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What is the cosmic microwave background? · Daniel and Kelly’s Extraordinary Universe

0:08
Speaker 1: Crystal, did you know that the secrets of the universe
0:11
Speaker 1: are all around us? What? Where? No? I mean answers
0:16
Speaker 1: to some of the deepest questions in science are literally
0:19
Speaker 1: all around us, like hiding under my bed or what
0:23
Speaker 1: do you mean? Yeah, they're under your bed, but they're
0:25
Speaker 1: also just right here in the air between me and you.
0:28
Speaker 1: I guess Bob Dylan was right. What do you mean,
0:31
Speaker 1: Bob Dylan? They're all just blowing in the wind. I
0:34
Speaker 1: guess Bob Dylan was a poet and also secretly a
0:37
Speaker 1: physicist and a philosopher, Which aren't We are doctors a
0:41
Speaker 1: philosophy anyway. That's right. That doesn't mean we know anything
0:44
Speaker 1: about it, but we have the title. Hi. I'm Daniel.
1:03
Speaker 1: I'm a particle physicist and co host of the podcast
1:06
Speaker 1: Daniel and Jorgey Explain the Universe, brought to you by
1:10
Speaker 1: I Heart Review. My co host, the hilarious and good
1:14
Speaker 1: looking Jorge Cham is not here today to join us
1:17
Speaker 1: with his amazing jokes about bananas. He does love a
1:20
Speaker 1: good banana, He does love a good banana. But instead
1:24
Speaker 1: today we have a wonderful, amazing co host, Crystal Dilworth. Crystal,
1:28
Speaker 1: introduce yourself. Hello. I'm Dr Crystal Dilworth. I'm a neuroscientist,
1:34
Speaker 1: um my PhD s and molecular neuroscience, so the molecular
1:38
Speaker 1: basis of nicotine dependence from cal Tex. So I'm just
1:42
Speaker 1: a curious person that loves science communication and I'm super
1:45
Speaker 1: excited to be here to talk to you today. All right, well,
1:47
Speaker 1: thanks for joining us. So you studied nicotine addiction. Does
1:50
Speaker 1: that make you um in the pocket for big tobacco?
1:53
Speaker 1: It's a classic dilemma, right do you accept research funding
1:57
Speaker 1: from big tobacco? Um? I was supported by ni H,
2:01
Speaker 1: so I escaped that quandary, so you stayed clean. In
2:06
Speaker 1: my field, it's always a question of do you take
2:08
Speaker 1: money for weapons researchis you know, like my parents, for example,
2:11
Speaker 1: worked at National Labs, work in weapons programs and helped
2:14
Speaker 1: develop essentially weapons of mass destruction, whereas I try to
2:18
Speaker 1: stay away from that and work on things that will
2:20
Speaker 1: never affect anybody's life. So maybe there's a parallel there. Um.
2:24
Speaker 1: But Crystal, you are a PhD scientist, but you're also
2:28
Speaker 1: not just a scientist, right, You're a dancer, you're a
2:31
Speaker 1: movie star, You're I guess I should have led with that.
2:36
Speaker 1: So I became part of the PhD Comics universe, um
2:40
Speaker 1: through the PhD movie. So I played Tagel in the
2:43
Speaker 1: PhD movie and the PhD movie too, and that's how
2:46
Speaker 1: I sort of came into ys Orbit and we've been
2:49
Speaker 1: working together on and off to audition for a movie.
2:53
Speaker 1: I mean, you ever acted before? I had acted in
2:56
Speaker 1: children's theater, So nothing on camera, nothing serious that was
3:00
Speaker 1: going to be seen on every continent on the planet.
3:05
Speaker 1: And it was really hard for me because I had
3:07
Speaker 1: started grad school thinking I was going to give up
3:09
Speaker 1: my life in the performing arts. No more dance, no
3:11
Speaker 1: more theater, no no stages for me. I was going
3:14
Speaker 1: to be the best scientist anyone had ever seen. I
3:17
Speaker 1: was going to eat, sleep, breathe science, do the right thing,
3:22
Speaker 1: be a good person. Um. But I had been reading
3:26
Speaker 1: PhD comics since I was working in the lab. And
3:29
Speaker 1: when you get an email saying PhD Comics is coming
3:32
Speaker 1: to your campus and they want to make a movie,
3:35
Speaker 1: a live action movie or live action YouTube series about
3:39
Speaker 1: this comic that has been your you know, your inspiration
3:43
Speaker 1: for grad school? Do you want to be a part
3:45
Speaker 1: of And it's like therapy for people, right. And I
3:47
Speaker 1: traveled with or hate people who come up to him
3:49
Speaker 1: and say, it hadn't been for your comic, I would
3:51
Speaker 1: never have made it through grad school, right, I mean,
3:54
Speaker 1: if it hadn't been for the comic, I never would
3:56
Speaker 1: have gone to grad school. So that's that's a whole
3:59
Speaker 1: other conversation shin before then, to blame you for your
4:03
Speaker 1: grad school. Yes, they hold him very much to blame.
4:05
Speaker 1: I don't know if he knows that, Jorge, it's your fault, um,
4:09
Speaker 1: But yeah, it was just the carrot was too big.
4:11
Speaker 1: So I was I was at a Biophysics Society meeting,
4:16
Speaker 1: which is about three hours away from Pasadena at the
4:19
Speaker 1: time that Jorge was running auditions for the PhD movie,
4:24
Speaker 1: and I went to my last session, got in the car,
4:27
Speaker 1: drove from San Diego up to Pasadena audition for the movie,
4:31
Speaker 1: and then drove back so I could be there for
4:33
Speaker 1: my eight am poster session the next morning. Like my
4:36
Speaker 1: my advisor like as if as if I was never gone,
4:40
Speaker 1: he would never know. Yeah, And that was sort of
4:44
Speaker 1: the beginning of the end for me, because through working
4:46
Speaker 1: with Jorge, I discovered that science communication was an area
4:50
Speaker 1: that I could work in after grad school, and that's
4:53
Speaker 1: what I do now. I host a show for a
4:55
Speaker 1: Voice of America that highlights science and technology that's happening
4:58
Speaker 1: here in the United States. It's broadcast internationally. UM I
5:02
Speaker 1: was recently selected as one of the Triple A s
5:05
Speaker 1: if THEN Ambassadors. I'm a role model for women in STEM.
5:08
Speaker 1: Thank you, and I'm really excited about what that means.
5:11
Speaker 1: And I've you know, I love doing these types of things.
5:15
Speaker 1: I'm happy to sit down here with you and do
5:17
Speaker 1: you feel like people these days still have to sort
5:19
Speaker 1: of choose between having a career in science or having
5:22
Speaker 1: a career in sort of the creative sector art, dance,
5:24
Speaker 1: you know, public speaking, or do you think it's more
5:27
Speaker 1: opening now for people to bridge that gap and live
5:30
Speaker 1: two lives and not have to hide from their advisor
5:32
Speaker 1: that they're doing this other thing. I think that the
5:35
Speaker 1: Ivory Tower is still pretty restrictive in terms of what
5:39
Speaker 1: it will accept for its tenure track faculty. But I
5:43
Speaker 1: think that if you haven't chosen that as your path
5:46
Speaker 1: to walk, there's a lot more leniency. UM. You asked
5:50
Speaker 1: about careers. I think it's difficult to make a full
5:54
Speaker 1: living in the arts and a full living in science.
5:58
Speaker 1: So in that respect, Abe you would have to choose
6:01
Speaker 1: one or the other. But there's so many exciting spaces
6:04
Speaker 1: for collaboration. I don't feel that anyone should feel that
6:08
Speaker 1: they have to give one of those up in order
6:11
Speaker 1: to do the other. Well. I'm really excited about the
6:13
Speaker 1: idea that science could be more open to more kinds
6:15
Speaker 1: of people, not just people who look different or come
6:17
Speaker 1: from different places, but people whose interests are broader, and
6:20
Speaker 1: that we don't have to be only people who are
6:22
Speaker 1: super zero focused on exactly this one kind of science,
6:25
Speaker 1: and then they have other interests and they do other
6:27
Speaker 1: things in their life. I think that's probably going to
6:28
Speaker 1: be good for science and also good for science communication
6:31
Speaker 1: if we have people from science who know how to
6:33
Speaker 1: do this thing. In my lab, specifically, I encourage the
6:36
Speaker 1: students to do science communication, send them to conferences, this
6:39
Speaker 1: kind of thing. I don't know if that's good for
6:41
Speaker 1: their careers or not, but I figured, since I try
6:43
Speaker 1: to do science communication, that I should try to not
6:45
Speaker 1: prevent my students from also doing it. I don't know
6:48
Speaker 1: if that's a good idea or not, but on this
6:50
Speaker 1: open minded process I'm experimenting on my students, but also
6:56
Speaker 1: on this podcast, we want people to understand that everybody
6:59
Speaker 1: can understand scien It's one of the goals of this
7:01
Speaker 1: podcast is to zoom around the universe and take crazy,
7:03
Speaker 1: amazing things and make them actually understandable, not just jargon
7:07
Speaker 1: said while waving your hands, which isn't helpful on podcast,
7:10
Speaker 1: but people can go away and feel like I get it,
7:13
Speaker 1: I know what that is. I understand relativity now, and
7:15
Speaker 1: I want to make breakdown those barriers and make people
7:17
Speaker 1: feel like they can figure it out too. Oh I'm
7:20
Speaker 1: all for that, all right, So let's get into it today.
