved so much that not even
• 14:59
  Speaker 1: light can escape. So this portion of space is then
• 15:01
  Speaker 1: encircled by something we call an event horizon. Any object
• 15:05
  Speaker 1: or photon or particle which falls within this event horizon
• 15:09
  Speaker 1: is trapped forever it moves towards the center of the
• 15:12
  Speaker 1: black hole. And this event horizon is not like a
• 15:15
  Speaker 1: physical barrier. There's nothing, there's nobody to greet you or
• 15:19
  Speaker 1: to say hello and welcome to the black hole. It's
• 15:21
  Speaker 1: just sort of a region of space which if you pass,
• 15:24
  Speaker 1: you will never escape. So these black holes are these
• 15:27
  Speaker 1: curved regions of space time, as we said earlier, sort
• 15:29
  Speaker 1: of detached from the rest of the universe, and they
• 15:32
  Speaker 1: form when stars collapse, or sometimes they form at the
• 15:35
  Speaker 1: center of galaxies. And they can be extraordinarily massive. Yeah,
• 15:38
  Speaker 1: and we've talked about how you can have them of
• 15:40
  Speaker 1: any size. You can have tiny, little mini black holes,
• 15:43
  Speaker 1: or you can have giant black holes that are billions
• 15:45
  Speaker 1: of times more massive than our sun. And like you said,
• 15:49
  Speaker 1: there's sort of regions of space where suddenly, like everywhere
• 15:52
  Speaker 1: you can go can only go take you inside of
• 15:55
  Speaker 1: the black hole, right, instead of a weird thing to
• 15:57
  Speaker 1: think about that space can bend that way. Yeah, and
• 15:59
  Speaker 1: space says something you might think of. It's just sort
• 16:01
  Speaker 1: of like the backdrop of the universe, like the stage
• 16:04
  Speaker 1: on which events happen. But we now know that it's
• 16:06
  Speaker 1: much more interesting and it can do fascinating things like
• 16:09
  Speaker 1: bend and twist. Most of the time you don't notice
• 16:12
  Speaker 1: that gravity, turns out is an effect of space is curvature,
• 16:15
  Speaker 1: so you feel that every day when you walk around
• 16:17
  Speaker 1: on the planet. But mostly things seem to move in
• 16:20
  Speaker 1: a way that makes sense to you. But a black
• 16:22
  Speaker 1: holes like the extreme version of that, like crank it
• 16:24
  Speaker 1: up to eleven, where things get really distorted and the
• 16:27
  Speaker 1: shape of space like dominates. You know, it's the thing
• 16:30
  Speaker 1: that determines everything that happens. Right, and I guess specifically
• 16:34
  Speaker 1: you mean like the shape of space time, right, Like
• 16:36
  Speaker 1: maybe it's not so much space but space time, meaning
• 16:39
  Speaker 1: like where you will be in the future in in
• 16:41
  Speaker 1: that space. Yeah, we bundle space and time together into
• 16:44
  Speaker 1: a sort of a four dimensional object. One thing that's
• 16:47
  Speaker 1: really fascinating is that inside the black hole, space becomes
• 16:51
  Speaker 1: one directional. You can only move towards the center of it.
• 16:54
  Speaker 1: That seems a little counter intuitive until you remember that
• 16:57
  Speaker 1: outside the black hole, time is already one direction the
• 17:00
  Speaker 1: way you can only move forwards in time in that
• 17:03
  Speaker 1: same way. Inside the black hole, every path leads towards
• 17:07
  Speaker 1: the center. The future of every particle trajectory inside a
• 17:11
  Speaker 1: black hole hits the singularity. So that's what we mean
• 17:13
  Speaker 1: when we say that space is one directional, and that's
• 17:16
  Speaker 1: directly because space is curved so much so once you're
• 17:20
  Speaker 1: inside of the event of horizon of a black hole,
• 17:22
  Speaker 1: you can't get out, and not even you can't even
• 17:24
  Speaker 1: shoot a laser out of it because the light from
• 17:26
  Speaker 1: the laser, which just should back around and come back
• 17:28
  Speaker 1: to the center of the black hole. And so it's
• 17:30
  Speaker 1: sort of surprising that a black hole can glow then,
• 17:32
  Speaker 1: So like, how do they glow? How can they give
• 17:35
  Speaker 1: off or emit anything? Yeah, black holes can glow, and
• 17:39
  Speaker 1: the way they do that is by Hawking radiation. Hawking
• 17:42
  Speaker 1: radiation is the recognition that black holes have a temperature,
• 17:46
  Speaker 1: like everything else in the universe almost has a temperature.
• 17:49
  Speaker 1: I have a temperature, You have a temperature, the Sun
• 17:51
  Speaker 1: as a temperature, and everything that has a temperature and
• 17:54
  Speaker 1: has electromagnetic interactions glows just sort of like gives off heat.
• 17:59
  Speaker 1: The for example, a pie sitting on your counter cools
• 18:02
  Speaker 1: off it does that by radiating away some of its energy.
• 18:06
  Speaker 1: So this is called black body radiation, and we talked
• 18:08
  Speaker 1: about this on the podcast recently. How everything with a
• 18:11
  Speaker 1: temperature glows. So Stephen Hawking realized that black holes also
• 18:15
  Speaker 1: have a temperature. They're not at absolute zero, which means
• 18:18
  Speaker 1: that they must glow, and so he speculated that they
• 18:21
  Speaker 1: must give off very faint radiation, meaning little particles created
• 18:25
  Speaker 1: just outside the black hole that somehow steals some of
• 18:28
  Speaker 1: its energy. And there are various sort of pop side
• 18:31
  Speaker 1: descriptions of how Hawking radiation happens at the end of
• 18:34
  Speaker 1: a black hole, but it's important to understand that none
• 18:36
  Speaker 1: of those are really very accurate. We have no accurate
• 18:40
  Speaker 1: microscopic picture of how Hawking radiation really happens because it
• 18:44
  Speaker 1: requires the theory of how gravity affects particles, and we
• 18:47
  Speaker 1: just don't have that theory. We don't know what quantum
• 18:50
  Speaker 1: gravity is. We can't describe the effect of gravity on
• 18:53
  Speaker 1: tiny particles. There are some sort of hand wavy explanations
• 18:57
  Speaker 1: to give you a sense of how it works, but
• 18:58
  Speaker 1: it's important to understand that mostly it's a statistical argument
• 19:01
  Speaker 1: about the temperature of black holes, right, Yeah, it's pretty
• 19:04
  Speaker 1: cool to think about hot black holes or cool black holes.
• 19:08
  Speaker 1: But I guess, you know, most people are sort of
• 19:10
  Speaker 1: familiar with a pie in your desk is kind of
• 19:12
  Speaker 1: emanating heat through the air. But I think what's interesting
• 19:15
  Speaker 1: is that even if you put that pot pie out
• 19:17
  Speaker 1: in space where it's not touching any air, it would
• 19:19
  Speaker 1: still radiate heat in the form of infrared light, right, yeah,
• 19:24
  Speaker 1: or visible light depending on the temperature. Like the Sun.
