Speaker 1: Hey, Jorge, do you think that our culture might be
Speaker 1: devaluing the word super?
Speaker 2: I think our culture is sadly devaluing a lot of things.
Speaker 2: I hadn't really thought about the word super though.
Speaker 1: You know, you hear it super often. It's kind of
Speaker 1: like super everywhere, and after a while you super start
Speaker 1: to not even notice it.
Speaker 2: Yeah, I guess you're right. Are superheroes, super villains, super califragilistic, xpialidoses?
Speaker 2: It's used a lot.
Speaker 1: Maybe we should like limit how much we use it
Speaker 1: before it loses all of its power.
Speaker 2: Do you think we're gonna run out of words?
Speaker 1: We're gonna have to go to super duper, super extra duper.
Speaker 1: It's gonna get exhausting, or we're.
Speaker 2: Going to go to super conducting super colliders.
Speaker 1: All right, I admit scientists are guilty of this as well,
Speaker 1: but that's super duper not my fault.
Speaker 2: That's not a super excuse.
Speaker 1: There.
Speaker 2: I am hooreham May, cartoonists and the creator of PhD comics.
Speaker 1: Hi, I'm Daniel. I'm a particle physicist and a professor
Speaker 1: at UC Irvine, and I super duper love science.
Speaker 2: But what does that mean? I mean you love it
Speaker 2: in a super way, or you love it a lot.
Speaker 1: I guess it also means I kind of love super science.
Speaker 1: I love those projects that are big and grandiose that
Speaker 1: just put you at awe at what humans can do,
Speaker 1: what their minds can imagine, and what their hands can build.
Speaker 2: Well, the problem is you never know who those projects
Speaker 2: really are. You know, by day they're just mild mannered
Speaker 2: physics projects, but by night they take off their glasses,
Speaker 2: they put under cows and become superphysics.
Speaker 1: So the super conducting super Collider by day was just
Speaker 1: the normal, everyday conducting collider.
Speaker 2: And then it had a physics accident. I guess which
Speaker 2: gave it superpowers. That makes no sense. You superphysics become
Speaker 2: super heroid.
Speaker 1: Maybe you just put glasses on your normal, everyday conducting
Speaker 1: collider and it becomes a super collider.
Speaker 2: Oh no, no, the glass that makes you every day
Speaker 2: an every day person.
Speaker 1: Oh right, right, that's right. Take the glasses off the collider.
Speaker 2: Yeah, that's the issue, that's right, the fake glasses. We
Speaker 2: know lenses in them.
Speaker 1: Well, if we take all the lenses out of the
Speaker 1: large Hadron collider, I'm not convinced it's going to become
Speaker 1: a super large Hadron Collider.
Speaker 2: It's going to be super fun, though. What's going to happen?
Speaker 2: It's going to leap over tall buildings and or destroy
Speaker 2: tall buildings.
Speaker 1: Discover new particles in a single bound.
Speaker 2: But anyways, welcome to our podcast Daniel and Jorge Explain
Speaker 2: the Universe, a production of iHeartRadio.
Speaker 1: In which we delve into the super fascinating mysteries of
Speaker 1: the universe. How does it all work? Is it possible
Speaker 1: to make sense of this incredible dizzy and cosmos, all
Speaker 1: of its wonderful tiny particles and enormous swirling black holes,
Speaker 1: This incredible project that humans have been on for thousands
Speaker 1: of years to try to digest this incredible universe and
Speaker 1: translate it into a story that we can tell ourselves
Speaker 1: and explain to our children and make sense of.
Speaker 2: Yeah, because it is a pretty super universe, full of
Speaker 2: amazing demonstrations of power and abilities, and incredible particles and
Speaker 2: incredible stars and objects out there in space.
Speaker 1: And we want to understand all of it. Sometimes the
Speaker 1: answers to deep questions about the universe are right under
Speaker 1: our feet in the everyday physics that's going on around us.
Speaker 1: But other times we can find clues to how the
Speaker 1: universe works from the most dramatic, the most amazing, the
Speaker 1: most explosive situations out there.
Speaker 2: I fail. You're trying to find out what the real
Speaker 2: identity of the universe is. So do you think the
Speaker 2: universe wants its privacy, it's trying to protect its secrets.
Speaker 1: I do not believe in the privacy of the universe. Basically,
Speaker 1: physics is trying to unveil or undress the universe.
Speaker 2: Boy, you make it's some kind of RACYO super racy.
Speaker 1: Depends what's underneath that veil. I suppose if it's just equations,
Speaker 1: then it's very safe for work.
Speaker 2: It sounds like work. Actually that crazy at all.
Speaker 1: Actually, that's literally my job is to try to reveal
Speaker 1: the safer work equations that underpin the whole workings of
Speaker 1: the universe. Everything that's happening out there, we imagine can
Speaker 1: be described with mathematical formula and scientific thinking, or at
Speaker 1: least so far that's always worked.
Speaker 2: Yeah, because there is a lot to discover and a
Speaker 2: lot that we have seen about the universe out there.
Speaker 2: There are a lot of bright things out there for
Speaker 2: us to see and to study and to kind of
Speaker 2: parse the light to figure out what's going on out there.
Speaker 1: And we'd like to understand the whole universe, not just
Speaker 1: the part that's here under our feet, also the things
Speaker 1: that are very far out there in space. But those
Speaker 1: things present a special challenge, of course, because they're not
Speaker 1: right here for us to study. Instead, all we can
Speaker 1: do is examine the messages that they send us, the
Speaker 1: particles that be in clues to us from those distant objects.
Speaker 2: Yeah, and thank goodness that they are sending a signals
Speaker 2: through light, because otherwise we'd be living in a dark
Speaker 2: universe and have no idea what's going on out there
Speaker 2: beyond our Solar system.
Speaker 1: And in fact, we are probably living in a dark universe.
Speaker 1: Most of the stuff that's out there in the universe
Speaker 1: isn't sending us photons or any other kind of particles
Speaker 1: to give us clues about what it is and what
Speaker 1: it's doing. The dark matter that's out there holding galaxies
Speaker 1: together is stubbornly invisible to all of our senses and
Speaker 1: all of our telescopes is sending us messages, and those
Speaker 1: are not very subtle. It is screaming messages at us.
Speaker 1: It is blinding us with the incredible power of the
Speaker 1: photons that it creates.
Speaker 2: You make it sound like the universe is not a superhero,
Speaker 2: but maybe it's a super villain.
Speaker 1: Mm exactly. Maybe that's why it's evading our ability to
Speaker 1: understand it so far.
Speaker 2: It's a dark universe. It's a dark superuniverse.
Speaker 1: Well, you know, the story of science would be a
Speaker 1: lot more boring if the universe was more helpful. If
Speaker 1: it was just like, all right, look, humans, sit down
Speaker 1: for an hour. I'm gonna explain all this to you,
Speaker 1: then we would have been done thousands of years ago.
Speaker 2: Right, that sounds like a great story. I would be like,
Speaker 2: what why say universe being helpful? That's going on?
Speaker 1: It's a much more interesting story when there are twists
Speaker 1: and turns in dramatic revelations like a thousand years in Right,
Speaker 1: We're like on season five thousand of Science and we
Speaker 1: are still discovering incredible plot twists. Right, So, like no
Speaker 1: writer's room could have invented that.
Speaker 2: It's like a new genre of Netflix shows. P dramas,
Speaker 2: not K dramas or T dramas. It's physics dramas.
Speaker 1: The universe is the greatest story ever told, But.
Speaker 2: There are a lot of interesting signals coming to us
Speaker 2: from the universe out there. As you said, some of
Speaker 2: them are really bright. Some of them are super bright.