7:24
Speaker 1: We're gonna talk about something really amazing, as we alluded
7:26
Speaker 1: to earlier, something that's all around us, a secret of
7:29
Speaker 1: the universe, deep dark knowledge about how things in the
7:32
Speaker 1: universe work, the ancient history of the universe that has
7:35
Speaker 1: just been sort of floating around in the air around
7:37
Speaker 1: us with nobody noticing for I guess thousands of years.
7:41
Speaker 1: Literally like a color you can't see, yes, exactly, if
7:45
Speaker 1: only our eyes could open it. I talk a lot
7:47
Speaker 1: in this podcast about opening new eyes. I feel like
7:49
Speaker 1: science is always figuring out new ways to look at
7:52
Speaker 1: the universe, and every time we do so, we realize
7:54
Speaker 1: the universe. Wow. It looks so different and using these
7:57
Speaker 1: other eyes than than the ones we're familiar with. So yeah,
8:01
Speaker 1: it's like a color that we can't see. And also
8:03
Speaker 1: it's one of my favorite stories because it was discovered
8:05
Speaker 1: kind of by accident. You know, Folks were trying to
8:07
Speaker 1: do one thing, developed this technology, accidentally stumbled into this
8:11
Speaker 1: incredible wealth of knowledge about the universe. I think that
8:14
Speaker 1: there's a lot of really cool stories, especially in astro
8:19
Speaker 1: about accidental major discoveries. That seems to be one of
8:23
Speaker 1: the really big fields of science where that that's possible.
8:27
Speaker 1: I feel like I'm so jealous sometimes with astronomy because
8:30
Speaker 1: every time they look out into the universe with a
8:32
Speaker 1: new device, they find something that doesn't make any sense.
8:34
Speaker 1: We talked about recently the podcast These Fermi Bubbles. It's
8:37
Speaker 1: like huge structure the size of the galaxy and nobody
8:39
Speaker 1: ever seen before, found ten years ago. But whereas in
8:43
Speaker 1: particle physics it feels sometimes a little bit more difficult
8:46
Speaker 1: to find new things. It's rarer that we like find
8:48
Speaker 1: a new particle nobody hadn't expected. Um. So sometimes I'm
8:52
Speaker 1: jealous of astronomers because they get to they get to
8:54
Speaker 1: see things they don't understand more often, and that's like
8:57
Speaker 1: the launching point for discovery, right when the universe gives
9:00
Speaker 1: you a clue and says, here's something you didn't expect,
9:02
Speaker 1: then you get to unravel it. I feel like, for
9:04
Speaker 1: a chemistry and neuroscience, which are my area, is like
9:07
Speaker 1: the analogous story is like the discovery of LSD. Like
9:11
Speaker 1: some chemist was like, what's this? I'm going to eat it?
9:13
Speaker 1: And I was like, WHOA, Well that's the big leap
9:19
Speaker 1: forward in neuroscience. So what were they trying to do
9:23
Speaker 1: when they discovered LSD? I don't actually remember. It's like
9:26
Speaker 1: such an irrelevant part of the discovery story that I can't,
9:30
Speaker 1: off the top of my head even remember what they
9:31
Speaker 1: were trying to synthesize. Al Right, well, today we're talking
9:35
Speaker 1: about something unseen but then discovered something a surprisingly revealed
9:39
Speaker 1: that told us deep knowledge about the universe. So let's
9:42
Speaker 1: not tease it anymore. Today we're going to be answering
9:44
Speaker 1: the question what is the cosmic microwave background? So this
9:55
Speaker 1: is something which is invisible and carries a huge amount
9:57
Speaker 1: of information all around us, and it discovered by accident
10:01
Speaker 1: about fifty years ago. It's a pretty funny story. Actually,
10:04
Speaker 1: some folks were building a radio telescope to do something else.
10:07
Speaker 1: They want to do radar and communication, and so they
10:11
Speaker 1: built this device and then they heard this buzz on
10:14
Speaker 1: the device. Is this noise? And at first they were like, oh,
10:17
Speaker 1: this is annoying and we can't get rid of it.
10:19
Speaker 1: They thought it was like a malfunction of their telescope.
10:23
Speaker 1: Um they couldn't understand where it came from. So microwaves,
10:28
Speaker 1: can we just start there? I have one. I so
10:33
Speaker 1: you're an expert in microwave backgrounds because you can use
10:35
Speaker 1: a microwave. I can use a microwave. I'm an expert microwaver.
10:40
Speaker 1: I'm not sure how to extrapolate my knowledge of heating
10:43
Speaker 1: up soup to the beginning of the universe. Can you
10:47
Speaker 1: help me draw that connection? Yes, for once our podcast
10:51
Speaker 1: will actually have practical knowledge and it folks. Yes, we'll
10:54
Speaker 1: draw that connection. But first I was wondering what everybody
10:56
Speaker 1: knew about microwaves, Like, do people understand microwave back ground radiation?
11:00
Speaker 1: Dos that make sense to them? Is this something everybody
11:02
Speaker 1: is already familiar with or is it something nobody had
11:04
Speaker 1: ever heard of before? And so, as usual, I walked
11:07
Speaker 1: around campus here you see Irvine, and I'm eternally grateful
11:10
Speaker 1: to the students here for being open to being asked
11:13
Speaker 1: these random questions by a scruffy looking physicist. So before
11:17
Speaker 1: you hear their answers, think to yourself, do you know
11:20
Speaker 1: what the cosmic microwave background is? How could you explain
11:22
Speaker 1: it to a random dude who accosted you on the street.
11:26
Speaker 1: Here's what, folks that you see Irvine had to say
11:28
Speaker 1: something that's ongoing in the atmosphere having to do with microwaves.
11:36
Speaker 1: I don't know, no micro waves that are present everywhere.
11:40
Speaker 1: I do not know. I've heard the topic. I've watched
11:42
Speaker 1: couple of videos, but I don't understand that whatsoever. Wave
11:45
Speaker 1: like yeah, I don't know it's material or just wave.
11:48
Speaker 1: There is something like that a president outside Okay, I
11:52
Speaker 1: don't know. It's a elemnent of those in a big thing.
11:54
Speaker 1: All right, So Crystal, what do you think of those answers?
11:56
Speaker 1: You impressed? Um, I don't think i'd say impressed. But
12:01
Speaker 1: there's quite a diversity of topics that the answers are
12:05
Speaker 1: connecting to, like electricity or something. Yes, yeah, well, it's
12:10
Speaker 1: like electricity or something that's a pretty broad answer, so
12:13
Speaker 1: it's pretty close. You could tell that some people had
12:15
Speaker 1: no idea what we're talking about and just sort of
12:17
Speaker 1: guest generally physics. A few people had heard of it.
12:20
Speaker 1: I like think, I said, I watched a couple of videos,
12:22
Speaker 1: but I have no idea what it is that tells
12:25
Speaker 1: me that there's an opening here to really explain the
12:27
Speaker 1: microwave background. She really needs this podcast, Yes, exactly, this
12:30
Speaker 1: one is for you, dude. But I like the I
12:34
Speaker 1: like this answer remnant of the Big Bang. I mean,
12:37
Speaker 1: we're really getting to something there, aren't we. Yes, absolutely,
12:40
Speaker 1: somebody definitely knew what we were talking about. So let's
12:43
Speaker 1: get back to your question and break it down. I
12:46
Speaker 1: know how to heat up soup in a microwave. I
12:49
Speaker 1: even know that microwaves are long radio waves. I think
12:53
Speaker 1: of them as really big waves. I mean, I'm a
12:56
Speaker 1: I did a lot of fluorescence microscopy UM in a lab,
12:59
Speaker 1: so I like nanometer is a scale that I'm used
13:03
Speaker 1: to dealing with in microwaves, I think of being so
13:05
Speaker 1: big as to be ineligible. UM, so help me out here. Yeah,
13:10
Speaker 1: I love this sense of scales and science right for me.