• 19:27
  Speaker 1: There's a huge vacuum between us and the Sun, but
• 19:29
  Speaker 1: it's still able to warm you up on a nice
• 19:31
  Speaker 1: toasty southern California morning, and it does that by radiating
• 19:35
  Speaker 1: away its energy via photons, and the frequency of those
• 19:38
  Speaker 1: photons depends on the temperature of the object. So the
• 19:41
  Speaker 1: Sun glows in the visible spectrum the Earth and you
• 19:44
  Speaker 1: glow in the infrared, as does that pie. Black holes
• 19:48
  Speaker 1: are very very cold, so they glow in very very
• 19:51
  Speaker 1: long wavelengths. Yeah, but it's kind of interesting because you
• 19:55
  Speaker 1: know that hot pie in space is probably you know,
• 19:57
  Speaker 1: the way that it's emanating light is that you know,
• 20:00
  Speaker 1: the electrons and the surface of the pie are excited
• 20:03
  Speaker 1: and they dropped down an energy level maybe and they
• 20:06
  Speaker 1: admit a photon in the infrared, so you can sort
• 20:08
  Speaker 1: of imagine that mechanism for giving off energy. But a
• 20:11
  Speaker 1: black hole is kind of weird, right, because the surface
• 20:14
  Speaker 1: of a black hole is not actually like a surface,
• 20:16
  Speaker 1: and it's not actually like stuff, right. It's weird to
• 20:19
  Speaker 1: think that it can just emanate heat or light out
• 20:22
  Speaker 1: of basically, you know, a hole own space exactly. It
• 20:26
  Speaker 1: is very weird, And as you said, we have a
• 20:28
  Speaker 1: pretty good understanding for how that happens for pies, like
• 20:30
  Speaker 1: the physics of pies, we have a pretty solid understanding,
• 20:33
  Speaker 1: Like quantum pie dynamics pretty well understood, but that's because
• 20:37
  Speaker 1: we understand that kind of matter and the forces of
• 20:40
  Speaker 1: gravity there are pretty weak. But in the case of
• 20:43
  Speaker 1: a black hole, we don't really understand what happens to
• 20:46
  Speaker 1: electrons very very close to the event horizon, or virtual
• 20:50
  Speaker 1: particles created near the event horizon. We just don't have
• 20:53
  Speaker 1: an understanding of it. Neither does Stephen Hawking. He doesn't
• 20:56
  Speaker 1: have a theory of quantum gravity. What he did was
• 20:58
  Speaker 1: make us sort of like semi classical theory of gravity,
• 21:01
  Speaker 1: like a sort of patch together concept of you know,
• 21:04
  Speaker 1: using bits and pieces to sort of approximate what some
• 21:07
  Speaker 1: elements of quantum gravity might look like, and using that
• 21:10
  Speaker 1: you can make a sort of hand wavy picture. You know.
• 21:13
  Speaker 1: The picture is that you have virtual particles created outside
• 21:17
  Speaker 1: the event horizon, not within the black hole, but outside,
• 21:20
  Speaker 1: and those particles can pick up some extra energy because
• 21:23
  Speaker 1: of the incredible gravity of the black hole. Remember that
• 21:26
  Speaker 1: black holes, even though they have this event horizon, they
• 21:29
  Speaker 1: can affect things outside the event horizon. Right, Just like
• 21:32
  Speaker 1: the Sun pulls on you with its gravity from very
• 21:34
  Speaker 1: very far away, a black hole can also do that,
• 21:36
  Speaker 1: pulling on you with its gravity and giving you extra energy.
• 21:40
  Speaker 1: When it does so, it loses that energy. It gives
• 21:43
  Speaker 1: that energy to one of those particles. So if a
• 21:45
  Speaker 1: particles created near a black hole and then boosted by
• 21:49
  Speaker 1: the energy of that black hole, when it leaves, it's
• 21:51
  Speaker 1: taking away some of the energy of that black hole.
• 21:55
  Speaker 1: So again, this is a hand wavy, probably not accurate
• 21:58
  Speaker 1: description of how hawking really is generated because we don't
• 22:01
  Speaker 1: have a solid understanding of quantum mechanics and gravity and
• 22:04
  Speaker 1: how they play well together. All right, well, let's dig
• 22:06
  Speaker 1: into this hawking radiation a little bit more, and then
• 22:09
  Speaker 1: also what are some of the other ways that black
• 22:11
  Speaker 1: holes glow. Some of them are pretty dramatic and maybe
• 22:14
  Speaker 1: even the brightest objects in the universe. So let's get
• 22:17
  Speaker 1: into all that, but first let's take a quick break.
• 22:32
  Speaker 1: All right, we're talking about glowing black holes, which is
• 22:35
  Speaker 1: sort of sounds like an oxymoron, sort of like a
• 22:37
  Speaker 1: bright dark object. I think it's sort of cool that
• 22:39
  Speaker 1: we think about black holes is like hidden and hard
• 22:41
  Speaker 1: to find, and it took us decades to discover them.
• 22:44
  Speaker 1: When it turns out, they're sort of like screaming about
• 22:47
  Speaker 1: their existence all the way through the universe, Like they
• 22:49
  Speaker 1: are not being shot. They're being very very obvious. They're
• 22:52
  Speaker 1: kind of matches. Actually, it's like, can you quiet down, please,
• 22:57
  Speaker 1: we're trying to study black holes. Settle down, settle down.
• 23:00
  Speaker 1: We know you're cool, but you know, you don't need
• 23:02
  Speaker 1: to prove yourself. And that's what makes it ironic is
• 23:05
  Speaker 1: that they are so bright and so intense and so
• 23:07
  Speaker 1: crazy that people sort of overlooked them as candidates for
• 23:11
  Speaker 1: black holes for a long time. Interesting, well, we were
• 23:13
  Speaker 1: talking about hawking radiation, which is sort of the glow
• 23:17
  Speaker 1: or a small glow that black holes have that happens
• 23:20
  Speaker 1: to about the boundary of the black hole due to
• 23:23
  Speaker 1: a quantum particles appearing and things like that. But I
• 23:26
  Speaker 1: guess the question is of all of this is theoretical,
• 23:28
  Speaker 1: we don't actually know how it emits hawking radiation, and
• 23:31
  Speaker 1: I'm guessing we've never seen this hawking radiation being admitted
• 23:34
  Speaker 1: because we barely have pictures of black holes, Like, how
• 23:37
  Speaker 1: do we know hawking radiation is a real thing? How
• 23:39
  Speaker 1: do we know hawking radiation is a real thing? Simple answer,
• 23:42
  Speaker 1: we don't. It's theoretical, it's predicted. It makes more sense
• 23:46
  Speaker 1: than black holes and not giving off hawking radiation because
• 23:49
  Speaker 1: that would require them to be an absolute zero, and
• 23:51
  Speaker 1: it would be in contradiction with lots of things we
• 23:53
  Speaker 1: know about, like entropy. Black holes have to have a
• 23:56
  Speaker 1: temperature because I have to have micro states inside, because
• 23:59
  Speaker 1: they have to receive eve information when something falls into
• 24:02
  Speaker 1: a black hole, they're gathering quantum information, and in order
• 24:06
  Speaker 1: to have that information, they have to have some entropy,
• 24:09
  Speaker 1: and entropy means temperature. So again it's sort of an
• 24:12
  Speaker 1: argument from statistical mechanics. But you're right, we haven't observed
• 24:16
  Speaker 1: it directly, but it's opened up a really rich vein
• 24:19
  Speaker 1: of area for people to explore it's like given us
• 24:21
  Speaker 1: a crack in the facade of black holes where people
• 24:24
  Speaker 1: can jump in and then explore more properties of black holes.
• 24:27
  Speaker 1: But it's not something that we have confirmed experimentally. It's
• 24:31
  Speaker 1: very very faint, really really large black holes emit very
• 24:35
  Speaker 1: very very faint Hawking radiation. It's actually the smaller black
• 24:39
  Speaker 1: holes that emit more Hawking radiation, and they would glow
• 24:42
  Speaker 1: very brightly, and just before a black hole like evaporates
• 24:45
  Speaker 1: into nothingness, it would be quite bright, and we've looked
• 24:48
  Speaker 1: for that, but we haven't seen any evaporating black holes
• 24:51
  Speaker 1: in the universe. I see interesting. So it's sort of
• 24:54
  Speaker 1: theoretical and we think it's sort of glows by this
• 24:57
  Speaker 1: Hawking radiation, but it's sort of what you're saying. It
• 24:59
  Speaker 1: makes ends based on our current theories. But our current
• 25:02
  Speaker 1: theories sort of don't necessarily work inside of a black
• 25:05
  Speaker 1: hole or with a black hole, right, So there might
• 25:07
  Speaker 1: still be surprises about this whole thing. Oh absolutely, our
• 25:10
  Speaker 1: current theories almost certainly wrong. And later somebody smarter, maybe
• 25:15
  Speaker 1: one of our podcast listeners who's going to go into
• 25:17
  Speaker 1: this field, will come along with a full fledged theory
• 25:20
  Speaker 1: of quantum gravity, and it might be that that theory
• 25:23
  Speaker 1: agrees with Hawkings theories and you know this concept of
• 25:26
  Speaker 1: Hawking radiation and black hole temperatures. But it might be
• 25:29
  Speaker 1: that it doesn't and that there are surprises. And that's
• 25:31
  Speaker 1: exactly why we go out and we look at these
• 25:33
  Speaker 1: black holes and we studied them and we take pictures
• 25:35
  Speaker 1: because the universe is filled with surprises and is always
• 25:39
  Speaker 1: confronting us with different stories than the ones we were
• 25:41
  Speaker 1: telling ourselves in our head. Yeah, so it's a hypothetical
• 25:45
  Speaker 1: guest theory based on a theory we think. We know
• 25:48
  Speaker 1: it's wrong. It's what you're saying, also known as doing
• 25:51
  Speaker 1: our best well. Stephen Hawking is usually pretty right about stuff.