Speaker 1: And you know about stars and galaxies and black holes
Speaker 1: and even very bright events like supernova. But there are
Speaker 1: some things in the universe that are even brighter than
Speaker 1: your typical supernova. So today on the podcast, we'll be
Speaker 1: tackling the question what is a super luminous supernova. I'm
Speaker 1: guessing it's super but is it super duper only when
Speaker 1: it takes off its glasses? But this is what I
Speaker 1: was wondering about, Like, this thing has two supers in
Speaker 1: its name. It's not just a luminous nova. It's not
Speaker 1: just a luminous supernova. It's not a super luminous nova.
Speaker 1: It's a super luminous supernova. Oh my gosh.
Speaker 2: It's almost like you're making things up as you go along,
Speaker 2: like a three year old.
Speaker 1: Almost like we need somebody to tell us how to
Speaker 1: organize the naming of things in the universe.
Speaker 2: It's almost like physicis nitith thesaurus perhaps to look up
Speaker 2: synonyms for super I mean, I think there are a
Speaker 2: couple out there that you could have used that basically
Speaker 2: say the same thing.
Speaker 1: Mmmm, the super luminous extra nova, the hyper luminous supernova,
Speaker 1: those kind of things.
Speaker 2: Yeah, the uber luminous supernova, the extremely luminous sounds like
Speaker 2: you need a superhero called mister Thesaurus to rescue the
Speaker 2: day at the university there.
Speaker 1: The super thesaurus supernova.
Speaker 2: You're right. It is sort of like like there was
Speaker 2: a nova, and then there was a supernova, and then
Speaker 2: there was a luminous supernova, and then they found something
Speaker 2: even brighter. I'm guessing that they had to call a
Speaker 2: superluminous supernovas.
Speaker 1: Where are they going to go next? Right? The double
Speaker 1: superluminous supernova.
Speaker 2: Well, I guess you would have to find some other
Speaker 2: property of it, like maybe size, like supersize superluminous supernova.
Speaker 1: That sounds like you're ordering a second helping of fries,
Speaker 1: you know, Can I supersize my supernova? Please?
Speaker 3: No?
Speaker 2: Can I supersize my superluminous supernova? They're like, what do
Speaker 2: you think this is? Burger king? Get out of here.
Speaker 1: Only two supers per order, please, sir.
Speaker 2: But yeah, I'm guessing it is like an upgraded supernova.
Speaker 2: That's what I'm guessing what it is.
Speaker 1: It is something like that, and yet it contains deep
Speaker 1: mysteries that we do not yet understand well.
Speaker 2: As usual, we were wondering how many people out there
Speaker 2: had thought about what a superluminous supernova is or have
Speaker 2: any idea what it is.
Speaker 1: So thanks very much to everybody who answers these questions
Speaker 1: for our fun segment of the podcast, which used to
Speaker 1: be Person on the Street and is now a random
Speaker 1: person on the Internet. If you are a person on
Speaker 1: the Internet and you would like to participate in the future,
Speaker 1: please write to me too, question at Danielandjorge dot com.
Speaker 2: So think about it for a second. What do you
Speaker 2: think is a superluminous supernova? He would beeple had to say.
Speaker 4: My best guess would be that it's a supernova that,
Speaker 4: for some reason, perhaps do to excess energy input or
Speaker 4: some initial conditions that are extraordinary, produces way more electromagnetic
Speaker 4: radiation than a normal supernova.
Speaker 3: A super luminous supernova is probably a supernova that is
Speaker 3: extremely bright past the normal brightness that a supernova has.
Speaker 3: That would mean it would be an extremely bright supernova
Speaker 3: because the regular ones are already pretty bright.
Speaker 5: Superluminous supernova must be a supernova that just has high
Speaker 5: visual magnitude. Super super bright. Maybe we use it to
Speaker 5: measure distances.
Speaker 1: Well. The name seems to suggest that it's a supernova
Speaker 1: that emits more radiation than a regular super nova. Why
Speaker 1: that might be the case, I have no idea.
Speaker 6: I guess a super illuminous super and iva is in
Speaker 6: the name and that it's extra bright. But I thought
Speaker 6: a supernova I would say standard candle that people judge
Speaker 6: distances by. So maybe I'm being too simplistic.
Speaker 2: I think it's super illuminous supernova would be a supernova
Speaker 2: brighter than usual.
Speaker 1: Supernova's probably connected to the mouse.
Speaker 2: All right, I like the person who said it's in
Speaker 2: the name.
Speaker 1: You might almost say it's well named because it's communicated
Speaker 1: effectively what it is.
Speaker 2: I'm sure it's well named and that it communicates what
Speaker 2: it is. But you know, sometimes thesaurus comes in handy.
Speaker 2: For example, the same person said it means it extra bright.
Speaker 2: You could have just called it an extra bright supernova
Speaker 2: and then it wouldn't sound so sinsy.
Speaker 1: I don't know, it makes it sound more hollywoody. Maybe
Speaker 1: that's what they were going for, a.
Speaker 2: Little bit of glam super luminous supernova.
Speaker 1: Hmmm, it does have a certain ring to it.
Speaker 2: Well, step us through this interesting thing coming on, and
Speaker 2: let's start with the beginning. What is a supernova? Is
Speaker 2: it like a Noah that's super.
Speaker 1: It's like a nova that took off it's glasses.
Speaker 2: It's like a nova that's not an older Yeah.
Speaker 1: Actually the name comes from Kikobraje who wrote this book
Speaker 1: De Nova Stella, from which the word nova comes from
Speaker 1: nova there and means new as a new star because
Speaker 1: an observation of the changes in the sky. And so
Speaker 1: the supernova are one of these really cool astronomical objects
Speaker 1: because they happen sort of on human time scales. I mean,
Speaker 1: we're used to thinking about like stars forming and burning
Speaker 1: over millions and billions of years, and galaxies swarming for
Speaker 1: billions of years in the universe expanding over billions of years.
Speaker 1: Everything sort of happens on these really long time scales
Speaker 1: that we don't get to watch. We just have to
Speaker 1: like imagine and fast forward or in reverse. But supernova
Speaker 1: are really awesome because they're dramatic and they happen on
Speaker 1: human timescales, Like you can see this thing appear in
Speaker 1: the sky and then burn for a few weeks or
Speaker 1: months and then fade out. So the sky changes at
Speaker 1: a rate that we can actually see, which is why
Speaker 1: supernova are some of the oldest astronomical observations that we have.
Speaker 1: People have been seeing them and wondering what they were
Speaker 1: for literally thousands of years. And now we know, of
Speaker 1: course that supernova represent the endpoint of certain kinds of stars.
Speaker 1: Most stars don't end this way, but some stars end
Speaker 1: with this very dramatic collapse, this implosion, which then leads
Speaker 1: to very dramatic explosion and a huge release of energy.
Speaker 2: Wait, so you're saying it's the end point of a star,
Speaker 2: like the death of a star, and yet it's called
Speaker 2: the super nova, like a super new Well.
Speaker 1: It gets a little bit into what you mean by
Speaker 1: a star. But yeah, you have stars which are born
Speaker 1: and then burned and have fusion going on at their core,
Speaker 1: and there's this usual struggle between gravity that's compressing it
Speaker 1: and trying to make it more and more dense, and
Speaker 1: the fusion and the radiation that's puffing it out and
Speaker 1: keeping it from collapsing. But in the case of some supernova,
Speaker 1: eventually gravity wins, and we can walk through some of
Speaker 1: the mechanism for this, and you get this collapse where
Speaker 1: this shock wave propagates in very very fast crushes the
Speaker 1: star and then burns all of its fuel very very
Speaker 1: quickly and explodes. And so in a sense, that's the
Speaker 1: end point of the star and the birth of something
Speaker 1: new because you no longer have fusion happening.
