The Extreme Universe with Tim Paglione

What can gamma rays tell us about supernovae and galaxy formation? Neil deGrasse Tyson and co-host Chuck Nice sit down with astrophysicist Tim Paglione to explore high-energy cosmic phenomena, gamma rays, and the extreme events that create them.

Speaker names marked ? are inferred from speaking time and the show’s known hosts — they are not voice-verified.

• 0:00Speaker 00

  That particle shower, these extensive air showers, they'll come flying in and those muons will stream down to the surface, a thousand just went through your body.

• 0:08Neil deGrasse Tyson?

  Wow.

• 0:09Speaker 00

  Another, another thousand.

• 0:11Neil deGrasse Tyson?

  Oh.

• 0:12Speaker 00

  Another thousand. But the interesting thing is their, their lifetime is so short that they shouldn't make it.

• 0:21Neil deGrasse Tyson?

  Welcome to StarTalk, your place in the universe where science and pop culture collide. StarTalk begins right now. This is StarTalk. Neil deGrasse Tyson, your personal astrophysicist. We've got a cosmic queries lined up for you, and that means I got Chuck Nice in the house. That's right. What's up Neil? All right, good. Feeling good. Good. You know, I'm mining my colleagues once again. Sounds illegal. Tim Paglione. Tim, how you doing, man?

• 0:57Speaker 00

  All right.

• 0:58Neil deGrasse Tyson?

  Welcome to StarTalk, your first time.

• 0:59Speaker 00

  Thanks, yeah.

• 1:00Neil deGrasse Tyson?

  And we've known each other how long?

• 1:01Speaker 00

  Probably like 20 years.

• 1:02Neil deGrasse Tyson?

  Man, welcome.

• 1:04Speaker 00

  Thank you.

• 1:05Neil deGrasse Tyson?

  To the show. Fellow astrophysicist, you're a professor at the City University of New York. Nice. At the Graduate College.

• 1:13Speaker 00

  Excellent.

• 1:14Neil deGrasse Tyson?

  And at York.

• 1:15Speaker 00

  Yep.

• 1:16Neil deGrasse Tyson?

  College, one of the campuses of the CUNY system. And we have AstroCom here, and what is AstroCom short for?

• 1:24Speaker 00

  So, full name's AstroCom NYC, and the Astro, the Com, and AstroCom is community. So it's all about building community.

• 1:31Neil deGrasse Tyson?

  Okay, and you mentor students within that community?

• 1:34Speaker 00

  Yep, it's been 74.

• 1:36Neil deGrasse Tyson?

  74 students?

• 1:37Speaker 00

  Yeah, we've been going for a dozen years now.

• 1:40Neil deGrasse Tyson?

  Yeah, because it's not good enough just to be a scientist if you just, you know, live on an island.

• 1:44Speaker 00

  Right.

• 1:45Neil deGrasse Tyson?

  You gotta pass the torch at some point. Let's hope. Share the torch. Yeah, that's a good island. Yes. Where scientists are actually bringing up other scientists. Right, they don't vote you off the island. Yeah, they don't vote you off the island. They bring you into the island. Yeah, unless you say you believe in astrology, then they're like, you gotta get out. No, a good educator will then show them why that's an error. But let's be honest. Let's just be honest here.

• 2:07Speaker 00

  Then you vote them off.

• 2:11Neil deGrasse Tyson?

  So, one of the reasons why we have you here is you've done a lot of thinking and a lot of observing and a lot of publishing about extreme objects in the universe. And people love them, some extreme things. Everybody loves extremes. We love it. So you go big or you go home. Yes.

• 2:28Speaker 00

  Yeah, super fun. That's the stuff.

• 2:29Neil deGrasse Tyson?

  Yeah, so as we ascend the electromagnetic spectrum in energy, and we go red, orange, yellow, green, blue, violet.

• 2:39Speaker 00

  You skipped.

• 2:40Neil deGrasse Tyson?

  I skipped indigo, because indigo doesn't belong there. That's Isaac Newton being mystically fascinated by. You broke up Bell-Biv-Devoe.

• 2:50Speaker 00

  I don't think that was his name.

• 2:52Neil deGrasse Tyson?

  Roy G. Biv, not Bell-Biv-Devoe. Roy G. Biv, right. So violet and then ultraviolet, which can give you skin cancer. And then X-rays, which will give you organ cancer. And now gamma rays. That turn you into the Hulk.

• 3:11Speaker 00

  They go right through you.

• 3:13Neil deGrasse Tyson?

  So tell me about what makes gamma rays in the universe? Because we know stars make regular light. And we also know black holes in their vicinity, they can heat up the gases and they'll radiate ultraviolet and X-rays. But gamma rays seem to just come from their own places.

• 3:29Speaker 00

  Yeah, it's the most energetic light that there is, so you need a really super energetic process. So you have to blow stump them up, or have a huge shock run through an area to accelerate particles to nearly the speed of light.

• 3:43Neil deGrasse Tyson?

  Shock means something very specific in astrophysics, so tell us about that. Because otherwise, shock, what does shock mean anywhere? Oh dear.

• 3:53Neil deGrasse Tyson?

  That's not what we mean. Did you see what that black hole did? You were shocked by the shock.

• 4:01Speaker 00

  So, I mean, simply put, in a certain area, there's a speed of sound. And if you go beyond that, that's a shock.

• 4:09Neil deGrasse Tyson?

  You make a shock.

• 4:10Speaker 00

  Yeah, yeah.

• 4:12Neil deGrasse Tyson?

  Just go beyond it, like, so you need a process that will overtake something as fast as the speed of sound in that medium.

• 4:19Speaker 00

  That's right. So like an explosion, if a star explodes, it's a supernova, it'll send a shock wave out through the interstellar medium.

• 4:25Neil deGrasse Tyson?

  Mm-hmm.

• 4:25Speaker 00

  And that'll bunch up all the gas into high density, it'll bunch up all the magnetic fields.

• 4:30Chuck Nice?

  So, so let me ask you this.

• 4:31Speaker 00

  Yeah.

• 4:31Chuck Nice?

  When you look at...

• 4:32Neil deGrasse Tyson?

  Wasn't he in the middle of explaining something?

• 4:34Chuck Nice?

  No, it's cool. That was, okay, so, in the medium itself, all right, air is the medium through which the shock wave of sound travels, right?

• 4:44Speaker 00

  Sound that we...

• 4:45Chuck Nice?

  The sound that we...

• 4:46Speaker 00

  Yeah, that we're doing right now.

• 4:47Neil deGrasse Tyson?

  Here on Earth.

• 4:47Chuck Nice?

  Here on Earth.

• 4:48Speaker 00

  Hmm.

• 4:48Chuck Nice?

  So in space, if it's a vacuum, what exactly is the shock traveling on?

• 4:54Neil deGrasse Tyson?

  Good question.

• 4:55Speaker 00

  Yeah, there's always a little bit of something going on out there.

• 4:58Chuck Nice?

  Oh.

• 4:58Speaker 00

  Yeah, and so anytime there's any kind of discontinuity, it, it, we would also describe as a shock. And the things that I'm most interested that'll create gamma rays, these high energy, high energy particles called cosmic rays.

• 5:12Chuck Nice?

  Mm-hmm.

• 5:13Speaker 00

  They're accelerated by these bunched up, shocked up magnetic fields.

• 5:16Chuck Nice?

  Okay, there you go.

• 5:17Neil deGrasse Tyson?

  Shocked up, that's a, that's a statement.

• 5:20Speaker 00

  That is a made up phrase.

• 5:21Neil deGrasse Tyson?

  Shocked up, just like, you jacked, I'm shocked.

• 5:24Chuck Nice?

  Yeah, I'm shocked up, baby.

• 5:25Speaker 00

  Exactly.

• 5:26Chuck Nice?

  Tell you right now.

• 5:27Neil deGrasse Tyson?

  All right, so in that one sentence, you, you mentioned gamma rays.

• 5:31Speaker 00

  Mm-hmm.

• 5:31Neil deGrasse Tyson?

  And cosmic rays, and shock waves.

• 5:34Speaker 00

  Yeah.

• 5:35Neil deGrasse Tyson?

  Right, all of this. And this is high energy phenomenon is where you're coming from here. So what's your best way to create high energy phenomenon? I know we can do it in the lab, in the accelerators.

• 5:46Speaker 00

  Yeah, yeah.

• 5:47Neil deGrasse Tyson?

  So, does our understanding of the acceler, in the accelerator, help us in what, in your job?

• 5:52Speaker 00

  Actually, it really does. So, once we had the Large Hadron Collider going.

• 5:57Neil deGrasse Tyson?

  Mm-hmm, in Switzerland, the CERN.

• 5:59Chuck Nice?

  CERN.

• 6:00Neil deGrasse Tyson?

  Yeah, mm-hmm.

• 6:00Speaker 00

  So from the rates of, you know, the bajillions of collisions that they're doing there, uh, we were able to figure out the, the, basically the interaction rate of, of protons at those high energies, and that, that made, actually, my models of those proton-proton collisions in the interstellar medium, a little more accurate, uh, which was kind of nice. But we work at way higher energies.

