Latest / Daniel and Kelly’s Extraordinary Universe / What can neutrinos teach us about supernovas?

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What can neutrinos teach us about supernovas? · Daniel and Kelly’s Extraordinary Universe

• 0:08
  Speaker 1: Or Hey, did you ever wish you had a different
• 0:11
  Speaker 1: kind of eyeball? Well, that's a weird question. I guess
• 0:16
  Speaker 1: I'm pretty happy with my eyeballs right now. I like,
• 0:18
  Speaker 1: I wouldn't want it to be cubic or you know,
• 0:20
  Speaker 1: any other shape rather than it's around. How about you?
• 0:23
  Speaker 1: I mean, my eyeballs are great, but there's just so
• 0:26
  Speaker 1: much that they miss them at the universe. You know,
• 0:28
  Speaker 1: they can't see infrared or ultra violet, or dark matter
• 0:32
  Speaker 1: or neutrinos or dark energy or all that great stuff.
• 0:35
  Speaker 1: But you can't see that you can, and you've been
• 0:38
  Speaker 1: holding out on us. Well, I guess I don't get it.
• 0:41
  Speaker 1: I mean, do you want your eyeballs to see more things?
• 0:43
  Speaker 1: Or do you want more eyeballs? Like, would you want
• 0:45
  Speaker 1: extra eyeballs for each of those types of light or things?
• 0:48
  Speaker 1: I wonder if I look more like a physics professor,
• 0:50
  Speaker 1: if I had four sets of eyeballs and even eat glasses,
• 0:55
  Speaker 1: you know, you would wouldn't just have four eyes, you
• 0:56
  Speaker 1: would have sixteen eyes, which would make me look like
• 0:58
  Speaker 1: four times as smart. Art. Well, it would definitely raise
• 1:01
  Speaker 1: your eye. Que Hi am r handmaker tennis and the
• 1:19
  Speaker 1: creator of PhD comics. Hi, I'm Daniel. I'm a particle
• 1:22
  Speaker 1: physicist and a professor at U C Irvine, and I
• 1:25
  Speaker 1: will always fund a grand proposal that tries to build
• 1:28
  Speaker 1: a new kind of eyeball. I thought you were gonna say,
• 1:32
  Speaker 1: you're gonna say you would find any proposal that makes
• 1:35
  Speaker 1: you want to have more eyes. Yeah, exactly, that's what
• 1:38
  Speaker 1: I mean. They don't have to be orbs implanted in
• 1:41
  Speaker 1: my physical wet wear. If we build a new kind
• 1:43
  Speaker 1: of technology that's sensitive to something new about the universe
• 1:46
  Speaker 1: and translates those signals into something we can understand, that's
• 1:50
  Speaker 1: kind of like an eyeball. Interesting. So if I sent
• 1:52
  Speaker 1: you an email proposing a seven billion dollar new kind
• 1:56
  Speaker 1: of eyeball, you would you would send me the money.
• 1:59
  Speaker 1: I will go to bout for you with the funding
• 2:00
  Speaker 1: agencies to fund that proposal, that they send it to
• 2:03
  Speaker 1: me for review, I will say fund fund fund No no, no.
• 2:07
  Speaker 1: That you said you would fund whatever proposal propos and
• 2:09
  Speaker 1: you kind of eyeball Yeah, absolutely, yeah. Please wait for
• 2:12
  Speaker 1: your check. Thanks. I look for it with my prototype eyeballs.
• 2:18
  Speaker 1: The Daniel Science Foundation might be in your junk mail folder.
• 2:21
  Speaker 1: Is that what the foundation does it just sends junk
• 2:23
  Speaker 1: mail encouraging people to make more eyeballs. Somebody's got to
• 2:28
  Speaker 1: do the hard work around here. But anyways, welcome to
• 2:30
  Speaker 1: our podcast. Daniel and Horror explain the universitate production of
• 2:33
  Speaker 1: My Heart Radio, in which we connect your eyeballs and
• 2:36
  Speaker 1: your earballs do all the interesting things going on out
• 2:39
  Speaker 1: there in the universe, the incredible cosmic rays streaking nearly
• 2:43
  Speaker 1: the speed of light through the universe, carrying with them
• 2:46
  Speaker 1: messages from the distant reaches of the cosmos, and bearing
• 2:50
  Speaker 1: secrets about strange physical processes. We try to digest all
• 2:54
  Speaker 1: of that information that's coming here to Earth and explain
• 2:57
  Speaker 1: all of it to you. Yeah, because it is a
• 3:00
  Speaker 1: pretty incredible universe full of things happening all the time,
• 3:03
  Speaker 1: every second of the day, every second of the night.
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  Speaker 1: There is something going on in the universe, and it's
• 3:07
  Speaker 1: screaming for us to learn and discover it. That's right,
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  Speaker 1: And almost everything out there in the universe produces some
• 3:14
  Speaker 1: kind of message. Is it a proton, is an electron?
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  Speaker 1: Is it a photon, Is it a neutrino? Is it
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  Speaker 1: dark matter? It always produces some kind of impact rippling
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  Speaker 1: through the universe. And if clever apes on this third
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  Speaker 1: planet from the Sun learned to listen to those messages,
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  Speaker 1: they might just deduce some secrets of the universe. Yeah,
• 3:32
  Speaker 1: because I think that's an interesting thing about the universe,
• 3:34
  Speaker 1: is that there's stuff happening all the time, and it
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  Speaker 1: all has an effect on the rest of the universe, right, Like,
• 3:39
  Speaker 1: almost nothing happens that it doesn't affect anything else. Energy
• 3:42
  Speaker 1: is always flashing back and forth. Stars shootout energy, which
• 3:46
  Speaker 1: gets absorbed by other stuff, which heats up, which radiates
• 3:48
  Speaker 1: out energy. They're all these flows in the universe of
• 3:52
  Speaker 1: energy being released and captured and re released, an incredible
• 3:55
  Speaker 1: cosmic swirl. Yeah, there's stuff happening, and it's it's shooting
• 3:58
  Speaker 1: out stuff all the time, and we and we are
• 4:00
  Speaker 1: literally kind of bathd in information about the universe. All
• 4:03
  Speaker 1: that stuff is coming to us, passing through us. And
• 4:05
  Speaker 1: if we can only learn to see it, or at
• 4:07
  Speaker 1: least hear it in the right way with our earballs,
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  Speaker 1: I guess we would learn a lot about the universe.
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  Speaker 1: I think a lot about how our mental picture of
• 4:15
  Speaker 1: reality is determined by the senses that we have. A
• 4:19
  Speaker 1: lot of people are very visual, and so their mental
• 4:21
  Speaker 1: picture of how the universe looks depends on what they
• 4:23
  Speaker 1: are seeing, and they imagine that what they see is
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  Speaker 1: what's there, and things they don't see aren't there. But
• 4:29
  Speaker 1: we know that there's a lot more going on in
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  Speaker 1: the universe, that there are plenty of things out there
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  Speaker 1: that we can't see with our eyeballs but are just
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  Speaker 1: as real as the things that we can see. What
• 4:40
  Speaker 1: if you're more sort of touch oriented, what kind of
• 4:43
  Speaker 1: picture of the universe would you feel? I wonder about that.
• 4:46
  Speaker 1: For people who can't see, for example, what kind of
• 4:48
  Speaker 1: mental model of the universe they have. They must still
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  Speaker 1: have some sort of three D model where they build
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  Speaker 1: up shapes based on sound and touch and all sorts
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  Speaker 1: of other clues. But I wonder if it's a very
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  Speaker 1: different experience on their I really know, well, it is
• 5:01
  Speaker 1: a pretty incredible and exciting and active universe, and with
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  Speaker 1: all sorts of things happening in it, and not more so,
• 5:08
  Speaker 1: are more fantastic or incredible than stars exploding or supernovas.
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  Speaker 1: It's one of the most dramatic and least well understood
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  Speaker 1: things that happened in the universe. At the end of
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  Speaker 1: the life cycle of a star, sometimes they just go kaboom,
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  Speaker 1: and they can shine briefly as bright or brighter than
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  Speaker 1: the entire galaxy that they are in. Yet it's one
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  Speaker 1: of the most explosive I guess events that can happen
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  Speaker 1: in the universe, and it's kind of hard to believe
• 5:34
  Speaker 1: that we don't know a lot about them. I mean,
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  Speaker 1: when they happen, they're pretty bright, right, we can see
• 5:38
  Speaker 1: them all the way across from the next galaxy. They're
• 5:40
  Speaker 1: so bright, and they're really unusually transient. Most of the
• 5:44
  Speaker 1: things in the night sky just sit there and burn
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  Speaker 1: and they're the same every day, every year. But supernova
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  Speaker 1: are short lived that I light up the sky briefly
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  Speaker 1: and then disappear. It's the kind of thing that's so
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  Speaker 1: dramatic that you can actually find records of it in
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  Speaker 1: ancient history. People like hundreds are even up to US
• 6:00
  Speaker 1: thousand years ago writing stories about these strange things that
• 6:03
  Speaker 1: appeared in the night sky. Wow. Can you imagine being
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  Speaker 1: born at the time and looking up and then suddenly
• 6:09
  Speaker 1: this star starts burning super bright? What would you think
• 6:12
  Speaker 1: is going on? Would you freak out? It's hard to
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  Speaker 1: imagine it because it's hard to put yourself in the
• 6:16
  Speaker 1: place of somebody who has no idea what the sky means, right,
• 6:19
  Speaker 1: They don't even know what a star was. I had
• 6:22
  Speaker 1: that same experience when I saw the eclipse birthand in
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  Speaker 1: the path of totality. It was really an incredible experience,
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  Speaker 1: and it made me wonder what it must have been
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  Speaker 1: like twenty thousand years ago for stone age man to
• 6:34
  Speaker 1: look up and see this thing happening, and I thought
• 6:36
  Speaker 1: the world was ending. Clearly something important was going on
• 6:40
  Speaker 1: right right right, Or maybe they just thought that like, oh,
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  Speaker 1: look it's Zeus, or look it's mercury taking off its start. Yeah,
• 6:48
  Speaker 1: or somebody out there knows what I did, right, Every
• 6:51
  Speaker 1: guilty person on the planet was like, oh, I've been caught.
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  Speaker 1: This is my fault. It's shining a spotline exactly. And
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  Speaker 1: so in the same way, if you look the nights guy,
• 7:00
  Speaker 1: you see a supernova, what do you think? It depends
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  Speaker 1: on what you think a star is. And those folks
• 7:05
  Speaker 1: are so ignorant they had no idea what they were
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  Speaker 1: looking at, And of course that makes me project forward.