13:12
Speaker 1: For example, anything big on the proton is like way
13:15
Speaker 1: too big and complicated even think about, right, whereas mechanical
13:19
Speaker 1: engineers never think about the individual molecules. So microwaves is
13:23
Speaker 1: really really just a relative term. Remember, microwaves are electromagnetic radiation,
13:28
Speaker 1: just like light. So everything that's coming into your eyeballs
13:31
Speaker 1: is electromagnetic radiation, but it's part of a much larger spectrum.
13:35
Speaker 1: The visible light is just this one little slice that
13:37
Speaker 1: we happen to be able to see because our eyes
13:39
Speaker 1: react to it. But down the lower um frequency, the
13:43
Speaker 1: longer wavelengths, you have radio waves, and at the higher
13:45
Speaker 1: end you have gamma rays and X rays. It's all
13:48
Speaker 1: just part of the same big electromagnetic family. And microwaves
13:52
Speaker 1: are a kind of radio waves, as you said, and
13:54
Speaker 1: they're might be called micro because they're short for radio waves.
13:57
Speaker 1: Radio waves can have wavelengths like meters long. It's just
14:00
Speaker 1: all about scale, it's all about scales, and so compared
14:03
Speaker 1: to that, microwaves, which have wavelength like millimeter, are really small.
14:06
Speaker 1: But of course you know, they're huge compared to visible
14:09
Speaker 1: light or gamma rays or anything that I know anything about. Frankly,
14:14
Speaker 1: So microwaves are mega waves for me and microwaves for
14:17
Speaker 1: most people. So cosmic microwave background. The connection is the
14:21
Speaker 1: wavelength of the electromagnetic radiation. And we talked on this
14:24
Speaker 1: podcast recently about how microwaves work, and they work in
14:27
Speaker 1: the same way. They pump this same kind of radiation
14:30
Speaker 1: into your soup to make it hot, using it to
14:33
Speaker 1: add energy to the system. That's right, Um, and then
14:36
Speaker 1: fueling you so that you can think about the universe
14:38
Speaker 1: and reveal all of its secrets. I'll work on that,
14:41
Speaker 1: all of the secrets revealed. Yeah, exactly. Um, Jorge usually
14:45
Speaker 1: has a banana before every podcast because apparently he can't
14:48
Speaker 1: think without a Is that's something you know about him
14:50
Speaker 1: through I know that he definitely does not operate without
14:53
Speaker 1: a banana. I do not operate without a coffee. So
14:56
Speaker 1: as long as he's got bananas and I've got coffee,
14:59
Speaker 1: we're usually good to go. That's all that's required around here. Well,
15:02
Speaker 1: this is a perfect spot to take a break. We'll
15:04
Speaker 1: be right back. Um. Yeah, So, cosmic microwave background radiation.
15:20
Speaker 1: The microwave radiation part just refers to the length of
15:23
Speaker 1: the waves of the electromagnetic radiation. So where are the
15:25
Speaker 1: waves coming from? Yeah, they're coming from everywhere, Like if
15:29
Speaker 1: you look out into the sky, you see this radiation
15:33
Speaker 1: coming from everywhere. And that was the weird thing about
15:35
Speaker 1: their discovery. When they turned on this radio telescope for
15:38
Speaker 1: the first time, they heard this buzz and they heard
15:41
Speaker 1: it from every direction. There's sort of two answer parts
15:44
Speaker 1: to that answer. One is where do we see them? Right,
15:46
Speaker 1: And it's coming from every direction, so we see it
15:48
Speaker 1: from everywhere in the sky. And often if you see
15:51
Speaker 1: a map of the cosmic microwave background radiation, it's this
15:54
Speaker 1: weird ellipse with these little dots on it, and that's
15:56
Speaker 1: an attempt to describe what you see in each direction
16:00
Speaker 1: the sky. So, because the sky is a circle, right,
16:03
Speaker 1: the Earth is a sphere. It's hard to map a
16:05
Speaker 1: sphere onto a flat piece of paper. The best way
16:08
Speaker 1: to describe what you see is if you could print
16:10
Speaker 1: it on the inside of a sphere, so you could
16:12
Speaker 1: look at and say, oh, in this direction, we see this.
16:14
Speaker 1: In that direction, we see this. The same way, it's
16:16
Speaker 1: hard to make a map of the stars you see
16:18
Speaker 1: in the sky, right. The best way to do that
16:20
Speaker 1: is like a planetarium, you can print them on the
16:22
Speaker 1: inside of a curved surface, so you can show what
16:25
Speaker 1: we're seeing. So what we see when we talk about
16:28
Speaker 1: the cosmic microwave background is we see this buzz, this
16:31
Speaker 1: electromagnetic radiation from every direction at once, so just filling
16:36
Speaker 1: the space that is the universe. Yeah, it's coming from
16:39
Speaker 1: every direction and hitting us. And it's everywhere. Like if
16:42
Speaker 1: we were here or around Jupiter, or in the center
16:45
Speaker 1: of the galaxy or in between galaxies, we would see
16:48
Speaker 1: it everywhere. So it's originating from the universe. It's just
16:52
Speaker 1: an energy that now exists and bounces around and comes
16:56
Speaker 1: from everywhere. Yeah, it comes from everywhere. And that's the
16:59
Speaker 1: confused seeing part, I think to a lot of people,
17:01
Speaker 1: because people think, Okay, it's light, so it's traveling at
17:04
Speaker 1: light speed and it's getting here. How can it be
17:07
Speaker 1: getting here? Where did it come from? Right? And that's
17:10
Speaker 1: pretty confusing if you imagine that, if you think about
17:13
Speaker 1: the beginning of the universe as a point and from
17:15
Speaker 1: that point things flew outwards, and people trying to imagine, well,
17:18
Speaker 1: then if it's getting here now it's coming from that point,
17:22
Speaker 1: how can we be seeing it from two directions? And
17:24
Speaker 1: the reason that's confusing is that I think that's the
17:26
Speaker 1: wrong way to think about the start of the universe.
17:28
Speaker 1: Oh my gosh, how should I be thinking about the
17:30
Speaker 1: start of the universe. Well, you start with the bowl soup, right, Um. No.
17:35
Speaker 1: The way I think about the start of the universe
17:36
Speaker 1: is that it started off infinite, that it's the moment
17:40
Speaker 1: of creation is not a single point in space, but
17:42
Speaker 1: that the Big Bang happened everywhere all at once. There
17:46
Speaker 1: was sort of multiple starts from every direction. And what
17:49
Speaker 1: we're seeing now is leftover bits from really far away
17:52
Speaker 1: in that in one direction, and really far away in
17:54
Speaker 1: the other direction. So if I'm looking at the cosmic
17:57
Speaker 1: microwave background reradiation, I'm seeing light that came from the
18:01
Speaker 1: very beginning of the universe. It took almost fourteen billion
18:03
Speaker 1: years to get here from somewhere really far away in
18:05
Speaker 1: one direction. And I'll turn around and I look in
18:08
Speaker 1: the other direction. I'm seeing light come from the other direction,
18:11
Speaker 1: which came really far away from the other direction, from
18:13
Speaker 1: somewhere else, really really far away. So these two pieces
18:17
Speaker 1: of light haven't talked to each other ever. Are they
18:20
Speaker 1: meeting for the first time in the history of the
18:22
Speaker 1: universe here on Earth. So they're not coming from the
18:26
Speaker 1: same place. It's not like we're looking at a little object.
18:29
Speaker 1: We're looking at a huge universe at its beginning. Every
18:33
Speaker 1: direction you look at, you're looking at a different part
18:35
Speaker 1: of the early universe. So does that mean that the
18:38
Speaker 1: different particles, the different waves of light that are meeting
18:41
Speaker 1: here for the very first time can tell us different
18:43
Speaker 1: things about the beginning of the universe. Yes, absolutely, they
18:47
Speaker 1: tell us what was going on at one spot of
18:49
Speaker 1: the universe over there, and what was going on at
18:50
Speaker 1: one spot of the universe over there, just the same
18:53
Speaker 1: way when we look at the night sky. Now you
18:55
Speaker 1: look at one star, it's telling you that light is
18:57
Speaker 1: telling you what happened a long time ago in that direction.
19:00
Speaker 1: You turn another way, and like from another star is
19:02
Speaker 1: telling you what happened in a totally different part of
19:04
Speaker 1: the universe, also a long time ago. Those two photons
19:07
Speaker 1: are also meeting for the first time. So I have
19:09
Speaker 1: a lot of questions about how that information is carried
19:13
Speaker 1: and decoded. But first I'd like to ask, when this
19:18
Speaker 1: background radiation was discovered, what did we think it was.