• 6:22Neil deGrasse Tyson?

  Than, we, I mean, the universe.

• 6:24Speaker 00

  The universe.

• 6:25Neil deGrasse Tyson?

  Yeah.

• 6:25Speaker 00

  He's taking credit for the universe. That is the super mega royal we.

• 6:29Neil deGrasse Tyson?

  My people, my stars, my, yeah, it's the royal we if there ever was one.

• 6:32Speaker 00

  Exactly.

• 6:33Neil deGrasse Tyson?

  And so, so you're accelerating protons to much higher energies than even the most powerful accelerators on Earth.

• 6:40Speaker 00

  Yeah, that's right.

• 6:41Neil deGrasse Tyson?

  Okay, and now they're fast moving, can a single proton make a shock wave? No, right? What, what goes on there?

• 6:48Speaker 00

  No.

• 6:49Neil deGrasse Tyson?

  You need a wave of them, I mean, a bunch of them.

• 6:51Speaker 00

  Yeah, you need a bunch of them, and, but as long as they find another proton out there, like an ambient proton, which is just a hydrogen atom.

• 6:57Neil deGrasse Tyson?

  Ambien, ambient proton.

• 6:59Speaker 00

  Right.

• 6:59Neil deGrasse Tyson?

  Yeah, these are the sleepy ones.

• 7:02Neil deGrasse Tyson?

  The one's not looking.

• 7:03Speaker 00

  Ambient.

• 7:04Neil deGrasse Tyson?

  Ambient, okay.

• 7:06Speaker 00

  So if there's just an interstellar cloud out there, it's just hydrogen minding its own business.

• 7:10Chuck Nice?

  Just hanging out.

• 7:11Speaker 00

  Gets whacked by one of these high-energy protons, that'll create a bunch of other particles. It's a nuclear reaction, and just like you'd get at the particle accelerators, and all these things come out, these pions come out. Some are positively charged, some are negative.

• 7:25Neil deGrasse Tyson?

  So they call those daughter products.

• 7:26Speaker 00

  Sure.

• 7:27Neil deGrasse Tyson?

  But never son products, I always wondered.

• 7:30Chuck Nice?

  Daughters very rarely disappoint. Sons often do.

• 7:34Speaker 00

  I wonder if it was Marie Curie that did that.

• 7:36Chuck Nice?

  Ooh, that makes sense.

• 7:38Neil deGrasse Tyson?

  Interesting.

• 7:39Chuck Nice?

  So cool if it was.

• 7:40Speaker 00

  It would be.

• 7:41Chuck Nice?

  Yeah.

• 7:42Neil deGrasse Tyson?

  It's dateable to that point in time, right?

• 7:45Speaker 00

  Oh, for sure.

• 7:45Neil deGrasse Tyson?

  Because that's when we see the.

• 7:47Speaker 00

  The first person to see the X-rays, yeah. That's where the alpha, beta, and gamma rays were first named.

• 7:51Neil deGrasse Tyson?

  Yeah.

• 7:52Speaker 00

  When we didn't know what they were, that's just the first three letters of the Greek alphabet.

• 7:55Chuck Nice?

  Makes sense.

• 7:56Speaker 00

  Yeah.

• 7:56Neil deGrasse Tyson?

  So they were just some source of energy moving out of your experiment into somewhere else. So an alpha rays became what? What did we discover those to be?

• 8:03Speaker 00

  Those are helium nuclei.

• 8:05Neil deGrasse Tyson?

  Yeah, that's kind of weird, but all right. The nucleus of a helium atom, alpha rays, okay? We just call them rays, because we didn't know, because we can't, we couldn't distinguish the energy of a wave from the energy of a particle. Those idiots.

• 8:20Neil deGrasse Tyson?

  Okay, alpha, beta.

• 8:21Speaker 00

  Turned out to be electrons.

• 8:22Neil deGrasse Tyson?

  Just electrons. Just electrons. We go from the helium nucleus. Right. To electrons. Mm-hmm. See, that ain't right. That's right. That's wild.

• 8:30Speaker 00

  They had a really interesting result, though, because they had a whole bunch of different energies of electrons of beta rays would come out. And that led Enrico Fermi to say, there must be something else carrying this extra energy. And that turned out to be some little tiny massless particle with no charge, which is a neutrino. Neutrino. It was little.

• 8:48Neil deGrasse Tyson?

  Right.

• 8:49Speaker 00

  It was a little one.

• 8:50Neil deGrasse Tyson?

  Which, yeah. The eno. The eno makes it little. And neutra is neutral. Right, right. So there was, the energy budget was not resolved.

• 8:58Speaker 00

  That's right.

• 8:58Neil deGrasse Tyson?

  That's in the.

• 8:59Speaker 00

  There was always some leftover.

• 9:00Neil deGrasse Tyson?

  So, yeah, okay. So is that the residual, the neutrino itself?

• 9:04Speaker 00

  Yeah.

• 9:04Neil deGrasse Tyson?

  Yes, that's a, that's a, that's a gangster prediction. That's badass. Right. If you say we're missing energy, therefore, there's a particle with no charge that carried it away that we didn't detect. That's. That's like making shit up.

• 9:15Speaker 00

  Totally.

• 9:16Neil deGrasse Tyson?

  Just to fill in the blank.

• 9:17Speaker 00

  Yeah.

• 9:17Neil deGrasse Tyson?

  And it turned out to be exactly the case.

• 9:19Speaker 00

  Oh, yeah, for sure.

• 9:20Neil deGrasse Tyson?

  That's wild.

• 9:20Speaker 00

  Mm-hmm.

• 9:21Neil deGrasse Tyson?

  Wow, that's very cool, man.

• 9:23Speaker 00

  It is.

• 9:24Neil deGrasse Tyson?

  All right, so now tell me, the proton hits what to then make a shower of other particles? Another proton?

• 9:30Speaker 00

  Another proton, yeah.

• 9:31Neil deGrasse Tyson?

  Okay, and so it busted open the proton?

• 9:34Speaker 00

  Mm-hmm.

• 9:34Neil deGrasse Tyson?

  And what I, my classical knowledge of nuclear physics ends with the quarks that are inside.

• 9:40Speaker 00

  Yeah.

• 9:40Neil deGrasse Tyson?

  But I guess you can pair up quarks and make particles that are not protons but are lighter than protons?

• 9:47Speaker 00

  Yeah, yeah, so, well, pair them up, yes.

• 9:49Neil deGrasse Tyson?

  I guess, I don't know.

• 9:50Speaker 00

  Yeah, so, I mean, from this reaction, from the proton-proton interaction, you end up, primarily you get muons, oh, you'll get some pions, primarily pions are the ones that interest me the most. There's, there's positive ones, negative ones, and neutral ones. The neutral ones with no charge, they immediately decay into two gamma rays, which is usually what we see.

• 10:09Neil deGrasse Tyson?

  So there's a whole chart of what's going on there that you need to be fluent in, otherwise you don't know what the hell is going on. Yeah, kinda.

• 10:19Neil deGrasse Tyson?

  Okay, remind us about muons, because I'm fascinated that they exist at all.

• 10:23Speaker 00

  Yeah, because they're, they're very short-lived, and so this is one of these interesting-

• 10:27Neil deGrasse Tyson?

  But can you quantify that, short-lived?

• 10:29Speaker 00

  Can I quantify that?

• 10:30Neil deGrasse Tyson?

  I mean, short-lived, a few seconds, a few microseconds?

• 10:33Speaker 00

  Way smaller, way, way faster.

• 10:34Neil deGrasse Tyson?

  Even shorter than that, okay.

• 10:36Speaker 00

  In fact, the time it takes a muon to reach the surface of the Earth from space, from, from the atmosphere, where they're created by these cosmic rays hitting the atmosphere, they shouldn't live to get to the surface. Travelling at almost the speed of light, they shouldn't make it, and yet they do. And this was one-

• 10:55Neil deGrasse Tyson?

  They sort of decayed before that.

• 10:56Speaker 00

  Yeah, I was gonna say, they're, yeah, okay. But the trick is that they're travelling so fast that their clock's at a different speed than ours.

• 11:01Chuck Nice?

  Oh, that's amazing!

• 11:03Neil deGrasse Tyson?

  Ain't that some stuff? So you have muons in your exotic places in the universe? But I hear that we also detect muons here on Earth?

• 11:11Speaker 00

  Oh, yeah.

• 11:11Neil deGrasse Tyson?

  So what's going on there?

• 11:12Speaker 00

  So you'll get one of these energetic cosmic rays will come in and hit something in our atmosphere.

• 11:17Neil deGrasse Tyson?

  So it's the same phenomenon?

• 11:18Speaker 00

  Exactly the same. Right. Yeah, in fact-

• 11:20Neil deGrasse Tyson?

  But that's happening to us?

• 11:20Speaker 00

  The Earth's atmosphere is a bright, bright gamma ray background, in fact. So, um, that particle shower, these extensive air showers.

• 11:28Neil deGrasse Tyson?

  Because it busted open the proton, okay?