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  Speaker 1: You know, what weird things are we seeing in the
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  Speaker 1: sky that we just don't really understand at all. And
• 7:15
  Speaker 1: in a thousand years, people will look back and be like, wow,
• 7:18
  Speaker 1: Daniel was so clueless. He had no idea what he
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  Speaker 1: was looking at. Like yeah, Like if you extrapolate the
• 7:23
  Speaker 1: progress of science since human knowledge into the future, like
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  Speaker 1: who knows what we're going to know in the future, right,
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  Speaker 1: maybe everything? Yeah, And who knows what ideas we have
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  Speaker 1: today that we take for granted will be overturned by
• 7:34
  Speaker 1: some crazy discovery. Maybe in ten years, maybe in a
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  Speaker 1: hundred years, our entire picture of the cosmos could be
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  Speaker 1: totally upended. Are you gonna be able like one of
• 7:42
  Speaker 1: those science fiction movies where you go like, oh, in
• 7:45
  Speaker 1: fifteen years, we'll be riding around in flying cars and
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  Speaker 1: know the secrets of the universe. And then fifteen years
• 7:50
  Speaker 1: go by and nothing has happened. I hope not. But
• 7:54
  Speaker 1: you know, it is research, and so it's hard to predict.
• 7:57
  Speaker 1: It doesn't really align with quarterly reports and predictions and
• 8:00
  Speaker 1: this kind of stuff. You just never know. The frustrating
• 8:03
  Speaker 1: thing about research, and this is what my grad students
• 8:06
  Speaker 1: have to learn, is that time spent is not equal
• 8:08
  Speaker 1: to progress made. Right, You can be busy, busy, busy, busy,
• 8:11
  Speaker 1: and get nowhere and then one afternoon, boom, it all
• 8:14
  Speaker 1: clicks together, and that's why research is not for everybody. Yeah,
• 8:19
  Speaker 1: I guess past performance is no indication of future returns, right,
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  Speaker 1: definitely not, definitely not. But the exciting thing about astrophysics
• 8:26
  Speaker 1: and cosmology is that we do know that we know
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  Speaker 1: very little about the universe. We know that most of
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  Speaker 1: the things going on out there are things we don't understand,
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  Speaker 1: which gives us you no hope that we will figure
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  Speaker 1: something out. At least there is something out there to learn,
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  Speaker 1: even if we're not quite sure exactly the way to
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  Speaker 1: unravel the mystery. Yeah, And so it's interesting that we
• 8:44
  Speaker 1: don't know a lot about its supernova. It's a kind
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  Speaker 1: of a big explosion, but it's it's there's still a
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  Speaker 1: lot that we don't know about them, and it might
• 8:51
  Speaker 1: be because maybe we're not looking at them in the
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  Speaker 1: right way. Yeah, the way that we look at the
• 8:55
  Speaker 1: universe with eyes and ears and touch and telescopes to
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  Speaker 1: see mostly pote Hans, it's just one slice of the universe,
• 9:02
  Speaker 1: and if you look at it in other ways, you
• 9:04
  Speaker 1: see a totally different universe. Yeah. But just to make
• 9:07
  Speaker 1: sure we haven't touched any supernose happening, there's a big
• 9:10
  Speaker 1: sign on it says do not touch, and I always
• 9:13
  Speaker 1: try to follow the rules. You're kind of pedantic in
• 9:17
  Speaker 1: that way, Yeah, exactly. But you know, depending on the
• 9:21
  Speaker 1: eyeball you use to look at the universe, even when
• 9:23
  Speaker 1: it comes to photons, if you look in the infrared
• 9:25
  Speaker 1: or the ultra violet or the visible light, you see
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  Speaker 1: a very different kind of universe because the different processes.
• 9:30
  Speaker 1: The stuff you were talking about earlier, the stuff that's
• 9:32
  Speaker 1: always going on in the universe, shines in different kinds
• 9:35
  Speaker 1: of light. But going beyond that, stuff in the universe
• 9:38
  Speaker 1: can shine in things that are not even light. Yeah,
• 9:40
  Speaker 1: And so supernova do that. They produce not just visible light,
• 9:44
  Speaker 1: but all kinds of light and all kinds of particles
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  Speaker 1: that might be able to tell us what's going on
• 9:49
  Speaker 1: during those crazy events. And so today on the podcast,
• 9:52
  Speaker 1: we'll be asking the question what can nutrinos ellas about
• 10:00
  Speaker 1: super novas? And how do we get a neutrino to
• 10:03
  Speaker 1: appear on the program to answer these questions? Would you
• 10:07
  Speaker 1: have any opinions or would you be neutral about everything?
• 10:10
  Speaker 1: They're so weak? Oh boy, that is a deep physics
• 10:16
  Speaker 1: joke right there. We won't even bother explaining it until later,
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  Speaker 1: But I had a more basic question, Daniels, it's supernovas
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  Speaker 1: or super nova? I think those who have learned Latin
• 10:26
  Speaker 1: will write in and say it's super nova with an
• 10:29
  Speaker 1: a E at the end. But I'm pretty sure I
• 10:31
  Speaker 1: hear physicists say supernovas all the time. I'm not sure
• 10:35
  Speaker 1: it's a good idea to correct them. Why not? Physicists
• 10:39
  Speaker 1: don't like to be corrected. So what you're saying not
• 10:42
  Speaker 1: on the pedantic actually it's pronounced supernovae doesn't meanly go
• 10:46
  Speaker 1: over very well in a seminar. Well. I've recently discovered that,
• 10:52
  Speaker 1: you know, fungas, you can say fun guy, or you
• 10:54
  Speaker 1: can just say funguses. Fungus is that is a terrible
• 10:57
  Speaker 1: sounding word. Yeah, it's optional in the English language at least,
• 11:01
  Speaker 1: But fun guy is so much funner because it sounds
• 11:03
  Speaker 1: like you're a fun guy. I know, right, But you know,
• 11:07
  Speaker 1: but if your name is Gus, then it's also good
• 11:09
  Speaker 1: to be one of the fun Gusses. I see. I
• 11:11
  Speaker 1: guess that could be the name of a band made
• 11:13
  Speaker 1: all of gusses, right, ten fun Gusses, the Fuses. I'm
• 11:17
  Speaker 1: sure that they'll sell out in no time. I'm sure
• 11:19
  Speaker 1: they'll be opening for the Grateful Dads sometime soon. Oh hey,
• 11:23
  Speaker 1: they're probably better anyways, so we might be the opening act.
• 11:28
  Speaker 1: But anyways, it is kind of interesting to think that
• 11:30
  Speaker 1: a supernova not just produces visible light in a big
• 11:33
  Speaker 1: flash that we can see with our eyes, but it
• 11:35
  Speaker 1: also produces a whole bunch of other things that maybe
• 11:38
  Speaker 1: we can use to learn what's inside of him. And
• 11:41
  Speaker 1: so Daniel went out there into the wilds of the
• 11:42
  Speaker 1: internet to ask listeners what do neutrinas teach us about supernova?
• 11:48
  Speaker 1: Thank you very much to everybody who volunteered, and if
• 11:51
  Speaker 1: you are a listener who has never participated, please write
• 11:54
  Speaker 1: to us two questions at Daniel and Jorge dot com.
• 11:57
  Speaker 1: We would love to have your voice on the podcast.
• 12:00
  Speaker 1: Think about it for a second. What do you think
• 12:01
  Speaker 1: we can learn about supernova from neutrinos. Here's what people
• 12:06
  Speaker 1: had to say. I remember seeing a documentary or something
• 12:08
  Speaker 1: a few years back about using trinos to see on
• 12:12
  Speaker 1: the to see what goes on on the inside of
• 12:14
  Speaker 1: stars image And when a supernova explodes, it puts out
• 12:18
  Speaker 1: just massive amounts of neutrinos and they sail through everything.
• 12:22
  Speaker 1: So if we could detect them and read their states.
• 12:25
  Speaker 1: That probably give us a lot of really good information
• 12:27
  Speaker 1: about what's going on inside of a supernova. I guess
• 12:30
  Speaker 1: they'd tell us the direction of the supernova because they
• 12:33
  Speaker 1: both fly through anything in spice and arrive at protector,
• 12:38
  Speaker 1: and they would car light in an energy sense with
• 12:42
  Speaker 1: the size of the bluff in some way. Putrinos probably
• 12:47
  Speaker 1: come in slightly different frequencies and different energy levels, different
• 12:53
  Speaker 1: so other qualities perhaps, and depending on exactly the type
• 12:57
  Speaker 1: of supernova that occurs, perhaps the new trino's can give
• 13:01
  Speaker 1: us a bit of information about how big these star
• 13:03
  Speaker 1: wars that exploded, or if it was a particular type
• 13:06
  Speaker 1: of explosion. I imagine they can probably give us quite
• 13:09
  Speaker 1: a bit of information. Maybe they tell us what kind
• 13:12
  Speaker 1: of nuclear reactions have occurred during this explosion, which would
• 13:19
  Speaker 1: tell us the composition and size of the star. From
• 13:25
  Speaker 1: what I know, the no can tell us what happened
• 13:29
  Speaker 1: after the supernova, if we have a neutron star, if
• 13:34
  Speaker 1: we have a black hole. Probably, but for sure I
• 13:40
  Speaker 1: know that it can tell us if we have a
• 13:44
  Speaker 1: neutron star after a supernova. So what I know about
• 13:48
  Speaker 1: supernova first of all is that they're basically a star
• 13:52
  Speaker 1: that exploded, and it sends off thousands of solar masses
• 13:57
  Speaker 1: of particles and material, and it also sends out a
• 14:03
  Speaker 1: lot of energy, like a lot of energy. And what
• 14:06
  Speaker 1: I'm imagining is since neutrinos are so incredibly small and
• 14:10
  Speaker 1: they could go and travel through even all of Earth
• 14:13
  Speaker 1: without even hitting a single atom and Earth, then that
• 14:17
  Speaker 1: means they're moving incredibly fast and there's a lot of them.
• 14:21
  Speaker 1: So if neutrinos, which we know quite a bit about
• 14:24
  Speaker 1: and how they're given off from certain particles, reach us
• 14:27
  Speaker 1: from supernova, I guess it could tell us what was
• 14:31
  Speaker 1: in that star and what that explosion was. Like, these
• 14:34
  Speaker 1: are some amazing answers. Yeah, they're pretty specific and pretty
• 14:39
  Speaker 1: um physics sounding to meaning I mean like did they
• 14:43
  Speaker 1: actually like give you a good ideas there? They're not
• 14:45
  Speaker 1: just physics sounding their physics containing. I mean, these are
• 14:48
  Speaker 1: really insightful answers. After I got these, I thought, Wow,
• 14:51
  Speaker 1: did I accidentally email like a neutrino physics conference, Like
• 14:54
  Speaker 1: these folks know what they're talking about? Wow? Cool? And
• 14:57
  Speaker 1: then you wrote down the ideas and you're going to
• 15:00
  Speaker 1: use them for research and not credit that. That's right.
• 15:02
  Speaker 1: I got seven billion dollars neutrino telescope funded based on
• 15:05
  Speaker 1: these ideas. Good is it all because of my letter
• 15:09
  Speaker 1: that I sent you? That's right, I want to cut them.