19:22
Speaker 1: How did we know that it could teach us and
19:24
Speaker 1: tell us things. Yeah, if that's a really fun part
19:27
Speaker 1: of the story because the guys who discovered this, they
19:29
Speaker 1: weren't looking for it, but there was another team of
19:32
Speaker 1: people who were looking for it, and they got scooped.
19:35
Speaker 1: So there was a team around the corner. This telescope
19:37
Speaker 1: they built was in New Jersey and it just happened
19:40
Speaker 1: to be around the corner from Princeton. It was a
19:41
Speaker 1: team of Princeton who was looking for this radiation. They
19:44
Speaker 1: were like scrambling to build the device. They could see it,
19:46
Speaker 1: and they got scooped by these guys who were like
19:48
Speaker 1: building something to do something else. The reason they were
19:51
Speaker 1: looking for it is that there was this idea that
19:52
Speaker 1: we could find evidence for the Big Bang. And this
19:55
Speaker 1: is back in the sixties when the Big Bang was
19:57
Speaker 1: still like kind of a crazy idea, not neces serily
20:00
Speaker 1: totally accepted. Definitely not a television show, yeah, not yet,
20:04
Speaker 1: a hilarious television show that probably gates stereotypes about scientists. Um.
20:10
Speaker 1: But the idea was that if the universe had started
20:14
Speaker 1: smaller or more dense right at the universe had started
20:17
Speaker 1: from um really dense mass and then exploded, then originally
20:22
Speaker 1: it was sort of hotter and denser. And the reason
20:25
Speaker 1: people thought that this radiation might exist. Is that they
20:28
Speaker 1: looked back into the history of the universe. They said, Okay,
20:31
Speaker 1: the universe now is a bunch of stars and galaxies,
20:33
Speaker 1: but if there had been a big bang, then the
20:36
Speaker 1: universe we sort of rewind the history of the universe.
20:39
Speaker 1: Everything pulls together and gets hotter and denser, and eventually
20:42
Speaker 1: it gets so hot and dense that it becomes a plasma.
20:45
Speaker 1: And a plasma is really interesting because light can't just
20:48
Speaker 1: passed through it. It's opaque. So this this moment in
20:51
Speaker 1: the history of the universe they thought when the universe
20:53
Speaker 1: went from opaque like like couldn't go through it too transparent,
20:56
Speaker 1: Suddenly the universe cooled um and became crystal clear, so
21:00
Speaker 1: that you could, like photons could fly through the universe
21:02
Speaker 1: without necessarily getting absorbed. And so this is this last
21:06
Speaker 1: moment when the universe was a hot plasma and then
21:08
Speaker 1: it cooled, and the light from that moment, they figured
21:10
Speaker 1: should still be around. That's crazy. I know. It's like, um,
21:14
Speaker 1: you know your baby picture that your parents took, you
21:17
Speaker 1: know whatever, years ago. Um, the light from that picture
21:20
Speaker 1: is still out in space somewhere. Like that's literally true.
21:23
Speaker 1: I was thinking, like gestational periods of the universe, which
21:27
Speaker 1: was like a really weird mental trip that I just
21:30
Speaker 1: went on and back. Now, okay, welcome back, um. But
21:35
Speaker 1: you know the same way that everything that happened on
21:37
Speaker 1: Earth a long time ago, the light from that is
21:39
Speaker 1: out there in space, the way like TV shows that
21:41
Speaker 1: we broadcast are out there in space flying away. Um,
21:44
Speaker 1: everything that happened in the early universe is still out
21:46
Speaker 1: there in space. So if the early universe used to
21:48
Speaker 1: be hot and dense and then all of a sudden
21:50
Speaker 1: became cool, then this light could fly through the universe
21:54
Speaker 1: untouched and it should still be out there. And that's
21:56
Speaker 1: what they were looking for. They were looking for this
21:58
Speaker 1: last light from the hot plasma other early universe, which
22:01
Speaker 1: should then still just be flying around and we should
22:04
Speaker 1: be able to find it. And you know microwave background.
22:06
Speaker 1: Remember that's just another kind of electromagnetic radiation. So when
22:09
Speaker 1: we're talking about light, we really just mean electromagnetic radiation.
22:13
Speaker 1: So finding this radiation meant that we were on the
22:16
Speaker 1: right track in terms of the origins of the universe model. Yeah,
22:20
Speaker 1: it was really the first experimental evidence that said, wow,
22:24
Speaker 1: this crazy idea that the universe used to be hot
22:26
Speaker 1: and dense and then expanded really fast. Might be true.
22:29
Speaker 1: It's you know, this rhythm and science where we say, okay,
22:31
Speaker 1: you've got a crazy idea that sort of explains the
22:33
Speaker 1: way things work. Make a prediction, prove it, predict something
22:38
Speaker 1: that we could find that we could only see if
22:40
Speaker 1: your idea is correct. And this is what was the prediction.
22:43
Speaker 1: And coincidentally, Jim Peebles, one of the guys who predicted it,
22:47
Speaker 1: just won the Nobel Prize for that prediction this very week.
22:51
Speaker 1: The competing idea at the time was the sort of
22:52
Speaker 1: steady state universe. Universe had been like this, been like
22:56
Speaker 1: this forever. You know, maybe it was expanding, but there's
22:59
Speaker 1: some sort of new source so stuff in it, and
23:02
Speaker 1: that people wanted to believe that. I don't really understand
23:04
Speaker 1: why people wanted to believe Biblical origins. Don't you think
23:08
Speaker 1: we'll see but biblical origins tell you the universe had
23:10
Speaker 1: a beginning, right, The steady state idea sort of like
23:13
Speaker 1: the eternal universe. The universe has been like this forever,
23:17
Speaker 1: And for some reason, I think that seemed more natural
23:19
Speaker 1: to people. It seems more natural to me that the
23:21
Speaker 1: universe had a beginning. I guess to some people, thinking
23:24
Speaker 1: the universe had an origin brought up other questions like
23:27
Speaker 1: what happened before that? And I'm not afraid of questions.
23:29
Speaker 1: I love those questions, But to me, it would be
23:31
Speaker 1: weird at the universe it existed forever. I was actually
23:34
Speaker 1: trapped at the Caldec Faculty Club while a visiting professor
23:39
Speaker 1: and one of our staff scientists had an argument over
23:43
Speaker 1: what came before the Big Bang, and none of the
23:45
Speaker 1: graduate students were willing to interrupt the argument to say like,
23:49
Speaker 1: can we order because we're really hungry, and the waiter
23:53
Speaker 1: kept coming to take our order, and the graduate students
23:55
Speaker 1: kept making eyes at them like were we we can't
23:59
Speaker 1: They're still argue. Eventually, I think somebody came and was like, sirs,
24:04
Speaker 1: can we move this process along? But I guess this
24:07
Speaker 1: is still a hotly contested idea, at least in the
24:10
Speaker 1: Caltec fact of the club at lunchtime. Yeah, and you know,
24:13
Speaker 1: sometimes this arguments can feel like they last forever um.
24:16
Speaker 1: But at the time there was these two camps. It
24:18
Speaker 1: was the steady State University. University existed sort of in
24:21
Speaker 1: this similar state forever, and the other idea that it
24:23
Speaker 1: came from this hot, dense initial point. And this was
24:26
Speaker 1: the prediction that that they made that if the universe
24:29
Speaker 1: had been hotter and denser, it would have be this
24:31
Speaker 1: plasma and it would admit this radiation and we could
24:34
Speaker 1: still find it. You know, it's like if you, um,
24:37
Speaker 1: if there had been a rave in an apartment last night,
24:40
Speaker 1: and you know, you expect like lots of loud music,
24:42
Speaker 1: and the moment that music turns off, that music is
24:44
Speaker 1: still flying out there somewhere. So this is like saying,
24:47
Speaker 1: let's go find that music as evidence that there was
24:49
Speaker 1: a rave in my apartment last night, But of course
24:52
Speaker 1: that music is flying off away from us. You would
24:55
Speaker 1: have to like travel the speed of sound to catch it.
24:57
Speaker 1: This is like that we're finding here. So I think
25:00
Speaker 1: it can be a little confusing to digest, like why
25:02
Speaker 1: are we seeing that light here? And seeing it from
25:04
Speaker 1: multiple directions. So when it was detected or discovered, the
25:10
Speaker 1: scientists knew what they had, and they also knew that
25:13
Speaker 1: there were some were going to be some really upset
25:15
Speaker 1: people at Princeton Um. They didn't know what they had,
25:19
Speaker 1: Like the guys who found it, Penzias and Wilson, they
25:22
Speaker 1: just thought it was noise. They just heard this hiss
25:25
Speaker 1: in their telescope and it was an obstacle to them.
