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Why does our Universe have a Cold Spot? · Daniel and Kelly’s Extraordinary Universe

0:08
Speaker 1: Hey, Jorgey, does your family cook many things in the
0:11
Speaker 1: microwave oven? We used it to reheat stuff, but we
0:14
Speaker 1: don't do a lot of cooking in there, so you're
0:16
Speaker 1: not a big fan of the microwave. You're not making
0:18
Speaker 1: Thanksgiving turkeys in there, We'll only you like turkey hot
0:21
Speaker 1: spots and cold spots. Well, what if the hot spots
0:25
Speaker 1: and cold spots were actually the best part? What it's
0:29
Speaker 1: definitely the worst parts of cooking in the microwave. What
0:31
Speaker 1: if I told you that sometimes the hot spots and
0:34
Speaker 1: cold spots can hold secrets of the universe. I think
0:37
Speaker 1: I'd still read to live in a evenly heated universe.
0:56
Speaker 1: Hi am more Hammad, cartoonists and the creator of PhD comics. Hi,
0:59
Speaker 1: I'm Daniel. I'm a particle physicist, and I actually have
1:02
Speaker 1: a fancy microwave oven that doesn't generate hotspots and cold spots.
1:07
Speaker 1: That's right, you have an AI powered microwave, right, I do.
1:11
Speaker 1: It was given to me by one of our awesome
1:13
Speaker 1: listeners who heard our episode about how microwave ovens worked,
1:16
Speaker 1: and he actually developed a fancy new kind of microwave
1:20
Speaker 1: that has a thermal camera that watches your food and
1:22
Speaker 1: decides where to target the radiation. It's pretty awesome. Wow,
1:26
Speaker 1: has it taken over your life now? Isn't you know?
1:29
Speaker 1: Your new microwave overlord. The kids are worried that it's
1:32
Speaker 1: going to tell them what to eat and win. Just
1:35
Speaker 1: don't connect. Get to the internet, Daniel, it's probably listening
1:39
Speaker 1: to podcast right now. Say something nice about it. It's
1:42
Speaker 1: gonna scall to you in your next meal. But welcome
1:45
Speaker 1: to our podcast. Daniel and Jorge explained the Universe State
1:48
Speaker 1: production of Our Heart Radio, in which we think about
1:50
Speaker 1: everything out there in the universe, the mysterious thoughts of
1:53
Speaker 1: microwave ovens, to the interiors of black holes, to the craziest,
1:58
Speaker 1: tiniest things happening in the microscopic level. We think about
2:01
Speaker 1: the huge things in the universe and try to understand
2:04
Speaker 1: the grand scale of the cosmos, and we think about
2:07
Speaker 1: the tiniest little particles that make up me and you
2:10
Speaker 1: and hamsters and microwave dinners. Yeah, because physics is all
2:15
Speaker 1: around us. It's in our fingertips, it's in the food
2:17
Speaker 1: we eat and how we heat it up, and it's
2:20
Speaker 1: also out there on the vast reaches of space. It's
2:23
Speaker 1: physics is everywhere, Physics is everywhere, and it's doing a
2:26
Speaker 1: pretty good job at revealing to us the nature of reality,
2:30
Speaker 1: letting us like pull back a layer and see what's
2:32
Speaker 1: really going on. Sometimes the answer is staring you in
2:35
Speaker 1: the face, like learning that the Earth goes around the
2:38
Speaker 1: Sun rather than the other way around. But sometimes it
2:41
Speaker 1: takes some real sleuthing to pull the clues out of
2:44
Speaker 1: the cosmos. Yeah, because the universe sort of screaming at
2:47
Speaker 1: us all the time, right with data and information. It's
2:50
Speaker 1: sort of revealing itself to us all around us all
2:53
Speaker 1: the time. But it's sort of recognizing what's happening. That's
2:56
Speaker 1: the hard part. Yes, sometimes it's obvious, and sometimes you
2:59
Speaker 1: have to look for those subtle little clues because it
3:02
Speaker 1: doesn't seem like the universe was designed to be easy
3:06
Speaker 1: to figure out. After all, has taken us some thousands
3:08
Speaker 1: of years, and sometimes we learned that there is evidence
3:11
Speaker 1: all around us that we didn't even know existed that
3:14
Speaker 1: tells us a crazy story about the origins of the universe. Daniel,
3:19
Speaker 1: do you feel like physicists are sometimes like reality detectives
3:22
Speaker 1: that you're trying to reconstruct what happened in the universe
3:25
Speaker 1: and what's going on and who's guilty? Yeah, exactly. Sometimes
3:29
Speaker 1: in our best moments, I feel like we're Sherlock Holmes,
3:32
Speaker 1: you know how he's famous for like figuring out exactly
3:34
Speaker 1: what happened based on the kind of ash sprinkled on
3:37
Speaker 1: somebody's shoe, you know, or a particular form of dirt,
3:41
Speaker 1: or a kind of thread used by only one factory
3:44
Speaker 1: in northern England or something. It's cases like that when
3:46
Speaker 1: we have to figure out what happened in the universe
3:48
Speaker 1: based on really subtle little clues that I feel like
3:52
Speaker 1: physics is really doing its job. Do you keep like
3:55
Speaker 1: a magnifying glass at your desk just in case a
3:57
Speaker 1: clue revealed itself right next to you. I don't know.
4:00
Speaker 1: If the universe is a murder mystery. Who's getting murdered.
4:03
Speaker 1: Probably us? Well, technically we all get murdered by the universe.
4:08
Speaker 1: Eventually mystery solved. There you go. We know what the
4:10
Speaker 1: culprit is. It was the universe, with the universe in
4:13
Speaker 1: the universe, with the entropy in the gamma, decay of
4:17
Speaker 1: our courts. That's right exactly. But it's fun, right, It's
4:21
Speaker 1: a fun mystery. Sometimes you learn something boring. You go
4:24
Speaker 1: out there and you study, and you learn exactly what
4:26
Speaker 1: you expected. But sometimes you go out there and you
4:28
Speaker 1: find something exciting, something interesting, something surprising, something puzzling that
4:32
Speaker 1: tells you there's still more to learn about this incredible cosmos. Yeah,
4:36
Speaker 1: and you know, one of the biggest mysteries that you
4:39
Speaker 1: I feel like you physicists are trying to figure out
4:41
Speaker 1: is basically the whole universe, like where it came from,
4:44
Speaker 1: how did it come to be, what's it made out of?
4:47
Speaker 1: Why is it the way it is right now? Yeah, precisely,
4:49
Speaker 1: we want to know, like how does it look? Is
4:51
Speaker 1: it look the same way here as it does somewhere else,
4:53
Speaker 1: How far does it go on? And where did it
4:55
Speaker 1: all come from? It's basically the biggest mystery in human history.
4:59
Speaker 1: You know, I'd put it up there is one of
5:01
Speaker 1: the biggest questions in science and one of the biggest
5:04
Speaker 1: questions in like, you know, human existence. Where did this
5:07
Speaker 1: all come from? And amazingly, we actually like have some answers,
5:11
Speaker 1: We have beginnings of ideas for how to unravel this
5:14
Speaker 1: because we've detected clues from the very early universe. Yeah,
5:18
Speaker 1: and so one thing that's interesting about the universe. Is
5:21
Speaker 1: that there's a picture of it. I mean not just
5:23
Speaker 1: all around us we can see the universe, but we
5:25
Speaker 1: have a picture of it from the early beginnings of
5:27
Speaker 1: the universe, like a baby picture of the universe. Yeah,
5:30
Speaker 1: it's incredible. If you sniff around through all the light
5:33
Speaker 1: that's flying around, through all the photons that are banging
5:35
Speaker 1: into each other, you can find a certain set of
5:38
Speaker 1: photons that were generated when the universe was very very young.