• 25:55
  Speaker 1: So these black holes glowing and emanating sort of a
• 25:59
  Speaker 1: slow of heat or radiation is one way that black
• 26:03
  Speaker 1: holes can glow. But they can also glow more dramatically,
• 26:05
  Speaker 1: right like a big time. Yes, they can glow very
• 26:08
  Speaker 1: dramatically because they have very strong effects on the gas
• 26:12
  Speaker 1: around them. The way the black holes grows that they
• 26:14
  Speaker 1: gobble gas and stars in their vicinity and before the
• 26:18
  Speaker 1: things fall into them, they swirl around for a while
• 26:21
  Speaker 1: because they have angular momentum, just the way the Earth
• 26:24
  Speaker 1: is going around the Sun doesn't just fall straight in.
• 26:26
  Speaker 1: Things around a black hole swirl around for a while
• 26:29
  Speaker 1: before they bump into each other and eventually fall in.
• 26:31
  Speaker 1: And that bumping into each other is very intense because
• 26:34
  Speaker 1: the gravity is very intense. So if you have a
• 26:36
  Speaker 1: huge cloud of gas around a black hole, there's a
• 26:39
  Speaker 1: lot of gravitational friction and that heats it up and
• 26:42
  Speaker 1: that glows and they can create incredible sources of light. Yeah,
• 26:47
  Speaker 1: I guess that's kind of maybe hard for people to grasp, right, Like,
• 26:51
  Speaker 1: you know, the Earth is orbiting around the Sun, but
• 26:54
  Speaker 1: we're not sort of glowing or we're not we're not
• 26:56
  Speaker 1: getting sort of shredded and rub into bright bright So
• 27:00
  Speaker 1: maybe is it because black holes are so intense and
• 27:04
  Speaker 1: the gravity around the black holes is like super extra
• 27:07
  Speaker 1: intense that things just get shredded even if they're just
• 27:10
  Speaker 1: going around them. Absolutely, But the Earth does have that
• 27:12
  Speaker 1: effect a little bit, Like the effect of the Moon
• 27:15
  Speaker 1: is to sort of squeeze the Earth a little bit
• 27:18
  Speaker 1: and it like massages the Earth's oceans. Or if you
• 27:20
  Speaker 1: were a moon going around Jupiter for example, Io, why
• 27:24
  Speaker 1: are those moons so hot on the inside because of
• 27:27
  Speaker 1: the gravitational squeezing from Jupiter, and so the Sun is
• 27:31
  Speaker 1: doing that also to the Earth. So if the Sun
• 27:34
  Speaker 1: was larger and more massive and the Earth was closer
• 27:37
  Speaker 1: to it than those tidal forces would really heat up
• 27:40
  Speaker 1: the center of the Earth. And so black holes are
• 27:42
  Speaker 1: much much more intense gravitationally, and these accretion discs are
• 27:45
  Speaker 1: much much closer to them, and so this gravitational sort
• 27:48
  Speaker 1: of squeezing and tugging heats them up. It's more of
• 27:52
  Speaker 1: a gravitational pulling, right, Like the Moon is not so
• 27:55
  Speaker 1: much squeezing the water on Earth, but it's sort of
• 27:57
  Speaker 1: like pulling on it more in one side and the other,
• 28:00
  Speaker 1: and that's what's causing the tidal forces, right. Yeah, Gravity
• 28:04
  Speaker 1: depends very strongly on the distance, and so the bits
• 28:07
  Speaker 1: of the Earth that are closer to the Moon get
• 28:09
  Speaker 1: pulled on harder than the bits of the Earth that
• 28:11
  Speaker 1: are further from the Moon. And so the result is
• 28:13
  Speaker 1: the Moon is basically trying to pull the Earth apart
• 28:16
  Speaker 1: because it's pulling on one side harder than the other side.
• 28:19
  Speaker 1: The same with Jupiter and its moons. You can think
• 28:21
  Speaker 1: of it like taking a piece of chewing gum and
• 28:23
  Speaker 1: pulling on one end only it stretches it out. But
• 28:27
  Speaker 1: then if that chewing gum is spinning, then you're like
• 28:29
  Speaker 1: constantly stretching out different parts of it, so you're keeping
• 28:32
  Speaker 1: it warm. You're you're like massaging it like a dough,
• 28:34
  Speaker 1: like if you need a dough. It it sort of
• 28:36
  Speaker 1: heats up a little bit, right, and now it's spinning
• 28:38
  Speaker 1: like a pizza dough where we're a little hungry here.
• 28:42
  Speaker 1: I don't know if you can tell. So that's what's
• 28:44
  Speaker 1: kind of what's happening to things around a black hole.
• 28:46
  Speaker 1: They're getting kind of like stretched a lot by this
• 28:49
  Speaker 1: the intense gravitational forces, but they're also it also sort
• 28:52
  Speaker 1: of happens not just because of the tidal forces, but
• 28:54
  Speaker 1: just because it's going so fast around the black hole, right,
• 28:57
  Speaker 1: because things get sucked in pretty fast, pending on how
• 29:00
  Speaker 1: fast the black hole is spinning and this stuff around
• 29:02
  Speaker 1: it is spinning, absolutely, it can get going pretty fast,
• 29:05
  Speaker 1: just like a figure skater speeds up and spins faster
• 29:09
  Speaker 1: if she pulls in her arms because of conservation of
• 29:12
  Speaker 1: angle momentum, or just the way like comets as they
• 29:14
  Speaker 1: approach the Sun from the outer Solar System get going
• 29:17
  Speaker 1: really really fast as you fall in towards the center
• 29:21
  Speaker 1: of the black hole. Then you go faster and faster
• 29:24
  Speaker 1: both in spin and in velocity. So you get a
• 29:27
  Speaker 1: lot of particles moving really really fast, bumping into each other.
• 29:30
  Speaker 1: And that's what temperature is. Temperature is basically like spedometer
• 29:34
  Speaker 1: of particles, right, right, So thanks are crazy spinning around
• 29:37
  Speaker 1: a black hole, and so somehow that gives us energy,
• 29:40
  Speaker 1: right like things are getting pulled apart, rubbing, exploding, crashing,
• 29:43
  Speaker 1: and that just gives us a lot of light and radiation. Yeah,
• 29:47
  Speaker 1: like we said before, things that are hot, they glow,
• 29:49
  Speaker 1: and so this gas is super duper hot, and so
• 29:52
  Speaker 1: it glows in the X ray gives us these very
• 29:54
  Speaker 1: very powerful X ray radiation, which is just another kind
• 29:57
  Speaker 1: of photon, just much higher fe quency. Yeah, pretty close.
