Low-Mass Mania with Emily Rice

Could we find life around low-mass stars? Neil deGrasse Tyson and comedian Chuck Nice find out why life might be more likely around low-mass stars, what makes brown dwarfs, galactic archeology, and more with astronomer Emily Rice.

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

• 0:00Neil deGrasse Tyson?

  Coming up on StarTalk Cosmic Queries, my friend and colleague Emily Rice is going to tell us all about the latest in brown dwarfs and exoplanets. Oh, yeah. That all comes to you from right here in my office at the Hayden Planetarium of the American Museum of Natural History.

• 0:20Neil deGrasse Tyson?

  Welcome to StarTalk, your place in the universe where science and pop culture collide. StarTalk begins right now.

• 0:33Neil deGrasse Tyson?

  This is StarTalk Cosmic Queries Edition. Got Chuck Nice with me. Chuck, how you doing, man? Hey, what's happening, Neil? All right. You know, there's a part of the universe that is a little foreign to me because most of my research back when I was like active with it was galaxies, large-scale structure, Big Bang. And you come down, you get closer and closer and closer. There's a whole world there. Right. Literal and figurative world. Okay. People think about planets and stars being born around which you would find planets. Right. And we got one of the world's experts right here in the house. Oh. And here she goes.

• 1:10Speaker 01

  Yes.

• 1:11Neil deGrasse Tyson?

  Emily Rice, Emily, friend and colleague. How you doing?

• 1:14Speaker 01

  I'm very excited to be here again.

• 1:15Neil deGrasse Tyson?

  Welcome back.

• 1:16Speaker 01

  Thank you, yeah.

• 1:18Neil deGrasse Tyson?

  To StarTalk. And just let the record show that whatever I'm wearing that's cosmic, and people say, oh, that's cool, that's cosmic. Right. I just want you to know that when I'm- Emily will come in with something cooler. When I'm with my people, it's just camouflage. Because everybody else has got something.

• 1:35Speaker 01

  Now it is, yeah.

• 1:36Neil deGrasse Tyson?

  And you were like leader of the pack there. Aren't you involved in some haberdashery or something? Yeah, haberdashery. What, clothing?

• 1:45Speaker 01

  A little bit of this, a little bit of that.

• 1:46Neil deGrasse Tyson?

  Don't you have a jewelry line?

• 1:47Speaker 01

  Yeah.

• 1:48Neil deGrasse Tyson?

  Or do you still have a jewelry line?

• 1:49Speaker 01

  It's a super long story, but yeah, we, so, it started as a phenomenological, like, we noticed people. You know, you were one of the originals, but other people were doing it too.

• 1:58Neil deGrasse Tyson?

  You're an OG? Ooh, look at that.

• 2:00Speaker 01

  I think you might be one of the first, yeah.

• 2:02Neil deGrasse Tyson?

  To be loud in my attire.

• 2:04Speaker 01

  Yeah.

• 2:04Neil deGrasse Tyson?

  Yes, okay.

• 2:04Speaker 01

  But a bunch of people were doing it. And so we started a blog originally, Summer Ash and I. Summer was at, um- Columbia at the time and we were doing our outreach stuff and wearing our stuff like our galaxy leggings and our NASA swag and stuff like that. We were like, we should, this is so cool because some of the stuff we noticed was real, you know, real Hubble images and stuff like that. And so we started a blog that was, we meant to like share it with the public, like, oh, you bought this thing, what is it, where did it come from, you know, astronomically, how it was obtained and stuff like that. Add some science. Yeah, add the science to it. What I didn't expect is for the rest of the astronomers to be so into it that like, we presented it at a research conference, but there's always room at the research conferences for outreach and education and things like that.

• 2:47Speaker 01

  And the number one question we got at our poster at the research conference was, where do I buy this stuff? Mmm. Like from the other astronomers. The birth. Yeah. The genesis. Can make stuff with my science. And at the time, we were just finding things that were out there, you know, people's Etsy shops and small designers, like it was kind of everywhere. You were an aggregator at the time. Yeah, curator, you know.

• 3:05Chuck Nice?

  Cosmological Joan Rivers. Oh, who are you wearing? What galaxy is that?

• 3:12Speaker 01

  Totally. But it's, and it's now become a shop. So, long story short, like we became an online shop, so we create our own stuff as well. And it's called? It's called Star Tori List. Star Tori List.

• 3:26Chuck Nice?

  Instead of Star Tori.