• 11:30Speaker 00

  They'll, they'll come flying in, and those muons will stream down to the surface. A thousand just went through your body.

• 11:36Chuck Nice?

  Wow.

• 11:37Speaker 00

  Another, another thousand.

• 11:39Chuck Nice?

  Oh!

• 11:41Neil deGrasse Tyson?

  Another thousand.

• 11:43Speaker 00

  But the interesting thing is, their, their lifetime is so short that they shouldn't make it. That trip from the top of the atmosphere down to here, they should decay before that. They should decay before they hit the Earth.

• 11:53Neil deGrasse Tyson?

  Long before they hit the Earth.

• 11:55Speaker 00

  Then why do they make it? Well, because they're travelling so fast that their clock is running at a different speed than ours. That's amazing. So they actually don't know any better?

• 12:06Neil deGrasse Tyson?

  So Einstein was right. So it's relative, time dilation?

• 12:10Speaker 00

  Is that time dilation? Right here on Earth, it's a...

• 12:15Chuck Nice?

  You've gotta love science, people. You just gotta love it.

• 12:18Speaker 00

  Yeah, can't argue with that.

• 12:20Neil deGrasse Tyson?

  He blows a gasket every now and then. You gotta love. You gotta recover from that.

• 12:23Chuck Nice?

  So phenomenal.

• 12:24Neil deGrasse Tyson?

  And muons, they behave like electrons, right?

• 12:27Speaker 00

  Yeah, yeah, except there could be positive ones too. Well, they're different.

• 12:34Neil deGrasse Tyson?

  Thank you, Professor Baglio.

• 12:36Speaker 00

  They're fundamentally different. I mean, they've got mass. They're not a fundamental particle like an electron, things like that.

• 12:42Neil deGrasse Tyson?

  But they're analogous to an electron, and why?

• 12:45Speaker 00

  Yeah, well, there are muons with negative charges. Electrons have negative charges. But if you leave a muon alone, it'll decay, and you can get an electron from that. So, in a way, you could think that an electron's kind of hidden inside a muon.

• 13:00Chuck Nice?

  Okay. That's weird.

• 13:03Speaker 00

  Yeah.

• 13:05Neil deGrasse Tyson?

  Okay, all right. So these energetic phenomena, I think, because we're colleagues and I hear, the most energetic things I know of are supernovae. And then there's hypernovae. What are those things, hypernovae?

• 13:19Speaker 00

  That would just be a big-ass explosion. I don't really know. There are supernovae that are just extremely energetic. They're hard to explain.

• 13:28Neil deGrasse Tyson?

  Bad-ass supernovae.

• 13:29Speaker 00

  Yeah, you're right near the edge there.

• 13:31Chuck Nice?

  Is there a quantifiable magnitude of nova, supernova, hypernova, like, that we would be able to understand as a regular person?

• 13:40Neil deGrasse Tyson?

  You're not a regular person. Let's get that straight.

• 13:44Chuck Nice?

  Like, yeah, you know what I mean?

• 13:45Neil deGrasse Tyson?

  We have a hierarchy of words, and how do they correspond to hierarchies of energy? Is that what you're trying to say?

• 13:50Chuck Nice?

  Yes, what I'm trying to say. Like, how would you explain, like, okay, so a nova is like, 10 nuclear bombs, or 5 hydrogen bombs, or whatever, just so that we could, like...

• 13:59Speaker 00

  I wish I had that number, but I think it's more of those bombs than I could put that number to.

• 14:05Chuck Nice?

  More than we could ever imagine. More bombs you can imagine.

• 14:09Speaker 00

  I mean, you get 10 to the 53 ergs from what we call a type 2 supernova explosion, so that's a massive star that'll explode and end up as a black hole.

• 14:18Chuck Nice?

  Right.

• 14:18Speaker 00

  And that's like a factor of 10 to the 20 more than a nova, just a little, a little...

• 14:23Chuck Nice?

  10 to the 20 more?

• 14:24Speaker 00

  Yeah, yeah, it's a huge difference in energy.

• 14:27Neil deGrasse Tyson?

  In that explosion, correct me if I'm wrong, it's emitting more energy... than all the stars in the galaxy in which it explodes.

• 14:35Speaker 00

  Yeah, that's something, I mean.

• 14:36Neil deGrasse Tyson?

  I think that's right. If the sun is 10 to the 33 ergs per second, and it's 10 to the 53 total ergs.

• 14:42Speaker 00

  Yeah.

• 14:43Neil deGrasse Tyson?

  So that's 10 to the 20th more ergs.

• 14:47Speaker 00

  The, the, the one that I've heard is if you add up all the energy that the sun will ever emit in its all, in its total lifetime, that's like a supernova.

• 14:55Neil deGrasse Tyson?

  That's a supernova.

• 14:55Speaker 00

  Yeah.

• 14:56Neil deGrasse Tyson?

  Gotcha. Right.

• 14:57Speaker 00

  It's huge.

• 14:57Neil deGrasse Tyson?

  Yeah, that's almost the same way to think about the same problem. So all in, all at once. All at once. You're looking at 10 billion, 15 billion years

• 15:04Speaker 00

  Yeah.

• 15:05Neil deGrasse Tyson?

  of radiation all at once.

• 15:08Speaker 00

  Yep.

• 15:08Neil deGrasse Tyson?

  And, and that's why, so they're visible across the universe.

• 15:21Speaker 03

  I'm Kais from Bangladesh and I support StarTalk on Patreon. This is StarTalk with Neil deGrasse Tyson.

• 15:35Neil deGrasse Tyson?

  So how far away are your objects? Are they all in our own galaxy?

• 15:38Speaker 00

  Everything that I've been studying lately has been in our own galaxy, but I've also studied other galaxies. But nearby ones, mostly. But now I've just started getting into galaxy clusters. Um, but still nearby clusters.

• 15:50Neil deGrasse Tyson?

  Okay.

• 15:50Speaker 00

  But they're getting kind of far away now.

• 15:52Neil deGrasse Tyson?

  Let's just take a moment as we record this

• 15:55Speaker 00

  Mm-hmm.

• 15:55Neil deGrasse Tyson?

  in the year 2024.

• 15:57Speaker 00

  Yes.

• 15:57Neil deGrasse Tyson?

  That 100 years ago.

• 15:58Speaker 00

  Yes.

• 15:59Neil deGrasse Tyson?

  Hubble, the man, not the telescope, discovered that we're not alone as a galaxy in the universe.

• 16:06Speaker 00

  Wow.

• 16:06Neil deGrasse Tyson?

  Yeah.

• 16:07Speaker 00

  Ended the great debate.

• 16:09Neil deGrasse Tyson?

  No, he didn't do the debate.

• 16:10Speaker 00

  No, he ended it.

• 16:11Neil deGrasse Tyson?

  Ended it. He ended the great debate. Okay, the great debate was, are the spiral nebulae just local phenomena in our own galaxy?

• 16:18Speaker 00

  Right.

• 16:19Neil deGrasse Tyson?

  Or they whole other

• 16:20Speaker 00

  Whole other galaxies.

• 16:20Neil deGrasse Tyson?

  Whole other galaxies out there like ours.

• 16:23Speaker 00

  Yeah.

• 16:23Neil deGrasse Tyson?

  Island universes. And now, now we know there's a whole trillion of them out there. Yeah, yeah.

• 16:26Speaker 00

  Yeah.

• 16:27Neil deGrasse Tyson?

  That's amazing. They got out of control. Look at that. So you mentioned Emiko Fermi just a moment ago

• 16:32Speaker 00

  Hmm.

• 16:32Neil deGrasse Tyson?

  as the

• 16:33Speaker 00

  The neutrino.

• 16:34Neil deGrasse Tyson?

  The nu, was he the namer of the neutrino?

• 16:35Speaker 00

  I believe so.

• 16:36Neil deGrasse Tyson?

  He must have been Italian.

• 16:37Speaker 00

  Yeah.

• 16:37Neil deGrasse Tyson?

  And neutrino. Makes sense, yeah. That's exactly how he said it too.

• 16:41Chuck Nice?

  I believe I have a discovery. It's got a neutrino.

• 16:45Neil deGrasse Tyson?

  That's Chuck speaking Italian.

• 16:47Speaker 00

  There you go.

• 16:47Chuck Nice?

  By the way, that's yeah, that's every American who's not Italian, speaking Italian.

• 16:51Neil deGrasse Tyson?

  And if they were girl neutrinos, they'd be neutrinos.

• 16:53Chuck Nice?

  Ooh.

• 16:53Neil deGrasse Tyson?

  Right, wouldn't they?

• 16:54Chuck Nice?

  That's very cool.

• 16:55Neil deGrasse Tyson?

  Yeah.

• 16:55Chuck Nice?

  Now I'm interested.

• 16:59Neil deGrasse Tyson?

  So, we tend to name telescopes after scientists or other people relevant to our field. And I read recently about the Fermi Telescope. And I don't know anything about it. Could you catch me up on it?

• 17:10Speaker 00

  Yeah, so it's a gamma ray, it's the Fermi Gamma Ray Space Telescope.

• 17:14Neil deGrasse Tyson?

  A space telescope?