• 30:01
  Speaker 1: And so for a long time we thought that these
• 30:02
  Speaker 1: glowing black holes were actually stars. Right. In fact, we
• 30:06
  Speaker 1: call them quasi stars. Yeah, they've been seen since the
• 30:10
  Speaker 1: early parts of last century. In the nineteen fifties, they
• 30:13
  Speaker 1: started to study them more intensely, but they didn't really
• 30:15
  Speaker 1: understand what they were because they were very very bright,
• 30:19
  Speaker 1: but their spectrum was very very weird, Like if you
• 30:22
  Speaker 1: look at the frequency of the light that they emitted,
• 30:24
  Speaker 1: it didn't match what typical stars emitted. They looked like
• 30:28
  Speaker 1: they were a red shifted super duper far like the
• 30:31
  Speaker 1: photons were shifted really far down in wavelength compared to
• 30:35
  Speaker 1: most stars. And usually when that happens, it means that
• 30:38
  Speaker 1: the thing you're looking at is really really far away,
• 30:41
  Speaker 1: so it's moving away from you quickly. That's how we
• 30:43
  Speaker 1: measured the distance to things sometimes so that we measured
• 30:46
  Speaker 1: this red shift. But in this case, these red shifts
• 30:48
  Speaker 1: were super dramatic, and yet the objects were really bright,
• 30:51
  Speaker 1: and so at first glance it seems like something which
• 30:54
  Speaker 1: is really bright and also crazy far away, which means
• 30:57
  Speaker 1: it must be like riduculously bright. So first atronomers were
• 31:00
  Speaker 1: really scratching their heads wondering what these things were interesting
• 31:04
  Speaker 1: like to the naked eye, and when when you look
• 31:05
  Speaker 1: up at the night sky, it just looks like a
• 31:07
  Speaker 1: little pin bright pin point, But when you look at
• 31:09
  Speaker 1: the like the frequency of the light, it actually tells
• 31:12
  Speaker 1: you that it's crazy bright and crazy far. Yeah, they
• 31:14
  Speaker 1: can be like a hundred times brighter than the other
• 31:17
  Speaker 1: galaxies near them. So people like, what's going on? How
• 31:20
  Speaker 1: are these things so bright? Because they're already really really
• 31:23
  Speaker 1: far away, these things, like just to get a scale,
• 31:26
  Speaker 1: you know, these things like at their source would have
• 31:29
  Speaker 1: to be like four trillion times brighter than the sun,
• 31:32
  Speaker 1: like at the same distance. And so then it turned
• 31:35
  Speaker 1: out that those are actually black holes, that the ones
• 31:38
  Speaker 1: that we saw in this guy that were so bright
• 31:40
  Speaker 1: and so far so people saw these before black holes
• 31:43
  Speaker 1: were really taken seriously as an astronomical object, and so
• 31:45
  Speaker 1: it took a few decades for people to sort of
• 31:47
  Speaker 1: put those two puzzles together. You know, what are these
• 31:50
  Speaker 1: quasars and also our black holes? Real people put that together, like, wow,
• 31:54
  Speaker 1: black holes. Maybe that's what these things are. Maybe they
• 31:57
  Speaker 1: are powering these quasars. And they came all together when
• 32:01
  Speaker 1: people started studying like the size of these quasars. One
• 32:04
  Speaker 1: thing that's really interesting about them is that quasars are
• 32:06
  Speaker 1: highly variable. They don't just like burn brightly all the time.
• 32:10
  Speaker 1: That's because the gas around the black hole is really volatile.
• 32:13
  Speaker 1: But if the brightness is varying, like over a few days,
• 32:16
  Speaker 1: that actually tells you something about the size of the object,
• 32:19
  Speaker 1: because it means it can only be like a few
• 32:21
  Speaker 1: light days across. It can't be really really large and
• 32:25
  Speaker 1: also like coherently varying in time very quickly, and so
• 32:29
  Speaker 1: that tells you that it's really small and also really intense.
• 32:32
  Speaker 1: It takes a lot of mass to power all that brightness,
• 32:36
  Speaker 1: So that's when people start to realize maybe these things
• 32:38
  Speaker 1: are powered by black holes. You're saying that if something
• 32:41
  Speaker 1: is that bright and if it's large, it wouldn't be
• 32:45
  Speaker 1: you know, changing in terms of the light it gives up.
• 32:48
  Speaker 1: You can't have two things that are like a light
• 32:50
  Speaker 1: year apart, coherently varying in time, like having the same
• 32:53
  Speaker 1: pattern over in just a few days, because they have
• 32:56
  Speaker 1: to be somehow communicating with each other. But they are
• 32:58
  Speaker 1: light year apart, so they can't. So if two things
• 33:00
  Speaker 1: are in sync over a period of like a day
• 33:03
  Speaker 1: or an hour, then they have to be within a
• 33:04
  Speaker 1: light day or a light hour of each other if
• 33:07
  Speaker 1: the same process is driving them. So it's like a
• 33:09
  Speaker 1: cool indirect way to get a sense of the size
• 33:11
  Speaker 1: of an object by seeing how quickly it's light varies. Interesting,
• 33:16
  Speaker 1: I guess the speed of light limits even like how
• 33:19
  Speaker 1: fast you can coordinate different parts of a bright object.
• 33:22
  Speaker 1: It's kind of what you're saying, you know, if they're
• 33:24
  Speaker 1: driven by the same fundamental mechanism. They have the same
• 33:26
  Speaker 1: underlying cause, like two sides of an object grow brighter
• 33:30
  Speaker 1: or darker because of the same underlying physics that's happening
• 33:33
  Speaker 1: inside of it. Then they can't be that far apart.
• 33:35
  Speaker 1: So you concluded, well, this must be something super bright,
• 33:38
  Speaker 1: super far and also super small, or at least, you know,
• 33:42
  Speaker 1: at least the size of like the our solar system
• 33:44
  Speaker 1: or a sun exactly. And another interesting piece of the
• 33:47
  Speaker 1: puzzle is that we mostly see them really far away. Right,
• 33:51
  Speaker 1: we said earlier that we see them really high red shifts,
• 33:54
  Speaker 1: which means they're mostly far away. And you might wonder, like, well,
• 33:57
  Speaker 1: if these things are really bright, shouldn't we see a
• 33:59
  Speaker 1: bunch of them close are up that are like obviously
• 34:01
  Speaker 1: really really bright. But the thing is that these things
• 34:04
  Speaker 1: were made mostly in the early part of the universe's history,
• 34:07
  Speaker 1: like around three billion years was the peak time to
• 34:10
  Speaker 1: make these quasars, and since then we haven't really been
• 34:13
  Speaker 1: making them very much anymore. So most of the quasars
• 34:16
  Speaker 1: in the universe are far away from us because the
• 34:18
  Speaker 1: ones close by have already died out. They don't last
• 34:21
  Speaker 1: that long. They only last like ten or twenty million years.
• 34:24
  Speaker 1: I guess what you're saying is that, you know, not
• 34:26
  Speaker 1: all black holes have an accretion disc or like stuff
• 34:30
  Speaker 1: blowing brightly around them. And so the ones that we
• 34:33
  Speaker 1: that do seem to have that we can see are
• 34:36
  Speaker 1: probably old because it's probably the black holes are closer
• 34:39
  Speaker 1: to us. I've already burrowed out their accretion disk. Yes,
• 34:42
  Speaker 1: And it's not something that we understand very well because
• 34:45
  Speaker 1: we'll talk about a bit more later, like what's going
• 34:47
  Speaker 1: on very close to the black hole, how they gather
• 34:50
  Speaker 1: gas and how they blow that gas away due to
• 34:52
  Speaker 1: the intense radiation is not something that's currently very well understood.
• 34:57
  Speaker 1: We think that about five to ten of galaxies with
• 35:00
  Speaker 1: black holes at their core have quaisars. So a lot
• 35:03
  Speaker 1: of the galaxies around us that have black holes don't
• 35:06
  Speaker 1: have a quasar. Its requires like sort of special conditions.
• 35:09
  Speaker 1: Not every single one does it right, or maybe they did,
• 35:11
  Speaker 1: but they it's no longer kind of burning bright. Yeah,
• 35:14
  Speaker 1: if they grew to a certain size and they've blown
• 35:17
  Speaker 1: away a lot of the gas that they would otherwise feed.