25:27
Speaker 1: They thought, we can't get rid of this. What was
25:28
Speaker 1: going on? Um? And they're like, this is really strange.
25:32
Speaker 1: And then they went around the corner to the physicist
25:34
Speaker 1: of Princeton and they're like, we found this weird thing.
25:36
Speaker 1: What do you know about it? And I think the
25:38
Speaker 1: physicist must have been like, oh my god, we've been
25:40
Speaker 1: trying to find this and you scooped us slash. Wow, wonderful,
25:43
Speaker 1: we learned this amazing thing about the universe. That must
25:46
Speaker 1: have been a really sort of you know, plus and
25:48
Speaker 1: minus moment for them. So they published it separately. There
25:52
Speaker 1: was no post talk collaboration. Now they wrote two papers.
25:56
Speaker 1: The guys who actually found it published their discovered, like
25:58
Speaker 1: here's what we found, and then immediately afterwards the Princeton
26:00
Speaker 1: guys wrote a paper saying here's what this means and
26:03
Speaker 1: here's why it's important. But the Penzias and Wilson, they're
26:06
Speaker 1: the ones who got the Nobel Prize because they're the
26:08
Speaker 1: ones who found it. Man, science sometimes it's luck, yes,
26:12
Speaker 1: I know, And you can be like days or weeks
26:14
Speaker 1: away from a discovery that wins the Nobel Prize, if
26:18
Speaker 1: those folks at Princeton, if their grad students had worked
26:20
Speaker 1: a little harder, or they hadn't taken us along to
26:22
Speaker 1: order lunch. Professor. When I was an undergrad professor of
26:31
Speaker 1: mine who was teaching thermodynamics, he was one of the
26:33
Speaker 1: folks racing to discover the Bose Einstein condensate, this weird
26:36
Speaker 1: state of matter, and there were other groups. Was when
26:39
Speaker 1: m I T and when it nised and he was
26:41
Speaker 1: able to create the Bose Einstein condensate and published it,
26:45
Speaker 1: but he was two weeks too late, and he was
26:48
Speaker 1: left out of the Nobel Prize. So there was shared
26:50
Speaker 1: between NIST and M I. T. And he was two
26:52
Speaker 1: weeks away from the winning the Nobel Prize. And I
26:54
Speaker 1: always thought, wow, that must be tragic, and he must,
26:57
Speaker 1: you know, wonder like should I have given my grad
26:58
Speaker 1: students two weeks off for Chris Smiths or we could
27:01
Speaker 1: all be sharing the Nobel Prize right now? Right, I
27:04
Speaker 1: feel like we should probably move on because I could,
27:07
Speaker 1: I could take this topic my soapboxman really want to
27:11
Speaker 1: be you know right now. But it's true, right, like
27:15
Speaker 1: these these things can be so so far yet so close,
27:21
Speaker 1: and you never know. You never know if you're around
27:22
Speaker 1: the corner from discovering something amazing, and also if somebody
27:25
Speaker 1: else is one week ahead of you, or if you're
27:27
Speaker 1: sort of on your own and you're about to discover
27:29
Speaker 1: this incredible thing. That's the pressed grad students showing up
27:34
Speaker 1: in the lab every day, right, is the hope that
27:37
Speaker 1: the next day is going to be different. It's also
27:38
Speaker 1: the definition of insanity. That's right slash of research. So
27:43
Speaker 1: when the Princeton group published sorry to bring us back,
27:46
Speaker 1: when the Princeton Group published their paper saying this is
27:50
Speaker 1: what the discovery means, what did it mean? Yeah, it
27:54
Speaker 1: meant that there was this evidence that the universe had
27:57
Speaker 1: once been hot and dense, and since the universe is
28:00
Speaker 1: dot hot and dense right now, it's like huge and
28:02
Speaker 1: empty and cold. That means that the period of the
28:04
Speaker 1: universe we're living in is not the way things have
28:06
Speaker 1: always been, and it means that the history is quite different.
28:09
Speaker 1: And we found relics of the history. This is like
28:12
Speaker 1: fossils of the universe. It's like a discovering whoy there
28:15
Speaker 1: there used to be these huge, crazy animals that walked
28:17
Speaker 1: along the Earth. Earth used to be totally different from
28:19
Speaker 1: what we're experiencing now. Now this is on the universe scale.
28:23
Speaker 1: Now we learned whow the universe used to be this hot, dense, nasty,
28:26
Speaker 1: wet plasma where nothing could probably get through and then
28:29
Speaker 1: it cooled. And so that was really very convincing um
28:33
Speaker 1: evidence that the Big Bang was a real thing, and
28:35
Speaker 1: the Big Bang like happened. It's not just an idea,
28:38
Speaker 1: it's not just a story. It's not just something you
28:39
Speaker 1: read about in the book. It was reality. It was
28:42
Speaker 1: it was these physical events took place. H And to me,
28:45
Speaker 1: that's amazing. You know that there's there's this history of
28:48
Speaker 1: the universe and we can uncover it, that there's enough
28:51
Speaker 1: clues out there that we can actually figure out what
28:54
Speaker 1: the objective truth is of the universe, which has sort
28:57
Speaker 1: of been like a big question in human existence, right
29:00
Speaker 1: where do we come from? How has this whole thing
29:02
Speaker 1: been created? We're unraveling that. We're like using science to
29:05
Speaker 1: figure out what the true history of the universe is.
29:07
Speaker 1: That's incredible power. So when you're talking about objective truth,
29:12
Speaker 1: is this things that can be described using mathematics. Yeah,
29:16
Speaker 1: we have models that described the early universe, and those
29:20
Speaker 1: models made predictions, and those predictions are born out to
29:22
Speaker 1: be true. And you know, we can never really claim
29:25
Speaker 1: objective truth. We don't really know what's out there. You
29:27
Speaker 1: can just be trapped in a brain, in a vat somewhere.
29:30
Speaker 1: You don't know if the universe exists. But assuming that
29:32
Speaker 1: the things that we're experiencing are real and that physics
29:35
Speaker 1: can describe them, we're making incredible progress in revealing the
29:39
Speaker 1: way we think the earlier universe happened. And I think
29:42
Speaker 1: that's pretty incredible. As a physicist, you know that there
29:48
Speaker 1: is a noable truth that is always true, at least
29:52
Speaker 1: within the universe that you yourself are experiencing. Yeah, that's
29:56
Speaker 1: one of the things I like about physics. I mean,
29:58
Speaker 1: I love doing creative stuff also, But the thing I
30:00
Speaker 1: like about physics is that the universe answers questions and
30:04
Speaker 1: it's you know, yes or no. It's not like, well, uh,
30:07
Speaker 1: you know, you wrote this thing, this novel and it's
30:09
Speaker 1: pretty good and somebody else's no, it's wonderful, somebody else's no,
30:12
Speaker 1: it's trash. Right, the universe, you can ask a question
30:14
Speaker 1: to say, all right, which theory is correct? And he
30:16
Speaker 1: says this one and that one. You love it. It's beautiful,
30:19
Speaker 1: but it's wrong. There's an objectivity there. It's not just
30:23
Speaker 1: people's opinion. You know, the universe tells you this is
30:26
Speaker 1: the way things happen. But only if you can find
30:29
Speaker 1: those clues, only if you can figure out a way
30:31
Speaker 1: to sort of corner the universe and make it reveal
30:33
Speaker 1: this truth. You don't just get to stand in a
30:35
Speaker 1: mountaintop and say, tell me the answers. You have to
30:37
Speaker 1: figure out a way to find these clues and on
30:40
Speaker 1: earth it like a detective and that's a slow process. Right.
30:42
Speaker 1: If you think about early interpretation of physical fossils like
30:48
Speaker 1: you know, dinosaurs, et cetera, or you know small ce creatures.
30:51
Speaker 1: We use that to fuel stories of monsters and uh,
30:56
Speaker 1: it evolved the way that we were describing our universe
31:00
Speaker 1: are our world, but not necessarily to bring it completely
31:02
Speaker 1: in line with the scientific understanding we have now. So
31:06
Speaker 1: how long did that process take discovering this fossil of
31:09
Speaker 1: microwave background? Yeah? Well, I think the idea of the
31:12
Speaker 1: Big Bang dates to the earlier part of the last century.