Speaker 2: It sounds like a very political answer there.
Speaker 1: Well, you know, every death leads to a rebirth of
Speaker 1: some kind.
Speaker 2: All right, Well, it's like you said it, and it
Speaker 2: all starts with the collapse of a star. I think
Speaker 2: that's something that a lot of people don't know. Like,
Speaker 2: you know, we usually say a supernowa is the explosion
Speaker 2: of a star, But before the star explodes, it actually collapses, right.
Speaker 1: Yeah, And there's two ways that this can happen. The
Speaker 1: sort of classic way that we call core collapse is
Speaker 1: basically the end point of your standard solar fusion. You know,
Speaker 1: when a star starts out, it's mostly hydrogen. Sometimes it's
Speaker 1: a little bit of metal leftover from previous star burning.
Speaker 1: But you know, in the early universe it was all hydrogen.
Speaker 1: That hydrogen gas clumps together and falls together because of gravity,
Speaker 1: pushes it together, squeezes it together, gets it hot enough
Speaker 1: to have fusion, and then that fusion makes heavier stuff
Speaker 1: turns hydrogen into helium, and then helium into carbon, and
Speaker 1: carbon into oxygen and nitrogen and silicon. You get heavier
Speaker 1: and heavier stuff, until eventually it's made stuff that's so heavy,
Speaker 1: so massive that the gravity from its inner ashes, the
Speaker 1: product of its fusion, causes it to collapse. It can
Speaker 1: no longer hold off gravity, and so gravity eventually overcomes
Speaker 1: the outward pressure from fusion and the star collapses.
Speaker 2: Yeah. It's almost sort of like a phase transition, right,
Speaker 2: Like all of a sudden, the molecules inside of the
Speaker 2: Sun can't take the pressure, so they sort of collapse
Speaker 2: into a different arrangement, right, Like they're maybe staying apart
Speaker 2: from each other or staying at a certain density because
Speaker 2: of some forces. But then at some point those verses
Speaker 2: get overcome and the whole thing just kind of rearranges
Speaker 2: into a more compact form, right, something like that happens.
Speaker 1: Yeah, And it's very sudden. Right. Once it falls over
Speaker 1: the threshold is a runaway effect because gravit squeezes it
Speaker 1: and you get this shockwave inwards towards the core, which
Speaker 1: then bounces back out right. Because when the shockwave happens,
Speaker 1: now you've compressed the core. It's super duper high temperature,
Speaker 1: and now very quickly it does kinds of fusion that
Speaker 1: couldn't do before. It didn't used to be hot enough
Speaker 1: to make the heaviest of metals. But now in those
Speaker 1: brief moments during that shockwave, the conditions are right to
Speaker 1: make some of the really heavy metals, the ones you
Speaker 1: don't get during normal burning of the star. And then
Speaker 1: that fusion creates an incredible amount of radiation. So now
Speaker 1: the radiation wins. So it's sort of like a tug
Speaker 1: of war where it was balanced and then gravity starts
Speaker 1: to win. But then that creates the conditions for the
Speaker 1: pressure to take over again, and gravity loses and the
Speaker 1: star explodes.
Speaker 2: Yeah, it's sort of like a building collapsing. But then
Speaker 2: once the building collapses, that pressure of all that stuff
Speaker 2: being crushed together somehow unleashes other kinds of energy, right,
Speaker 2: and then the whole thing explodes. What's being unleashed is
Speaker 2: basically fusion energy, right.
Speaker 1: Yeah, what's being unleashed there is fusion energy exactly off
Speaker 1: and in kinds of fusion that you can't get during
Speaker 1: normal burning. And so that's one way that the universe
Speaker 1: makes super duper heavy metals like gold or uranium. Other
Speaker 1: methods are like collisions of neutron stars or other kinds
Speaker 1: of shock waves. It's very very hard to make those
Speaker 1: heavy elements because they require energy rather than producing it.
Speaker 2: That's kind of why they say some of these heavy
Speaker 2: elements like gold and some of the more complex elements
Speaker 2: are made in the heart of a dying star.
Speaker 1: Yeah, exactly, and so that's method number one. Basically for
Speaker 1: supernovas to form, it's actually called a type two supernova.
Speaker 1: This core collapse the other way similar, but it happens
Speaker 1: via a different path. Like you start out with a
Speaker 1: star that doesn't naturally have core collapse. It burns, it
Speaker 1: becomes a red giant as it puffs out and the hydrogen,
Speaker 1: helium and its atmosphere start to burn, a really big star.
Speaker 1: But then it doesn't turn into a supernova. Instead, it
Speaker 1: turns into a white dwarf, which is basically just leaving
Speaker 1: the hot core of the star, the metals that form
Speaker 1: during the initial burning. Everything else puffs out and the
Speaker 1: hot is left behind this white dwarf, And normally that
Speaker 1: white dwarf would just hang out for a long time
Speaker 1: and eventually over maybe like trillions of years would cool
Speaker 1: into a black dwarf. But if somebody comes along, like
Speaker 1: another star that's nearby, or it's part of a binary
Speaker 1: star system, it can eat a little bit more of
Speaker 1: that other star, which pushes it over the threshold for
Speaker 1: gravity to win and to cause a supernova. So it's
Speaker 1: sort of like a second act for this star. It
Speaker 1: gets enough fuel to cause this collapse and this supernova
Speaker 1: sort of later in the game.
Speaker 2: Right, that happens in like binary star systems, right, like
Speaker 2: a star system with two sons in them. But I
Speaker 2: guess my question is why do you need that extra step,
Speaker 2: Like why does it need to go in this particular way?
Speaker 2: Like why does one need to go into a white dwarf?
Speaker 2: And then the own has to get sucked in? What
Speaker 2: happens If the Sun's merged before that happens, would they
Speaker 2: still go supernova?
Speaker 1: If they merged before that happened, then they probably have
Speaker 1: enough mass. It's all about having enough mass. If you
Speaker 1: were big enough to begin with, then probably you would
Speaker 1: have ended up in a supernova. If you weren't big
Speaker 1: enough to begin with, if you were sort of a
Speaker 1: smaller star like our star, you just would have ended
Speaker 1: up with a white dwarf. And really it's all about
Speaker 1: the mass, because having more mass means having more gravity.
Speaker 1: Having less mass means having less gravity and not having
Speaker 1: enough force to overcome the structure of the star. I mean,
Speaker 1: to have this sort of collapse to have gravity trigger
Speaker 1: the supernova, you need enough gravity and resisting that is
Speaker 1: the structure of the star. A white dwarf has chemical
Speaker 1: bonds that are pushing out against this gravitational collapse. It's
Speaker 1: already a very dense object, but it's able to withstand
Speaker 1: the gravitational pressure. So you need an extra scoop, an
Speaker 1: extra helping of gravity to come over that threshold.
Speaker 2: I see. So it's really kind of mostly about just
Speaker 2: how much mass is out there or in that neighborhood.
Speaker 1: And type two supernova means you had enough mass originally
Speaker 1: to go supernova. Type one means you didn't and then
Speaker 1: you got an extra serving later which brought you over
Speaker 1: that threshold.
Speaker 2: Now, is it the case that any star that's bigger
Speaker 2: than this threshold is going to go supernova? Or at
Speaker 2: some point to do stars get too big to go supernova?