• 35:19
  Speaker 1: Remember we had another episode about how you could quickly
• 35:22
  Speaker 1: make a black hole, and it's not actually that easy
• 35:24
  Speaker 1: to just like dump a lot of stuff into a
• 35:26
  Speaker 1: black hole, because as they grow, their gravity gets stronger
• 35:31
  Speaker 1: and they create this intense radiation which actually works against
• 35:34
  Speaker 1: them because it blows away a lot of the stuff nearby. Interesting,
• 35:38
  Speaker 1: it's like it it gets indigestion, you get you get
• 35:41
  Speaker 1: a feed it slowly. You gotta burp your black hole
• 35:44
  Speaker 1: just right, yea, otherwise still burp other things out. So
• 35:47
  Speaker 1: then that's kind of so we don't see quasars near us,
• 35:51
  Speaker 1: meaning black holes that blow brightly, but they are out there,
• 35:54
  Speaker 1: and they do it through this kind of mechanism of
• 35:56
  Speaker 1: the acreation, this burning stuff up, crashing it around itself.
• 36:00
  Speaker 1: And also sometimes that radiation can be very focused, right,
• 36:03
  Speaker 1: in which case we get super extra bright quasars. Yeah,
• 36:07
  Speaker 1: if quasars happen to be pointed right at us or
• 36:09
  Speaker 1: they're moving towards us, that we call them blaze ours
• 36:13
  Speaker 1: because their radiation gets boosted by being pointed right at us. Right.
• 36:16
  Speaker 1: But I guess this is a kind of a subtle
• 36:18
  Speaker 1: point is that sometimes in a black hole, the ecreation
• 36:21
  Speaker 1: disc is glowing. It's bright, we can see it from
• 36:23
  Speaker 1: far away. And sometimes but sometimes it's sort of aligned
• 36:26
  Speaker 1: in the right way where it's super extra bright. Right, Yeah,
• 36:29
  Speaker 1: if it's lined up directly to Earth, like the most
• 36:31
  Speaker 1: intense part of the quasar mission is pointing right at
• 36:34
  Speaker 1: the Earth, then they get super extra bright. Does that
• 36:38
  Speaker 1: mean that all quasars are all glowing? Accretion discs are directional,
• 36:42
  Speaker 1: like they all sort of point in a particular way
• 36:45
  Speaker 1: like a flashlight. They do, but not that intensely. They're
• 36:47
  Speaker 1: not like extremely focused the way like a pulsar is
• 36:50
  Speaker 1: a pulsar, you just won't even see that radiation if
• 36:53
  Speaker 1: it's not pointed at the Earth. These are not as directional.
• 36:56
  Speaker 1: But if the intense part of it is pointed at
• 36:58
  Speaker 1: the Earth, then yeah, there's an enhancement factor there. But
• 37:01
  Speaker 1: black holes do have another way that they glow, which
• 37:04
  Speaker 1: is very pointed. Oh yeah, what is that? Well, on
• 37:07
  Speaker 1: top of the accretion disc, they also sometimes create these
• 37:10
  Speaker 1: incredible jets of matter which fly out from the poles
• 37:15
  Speaker 1: of the black hole, both sort of north and south,
• 37:18
  Speaker 1: and these things are really extraordinary. So some black holes
• 37:20
  Speaker 1: don't have an increation disc, some of them do. It's glowing,
• 37:24
  Speaker 1: it's glowing in a sort of general direction, and some
• 37:26
  Speaker 1: of them are even more focused what you're saying, like,
• 37:29
  Speaker 1: somehow this accretion disk gathers things and shoots it in
• 37:32
  Speaker 1: one way, sort of like a like a tornado. Sort
• 37:35
  Speaker 1: of like a tornado. Some of these black holes have
• 37:38
  Speaker 1: these incredible things we call jets, which shoot out photons
• 37:41
  Speaker 1: and other kinds of matter, really really long jets, like
• 37:45
  Speaker 1: much larger than the black hole itself. For example, some
• 37:48
  Speaker 1: of these jets are like five thousand to a hundred
• 37:51
  Speaker 1: thousand light years long. Whoa, and so what do they
• 37:55
  Speaker 1: look like? They sort of look like a spotlight shining
• 37:57
  Speaker 1: out into the night skuy kind of, yeah, you can
• 38:00
  Speaker 1: you like a little dot from the quas are at
• 38:01
  Speaker 1: the core, and then you see these incredibly long rays
• 38:05
  Speaker 1: which shoot out into the interstellar medium. And because that
• 38:08
  Speaker 1: then hit stuff like gas and dust, they can create
• 38:11
  Speaker 1: these big shock waves. And so you can google a
• 38:14
  Speaker 1: picture of like astrophysical jets. But they look like these
• 38:17
  Speaker 1: incredible fireballs shooting out both sides of the black hole,
• 38:21
  Speaker 1: and they're much much bigger than the actual extent of
• 38:24
  Speaker 1: the black hole. One astronomer described as like seeing the
• 38:28
  Speaker 1: statue of Liberty popping out of a marble. Decide to
• 38:32
  Speaker 1: see but you're saying, we don't really understand how these
• 38:35
  Speaker 1: jets are formed, right, Like I imagine they're creating. This
• 38:38
  Speaker 1: is stuff kind of orbiting around the black hole, waiting
• 38:40
  Speaker 1: to fall into the black hole. So how does stuff
• 38:42
  Speaker 1: actually kind of pop out. It's all connected into this
• 38:45
  Speaker 1: question of how stuff falls into the black hole and
• 38:48
  Speaker 1: what happens. But we think that a lot of black
• 38:50
  Speaker 1: holes are not just curved regions of space time. They're
• 38:53
  Speaker 1: also spinning, and also they probably have electric charge, and
• 38:57
  Speaker 1: those are the three things that black holes can have
• 39:00
  Speaker 1: ass spin, and charge. And if a black hole has
• 39:03
  Speaker 1: electric charge and it's spinning, then it also has a
• 39:06
  Speaker 1: very very powerful magnetic field, and that magnetic field will
• 39:09
  Speaker 1: direct the path of particles just the same way that
• 39:12
  Speaker 1: the Earth's magnetic field changes how the solar wind hits
• 39:15
  Speaker 1: the Earth. Most of those particles don't end up coming
• 39:18
  Speaker 1: down and hitting us. They spiral around magnetic field lines
• 39:22
  Speaker 1: and go to the north pole or the south pole,
• 39:24
  Speaker 1: and that's what the northern lights are. In the same way,
• 39:27
  Speaker 1: this incredibly intense magnetic field of a black hole, some
• 39:30
  Speaker 1: of these particles, which otherwise might have fallen into the
• 39:32
  Speaker 1: black hole gets sort of like funneled up and shot
• 39:35
  Speaker 1: out the top or the bottom of the black hole. Interesting,
• 39:39
  Speaker 1: it's sort of channeled by this magnetic field. But I
• 39:41
  Speaker 1: guess the question is how does a black hole get
• 39:43
  Speaker 1: a charge? Like, does it because it absorbs more electrons
• 39:46
  Speaker 1: than than positive charges? Or how does it get a charge? Yeah,
• 39:50
  Speaker 1: we think that charge is conserved in the universe. And
• 39:52
  Speaker 1: so if you have a black hole that's neutral and
• 39:55
  Speaker 1: you toss an electron into it, that black hole now
• 39:57
  Speaker 1: has a charge, and you can't like tell where the
• 40:00
  Speaker 1: electron is inside the event horizon. All you can tell
• 40:03
  Speaker 1: is that the black hole itself is now charged. And
• 40:06
  Speaker 1: so any black hole which eats more positive than negative
• 40:09
  Speaker 1: particles will have a positive charge. And the same is
• 40:11
  Speaker 1: true for the opposite scenario. So somehow the black hole
• 40:14
  Speaker 1: ate more electrons then and then then post trons, And
• 40:18
  Speaker 1: we do have an asymmetry in our universe right. There
• 40:20
  Speaker 1: are a lot more electrons out there than positrons, and
• 40:23
  Speaker 1: stars and other matter have more electrons in them than positrons,
• 40:27
  Speaker 1: while they are also protons in there to balance things out.