5:42
Speaker 1: Put that together, and you're absolutely right. You get a
5:44
Speaker 1: picture of the early universe. And that picture is so
5:48
Speaker 1: rich in information that tells us about how the universe
5:51
Speaker 1: was formed, what it looked like, how much dark energy
5:54
Speaker 1: there is, how much dark matter there is. It's really
5:56
Speaker 1: a treasure trove of information about how our universe came
5:59
Speaker 1: to be and what's going to happen to it. Yeah,
6:02
Speaker 1: and apparently something that sticks out about that picture of
6:04
Speaker 1: the universe is that it's not perfectly even. It has
6:08
Speaker 1: hot spots and cold spots. Yeah, it has wiggles, just
6:12
Speaker 1: like our universe has hot spots and cold spots. Right
6:15
Speaker 1: Like the Sun, for example, is hotter than a lot
6:18
Speaker 1: of empty space. Just like that, we can backtrack to
6:21
Speaker 1: the early universe, and we see that there are wiggles.
6:23
Speaker 1: They're also there are little hot spots and little cold spots,
6:27
Speaker 1: but they're much more subtle in the very early universe
6:29
Speaker 1: that we've done a lot of detailed analyzes of these
6:32
Speaker 1: hot spots and cold spots to see like what do
6:33
Speaker 1: they mean about the distribution of matter and how did
6:36
Speaker 1: that lead to the big structures that we see today?
6:40
Speaker 1: And so to be on the podcast, we'll be tackling
6:42
Speaker 1: the question does the universe have a cold spot or
6:51
Speaker 1: a cold sword? Daniel? And can we put windeck kind it?
6:55
Speaker 1: Do you want to take care of the universe since
6:57
Speaker 1: you already figured out it's going to murder you. Well,
7:00
Speaker 1: it also gave birth to me, so you know it's
7:03
Speaker 1: a complicated relationship. So it's a zero moral balance overall. Well,
7:08
Speaker 1: it's positive for me for now. I don't know if
7:12
Speaker 1: the universe sees me as a net positive, but I
7:14
Speaker 1: definitely see myself as a net positive for me. I
7:17
Speaker 1: think you're definitely a net positive for the universe or head, Oh,
7:20
Speaker 1: thank you at least for this podcast. You're definitely a
7:23
Speaker 1: hot spot for the universe. Yes, I definitely have a
7:26
Speaker 1: spot for the universe in my heart. But this cosmic
7:30
Speaker 1: microwave background radiation, this light we study from the very
7:34
Speaker 1: early universe does have hot spots and cold spots, and
7:37
Speaker 1: in particular there's one spot that's extra big and extra cold. Yeah,
7:42
Speaker 1: it's a big mystery in physics. And so we were wondering,
7:45
Speaker 1: as usual, if people out there knew that the universe
7:49
Speaker 1: had a cold spot, like a big glaring cold spot,
7:52
Speaker 1: And so Daniel went out there and asked people on
7:54
Speaker 1: the internet if they knew if the universe has a
7:56
Speaker 1: cold spot. So thanks to everybody who participated. If you
8:00
Speaker 1: would like to basils the speculate on difficult topics in physics,
8:04
Speaker 1: please write to me two questions at Daniel and Jorge
8:07
Speaker 1: dot com. So think about it for a second. Have
8:09
Speaker 1: you heard of the universe having a cold spot? And
8:11
Speaker 1: what would you answer? Here's what people had to say.
8:14
Speaker 1: Sounds like a medical thing. What does the CNB? I
8:17
Speaker 1: think it probably means central massive blackhole, maybe the black
8:24
Speaker 1: hole the center of the galaxy. That's just a guess,
8:27
Speaker 1: or it's super massive, but this the c is in
8:30
Speaker 1: place of the that wouldn't be too off from health.
8:33
Speaker 1: Physicists like do their acronyms. I think it's a trick question.
8:37
Speaker 1: They don't think it has a call, but I think
8:38
Speaker 1: it's all called. I actually was reading about that a
8:42
Speaker 1: little while ago. So the CNB being cosmic microwave background radiation,
8:47
Speaker 1: that map that was drawn up showed a dark spot
8:51
Speaker 1: in it that would potentially denote a void of some kind,
8:56
Speaker 1: being just a massive space where galaxies are all surrounding it,
9:00
Speaker 1: but there's nothing in it, a big void. So that's
9:03
Speaker 1: what I think it would be. But the other alternative
9:06
Speaker 1: theory to it was that it could potentially be a
9:09
Speaker 1: signal of another universe, so that would be where a
9:13
Speaker 1: parallel universe would exist. But the science behind that is
9:16
Speaker 1: completely lost on me, and it goes straight over my
9:19
Speaker 1: head thinking of expansion and thinking of this video I
9:24
Speaker 1: saw of um legos getting smashed by a hammer from
9:29
Speaker 1: high up. There's one spot where the legos clumped together
9:32
Speaker 1: and that was close to the point of impact. And
9:36
Speaker 1: I you know, back to quantum fluctuations. Dark matters a
9:41
Speaker 1: big part of the creation universe. It's fingerprints are there um.
9:46
Speaker 1: So this is a part that was close to the
9:48
Speaker 1: impact that cooled down first. Well, this cold spots might
9:53
Speaker 1: be caused by like being really far away from where
9:56
Speaker 1: the Bagman happened, so it has had a lot of
9:59
Speaker 1: time to cool that. I remember hearing about it in
10:02
Speaker 1: the movies. A lot I don't remember, but I think
10:04
Speaker 1: it's something to do with like either time travel or
10:09
Speaker 1: bending space. All right, Well, first of all, I see
10:14
Speaker 1: you made the error of asking people with an acronym.
10:17
Speaker 1: He asked him why does the CMB have a could spot?
10:19
Speaker 1: And most people were like, what, what does the CMB
10:22
Speaker 1: central massive black hole cool mega bears? Sometimes it's hard
10:28
Speaker 1: for me to get out of my physics head and
10:29
Speaker 1: forget that CMB, you know, might have any other meaning.
10:32
Speaker 1: It's one of these acronyms we use in physics all
10:34
Speaker 1: the time, so I forgot that it might not be
10:37
Speaker 1: something people are familiar with. So yeah, we got some
10:39
Speaker 1: fun interpretations. Shockingly, not everyone knows what CMB means, although
10:44
Speaker 1: I don't know if you're watching one division they referenced
10:46
Speaker 1: the CMB. They do reference the CMB, but they call
10:49
Speaker 1: it the c m b R. It's like, no afterphysicists
10:53
Speaker 1: would call it the c m b R because that
10:55
Speaker 1: would be the accurate exactly, And we know how these
10:58
Speaker 1: names work right. You call it cosmic microwave background radiation,
11:02
Speaker 1: but the acronym is CMB right because it makes because
11:06
Speaker 1: it makes no sense, and therefore it's a name for
11:08
Speaker 1: astrophysics exactly. See, you're just trying to exclude more people
11:11
Speaker 1: from knowing what you're talking about. It just shows that
11:14
Speaker 1: they didn't really consult an astrophysicist when they wrote that episode,
11:18
Speaker 1: or they did and they ignored it to correct you. Yeah,
11:22
Speaker 1: they're like, that doesn't make any sense. Come on, this
11:24
Speaker 1: is a Marvel movie television show. We need to make sense.
11:28
Speaker 1: That's a new standard for Marvel apparently. Yeah, well you
11:31
Speaker 1: know that they figured that out in The Quantum Realm.