31:16
Speaker 1: The whole idea that the universe was bigger than the
31:18
Speaker 1: galaxy is only than only a hundred years old, and
31:21
Speaker 1: then so discovering these other galaxies, finding that they're moving
31:24
Speaker 1: away from us, and then trying to understand, well, if
31:26
Speaker 1: the universe, if galaxies are moving away from us, right,
31:30
Speaker 1: then how can we have a at all a sort
31:32
Speaker 1: of steady state model? Thing? Before that people imagine galaxies
31:35
Speaker 1: just sort of hanging in space. So then discover things
31:37
Speaker 1: are moving away from us, that's sort of immediately implies
31:40
Speaker 1: some sort of expansion. And then that brought up these
31:43
Speaker 1: questions like, well, how can you have expansion if the
31:45
Speaker 1: universe is bajillions of years old? And Einstein didn't like
31:49
Speaker 1: that at all either. That's really the origin of that idea.
31:52
Speaker 1: And so then to find this evidence is really conclusive.
31:55
Speaker 1: And then they discovered on top of all that evidence
31:57
Speaker 1: that this is really from the Big Bang. There's a huge,
32:00
Speaker 1: huge amount of detailed information in this buzz, in this
32:03
Speaker 1: light from the first plasma that gives us clues about
32:06
Speaker 1: what was happening in the Big Bang, the way like
32:08
Speaker 1: you can look at your baby picture and be like, oh,
32:10
Speaker 1: I can tell like you know, I'm drinking coffee as
32:12
Speaker 1: a two year old or whatever, or Orge has got
32:15
Speaker 1: a little banana his baby picture. Um, you can look
32:18
Speaker 1: back at this baby picture of the universe and and
32:20
Speaker 1: understand why our universe looks the way it does and
32:23
Speaker 1: gives us a huge amount of information about our universe today. Well,
32:27
Speaker 1: this is a perfect spot to take a break. We'll
32:29
Speaker 1: be right back. So how is that information coded. It's
32:45
Speaker 1: coded in the little differences. So if you look at
32:48
Speaker 1: the cosmic microwave background radiation maps, and if you're in
32:51
Speaker 1: front of a computer, you should google cosmic microwave background
32:54
Speaker 1: and you'll see this image. It's sort of like reds
32:56
Speaker 1: and blues and greens. And what you're seeing there is
32:59
Speaker 1: that is this slightly different energies you see if you
33:02
Speaker 1: look in different directions. So you get this radio wave
33:05
Speaker 1: it's microwave, and that has a certain frequency, and their
33:08
Speaker 1: frequency means a certain energy and there's very small variations. UM.
33:12
Speaker 1: And so what we do is we measure the energy
33:13
Speaker 1: in different directions and we see that in some places
33:16
Speaker 1: it's like one one hundred thousands hotter or one one
33:20
Speaker 1: thousands colder, and that's telling us something about the density
33:24
Speaker 1: of that plasma. Four hundred thousand years after the Big
33:27
Speaker 1: Bank fourteen, almost fourteen billion years ago telling us, oh
33:31
Speaker 1: this was a hot spot, this is a cold spot.
33:33
Speaker 1: And those are very small variations in sort of the
33:36
Speaker 1: temperature of the universe at that time. And you might think,
33:39
Speaker 1: well that why does that matter, alright, who cares about
33:42
Speaker 1: the tiny a little bit hotter, tined, a little bit colder. Well,
33:45
Speaker 1: those are the structures, the seeds of the structure of
33:48
Speaker 1: the universe itself. The universe has been totally smooth, like
33:52
Speaker 1: exactly homogeneous everywhere, and there's no way to sort of
33:55
Speaker 1: build anything because every particle is being pulled in every
33:58
Speaker 1: direction simultaneously. What you need to start the seed structure
34:02
Speaker 1: to get like galaxies and planets and stars and people
34:04
Speaker 1: and bananas and hamsters is you need a little bit
34:07
Speaker 1: of variation. And so these are the original seeds of
34:10
Speaker 1: variation that caused the structure that we see today. So
34:15
Speaker 1: if everything was all the same, maybe you're really boring here. Yeah,
34:20
Speaker 1: we wouldn't be here because that you would never form
34:22
Speaker 1: any structure. You would never form really hot, dense things
34:25
Speaker 1: like stars to give light and planets for people to
34:27
Speaker 1: live on. It would just be smooth and not very dense.
34:31
Speaker 1: So in order to get anything interesting in the universe.
34:33
Speaker 1: You need little packets of density to start off with.
34:35
Speaker 1: And if those packets were even slightly different, our universe
34:40
Speaker 1: would be so completely different we wouldn't even recognize it. Yeah,
34:43
Speaker 1: you wouldn't have a galaxy here, You might have a
34:44
Speaker 1: galaxy somewhere else, totally far away. Yeah. And the amazing
34:48
Speaker 1: thing is that these those variations are totally random. They
34:51
Speaker 1: come from quantum mechanics. Like, where do you get these
34:54
Speaker 1: variations from the beginning? The universe started out sort of symmetric,
34:58
Speaker 1: and how else could it start? Then? How you get
35:00
Speaker 1: any variation to see the structure comes from quantum mechanics.
35:03
Speaker 1: Quantum randomness strikes again. It keeps following me around. It's everywhere.
35:08
Speaker 1: So you get little random fluctuations. Those little fluctuations get
35:11
Speaker 1: expanded into bigger fluctuations, and then they become, you know,
35:14
Speaker 1: larger and larger. So we said, see these really really minor,
35:18
Speaker 1: very subtle fluctuations in this early plasma. You know that
35:21
Speaker 1: took fourteen billion years for gravity to build on and
35:24
Speaker 1: to make something big and beautiful and elaborate that we
35:27
Speaker 1: are living in today. So for scientists starts studying the
35:31
Speaker 1: cosmic microwave back on the c MB right now. Are
35:35
Speaker 1: they asking questions about the past or are they looking
35:40
Speaker 1: at either at present time or future time? Yeah, that well,
35:44
Speaker 1: that's a great question. I think people want to understand
35:47
Speaker 1: the past because they want to know the future. Like
35:49
Speaker 1: I'd like to know how long is the univer is
35:51
Speaker 1: gonna be around, is going to keep pairing itself apart
35:53
Speaker 1: or turn around and crunch? And part of answering the
35:56
Speaker 1: questions about the future means looking into the past and
35:58
Speaker 1: understanding the origins and revealing the mechanisms. So I think
36:02
Speaker 1: we're asking mostly asking questions about the past, but really
36:04
Speaker 1: because we want to know the answers about the future.
36:07
Speaker 1: And the CNB reveals all sorts of things like how
36:09
Speaker 1: much dark energy was there, how much dark matter was
36:11
Speaker 1: there in the very early universe, how much matter was
36:15
Speaker 1: there in general, All sorts of things are encoded in
36:18
Speaker 1: the details of the CNB, And that's the kind of
36:20
Speaker 1: thing that scientists are focusing on today's is pulling out
36:23
Speaker 1: as much information as possible from this early map of
36:25
Speaker 1: the universe. So this is just one of the many
36:29
Speaker 1: types of radiation that I can't see that's being like that.
36:34
Speaker 1: I'm basically swimming through as I go about my day.
36:38
Speaker 1: Imagine if we were all blind, humanity was all blind
36:41
Speaker 1: and nobody could see it would be difficult to imagine. Oh,
36:44
Speaker 1: there's all this information around us that we're not capturing,
36:46
Speaker 1: and the light would be there, but we just wouldn't
36:49
Speaker 1: be using it to understand our world. Well, that is
36:51
Speaker 1: our situation. We are all blind. We're blind to all
36:54
Speaker 1: these different other kinds of light and particle that are
36:56
Speaker 1: all around us with incredible information about the universe that
36:59
Speaker 1: we just can't see. In hill, we build telescopes and
37:02
Speaker 1: new devices that are sensitive to these kinds of radiation
37:04
Speaker 1: and these particles that can help us understand these clues.
37:08
Speaker 1: What's the most mind blowing thing about the CMB that
37:12
Speaker 1: you ever learned? And can you describe that moment? Yeah.
37:15
Speaker 1: The thing that I think is amazing about the CMB
37:18
Speaker 1: is that we can see sound in the CMB, Like, okay, wait,
37:23
Speaker 1: we can see sound. Yeah, we can see sound. So
37:25
Speaker 1: what is sound? Sound is waves? Sound is a like ripples.
37:30
Speaker 1: So for example, you're sitting your bathtub and you move
37:32
Speaker 1: your arm, you see waves in the water, right, So
37:35
Speaker 1: those are waves. Sound is just waves in air. So
37:38
Speaker 1: when we say, well, maybe instead of saying sound, I
37:40
Speaker 1: should have said we see ripples. We see waves in
37:43
Speaker 1: the CMB, we see ostillations because there's some kind of
37:46
Speaker 1: matter in the early universe, in the early plasma that
37:48
Speaker 1: can interact, like pulls itself together like normal matter, and
37:53
Speaker 1: some matter that doesn't, like dark matter, doesn't really feel anything,
37:56
Speaker 1: and so those different kinds of matter have different kinds
37:59
Speaker 1: of oscillles, like one grand one is pulling in one way,
38:02
Speaker 1: the other one is pushing the other way, because it interacts.