• 40:30
  Speaker 1: The matter antimatter asymmetry the universe means that there are
• 40:33
  Speaker 1: lots of these charge particles sloating around for black holes
• 40:35
  Speaker 1: to gobble up. Interesting, that's true for the whole universe.
• 40:38
  Speaker 1: You're saying the whole universe has a negative charge. Well,
• 40:41
  Speaker 1: that's a really fun question. What is the charge of
• 40:43
  Speaker 1: the whole Is it positive, is it negative? Is it
• 40:46
  Speaker 1: an optimist, is it a pessimist. That's a really cool question.
• 40:50
  Speaker 1: I think that if charge has always been conserved, then
• 40:53
  Speaker 1: the universe must have the same charge it had early on,
• 40:56
  Speaker 1: And so if it came from like an in phloton
• 40:59
  Speaker 1: field or something that we've discussed recently, it probably has
• 41:01
  Speaker 1: an overall zero charge. But in the end those charges
• 41:05
  Speaker 1: break up into electrons and protons and other kinds of particles,
• 41:08
  Speaker 1: some of which might be more likely to be eaten
• 41:11
  Speaker 1: and by black holes. But they're also just there are
• 41:13
  Speaker 1: patches throughout the universe is not completely smooth, and so
• 41:16
  Speaker 1: in the same way that like black holes spin because
• 41:18
  Speaker 1: there's angular momentum. Even if the total spin of the
• 41:22
  Speaker 1: universe is zero, there are patches of it that's spin
• 41:24
  Speaker 1: left or spin right. In the same way there are
• 41:26
  Speaker 1: patches of the universe that have more matter or less matter.
• 41:29
  Speaker 1: There probably are patches of the universe that have like
• 41:31
  Speaker 1: more positive charge and more negative charge, and so black
• 41:34
  Speaker 1: holes end up accumulating some charge. Like the chances of
• 41:37
  Speaker 1: getting exactly zero charge if you have you know, ten
• 41:41
  Speaker 1: to the fifty particles is like the chances of flipping
• 41:44
  Speaker 1: a coin tend to the fifty times and getting exactly heads.
• 41:49
  Speaker 1: It's very unlikely. Yeah, it seems like it. So you're
• 41:52
  Speaker 1: if you're a black hole, you could be team positive
• 41:54
  Speaker 1: or team negative. There's two teams exactly probably very few
• 41:58
  Speaker 1: black holes like exactly on that knife's edge, and as
• 42:02
  Speaker 1: a result, they get very strong magnetic fields, right, and
• 42:04
  Speaker 1: so that's kind of the most intense way that a
• 42:07
  Speaker 1: black hole can glow, although it's technically not glowing. It's
• 42:10
  Speaker 1: just kind of redirecting and swirling and igniting the stuff
• 42:14
  Speaker 1: around it and then shooting it in one particular direction. Yeah,
• 42:17
  Speaker 1: and so these astrophysical jets are super fascinating and really
• 42:21
  Speaker 1: a source of research right now. People trying to use
• 42:24
  Speaker 1: them to understand what happens to a particle as it
• 42:27
  Speaker 1: falls into a spinning, electrically charged black hole, whether it
• 42:30
  Speaker 1: gets repelled by the magnetic field of the black hole,
• 42:33
  Speaker 1: or whether it gets sucked in all this kind of
• 42:35
  Speaker 1: stuff that must be pretty cool to think about and model.
• 42:38
  Speaker 1: All right, well, let's get into what happens if you
• 42:41
  Speaker 1: focus one of these jets on Earth. Is it good
• 42:43
  Speaker 1: news or bad news? And let's talk about our most
• 42:46
  Speaker 1: recent pictures of black holes. But first let's take another
• 42:49
  Speaker 1: quick break. All right, we're talking about glowing black holes,
• 43:04
  Speaker 1: and this is, I guess a pretty glowing reveal of
• 43:06
  Speaker 1: black holes. Would you say that we can black holes
• 43:09
  Speaker 1: five stars absolutely, or a million stars sometimes the trillion stars,
• 43:13
  Speaker 1: who knows. So sometimes they admit these intense jets, and
• 43:16
  Speaker 1: that's when they really shine in the sky, but they
• 43:18
  Speaker 1: can be sort of dangerous, right, like if black hole
• 43:20
  Speaker 1: suddenly focus its jet on us, we it might fry
• 43:24
  Speaker 1: us kind of right. Yes, these are very intense sources
• 43:27
  Speaker 1: of radiation. Fortunately none of them are shined at Earth
• 43:30
  Speaker 1: right now because they go really, really far. And the
• 43:33
  Speaker 1: black hole is the center of our galaxy, which is
• 43:35
  Speaker 1: like one that might be capable of creating very intense radiation.
• 43:39
  Speaker 1: We don't think that it has any of these jets.
• 43:41
  Speaker 1: It might have very small ones, but we're not sure.
• 43:44
  Speaker 1: We're going to try to take a picture of it soon. Well,
• 43:46
  Speaker 1: it's sort of sad that black holes are getting their
• 43:48
  Speaker 1: jet packs before humans are. But we we do have
• 43:51
  Speaker 1: sort of photos of black holes glowing like it's not
• 43:54
  Speaker 1: just something that we're posting or wondering about. We do
• 43:57
  Speaker 1: have a more recent pictures black holes, right, and you
• 44:01
  Speaker 1: can see them going. Yeah. Several years ago, they tied
• 44:04
  Speaker 1: together a bunch of radio telescopes around the world into
• 44:07
  Speaker 1: sort of like a huge meta telescope, and by taking
• 44:11
  Speaker 1: data together for about ten days, different parts of the Earth,
• 44:15
  Speaker 1: all working together, all pointed at the same black hole,
• 44:17
  Speaker 1: they were able to sort of tie those together into
• 44:20
  Speaker 1: a radio telescope effectively the size of the Earth. This
• 44:23
  Speaker 1: is called the event Horizon telescope. And they took data
• 44:27
  Speaker 1: for about ten days and then crunched it with their
• 44:29
  Speaker 1: computers for like two years. And in April two thousand nineteen,
• 44:33
  Speaker 1: they put out what was called the first direct image
• 44:36
  Speaker 1: of a black hole. And you might remember it. It It
• 44:37
  Speaker 1: looks sort of like a glowing donut. Yeah, So you
• 44:40
  Speaker 1: can google this and and image and do an image
• 44:42
  Speaker 1: starch where I guess what would you start for black
• 44:45
  Speaker 1: hole photo? Yeah, black hole photo. Absolutely, that pops right
• 44:48
  Speaker 1: up and so you can see you can see sort
• 44:50
  Speaker 1: of the dark circle in the middle of the glowing disk,
• 44:52
  Speaker 1: and it's sort of skewed though, right, It's it's not
• 44:55
  Speaker 1: like a perfectly round donut. It's sort of skewed one
• 44:57
  Speaker 1: in one direction. Yeah, it's like a crispy cream you're
• 45:00
  Speaker 1: of angling in at as you're about to take your
• 45:02
  Speaker 1: first bite, got kind of squished on one side. And
• 45:06
  Speaker 1: once you're looking at their the glow, of course, is
• 45:08
  Speaker 1: not from the actual black hole. You're not seeing hawking radiation.
• 45:12
  Speaker 1: You're seeing the glow of the accretion disk. And that
• 45:15
  Speaker 1: black hole is M eight seven. It's at the center
• 45:17
  Speaker 1: of a galaxy that's about fifty five million light years away,
• 45:21
  Speaker 1: but they chose it because it's incredibly powerful black hole.
• 45:25
  Speaker 1: There's like six point five billion solar masses inside of it. Wow,
• 45:29
  Speaker 1: six point five billion times the mass of our Sun.
• 45:33
  Speaker 1: And it's a fairly close enough for us to sort
• 45:36
  Speaker 1: of look at it. And so we have a picture
• 45:38
  Speaker 1: of its accretion disk, and there's sort of different theories
• 45:41
  Speaker 1: about what's going on there, that's right, And so the
• 45:43
  Speaker 1: first picture just sort of like give us the first glance,
• 45:46
  Speaker 1: and we saw the accretion disk, we saw the glow.