• 15:11
  Speaker 1: I'm still waiting for the first check from the Daniel
• 15:13
  Speaker 1: Science Foundation hasn't arrived. Yeah, and got a junk mail
• 15:17
  Speaker 1: from yourself, he said, so, but it's so easy. I
• 15:22
  Speaker 1: have very serious doubts about this foundation. Now you can't
• 15:24
  Speaker 1: even send itself its own junk mail. I'm starting to
• 15:27
  Speaker 1: get the same feeling. But anyways, supernova are pretty incredible events,
• 15:31
  Speaker 1: and so maybe let's just take it back to the
• 15:33
  Speaker 1: basic level and it's still our listeners. What a supernova is.
• 15:37
  Speaker 1: Supernova is an exciting moment in the life cycle of
• 15:39
  Speaker 1: a star. It's a huge explosion that blows out most
• 15:42
  Speaker 1: of the matter and releases an enormous amount of energy
• 15:45
  Speaker 1: that was stored in the star. And depending on the
• 15:48
  Speaker 1: kind of star that you have that you start with,
• 15:50
  Speaker 1: you can get supernova's in two basic ways. One is
• 15:54
  Speaker 1: you can just have like a really big star, and
• 15:57
  Speaker 1: remember that what happens at the heart of stars because
• 15:59
  Speaker 1: of incredible gravitational pressure and high temperatures, is that you're
• 16:03
  Speaker 1: fusing lighter elements into heavier elements. At some point, those
• 16:07
  Speaker 1: elements get so heavy that when you fuse them, you
• 16:10
  Speaker 1: don't get energy. You lose energy, and the heart of
• 16:13
  Speaker 1: the star starts to cool and can no longer support
• 16:15
  Speaker 1: itself against gravity, and then it collapses and you get
• 16:18
  Speaker 1: this huge supernova that's called a core collapse supernova. And
• 16:23
  Speaker 1: there's another kind where it doesn't quite have enough mass
• 16:27
  Speaker 1: in order to have a core collapse supernova. It sits
• 16:29
  Speaker 1: there as a white dwarf for a little while, and
• 16:31
  Speaker 1: then somebody comes along and gives it some extra fuel
• 16:34
  Speaker 1: triggers the supernova, and then it collapses. And so you
• 16:37
  Speaker 1: get this gravitational collapse towards the heart of the star,
• 16:40
  Speaker 1: which creates this incredible high temperature and pressure situation and boom,
• 16:45
  Speaker 1: all the fuel very quickly undergoes fusion, and you get
• 16:48
  Speaker 1: an incredible explosion of all that energy in a very
• 16:52
  Speaker 1: very short amount of time. Yeah, but I guess, just
• 16:55
  Speaker 1: to be clear, not every star goes supernova, right, Like,
• 16:57
  Speaker 1: it's actually kind of a rare thing for us are
• 17:00
  Speaker 1: to explode, that's right. It doesn't happen very often. If
• 17:02
  Speaker 1: you have a galaxy of about a hundred billion stars,
• 17:05
  Speaker 1: you'll only get about one to three supernova's per century,
• 17:09
  Speaker 1: so it's an unusual outcome. A lot more often, for example,
• 17:12
  Speaker 1: a red dwarf will just turn into a white dwarf
• 17:15
  Speaker 1: and not go supernova, or like, our son is not
• 17:17
  Speaker 1: gonna explode, it's just gonna kind of puff up and
• 17:19
  Speaker 1: then kind of go out, and just similar for forever.
• 17:23
  Speaker 1: You know, our star's endpoint is likely to be a
• 17:25
  Speaker 1: white dwarf, which is just hot lump of metal, you
• 17:28
  Speaker 1: know it just like with a core collapse supernova. It's burned,
• 17:31
  Speaker 1: it's fused, and then the byproducts of that fusion are
• 17:34
  Speaker 1: things it can no longer burn, and then eventually it
• 17:36
  Speaker 1: just goes out. By going out, we mean it's no
• 17:39
  Speaker 1: more fusion. It's still like a big hot lump. And
• 17:42
  Speaker 1: that's what a white dwarf is, is just like a
• 17:44
  Speaker 1: big glowing blob of fusion remnants which can no longer
• 17:48
  Speaker 1: burn anymore, but it sits there glowing for like a
• 17:51
  Speaker 1: trillion years until eventually becomes a black dwarf. Right, our
• 17:54
  Speaker 1: son has headed to be a hot mess, just like
• 17:56
  Speaker 1: most stars here on Earth as well. That's right, you're
• 17:59
  Speaker 1: turn that your career can end without a huge explosion
• 18:02
  Speaker 1: and just sort of fezzle out. Yeah, I thank you hopefully.
• 18:07
  Speaker 1: You know, I always hope for an uninteresting life, right.
• 18:09
  Speaker 1: Something I think is super interesting is that it's very
• 18:12
  Speaker 1: hard for us to predict when a star will go supernova.
• 18:15
  Speaker 1: So it's the kind of thing we usually just see afterwards.
• 18:17
  Speaker 1: It's not like we can say, oh, that star over
• 18:20
  Speaker 1: there is going to go supernova in seventeen days, let's
• 18:22
  Speaker 1: all point our telescopes at it. It's the kind of
• 18:24
  Speaker 1: thing we're like, whoa, look at that star. It just
• 18:26
  Speaker 1: went supernova. Quick point your telescope so we can catch
• 18:29
  Speaker 1: the last bits of it. Right. It's kind of unpredictable
• 18:31
  Speaker 1: when it happens, but it's it's not like it's random either, right,
• 18:35
  Speaker 1: Like it only happens in certain kinds of stars. Like
• 18:38
  Speaker 1: if you can something see a star and no, oh
• 18:39
  Speaker 1: that one's not gonna go supernova, or you can see
• 18:41
  Speaker 1: another star and say, oh that one can and might
• 18:44
  Speaker 1: one day go supernova. Yeah, but of the hundred billion stars,
• 18:48
  Speaker 1: it's not easy to predict which one is going to
• 18:50
  Speaker 1: go supernova. Part of that is because we don't understand
• 18:52
  Speaker 1: the life cycle of stars. Well enough to know like
• 18:55
  Speaker 1: which ones are going to go supernova, and it's not
• 18:58
  Speaker 1: easy to predict when they're going to go super nova.
• 19:00
  Speaker 1: So even if you're pretty sure that this star is
• 19:02
  Speaker 1: big enough and it's eventually going to go supernova, knowing
• 19:04
  Speaker 1: when that's going to happen is hard to predict. And
• 19:07
  Speaker 1: that's because we don't have a grasp on a lot
• 19:10
  Speaker 1: of the complex physics, and it depends a lot on
• 19:12
  Speaker 1: these physics. It's like predicting a hurricane. You know, can
• 19:15
  Speaker 1: you predict the path of a hurricane. There's no like
• 19:18
  Speaker 1: weird new quantum physics going on. It's just a lot
• 19:21
  Speaker 1: of calculations and the result is very sensitive to the details.
• 19:24
  Speaker 1: In the same way like can you predict when a
• 19:26
  Speaker 1: star is going to collapse? It depends on so much
• 19:29
  Speaker 1: crazy nuclear physics and really high density, high temperature situations
• 19:33
  Speaker 1: that we just can't describe yet, but I guess you can.
• 19:36
  Speaker 1: What I'm saying is you can sort of rule out
• 19:37
  Speaker 1: whole categories of stars from going supernova, and so there
• 19:40
  Speaker 1: is a certain category of stars that can go supernova.
• 19:43
  Speaker 1: That's true, although even the ones that you think can't
• 19:46
  Speaker 1: go supernova, like our son could eventually go supernova, Like
• 19:49
  Speaker 1: our son is gonna be a white dwarf if it
• 19:51
  Speaker 1: later acquired a binary star partner, like some other star
• 19:55
  Speaker 1: came nearby and they're orbiting near each other, and our son,
• 19:57
  Speaker 1: the white dwarf, stole a bunch of gas from this
• 20:00
  Speaker 1: new partner. It could then become a Type one A supernova.
• 20:03
  Speaker 1: So sometimes it's like this ramp them back to supernovas,
• 20:06
  Speaker 1: which is pretty hard to predict, but those are extraordinary events,
• 20:10
  Speaker 1: Like you need a whole another star to be to
• 20:11
  Speaker 1: come to our solar system. Yeah, that's true, you need
• 20:14
  Speaker 1: a whole of the star. Remember though, that a lot
• 20:15
  Speaker 1: of stars out there are in binary systems, and so
• 20:19
  Speaker 1: there's a lot of white dwarfs out there that could
• 20:21
  Speaker 1: potentially go Type one A supernova. I think it's super
• 20:24
  Speaker 1: cool because we have never seen the progenitor of a
• 20:27
  Speaker 1: supernova like we've seen them after the fact. We've never
• 20:30
  Speaker 1: had like a zoomed in, close up study of a
• 20:32
  Speaker 1: star just before it goes supernova because we've never been
• 20:35
  Speaker 1: able to predict when it was going to happen. M M,
• 20:38
  Speaker 1: I see interesting, all right, Well, just because they're rare
• 20:41
  Speaker 1: doesn't mean they're not cool. In fact, that just makes
• 20:43
  Speaker 1: them more special, right, and harder to to spot and
• 20:46
  Speaker 1: to study them. And these extreme events are sort of
• 20:48
  Speaker 1: the perfect laboratory for understanding what's going on inside the star,
• 20:51
  Speaker 1: Like how do you trigger a collapse? When does the collapse?
• 20:54
  Speaker 1: What's going on in the collapse? Can you understand how
• 20:57
  Speaker 1: our shock wave of propagates through this crazy material? What
• 21:00
  Speaker 1: we're interested in understanding is like what happens when all
• 21:03
  Speaker 1: these forces are at play, Like inside a supernova you
• 21:06
  Speaker 1: have gravity, you have the strong force from the quirks,
• 21:09
  Speaker 1: you have the weak force producing neutrinos. You have electromagnetism
• 21:13
  Speaker 1: because everything's charged, so you have all the forces sort
• 21:15
  Speaker 1: of at play at the same time. It's a great
• 21:17
  Speaker 1: opportunity to understand those things or to probe those things
• 21:20
  Speaker 1: if you can get enough data, if you can say,
• 21:22
  Speaker 1: like what's going on inside the star? That's why it's
• 21:25
  Speaker 1: a very exciting thing to study. Yeah, it's always a surprise,
• 21:28
  Speaker 1: I guess, I mean, is he kid? And you never
• 21:30
  Speaker 1: know when they're gonna happen. All right, let's dig into
• 21:32
  Speaker 1: a little bit more into supernova and how many we've
• 21:35
  Speaker 1: seen over the course of human history, and then let's
• 21:37
  Speaker 1: talk about what neutrinos can tell us about them. But
• 21:40
  Speaker 1: first let's take a quick break. All right, we're talking
• 21:55
  Speaker 1: about the neutrinos that come from a supernova and what
• 21:58
  Speaker 1: they could tell us about what a supernova is all about,
• 22:02
  Speaker 1: because they're surprising events in the universe and we've never
• 22:05
  Speaker 1: actually seen one, I guess close up or in slow
• 22:08
  Speaker 1: motion because they just happened, like trying to catch a
• 22:11
  Speaker 1: close up film of a popcorn popping kind of you
• 22:15
  Speaker 1: never know which which colonel is gonna pop exactly after
• 22:18
  Speaker 1: it pops, you can then point your camera at it,
• 22:19
  Speaker 1: right or yes. And one of the issues is that
• 22:23
  Speaker 1: supernova are so rare that they don't happen very close
• 22:26
  Speaker 1: to us very often. It's also good news because if
• 22:28
  Speaker 1: a supernova went off, you wouldn't be hearing this podcast.