Speaker 1: Stars never get too big to go supernova. Basically, anything
Speaker 1: that's over like eight times the mass of the Sun
Speaker 1: is going to go red super giant and then type
Speaker 1: two supernova. Absolutely, there's really no way around that. That's
Speaker 1: just the fate of all these stars. But those stars
Speaker 1: are pretty rare, Like most of the stars in the
Speaker 1: universe are not that big. Even our star, which of
Speaker 1: course has one solar mass, is an unusually large and
Speaker 1: bright star in the universe. Most of the stars in
Speaker 1: the universe are smaller and cooler than our star. They
Speaker 1: are red dwarfs. So the number of stars in the
Speaker 1: universe that will go supernova is a small fraction. It's
Speaker 1: like a rare thing to happen.
Speaker 2: How rare is it? Like, is it super rare or
Speaker 2: just mild mannered rare.
Speaker 1: It's not something we know very accurately because we don't
Speaker 1: understand this initial mass function in the universe, the thing
Speaker 1: that determines like how much mass the stars get. But
Speaker 1: some calculations estimate it's like a few in a million stars.
Speaker 1: So you have a population of like a million stars,
Speaker 1: four or five of them might go supernova.
Speaker 2: Oh, only four, four or five are bigger than eight
Speaker 2: solar masses exactly.
Speaker 1: Yeah, it's really very dramatically dominated by the lower mass stars.
Speaker 2: And also I resented you said most stars are cooler
Speaker 2: than our son. I think our son is pretty cool.
Speaker 1: I think our son's pretty hot.
Speaker 2: Actually exactly, yeah, right, is.
Speaker 1: Our son hot or not? Yes, it's definitely hot.
Speaker 2: The answer is yes.
Speaker 1: That's a safer work answer.
Speaker 2: All right, Well, that's a super nova, and so let's
Speaker 2: dig into why they're hard to study, how we have
Speaker 2: studied them in the past, and then finally, what exactly
Speaker 2: is a super luminous supernova? So super stay with us,
Speaker 2: we'll be right back. All right, we're talking about superluminous
Speaker 2: supernova in a super way.
Speaker 1: And even a normal, non super luminous supernova is super nuper.
Speaker 1: It can be hard to appreciate, like how dramatic these
Speaker 1: events are, but a single supernova when it goes, can
Speaker 1: be brighter than the rest of the galaxy that it's in.
Speaker 1: These galaxies contain, you know, often hundreds of billions of stars.
Speaker 1: Now you have a single object brighter than hundreds of
Speaker 1: billions of stars. It's really an incredible event. And we're
Speaker 1: just talking about your ordinary garden variety supernova.
Speaker 2: Yeah, I know we've mentioned that before. Like when a
Speaker 2: star goes supernova's brighter than the galaxy. And but that
Speaker 2: sounds kind of crazy, like what does that mean. It
Speaker 2: means that it's outputting more light than all of the stars,
Speaker 2: the hundreds of billions of stars in that galaxy in
Speaker 2: that moment.
Speaker 1: Yeah, that's exactly what it means, and that's why we
Speaker 1: can see them. Right, Most of the supernova we have
Speaker 1: seen are in other galaxies. The Milky Way is kind
Speaker 1: of weirdly quiet in supernova. We haven't seen one in
Speaker 1: our galaxy in several centuries. So most of the supernova
Speaker 1: that we have seen are in other galaxies, and we
Speaker 1: can see them because they are brighter then the entire
Speaker 1: galaxy that they're in.
Speaker 2: Wait, you said that we haven't seen one in the
Speaker 2: Milky Way, but so we have seen super nova that
Speaker 2: have come from the Milky Way.
Speaker 1: We have seen supernova in the Milky Way. But the
Speaker 1: last person to do it was Kepler, like sixteen oh four, Kepler,
Speaker 1: he's got like the last paper on supernova's in the
Speaker 1: Milky Way. We haven't seen one from our own galaxy
Speaker 1: in four hundred years.
Speaker 2: But how did Kepler knowa was within our galaxy?
Speaker 1: Well, Kepler didn't really know because He didn't really understand
Speaker 1: the idea of galaxies. We didn't even know like that
Speaker 1: there were other galaxies back then. But we can now
Speaker 1: look at the thing he was studying, and we understand
Speaker 1: what he was looking at, and we know that it's
Speaker 1: in our galaxy.
Speaker 2: How do we know what he was looking at? Did
Speaker 2: he leave like a star map?
Speaker 1: Kepler was pretty good at taking records. That's why he
Speaker 1: and Tiko Brahe were one of the first ones to
Speaker 1: really understand stellar motion and planetary motion. They were pretty
Speaker 1: nerdy about it.
Speaker 2: M So, I guess, how do we know he looked
Speaker 2: at one in our milk way? Because it brightness or what?
Speaker 1: Again? We know which object he was looking at. He
Speaker 1: told us where it was in the sky. He has
Speaker 1: pretty detailed records of what he was looking at, so
Speaker 1: we can now look at that object like, what was that? Oh, look,
Speaker 1: it's a remnant from a supernova.
Speaker 2: Oh, we can see the remnant of it now.
Speaker 1: Yeah, And that's actually really valuable because we'd love to
Speaker 1: study these things over many centuries or many thousands of
Speaker 1: years to understand like what happens after supernova? How does
Speaker 1: the cloud disperse? It gives you a lot of clues
Speaker 1: about what was going on inside of it, something we
Speaker 1: still don't really understand. So studying something hundreds of years
Speaker 1: later is really valuable. And so having like ancient astronomical
Speaker 1: records that say, oh, there was a supernova here five
Speaker 1: hundred years ago or two thousand years ago is actually
Speaker 1: really relevant and powerful to astronomy today.
Speaker 2: Now, if a supernova has as much energy as the
Speaker 2: whole galaxy, wouldn't that just fry everything in the galaxy
Speaker 2: or at least in like the half of the galaxy
Speaker 2: it's in.
Speaker 1: Yes, supernova are very dangerous and very damaging potentially to life.
Speaker 1: So we should be glad that there haven't been like
Speaker 1: a whole rash of supernova in our neighborhood, because we
Speaker 1: might not be. Here's an enormous amount of radiation released
Speaker 1: in supernova, and it's very dramatic in the visible spectrum
Speaker 1: and the high energy photons like gamma rays, et cetera,
Speaker 1: which would be extraordinarily damaging to life on Earth. It
Speaker 1: turns out, though, actually most of the energy from a
Speaker 1: supernova isn't even in the visible light, like they're already
Speaker 1: as bright as the rest of the galaxy. But that's
Speaker 1: one percent of the energy released by the supernova, most
Speaker 1: of it is actually released in new trinos.
Speaker 2: Yeah, that's amazing. I think we've talked about that before.
Speaker 2: But why neutrinos, Like, why would it put all of
Speaker 2: its energy into something that can barely be felt.
Speaker 1: Well, I don't think there's like a committee there deciding,
Speaker 1: like how much do we budget in neutrinos versus photons.
Speaker 1: It's just sort of what the physics does. And for
Speaker 1: a long time we didn't understand how important neutrinos were
Speaker 1: because it feels like they're sort of irrelevant. Once energy
Speaker 1: turns into neutrinos, it feels like it can't really participate
Speaker 1: in physics anymore because most of the universe ignores neutrinos.
Speaker 1: Neutrinos are these particles that only feel the weak interaction,
Speaker 1: and they can fly through like a light year of
Speaker 1: lead without interacting with anything. So people thought for a
Speaker 1: long time, well, if you're dumping the energy into neutrinos,
Speaker 1: that's basically just lost. But more recent simulations of supernovas
Speaker 1: have discovered that those neutrinos actually do interact with the
Speaker 1: rest of the material. Rest of the material that's collapsing
Speaker 1: is so dense that it actually can absorb some of
Speaker 1: that heat back from neutrinos. So there's an amazing effect
Speaker 1: in supernova's called neutrino heating, where the neutrinos from the
Speaker 1: supernova actually reheat the material. And if you don't have
Speaker 1: this effect, then the explosion doesn't happen. So why is
Speaker 1: it produced. It's just because in fusion you get a
Speaker 1: lot of these nuclear processes. A lot of them just
Speaker 1: result in photons and neutrinos, but it turns out those
Speaker 1: neutrinos are really important for making the explosion happen.