• 45:48
  Speaker 1: We confirmed what we thought you see the hole in
• 45:50
  Speaker 1: the center of it, which is the event horizon, and
• 45:52
  Speaker 1: that's about as big as we expected it to be.
• 45:55
  Speaker 1: It's really incredibly huge though, Like that event horizon is
• 45:58
  Speaker 1: larger than the radius of Pluto. Like that black hole
• 46:01
  Speaker 1: is a monster wow, meaning like you could sit in
• 46:05
  Speaker 1: inside of our solar system and it would basically take
• 46:07
  Speaker 1: take over the whole solar system. It would take over
• 46:09
  Speaker 1: the whole solar system exactly. And recently what they've done
• 46:13
  Speaker 1: is they've studied that data in more detail. They went
• 46:16
  Speaker 1: back and they reanalyze the data trying to get more
• 46:18
  Speaker 1: information about what's swirling around inside that acretion disk. Because
• 46:23
  Speaker 1: what they did at first, we just sort of like
• 46:25
  Speaker 1: look at the photons and gather them and say where
• 46:27
  Speaker 1: is it bright, where is it not that bright? And
• 46:29
  Speaker 1: that's the picture that you see is like an intensity
• 46:31
  Speaker 1: map essentially shows you where it's glowing hot and where
• 46:34
  Speaker 1: it's not glowing as much. What they did now is
• 46:36
  Speaker 1: they went back and they analyzed it to see how
• 46:38
  Speaker 1: those photons are polarized. Like photons when they move through
• 46:42
  Speaker 1: space can do so in various ways, like we sometimes
• 46:45
  Speaker 1: talk about how electrons have spin, spin up or spin down.
• 46:48
  Speaker 1: Photons also have spin, so they don't just fly through
• 46:51
  Speaker 1: space with energy. They can also spin in various ways
• 46:54
  Speaker 1: you might be familiar with, like sunglasses that filter out
• 46:57
  Speaker 1: polarized light, for example, and so like comes in sort
• 47:00
  Speaker 1: of different spins. And what they did is they looked
• 47:02
  Speaker 1: at the photons and counted how many spin in different ways,
• 47:06
  Speaker 1: because this tells you something really interesting about the magnetic
• 47:09
  Speaker 1: field inside that accretion disk, which affects how photons spin.
• 47:14
  Speaker 1: It's like you're you're looking at for extra information in
• 47:18
  Speaker 1: the light that they might tell you what's going on,
• 47:19
  Speaker 1: because we we don't understand it right exactly. It's like
• 47:22
  Speaker 1: you first had a black and white picture, and now
• 47:24
  Speaker 1: you're looking at the different colors, right, You're looking for
• 47:27
  Speaker 1: extra information, new dimensions to this. So they crunched the
• 47:30
  Speaker 1: same picture, the same data through their computers for another
• 47:33
  Speaker 1: two years, and now they have an updated photograph. And
• 47:36
  Speaker 1: this one looks quite different because it's still the acreation disc.
• 47:39
  Speaker 1: But you can see these stripes. You can see these
• 47:42
  Speaker 1: like twists, this spiral pattern that tells you sort of
• 47:45
  Speaker 1: where the magnetic field is in the accretion disk and
• 47:48
  Speaker 1: sort of what its intensity. Is interesting, like the whole
• 47:52
  Speaker 1: disc has a magnetic field or there's like variations in
• 47:55
  Speaker 1: the field all around their variations in the field, and
• 47:58
  Speaker 1: from the pattern of where the hootons are and how
• 48:01
  Speaker 1: they are polarized, you can get a sense for the
• 48:03
  Speaker 1: strength of the magnetic field and like how those magnetic
• 48:05
  Speaker 1: field lines look, which tells you a lot about how
• 48:08
  Speaker 1: things must be moving inside the accretion disk, because those
• 48:11
  Speaker 1: very intensive magnetic fields are sort of like funneling particles.
• 48:14
  Speaker 1: They're telling particles where they can and can't go. Interesting,
• 48:18
  Speaker 1: like you're looking at the texture of the accretion disk. Yeah,
• 48:21
  Speaker 1: and so there are two theories about what's going on there,
• 48:23
  Speaker 1: and they have pretty fun acronyms matt and sane. It's
• 48:27
  Speaker 1: either crazy black hole or or a reasonable black hole.
• 48:31
  Speaker 1: Reasonable black Yeah. People were wondering how this works, and
• 48:34
  Speaker 1: they developed these different models for how things in the
• 48:37
  Speaker 1: acretion disk gets sort of slurped up by the magnetic
• 48:40
  Speaker 1: fields and then shot into this helix which pushes them
• 48:43
  Speaker 1: out into this astrophysical jet. Like how do particles when
• 48:46
  Speaker 1: they fall in through the accretion disk, how do they
• 48:48
  Speaker 1: sort of miss falling into the black hole and end
• 48:50
  Speaker 1: up pumped out into this incredibly long death ray through space.
• 48:54
  Speaker 1: So first people thought like, mostly it's just sort of
• 48:57
  Speaker 1: crazy and turbulent that you don't have really intense magnetic fields,
• 49:02
  Speaker 1: but that stuff just sort of like falls into the
• 49:04
  Speaker 1: center and the accretion disc sort of controls the helix.
• 49:07
  Speaker 1: That it's an angular momentum is sort of what's driving
• 49:10
  Speaker 1: the spinning of everything, and that the helix sort of
• 49:12
  Speaker 1: forms eventually from that spin. That was the model they
• 49:16
  Speaker 1: call sane stable and normal evolution s a n E.
• 49:20
  Speaker 1: And then there was a competing model they call MAD
• 49:23
  Speaker 1: for magnetically arrested disk. This is a model for what
• 49:27
  Speaker 1: happens if you like really crank up the magnetic fields,
• 49:30
  Speaker 1: like really strong, powerful magnetic fields, so that they're sort
• 49:34
  Speaker 1: of in control. And what happens there is that you
• 49:37
  Speaker 1: expect like coherent channels of particles. You expect like tubes
• 49:41
  Speaker 1: of particles being funneled by this magnetic field really quickly
• 49:45
  Speaker 1: wrapping up into a very powerful helix. And it also
• 49:48
  Speaker 1: predicts more polarized light because of these strong magnetic fields. Interesting,
• 49:53
  Speaker 1: it's like we know that there's an acreation disk, but
• 49:55
  Speaker 1: we don't know what's kind of dominating the way it works.
• 49:58
  Speaker 1: It's gravity, is it magnetic fields? And it sounds like
• 50:01
  Speaker 1: it's mostly magnetic fields or or at least they play
• 50:03
  Speaker 1: a huge part that we didn't think about before. Yeah,
• 50:06
  Speaker 1: and so this updated picture that shows us the polarization
• 50:09
  Speaker 1: of the photons, it helps us determine which of these
• 50:11
  Speaker 1: two models is accurate. And so the data supports that
• 50:15
  Speaker 1: black holes are mad rather than sane, that they have
• 50:18
  Speaker 1: really intense magnetic fields, and that that's what's creating this helix,
• 50:22
  Speaker 1: and that's what pulling the particles out of the increation
• 50:24
  Speaker 1: disk and then into this jet that reaches out through space.