• 3:27Speaker 01

  You see what she did there? Exactly, yeah. Okay, well, cool. So it's online, we can find it online. Yeah, Star Tori List. So, we, I really thought it would be a fad that would just kind of happen and, you know, fade away, like not be popular anymore, which, you know, is kind of fine. But it hasn't. It's continued to grow. We've added our own stuff, so I say that we're the dark energy of the, of the fashion universe.

• 3:49Chuck Nice?

  Look at that.

• 3:50Speaker 01

  For astronomy. All right. Dark energy is a, is a power of expansion.

• 3:54Chuck Nice?

  Exactly.

• 3:55Speaker 01

  It accelerates the expansion of the universe.

• 3:57Chuck Nice?

  In other words, you're, you're unaware of why you are successful.

• 4:03Speaker 01

  Absolutely. Fully, it's not fully understood. It will be, we just need a little more.

• 4:09Neil deGrasse Tyson?

  Maybe, we don't know, we don't know. So, your expertise is newborn stars, exoplanets, brown dwarfs.

• 4:16Speaker 01

  Yeah.

• 4:18Neil deGrasse Tyson?

  And, I have an issue, first of all.

• 4:21Chuck Nice?

  Uh oh.

• 4:22Neil deGrasse Tyson?

  So, so when I think of a star, it's self luminous and it's

• 4:27Speaker 01

  Yes.

• 4:27Neil deGrasse Tyson?

  It's burning bright, even though burning to us is mean something different than to a chemist.

• 4:33Chuck Nice?

  Fusing bright.

• 4:34Neil deGrasse Tyson?

  Yeah, fusing bright, but that doesn't have the alliteration and it's not as cool.

• 4:38Chuck Nice?

  Right.

• 4:39Neil deGrasse Tyson?

  So, stars will burn bright, even if they're burning dimly, they still sort of luminous in the infrared or somewhere, okay. At no time am I thinking, I'm looking at a brown object. So, why did these

• 4:52Speaker 01

  Oh, yeah.

• 4:52Neil deGrasse Tyson?

  Why did these objects, which in the netherland between planets and stars?

• 4:58Speaker 01

  Yes.

• 4:59Neil deGrasse Tyson?

  Because I don't call planets brown, all right, because they're going to reflect light and they're going to have whatever colors they have. I don't call stars, where do you get the color brown from?

• 5:07Speaker 01

  The color brown apparently came from Jill Tarter, who you've had on your show before.

• 5:13Neil deGrasse Tyson?

  Yes, Jill's a friend of StarTalk.

• 5:14Speaker 01

  Yeah.

• 5:15Neil deGrasse Tyson?

  Active with SETI, Jill Tarter.

• 5:17Speaker 01

  Yeah, I love, I watched her interview on StarTalk once and she told the story of her early career, it was actually in her PhD thesis where she did some research on these objects that were previously called black dwarfs. And so it started in the 60s.

• 5:32Chuck Nice?

  Oh, so we had to take it away from the black.

• 5:36Chuck Nice?

  Well, that makes perfect sense. Couldn't just let it be a black dwarf, nope. Mm mm, no, we can't have that. Sure, a hole can be black, no problem. Yes, exactly, you know?

• 5:47Speaker 01

  We have white holes too, apparently, that's my expertise.

• 5:51Neil deGrasse Tyson?

  On paper, but not in a real thing.

• 5:53Chuck Nice?

  But anyway, sorry.

• 5:54Speaker 01

  So, the black dwarfs, yeah, they were black dwarfs originally because the idea was purely theoretical, was what happens when the stars don't have enough mass pushing down from the outside to get a high enough temperature at the inside to fuse hydrogen and helium as a steady source of power. And so they were called

• 6:10Neil deGrasse Tyson?

  Which is what the sun does every day of its life.

• 6:12Speaker 01

  Yeah, so this is why the sun creates energy, it's a stable source of energy, of pressure pushing outwards against gravity. And the idea is that these things that, these things that started to form like stars but wouldn't have enough mass would kind of Still continue to exist, but what would they look like? What would their structure be? How would they radiate? Things like that. That was first kind of described by a theoretical physicist in the 1960s. S.S. Kumar was his name. And then Jill Tarter, I think it was in 1975, in her thesis, kind of proposed the term brown dwarfs. And that kind of stuck. So she originally studied these objects. It's still at that point theoretical.

• 6:50Neil deGrasse Tyson?

  And of course, to Chuck's point, black holes were gaining very serious attention around that time.

• 6:56Speaker 01

  Yeah. And so I think that's what's like, like the way that we call stuff dark now.

• 7:00Neil deGrasse Tyson?