38:05
Speaker 1: And we can see patterns in the cosmic microwave background
38:08
Speaker 1: radiation that reflects the oscillations of the plasma, and those
38:12
Speaker 1: oscillations are sensitive to like how much matter was there
38:15
Speaker 1: that was interacting, how much matter was it that was
38:17
Speaker 1: not interacting, And that tells us how much dark matter
38:21
Speaker 1: there was a bit jillion years ago. And to me,
38:23
Speaker 1: like revealing that crazy, complicated, subtle fact about the early
38:28
Speaker 1: universe from looking at like the wiggles in this tiny
38:31
Speaker 1: little bit of light that nobody even knew about until
38:33
Speaker 1: fifty years ago. It blew my mind when I when
38:36
Speaker 1: I thought, like, wow, people are really dig in details
38:39
Speaker 1: out of this thing. Do you remember where you were
38:42
Speaker 1: or what you were doing when you had that thought.
38:44
Speaker 1: That was earlier this morning when I googled cosmic microwave
38:47
Speaker 1: background the agent no. UM. I came to astrophysics and
38:51
Speaker 1: cosmology sort of late because my background was more in
38:54
Speaker 1: particle physics and understanding, you know, the basic building structure
38:57
Speaker 1: and basic building blocks. But I was always interested in
38:59
Speaker 1: the universe, and so I did a little bit of
39:01
Speaker 1: self teaching after I got tenure, did a little bit
39:04
Speaker 1: more reading and try to understand this stuff. So about
39:06
Speaker 1: ten years ago, I think that I really started to
39:08
Speaker 1: try to wrap my mind around what is this stuff
39:10
Speaker 1: out there in the universe? What is uh? What are
39:12
Speaker 1: we learning about the origins of the universe from the
39:15
Speaker 1: light that we can see here on Earth. So you
39:17
Speaker 1: mentioned the CMB being able to give us clues about
39:20
Speaker 1: dark matter behavior. Is that sort of one of the
39:24
Speaker 1: new areas of research for the CMB, or you know,
39:30
Speaker 1: what what are the hot topics now? If there's a
39:32
Speaker 1: gold Russian data for you know, CMB related research, what
39:36
Speaker 1: questions should I be putting on my grant application? Yeah?
39:40
Speaker 1: That's great, Um. I think the most important question that
39:44
Speaker 1: the CMB can answer is sort of like the pie
39:46
Speaker 1: chart of the universe, like, what is most of the
39:48
Speaker 1: energy in the universe used for? And we know roughly
39:51
Speaker 1: the answer. It's five percent matter. Dark matter a huge
39:56
Speaker 1: chunk of his dark energy. And the cool thing is
39:58
Speaker 1: that we know that from you know, looking at matter
40:01
Speaker 1: and looking at stars and looking at galaxy and seeing
40:03
Speaker 1: the expansion of the universe. But the CMB gives is
40:05
Speaker 1: a totally independent way to measure those fractions because again
40:09
Speaker 1: sort of the oscillations in the plasma are sensitive to
40:11
Speaker 1: those fractions. So what people are doing now is trying
40:14
Speaker 1: to just get more precise measurements and asking does that
40:16
Speaker 1: agree with what we already think. And the way you
40:19
Speaker 1: get more precise measurements you just get more data because
40:21
Speaker 1: you're looking for really small variations. So we have these
40:24
Speaker 1: successive generations. First the telescope in the sixty four that
40:27
Speaker 1: just heard like, oh it's there. Then there was a
40:30
Speaker 1: satellite called Kobe in the nineties that found these variations.
40:33
Speaker 1: They were like, oh, look this interesting information. Then there
40:36
Speaker 1: was w MAP, which is a satellite saw even more details,
40:39
Speaker 1: and then recently the Plank experiment. And so if you
40:42
Speaker 1: look at the CNB over years, it's sort of like
40:44
Speaker 1: this blob that's becoming more and more and sharper and
40:46
Speaker 1: sharper focus and answering these questions in more detail, and
40:49
Speaker 1: recently we're sort of getting slightly different answers, like the
40:53
Speaker 1: CMB tells us this is this much dark energy in
40:55
Speaker 1: the universe, whereas other measurements tell us a slightly different answer.
40:58
Speaker 1: We don't know why those things don't agree. Is it
41:01
Speaker 1: because our model the universe is wrong or because one
41:04
Speaker 1: of these measurements is wrong? And so that's sort of
41:07
Speaker 1: the current puzzles, like how let's make these two kinds
41:10
Speaker 1: of measurements as precise as possible and see if they
41:12
Speaker 1: agree and if they don't, Oh, that's a fun clue
41:15
Speaker 1: because it tells us we're going to learn something. So
41:19
Speaker 1: how do I interact with the cosmic microwave background every day?
41:24
Speaker 1: Or do I is there any way for me to
41:26
Speaker 1: see it? Or is it a way for it to
41:28
Speaker 1: influence my life that I just might not be aware of. Well,
41:31
Speaker 1: because there are microwaves, they hit your body and they
41:34
Speaker 1: heat you up very slightly, right, it's not a huge
41:37
Speaker 1: amount of radiation, but you can see if you have
41:40
Speaker 1: one of those old television screens that a cathode ray tube,
41:43
Speaker 1: not like a flat panel display. Those things are sensitive
41:46
Speaker 1: to the microwave background, and part of the fuzz on
41:48
Speaker 1: those screens comes from this background radiation. Really, and the
41:52
Speaker 1: snow on those screens comes from this microwave background radiation.
41:55
Speaker 1: So you could literally see this evidence years and years
41:59
Speaker 1: and years ago. So I don't need a radio telescope,
42:01
Speaker 1: I just need an old TV and I can I
42:04
Speaker 1: can see it. That's right, you can see the secrets
42:06
Speaker 1: of the early universe. That's a really great TV show. Amazing. Yeah,
42:12
Speaker 1: And I think another thing that people are often confused
42:15
Speaker 1: by sort of again this like where was it? And
42:18
Speaker 1: I think the thing to remember is that it was everywhere.
42:20
Speaker 1: And so the CNB they were seeing in one direction
42:22
Speaker 1: was hot plasma that was in one place, and the
42:24
Speaker 1: stuff we're seeing another direction was hot plasma we're seeing
42:27
Speaker 1: from somewhere else. So I know in academia there's often
42:31
Speaker 1: multiple schools of thought about really important things, theories, hypotheses, etcetera.
42:36
Speaker 1: And it sounds like the detection of these radio waves
42:41
Speaker 1: this microwave um background helped to resolve one of those disagreements.
42:48
Speaker 1: Has it caused others do people not believe in it?
42:52
Speaker 1: Or are there heated debates happening in the whole hallowed
42:57
Speaker 1: halls of the Ivory Tower about the CMB. I think
43:01
Speaker 1: it's a sort of a process, like a lot of
43:03
Speaker 1: the old question has been put to rest. I don't
43:05
Speaker 1: think anybody seriously disagrees with the Big Bang theory anymore.
43:09
Speaker 1: But of course there are new questions, and some of
43:11
Speaker 1: those new questions are about like what do we see
43:13
Speaker 1: in the CMB. There are some weird things we don't understand,
43:16
Speaker 1: and those lead to like crazy ideas. For example, there's
43:20
Speaker 1: one spot in the CNB that's colder than all the
43:22
Speaker 1: other spots. It's called the cold spot. What a great name.