• 50:27
  Speaker 1: But what do you think make the mad of not
• 50:30
  Speaker 1: getting enough attention? It's because they got overcharged. Nice, they
• 50:37
  Speaker 1: stop being positive. Exactly. You eat too many electrons and
• 50:41
  Speaker 1: you end up feeling kind of negative. Yeah, they had
• 50:43
  Speaker 1: a negative experience, for sure. Now they're mad. They lost
• 50:46
  Speaker 1: their sanity. There you go, exactly. And so it's it's
• 50:50
  Speaker 1: cool because it's the first time we've really seen something
• 50:52
  Speaker 1: about the dynamics of the increation disk. Before we saw
• 50:55
  Speaker 1: sort of like a static image like Okay, it's there,
• 50:57
  Speaker 1: it's a blob, we know the shape. That's cool. Now
• 51:00
  Speaker 1: we're seeing sort of like how it's moving with the
• 51:02
  Speaker 1: energy flow is inside of it, which really helps us
• 51:04
  Speaker 1: build a picture for how the matter is flowing in
• 51:07
  Speaker 1: and how it's getting ejected. Yeah, pretty cool. And I
• 51:10
  Speaker 1: guess what's interesting is that we are getting these sort
• 51:12
  Speaker 1: of you know, more accurate, more interesting pictures about what's
• 51:15
  Speaker 1: going on outside of a black hole, Like we're getting
• 51:18
  Speaker 1: closer and closer to the actual black hole itself and
• 51:20
  Speaker 1: kind of maybe looking at what's going on in it. Yeah,
• 51:23
  Speaker 1: we'll be pushing up harder and harder against that envelope
• 51:26
  Speaker 1: of the event horizon. The more information we can gather
• 51:28
  Speaker 1: about what happens very close to the black hole, the
• 51:31
  Speaker 1: more it helps us refine our models for what's going
• 51:33
  Speaker 1: on inside the black hole. People talk a lot about
• 51:36
  Speaker 1: science being testable and falsifiable, right, but even if we
• 51:39
  Speaker 1: can't ever see what's inside a black hole, we might
• 51:42
  Speaker 1: be able to develop a pretty strong theory for what's
• 51:44
  Speaker 1: going on based on its impacts on the outside. If
• 51:48
  Speaker 1: we can build a theory which very accurately predicts what's
• 51:51
  Speaker 1: going on outside black holes, or predicts what happens in
• 51:54
  Speaker 1: areas we haven't seen yet, we could still test it
• 51:57
  Speaker 1: outside the black hole. And draw conclusions about what might
• 52:00
  Speaker 1: be going on inside. Wow, pretty cool. And what's amazing
• 52:03
  Speaker 1: is that we can do that from all the way
• 52:05
  Speaker 1: out here, right, Like we are along distance away from
• 52:08
  Speaker 1: this black hole. It's not like you can see it
• 52:10
  Speaker 1: in the night sky. It's like it's hidden inside of
• 52:12
  Speaker 1: a whole galaxy even right exactly, And each galaxy itself
• 52:16
  Speaker 1: is quite faint, right, this one is really really far away.
• 52:18
  Speaker 1: It's much further away than Andromeda. So it's in the
• 52:20
  Speaker 1: nice guy. It's just like a fuzzy little dot. But
• 52:23
  Speaker 1: these radio telescopes are very powerful, and so using a
• 52:27
  Speaker 1: huge telescope sort of like get pictures with slightly different angles,
• 52:31
  Speaker 1: and then we can figure out something about the dynamics
• 52:33
  Speaker 1: of what's going on the heart of that galaxy. And
• 52:36
  Speaker 1: we can study that galaxy better than we can study
• 52:38
  Speaker 1: the center of our own galaxy, right because I guess
• 52:41
  Speaker 1: there there aren't that many stars kind of block into view.
• 52:45
  Speaker 1: Is that where is that? What's going on? Two things
• 52:47
  Speaker 1: are happening there. One is that the galaxy is sort
• 52:49
  Speaker 1: of oriented in such a way that we can see
• 52:51
  Speaker 1: it's heart, whereas in the milky Way, we're like right
• 52:53
  Speaker 1: in the middle of it, and there's a lot of
• 52:55
  Speaker 1: gas and dust between us and the center of our
• 52:57
  Speaker 1: galaxy and other stars. As you say, the other thing
• 52:59
  Speaker 1: is that this thing is a monster compared to our
• 53:02
  Speaker 1: black hole, so it's much bigger and it's glowing very
• 53:05
  Speaker 1: very brightly, whereas our black hole in the center of
• 53:07
  Speaker 1: the Milky Way. Sagittarius a star is not as big.
• 53:11
  Speaker 1: I mean, it's quite impressive, but if we don't think
• 53:13
  Speaker 1: it's a quaisar, and they might or might not have
• 53:16
  Speaker 1: sort of faint astrophysical jets for us to study, but
• 53:19
  Speaker 1: we'll know soon. Because the same group is hoping to
• 53:21
  Speaker 1: point their ritual event horizon telescope at the center of
• 53:24
  Speaker 1: our galaxy and try to take a picture of Sagittarius
• 53:27
  Speaker 1: a Star. Well, they've been pointing at it all this time,
• 53:29
  Speaker 1: and it's it's just that the images from this larger
• 53:32
  Speaker 1: black hole were sort of easier or radio sooner, right, Yeah, Well,
• 53:36
  Speaker 1: they need dedicated time on these radio telescopes, which are
• 53:38
  Speaker 1: of course, you know, of interest for lots of other
• 53:40
  Speaker 1: things like searching for intelligent life and looking for exoplanets
• 53:43
  Speaker 1: and whatever. So you need dedicated, coordinated time on all
• 53:46
  Speaker 1: of these telescopes. In order to gather this data. So
• 53:49
  Speaker 1: if you've ever wonder what a black hole looks like
• 53:51
  Speaker 1: or want to see what it looks like just looking
• 53:52
  Speaker 1: up on the internet black hole photo. Although we think
• 53:55
  Speaker 1: it's a black hole, right, we talked last time about
• 53:57
  Speaker 1: how it could just be maybe a really a dark
• 54:00
  Speaker 1: star or a neutron star. Right, Yeah, we don't actually know.
• 54:03
  Speaker 1: All of this information is indirect. Most of the evidence
• 54:06
  Speaker 1: is it's something, it's very massive, it's very small, and
• 54:10
  Speaker 1: black hole is the only thing we think that fit
• 54:12
  Speaker 1: the bill. Though there are some folks out there coming
• 54:15
  Speaker 1: up with other crazy ideas, like dark stars which are
• 54:18
  Speaker 1: powered by quantum mechanics and not actually having event horizon.
• 54:22
  Speaker 1: So maybe one day we'll just have to get closer
• 54:24
  Speaker 1: so we can see one of these things with our
• 54:25
  Speaker 1: own eyes. Yeah, it could be like a gray hole.
• 54:28
  Speaker 1: We talked about that last time. Yeah, So another awesome
• 54:31
  Speaker 1: reminder of how mysterious the universe is, but also how
• 54:34
  Speaker 1: discoverable it is if we can eventually get pictures of
• 54:37
  Speaker 1: it and maybe even figure out what's going on inside
• 54:40
  Speaker 1: of the texture of the black hole itself, and how
• 54:43
  Speaker 1: physics and math can really guide is to an understanding
• 54:46
  Speaker 1: of the craziest corners of the universe, so that even
• 54:50
  Speaker 1: things like black holes and astrophysical jets can start to
• 54:53
  Speaker 1: make sense to you and to me. Physics and math,
• 54:56
  Speaker 1: how would you combine those two words? And fast fath
• 54:59
  Speaker 1: fast math mimsis mrs me, that's the one. I'm a methodist, yours?
• 55:06
  Speaker 1: Are you a mystic? Is that what you're saying. I'm
• 55:08
  Speaker 1: a mythical feature, I'm a mythical figure, you're mathematical mystical
• 55:12
  Speaker 1: most on his cosmic quest for understanding the contextual clues
• 55:16
  Speaker 1: of the cosmos. Yeah. Well, we hope they gave you
• 55:19
  Speaker 1: a lot to think about and we hope you enjoyed that.
• 55:21
  Speaker 1: Thanks for joining us, See you next time. Thanks for listening,
• 55:32
  Speaker 1: and remember that Daniel and Jorge explained the universe is
• 55:35
  Speaker 1: a production of I Heart Radio. For more podcast for
• 55:38
  Speaker 1: my heart Radio, visit the I heart Radio app, Apple Podcasts,
• 55:42
  Speaker 1: or wherever you listen to your favorite shows. Ye