Speaker 2: But somehow they're like the main product of whatever's happening
Speaker 2: in the supernova.
Speaker 1: Yeah, and it's not just supernovas, right, Stars in their
Speaker 1: normal course of business produce an enormal number of neutrinos.
Speaker 1: Like here on Earth there's one hundred billion neutrinos per
Speaker 1: square centimeter per second. Like you hold your hands out
Speaker 1: and there's a trillion neutrinos going through your fingernails every second.
Speaker 1: And we're really far away from the Sun, right, So
Speaker 1: imagine like how many neutrinos are produced in the Sun itself,
Speaker 1: And now supernova's produce like ten to the fifty eight
Speaker 1: neutrinos during their supernova explosion. So it's really an incredible
Speaker 1: amount of energy in neutrinos. So, yeah, supernovas are super
Speaker 1: duper bright and luminous, and that's a tiny fraction of
Speaker 1: the sort of true brightness of these incredible events.
Speaker 2: It's almost like it's a good thing it's making so
Speaker 2: many neutrinos. But it's a good thing it's putting all
Speaker 2: its energy into neutrinos, because if it put it into
Speaker 2: something that we would feel like every galaxy everywhere would
Speaker 2: be toast all the time.
Speaker 1: Right, Yeah, yeah, that's exactly right. We're lucky that they're
Speaker 1: exploding in this sort of safe way. And even still,
Speaker 1: they're very dangerous. If there were a super nova in
Speaker 1: our backyard, it would fry half of the Earth, or
Speaker 1: if it lasted long enough for the Earth to rotate,
Speaker 1: who basically fry the whole Earth.
Speaker 2: How far would a supernova need to be to be
Speaker 2: at a safe distance from us.
Speaker 1: That's a good question, and it depends a little bit
Speaker 1: on the brightness of the supernova. The type one supernova's
Speaker 1: the ones that start with binary stars there are st
Speaker 1: like ten times brighter than the core collapse supernovas because
Speaker 1: they're more dramatic, So it depends a little bit on
Speaker 1: the type. Anything in our stellar neighborhood at all would
Speaker 1: really fry us. So supernova's on the other side of
Speaker 1: the galaxy, no big deals. Supernova's on our side of
Speaker 1: the galaxy, you start to get a little bit nervous.
Speaker 1: Supernova's within a few tens of light years, we're toasted.
Speaker 2: Okay, so we're sort of safe. But I feel like
Speaker 2: you said that supernovas happen like a few every couple
Speaker 2: of million stars, and the milk Away has several hundred
Speaker 2: billion stars, right, so there should be, you know, thousands
Speaker 2: and thousands of them sprinkled all over the Milky Way
Speaker 2: potentially about to go off.
Speaker 1: There should be, and we don't understand it. And we
Speaker 1: did a whole podcast episode about the mystery of the
Speaker 1: missing Milky Way supernova. Go check that out. It's a
Speaker 1: really fun question about whether supernova's are happening in our
Speaker 1: galaxy but we can't see them because they're obscured by
Speaker 1: the center of the galaxy, or maybe there's something weird
Speaker 1: about our galaxy. Also, the supernova that had happened in
Speaker 1: the Milky way tend to be sort of weirdly distributed.
Speaker 1: They're not really in the place where most of the
Speaker 1: stars are, and so there's a lot of mysteries about
Speaker 1: why we haven't had more supernova in our galaxy. Check
Speaker 1: out that episode.
Speaker 2: Maybe it was Superman who pushed all those supernova away,
Speaker 2: or maybe another superhero or Superwoman.
Speaker 1: Yeah, it's really fun to read the sort of historical
Speaker 1: record here of like Chinese astronomers talking about guest stars
Speaker 1: that appear in the night sky. Hilariously, they describe them
Speaker 1: as some having pleasurable colors and others not having pleasurable colors.
Speaker 2: Way, there were so many happening somebody supernova happening that
Speaker 2: they could compare the colors.
Speaker 1: They just commented on them, because these things evolve over time,
Speaker 1: you know, they change in color. I thought it was
Speaker 1: just hilarious that they note not only did this incredible
Speaker 1: thing happen in the sky, but some of us didn't
Speaker 1: think it was very pretty.
Speaker 2: Some of us didn't think it was pretty, very super
Speaker 2: there were more kind of a met.
Speaker 1: Nova, or maybe they were just recording, you know, their
Speaker 1: anxiety about it, like, wow, this is a crazy thing
Speaker 1: to be happening in our sky. You don't usually see
Speaker 1: a lot of things changing. Eclipses and comets and supernova
Speaker 1: are like pretty dramatic events in the sky. It's fascinating
Speaker 1: to think about what it must have been like to
Speaker 1: be somebody seeing that happen and not understand it at all.
Speaker 1: It must have seemed very mystical.
Speaker 2: Well, you said, it's very rare to see a supernova, like,
Speaker 2: how many have we seen since recorded history?
Speaker 1: Well, we've only seen a handful in our galaxy. But
Speaker 1: because we now have incredible telescopes, we've seen hundreds and
Speaker 1: hundreds of supernova in other galaxy. But still it's limited
Speaker 1: to you know, like numbers like hundreds. We don't have
Speaker 1: thousands and thousands of these examples.
Speaker 2: Is it likely that I would see a supernoa go off?
Speaker 2: You know, first of all, I would have to be
Speaker 2: a whig all night, which I guess I am. But
Speaker 2: I'm looking at the sky. I am, Like, would I
Speaker 2: notice but supernova went off to light up the whole sky?
Speaker 2: Would it just kind of appear like, oh, there's a
Speaker 2: new pinpoint of light there.
Speaker 1: Well, a new supernova in our galaxy you could see
Speaker 1: with the naked eye. It would be like a new
Speaker 1: event in the sky, and it could be brighter than
Speaker 1: many other starts depending on how close it is. It
Speaker 1: could definitely brighten up the night sky. For sure. Most
Speaker 1: of the supernova we have observed are in other galaxies,
Speaker 1: and so they are brighter or as bright as that galaxy,
Speaker 1: which is still pretty dim to the naked eye, so
Speaker 1: easy to spot with telescopes. Not that easy to see
Speaker 1: with the naked eye, but potentially somebody could point you
Speaker 1: to one and say that's a supernova. That little dot.
Speaker 1: There is a distant galaxy with a supernova in it.
Speaker 2: I guess what I mean is like, you would have
Speaker 2: to know what this night sky looked like before the
Speaker 2: supernova in order to be like, oh, that's something new
Speaker 2: there that you couldn't see before with the telescope.
Speaker 1: Yeah, exactly. And that's basically what we do is we
Speaker 1: scan the sky and we look for changes or always
Speaker 1: on the lookout for these supernova because they're hard to predict.
Speaker 1: We can't very easily look at a bunch of stars
Speaker 1: and say that one's going to go supernova, and that
Speaker 1: one's going to do supernova tomorrow or Tuesday. We have
Speaker 1: to just catch them happening. So we're constantly scanning the sky,
Speaker 1: comparing it to what the sky looked like yesterday and
Speaker 1: last week, looking for changes, and as soon as somebody
Speaker 1: spots one, then a bunch of telescopes get trained on
Speaker 1: it to track it in great detail to understand its
Speaker 1: light curve. Because remember that's like really valuable information for
Speaker 1: understanding how far away is that galaxy, which tells us
Speaker 1: things about like the expansion of the universe. Really incredible
Speaker 1: scientific discoveries are pinned on capturing these supernova inaction.