• 22:33
  Speaker 1: You know, we'd be fry. Yeah, you don't want to
• 22:35
  Speaker 1: too close up of a supernova, right, It would be
• 22:38
  Speaker 1: the last thing you see exactly, which means that if
• 22:42
  Speaker 1: you want a close up view of a star that's
• 22:44
  Speaker 1: about to go supernova, you have to focus one of
• 22:47
  Speaker 1: our space telescopes at it, and they can only look
• 22:49
  Speaker 1: really really deep at a very small patch of the sky,
• 22:53
  Speaker 1: and so you basically have to know where to look
• 22:55
  Speaker 1: or build like zillions more space telescopes to look at
• 22:58
  Speaker 1: the whole sky simultaneous, which, of course you know the
• 23:01
  Speaker 1: Daniel Science Foundation would be very excited to fund. Well,
• 23:05
  Speaker 1: you really tuned this foundation. But do you admit it's
• 23:08
  Speaker 1: all a scamp. So I'm not sure what it's just
• 23:10
  Speaker 1: my fantasy foundation. You know, maybe some billionaire who's listening
• 23:13
  Speaker 1: will think that guy really knows how to do science.
• 23:15
  Speaker 1: I'm going to write him a check for fifty billion dollars.
• 23:18
  Speaker 1: Maybe that guy really clearly knows how to run a foundation.
• 23:21
  Speaker 1: I'll put him in charge. Exactly. This guy is confidence inducing.
• 23:25
  Speaker 1: Let me just write him a check. I see most
• 23:28
  Speaker 1: people play fantasy football, but physicists play fantasy foundation. Is
• 23:31
  Speaker 1: that what it is? What you're saying. So you get together,
• 23:35
  Speaker 1: you you make imaginary bets and on what science is
• 23:37
  Speaker 1: going to get funded? Yeah, but you know, the most
• 23:39
  Speaker 1: tantalizing and frustrating part of that is, while you might
• 23:42
  Speaker 1: never be a pro athlete, like you fantasize all of
• 23:45
  Speaker 1: these dreams about understanding the universe are really attainable, Like
• 23:49
  Speaker 1: Jeff Bezos really could buy us knowledge about the universe.
• 23:54
  Speaker 1: The only thing standing between us and understanding so many
• 23:56
  Speaker 1: things about the universe is a couple of dudes, right,
• 24:00
  Speaker 1: a couple of big checks. We know what to do,
• 24:02
  Speaker 1: we know how to do it, we just need the cash.
• 24:04
  Speaker 1: So it's frustrating to me that these fantasies are actually attainable. Well,
• 24:08
  Speaker 1: I'm confused, Daniel. Earlier you were saying that you can't
• 24:11
  Speaker 1: promise that you're going to get results with research, that
• 24:15
  Speaker 1: time doesn't equal results, But now you're saying money does
• 24:17
  Speaker 1: equal results. Or is that is that just what the
• 24:20
  Speaker 1: foundation says. Let's do the experiment and find out, you know,
• 24:22
  Speaker 1: send me the money. We'll see. Now, it's true that
• 24:26
  Speaker 1: you can't promise anything, and we could build like a
• 24:29
  Speaker 1: hundred new hubbles and seeing nothing interesting. But every time
• 24:33
  Speaker 1: we look out into the universe, we always find something
• 24:35
  Speaker 1: weird and surprising and bonkers that up ends our ideas.
• 24:39
  Speaker 1: And so I'm pretty confident that continued research will reveal something.
• 24:43
  Speaker 1: But yes, I won't make any actual promises any you
• 24:46
  Speaker 1: won't sign any legal contract now, but I'm all forced
• 24:49
  Speaker 1: off of funding science for sure, and it teaches incredible
• 24:52
  Speaker 1: things like the about supernovas, which is kind of interesting
• 24:56
  Speaker 1: to think that most are all supernovs really come from
• 24:58
  Speaker 1: a collapse, you know, like we tend to think of
• 25:01
  Speaker 1: explosions that's just things that react and then spew out
• 25:04
  Speaker 1: a bunch of energy. But actually all supernovaus, all right,
• 25:07
  Speaker 1: start off as as collapsing stars. The collapse, and the
• 25:09
  Speaker 1: key thing to understand there is that what happens inside
• 25:12
  Speaker 1: of the star depends on the temperature and the pressure,
• 25:16
  Speaker 1: like can you fuse hydrogen or can you fuse all
• 25:18
  Speaker 1: the way up to carbon or even further up the
• 25:21
  Speaker 1: periodic table. It just depends on the pressure and the temperature.
• 25:25
  Speaker 1: So the higher the temperature, the higher the pressure conditions
• 25:28
  Speaker 1: that you create, the more crazy things that could happen
• 25:30
  Speaker 1: inside that star. And so typically sort of steady state,
• 25:34
  Speaker 1: but as supernova, as you say, starts with the collapse,
• 25:36
  Speaker 1: which creates this incredible high temperature and high pressure inside
• 25:40
  Speaker 1: the star, and you can like burn a huge fraction
• 25:43
  Speaker 1: of the fuel inside the star in just seconds instead
• 25:46
  Speaker 1: of millions or billions of years. And that's why they're
• 25:49
  Speaker 1: so luminous, right, because that's kind of what's going on.
• 25:51
  Speaker 1: It's like in this when the star is just burning.
• 25:54
  Speaker 1: It doesn't have enough pressure and deeed to to fuse
• 25:58
  Speaker 1: some of the heavier elements. But when collapses, then you
• 26:01
  Speaker 1: have those conditions and then it all happens at the
• 26:03
  Speaker 1: same time, like in the type one a supernova. Typically
• 26:06
  Speaker 1: these are blobs made of carbon and oxygen, and they're
• 26:09
  Speaker 1: not hot enough to fuse carbon. But as soon as
• 26:11
  Speaker 1: they get over the tipping point, they get it just
• 26:13
  Speaker 1: enough gravity, it collapses and then all of a sudden,
• 26:16
  Speaker 1: boom fuses like a huge fraction, like a half or
• 26:19
  Speaker 1: a third of that carbon in a very brief amount
• 26:21
  Speaker 1: of time. And that's basically an explosion. Right. The difference
• 26:24
  Speaker 1: between a nuclear reactor and a nuclear bomb is whether
• 26:27
  Speaker 1: it's like a chain reaction and runaway explosion. And that's
• 26:30
  Speaker 1: what happens at the heart of a supernova when you
• 26:33
  Speaker 1: create conditions from the collapse, So you got to collapse
• 26:35
  Speaker 1: inwards and then a shock wave outwards. Yeah, it's like
• 26:38
  Speaker 1: a bounce, almost like a super bounce. It's a super bounce.
• 26:43
  Speaker 1: And people who do modeling of this stuff they try
• 26:45
  Speaker 1: to understand exactly what is happening. It's really complicated physics.
• 26:49
  Speaker 1: You know, are the photons getting absorbed by the iron.
• 26:51
  Speaker 1: Is it breaking up the iron which is causing this?
• 26:53
  Speaker 1: You know, whenever we do physics modeling, we can never
• 26:56
  Speaker 1: describe everything that's going on. It's just too many crazy details.
• 27:00
  Speaker 1: We always have to make judicious choices, like we think
• 27:02
  Speaker 1: it's a combination of these things and those things. And
• 27:05
  Speaker 1: so what they do is they develop these complicated models
• 27:08
  Speaker 1: and then they make predictions and they say, okay, well
• 27:10
  Speaker 1: the supernova should be this brighter, should last this long.
• 27:13
  Speaker 1: But the problem is we don't have that many observations
• 27:15
  Speaker 1: of supernova and we can't see inside them. We can
• 27:18
  Speaker 1: only basically see the light that they admit, well maybe
• 27:20
  Speaker 1: illuminate us. And what are some of the things we
• 27:22
  Speaker 1: don't know about supernova? Like we there's a lot we
• 27:25
  Speaker 1: don't understand about them, and what are some of these things?
• 27:28
  Speaker 1: So a lot of the things we don't understand us
• 27:29
  Speaker 1: about supernova involved what triggers that collapse, you know, what
• 27:33
  Speaker 1: is going on there, what makes that happen? How exactly
• 27:36
  Speaker 1: does that shock wave propagate to the core, how far
• 27:39
  Speaker 1: in does it get before the core starts to ignite?
• 27:41
  Speaker 1: And pushes back this question about when that turns around,
• 27:45
  Speaker 1: when them bounce exactly happens that we don't really understand.
• 27:48
  Speaker 1: But you know, more deeply than that, we just don't
• 27:50
  Speaker 1: understand matter at this density. You know, we think we understand,
• 27:54
  Speaker 1: for example, what happens when you take three quarks and
• 27:57
  Speaker 1: you put them together you get a proton or a neutron.
• 27:59
  Speaker 1: What hapens when you squeeze those protons and neutrons are
• 28:02
  Speaker 1: really really close together, so that it's more like a
• 28:05
  Speaker 1: six cork particle. Now do that with like a billion quarks.
• 28:09
  Speaker 1: What does that look like. It's the same kind of
• 28:11
  Speaker 1: question we ask about what's going on inside a neutron
• 28:14
  Speaker 1: star or what form of matter is happening inside a
• 28:17
  Speaker 1: black hole? These are all the same kinds of questions.
• 28:20
  Speaker 1: What happens when you squeeze things are really high temperatures
• 28:23
  Speaker 1: and pressures, and at lower energies. You know, we have
• 28:25
  Speaker 1: some ideas of the kind of things that happened, like
• 28:28
  Speaker 1: structures emerge. You get crystals of one temperature, and you
• 28:31
  Speaker 1: get gas at other temperatures, and you get fluids at
• 28:33
  Speaker 1: other temperatures. So there might be like whole new states
• 28:36
  Speaker 1: of matter that can be described by interesting new equations
• 28:39
  Speaker 1: that we've just never seen before, and this is the
• 28:41
  Speaker 1: way to probe it, to like say, what's going on
• 28:43
  Speaker 1: inside there? Well, create a shock wave that passes through it,
• 28:46
  Speaker 1: and let's understand how that chock wave propagates. And they
• 28:49
  Speaker 1: can tell you something about the phase of matter inside. Right.