43:25
Speaker 1: And it's also kind of big. And you can say, well,
43:28
Speaker 1: you know, there's random fluctuations. You would expect, some cold
43:30
Speaker 1: and some hot, but this one is colder than you
43:32
Speaker 1: would expect and bigger than you expect. So it's it's
43:34
Speaker 1: kind of unusual. And anytime you see something a little
43:37
Speaker 1: out of the ordinary, you wonder, is that a clue
43:40
Speaker 1: or is that, you know, just random. And so people
43:43
Speaker 1: speculated things like maybe that cold spot is evidence that
43:47
Speaker 1: our universe when it was really young, bumped into another
43:50
Speaker 1: universe and left basically a bruise. I know that's hard
43:55
Speaker 1: to imagine, it's hard to even think about. But some
43:57
Speaker 1: people have this theory that there are multiple universes created
44:00
Speaker 1: one sort of in a multiverse theory, and if those
44:03
Speaker 1: universes were near enough each other, they could have interacted
44:06
Speaker 1: very early on, and they predict exactly this kind of
44:09
Speaker 1: signature in the CMB as evidence for that. Now is
44:13
Speaker 1: that a prediction or is this sort of a post addiction,
44:15
Speaker 1: Like Okay, I saw this weird thing and now I'm
44:18
Speaker 1: gonna try to explain it, and I get to make
44:20
Speaker 1: this crazy theory. I don't know, but that's the kind
44:22
Speaker 1: of thing people argue about. So still TBD, watch it,
44:27
Speaker 1: watch this space. That's right, there's a lot left to
44:29
Speaker 1: learn about the universe from the cosmic microwave background. How
44:32
Speaker 1: should I be thinking about this? Like when I'm having
44:34
Speaker 1: my you know, shower thoughts are so important. I think.
44:37
Speaker 1: You know, when you're idly at rest doing a mundane
44:41
Speaker 1: task that your brain doesn't have to think about, it
44:43
Speaker 1: wanders off and usually for me into like existential questions.
44:48
Speaker 1: That's when you think about physics. Physics, Yeah, more more philosophy. UM,
44:53
Speaker 1: you know those big questions like why why are we here?
44:57
Speaker 1: Is this seven am call I'm getting ready for? Really
45:00
Speaker 1: that important in the grand scheme of things, like on
45:03
Speaker 1: a universal time scale? You know, does anything matter? Should
45:07
Speaker 1: I just be watching a Netflix marathon all day to day?
45:10
Speaker 1: These types of things. So as I'm having those thoughts,
45:13
Speaker 1: deep deep thoughts, how should I be thinking about the
45:17
Speaker 1: cosmic microwave background? Is it um fossil as you said before,
45:21
Speaker 1: because that sounds very static, but it's something that's continuing
45:24
Speaker 1: to move and continuing to give information. Is it a
45:28
Speaker 1: comforting um wrap of radiation from the early universe that's
45:33
Speaker 1: giving me a hug? How should I? How should I
45:36
Speaker 1: think about this? UM? I think you should think about
45:39
Speaker 1: it aspirationally. You should wonder what else is out there?
45:43
Speaker 1: What other information is floating out there in space. It's
45:46
Speaker 1: going to give us some incredible deep knowledge about the universe.
45:49
Speaker 1: It's going to change the entire context of our lives.
45:53
Speaker 1: And we don't even know it exists yet, and then
45:55
Speaker 1: in a hundred years or fifty years or two years,
45:58
Speaker 1: somebody will discover it reveal something deep about the universe,
46:02
Speaker 1: and we will have not even known. Um, I like
46:04
Speaker 1: to look at the history of physics that way and
46:06
Speaker 1: be like people stumble across something and it changes the
46:09
Speaker 1: way we think about the universe. And I hope that
46:11
Speaker 1: there are so I said aspirationally, because I hope there
46:13
Speaker 1: are more of these. I hope there are more moments
46:15
Speaker 1: when we dig up something from the early universe and
46:18
Speaker 1: it teaches us something and maybe it's surprising, and people
46:21
Speaker 1: are trying to do that right now. The plasma from
46:23
Speaker 1: the early universe ended about four hundred thousand years after
46:27
Speaker 1: the Big Bang, and that this is the only light
46:29
Speaker 1: we can see because before that all the light was
46:31
Speaker 1: just reabsorbed by the plasma, so it's sort of gone.
46:34
Speaker 1: But people are trying to dig deeper, just saying, well,
46:36
Speaker 1: what about like neutrinos from before from inside of that plasma,
46:39
Speaker 1: because they don't interact very much, and maybe we could
46:41
Speaker 1: see them were gravitational waves from the very first moment.
46:44
Speaker 1: So we're trying to open up new kinds of eyes
46:47
Speaker 1: to see deeper and deeper into the history of the
46:48
Speaker 1: universe and answer our questions about that. So, um, yeah,
46:51
Speaker 1: I think about that. I think about what your children
46:53
Speaker 1: or their children will know about the universe that we
46:55
Speaker 1: can't even imagine. So I'm like, I'm in justest imagining
46:58
Speaker 1: the situation in which the people that ask questions and
47:02
Speaker 1: want to know things are kind of like this nerve center.
47:05
Speaker 1: And we have so many different senses like you and
47:07
Speaker 1: I would have site and and sound, but we have
47:10
Speaker 1: all of these different detectors that scientists have have developed
47:14
Speaker 1: as as part of their senses. And so what I'm
47:16
Speaker 1: hearing you say is that we're going to continue to
47:18
Speaker 1: develop more senses as we want to be able to
47:22
Speaker 1: detect the information around us. Is that accurate science is
47:25
Speaker 1: making esp real. We are developing new senses to experience
47:29
Speaker 1: the university you already here. First, guys, the universe was
47:33
Speaker 1: in a state in which this type of radiation wasn't
47:36
Speaker 1: able to escape, and then there was a cooling event
47:41
Speaker 1: in which, uh, the universe became transparent, allowing light to
47:46
Speaker 1: emanate through it. And this radiation is part of that
47:51
Speaker 1: early expansion, and it's coming from all of these different
47:56
Speaker 1: directions because we're expanding our idea of the Big Bang
47:59
Speaker 1: beyond the point theory um, and so it's radiating from
48:04
Speaker 1: everywhere because we are the center of the universe. Obviously
48:07
Speaker 1: we're humans. It's meeting here on Earth right where we
48:10
Speaker 1: are standing in the world and able to give us
48:13
Speaker 1: information about the past experiences that that it had and
48:17
Speaker 1: helping us understand the universe. That's right. But aliens somewhere else,
48:21
Speaker 1: they're also seeing a CMB. They see a slightly different
48:24
Speaker 1: map because the light that's getting to them left from
48:26
Speaker 1: a different place, but the same way, they see different
48:29
Speaker 1: stars in the sky than than we do. They're seeing
48:32
Speaker 1: a slightly different CNB, So everyone would see everyone, all
48:36
Speaker 1: of the different extraterrestrials in our universe is seeing a
48:39
Speaker 1: different one and studying it differently. And maybe one day
48:42
Speaker 1: we'll be able to put our data together and I
48:44
Speaker 1: get the most accurate picture of what started all of this.
48:49
Speaker 1: That's right, So I hope we do one day get
48:52
Speaker 1: to talk to alien physicists. I have a lot of
48:53
Speaker 1: questions for them about how the universe works and how
48:56
Speaker 1: they think about it, and whether we're UM studying objective
48:59
Speaker 1: truth or just based on our human bias and and
49:02
Speaker 1: uh on our senses. I think they probably have all
49:04
Speaker 1: sorts of other ways to observe the universe. We can't
49:06
Speaker 1: even imagine UM. But I hope that they're impressed with
49:09
Speaker 1: what we've accomplished and that we can learn from them. So,
49:12
Speaker 1: the universe began, and had it begun slightly differently, we
49:16
Speaker 1: wouldn't be here, but it developed the way that it did,
49:19
Speaker 1: and so we're able to ask questions about how it
49:22
Speaker 1: all started. That's right. So the amazing thing about the
49:25
Speaker 1: Cosmic Microwave Background Edition is that it's all around us
49:28
Speaker 1: and it gives us clues about the very beginning of
49:30
Speaker 1: the universe, and hopefully one day we'll find more clues
49:33
Speaker 1: and learn even more about the origins of our very existence.
49:37
Speaker 1: And it's heating me the way that I heat soup.
49:40
Speaker 1: That's my gutso made my big tang out for this.
49:43
Speaker 1: That's right. It's exciting you. It's exciting you the way
49:46
Speaker 1: you're microwave excitor soup. And I hope this podcast is
49:49
Speaker 1: excited our listeners. I hope so too. So thanks Crystal
49:52
Speaker 1: very much for joining me today. Oh thank you for
49:54
Speaker 1: having me. This was a great conversation. And for those
49:56
Speaker 1: of you out there, if you still have questions about
49:58
Speaker 1: this topic, send them to us to questions at Daniel
50:01
Speaker 1: and Jorge dot com. We really do answer all of
50:03
Speaker 1: our emails and thanks for tuning in. If you still
50:14
Speaker 1: have a question after listening to all these explanations, please
50:17
Speaker 1: drop us a line. We'd love to hear from you.
50:20
Speaker 1: You can find us at Facebook, Twitter, and Instagram at
50:23
Speaker 1: Daniel and Jorge That's One Word, or email us at
50:26
Speaker 1: Feedback at Daniel and Jorge dot com. Thanks for listening,
50:30
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50:33
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