11:35
Speaker 1: I just did a whole episode on the physics of
11:38
Speaker 1: ant Man with a fun new podcast. It's a podcast
11:41
Speaker 1: called The Marvels of Science with Dave Reinersman. So check
11:46
Speaker 1: it out fans of Marvel and science. I actually gave
11:49
Speaker 1: it pretty positive reviews. You know, the physics oftment the
11:51
Speaker 1: quantum physics is pretty well done. Nice. But anyways, the
11:55
Speaker 1: cosmic microwave background radiation has apparently a cult spot and
11:59
Speaker 1: it tells us something about the universe, So I guess
12:01
Speaker 1: maybe step us through Daniel. First of all, for those
12:04
Speaker 1: of us who don't know what the CNB is, what
12:06
Speaker 1: is the cosmic microwave background radiation? With an R Oh,
12:10
Speaker 1: you mean the CMB r Oh, Yeah, that's something totally different. No,
12:13
Speaker 1: the CNB, the cosmic microwave background. These are just photons
12:17
Speaker 1: right there, light like anything else, but they're light of
12:20
Speaker 1: a different frequency. And these photons are particularly interesting because
12:24
Speaker 1: they're super duper old, so they're like a picture of
12:28
Speaker 1: the very early universe. We don't know exactly what happened
12:31
Speaker 1: in the very beginning of the universe, but we suspected that,
12:34
Speaker 1: like a few hundred thousand years after the universe was born,
12:37
Speaker 1: it was still really hot. It was a nasty, wet plasma,
12:41
Speaker 1: super duper burning. It hot and life most plasmas, it
12:44
Speaker 1: was opaque, like the sun is a plasma, right, it's
12:47
Speaker 1: a glowing ball of gas and you can't see through it,
12:50
Speaker 1: and the light that's generated inside of it gets reabsorbed
12:53
Speaker 1: by the stuff in it. But at some point, because
12:56
Speaker 1: the universe was cooling and expanding, that is, mc cooled
13:00
Speaker 1: to the point where it couldn't absorb its own light anymore.
13:03
Speaker 1: It is sometimes called the surface of last scattering, There
13:06
Speaker 1: was this moment when it was giving off light and
13:09
Speaker 1: then all of a sudden it couldn't absorb it. So
13:11
Speaker 1: that light that was generated by the plasma just before
13:14
Speaker 1: it cooled is still flying around. That's the cosmic microwave background. Yeah,
13:19
Speaker 1: it's like that moment when the universe sort of crystallized
13:22
Speaker 1: and weighing and it became transparent. That light is still
13:25
Speaker 1: flying around, but is it's still like bouncing around or
13:28
Speaker 1: or like is the cosmic microwave radiation that we get
13:31
Speaker 1: like the actual original photons that were started flying at
13:35
Speaker 1: the Big Bang, they are the original photons, but it
13:38
Speaker 1: does bounce around like it gets absorbed, it interacts with stuff,
13:41
Speaker 1: So not every single photon that was generated back then
13:45
Speaker 1: is still around. They can't interact with other things and
13:47
Speaker 1: get absorbed, but there's plenty of them left over for
13:50
Speaker 1: us to see. But when we see one, we typically
13:52
Speaker 1: see it before it's interacted with anything else, And so
13:56
Speaker 1: will exactly happened that made the universe transparent, like everything
14:00
Speaker 1: became crystallized or glass or what does that mean? Well,
14:04
Speaker 1: the key thing to understand is that the universe was cooling,
14:06
Speaker 1: so you have a hot plasma, which is basically like atoms,
14:09
Speaker 1: but the electrons and the nuclei are separated so much
14:13
Speaker 1: energy that the electrons can't be trapped by the nuclei.
14:16
Speaker 1: But then as it cools, the electrons slow down and
14:20
Speaker 1: they get captured by the nuclei. And so this goes
14:22
Speaker 1: from ionic it's like charge, and it's absorbing and emitting
14:26
Speaker 1: a lot of radiation to neutral and all of a sudden,
14:29
Speaker 1: those photons can just fly through a sea of neutral
14:31
Speaker 1: atoms without getting absorbed or interacted with. Before it was
14:35
Speaker 1: like a soup and it would get pulled in all
14:37
Speaker 1: kinds of directions. But now everyone is just more chill,
14:40
Speaker 1: and so photons can just fly through, yeah, exactly, and
14:43
Speaker 1: neutral atoms they can absorb photons and they can give
14:45
Speaker 1: off photons, but only a certain wavelengths because of the
14:48
Speaker 1: electron energy levels. You know, free electrons can absorb and
14:52
Speaker 1: emit photons of any wavelength. That's why like plasma glows
14:55
Speaker 1: and many more frequencies than like hydrogen gas. For example,
14:58
Speaker 1: So when the universe cooled from a plasma to just
15:01
Speaker 1: like clouds of hydrogen gas, that gas was mostly transparent
15:05
Speaker 1: to the light that had just been created and another
15:07
Speaker 1: thing for people to keep in their minds. When you
15:09
Speaker 1: think about the CMB plasma, you might be imagining like
15:12
Speaker 1: a blob of gas that's burning and giving off light
15:15
Speaker 1: like our sun. And then you think, well, that light
15:17
Speaker 1: is now, you know, flying fourteen billion years away, must
15:20
Speaker 1: be in a big sphere. How are we seeing it now?
15:23
Speaker 1: How is it just like coming to us now. The
15:25
Speaker 1: way to think about it, though, is that it was
15:27
Speaker 1: everywhere and this plasma field the whole universe so simultaneously
15:31
Speaker 1: making photons in every direction. The ones that we are
15:34
Speaker 1: seeing now came from plasma that was really really far
15:37
Speaker 1: away a long time ago, and it's just reaching us.
15:40
Speaker 1: But the photons we see in one direction are not
15:43
Speaker 1: from the same bit of plasma as the photons we
15:45
Speaker 1: see in another direction. Those are two totally separate bits
15:49
Speaker 1: of plasma whose photons are both reaching Earth right now,
15:52
Speaker 1: right because this microrave radiation is coming at us from
15:56
Speaker 1: all around us, right Like if you point like your
15:58
Speaker 1: small radio at the sky, you'll sort of pick up
16:01
Speaker 1: this this noise right. That's right, every direction of the
16:03
Speaker 1: sky you see this radiation because it's coming from everywhere
16:08
Speaker 1: in the universe and everywhere you look, you see it
16:10
Speaker 1: from a different location. Just like if you look in
16:12
Speaker 1: one direction you see a star, you're seeing light from
16:15
Speaker 1: the star really far away. You look in another direction
16:18
Speaker 1: and you're looking at a star. You're seeing light from
16:20
Speaker 1: the star really far away in the other direction. Both
16:23
Speaker 1: of those have had photons flying through space for billions
16:27
Speaker 1: of years just arriving at Earth. So you're looking at
16:30
Speaker 1: very different parts of the universe when you look out
16:32
Speaker 1: at different parts of the sky. And that's also true
16:35
Speaker 1: for the cosmic microwave background radiation, Like if you look left,
16:39
Speaker 1: you'll be looking at a different part of the early universe,
16:42
Speaker 1: and if you look right. But I guess the question
16:44
Speaker 1: is if I look in one particular direction and I
16:46
Speaker 1: keep looking there, am I getting the photons from the
16:49
Speaker 1: same spot of the universe or is it kind of
16:52
Speaker 1: like an observable universe thing where you know, I'm looking
16:55
Speaker 1: at photons from the early universe further and further out
16:58
Speaker 1: the longer I look. Yeah, you're looking for further and
17:00
Speaker 1: further out the longer you look. So the CMB that
17:03
Speaker 1: we see will change as time goes on, because we're
17:06
Speaker 1: essentially looking at it from a larger and larger sphere
17:09
Speaker 1: I see. So we're sort of getting a three D
17:11
Speaker 1: picture almost the universe, yes, exactly, because it's not a
17:14
Speaker 1: continuous source in time the way a star is. Right,
17:17
Speaker 1: when you look at a star, you're seeing the star
17:19
Speaker 1: where it is, and it's continuing to beam photons at
17:22
Speaker 1: you every second, and so as you look at it,
17:24
Speaker 1: you see new photons. But the CMB was generated in
17:27
Speaker 1: one moment. It's one moment in time, and so when
17:30
Speaker 1: you look out at the same b right now, you're
17:33
Speaker 1: seeing like a shell around the Earth, and then ten
17:35
Speaker 1: seconds later you see the c MB from a larger shell,
17:38
Speaker 1: ten light seconds larger than the previous one. And it's
17:42
Speaker 1: a wiggling in time, like is it sort of changing
17:45
Speaker 1: in volume as well as in direction. There are some wiggles.