• 28:52
  Speaker 1: It can maybe even tell us a little bit about
• 28:53
  Speaker 1: the Big Bang, right, because during the Big Bang you
• 28:56
  Speaker 1: also have these crazy conditions kind of like maybe what
• 28:58
  Speaker 1: do you see inside of a supernova? Yeah, the Big
• 29:01
  Speaker 1: Bang is like a huge supernova exactly. And it's very
• 29:03
  Speaker 1: hard for us to model those very early moments of
• 29:06
  Speaker 1: the universe because the forces are very very strong, very powerful.
• 29:10
  Speaker 1: And usually when we do modeling, we'd like to make
• 29:12
  Speaker 1: assumptions like we can ignore this, and we can ignore that,
• 29:14
  Speaker 1: we can ignore this other piece because it'd be too
• 29:16
  Speaker 1: complicated to model. But when everything is dense and all
• 29:19
  Speaker 1: the forces are at play, you can't ignore any of
• 29:21
  Speaker 1: those details, and the details really matter. You get them
• 29:24
  Speaker 1: a little bit wrong and your whole model is wrong.
• 29:27
  Speaker 1: So it's a very very challenging kind of thing to model,
• 29:29
  Speaker 1: and it's a kind of thing we'd really like to
• 29:31
  Speaker 1: learn about because we want to understand what the universe
• 29:34
  Speaker 1: was like in its first moments and what happens when
• 29:36
  Speaker 1: you squeeze matter to incredible densities. Yeah, and sometimes, like
• 29:40
  Speaker 1: you know, studying matter under those extreme conditions tell you
• 29:44
  Speaker 1: a lot about the matter itself, right like, your theories
• 29:47
  Speaker 1: can only go so far. There's a lot you can
• 29:48
  Speaker 1: learn about even like a person under extreme conditions, right Like,
• 29:52
  Speaker 1: it gives you a bigger picture about the matter. Absolutely,
• 29:54
  Speaker 1: And that's exactly why we have our series of podcast
• 29:56
  Speaker 1: about extreme conditions, like how strong can a magnet we'll get?
• 30:00
  Speaker 1: Or how fast can you get something spitting? And the
• 30:03
  Speaker 1: reason is those extremes tell you what the rules are,
• 30:06
  Speaker 1: and they tell you what the boundary conditions are for
• 30:08
  Speaker 1: the universe. That says you can't go faster than this,
• 30:10
  Speaker 1: or you can't have something denser than this, And those
• 30:14
  Speaker 1: are the places when the universe illuminates the edge cases.
• 30:18
  Speaker 1: Right it tells you exactly how things operate. Well, one
• 30:20
  Speaker 1: thing we do know about supernovas or supernova is that
• 30:24
  Speaker 1: they produced neutrinos and a lot of neutrinos, and then
• 30:27
  Speaker 1: those neutrinos might tell us kind of about what's going
• 30:31
  Speaker 1: on inside of the explosion. Yeah, I love neutrinos. They
• 30:34
  Speaker 1: are fascinating particle. They appear in all the like core
• 30:38
  Speaker 1: mysteries of the universe, not even just talking about like
• 30:41
  Speaker 1: astrophysics and supernovas. Just from a pure particle physics point
• 30:45
  Speaker 1: of view, neutrinos are super fascinating. That's sort of the
• 30:48
  Speaker 1: least well understood particle of all the particles that we
• 30:51
  Speaker 1: have discovered. Yeah, they're pretty mysterious and ghostily. But so
• 30:56
  Speaker 1: maybe tell us what do we know about neutrinos? What
• 30:58
  Speaker 1: are they? For those of those who, um, maybe I
• 31:01
  Speaker 1: don't know. The trinos are fascinating little particle. You're probably
• 31:04
  Speaker 1: familiar with the up cork and the down cork, which
• 31:06
  Speaker 1: make up the proton and the neutron that's in the
• 31:09
  Speaker 1: nucleus of the atom, and then around the atom you
• 31:11
  Speaker 1: have electrons of course, so those are the three particles
• 31:14
  Speaker 1: you need to make up like normal matter. But there's
• 31:17
  Speaker 1: another particle out there that's part of this core set,
• 31:20
  Speaker 1: and that's the neutrino that's paired with the electron. And
• 31:23
  Speaker 1: it's not part of the atom, like you are not
• 31:26
  Speaker 1: made out of neutrinos in any sense, but it's a
• 31:29
  Speaker 1: particle that sort of can exist in nature's menu and
• 31:32
  Speaker 1: it turns out there's lots of particles out there which
• 31:35
  Speaker 1: can exist. There's sort of like on the menu of
• 31:37
  Speaker 1: the universe, but don't exist under normal circumstances. Neutrinos are
• 31:42
  Speaker 1: especially weird kind because they ignore most of the forces
• 31:45
  Speaker 1: in the universe. Like they don't feel electromagnetism because they're neutral, right,
• 31:50
  Speaker 1: No trino means little neutral particle in Italian. And they
• 31:55
  Speaker 1: don't feel the strong force, right, they don't have a color.
• 31:58
  Speaker 1: Those the two most powerful forces in universe. So all
• 32:01
  Speaker 1: they're left with is the weak force. And of course gravity,
• 32:04
  Speaker 1: which is like so ridiculously weak we don't even think
• 32:06
  Speaker 1: about it when it comes to particles. So neutrinos are
• 32:09
  Speaker 1: these little neutral particles that only feel the weak force.
• 32:13
  Speaker 1: It's almost like they're ignoring the rest of the universe
• 32:16
  Speaker 1: in a way, right, Like most of the universe, like
• 32:18
  Speaker 1: our particles talked to each other through these other forces.
• 32:21
  Speaker 1: But Newtinas are like, Nope, I'm just not gonna check
• 32:24
  Speaker 1: Twitter or Facebook. I'm just gonna only accept handwritten letters
• 32:27
  Speaker 1: unless they're junk male from the Daniel Foundation. Yeah, and
• 32:30
  Speaker 1: you know, the neutrino was actually discovered by a professor
• 32:33
  Speaker 1: here at UC Irvine, for which he won the Nobel Prize.
• 32:36
  Speaker 1: And in my office I can often hear tours of
• 32:39
  Speaker 1: campus going by, and as they pass the physics building,
• 32:41
  Speaker 1: they say, and this is Ryness Hall, named after Fred Ryness,
• 32:45
  Speaker 1: who discovered the neutrino, the smallest fundamental particle. That always
• 32:49
  Speaker 1: makes me cringe because I'm like, the neutrino is not
• 32:52
  Speaker 1: smaller than the electron or the quirk. They're all the
• 32:54
  Speaker 1: same size, they're all points. But they call it the
• 32:56
  Speaker 1: smallest particle because of its ability to pass us through stuff.
• 33:01
  Speaker 1: Because it only feels the weak force, it can pass
• 33:04
  Speaker 1: through an incredible amount of matter without interacting with it. Well,
• 33:08
  Speaker 1: it's also small in this sense that it has very
• 33:10
  Speaker 1: little mass, right, Like it does feel gravity, but it's
• 33:13
  Speaker 1: just has very little mass for it to kind of
• 33:16
  Speaker 1: obey gravity. That's right. It does have non zero mass.
• 33:19
  Speaker 1: Like we know neutrinos have some mass, but we don't
• 33:22
  Speaker 1: know exactly what their masses. But they are very very small,
• 33:25
  Speaker 1: especially compared to the electron. Wait, did you say neutrinos
• 33:28
  Speaker 1: are very small? Their mass is very small, especially compared
• 33:32
  Speaker 1: to the electron. But you know they're not the lowest
• 33:35
  Speaker 1: mass particle right photons and zero mass blue ones have
• 33:38
  Speaker 1: zero mass. The reason people call them small, I think,
• 33:41
  Speaker 1: is because they're trying to understand how it is. And
• 33:43
  Speaker 1: neutrino can like pass through the entire Earth without even noticing.
• 33:47
  Speaker 1: They wanted to like slip through all those particles and
• 33:50
  Speaker 1: like slide around them without interacting. But a better way
• 33:54
  Speaker 1: to think about it is in terms of like transparency.
• 33:57
  Speaker 1: You know, light can go through your window without interacting
• 34:01
  Speaker 1: with glass. It can pass through right or through the air.
• 34:04
  Speaker 1: The air is transparent to light. It's not like the
• 34:06
  Speaker 1: lightest sliding around and avoiding all those molecules. It just
• 34:11
  Speaker 1: doesn't interact with them. It doesn't have the right frequency
• 34:13
  Speaker 1: to get absorbed by those molecules. And so those molecules
• 34:16
  Speaker 1: just ignore each other. They pass right through each other.
• 34:20
  Speaker 1: And that's what's happening with neutrinos. Neutrinos see the whole
• 34:23
  Speaker 1: universe as almost transparent, right, so they just pass right
• 34:27
  Speaker 1: through without even noticing. Yeah, they're just ignoring everyone. Everyone's like, hey,
• 34:30
  Speaker 1: talk to us with this strong force or the electroman
• 34:33
  Speaker 1: game for us, and they're like, nope, which is cruising
• 34:35
  Speaker 1: through you said, they're related to the electron. What does
• 34:38
  Speaker 1: that mean? Or they're paired with the electron, what does
• 34:40
  Speaker 1: that mean. We have all these rules and particle physics
• 34:42
  Speaker 1: about like what can decay into what? And for example,
• 34:46
  Speaker 1: a W boson it can decay into an upcork and
• 34:49
  Speaker 1: a down cork. You can also decay into an electron
• 34:52
  Speaker 1: and an electron neutrino. So the electron and electron neutrino
• 34:56
  Speaker 1: sort of like paired together by the W. W can't
• 34:59
  Speaker 1: for example, to came into an up cork and a
• 35:01
  Speaker 1: neutrino or a down cork and an electron, and so
• 35:05
  Speaker 1: they have this sort of relationship in the weak force
• 35:07
  Speaker 1: of the electron and the neutrino have exactly one electric
• 35:11
  Speaker 1: charge step between them negative one and zero, just like
• 35:14
  Speaker 1: the down cork and the upcork have an exactly one
• 35:17
  Speaker 1: electric charge between them. So we group them together into
• 35:20
  Speaker 1: these pairs for that reason. They're sort of like made
• 35:23
  Speaker 1: together or they go well together. Yeah, And for those
• 35:26
  Speaker 1: of you who think quantum mechanically and in terms of
• 35:28
  Speaker 1: quantum fields, you know, the W particle sort of like
• 35:31
  Speaker 1: raises an electron into a neutrino, or the other W
• 35:34
  Speaker 1: can turn in a neutrino into an electron. It's sort
• 35:37
  Speaker 1: of like converts these fields from one to the other.