• 17:15Speaker 00

  Yeah. You gotta be in space because gamma rays will interact with the earth's atmosphere, so...

• 17:20Neil deGrasse Tyson?

  And give you muons.

• 17:21Speaker 00

  Yeah, yeah, and pions and the whole gamut.

• 17:24Chuck Nice?

  Yeah, yeah.

• 17:24Speaker 00

  Yeah, good stuff. Uh, so it's in space.

• 17:27Neil deGrasse Tyson?

  Is this the first gamma ray telescope, space telescope?

• 17:29Speaker 00

  It is not. Uh, so its predecessor was the Compton Gamma Ray Observatory.

• 17:34Neil deGrasse Tyson?

  I knew that, okay.

• 17:35Speaker 00

  It's the size of a bus. It was a really big one.

• 17:37Neil deGrasse Tyson?

  Cause that, it's a bus that fits inside the space shuttle.

• 17:40Speaker 00

  Yeah.

• 17:40Neil deGrasse Tyson?

  So...

• 17:41Speaker 00

  Just.

• 17:41Neil deGrasse Tyson?

  Yeah, so, it's not that it just fit in, it's designed to just fit.

• 17:47Speaker 00

  Oh, for sure.

• 17:48Neil deGrasse Tyson?

  That's your size, just make it fit.

• 17:50Chuck Nice?

  Yeah, there's, that's your whole payload.

• 17:51Neil deGrasse Tyson?

  That's the whole, that's the whole payload, yeah.

• 17:53Chuck Nice?

  Right there, yeah.

• 17:54Speaker 00

  At the time, and it may still hold the record, it was the heaviest thing that the shuttle ever launched.

• 17:58Neil deGrasse Tyson?

  Really?

• 17:58Speaker 00

  Yeah.

• 17:59Chuck Nice?

  Wow.

• 17:59Neil deGrasse Tyson?

  Okay.

• 18:00Speaker 00

  But you need a heavy detector like that to stop the gamma rays, you know, to detect them. It's, it's in essence, the Fermi Gamma Ray Space Telescope is a particle detector.

• 18:08Chuck Nice?

  Okay.

• 18:08Neil deGrasse Tyson?

  But it could also know what direction it's coming from.

• 18:10Speaker 00

  That's right, yeah. So, it, it detects when a photon comes in, and it's one photon at a time.

• 18:16Neil deGrasse Tyson?

  Gamma ray photon.

• 18:16Speaker 00

  Yeah. So, one pho-, when the photon comes in, uh, where it came from as best as it can.

• 18:22Neil deGrasse Tyson?

  You're counting one photon at a time?

• 18:24Speaker 00

  One at a time.

• 18:25Chuck Nice?

  That's insane.

• 18:26Speaker 00

  They're rare. It's, this is the highest energy stuff. You need, you need something special to create it. And so, yeah, they're pretty rare.

• 18:33Neil deGrasse Tyson?

  Man, they're just, just...

• 18:35Speaker 00

  Dishing them out.

• 18:35Neil deGrasse Tyson?

  Just, here, here, one for you, man.

• 18:37Chuck Nice?

  One for you, one for you. We got a photon, guys.

• 18:41Speaker 00

  Guys?

• 18:42Neil deGrasse Tyson?

  And, and looking over here, let me toss one to those, to those aliens.

• 18:47Speaker 00

  That's pretty wild, man.

• 18:47Neil deGrasse Tyson?

  I mean, when you talk to solar astronomers.

• 18:50Speaker 00

  Oh, gosh.

• 18:50Neil deGrasse Tyson?

  You can't even have a conversation.

• 18:51Speaker 00

  Yeah.

• 18:52Neil deGrasse Tyson?

  Because they have like countless photons coming from the sun.

• 18:56Speaker 00

  Even us, just from anything, from a star, you get countless photons, you know, so these, these, it's, they're precious, one photon at a time.

• 19:03Neil deGrasse Tyson?

  Okay. So what will it do that the Compton Observatory couldn't do?

• 19:08Speaker 00

  Fermi was a great improvement on that localization, like figuring out what the direction was. Uh, so it could pinpoint the direction of the gamma ray much better. That was really important.

• 19:17Neil deGrasse Tyson?

  Because I think there, there's whole generations of detectors where they just detect something.

• 19:21Speaker 00

  Hmm, right.

• 19:22Neil deGrasse Tyson?

  And with no information as where it came from, it just detected it.

• 19:26Speaker 00

  Just right.

• 19:27Neil deGrasse Tyson?

  Right?

• 19:27Speaker 00

  And it was even worse with, with, with Compton because the, you, you would really like to say, oh, we detected a gamma ray from this crazy source. But you couldn't quite pinpoint, did it really come from that crazy source or not?

• 19:39Neil deGrasse Tyson?

  Your uncertainty circle was huge.

• 19:42Speaker 00

  Exactly.

• 19:42Neil deGrasse Tyson?

  Yeah, okay. So now you're doing a little better.

• 19:44Speaker 00

  Oh, a lot better. Yeah, yeah, yeah. Uh, to, you know, a fraction of a degree. It still sounds pretty sloppy.

• 19:50Neil deGrasse Tyson?

  So observer that you are.

• 19:51Speaker 00

  Hmm.

• 19:52Neil deGrasse Tyson?

  Space telescopes have high value to you, being above the atmosphere.

• 19:56Speaker 00

  Oh, yeah.

• 19:56Neil deGrasse Tyson?

  Detecting your one particle a year or whatever, your one photon.

• 20:00Speaker 00

  Luckily, it's more than that.

• 20:01Neil deGrasse Tyson?

  Okay, I'm happy to hear. How many total gamma ray photons have you touched in your life?

• 20:07Speaker 00

  Oh, that, that's been plenty.

• 20:09Neil deGrasse Tyson?

  Plenty, okay.

• 20:10Speaker 00

  Yeah. Uh, like I was saying before, any, anytime one of those cosmic ray protons hits an ambient proton and the galaxy is full of those gas clouds. Um, they light up.

• 20:21Neil deGrasse Tyson?

  Oh, God.

• 20:22Speaker 00

  Yeah, so it's a, actually, it's a strong background.

• 20:24Neil deGrasse Tyson?

  It's a strong background, okay. All right. So you use the, the Fermi telescope?

• 20:29Speaker 00

  Hmm.

• 20:29Neil deGrasse Tyson?

  In what way?

• 20:30Speaker 00

  I've lately been studying, well, things that you can't detect, oddly enough. Um, so there's, there's all these different gamma ray.

• 20:37Neil deGrasse Tyson?

  You're detecting it with gamma rays? You think you can't detect with a regular telescope?

• 20:40Speaker 00

  No, no, you can, there are, are bright sources of gamma rays like pulsars and star forming galaxies and things like that. But, you know, if you look at all the pulsars that are out there, there's about 5,000 or so that have been detected in the radio. And many of them are detected as, as gamma ray sources as well, but only a couple of hundred, about 300. So what are the other 4,000 or so doing? We suspected that they would also be good sources of gamma rays. And so we were looking at all the gamma rays.

• 21:09Neil deGrasse Tyson?

  Just a weaker source?

• 21:10Speaker 00

  Yeah, yeah. So we were looking at all the undetected pulsars and gamma rays and stacking that signal together to see if as a population, they actually are gamma ray sources. And trying to, trying to, you know, figure out what their properties as a population are.

• 21:23Neil deGrasse Tyson?

  So when you stack, you are improving the signal to noise of your data?

• 21:27Speaker 00

  Yeah, exactly. It's the signal compared to the noise. We're trying to reduce the background.

• 21:31Neil deGrasse Tyson?

  So every time you stack, the noise slowly cancels itself because it's not additive. Right? The ups and the downs cancel.

• 21:40Speaker 00

  Ideally.

• 21:40Neil deGrasse Tyson?

  You have a signal, however low, if it's really there, every next time, you're gonna boost it.

• 21:45Chuck Nice?

  It's amplified.

• 21:45Neil deGrasse Tyson?

  It's amplified. And every next time, you're gonna tamp down the noise.

• 21:48Chuck Nice?

  Right.

• 21:49Speaker 00

  In real practice, with a particle detector like this, the background just always adds up to?

• 21:54Neil deGrasse Tyson?

  It does. Oh, man.

• 21:55Speaker 00

  But you do get a persistent additional signal from your source population. So we stack them both.

• 22:02Neil deGrasse Tyson?

  You have to beat it.

• 22:02Speaker 00

  Yeah, we stack them both.

• 22:04Chuck Nice?

  Okay.

• 22:04Speaker 00

  Stack the background, compare it to our targets, and then we, we get a signal above the background.

• 22:10Neil deGrasse Tyson?

  Okay, and so in the inventory of objects or phenomena that are in these catalogs that emerge from the stacked data, is it something other than a pulsar or a supernova? Or are you discovering new kinds of objects?

• 22:28Speaker 00

  Maybe, because pulsars at very low gamma ray luminosities, some people say they shouldn't do that. And we're discovering that we're seeing them, that these low spin down, they're called low spin down pulsars, are actually potential sources of gamma ray emission. So there's just a lot that we don't know about the gamma ray production of pulsars. It comes out in a wacky area of their magnetosphere and...