17:48
Speaker 1: I mean, it's pretty faint and we've only been observing
17:51
Speaker 1: it for a few years, so we don't expect to
17:53
Speaker 1: see like variations on that kind of time scale. Al right,
17:57
Speaker 1: So that microwave radiation tells is it's like a picture
18:01
Speaker 1: of that early universe when it sort of crystallized and
18:03
Speaker 1: cool down, and the mysteries that are hot and cold
18:07
Speaker 1: spots on it, right, Like if you look at the
18:08
Speaker 1: temperature of that radiation, it's not even so here physicists
18:11
Speaker 1: are sort of playing a little game. They're saying, those
18:14
Speaker 1: photons themselves don't have a temperature. We're talking about the
18:18
Speaker 1: heat of the thing that made the photons. And there's
18:21
Speaker 1: this concept in physics, this connection between the frequency of
18:24
Speaker 1: light you generate and the temperature you have. And it's
18:27
Speaker 1: pretty simple when you think about it. Hot things tend
18:29
Speaker 1: to glow, and as they get hotter, they glow in
18:32
Speaker 1: higher frequencies, like everything around you is actually glowing in
18:36
Speaker 1: very low frequencies. You're giving off infrared radiation right now.
18:40
Speaker 1: If you heat it up your body really really hot,
18:42
Speaker 1: not recommended the thousands of degrees, you would glow red,
18:45
Speaker 1: or you would glow blue, or you would glow white.
18:47
Speaker 1: That's why the Sun, for example, glows more than the
18:50
Speaker 1: Earth because it's much much hotter. So when we talk
18:52
Speaker 1: about the temperature of the CMB, we really mean the
18:55
Speaker 1: temperature of a thing that would give off light at
18:58
Speaker 1: that frequency. So when you tell your spouse that they
19:01
Speaker 1: have a special glow about them, really you're just saying
19:04
Speaker 1: that they glow like everything else exactly. But if they're
19:08
Speaker 1: extra hot, then maybe they are radioactive, or maybe they're
19:13
Speaker 1: just glowing red and angry at you or something. And
19:17
Speaker 1: so when we look at like the temperature of the
19:19
Speaker 1: CNB really means the wavelength of the CNB, and if
19:22
Speaker 1: something is hotter, then it's a little bit more blue shifted.
19:25
Speaker 1: If something is colder, it's a little bit more red shifted. Right,
19:28
Speaker 1: But it tells you, basically, at the end of the day,
19:30
Speaker 1: how hot or how cold that early universe was in
19:34
Speaker 1: different directions. Yeah, it does. It can't tell you that now.
19:37
Speaker 1: The temperature that we measure is sort of a crazy,
19:39
Speaker 1: crazy low temperature. It's like two point seven degrees kelvin,
19:43
Speaker 1: which is like just above absolute zero. Right, it's really
19:46
Speaker 1: really cold. And that seems confusing because we're saying that
19:49
Speaker 1: the universe was really really hot, right it was like
19:52
Speaker 1: a hot burning plasma. Well it was. It was like
19:55
Speaker 1: three thousand degrees kelvin when this light was made. But
19:58
Speaker 1: the light has gotten red shift over time because the
20:01
Speaker 1: universe is expanding and that stretches out that light lengthens
20:05
Speaker 1: its wavelength and lowers its effective temperature. Right, all right, Well,
20:08
Speaker 1: so then we're noticing that it has cold spots and
20:11
Speaker 1: temperature that radiation, and so there are hot and cold spots.
20:16
Speaker 1: So let's talk about what that big cold spot is
20:18
Speaker 1: and what it could mean. But first let's take a
20:21
Speaker 1: quick break, all right, Daniel. We're trying to cure the
20:35
Speaker 1: universe of its cold sore. The universe is going on
20:40
Speaker 1: a date and it wants to look hot. Yeah, or
20:43
Speaker 1: to figure out if we live in a hot spot.
20:45
Speaker 1: It's pretty happening around here and on Earth. But who knows,
20:48
Speaker 1: Maybe we're we're in the cold spot, or maybe our
20:50
Speaker 1: whole universe is not that hot out there in the multiverse.
20:53
Speaker 1: Maybe there are much hotter universes. Oh man, See now
20:56
Speaker 1: you're just playing that game. You're saying that the light
20:58
Speaker 1: is greener on the other side of the multiverse. I'm
21:00
Speaker 1: just saying, you know, maybe our universe should get on
21:02
Speaker 1: universe tinder and consider its options. It might choose a
21:06
Speaker 1: different you here hoping for or worried about. No, I'm
21:10
Speaker 1: just saying, you know, hey, get some quantum entanglement going on,
21:13
Speaker 1: we can get some information from another universe. Boy, Now
21:15
Speaker 1: you sound like a Marvel movie. Dan. All right, so
21:19
Speaker 1: there's a cosmic microwave background radiation it's coming at us
21:22
Speaker 1: from all directions, and it's telling us about the early universe,
21:26
Speaker 1: and there are cold spots in it. So tell me
21:28
Speaker 1: about these cold spots. And apparently there's one big cold spot. Yeah.
21:32
Speaker 1: So when they first found this radiation, it was really
21:34
Speaker 1: exciting because it was essentially proof that the universe had
21:37
Speaker 1: once been plasma. That was really cool. And they looked
21:40
Speaker 1: at it and it was pretty smooth at first, like
21:42
Speaker 1: it's basically the same temperature everywhere. But then they made
21:45
Speaker 1: better and better measurements of it and they found these wiggles.
21:48
Speaker 1: They found these hot spots and these cold spots, and
21:51
Speaker 1: these are actually really really small wiggles, like we're talking
21:55
Speaker 1: about twenty microkelvin's or so, like one factor in a
21:59
Speaker 1: hundred thousand. So it's almost exactly smooth, but there are
22:03
Speaker 1: these little variations in temperature, kind of like a texture
22:07
Speaker 1: almost to the light. Yeah, kind of like a texture.
22:10
Speaker 1: And you might think, oh, well, that's just nothing, but
22:12
Speaker 1: there are statistically significant, like we've measured enough of these
22:15
Speaker 1: photons to tell that it's a real effect. It's not
22:17
Speaker 1: just like noise in the data. It's fascinating because those
22:20
Speaker 1: little wiggles tell us about wiggles in the early universe,
22:23
Speaker 1: which revel really interesting and important facts about the nature
22:27
Speaker 1: of the universe itself. And they're pretty consistent, I imagine, right,
22:30
Speaker 1: Like if you take a picture of the microwave cosmic
22:33
Speaker 1: background now and I take another picture of it later,
22:36
Speaker 1: you'll see the same wiggles, Like the wiggles won't go away. Yeah, exactly.