• 35:39
  Speaker 1: Or if you remember our episode about gauge symmetry, like
• 35:43
  Speaker 1: the whole reason we have forces and force particles is
• 35:45
  Speaker 1: to preserve these weird symmetries that fill all of space. Well,
• 35:49
  Speaker 1: the w particle does that, and it pairs the neutrino
• 35:51
  Speaker 1: and the electron together. They have a symmetry together, the
• 35:55
  Speaker 1: electron and the neutrino. I see the like the neutrino
• 35:58
  Speaker 1: doesn't pair us well with others. It somehow kind of
• 36:01
  Speaker 1: in the same category as electrons. Yeah, and we have
• 36:03
  Speaker 1: this thing called electron number, which is conserved, Like you
• 36:07
  Speaker 1: can't increase or decrease the number of electrons in the universe,
• 36:12
  Speaker 1: but neutrinos are a counted as electrons for that category. Interesting,
• 36:17
  Speaker 1: it's like a non non electron electron and the muon
• 36:21
  Speaker 1: and the tow which is like the weird heavy versions
• 36:23
  Speaker 1: of the electron. They have their own neutrino. There's a
• 36:26
  Speaker 1: muon neutrino and a tow neutrino, and there's a number
• 36:29
  Speaker 1: of muons that's conserved in the universe, and a number
• 36:32
  Speaker 1: of towels, and so each of those is paired with
• 36:34
  Speaker 1: their own lepton in that way, all right, So they're
• 36:37
  Speaker 1: ghostly particles that go through the universe, ignoring everybody else,
• 36:41
  Speaker 1: it seems. But what's weird is that they're produced um
• 36:44
  Speaker 1: not just in supernova, but they're produced by our son.
• 36:46
  Speaker 1: Like our son produces a huge amount of neutrinos, and
• 36:49
  Speaker 1: so it's weird to think that something in our universe
• 36:52
  Speaker 1: that likes to talk to us, that has electromagnetic forces
• 36:56
  Speaker 1: and all the other forces make make things that then
• 36:59
  Speaker 1: ignore the forces. Yeah, our Sun, it turns out, produces
• 37:02
  Speaker 1: an incredible number of neutrinos. It's like you know, you're
• 37:05
  Speaker 1: following somebody on Instagram and then you discover, oh my god,
• 37:08
  Speaker 1: they're huge on TikTok and I never even knew. Our
• 37:11
  Speaker 1: son produces so many new trinos that even here on
• 37:14
  Speaker 1: Earth there are a hundred billion passing through your fingernail
• 37:18
  Speaker 1: every second. So a hundred billion per square centimeter per
• 37:22
  Speaker 1: second is the flux on Earth. Now, imagine like how
• 37:25
  Speaker 1: many neutrinos passed through a square centimeter if you're right
• 37:28
  Speaker 1: on the surface of the Sun. It's just mind boggling.
• 37:31
  Speaker 1: How many there are because, as you said, like during
• 37:33
  Speaker 1: in these sort of like quantum or particle reactions, they
• 37:36
  Speaker 1: just get produced along with all the other stuff that
• 37:38
  Speaker 1: gets produced in these reactions. Yeah, the fusion that happens
• 37:42
  Speaker 1: inside the Sun, and this is not even during a supernova,
• 37:44
  Speaker 1: just normal everyday burning of the Sun also involves the
• 37:48
  Speaker 1: weak force, which means that neutrinos are produced. Can't remove
• 37:51
  Speaker 1: an electron without producing a new trino for example, because
• 37:54
  Speaker 1: of this conservation of the number of electrons, which includes neutrinos,
• 37:57
  Speaker 1: weirdly do you end up with lots of neutrinos produced
• 38:00
  Speaker 1: in those reactions. And one thing I think is super
• 38:02
  Speaker 1: cool is that if you only have a neutrino detector,
• 38:06
  Speaker 1: you can use it to take a picture of the Sun.
• 38:09
  Speaker 1: In neutrinos. You can make like an image of the
• 38:12
  Speaker 1: Sun in neutrinos. If you didn't have eyeballs and you
• 38:15
  Speaker 1: couldn't see photons, you could still tell that the Sun
• 38:17
  Speaker 1: was there just by using neutrinos, right, Yeah, I mean
• 38:21
  Speaker 1: it's sort of like if you couldn't see visible light,
• 38:23
  Speaker 1: but you could see other frequencies of light, you would
• 38:25
  Speaker 1: still know the Sun is there because it's producing across
• 38:27
  Speaker 1: all these frequencies. Absolutely, Remember it's a different kind of particle.
• 38:31
  Speaker 1: It's not just a different frequency photon. It's like a
• 38:34
  Speaker 1: completely different way to get information. It's like seeing a
• 38:38
  Speaker 1: car versus hearing a car. You're using a completely different
• 38:41
  Speaker 1: sense to now detect it. And if you google, you
• 38:43
  Speaker 1: can actually google like picture of the Sun in neutrinos,
• 38:47
  Speaker 1: and you can see this image that was made of
• 38:49
  Speaker 1: the Sun using neutrinos. I think it's super cool. Oh
• 38:52
  Speaker 1: so it's almost in a good way that we can
• 38:54
  Speaker 1: then turns don't interact with us. Like if neutrinos interactive
• 38:57
  Speaker 1: with us, they might fry us from all the nutrin
• 39:00
  Speaker 1: just coming out of the Sun, Like we would get
• 39:01
  Speaker 1: into trino sunburned, neutrino cancer. That's something I've never heard
• 39:04
  Speaker 1: of before, but you're right, it's an incredible amount of rediation.
• 39:07
  Speaker 1: On the other hand, maybe we could build like neutrinos
• 39:10
  Speaker 1: solar panels and that would solve our energy problems. Oh. Interesting,
• 39:15
  Speaker 1: that's a science fiction story for you right there. All right, Well, um,
• 39:21
  Speaker 1: so the Sun produces a lot of neutrinos, and supernovas
• 39:25
  Speaker 1: produce a lot of the trinos. So let's get into
• 39:27
  Speaker 1: what we can learn from them about what's going on
• 39:29
  Speaker 1: inside of these stellar explosions. But first, let's take another
• 39:33
  Speaker 1: quick break. All Right, we're talking about supernovas and what
• 39:49
  Speaker 1: can neutrinos tell us about them, because I guess um,
• 39:52
  Speaker 1: a lot of trinos get produced in the supernova, a
• 39:54
  Speaker 1: lot of neutrinos get produced in a supernova. In fact,
• 39:58
  Speaker 1: neutrinos carry away most the energy of a supernova. You
• 40:02
  Speaker 1: thought a supernova was bright and visible light, and it is.
• 40:05
  Speaker 1: That's nothing compared how bright it is in neutrinos. What
• 40:09
  Speaker 1: do you mean as bright? Like? As much more energy
• 40:12
  Speaker 1: is produced in the ne trinos than are made in
• 40:14
  Speaker 1: a supernova than act than regular light. A hundred times
• 40:19
  Speaker 1: of the energy produced in a supernova is carried away
• 40:23
  Speaker 1: in new trinos. So if you're just looking at a
• 40:25
  Speaker 1: supernova in the visible light, you're getting one percent of
• 40:29
  Speaker 1: its energy. WHOA, that's like a lot. That's like supernova
• 40:34
  Speaker 1: is mostly a a trino explosion. Yes, it's mostly a
• 40:37
  Speaker 1: neutrino explosion. It's like autrino explosion. Yeah, we've been following
• 40:41
  Speaker 1: it on Twitter, but it's been on TikTok this whole time.
• 40:44
  Speaker 1: And you know these supernovas, they're not small even in
• 40:47
  Speaker 1: the visible light. And there's some of these that are
• 40:48
  Speaker 1: just mind bogglingly bright in the visible light, like one
• 40:52
  Speaker 1: called a s A S S N fifteen l H
• 40:56
  Speaker 1: was a trillion times brighter than our sun momentarily. That's
• 40:59
  Speaker 1: like ten times as bright as our entire galaxy. And
• 41:03
  Speaker 1: that's in the visible light. Multiplied that by a hundred,
• 41:06
  Speaker 1: and that's the intensity of the energy carried away by
• 41:09
  Speaker 1: the neutrinos. WHOA, So I guess what's going on? Like
• 41:13
  Speaker 1: how you're saying, like for every little explosion that's happening
• 41:16
  Speaker 1: inside of supernova, it's producing a hundred times more neutrinos
• 41:20
  Speaker 1: than any anything else. Absolutely, the number of neutrinos produced
• 41:24
  Speaker 1: by supernova is something like ten to the fifty. That's
• 41:28
  Speaker 1: ten with fifty zeros after it, and some models go
• 41:32
  Speaker 1: up to predicting ten to the sixty. So it's an
• 41:35
  Speaker 1: incredible number. What's happening is that the nucleus of this
• 41:38
  Speaker 1: star is getting compressed, and so you have protons in there,
• 41:41
  Speaker 1: and you have some electrons that are in there, and
• 41:44
  Speaker 1: they get squeezed down to the electron and the proton
• 41:47
  Speaker 1: actually fused together and they turn into a neutron. So
• 41:51
  Speaker 1: that's called electron capture. But remember there's this conservation of
• 41:55
  Speaker 1: the number of electrons. You can't just delete an electron
• 41:58
  Speaker 1: from the universe. What happened is the proton and the
• 42:01
  Speaker 1: electron turn into a neutron, but they also pop out
• 42:04
  Speaker 1: a neutrino, so it's called the neutron ization of the core.
• 42:08
  Speaker 1: You make this thing super duper dense. You squeeze the
• 42:10
  Speaker 1: electrons and protons together to make neutrons. Plus you make
• 42:14
  Speaker 1: a neutrino every time that happens. Wait what Wait, so
• 42:17
  Speaker 1: you you can squeeze an electron and a proton together,
• 42:20
  Speaker 1: but they're like plus and minus. Wouldn't that like that's
• 42:23
  Speaker 1: how intense things are. They can overcome that basic repulsion. Well,
• 42:27
  Speaker 1: they're plus a mindus, so they're attracted to each other. Right,
• 42:29
  Speaker 1: That's how the electron is bound around the proton. But
• 42:32
  Speaker 1: typically electrons don't like to get squeezed down into the
• 42:35
  Speaker 1: nucleus because a quantum particle has a minimum energy. Like
• 42:39
  Speaker 1: you can find a quantum particle, it can't go down
• 42:42
  Speaker 1: to zero energy. You know have for example, if you
• 42:44
  Speaker 1: have a bowl and you put a marble in it
• 42:46
  Speaker 1: you can just sit at the bottom of the bowl
• 42:48
  Speaker 1: with no energy. It was a quantum marble. It couldn't
• 42:51
  Speaker 1: go to the bottom of the bowl. It would have
• 42:52
  Speaker 1: like a minimum energy level in which it would be
• 42:55
  Speaker 1: buzzing around. That's why electrons don't collapse into protons, and
• 42:58
  Speaker 1: normally they resist this because the Heisenberg and certainty principle says,
• 43:02
  Speaker 1: if you localize the electron, if you squeeze it down
• 43:04
  Speaker 1: to a small space, then it's gonna have a lot
• 43:06
  Speaker 1: of energy, has a lot of uncertainty in its momentum.