Speaker 2: Wonder if that's stressful for astrophysicists, you know, like I
Speaker 2: can't go to the bathroom, go get coffee, because what
Speaker 2: if supernova comes up just as I'm leaving my desk.
Speaker 1: It is sometimes very dramatic.
Speaker 3: You know.
Speaker 1: We have automated systems that scan for these things, but
Speaker 1: once you see one, then they get communicated to other
Speaker 1: telescopes around the world which might have been busy doing
Speaker 1: something else, and then decide, you know what, this is
Speaker 1: more important. We're going to change our observation plan. We're
Speaker 1: going to turn around and look at this crazy thing
Speaker 1: that's happening because it might only last for a few days.
Speaker 2: And you said they're sort of unpredictable. I guess they're
Speaker 2: not unpredictable in the sense that I mean, you can
Speaker 2: tell if a star is going to go supernova at
Speaker 2: some point, right, you said all stars above us certain size,
Speaker 2: do you just don't know when it's going to happen.
Speaker 1: Yeah, I think that's true. We can't look at a
Speaker 1: star and say this is about to go supernova, or
Speaker 1: that's about to go supernova. And some stars don't actually explode,
Speaker 1: like they collapse. They have the first part of it,
Speaker 1: but then they don't bounce back and have an explosion.
Speaker 1: And there's all sorts of different kinds of ways that
Speaker 1: these stars can collapse, and sometimes there's a black hole
Speaker 1: that's created at the heart and sometimes not, and so
Speaker 1: they can look very different from collapse to collapse. So
Speaker 1: while all these stars that are big enough will eventually
Speaker 1: burn out their fuel and collapse, they don't all trigger
Speaker 1: exactly the same kind of supernova. Some of them kind
Speaker 1: of whiff out, some of them get very bright. And
Speaker 1: that's a lot of what we don't understand. And the
Speaker 1: reason we don't understand it is that it's very complicated physics.
Speaker 1: You have a lot of things going on here. You
Speaker 1: have general relativity that describes the gravitational pull, and you
Speaker 1: have very complicated fluid dynamics to describe like how the
Speaker 1: pressure is propagated through this thing. Plus you have fusion happening,
Speaker 1: so you have radiation coming outwards. You have neutrinos, which
Speaker 1: turn out to be important. So it's one of these scenarios.
Speaker 1: We have to get a lot of the details right
Speaker 1: in order to make the prediction accurate. And we're just
Speaker 1: very recently able to even like simulate these things and
Speaker 1: see supernova happen on the computers.
Speaker 2: Sounds like you need another category for them, like super confusing,
Speaker 2: super lubinus supernovas. Maybe we just need supercomputers, yeah, or
Speaker 2: maybe you need Superman to come in and do some physics.
Speaker 2: I think I need a super grand to understand supernovas
Speaker 2: with a super big pile of money. It sounds like
Speaker 2: you're getting super greedy. They're super villain.
Speaker 1: I just want to understand the universe. Is that so greedy?
Speaker 2: Well, all supervillains think they're doing the right thing. All right.
Speaker 2: It's a deep dive into how we study supernovas. Let's
Speaker 2: get into what a super luminous supernova is and whether
Speaker 2: or not it is super or not. But first, let's
Speaker 2: take a quick break. All right, we're talking about super
Speaker 2: luminous supernovas, which I guess means just the super bright supernovas.
Speaker 1: It does mean super bright supernovas, though we sort of
Speaker 1: run out of modifiers here because already supernovas are super
Speaker 1: bright events and super rare events. They're like very dramatic
Speaker 1: moments in this story of the universe. But then we
Speaker 1: saw some supernova that were so ridiculously bright even by
Speaker 1: the standards of supernova, that they had to come up
Speaker 1: with another category for them. So super luminous supernova are
Speaker 1: supernova that are at least ten times brighter than your normal,
Speaker 1: run of the mill incredibly bright supernova.
Speaker 2: Whoa first of all, ten times brighter, that's amazing. And second,
Speaker 2: see you just used another word, incredibly bright. You don't
Speaker 2: have to use super again.
Speaker 1: You're right, we should call them incredibly bright.
Speaker 2: It's supernova amazingly bright, extra right.
Speaker 1: Overwhelmingly bright supernova.
Speaker 2: Now let's go with super luminous. That sounds cooler or hotter.
Speaker 1: But there's something else going on here, which is this
Speaker 1: astronomical need to like categorize, because in one sense like
Speaker 1: you make a distribution of all the supernova some are brighter,
Speaker 1: some are dimmer. Whatever you expect them to not all
Speaker 1: be the same, and so why can't you just say, well, look,
Speaker 1: here's supernova summer brighter, some are dimmer. But this need
Speaker 1: to name this extra bright category comes out of this
Speaker 1: like feeling like something different is happening. It's not just
Speaker 1: that there's a distribution and these are the ones on
Speaker 1: the tail. They feel like they see this cluster, this
Speaker 1: collection of supernova that are different from the other ones.
Speaker 1: It's like this grouping on the very high side where
Speaker 1: they think maybe something different is happening.
Speaker 2: Oh, that's interesting. So there's a range of brightness for supernovas,
Speaker 2: and typically I thought all supernovas, we're all sort of
Speaker 2: the same. That's how they use as standard markers in
Speaker 2: the universe.
Speaker 1: So the type one A supernova, the ones that are
Speaker 1: super bright already, they're not all the same brightness. Actually,
Speaker 1: they have all the same shape of their light curve,
Speaker 1: which means how they get bright and then how they
Speaker 1: dim which then you can calibrate to how bright they
Speaker 1: are actually at their source through a few steps. So
Speaker 1: it's not quite as simple as all these supernovas are
Speaker 1: exactly the same brightness always. It's that you can deduce
Speaker 1: how bright they are by how quickly they ramp up
Speaker 1: and how quickly they ramp down. It's sort of like
Speaker 1: remember the cephids, those variable stars, the ones that get
Speaker 1: brighter and dimmer and brighter and dimmer. It's not that
Speaker 1: they're all the same brightness, it's that from the period
Speaker 1: of their pulsation, you can deduce how bright they are.
Speaker 1: It's sort of that way for type one A supernova.
Speaker 1: They're not all the same brightness, but you can figure
Speaker 1: out how bright they are from their curve.
Speaker 2: So you have these super or extra brightnd supernovas that
Speaker 2: are ten times brighter than regular supernovas, But then you
Speaker 2: have some that are ten times even brighter than that exactly.
Speaker 1: So you got the type twos the sort of like
Speaker 1: normal supernovas, and then type one A are ten times
Speaker 1: brighter than that.
Speaker 2: So they're super luminous supernova.
Speaker 1: And then and then the extra right supernova extralous supernova.
Speaker 1: These are ten times brighter than even those.
Speaker 2: You might as well say super super humanous.
Speaker 1: Super squared supernova. And these things are super nuper right,
Speaker 1: and they're also really rare, like one in ten thousand supernova,
Speaker 1: which is already like, you know, five out of a
Speaker 1: million stars, So now we're talking about like five out
Speaker 1: of ten billion stars are going to be super luminous supernova.
Speaker 1: These are incredibly rare. Wow.
Speaker 2: So that means that their brightness is ten times brighter
Speaker 2: than the galaxy they're in over regular galaxy.