  It was a cover story of the New York Times Magazine. Black holes, what new research? So, so it took the word. I think you're right.

• 7:07Chuck Nice?

  Hmm.

• 7:08Speaker 01

  Yeah. But then they realized like, okay, they're not fully, you know, they're not fully unexplained. Like they are reasonably well explained by like kind of normal physics. And so they moved away from black and just called them brown. Jill Tarter on your show said, oh, you know, so I started out doing this and then I wanted to do research that mattered.

• 7:27Chuck Nice?

  Wow.

• 7:28Speaker 01

  Talking about her shift into study, which I'm like, I can't argue with that too much, but it's

• 7:33Neil deGrasse Tyson?

  But it is a little bit of a diss. It is a little bit of a diss.

• 7:36Chuck Nice?

  A little, yeah.

• 7:37Speaker 01

  Um, but it's an amazing, so, so she coined the phrase in, in 1975. And they still weren't known to exist. Like they weren't actually discovered until the 1990s. Even then it kind of took a while.

• 7:49Neil deGrasse Tyson?

  For context here, right? And I hate thinking this way, but it just jumps into my head. You realize, you just described something that happened 50 years ago.

• 7:57Speaker 01

  Yeah, more than, we had a conference, actually, 50 years after to celebrate the original papers, 1963, 64, so that's already 10 years ago.

• 8:05Neil deGrasse Tyson?

  Had it been 1975 and we had this conversation, you'd be talking about 1925 as 50 years earlier.

• 8:10Chuck Nice?

  Wow.

• 8:11Neil deGrasse Tyson?

  That's what I'm saying. This, this, this.

• 8:12Speaker 01

  Oh, God.

• 8:13Neil deGrasse Tyson?

  This, just to put that where.

• 8:16Chuck Nice?

  Yes, and, and, and in the proper context.

• 8:18Neil deGrasse Tyson?

  In the proper context.

• 8:19Chuck Nice?

  You know, you guys old.

• 8:21Neil deGrasse Tyson?

  That was not what I was trying to look. Would you? Who asked you to comment?

• 8:27Speaker 01

  It is amazing how far we've come and how quickly. Like, I do feel like the, you know, it's not typical. Like, this is the first time in our civilization, possibly, that these, like, cutting-edge research results are disseminated to the public so quickly. Yeah. Like, that's actually something that I love doing at Star Torielist. Like, there was the press release of the new polarized image of the black hole, the center of the Sagittar, the black hole at the center of the Milky Way galaxy. Right. And it came out, and I showed it to my students that day in class and described it to them. Mm-hmm.

• 9:00Neil deGrasse Tyson?

  That's amazing.

• 9:00Speaker 01

  Yeah, and, you know, I can put it on a T-shirt for you and sell it at Star Torielist.

• 9:04Neil deGrasse Tyson?

  The three of us sound a little bit like we're on the porch. Right.

• 9:08Chuck Nice?

  I remember when I can buy.

• 9:10Neil deGrasse Tyson?

  And the young is today.

• 9:11Chuck Nice?

  I remember we had to teletype each other and let them know about the discoveries that we made.

• 9:17Neil deGrasse Tyson?

  Teletype? We had to send the teletype.

• 9:20Chuck Nice?

  Dots and dashes is how we had to tell people about our great, significant discoveries.

• 9:27Speaker 01

  Who started it?

• 9:28Neil deGrasse Tyson?

  Feel a little bit like that. So, before we go on to our Q and A here, let me give your full, dutiful introduction. You're a research associate here in our Department of Astrophysics of the American Museum of Natural History. And you even have a desk.

• 9:44Speaker 01

  Oh, yeah.

• 9:44Neil deGrasse Tyson?

  So we get to count you as a resident research associate.

• 9:47Speaker 01

  Nice.

• 9:47Neil deGrasse Tyson?

  So, continued welcome.

• 9:48Speaker 01

  Taking up space up here.

• 9:49Neil deGrasse Tyson?

  To those ranks. You're also Associate Professor of Astrophysics at the Macaulay Honors College in CUNY, the City University of New York.

• 9:57Speaker 01

  Yeah.

• 9:57Neil deGrasse Tyson?

  And you're in the Faculty PhD Program at the CUNY Grad Center. So you're all in there.

• 10:03Speaker 01

  It's kind of all over the place, yeah.

• 10:05Neil deGrasse Tyson?

  And we see some students of yours that come through here. It's very communal, so.

• 10:09Speaker 01

  I bring my classes here as much as I can.

• 10:10Neil deGrasse Tyson?