• 43:09
  Speaker 1: And so what's happening here is you're overcoming that with
• 43:11
  Speaker 1: the pressure. You're squeezing these electrons down into the proton
• 43:15
  Speaker 1: where they don't actually want to go, and turning it
• 43:18
  Speaker 1: into a neutron. A neutron and a neutrino, I guess
• 43:21
  Speaker 1: because the plus and the minus canceled out, but some
• 43:24
  Speaker 1: of that energy has to go somewhere. Yeah. It's really
• 43:26
  Speaker 1: interesting because you go from two charged particles a plus
• 43:28
  Speaker 1: a negative to two neutral particles. So it's like the
• 43:31
  Speaker 1: neutralization of the core. You get a neutron and a neutrino,
• 43:35
  Speaker 1: but a proton is really just made out of quarks,
• 43:38
  Speaker 1: and so it's it's actually more complicated, right, it's like
• 43:40
  Speaker 1: a minus one plus a two thirds minus two one
• 43:45
  Speaker 1: third or something like that. Yeah, what's actually happening is
• 43:47
  Speaker 1: that you have one of the quarks inside the neutron
• 43:50
  Speaker 1: emits the W changing into a different kind of quirk.
• 43:52
  Speaker 1: So that changes the proton into a neutron, and then
• 43:55
  Speaker 1: that W interacts with the electron and converts into a neutrino.
• 43:59
  Speaker 1: So that's what's putting sort of microscopically from the particle
• 44:02
  Speaker 1: physics point of view. All right, So then you push
• 44:05
  Speaker 1: together the electron on the proton and creates a neutrino,
• 44:08
  Speaker 1: and it creates a whole bunch of neutrinos in this
• 44:11
  Speaker 1: supernova explosion, and so that's really useful because, like neutrinos
• 44:15
  Speaker 1: are then easier to see kind of through the explosion,
• 44:18
  Speaker 1: so you could sort of get a trans X ray
• 44:20
  Speaker 1: picture almost of the supernova. One of the reasons that
• 44:23
  Speaker 1: you have so much energy released in terms of neutrinos
• 44:27
  Speaker 1: is that the star is mostly transparent to those neutrinos.
• 44:30
  Speaker 1: So when the neutrino is produced, it can fly out
• 44:33
  Speaker 1: from the star it's this crazy, incredible intense explosion that's happening.
• 44:37
  Speaker 1: But once you've made the neutrino is mostly able to
• 44:40
  Speaker 1: just escape and fly out into the universe. So every
• 44:43
  Speaker 1: time you get energy dumped into a neutrino boom, that's released.
• 44:46
  Speaker 1: On the other hand, if it turns into a photon,
• 44:48
  Speaker 1: that photon is created inside a really incredibly high dense
• 44:52
  Speaker 1: environment with all sorts of charged particles that it will
• 44:54
  Speaker 1: interact with, and so it gets reabsorbed very quickly. So
• 44:57
  Speaker 1: neutrinos fly right out of the superno of a, whereas
• 45:00
  Speaker 1: photons are mostly reabsorbed. If you see a photon from
• 45:03
  Speaker 1: the supernova, it was only emitted from the surface of
• 45:06
  Speaker 1: the supernova, not from the core. Interesting and in fact,
• 45:09
  Speaker 1: you're saying that because matrinos are can fly through the explosion,
• 45:13
  Speaker 1: they sort of get here first before any actual light
• 45:17
  Speaker 1: from the explosion. That's really counterintuitive, but supernova neutrinos arrived
• 45:21
  Speaker 1: here before photons. You might think, how is that possible.
• 45:25
  Speaker 1: Photons travel with the speed of light. Neutrinos have a
• 45:27
  Speaker 1: little bit of mass, so they don't travel at the
• 45:30
  Speaker 1: speed of light. But the answer is that they are
• 45:32
  Speaker 1: released first. Supernova. Neutrinos can leave the core of the
• 45:35
  Speaker 1: supernova and fly immediately towards the Earth, but photons don't
• 45:39
  Speaker 1: get released immediately when the supernova starts. You need like
• 45:42
  Speaker 1: that shock wave to travel through the star and then
• 45:45
  Speaker 1: emit at the edge of the star. So that sort
• 45:48
  Speaker 1: of limited first by the speed of sound propagating that
• 45:50
  Speaker 1: chock wave, and then when the shock wave hits the
• 45:52
  Speaker 1: surface of the star, then photons from the surface can leave,
• 45:56
  Speaker 1: and they'll spend their whole time trying to catch up
• 45:59
  Speaker 1: to those neutrinos us and not quite making it. It's
• 46:02
  Speaker 1: almost like the supernova in a way traps the visible
• 46:05
  Speaker 1: light so it can leave. We can't see the explosion
• 46:08
  Speaker 1: until afterwards, but the trinos can just fly out and
• 46:11
  Speaker 1: tells like, hey, supernova happened. Yeah, And it's the similar
• 46:16
  Speaker 1: things what happens inside our sun. You sometimes hear people
• 46:19
  Speaker 1: say that it takes a photon thousands of years to
• 46:22
  Speaker 1: travel from the center of the Sun to the surface.
• 46:24
  Speaker 1: It's a bit misleading because you know, what's actually happening
• 46:27
  Speaker 1: is a photon created at the center is just reabsorbed
• 46:30
  Speaker 1: and then the whole sun heats up and later it
• 46:32
  Speaker 1: emits a photon at the surface, but the principle is
• 46:34
  Speaker 1: the same that a photon created the heart of our
• 46:37
  Speaker 1: Sun also can't just leave the Sun and shine out
• 46:39
  Speaker 1: to Earth. Only photons from the surface can make it
• 46:42
  Speaker 1: from the Sun and hit the Earth. So you can
• 46:44
  Speaker 1: actually use new trinos as like an early warning system
• 46:47
  Speaker 1: for supernovas. But it wouldn't that depend on how far
• 46:51
  Speaker 1: away the supernova is, Like, if it's far enough away,
• 46:54
  Speaker 1: the photons will catch up eventually. Yes, if it is
• 46:57
  Speaker 1: far enough away, the photons will catch up because they're
• 46:59
  Speaker 1: going fat saster than the neutrinos. Yeah, but neutrinos are
• 47:02
  Speaker 1: really really light. Their mass is very very small, and
• 47:05
  Speaker 1: so they travel an incredibly high fraction of the speed
• 47:09
  Speaker 1: of light, you know, like point and so you're right,
• 47:13
  Speaker 1: photons are traveling faster, and so eventually they will overtake it.
• 47:16
  Speaker 1: But they'd have to come from extremely distant supernova for
• 47:19
  Speaker 1: that to happen, and all the supernovas we see are
• 47:21
  Speaker 1: pretty distant. You know, we haven't seen one in our
• 47:24
  Speaker 1: galaxy since sixteen hundreds, Like the last person to see
• 47:27
  Speaker 1: a supernova in the Milky Way was Kepler, whoa in
• 47:31
  Speaker 1: sixteen o four, like it's been a while, and that's
• 47:34
  Speaker 1: sort of a puzzle, like not we don't really understand it.
• 47:37
  Speaker 1: We're supposed to get like one to three per century,
• 47:39
  Speaker 1: and it's been like four hundred years and we've gotten zero.
• 47:42
  Speaker 1: So that's something nobody understands about supernova Like, if something
• 47:47
  Speaker 1: one happens in our Milky Way, it would be more
• 47:49
  Speaker 1: than just like a light shining getting brighter. It would
• 47:52
  Speaker 1: maybe be super bright light light up the nights. Guy,
• 47:54
  Speaker 1: it would And we saw a supernova in seven, not
• 47:58
  Speaker 1: from our actual gaxe or from like a nearby blob
• 48:02
  Speaker 1: from the Magellanic cloud. And this is in seven. They
• 48:06
  Speaker 1: saw this supernova it's called Supernovae A, and they actually
• 48:10
  Speaker 1: saw neutrinos from it before they saw the light from it. WHOA,
• 48:15
  Speaker 1: meaning like we had some lutrino detectors ready to go,
• 48:18
  Speaker 1: and we saw a spike before we saw the actual
• 48:20
  Speaker 1: flash exactly. We have particle physicists studying neutrinos just because
• 48:24
  Speaker 1: we want to understand like how often does an electron
• 48:26
  Speaker 1: neutrino turn into a muan neutrino or this kind of
• 48:29
  Speaker 1: like basic particle physics questions. So we have these neutrino telescopes,
• 48:33
  Speaker 1: like the when we talked about earlier that took a
• 48:35
  Speaker 1: picture of the Sun in neutrinos. So these things are
• 48:38
  Speaker 1: always running, they're always sensitive. In the late seventies, a
• 48:41
  Speaker 1: couple of theorists had this prediction. They said, you know what,
• 48:44
  Speaker 1: we did this calculation. We predict that when a supernova happens,
• 48:47
  Speaker 1: there will be an incredible flux of neutrinos. Nobody had
• 48:50
  Speaker 1: ever thought that before. And then ten years later, after
• 48:54
  Speaker 1: these neutrino telescopes were built, they saw one. They saw
• 48:56
  Speaker 1: this flux, this momentary flash of neutrino knows that nobody
• 49:01
  Speaker 1: was expecting. And a few hours later they saw a
• 49:04
  Speaker 1: bright light from the same direction, and so that was
• 49:06
  Speaker 1: the supernova. In two different kinds of signals, we got
• 49:10
  Speaker 1: the preview, like the Trader kind of for the for
• 49:14
  Speaker 1: the main event exactly, or I guess not, because in
• 49:16
  Speaker 1: the Trina explosion is the main event of the event, Yeah, exactly.
• 49:21
  Speaker 1: The supernova itself is like the post credit scene. Yeah,
• 49:24
  Speaker 1: it's just it's just the the event, just sitting around
• 49:29
  Speaker 1: eating schwarma. But we only saw like twenty five neutrinos,
• 49:33
  Speaker 1: and that's a lot that's a lot of neutrinos. In
• 49:35
  Speaker 1: order to detect twenty five neutrinos, you need to have
• 49:37
  Speaker 1: billions and trillions of neutrinos passing through your detector, because
• 49:41
  Speaker 1: remember it's very rare that they interact, so most of
• 49:44
  Speaker 1: the neutrinos will pass right through you. So they saw
• 49:47
  Speaker 1: like twenty five neutrinos over a span of like thirteen seconds,
• 49:51
  Speaker 1: which is like nobody ever sees a new Trina detector
• 49:53
  Speaker 1: lighting up like that. They were going crazy. But this
• 49:56
  Speaker 1: is the only time it's ever happened. This is the
• 49:57
  Speaker 1: only supernova we've ever seen neutra arinos from. But I mean,
• 50:01
  Speaker 1: we have these neutrino telescopes running all the time, and
• 50:04
  Speaker 1: aren't there supernovs happening all the time. Shouldn't we see
• 50:06
  Speaker 1: these neutrino events then as all the time as well?
• 50:10
  Speaker 1: Yeah we should, But a lot of these supernovas are
• 50:12
  Speaker 1: very distant. Was sort of unusually close. It was in
• 50:16
  Speaker 1: this blob that orbits the Milky Way to Magel in
• 50:18
  Speaker 1: a cloud. Most of the supernovas we see are in
• 50:21
  Speaker 1: much more distant galaxies, And so the number of neutrinos
• 50:24
  Speaker 1: we get and the number we can detect is very,
• 50:26
  Speaker 1: very small, but we do expect that all these neutrinos
• 50:29
  Speaker 1: from all these distant supernovas sort of add up to
• 50:32
  Speaker 1: be like an overall supernova neutrino background, which we hope
• 50:36
  Speaker 1: the next generation of telescopes will be able to see.