• 22:52Chuck Nice?

  It does feel good when someone says... Can you just, just for the sake of the people who may not know, because I know.

• 22:59Neil deGrasse Tyson?

  For others.

• 23:00Chuck Nice?

  Yeah, for other people. Like, what is a pulsar and why is it so important when you talk about spin?

• 23:06Speaker 00

  Yeah, so a pulsar is the densest kind of object in the universe that we can measure. It's all the, it's all the superlatives like that, right? It is the densest. We're talking something a couple of times the mass of the sun, but the size of Queens.

• 23:22Chuck Nice?

  Okay.

• 23:22Speaker 00

  So, super-compact.

• 23:24Chuck Nice?

  That's wild.

• 23:24Speaker 00

  Can't go any more compact or you get a black hole.

• 23:26Neil deGrasse Tyson?

  Queens, a borough of New York City. For international.

• 23:29Chuck Nice?

  It's a black hole that you can actually observe. Or right before a black hole that you can actually observe.

• 23:34Speaker 00

  Exactly, yeah. So, super-dense, because of that, it has an incredibly high surface gravity. Right? So, like 100 trillion times the surface gravity that's keeping us in our seats right now.

• 23:47Chuck Nice?

  Oh.

• 23:48Speaker 00

  So, if you weighed a pound.

• 23:49Chuck Nice?

  Right.

• 23:50Speaker 00

  Right here, you'd weigh 100 trillion pounds on the surface of a neutron star.

• 23:55Neil deGrasse Tyson?

  You'd be flat as a flapjack.

• 23:57Chuck Nice?

  You'd be a grease spot.

• 23:58Neil deGrasse Tyson?

  A spot, that's all. Not even a flapjack.

• 24:00Chuck Nice?

  Just a spot.

• 24:01Neil deGrasse Tyson?

  Not even a tortilla.

• 24:04Chuck Nice?

  A little spot.

• 24:04Speaker 00

  But then they pulse, right? This pulsing is that they're spinning around really super-crazy fast. Also, some of the fastest spinning things. They spin faster than a blender.

• 24:14Chuck Nice?

  Okay.

• 24:16Speaker 00

  Double the mass of the sun, the size of Queens.

• 24:18Chuck Nice?

  Size of Queens.

• 24:19Speaker 00

  Spinning faster.

• 24:20Chuck Nice?

  Faster than a blender.

• 24:21Speaker 00

  Yeah.

• 24:21Chuck Nice?

  Wow.

• 24:22Speaker 00

  Yeah. It's pretty nuts.

• 24:23Chuck Nice?

  That's wild.

• 24:24Speaker 00

  Spinning so fast, they could almost fly to pieces. I mean, they're, it's that fast. Because of that fast spin and that high compression, they have these powerful, powerful magnetic fields, like trillion times higher than the magnet that's on your fridge. And that generates these intense electrical fields that'll accelerate particles. Just like the particles that the particle accelerator here on Earth.

• 24:45Neil deGrasse Tyson?

  That's your particle accelerator. The universe has a particle accelerator.

• 24:48Chuck Nice?

  Look at that.

• 24:48Speaker 00

  And even though the surface gravity's so high, any particles that are, that are near the surface, and these are just electrons and stuff like that, they will be, instead of falling to the surface, despite that high gravity, they get shot off at almost the speed of light because of the intense electromagnetic fields.

• 25:05Chuck Nice?

  Look at that.

• 25:06Neil deGrasse Tyson?

  So that means we understand gamma rebursts? Is that what you're saying?

• 25:09Speaker 00

  That's a stretch.

• 25:11Neil deGrasse Tyson?

  Okay, okay.

• 25:11Speaker 00

  Yeah.

• 25:12Neil deGrasse Tyson?

  All right.

• 25:13Speaker 00

  So a gamma ray burst is a different thing. So this is, this is during a stellar explosion like a supernova. Something happens as the core of that star collapses and then...

• 25:23Neil deGrasse Tyson?

  Anytime a scientist says something happens?

• 25:25Speaker 00

  Yeah.

• 25:26Neil deGrasse Tyson?

  We're gapping, gapping ignorance. There's a whole ignorant valley there.

• 25:30Chuck Nice?

  Right. There's a whole world inside of something happens.

• 25:33Neil deGrasse Tyson?

  A whole world, right.

• 25:34Speaker 00

  Well, people are modeling it and getting pretty good at it. There's a student in our group, a master's student, who's been doing these gamma ray burst explosions, but...

• 25:41Neil deGrasse Tyson?

  Master's degree.

• 25:42Speaker 00

  Yeah.

• 25:42Neil deGrasse Tyson?

  That's just a master.

• 25:44Speaker 00

  Of the universe.

• 25:45Neil deGrasse Tyson?

  Or master class.

• 25:46Speaker 00

  Which would be kind of cool, though, if you're an astrophysicist.

• 25:48Neil deGrasse Tyson?

  Master's degree student, yes.

• 25:49Chuck Nice?

  Yes. That'd be the degree they should give you as an astrophysicist. You are now a master of the universe.

• 25:54Speaker 00

  That, I'm in favor of.

• 25:55Neil deGrasse Tyson?

  Yeah, but you change that, for sure. Well, let's, let's look at our cosmic queries and see what came in. Chuck, you have them all?

• 26:02Chuck Nice?

  I have them right here.

• 26:03Neil deGrasse Tyson?

  You've got them all, bring it on.

• 26:04Chuck Nice?

  Yeah, well, let's start with Heywood from Atlanta, Georgia. This is...

• 26:09Neil deGrasse Tyson?

  Heywood's asked before, I think, Heywood.

• 26:11Chuck Nice?

  Yeah, he says, hello Neil, Tim, Chuck. Uh, just wondering, do gamma ray bursts start slowly and build over time? Or are they instantaneous? And by that, I think he means not the actual explosion, but the lead up to it. Cause there's no such thing as a slow-moving burst.

• 26:29Neil deGrasse Tyson?

  Right. You wouldn't call it a burst.

• 26:31Chuck Nice?

  You wouldn't call it a burst at that point. So, leading up to the actual, you know, expulsion of what we just talked about, what, what's that process? Do we have an idea of what that process is?

• 26:41Speaker 00

  Yeah, so it's the, the collapse of a massive star down to a black hole, presumably. Uh, but then, instead of just like this spherical explosion that you might picture, um, it's actually, uh, you get a jet, a couple of jets of explosive material, basically that, that blast out of the star. And they tend to be, those jets tend to be pointed right at us. And that gives you, um, a lot of that, that gamma, that high energy emission once it breaks out of the star.

• 27:08Chuck Nice?

  Right.

• 27:09Speaker 00

  But it's seconds. It's seconds. It's a pretty, really rapid rise, and then there's a slight fade. But it's still seconds, maybe tens of seconds. And those are so-called long gamma ray bursts. There are shorter ones that are much, much quicker.

• 27:21Chuck Nice?

  Tens of seconds, and that's the longest.

• 27:23Neil deGrasse Tyson?

  Wait, wait, so how do you know it's that short? Has anyone witnessed that? Yeah.

• 27:27Speaker 00

  Yeah, we see the light curves of their explosion and then the

• 27:31Neil deGrasse Tyson?

  So somebody's looking at it before it explodes.

• 27:34Speaker 00

  Yeah.

• 27:34Neil deGrasse Tyson?

  And then they see it while it's exploding in those tens of seconds. Even though the sky is vast and we don't not enough astronomers in the world to look at every star at all times.

• 27:42Speaker 00

  Yeah.

• 27:42Neil deGrasse Tyson?

  But you had people looking at the right star at the right time.

• 27:44Speaker 00

  Well, not just people, the Fermi Gamma Ray Space Telescope has an instrument that's looking at the whole sky all the time.

• 27:50Neil deGrasse Tyson?

  Oh, there you go. Okay, so it wasn't a pointed observations, it was a it was a broad.

• 27:55Speaker 00

  It's part of a survey.

• 27:56Neil deGrasse Tyson?

  Survey, okay.

• 27:57Speaker 00

  Exactly.

• 27:57Neil deGrasse Tyson?

  All right, give me more Chuck.

• 27:59Chuck Nice?

  Let's keep moving, let's go with Warma. Or Roam- Roama. Roama, who says, hello, Dr. Tyson, Professor Paglione and Lord Nice, Andrew here from Cork in Ireland. And then he says, I suppose it's in Gaelic, a thousand welcome, a hundred thousand welcomes. And I'm not going to try to pronounce that, sorry buddy. He goes, my question for you today is, can you explain how the properties of the largest molecular clouds in galaxies influence star formation rates and the overall dynamics of galaxies? Hmm, I love that. That's a great question.

• 28:39Speaker 00

  Yeah.

• 28:40Chuck Nice?

  That's a really great question.

• 28:41Speaker 00

  Yeah, this is where I I started before doing the gamma rays with studying these star formation and giant molecular clouds.

• 28:48Neil deGrasse Tyson?

  Was your PhD on that?