  Yes! Didn't I talk to your class one time?

• 10:12Speaker 01

  Yes.

• 10:13Neil deGrasse Tyson?

  Yes.

• 10:13Speaker 01

  Twice, twice, yeah.

• 10:14Neil deGrasse Tyson?

  Yeah, thanks for bringing them by.

• 10:15Speaker 01

  Happening here, yeah.

• 10:16Neil deGrasse Tyson?

  I'm delighted. Just call me. And you're a founding member of B D N Y C. And all those letters are like in subway. I was gonna say, and what line is that?

• 10:27Speaker 01

  Yeah, we are very proud. Oh, there's a whole story behind it.

• 10:31Neil deGrasse Tyson?

  There's no Y. There's no Y.

• 10:32Speaker 01

  There was no Y. So we made up the, um, the Y is kind of, uh, we made it red and white in the, in the center. It's no, there's no Y train, but it's kind of the inverted, um, inversion of the WNYC logo a little bit. But we had a joke going for a little while because, so these brown dwarfs, they, you know, we have the stars that have the letters that go with them. And there's a whole story about that, right? O B A F G K M was, um, that was kind of set into order about a hundred years ago by the Harvard College computers or the Harvard Observatory, um, women who were working as computers there. Annie Jump Cannon took that letters and they were originally done by, uh, the strength of the hydrogen absorption line. But then they were realizing that actually it's a little bit different. It needs to be if we order by temperature, we change up the letters.

• 11:17Speaker 01

  And so that's why it's not alphabetical anymore. Um, but when we started to discover these new.

• 11:20Neil deGrasse Tyson?

  Rather than re-letter them.

• 11:21Speaker 01

  Oh, yeah, yeah, yeah. No, we kept them.

• 11:24Neil deGrasse Tyson?

  They kept them. And just rearranged them. And confusing people for, for the century to fall.

• 11:29Speaker 01

  You call it confusion. I call it job security. Um, and there was a point, apparently there was a bunch of different systems that they were devised and a lot of controversy routed at the time. Um, but since the brown dwarfs were discovered, so the M dwarfs are the coolest and the faintest stars. But for the brown dwarfs, we had introduced new letters for the spectral type. And there are full papers going through the alphabet to say which letter should we use, basically. And so the next ones were L and T that were kind of proposed about the same time. Um, that is, uh, like forever messed up my understanding of the alphabet because it goes M L in stars. Um, but then the next one, we realized, okay, there might be things fainter than these T dwarfs, cooler than these fainter, cooler than the T dwarfs.

• 12:11Speaker 01

  They're going to have different spectral characteristics and things like that. We, um, they proposed that there would be Y dwarfs. And so this was even in my like scientific career in the last 20 years or so. Um, and so for a little while, we had a joke with the B D N Y C logo where there was no Y dwarfs yet discovered. And there was also no Y train that we would have to explain to people from outside of New York City. Then, then the Y dwarfs were actually discovered with the Wide Field Survey Infrared Explorer, this NASA mission in the infrared. Um, and so now we, the joke has been. Become far too long to be actually interested anymore. But we're very proud of our B D N Y C logo with the subway things on there. And I feel like we've sort of upped the game.

• 12:51Neil deGrasse Tyson?

  It's a local community of people of like interest, professional interest.

• 12:54Speaker 01

  Yeah, the three of us started out, myself, Kelly Cruz, who's faculty at Hunter College in CUNY, and Jackie Fahey, who's senior scientist and educator here at A M and H. Yeah. And it was, man, we, over 10 years ago now, something like 12, maybe 14 years ago, we founded B D N Y C. It was one of the first groups that was like led by a bunch of women. You know, like it was still rare back then for kind of the three of us to be working together, leading papers together. We were counting, how many papers could we find with only female authors? For example, we published one with just the three of us. We couldn't find another one that had any more.

• 13:30Neil deGrasse Tyson?

  There were no sole, there were not sole authors.

• 13:32Speaker 01

  That were, that were more than three authors, but only women.

• 13:36Neil deGrasse Tyson?

  It sounds like that back toll test on movies.

• 13:38Speaker 01

  Yeah, I was saying that, the B D N Y C test or something like that.

• 13:41Chuck Nice?

  Sounds like black people in Utah.

• 13:44Neil deGrasse Tyson?

  If you see three in one street, there's something.

• 13:47Chuck Nice?

  You're no longer in Utah.

• 13:55Speaker 01

  It's getting better now, I feel like.

• 13:56Neil deGrasse Tyson?

  You were teleported in that instant.