Speaker 1: Yeah, they can outshine their galaxy by huge amount, and
Speaker 1: not just because they're extra bright, but weirdly, for reasons
Speaker 1: we don't understand, they tend to be found in smaller,
Speaker 1: dimmer galaxies. So we talked recently on the podcast about
Speaker 1: these things called dwarf galaxies, galaxies with a small or
Speaker 1: a number of stars in them, and how they're fascinating
Speaker 1: laboratory for understanding maybe the formation of the universe and
Speaker 1: how galaxies form and dark matter. But these superluminous supernova
Speaker 1: tend to be found only in these dwarf galaxies, which
Speaker 1: is like a weird clue maybe about why they happen
Speaker 1: and what makes them super luminous, But it also means
Speaker 1: that they're extra bright compared to their galaxies, which tend
Speaker 1: to be extra dimm That.
Speaker 2: Is a weird clue, right. A dwarf galaxy, as we
Speaker 2: talked about before, is just kind of a small galaxy,
Speaker 2: but it's also sort of made up of different kinds
Speaker 2: of stars too.
Speaker 1: Yeah, dwarf galaxy just means a smaller blob of stars.
Speaker 1: It can be like thousands to just a few billion stars.
Speaker 1: It's a pretty big range. Remember that our galaxy is
Speaker 1: like one hundred billion or two hundred billion stars, So
Speaker 1: dwarf galaxy is a much much smaller galaxy. But there's
Speaker 1: a really wide range of these things. Some of them
Speaker 1: are like mostly dark matter and have just a few
Speaker 1: sprinkling of stars. Others have had their dark matter stripped
Speaker 1: out of them. Some of them are like early progenitor galaxies.
Speaker 1: We think that the big galaxies came from the combination
Speaker 1: of a bunch of dwarf galaxies. So some of these
Speaker 1: dwarf galaxies might be sort of like primordial and as
Speaker 1: you say, could have like older stars from the earlier
Speaker 1: part of the universe.
Speaker 2: All right, So then what's making these super super superluminous supernovas.
Speaker 1: We don't know. It's a mystery something we see in
Speaker 1: the universe but do not yet understand. We have like
Speaker 1: no model that tells us why this can be happening.
Speaker 1: I remember, we just barely understand why supernovas go boom
Speaker 1: and what's going on inside of them and how all
Speaker 1: that radiation happens. You know, when we write down all
Speaker 1: of our physics and code it in the computer, we
Speaker 1: can barely get it to happen in simulation, and maybe
Speaker 1: in those simulations line up with what we see in
Speaker 1: the universe. But there are a few ideas for what
Speaker 1: might make it happen, and they come from noticing how
Speaker 1: these are different from the other supernoas, not just in
Speaker 1: their brightness, but in other characteristics.
Speaker 2: Well, I guess, first of all, do we know why
Speaker 2: some supernovas are brighter than others? Is it just about
Speaker 2: how much size they have, how much mass was there
Speaker 2: when they collapse?
Speaker 1: We don't really understand. It has to do with all
Speaker 1: the internal dynamics and how much energy is devoted to
Speaker 1: photons and whether the object itself is transparent enough to
Speaker 1: release those photons or if it's going to be opaque
Speaker 1: and reabsorb those photons. So it's a complicated thing that
Speaker 1: we do not understand very well right now, and.
Speaker 2: It doesn't have to do with the size, like I
Speaker 2: would imagine like a bigger star if it collapses, would
Speaker 2: make a bigger explosion than a small star that collapses.
Speaker 1: It's definitely part of the equation, right, The more energy
Speaker 1: you have, the more energy you can convert into radiation.
Speaker 1: It's definitely part of that equation. But it's not quite
Speaker 1: so simple, right. It's not just like bigger star, brighter supernova.
Speaker 1: But you might be on the right track because one
Speaker 1: suspicion is that these superluminous supernova come from stars that
Speaker 1: are unusually large stars that have more than forty times
Speaker 1: our Sun's mass when they start out, and that's very
Speaker 1: unusually large for a star. So that's one suspicion is
Speaker 1: that maybe they come from the heaviest of heavy stars.
Speaker 2: And what makes us think that just from the idea
Speaker 2: that bigger is brighter.
Speaker 1: It's just like one of the things. It's just like
Speaker 1: one explanation, as you say, more mass means you have
Speaker 1: more energy that you can convert into light. So it's
Speaker 1: just like a starting point. There are a few other
Speaker 1: interesting clues that point in that same direction, like the
Speaker 1: light from these stars is a little bit different from
Speaker 1: light from other supernova. They don't seem to have a
Speaker 1: lot of helium or hydrogen in their outer atmosphere. Remember,
Speaker 1: you can tell what's in a star by looking at
Speaker 1: the light that it emits, because helium and hydrogen and
Speaker 1: all the elements have their own characteristic ladder of energy
Speaker 1: levels that the electrons are allowed to be around them,
Speaker 1: which means when the electrons jump down an energy level
Speaker 1: or release a photon, you can kind of tell which
Speaker 1: kind of atom it came from by looking at the
Speaker 1: energy of that photon, which has to line up with
Speaker 1: the spacing of the energy levels of that atom. So
Speaker 1: you can look at the spectrum from a star and
Speaker 1: you say, oh, look, there's a peak here that means
Speaker 1: there was hydrogen, or there's a dip here that means
Speaker 1: there was helium that was absorbing that light. So from
Speaker 1: the peaks and the dips in the emission of the
Speaker 1: star specs you can tell what it's made out of.
Speaker 1: What they've noticed is that these stars when they go
Speaker 1: tend to have almost no hydrogen a no helium in them,
Speaker 1: which is pretty unusual. Most stars when they go supernova
Speaker 1: still have helium and hydrogen like in the outer layer
Speaker 1: that hasn't been burnt yet.
Speaker 2: But these don't put that mean that they're older stars
Speaker 2: maybe or more mature stars.
Speaker 1: It could be, or it could be that something else
Speaker 1: is going on nearby that's like strip them of their atmosphere.
Speaker 1: Maybe there's a very strong solar wind, or there's a
Speaker 1: binary star that's been gobbling up their atmosphere, or maybe
Speaker 1: they're one of these weird kind of stars called a
Speaker 1: wolf rayet star that do tend to have very little
Speaker 1: hydrogen and helium in them because as you say, they've
Speaker 1: burned it already. That feels like an important clue. That's
Speaker 1: one thing that makes these things different. But we don't
Speaker 1: understand why not having hydrogen and not having helium would
Speaker 1: make the explosion brighter. Like if you take a star
Speaker 1: and you remove it's hydrogen helium, why would that give
Speaker 1: you a brighter supernova? We don't understand, or maybe that's
Speaker 1: not the answer. Maybe there's some other reason that generates
Speaker 1: a bright supernova and happens to also remove the hydrogen
Speaker 1: and helium from the star. It's just like a clue
Speaker 1: we have found. We don't understand it yet.
Speaker 2: Now have we seen any Are there any special superluminous
Speaker 2: supernova that we've seen that are sort of interesting to
Speaker 2: talk about.
Speaker 1: The most dramatic one is really incredible. It's this supernova
Speaker 1: called ASASSN, which is the name of the telescope fifteen
Speaker 1: LH and it's about four billion light years away. But
Speaker 1: when we saw it in twenty fifteen using these twin
Speaker 1: telescopes in Chile, it was the most luminous supernova ever observed.
Speaker 1: It was almost a trillion times brighter than our sun.
Speaker 2: A trillion times brighter than the Sun. Yeah, that's wild.
Speaker 2: It's a good thing. It wasn't in our doubts.
Speaker 1: Yeah, there's this astronomer from Ohio State University, christof Stenek
Speaker 1: said if it was in our own galaxy, it would
Speaker 1: shine brighter than the full moon. There would re no
Speaker 1: night it would be easily seen during the day. Like,
Speaker 1: this thing was a monster. It's more than two times
Speaker 1: brighter than any other superluminous supernova.
Speaker 5: Whoa.