• 28:48Speaker 00

  Yeah.

• 28:49Neil deGrasse Tyson?

  Oh, cool.

• 28:50Speaker 00

  Yeah, in fact, there's not not a word of gamma rays went into my PhD thesis. But the one paper I did as a grad student on it was one of my most highly cited papers.

• 28:59Neil deGrasse Tyson?

  Nice.

• 28:59Speaker 00

  It's kind of funny, and now I all I do is gamma rays. I was waiting for Fermi to get launched. Yeah, the star formation happens in these giant molecular clouds. And so that's that's where all the action is. So, yeah, the properties of the molecular clouds definitely determines how it all plays out.

• 29:17Chuck Nice?

  Wow. And do the any of these other phenomena like, I don't know, the collision of black holes or these pulsar ejections and all of these particles that are excited and then jetted across the universe? Do they ever perturb these other, you know, like clouds and things to cause something that we can observe or?

• 29:40Speaker 00

  You know, it's interesting when you're talking about black holes and this and that, I was I'm I'm rolling in my head, I'm like, no, no, no, no. But the cosmic rays that we've been talking about, they can penetrate into the molecular clouds. Deeper than anything else.

• 29:55Chuck Nice?

  Okay.

• 29:55Speaker 00

  And provide a source of heat. And what we've noticed is that molecular clouds are a little hotter than one might predict. They should be really cool.

• 30:04Neil deGrasse Tyson?

  They're absorbing their...

• 30:05Speaker 00

  And so there seems to have always been an additional source of ionization, source of heating. And cosmic rays are that source.

• 30:13Chuck Nice?

  Okay.

• 30:14Speaker 00

  And this is one of the things that keeps me going in cosmic ray astrophysics is is seeing what the contribution of cosmic rays are to galaxy evolution and molecular cloud evolution, star formation.

• 30:26Neil deGrasse Tyson?

  So molecular clouds can be huge. That means they have a lot of gravity.

• 30:30Speaker 00

  Hmm.

• 30:31Neil deGrasse Tyson?

  Does that enough gravity influence other clouds? Or they're just into its own thing?

• 30:35Chuck Nice?

  Interesting.

• 30:36Speaker 00

  Uh, I mean, they can merge and do other stuff. But they, they tend to be really, you know, subject to the overall dynamics of, of the galaxy. So they'll follow the, the gravitational potential of, of the galaxy.

• 30:51Chuck Nice?

  All right, this is Ilya. Ilya says, hello, Dr. Tyson, Professor Paglione, and anyone else who might be there. Thanks.

• 31:00Speaker 00

  Your title is Lord.

• 31:01Chuck Nice?

  This is true, yes.

• 31:04Chuck Nice?

  Uh, here's a question from beautiful Portland, Oregon. From the limited knowledge, uh, gamma is the highest photon energy we have encountered in the universe. But we have also produced photons with much higher levels and particle accelerators here on Earth. Does the equipment you use in your studies have the capacity to detect and differentiate such particles? But the truth is, have we really?

• 31:29Speaker 00

  Nah, you can't compete with the cosmos, man. No, they totally have us beat.

• 31:34Neil deGrasse Tyson?

  So the cosmos is a they in that sense? I'm just doing...

• 31:37Speaker 00

  Sure.

• 31:38Neil deGrasse Tyson?

  How you're personifying the universe.

• 31:40Speaker 00

  The LHC is able to bang together protons at, I think it's like 14, uh, tera electron volts, which is just a whole crap load of electron volts. It's very high energy.

• 31:50Chuck Nice?

  Hmm.

• 31:50Speaker 00

  But we've got, there are sources out there that work a thousand times higher.

• 31:55Chuck Nice?

  Thousand times.

• 31:55Speaker 00

  Yeah, we're getting cosmic rays and, and, uh, there, there are gamma rays that we're seeing from, from sources that we truly don't understand how they can be that energetic.

• 32:05Neil deGrasse Tyson?

  Isn't that our best evidence that the Large Hadron Collider would not create many black holes that would eat Earth when they turned on the switch?

• 32:12Speaker 00

  Oh, that's an interesting question.

• 32:13Neil deGrasse Tyson?

  Yeah, because... The energetics of the collider, though high, pale compared to the actual collisions happening in our actual atmosphere.

• 32:22Speaker 00

  Yeah.

• 32:23Neil deGrasse Tyson?

  And so you can't worry that that's going to turn us into a black hole when

• 32:28Speaker 00

  When you have higher energy reactions that are happening right above us all the time.

• 32:32Neil deGrasse Tyson?

  All the time.

• 32:33Speaker 00

  Yeah.

• 32:33Chuck Nice?

  That makes sense.

• 32:34Speaker 00

  I think the record is 20 TEV for the highest energy photon detected on the earth. It might be higher now, but that requires a process or a particle that's even more energetic. And so they're out there. They're out there and we can't touch that.

• 32:48Chuck Nice?

  Can't touch it.

• 32:48Neil deGrasse Tyson?

  Can't touch this.

• 33:10Chuck Nice?

  So this is Kayla Borden-Badur. She says, "Salutations from Lafayette, Louisiana. Kayla here, curious about gamma ray telescopes. How exactly do they work? Are they used to investigate and why do we never hear about them?"

• 33:27Neil deGrasse Tyson?

  I know. How come? Because you don't make pretty pictures.

• 33:29Speaker 00

  I don't know.

• 33:29Neil deGrasse Tyson?

  It's gotta be it. People like pictures.

• 33:31Speaker 00

  Yeah, that's true.

• 33:32Neil deGrasse Tyson?

  You say, "I had three photons today." That does not make a headline.

• 33:36Chuck Nice?

  Oh.

• 33:37Speaker 00

  Yeah, the pictures are kinda grainy. I'll admit that, but you know, we usually

• 33:42Chuck Nice?

  Tim, that's why there's Photoshop.

• 33:44Speaker 00

  Yeah.

• 33:47Speaker 00

  Or artist's impressions. You know, it's a particle detector.

• 33:51Chuck Nice?

  Right.

• 33:51Speaker 00

  So the particle comes in, it goes through these layers of tungsten, basically, and it'll create a particle antiparticle pair, and that pair travels through the tracker, the so-called tracker, and that lets us know where it came from.

• 34:07Chuck Nice?

  Oh.

• 34:08Speaker 00

  And then it lands in this silicon calorimeter, which is just an energy measure. And that's the way it works.

• 34:16Chuck Nice?

  All right, so that's super cool, man.

• 34:18Neil deGrasse Tyson?

  So what, tell us about a calorimeter?

• 34:19Speaker 00

  So the, the particle eventually ends up in this, this calorimeter and that's, that's just overall measuring the total energy.

• 34:27Neil deGrasse Tyson?

  Okay.

• 34:27Chuck Nice?

  Got you. Like a collection plate?

• 34:30Speaker 00

  So, you know, we, like I said, we get three things.

• 34:33Neil deGrasse Tyson?

  Its root is calorie.

• 34:34Speaker 00

  Yeah.

• 34:35Neil deGrasse Tyson?

  Yeah, calorie, energy.

• 34:36Chuck Nice?

  Oh, cool. Yeah. So it's heat?

• 34:38Neil deGrasse Tyson?

  Yeah, or energy.

• 34:40Chuck Nice?

  Energy, right, yeah, exactly.

• 34:41Neil deGrasse Tyson?

  Which can manifest as heat.

• 34:43Chuck Nice?

  But it's energy. Excellent.

• 34:45Speaker 00

  Technically, heat is exchanged energy.

• 34:48Chuck Nice?

  Got you.

• 34:49Speaker 00

  Yeah.

• 34:49Chuck Nice?

  Cool. All right, you see how specific these scientists are, people? You see what a pain in the ass this is?

• 34:57Neil deGrasse Tyson?

  But it facilitates efficient communication.

• 35:00Chuck Nice?

  That I cannot disagree with, okay?

• 35:03Neil deGrasse Tyson?

  Excellent thing.

• 35:03Chuck Nice?

  Right. All right, here we go. This is Christopher Stowe, who says, "Hi, Chris in Pennsylvania here. My question is about the chemistry that occurs in these huge clouds. Is there complex chemistry occurring in the nebula, or is the material too diffuse for this to happen?"

• 35:19Neil deGrasse Tyson?

  Good question.

• 35:21Speaker 00

  Yeah, that's really insightful, because it-

• 35:23Chuck Nice?

  This dude knows what he's talking about here.

• 35:24Speaker 00

  It is diffuse, extremely diffuse. You might, in a dense molecular cloud, you might have a thousand particles in a cubic centimeter, so the size of a die, you know? So that's not much, so they don't interact a lot.

• 35:35Neil deGrasse Tyson?

  A die, you mean a dice, dice?

• 35:36Speaker 00

  One, one die.

• 35:37Chuck Nice?

  One dice, right.

• 35:39Speaker 00

  So, yeah, the, the chemistry's there, but it's slow. Gas phase chemistry is just really slow.

• 35:44Neil deGrasse Tyson?

  Slow because of the separation among the, the frequency of interaction is so low.

• 35:49Speaker 00

  Yeah.