• 50:39
  Speaker 1: So even if you can't like individually identify neutrinos from
• 50:42
  Speaker 1: one supernova, you might be able to tell that there
• 50:45
  Speaker 1: are a lot of supernovas out there producing a lot
• 50:47
  Speaker 1: of neutrinos that you can pick up. Interesting. Well, I
• 50:50
  Speaker 1: guess maybe to answer the question of the episode, then,
• 50:53
  Speaker 1: what can neutrinos tell us about supernova? What do you
• 50:55
  Speaker 1: think they'll tell us if we can maybe see these
• 50:58
  Speaker 1: a little bit better or a better resolution, and they
• 51:01
  Speaker 1: can tell us a lot about what's going on inside
• 51:03
  Speaker 1: the supernova. Because neutrinos have three different flavors electrons, muans,
• 51:07
  Speaker 1: and towels, And while most of the neutrinos produced in
• 51:11
  Speaker 1: the heart are electron neutrinos, as they fly through the star,
• 51:14
  Speaker 1: they change from electron to muan to taw, this process
• 51:17
  Speaker 1: called neutrino oscillation. We have a whole podcast episode about that,
• 51:21
  Speaker 1: and that happens based on the density of the material
• 51:24
  Speaker 1: and the kind of the material. So by looking at
• 51:26
  Speaker 1: like the ratios of electrons and muans and town neutrinos,
• 51:30
  Speaker 1: you can tell something about the density of the material.
• 51:32
  Speaker 1: It's sort of like X raying the supernova. You can
• 51:35
  Speaker 1: see what happened on the inside, not just on the surface.
• 51:38
  Speaker 1: I see because maybe in this signal, this explosion of neutrinos,
• 51:42
  Speaker 1: you can tell, oh, first there was this kind and
• 51:44
  Speaker 1: then it changed into this other kind of neutrino, and
• 51:47
  Speaker 1: then that would tell you kind of how the explosion
• 51:50
  Speaker 1: um evolved. Can tell you something about the density and
• 51:53
  Speaker 1: the layers of what's going on inside the supernova. And
• 51:56
  Speaker 1: so there's sort of like the messenger of the core
• 51:59
  Speaker 1: of the supernova mechanism. You're saying, like, right now we
• 52:02
  Speaker 1: have we can have a neutrino telescope look at our
• 52:04
  Speaker 1: son and get a picture of our son. But right
• 52:07
  Speaker 1: now we don't have the technology too and get a
• 52:09
  Speaker 1: picture of a supernova in neutrinos, not most of them,
• 52:12
  Speaker 1: because neutrinos are so poorly interacting. Even supernovas that are
• 52:16
  Speaker 1: super duper bright, we can't resolve most of them. It's
• 52:18
  Speaker 1: just like how there are lots of black holes out
• 52:21
  Speaker 1: there and meeting lots of gravitational waves. But it's not
• 52:23
  Speaker 1: always easy to pick out one gravitational wave from one
• 52:27
  Speaker 1: black hole because there's so many and they're so distant,
• 52:30
  Speaker 1: so they all add up to sort of like a buzz.
• 52:32
  Speaker 1: You want to pick out one specific supernova, it's got
• 52:35
  Speaker 1: to be kind of bright and kind of nearby. But
• 52:37
  Speaker 1: we're building the next generation of new trino detectors which
• 52:41
  Speaker 1: should be even more sensitive to neutrinos, so we should
• 52:44
  Speaker 1: be able to see supernovas and other galaxies in neutrinos,
• 52:48
  Speaker 1: and they'll give us the information we need to start
• 52:51
  Speaker 1: like answering some of these questions about what's going on
• 52:54
  Speaker 1: when this core collapses. You're saying, like, right now we
• 52:57
  Speaker 1: have more like a micro like a neutrino microphone was
• 53:00
  Speaker 1: in a way, but maybe in the future will have
• 53:01
  Speaker 1: more like a telescope natrino telescope, like a focused scope
• 53:06
  Speaker 1: for it exactly. And the Daniel Science Foundation very excited
• 53:09
  Speaker 1: to find that when junk mail and we could have
• 53:13
  Speaker 1: a supernova early warning system. Right if we could detect
• 53:16
  Speaker 1: these things happening before they shine in the visible light,
• 53:19
  Speaker 1: then we can point our telescopes to them hours before
• 53:22
  Speaker 1: they become luminous, and we can really see what happens
• 53:25
  Speaker 1: just before the shock wave reaches the surface, which would
• 53:28
  Speaker 1: be super fascinating interesting, be like having a third eyeball
• 53:32
  Speaker 1: looking out for the next supernova. Yeah, you can also
• 53:35
  Speaker 1: turn it the other way around. Not only can new
• 53:37
  Speaker 1: trinos tell something about supernovas, but this one supernova also
• 53:43
  Speaker 1: told us something about new trinos. Oh yeah, you mean,
• 53:46
  Speaker 1: like there's still a lot we don't know about neutrinos, right, Yeah,
• 53:48
  Speaker 1: And in the nineteen eighties we have no idea what
• 53:51
  Speaker 1: the massive neutrinos was, like, how small was it? Exactly?
• 53:54
  Speaker 1: The very difficult experiments to do. So when we got
• 53:57
  Speaker 1: this pulse of neutrinos from that supernova, actually used it
• 54:01
  Speaker 1: to figure out roughly how much mass does the neutrino
• 54:04
  Speaker 1: have based on the difference in arrival times of neutrinos,
• 54:08
  Speaker 1: Like two neutrinos are produced in the supernova at the
• 54:11
  Speaker 1: same time but with different energies, which means slightly different velocities,
• 54:15
  Speaker 1: and we can measure the arrival time on Earth and
• 54:18
  Speaker 1: the energy on Earth, and then you do a bunch
• 54:20
  Speaker 1: of math and you can figure out exactly what the
• 54:22
  Speaker 1: mass of that neutrino had to be if it had
• 54:24
  Speaker 1: this energy and this velocity. So we're able to figure
• 54:27
  Speaker 1: out roughly what the mass of the neutrino was because
• 54:30
  Speaker 1: we got a nice big blob of them from this supernova.
• 54:34
  Speaker 1: And what you've learned is that it's a really small
• 54:37
  Speaker 1: or really light. It's really really small mass exactly. The
• 54:40
  Speaker 1: electron neutrino is some mass less than like twenty five
• 54:44
  Speaker 1: e v, and in comparison, the electron has a mass
• 54:47
  Speaker 1: of five hundred thousand ev. So the neutrino is much much, much,
• 54:52
  Speaker 1: much much lower mass than even the electron, which is
• 54:55
  Speaker 1: very low mass compared to lots of other particles. It's
• 54:58
  Speaker 1: interesting that you know, so much a the energy of
• 55:00
  Speaker 1: a supernova is trying into neutrinos. But then neutrinos are
• 55:04
  Speaker 1: you know, ghostly and super light, so they're almost like
• 55:07
  Speaker 1: impossible to see. Yeah, Like photons, they carry their energy
• 55:11
  Speaker 1: mostly in their motion, not in their mass. Right, Photons
• 55:15
  Speaker 1: are pure motion, they're just kinetic energy to have momentum
• 55:18
  Speaker 1: but no mass. Neutrinos also have momentum and they have
• 55:21
  Speaker 1: a very very small amount of mass, all right, So
• 55:25
  Speaker 1: stay tuned for these new neutrino telescopes funded by the
• 55:28
  Speaker 1: Daniel Junk Mail Foundation, which my one day gave everyone
• 55:32
  Speaker 1: a next eyeball, at least internal eyeball for us to
• 55:36
  Speaker 1: see the universe in other types of energies. That's right,
• 55:40
  Speaker 1: and if you would like to support the mission of
• 55:41
  Speaker 1: the Daniel Science Foundation, please send us a check or
• 55:44
  Speaker 1: at least send us some junk mail. Daniel will recycle
• 55:48
  Speaker 1: it and use that to make more junk mail. I
• 55:51
  Speaker 1: guess it's just a junk mail making operations. You caught me.
• 55:56
  Speaker 1: It's just a big spam. It's a hobby, Daniel. Let's
• 55:59
  Speaker 1: let's face it. One day I want to build a
• 56:00
  Speaker 1: junk male detector. That would be my next kind of eyeball.
• 56:03
  Speaker 1: I'll focus on the Anverse to find the greatest sources
• 56:06
  Speaker 1: of junk male in the universe. I see, yeah, well,
• 56:09
  Speaker 1: I think every house is a junk male detector, or
• 56:12
  Speaker 1: at least a junk male collector. But maybe you could
• 56:15
  Speaker 1: do like a citizen science project where you coordinate, you know,
• 56:18
  Speaker 1: different households, and then you could pinpoint the source of
• 56:21
  Speaker 1: these junk males junk male telescope network. I might tell
• 56:25
  Speaker 1: you a lot about the postal universe. Yeah, all right,
• 56:28
  Speaker 1: we'll stay tuned. And again just another reminder that there's
• 56:31
  Speaker 1: a lot going on in this universe that is maybe
• 56:34
  Speaker 1: not apparent to the naked eye. You know, there's a
• 56:36
  Speaker 1: lot of interesting science and physics and incredible energy is
• 56:40
  Speaker 1: being released out there that are regular human eyes can't see.
• 56:44
  Speaker 1: So we're sort of in our everyday lives kind of
• 56:46
  Speaker 1: ignorant about all of this amazing and miraculous processes going
• 56:51
  Speaker 1: on in in nature. Yeah, and those are the things
• 56:53
  Speaker 1: that we know we don't know about. There might even
• 56:56
  Speaker 1: be more things, the unknown unknowns, that we don't even
• 56:59
  Speaker 1: know that we can see. And it could be going
• 57:01
  Speaker 1: on right under our very eyeballs. You could be getting
• 57:05
  Speaker 1: a lot of junk bill and not even know it.
• 57:08
  Speaker 1: That sounds like a good situation actually, but it's there, Daniel,
• 57:13
  Speaker 1: it's clearing up your background and so I have questions.
• 57:16
  Speaker 1: That's right, there's a huge pile in your backyard. You
• 57:18
  Speaker 1: just haven't cleaned that part of it. All right. Well,
• 57:20
  Speaker 1: we hope you enjoyed that. Thanks for joining us, see
• 57:22
  Speaker 1: you next time. Thanks for listening, and remember that Daniel
• 57:33
  Speaker 1: and Jorge explained the Universe is a production of I
• 57:35
  Speaker 1: heart Radio. For more podcast from my heart Radio, visit
• 57:39
  Speaker 1: the i heart Radio app, Apple Podcasts, or wherever you
• 57:43
  Speaker 1: listen to your favorite shows. Yeah.