22:39
Speaker 1: These come from wiggles in the original plasma, and so
22:42
Speaker 1: we're seeing those exactly, they're still there. Yeah. Like if
22:45
Speaker 1: you point your antenna at one spot in the sky,
22:48
Speaker 1: you'll get consistently a little cooler measurement there, right, or
22:52
Speaker 1: a hotter exactly. And you need a really really refined
22:55
Speaker 1: measurement in order to even see this, because it's like
22:57
Speaker 1: one part in a hundred thousand. You need a very
22:59
Speaker 1: very find instrument to capture that, right. And So what
23:03
Speaker 1: causes these variations in the temperature of the universe, Like
23:06
Speaker 1: why is it colder or hotter in some places than others? Yeah,
23:09
Speaker 1: it's fascinating. There are two main reasons. One is that
23:14
Speaker 1: there just were hot spots and cold spots like in
23:16
Speaker 1: the original plasma. Quantum fluctuations. You know, you might imagine
23:21
Speaker 1: the universe starting sort of like smoothly, like homogeneously, like
23:24
Speaker 1: every place in the universe when he was born. However
23:27
Speaker 1: that happened was the same. So then how do you
23:29
Speaker 1: go from that to like having a star here and
23:32
Speaker 1: not having a star there. Well, that has to begin somewhere,
23:36
Speaker 1: and we think that quantum fluctuations in the very very
23:39
Speaker 1: early original universe, well before this plasma then got like
23:43
Speaker 1: blown up by cosmic inflation, this process where you take
23:47
Speaker 1: the universe and you expanded by like ten to the
23:50
Speaker 1: thirty intend of the minus thirty seconds. So you get
23:53
Speaker 1: these random quantum wiggles in the very early universe which
23:56
Speaker 1: then get blown up into macroscopic wiggles in a real universe,
24:01
Speaker 1: which lead to like little hot spots and little cold
24:03
Speaker 1: spots in this original plasma. Mm hmmm. That's because the
24:07
Speaker 1: early universe was so small, right, Like, it was so
24:09
Speaker 1: small and so compact, and everything was crunched together so
24:12
Speaker 1: much that the quantum uncertainty of this quirk or this
24:17
Speaker 1: particle made a big difference. It's hard to talk about
24:20
Speaker 1: the original universe as small, because I think it was
24:23
Speaker 1: always infinite, and so we had an infinite universe which
24:25
Speaker 1: then got like expanded massively to an infinite universe, and
24:30
Speaker 1: you know, it's harder to think about it as bigger
24:32
Speaker 1: or smaller. Some like subtle mathematics, they're like, are there
24:35
Speaker 1: more numbers between zero and one than they're between zero
24:38
Speaker 1: and ten? There aren't. Actually, there's no one to one
24:43
Speaker 1: mapping between those two things. So the universe is like
24:46
Speaker 1: technically the same size even though it expanded. That's a
24:49
Speaker 1: whole other mind bending discussion. But you're exactly right, little
24:52
Speaker 1: like quirk to quirk fluctuations, little quantum randomness. Right, The
24:56
Speaker 1: only way something can happen differently in one spot than
24:59
Speaker 1: in another if of the same initial conditions is through
25:02
Speaker 1: quantum mechanics. It's the only source of actual randomness. Usually
25:05
Speaker 1: we don't notice that it doesn't affect anything, But if
25:07
Speaker 1: all of a sudden, random quantum fluctuations get blown up
25:11
Speaker 1: to the macroscopic size by inflation, then it does matter
25:14
Speaker 1: that it can have a real impact on the shape
25:16
Speaker 1: of the universe. Right. It's sort of like when you
25:18
Speaker 1: zoom in on a picture on your phone or a
25:21
Speaker 1: computer screen, Like you blow it up, but you can
25:23
Speaker 1: see all the imperfections in it, right, And then we
25:25
Speaker 1: can actually do some really amazing physics. We can model
25:28
Speaker 1: that plasma. We can say, well, that plasma was probably
25:31
Speaker 1: some percentage dark matter and some percentage quirks, and some
25:34
Speaker 1: percentage light, and we understand how those things like attract
25:38
Speaker 1: each other and bounce off each other. So people have
25:40
Speaker 1: done incredibly detailed studies of like the acoustic oscillations of
25:45
Speaker 1: that plasma, understanding how those things are bouncing against each other,
25:49
Speaker 1: and measuring from that plasma how much dark matter there
25:53
Speaker 1: was in the universe, because dark matter and quarks interact
25:57
Speaker 1: very differently, so they change the shape of those oscillations
26:00
Speaker 1: in that original plasma. Right. That's one of the ways
26:03
Speaker 1: we know that dark matter exists in that it exists
26:05
Speaker 1: at a certain percentage of the universe is because it
26:08
Speaker 1: cosmic microrade background radiation tells you how much dark matter
26:11
Speaker 1: there was and is in the universe exactly. And it's
26:14
Speaker 1: those hot spots and cold spots that tell you, like,
26:16
Speaker 1: if there was more dark matter, then you would have
26:19
Speaker 1: different kinds of wiggles and oscillations in that original plasma,
26:22
Speaker 1: and then you would see a different pattern of hot
26:25
Speaker 1: spots and cold spots in the CNB today. So that's
26:28
Speaker 1: one source of the hot spots and cold spots, like
26:30
Speaker 1: the original primordial plasma itself was hotter or colder. But
26:34
Speaker 1: then there's another super fascinating, really interesting way that this
26:38
Speaker 1: light can get hotter and colder. What is it? Well,
26:40
Speaker 1: it turns out that as this light flies through the
26:42
Speaker 1: universe to us, it basically measures how much matter is
26:46
Speaker 1: along the way. If that light passes through really dense
26:49
Speaker 1: regions of the sky, it picks up some energy and
26:52
Speaker 1: it gets bluer. If the light passes through like really
26:54
Speaker 1: really empty regions of the sky, then it loses some
26:57
Speaker 1: of its energy as it leaves like the obviously more
27:00
Speaker 1: dense region, and it gets redder. So some of the
27:03
Speaker 1: red and blue shifts in the CNB, the hot and
27:06
Speaker 1: cold spots come from differences and how much stuff there
27:10
Speaker 1: is now between us and where the lights started. So
27:13
Speaker 1: sort of like measuring the density of the universe along
27:16
Speaker 1: the line right, interesting, So can you tell the difference
27:19
Speaker 1: like how much a variation in the radiation is due
27:23
Speaker 1: to its original fluctuations or it's present fluctuations. Can you
27:28
Speaker 1: tell the difference? Yeah, we can. We think that make
27:30
Speaker 1: very different sort of scale effects like these variations due
27:34
Speaker 1: to structure and density make very large scale effects that
27:38
Speaker 1: have like effects of the size of like ten degrees
27:40
Speaker 1: on the sky, whereas the other ones that indicate like
27:43
Speaker 1: you know, the very on acoustic ostillations and the fraction
27:46
Speaker 1: of dark matter make much smaller effects. And so it's
27:48
Speaker 1: fascinating because you can sort of like pull apart this information.
27:52
Speaker 1: You can learn very different things about the universe, what's
27:55
Speaker 1: going on today, the density of stuff, and what happened
27:58
Speaker 1: the very early universe by studying the hot spots and
28:00
Speaker 1: cold spots at different scales. All right, Well, for the
28:04
Speaker 1: most part, these variations in the cosmic microwave background are
28:08
Speaker 1: sort of small, right, Like, if you look at a
28:10
Speaker 1: picture of the cosmic microwave background radiation, it sort of
28:13
Speaker 1: looks like almost television noise, right for the most part, Yeah, exactly,
28:17
Speaker 1: it's pretty smooth. Like you look around the CMB and
28:20
Speaker 1: you see typically variations of about you know, twenty microkelvin's,
28:24
Speaker 1: and they tend to be like, you know, about one
28:26
Speaker 1: angular degree. Sometimes there are larger effects because like we're
28:30
Speaker 1: moving through the rest frame of this radiation, et cetera.
28:33
Speaker 1: But typically we see like you know, twenty microkelvin's about
28:36
Speaker 1: one angular degree, and that's about what you expect. You know,
28:39
Speaker 1: you expect some variation, some hot or some cold, or
28:42
Speaker 1: some a little cold or some a little hotter. But
28:44
Speaker 1: we expected to follow like a pretty nice and tidy
28:47
Speaker 1: statistical distribution. Yeah, like I was saying, it sort of
28:49
Speaker 1: looks like television noise. But if you look in some spots, though,
28:52
Speaker 1: you do see kind of bigger features in this noise, right,
28:56
Speaker 1: almost like some ghostly features in your TV static. Yeah,
28:59
Speaker 1: there's one spot has astrophysicists and cosmologists puzzling for like
29:04
Speaker 1: more than a decade, and it's called the cold spot,
29:07
Speaker 1: and it's a spot in the sky where this radiation
29:10
Speaker 1: is surprisingly cold. It's much colder than it is anywhere else,
29:14
Speaker 1: and it's a much bigger spot than you expect to see.