• 35:50Neil deGrasse Tyson?

  It's, the experimenting is not sensibly, happening on a sensible time scale.

• 35:55Speaker 00

  Yeah, you can't make a compound out of two atoms if they don't meet up, you know, so it's just, yeah, it's just slow. It happens, and you can get complex molecules, but it's, it's slow. And molecular clouds don't live that long.

• 36:08Chuck Nice?

  Oh.

• 36:08Speaker 00

  Yeah, millions of years, they're a little transient, so.

• 36:11Chuck Nice?

  Got you.

• 36:12Speaker 00

  No, I'm sorry, that was an astronomical time scale there. That's, that's fast.

• 36:15Chuck Nice?

  Right, okay, there you go.

• 36:18Neil deGrasse Tyson?

  Well, they don't live, so what happens to them?

• 36:20Speaker 00

  Well, they could collapse to form stars, or they could dissipate or be disrupted. They're all very turbulent, so they could just fly to pieces.

• 36:27Neil deGrasse Tyson?

  Okay.

• 36:27Speaker 00

  Yeah.

• 36:28Chuck Nice?

  Okay, alright, this is, uh, Sajaminkinen. Sajaminkinen, who says, "Hello." I'm guessing it's not that. I mean, how about this? I'm just guessing. Saya Minkinen, okay, how about that? Uh, "Hello from the distant snowy lands of Finland. My name is Saya Minkinen, pronounced Saya." Oh, guess who got it right! Oh, for once, I had it wrong the first time, until you said, "Maybe not." Uh, "The last name, sorry, I can't help you there, Chuck."

• 37:04Chuck Nice?

  You jackass. Alright, here you go, Saya. Here's my question. "If there are regions in the galaxy where stars are born and die very quickly, could these starbursts in some way be considered the vital functions of galaxies themselves? In other words, do they act as the breathing or the pulse of galaxies, shaping their life cycle and their evolution?"

• 37:29Speaker 00

  Boy, you sound like you've been working with Neil for a while.

• 37:34Speaker 00

  Yeah, that's a great question, and, and it's, it's kind of the thing that, that got me into the galaxy cluster project.

• 37:41Chuck Nice?

  The pulse of the galaxy.

• 37:42Speaker 00

  Yeah, because galaxies form, uh, from infalling gas and things like that, but then there's also this process of feedback, because you get supernova explosions and things like that, or stellar winds, and when it's all happening in one burst like that, you can get these giant super bubbles or galactic-scale winds that are coming out of galaxies, and then, um, reseeding their, their neighborhood, and even turning off the star formation. So it's all regulated by these feedback mechanisms.

• 38:13Chuck Nice?

  That's wild.

• 38:14Speaker 00

  They also generate cosmic rays, which can carry away a bunch of the energy as well. It's another thing I've been looking at.

• 38:21Chuck Nice?

  Very, very cool. Great question, Saya. Way to go.

• 38:25Speaker 00

  Mm-hmm.

• 38:25Chuck Nice?

  I'll forgive you for making fun of me. All right. This is Michael Kemp, who says, "Greeting Dr. Tyson, Lord Nice, Dr. Paglione, Paglione, Paglione, sorry."

• 38:35Speaker 00

  Rhymes with telephone, I tell my students.

• 38:38Chuck Nice?

  Uh, Michael Kemp here, from soggy Oregon coast range in the southwest of Eugene. James Webb Space Telescope has imaged tons of supernova from the early universe. Are these early supernovae different from the ones occurring in our universe today? It thanks a lot. What would make them change?

• 39:00Speaker 00

  Well, that's a great question. Uh, it's actually a big problem. Uh, what we assume is that they're the same as supernova that we know and love, the ones that we're really familiar with that are nearby. And we're kinda hoping that they probably are the same, so that we understand what they're like.

• 39:17Chuck Nice?

  Right.

• 39:17Speaker 00

  Now, what he's referring to, though, there's been dozens of new transients discovered by the James Webb Space Telescope.

• 39:25Chuck Nice?

  Please explain transients.

• 39:27Speaker 00

  Yeah, things that just blinked on and then went away.

• 39:29Chuck Nice?

  Oh, get out!

• 39:31Speaker 00

  Yeah.

• 39:32Chuck Nice?

  But don't repeat.

• 39:32Speaker 00

  Transient, like an explosion.

• 39:34Chuck Nice?

  That's wild.

• 39:35Speaker 00

  Mm-hmm.

• 39:37Chuck Nice?

  Okay. That's, but that's crazy, though.

• 39:40Speaker 00

  So, we presumed they're supernova, but we're actually still, I think they're still studying what the heck they are. This is really new stuff. I mean, this guy's up on...

• 39:47Chuck Nice?

  Yeah, he's up on this stuff. Way to go, Michael Kemp. Look at that. You impressed the doctor here, okay? All right, this is Gavin Bamber, who says, "Hello from North Vancouver. Please visit us." Okay, thanks for the invitation.

• 39:58Speaker 00

  Absolutely.

• 39:59Chuck Nice?

  I'll be expecting my plane ticket.

• 40:02Chuck Nice?

  Uh, "Was our sun a star that was formed from the debris of a massive star? If so, or not, how many dying stars does it take to form a new star?"

• 40:17Speaker 00

  Mmm.

• 40:17Chuck Nice?

  Interesting.

• 40:19Speaker 00

  So yeah, we're definitely a second generation week. The Sun is definitely a second generation star, what we call a Population One star. Even though it's second generation, Pop Two came first, I don't know, astronomers.

• 40:30Chuck Nice?

  But Pop Two came first, Pop One came second.

• 40:32Speaker 00

  Yeah.

• 40:33Chuck Nice?

  Okay. Deal with it. That's weird.

• 40:34Speaker 00

  There's Pop Three now also, which were the first stars.

• 40:37Chuck Nice?

  Which was before everything.

• 40:38Speaker 00

  Yeah.

• 40:39Chuck Nice?

  That's ridiculous.

• 40:40Speaker 00

  Anyway, well, the Sun is definitely a Pop One star, so it has heavier elements in it, like magnesium and whatnot, you know. And these things come from exploding stars and other, you know, evolved stellar things. So yeah, for sure, we're from the debris of a lot of different stars then. So all that, you know, when a star explodes or throws off its outer layers, when it's a giant or things like that, you know, that all goes back in the interstellar medium, eventually forms another giant molecular cloud.

• 41:10Chuck Nice?

  Right.

• 41:10Speaker 00

  And then forms the next generation of stars.

• 41:12Chuck Nice?

  Falls in and forms a star. That's pretty wild. Next gen. Next gen. Gen X.

• 41:20Chuck Nice?

  I love it. Let's start naming them. We're a Gen X star. Population One Two, that's not catchy. Yeah, it really isn't. Just start. All right, this is Alyssa Feldhaus. Alyssa Feldhaus, who says, Alyssa from Rocket City, Huntsville here. Dr. Pavillon, can we trace the features in younger galaxies directly to these early starburst galaxies? And might they be considered progenitors of the galaxies we observe today? And why pray tell is my favorite candy named after them? Thanks for keeping me up. Starburst. Yeah. Starburst. Right there, you have some on your desk over there.

• 42:00Speaker 00

  Oh, very nice.

• 42:00Chuck Nice?

  Look at that.

• 42:01Speaker 00

  I mean, the answer to her question in short is yeah.

• 42:04Chuck Nice?

  This is when you know you're in a real astrophysicist's office. When you see some starbursts sitting around. Anyway, yeah, you want one? There you go.

• 42:13Speaker 00

  I think that's just a cool name. I'm not in the marketing, uh, marketing firm for these guys, but yeah.

• 42:18Chuck Nice?

  Yeah, just went for it, yeah.

• 42:20Speaker 00

  In astronomy, Neil wrote about this a long time ago. You know, we, we use simplistic naming.

• 42:25Chuck Nice?

  Love it.

• 42:25Speaker 00

  We're not, we're not super fancy with the names. If there's a burst of star formation in a galaxy, we call it a star burst galaxy, you know?

• 42:31Chuck Nice?

  That's it.

• 42:32Speaker 00

  Get right to the point. But yeah, I mean, the earliest galaxies were forming a lot of stars. They were smaller, obviously, and really messed up. And, uh, and yeah, we, we try to make those connections. But the star formation rate in, earlier in the universe was a lot higher than it is today. So, you know, things were, were, we're definitely interested in trying to tie all those together.

• 42:54Chuck Nice?

  Cool. Time for one more question, Chuck. All right, let's go to our buddy Alejandro Reynoso.

• 43:02Chuck Nice?

  He's from Hackensack, New Jersey.

• 43:03Speaker 00

  Oh, okay. He's not the big king.

• 43:05Chuck Nice?

  Alejandro Reynoso from Monterrey, Mexico. Hello, or should I say hola? There's that on there.

• 43:19Chuck Nice?

  Oh, he says this. My question is, how massive stars? How do they behave different from our sun? Is the only difference in how they die?

• 43:30Speaker 00

  No, it's also in how they're born and how they live. So it's everything.

• 43:35Chuck Nice?

  Oh my God.