Speaker 2: And it was sort of a kind of luck that
Speaker 2: we caught it right.
Speaker 1: Absolutely, it's lucky. We just like happened to be pointing
Speaker 1: telescopes in the right direction at the right time, and
Speaker 1: that's why we saw it. But it's also sort of
Speaker 1: hard to miss. Like, this thing is twenty times brighter
Speaker 1: than our higher galaxy. It's really amazing. So this was
Speaker 1: definitely the brightest supernova ever.
Speaker 2: But it's also kind of far away. That's why it's
Speaker 2: easy to miss.
Speaker 1: Yeah, it's four billion light years away, otherwise it might
Speaker 1: have fried us.
Speaker 2: It's like a tensive the way to the end of
Speaker 2: the universe.
Speaker 1: Yeah, exactly, So pack some snacks if you're going to
Speaker 1: go visit.
Speaker 2: But it's cool. We could see it from here, right,
Speaker 2: and it's so bright even for me so far away.
Speaker 1: It is really cool, and it offers an opportunity to
Speaker 1: like think about what's going on and understand how supernova's form.
Speaker 3: You know.
Speaker 1: One idea about what makes these things so bright is
Speaker 1: that they're just like super big versions of stars that
Speaker 1: make super luminous supernova. Maybe they're just bigger and they're
Speaker 1: more massive and that's what's happening. But there are also
Speaker 1: other theories, like maybe these are other kinds of events,
Speaker 1: they're not just bigger versions of supernova. Like maybe there's
Speaker 1: an interplay between these stars and black holes that are
Speaker 1: nearby that are triggering a different kind of collapse.
Speaker 2: Yeah, Like if you see something bright in the sky
Speaker 2: doesn't necessarily have to be a supernova, right, it could
Speaker 2: be something else exploding, or maybe like a quasar or
Speaker 2: something like that.
Speaker 1: Yeah, although these things have the sort of pretty characteristic
Speaker 1: light curve of a supernova and they appear briefly and
Speaker 1: then disappear, which quasars don't. But black holes might be contributing.
Speaker 1: Like maybe you have a star that was going to
Speaker 1: go supernova anyway, and the tidal forces from a nearby
Speaker 1: black hole add to the collapse and like make that
Speaker 1: collapse more powerful. Right, if you're near like a supermassive
Speaker 1: black hole in the center of your galaxy, it could
Speaker 1: be that the tidal forces from that trigger the collapse
Speaker 1: in a way that wouldn't have happened otherwise you get
Speaker 1: like a special version or an unusual version of the collapse.
Speaker 2: Wait, so this would be a super massive black holes supercharged,
Speaker 2: superluminous supernova. Is that what you're telling me? It would
Speaker 2: be pretty incredible, extra extra bright exactly.
Speaker 1: That's one alternative idea. Another really cool idea that's reading
Speaker 1: about is that it could be magnetars losing their energy. Right,
Speaker 1: maybe it's not a supernova at all. A magnetar is
Speaker 1: a neutron star, which is another potential endpoint for a
Speaker 1: star that's spinning really really fast and has a huge
Speaker 1: magnetic field and all sorts of incredible energy, But they're
Speaker 1: dumping a lot of that energy out into space. They're
Speaker 1: converting their rotational energy into this beam. And so the
Speaker 1: idea is maybe one of these magnetars has a dramatic
Speaker 1: spin down effect where it's transforming its rotational energy very
Speaker 1: suddenly into a bunch of radiation, which creates these huge
Speaker 1: jets and produces enough energy to look like a superluminous supernova.
Speaker 1: But people have tried to do calculations to make that happen,
Speaker 1: and they don't think that those things could be bright
Speaker 1: enough to explain what we've seen. So it's still sort
Speaker 1: of a wild West of ideas out there, people wondering like,
Speaker 1: maybe it's this, maybe it's that. Maybe it's these two
Speaker 1: things combined that makes this crazy event.
Speaker 2: I guess if it's something so bright and so explosive,
Speaker 2: wouldn't we sort of see evidence of that explosion affecting
Speaker 2: the whole galaxy it's in, or a lot of the
Speaker 2: stars it's in. You know, maybe that way you could
Speaker 2: tell if it's an explosion after all or not, it is.
Speaker 1: Actually really cool to track these explosions. You feel like
Speaker 1: it's going to affect the whole galaxy. But remember that
Speaker 1: galaxies are really big, and so for information to get
Speaker 1: across the galaxy takes a long time. So these explosions
Speaker 1: look sort of like they're happening in slow motion because
Speaker 1: the distances are just so vast, Which is one reason
Speaker 1: why it's really cool to look at old supernova to
Speaker 1: see how has the supernova affected stuff nearby, Like when
Speaker 1: the supernova radiation slams into nearby gas, what happens. Do
Speaker 1: you generate new stars? Do you heat it up? Do
Speaker 1: you blow it out? That's one reason why it's really
Speaker 1: cool to look at these sort of old supernovas from
Speaker 1: the past.
Speaker 2: Yeah, like I would maybe imagine like at the side
Speaker 2: of where there was a supernova, maybe like all the
Speaker 2: stars around it got snuffed out or something re a
Speaker 2: least pushed out of the way or something. At least
Speaker 2: that's how it looks like in movies. In superhero movies,
Speaker 2: well you do.
Speaker 1: Get this very dramatic and I think very pleasing to
Speaker 1: the eye clouds of gas and shock waves that come
Speaker 1: out of supernova. Some of the prettiest nebula that are
Speaker 1: out there, like the crab Nebula, actually did come from
Speaker 1: ancient supernova. It was in the nineteen forties we realized
Speaker 1: that the crab nebula is the remnant of a supernova
Speaker 1: that the Chinese saw about a thousand years ago. So
Speaker 1: we get to watch like a thousand years of slow
Speaker 1: mo explosion playing out in the sky.
Speaker 2: So we're not even true if it is a supernova.
Speaker 2: These super luminous events, yeah.
Speaker 1: That's true. There's still a bunch of different theories about
Speaker 1: what could be causing them, and eventually we might even
Speaker 1: give them a different name. We might even drop the super.
Speaker 2: Yeah, or maybe a super luminous supernova might try it
Speaker 2: to be just a mild mannered black hole explosion or.
Speaker 1: Something like that. You never know what happens when they
Speaker 1: take off their glasses.
Speaker 2: All right, Well, another amazing excuse to look at the
Speaker 2: night sky each night. If you're looking at the night
Speaker 2: sky and you look up at the start, maybe you'll
Speaker 2: catch a supernova one day. Right, It's totally possible, isn't it.
Speaker 1: It's totally possible, And here's hoping that supernova is not
Speaker 1: so close that it super fries your super eyeballs.
Speaker 2: Yeah, it might be the last thing you see unfortunately
Speaker 2: in the night sky.
Speaker 1: And for everything that we have learned already about the universe,
Speaker 1: remember that we are still learning new things. It was
Speaker 1: only a couple of decades ago that we first identified
Speaker 1: super luminous supernova, these very incredibly rare things. So there
Speaker 1: could be things happening out there in the universe that
Speaker 1: are so rare. We just haven't seen one yet. And
Speaker 1: maybe somebody out there will be the first person to
Speaker 1: see this new super event.
Speaker 2: Yeah, and then you can give it a good name,
Speaker 2: an incredible name, an amazing name, an extra special name,
Speaker 2: a hyper name, while avoiding hyperbole of course, exactly. All right, Well,
Speaker 2: we hope you enjoyed that. Thanks for joining us, See
Speaker 2: you next time.
Speaker 1: Thanks for listening, and remember that Daniel and Jorge Explain
Speaker 1: the Universe is a production of iHeartRadio. For more podcasts
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