29:16
Speaker 1: So this thing is like seventy or up to a
29:19
Speaker 1: hundred and fifty microkelvin's colder than the average CNB temperature,
29:24
Speaker 1: and it's like five angular degrees. So you can see
29:27
Speaker 1: this thing with your eye, like, what, oh, not what
29:29
Speaker 1: you like? If you see the picture of the costming
29:33
Speaker 1: microwave background, Yeah, that's right. You can't see the CNB
29:35
Speaker 1: with your eye, right, it's in microwave frequencies, though I
29:38
Speaker 1: guess it does gently cook your food. But you can't
29:40
Speaker 1: see it with your eye. But if you look at
29:42
Speaker 1: a plot of this stuff you see this spot, you're like, oh,
29:45
Speaker 1: there's an extra dark blue spot there where you might
29:47
Speaker 1: not otherwise expect it. M M. Now is that a
29:50
Speaker 1: lot of five angular degrees? How big in the sky
29:53
Speaker 1: are we talking about? Like the size of the sun
29:55
Speaker 1: as we will see it, or the moon or of
29:58
Speaker 1: texas well, the moon is about half a degree in
30:01
Speaker 1: the sky, and so yeah, this is a pretty big
30:03
Speaker 1: effect I see. So like if you lived to look out,
30:06
Speaker 1: you would see like something ten times larger than the moon.
30:09
Speaker 1: And that's how big this could spot is, yeah, exactly.
30:12
Speaker 1: And it's in the southern hemisphere. So you looked in
30:14
Speaker 1: the direction of the constellation Irridanus, then that's the direction
30:19
Speaker 1: from which this light is extra cold. All right, So
30:23
Speaker 1: that there's a big cold spot in the sky, that
30:25
Speaker 1: my may tell us that the universe had a big
30:27
Speaker 1: cold spot when it was born. Maybe, So let's dig
30:30
Speaker 1: into that and let's talk about what it could mean.
30:33
Speaker 1: But first let's take another quick break, all right, the
30:48
Speaker 1: early universe had a cold spot, Daniel, possibly at least
30:51
Speaker 1: from what we can see right now. If we look
30:53
Speaker 1: out into the sky at the cosmic microwave background radiation,
30:56
Speaker 1: we see that there's one spot that is cold are
31:00
Speaker 1: than the rest of the universe. So what's going on? Yeah,
31:02
Speaker 1: it's a big cold spot. And you know, we can
31:05
Speaker 1: never really definitively no, because there are a few possible
31:09
Speaker 1: explanations and they range from like the total yawn fast
31:13
Speaker 1: boring explanation to like the crazy, mind blowing revealing the
31:17
Speaker 1: nature of reality kind of explanation. I mean, I guess
31:20
Speaker 1: which one you're hoping for, Not the boring one. I'm
31:23
Speaker 1: hoping for aliens. But there's no alien explanation for this one,
31:28
Speaker 1: not yet. But we still got fifteen minutes on this podcast. Well,
31:31
Speaker 1: we'll figure something out for you, or when we write
31:34
Speaker 1: our pitch script to Marvel, will include aliens somehow. Oh yeah,
31:39
Speaker 1: microwave guardians of the universe, Guardians of the micro universe.
31:44
Speaker 1: All right, So what are these possible explanations for this
31:47
Speaker 1: cold spot? Now? I know we see it out there
31:49
Speaker 1: in the microwave radiation, but do we think that it's
31:52
Speaker 1: like a hole through the universe or like a sphere
31:55
Speaker 1: out there of coldness what we think it looks like.
31:58
Speaker 1: Well there really there are two ethic explanations. One is
32:02
Speaker 1: that like the light was generated itself from a colder
32:05
Speaker 1: spot in the original plasma. And you know, we're talking
32:09
Speaker 1: about quantum effects here, and quantumness is random, and sometimes
32:13
Speaker 1: randomness gives you weird stuff. You know, if you flip
32:15
Speaker 1: a coin ten times, you do have a chance, however small,
32:18
Speaker 1: to get ten heads in a row. It can happen.
32:21
Speaker 1: And so one possible explanation is that those original quantum
32:25
Speaker 1: fluctuations in the early universe just happened to create a
32:28
Speaker 1: spot with less density of stuff, a slightly colder spot
32:32
Speaker 1: in the original plasma. Like maybe that that's just how
32:36
Speaker 1: the universe rolled, you know, or like that's what they
32:39
Speaker 1: got in their role playing character role when it determined
32:43
Speaker 1: would look like it just happened to have a cold spot. Yeah,
32:46
Speaker 1: it's possibility. That's one explanation. Yeah, it's sort of like
32:48
Speaker 1: a non explanation. But you know, every time you have
32:52
Speaker 1: random effects and you have a statistical distribution, you never
32:55
Speaker 1: really know, and so this is pretty unlikely. We can
32:58
Speaker 1: quantify how unlikely it is. We have a model for
33:01
Speaker 1: what those quantum fluctuations should have looked like. And just
33:03
Speaker 1: like you can calculate how likely is it to get
33:06
Speaker 1: ten heads in a row when you flip a coin,
33:08
Speaker 1: we can calculate how likely is it to see this
33:10
Speaker 1: coldest spot this size in the sky. You know, it's
33:14
Speaker 1: like a one in two hundred chants though it's like
33:17
Speaker 1: right on the edge there where it seems kind of improbable,
33:21
Speaker 1: but it's not impossible. You know, we only have this
33:23
Speaker 1: one universe. If we had a bunch of different universes
33:27
Speaker 1: and we have a bunch of different CMBs, we could ask,
33:29
Speaker 1: how often do you see something like this? Is it
33:31
Speaker 1: really wanting two hundred or is there something else going on? Right?
33:34
Speaker 1: Like if you had two hundred universes, one of them
33:36
Speaker 1: would probably have a cultpot just naturally exactly, yeah, And
33:40
Speaker 1: so you never know, like, did we just get a
33:42
Speaker 1: weird one? Do we have an odd universe in some way?
33:45
Speaker 1: Or do we not have an understanding for how that
33:47
Speaker 1: quantum random has happened and something else is going on?
33:51
Speaker 1: We really just don't know. So the most boring vanilla
33:53
Speaker 1: explanation is, you know, we just happen to get a
33:56
Speaker 1: weird universe. The most boring explanation is just oh, well,
34:02
Speaker 1: get what you get and you don't complain. And it's
34:04
Speaker 1: also sort of boring because it's not really like much
34:06
Speaker 1: to follow up on, like, well, it just is what
34:08
Speaker 1: it is, like, you know, sometimes you get double zero
34:10
Speaker 1: when you spind the wheel, and there's not much else
34:13
Speaker 1: to say about it unless you can prove that it
34:15
Speaker 1: is controlled by a different probability distribution than the one
34:18
Speaker 1: we expected. But if it is just sort of like
34:20
Speaker 1: a weird outlier, then hey, you know that happens, all right.
34:23
Speaker 1: Well then what's the next more interesting explanation. Well, the
34:26
Speaker 1: next more interesting explanation is that the CMB got cold
34:30
Speaker 1: as it flew to us. Remember we talked about how
34:33
Speaker 1: the light as it comes to us from where it
34:36
Speaker 1: was originally generated is affected by how much stuff there
34:40
Speaker 1: is in the universe, and so in that sense, looking
34:43
Speaker 1: at this light is a way to probe how much
34:45
Speaker 1: stuff there is between us and that original plasma. So
34:48
Speaker 1: if there's a really big cold spot in the CMB,
34:52
Speaker 1: it could mean that there's like a huge void of stuff.