• 43:35Speaker 00

  Yeah, massive stars do everything just fast.

• 43:38Chuck Nice?

  So let's talk about how they're born, because that's pretty doggone interesting.

• 43:42Speaker 00

  Well, it's the same way the sun or, or a low mass star is born. It's a collapse of a molecular cloud.

• 43:46Chuck Nice?

  Right.

• 43:47Speaker 00

  The, but the massive star just does it faster.

• 43:49Chuck Nice?

  Okay, because of all the mass.

• 43:51Speaker 00

  Yeah, and gravity. So it's just all happens faster.

• 43:54Chuck Nice?

  All right. So now, I'm this big, giant, fat superstar. And I'm just burning away, baby. What am I doing differently than?

• 44:06Chuck Nice?

  The kind of star that we have. And then what am I doing differently than like a brown dwarf? Like a little boring ass brown dwarf star.

• 44:16Speaker 00

  It's the burning away baby that you were talking about. It's the burning. Yeah, it's all in the burning. So the sun at the core.

• 44:23Neil deGrasse Tyson?

  But just to be clear, we don't use the word burn the same way the chemist does.

• 44:27Chuck Nice?

  Yeah, of course. Of course you wouldn't.

• 44:29Neil deGrasse Tyson?

  The chemist's burn is a chemical reaction.

• 44:32Chuck Nice?

  Right.

• 44:33Neil deGrasse Tyson?

  Usually involving oxygen.

• 44:34Chuck Nice?

  Right.

• 44:35Neil deGrasse Tyson?

  Where it's exothermic and releases. We say burn.

• 44:38Chuck Nice?

  Right.

• 44:39Neil deGrasse Tyson?

  But we don't mean burn.

• 44:40Chuck Nice?

  What you really mean is what? Well, we're reacting.

• 44:44Neil deGrasse Tyson?

  So we mean thermonuclear fusion.

• 44:46Chuck Nice?

  Oh, of course. Yes.

• 44:47Neil deGrasse Tyson?

  So it's a loose tongue. It's just a loose tongue. We're all guilty of that. That's why I slipped that in there. Okay.

• 44:54Chuck Nice?

  So here you are, you're doing your thermonuclear fusion.

• 44:56Speaker 00

  Yes.

• 44:57Neil deGrasse Tyson?

  And we're talking about hydrogen burning.

• 44:58Chuck Nice?

  Right, that's hydrogen burning.

• 45:00Speaker 00

  So that's what the sun is doing.

• 45:01Chuck Nice?

  That's the sun.

• 45:01Speaker 00

  Yeah, burning hydrogen and creating helium.

• 45:04Chuck Nice?

  Right. So it's helium, helium. So what's the big fat guy doing?

• 45:08Speaker 00

  So they have enough mass to compress the core to higher temperatures so that they can burn helium into carbon.

• 45:15Chuck Nice?

  Oh.

• 45:16Speaker 00

  Or even better, burn carbon into oxygen.

• 45:20Chuck Nice?

  Oh.

• 45:20Speaker 00

  Or even better, the next one and the next one and the next one until you get up to iron.

• 45:27Chuck Nice?

  So they're just making all these elements.

• 45:29Speaker 00

  Yeah.

• 45:29Chuck Nice?

  As they burn?

• 45:30Speaker 00

  Yep.

• 45:31Chuck Nice?

  Whoa.

• 45:32Speaker 00

  Nucleosynthesis.

• 45:33Chuck Nice?

  Nucleosynthesis. So that is not just a part of the dying process before they become explode?

• 45:40Speaker 00

  That's the living process.

• 45:41Chuck Nice?

  That's just the living process?

• 45:42Speaker 00

  Yeah.

• 45:42Chuck Nice?

  Interesting.

• 45:43Speaker 00

  And that, each one of those is a very energetic process, so they burn fast. And so even though, you know, they have more mass and so you would think, oh, with more fuel in the tank, you'd last longer. Now, they burn it up really, really fast.

• 45:56Neil deGrasse Tyson?

  Way faster.

• 45:57Speaker 00

  Yeah. They're super luminous. I mean, they could be thousands of times more luminous than the sun. And so they're shining, they're giving off energy that much faster.

• 46:07Chuck Nice?

  Now, does the size compensate for the longevity or do they just burn out quicker?

• 46:11Speaker 00

  They burn out quicker.

• 46:12Chuck Nice?

  Oh.

• 46:12Speaker 00

  They might only last 10 million years.

• 46:14Chuck Nice?

  Oh.

• 46:15Speaker 00

  Yeah.

• 46:15Neil deGrasse Tyson?

  Instead of a trillion.

• 46:16Chuck Nice?

  Ah, right?

• 46:17Neil deGrasse Tyson?

  Yes.

• 46:17Speaker 00

  Yeah. So this is why when star formation's happening, massive star formation?

• 46:21Chuck Nice?

  Yeah.

• 46:21Speaker 00

  It's instantaneous. If you see a massive, there are no old massive stars.

• 46:26Chuck Nice?

  Look at that.

• 46:26Speaker 00

  There just aren't.

• 46:27Chuck Nice?

  It's better to burn out than it is to fade away.

• 46:32Neil deGrasse Tyson?

  What's that from? That's.

• 46:33Chuck Nice?

  That's Highlander.

• 46:35Neil deGrasse Tyson?

  No.

• 46:35Chuck Nice?

  Yes.

• 46:36Neil deGrasse Tyson?

  There's another one.

• 46:36Speaker 00

  Really?

• 46:36Chuck Nice?

  That's Highlander.

• 46:37Speaker 00

  That has two catchphrases? It's not there can be only one?

• 46:40Chuck Nice?

  That that is the number one catchphrase.

• 46:42Speaker 00

  Yeah.

• 46:42Chuck Nice?

  But the anti-hero in the movie, that's his line. It's better to burn out than it is to fade away.

• 46:49Neil deGrasse Tyson?

  There's a rock song that has that. It's better to burn out than to fade away. It's Neil Young.

• 46:53Chuck Nice?

  Oh, Neil Young.

• 46:54Neil deGrasse Tyson?

  Hey, hey.

• 46:55Speaker 00

  My favorite Highlander line is actually, it hurts, doesn't it? He stabs him in the neck.

• 47:03Neil deGrasse Tyson?

  That's your favorite?

• 47:04Speaker 00

  Yeah. This is kind of cruel because he knows he won't die. Just stabbed him in the neck.

• 47:08Neil deGrasse Tyson?

  Oh, okay.

• 47:08Speaker 00

  Hurts, doesn't it?

• 47:09Chuck Nice?

  Wow, so big giant stars, they live fast and die young.

• 47:13Speaker 00

  Absolutely.

• 47:14Chuck Nice?

  Awesome.

• 47:15Speaker 00

  Yeah.

• 47:15Neil deGrasse Tyson?

  Even though they had more fuel.

• 47:17Chuck Nice?

  Even though they have more fuel.

• 47:18Neil deGrasse Tyson?

  They're like gas guzzling land yachts of the 1960s and 70s.

• 47:23Chuck Nice?

  I like to think of more.

• 47:24Neil deGrasse Tyson?

  They had bigger gas tanks, but they would not go as far.

• 47:26Chuck Nice?

  Right.

• 47:26Neil deGrasse Tyson?

  As the smaller gas tank, they got better gas mileage.

• 47:28Chuck Nice?

  That's right.

• 47:29Neil deGrasse Tyson?

  Same analysis.

• 47:31Chuck Nice?

  Very cool.

• 47:32Neil deGrasse Tyson?

  Uh, let me see if I can reflect on our conversation.

• 47:34Chuck Nice?

  Yeah.

• 47:35Neil deGrasse Tyson?

  With a cosmic perspective.

• 47:36Chuck Nice?

  Okay.

• 47:38Neil deGrasse Tyson?

  What has always fascinated me with science in general, but astrophysics in particular, is that there are things you know and love and see that you have telescopes and detectors. You hypothesize what's there and you get more better data and you figure it out. Then you realize you're still only limited by the power of your tools. And you wait, we actually wait until a bigger telescope comes along, a better telescope comes along, a more powerful particle accelerator comes along that could reach into.

• 48:23Neil deGrasse Tyson?

  Zones of the universe that were previously unknown. And so, for me, it's not just about how clever are you with what we already know. It's you gotta bring in the engineers at some point to build the thing to be able to even see where you had never imagined was even possible. And that's where the significant growth in a field comes from. Not only from brilliant people thinking about stuff we already know about. It comes from brilliant technologies that could take us not only where we've never been, on occasion, where we've never even dreamt of. And that's a cosmic perspective.

• 49:08Neil deGrasse Tyson?

  Tim, thanks for coming. Hey, thank you. Thanks for making the trip from upstairs. Here at the Rose Center for Earth and Space, Hayden Planetarium, American Museum of Natural History. That's your visitors' office, right? Because you're based at York College. That's right. Yeah, so thanks for coming. Absolutely. Glad to be here. Chuck, always good to see you, man. Always a pleasure. All right, this has been StarTalk Cosmic Queries, the Extreme Energy Edition. Until next time, keep working up.