34:56
Speaker 1: There's like a huge blob of space between us and
34:59
Speaker 1: that original plasma h that just like has nothing in it.
35:02
Speaker 1: M M, I see, because like an empty void like
35:05
Speaker 1: that would cool the MicroID background radiation. Right exactly as
35:09
Speaker 1: the light enters the void, it loses some energy. It's
35:11
Speaker 1: going to lose some energy because it's more like stuff
35:13
Speaker 1: behind it. And you know, we expect there to be voids,
35:16
Speaker 1: like we know that the structure of the universe is
35:19
Speaker 1: you start from stars, which form galaxies. Those galaxies form clusters,
35:23
Speaker 1: and those clusters themselves form these like walls and these
35:26
Speaker 1: filaments and these huge sheets around bubbles around big voids
35:31
Speaker 1: in which there is nothing, and those things are pretty big.
35:34
Speaker 1: But those voids would not explain this gap like you
35:38
Speaker 1: would need a super void, like a void the size
35:41
Speaker 1: of five angular degrees basically right, Yeah, like a humongous
35:45
Speaker 1: like multi galaxy empty space. Yeah, much bigger than multi galaxy.
35:50
Speaker 1: We're talking about something that's like a thousand times the
35:53
Speaker 1: volume of the voids. We see. This thing would have
35:55
Speaker 1: to be like billions of light years across some rediculously
36:00
Speaker 1: unusual spot in the universe that happens to just contain nothing. Yeah,
36:06
Speaker 1: I guess the big question would be, then where did
36:08
Speaker 1: this void come from, right, Because don't voids come from
36:11
Speaker 1: those original quantum fluctuations too? They do come from that
36:14
Speaker 1: exactly the way the universe gets its structure as you
36:16
Speaker 1: have those fluctuations, which then build on themselves because anything
36:20
Speaker 1: that has a little bit more density, that has a
36:22
Speaker 1: little bit more gravity, and so it's tugging more stuff
36:25
Speaker 1: in and then it gets denser and it's a runaway effect,
36:28
Speaker 1: and so the matter sends to clump together where there
36:31
Speaker 1: were original like over densities, and you tend to get
36:34
Speaker 1: voids where there were under densities. But that doesn't explain
36:37
Speaker 1: how you got that under density, right, sort of like
36:39
Speaker 1: again the same question, how is it possible that we
36:42
Speaker 1: look at and we see a bunch of voids of
36:44
Speaker 1: a particular size, but then there's one super duper void.
36:48
Speaker 1: How did that happen? Right? And it goes back to
36:50
Speaker 1: the same question almost right, like was there a big
36:53
Speaker 1: cold spot like that in the early plasma of the universe.
36:56
Speaker 1: It's almost the same question, isn't it. Yeah, it's almost
36:59
Speaker 1: the same question, but one would be even bigger. Right,
37:01
Speaker 1: In order to create this sort of cold spot, you
37:04
Speaker 1: need a really really massive void that would extend across
37:08
Speaker 1: a much bigger region of the universe. Such a void
37:11
Speaker 1: is like it's hard to gell with, Like our ideas
37:13
Speaker 1: about dark matter and dark energy, you just don't get
37:16
Speaker 1: this kind of thing. We've run lots of simulations of
37:18
Speaker 1: universe is and you never see this kind of structure.
37:22
Speaker 1: So this is maybe even more unlikely, but it would
37:24
Speaker 1: be more awesome for that reason. I guess the less
37:28
Speaker 1: likely it is, the more interesting it is scientifically to right, Yes, exactly,
37:33
Speaker 1: we want to see something weird that we can't explain
37:36
Speaker 1: with our current theories because that tells us how we
37:38
Speaker 1: might be able to change our theories and learn something
37:41
Speaker 1: new about the universe. We want to see our theories fail. Right.
37:44
Speaker 1: Scientists are not out there like my theory will win out.
37:47
Speaker 1: We're trying constantly to disprove our theories because that means
37:51
Speaker 1: finding a clue to solving the murder mystery of the universe.
37:55
Speaker 1: And so one thing people have done is like, well,
37:57
Speaker 1: let's look directly for this void. I mean, if there
38:00
Speaker 1: really is a huge gap in stuff out there, we
38:03
Speaker 1: could literally see it. Right, this is something we can
38:05
Speaker 1: see not just through the CMB, but by directly looking
38:09
Speaker 1: to see are there a bunch of galaxies missing, right,
38:11
Speaker 1: But we would have to be looking pretty far out, right,
38:14
Speaker 1: We would have to be looking pretty far out, but
38:16
Speaker 1: we can, right, we can look really far out into
38:18
Speaker 1: the universe. This is something which would exist in the
38:21
Speaker 1: universe between us and the edge of the observable universe.
38:25
Speaker 1: Because remember the CNB comes from almost the edge of
38:28
Speaker 1: the observable universe, and so it would have passed through
38:31
Speaker 1: this super void. So we should be able to see it.
38:34
Speaker 1: And how we've seen it. People looked and seen any
38:37
Speaker 1: big empty spaces we have looked, And in two thousand
38:41
Speaker 1: and fourteen, a study from University Hawaii actually did find
38:44
Speaker 1: a super void, like a really massive void, and they
38:47
Speaker 1: called it the largest individual structure identified by humanity, which
38:52
Speaker 1: is sort of hilarious because, like I keep seeing that
38:55
Speaker 1: in astronomy papers, people keep saying, this is the biggest
38:58
Speaker 1: thing in the universe. No, now, this is the biggest
39:00
Speaker 1: thing in the universe. It's like they're claim to fame. Yeah,
39:03
Speaker 1: but it technically it's the largest empty space they found, right, Yeah, exactly.
39:07
Speaker 1: It's like a bubble surrounded by galaxies and galaxy clusters
39:11
Speaker 1: with nothing inside it. So they found a really big
39:14
Speaker 1: super void roughly in the right direction, but it's not
39:18
Speaker 1: actually big enough, and it's not sort of voidy enough,
39:21
Speaker 1: like it needs to be like really empty of stuff
39:23
Speaker 1: in order to explain this cold shift. And if you
39:26
Speaker 1: take this super void and you think, well, what would
39:28
Speaker 1: happen to photons passing through it, they don't actually get
39:31
Speaker 1: chilled enough to explain the cold spot that we see
39:34
Speaker 1: explains like twenty or thirty microkelvins of cooling, not the
39:38
Speaker 1: full seventy to a hundred I see. So it's not
39:41
Speaker 1: cool enough this super void, this super void is too hot,
39:45
Speaker 1: not hot enough or cool enough sadly exactly, even though
39:49
Speaker 1: it lives in Hawaii, exactly Hawaiian. So it doesn't really
39:54
Speaker 1: match up like you'd love to see, like a massive
39:56
Speaker 1: super void just in the same direction that explained. That
40:00
Speaker 1: be a really sort of nice connection there, But this one,
40:02
Speaker 1: though it's interesting, doesn't actually explain the data. The two
40:05
Speaker 1: stories don't really fit together quite well enough. But that's
40:08
Speaker 1: just only what we've seen. Like there could still be
40:10
Speaker 1: a giant boyd, we just haven't seen it or been
40:12
Speaker 1: able to make it out. Yeah, exactly. There's always more
40:14
Speaker 1: stuff to look at in better telescopes and new ways
40:17
Speaker 1: to analyze the data. But we have not found a
40:19
Speaker 1: supervoid out there that explains this cold spot. All right,
40:23
Speaker 1: So then what's the craziest idea we have about this
40:26
Speaker 1: could spot? The craziest idea about this cold spot is
40:29
Speaker 1: that maybe it comes from even earlier in the universe.
40:32
Speaker 1: Maybe it comes from the very very birth of our universe.
40:36
Speaker 1: People talk about how the universe was made, and one
40:39
Speaker 1: possible explanation is that our universe is like a little bubble,
40:43
Speaker 1: a bubble of some pre universe stuff that decayed into
40:47
Speaker 1: normal matter. And here we are going way out into
40:50
Speaker 1: like crazy, no basis speculation for how the universe might
40:54
Speaker 1: have been formed, right, no data to support this. But
40:57
Speaker 1: it's possible that the universe sort of turn into normal
41:01
Speaker 1: matter from some sort of pre universe matter. They call
41:04
Speaker 1: this like the Inflaton field. And you have to imagine
41:07
Speaker 1: sort of like a meta universe filled with this stuff,
41:10
Speaker 1: which then, like birth's individual universes, so like our entire
41:13
Speaker 1: universe created in a little bubble inside this larger universe,
41:19
Speaker 1: along with other little bubbles exactly along with other little bubbles.
41:23
Speaker 1: Where do those bubbles get made? Well, it's quantum mechanical,
41:26
Speaker 1: so it's random. And sometimes those bubbles might be really
41:29
Speaker 1: close to each other and maybe bump up against each other,
41:33
Speaker 1: and if they did that, they might leave a mark
41:35
Speaker 1: on each other. You might get like evidence on your
41:38
Speaker 1: bubble that you bounced against another bubble. And in some
41:42
Speaker 1: of these theories, this effect this sort of like bruise
41:45
Speaker 1: on a universe, which show up as a cold spot,
41:49
Speaker 1: which would lead to a super void. Wait what you mean,
41:52
Speaker 1: like the ideas that these universe are being created in
41:55
Speaker 1: this froth of meta universe and sometimes the bubble bumping
42:00
Speaker 1: to each other and that would create a cold spot.
42:02
Speaker 1: When did it creates like I don't know, like a
42:04
Speaker 1: dent maybe more a dent is basically a cold spot.
42:08
Speaker 1: You know, it gets like suppressed, It gets like squeezed down,
42:11
Speaker 1: and you would expect actually a cold spot surrounded by
42:14
Speaker 1: like a little bit of a hot spot. You get
42:17
Speaker 1: like a hot ring inside of it a cold spot,
42:20
Speaker 1: And that's actually kind of what we see. Like if
42:22
Speaker 1: you look at this cold spot, it is cold, but
42:24
Speaker 1: the stuff around it is a little bit unusually hot,
42:27
Speaker 1: and so it sort of looks like a bruise on
42:30
Speaker 1: the cosmic microwave background from a parallel universe. And you know,
42:34
Speaker 1: again this is speculation on speculation, on speculation. There are
42:38
Speaker 1: many other possible explanations, and we have no evidence that
42:41
Speaker 1: there was this meta universe or other bubble universes. But
42:44
Speaker 1: it's sort of a fun idea, Like they have a
42:47
Speaker 1: model of this crazy multiverse and you can actually model
42:51
Speaker 1: like what happens when two universe is bumping to each other. Yeah,
42:54
Speaker 1: they do, although you know you have to wonder, like
42:56
Speaker 1: are these models designed to explain this cold spot? Is
43:00
Speaker 1: not like a prediction. This is sort of like more
43:03
Speaker 1: like a post adiction. It's not like fifty years ago
43:05
Speaker 1: people are saying we're going to discover the CNB and
43:08
Speaker 1: it's going to have a cold spot from the previous universe.
43:10
Speaker 1: It's more like a cold spot. I wonder if I
43:13
Speaker 1: could explain that using a parallel universe. So here's a
43:17
Speaker 1: theory I cooked up, and you probably like tweak the
43:19
Speaker 1: parameters until you get the cold spot, right. Yes, that's
43:22
Speaker 1: the tricky thing. And so what you got to do
43:24
Speaker 1: always when you make a theory that explains the data
43:27
Speaker 1: is then you have to predict future data so you
43:30
Speaker 1: can test your theory. Otherwise it's just an explanation. Wow. Alright, Well,
43:34
Speaker 1: so this big cold spot in the sky in the
43:37
Speaker 1: universe background radiation, it sounds like it's still a big mystery,
43:41
Speaker 1: like nobody really knows what could be causing it. It's
43:43
Speaker 1: still a mystery. It's still something people are puzzling over.
43:46
Speaker 1: There even crazier ideas out there that we didn't cover,
43:49
Speaker 1: things like cosmic texture and all sorts of weird stuff
43:52
Speaker 1: and aliens, aliens. Let's not forget aliens. Here's here's my
43:55
Speaker 1: alien theory, Daniel. They build a death star that's billions
43:59
Speaker 1: of light year across and that's what's causing the cold spot.
44:02
Speaker 1: It's blocking the CNB and it's coming our way. Yeah,
44:08
Speaker 1: and there's a one percent chance that I'm totally making
44:11
Speaker 1: it up. I love your theory. It sounds just about
44:14
Speaker 1: as plausible as the parallel universe theory. Yeah, there you go.
44:17
Speaker 1: I am right up there with the leading physicists on
44:19
Speaker 1: this matter. Yes, absolutely, you're on the cutting edge. But
44:22
Speaker 1: you're right, it could be nothing. It could just be
44:24
Speaker 1: like a random quantum fluctuation. But it's not something we
44:27
Speaker 1: currently understand, and so it could be that twenty years
44:30
Speaker 1: from now we look back and say, oh my gosh,
44:31
Speaker 1: that was the clue that told us something deep about
44:34
Speaker 1: how the universe works. Because remember, the CNB is filled
44:38
Speaker 1: with super rich information about how the universe came to
44:40
Speaker 1: be and how it evolved and why it looks the
44:43
Speaker 1: way it does today. So I wouldn't be surprised if
44:45
Speaker 1: this really, in the end taught us something deep about
44:47
Speaker 1: the universe. We just don't know what yet. Yeah, Or
44:50
Speaker 1: maybe the universe just doesn't like to talk about it,
44:52
Speaker 1: you know, maybe to lit embarrassed by that cold spot,
44:55
Speaker 1: in which case maybe we should just look away, Daniel,
44:57
Speaker 1: just ignore it. That's the polite thing that don't stare
45:00
Speaker 1: that ZiT on your friend's head, and I just pretend
45:02
Speaker 1: it's not there. Yeah, Yeah, that's what a good friend
45:06
Speaker 1: of the universe would do. All right. Well, again, just
45:08
Speaker 1: another reminder that the universe is all around us, it's
45:11
Speaker 1: giving us clues all the time, and that there are
45:14
Speaker 1: big cold spots of mystery in it, in that information
45:19
Speaker 1: that it's bathing as with exactly, they're big giant voids
45:22
Speaker 1: of knowledge that we still don't have about the universe. Yep.
45:26
Speaker 1: And we have figured out the c MB is there,
45:28
Speaker 1: but there's probably other kinds of information that we're swimming
45:32
Speaker 1: in right now that contains incredible facts about the origins
45:35
Speaker 1: of our universe. We just don't even know how to
45:37
Speaker 1: look for it and how to interpret it. In later
45:40
Speaker 1: generations will chuckle when they look back at how silly
45:43
Speaker 1: and how foolish we were. Right, maybe all we have
45:46
Speaker 1: to do is check the cmb R, not the cmb
45:49
Speaker 1: and we would have seen the answer. And we should
45:51
Speaker 1: have checked the CNBS and the c MBT. I mean, like,
45:54
Speaker 1: let's follow up on these things, all the Marvel movies
45:57
Speaker 1: right there. All right, Well, we hope you enjoyed the ad.
46:00
Speaker 1: Thanks for joining us, see you next time. Thanks for listening,
46:12
Speaker 1: and remember that Daniel and Jorge explained the universe is
46:14
Speaker 1: a production of I Heart Radio. For more podcast For
46:18
Speaker 1: my heart Radio, visit the I heart Radio app, Apple Podcasts,
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Speaker 1: or wherever you listen to your favorite shows. Ye