• 14:00Speaker 01

  Parallel dimension or something.

• 14:02Neil deGrasse Tyson?

  So, before, again, one last thing before we cross over. How does your interest in brown dwarfs take you to an interest in Exoplanet?

• 14:08Speaker 01

  Oh, they're very, very similar. So, the, the interesting thing is that the difference in between brown dwarfs and stars is actually relatively straightforward, relatively. It's the nuclear physics on the inside. Like, it's whether they have enough mass to create the high enough temperature at the core to fuse hydrogen in the helium. Like, that's a big difference, kind of evolutionarily.

• 14:29Neil deGrasse Tyson?

  It's a clean line, too.

• 14:30Speaker 01

  Yeah, it's a, it's a very, like, they either turn on or they don't.

• 14:34Neil deGrasse Tyson?

  Or they didn't.

• 14:35Speaker 01

  Yeah.

• 14:35Neil deGrasse Tyson?

  Okay.

• 14:37Speaker 01

  But for the lower mass things, it's not as clear. And originally, we had a, kind of, we wanted to have a similar definition. And so there was this, this lower mass demarcation that was 13 Jupiter masses. Instead of, between the stars and the brown dwarfs, it's about 75 Jupiter masses. And that was, again, derived in like the 1960s. For the 13 Jupiter masses, we wanted to make this nice clean break between the brown dwarfs and the planets, and so 13 Jupiter masses is the mass-

• 15:05Neil deGrasse Tyson?

  Just to be clear what you're doing, you've turned Jupiter into its own- Into its own measurement. Into its own measurement.

• 15:08Speaker 01

  Oh yeah, we always, oh yeah.

• 15:10Neil deGrasse Tyson?

  I don't know-

• 15:10Speaker 01

  Oh, with the masses, yeah, yeah, yeah.

• 15:11Neil deGrasse Tyson?

  I don't know how common an exercise that is in the rest of society, okay? So, but yeah-

• 15:16Speaker 01

  In New York City, I don't know, yeah, it's one block, but it's one avenue block versus one, you know, street block or something like that. It's whatever miles. But yeah, we do this in astronomy all the time. This is the great, like, astronomers, you know, we say astrophysicist if we want people to be impressed or something like that, we'll take anything and call it one, or like, set it relative to one another to make the math easier, like, we'll do anything to make the math easier.

• 15:37Neil deGrasse Tyson?

  Earth's sun distance? Just one astronomical unit. Well, there you go, one. And how far away is it from the thing? Is 10 of us. Right. Or 5 of us, right.

• 15:45Speaker 01

  Yeah.

• 15:46Neil deGrasse Tyson?

  Right.

• 15:47Speaker 01

  Yeah. So the 13 Jupiter masses, above that, there would be some nuclear fusion going on. So more massive than that, you might fuse a little bit of hydrogen, a little bit of lithium, because that's easier to fuse. Deuterium, which is heavy hydrogen, is also easier to fuse, and so that, easier means it will fuse at lower temperatures. And so above 13 Jupiter masses, there might be a little bit of fusion going on. And then below 13 Jupiter masses, they figured out there's no fusion gonna happen ever. But the thing is that this, like, demarcation doesn't actually make a huge difference in the long term for these things. Like, not in terms of the structure, not in terms of the evolution.

• 16:22Neil deGrasse Tyson?

  So how does it get you interested in exoplanets?

• 16:24Speaker 01

  Yeah, so, the, the, what ends up happening is that the brown dwarfs are actually really similar to the massive exoplanets. And some of these massive exoplanets are things that we found more easily than we found the Earth-like exoplanets.

• 16:39Neil deGrasse Tyson?

  So the size of your party grew?

• 16:41Speaker 01

  Yeah, yeah, yeah. 5, 10 times the mass of Jupiter, we found those exoplanets around other stars even more easily.

• 16:48Neil deGrasse Tyson?

  So you find yourself at the same conferences as these other-

• 16:50Speaker 01

  At fir-, yeah, we, we used to have, kind of, we called them cool stars conferences, and first the brown dwarf people went to the cool stars conferences, but then when the exoplanets got big enough, now there's a ton of different exoplanet conferences that the brown dwarf people go to. We kind of go to both, too.

• 17:04Neil deGrasse Tyson?

  Yeah.

• 17:05Speaker 01

  And we bring our karaoke along, but it's kind of like, yeah-

• 17:08Neil deGrasse Tyson?

  And it's also where collaborations are born.

• 17:10Speaker 01

  Right, yeah, especially the-

• 17:11Neil deGrasse Tyson?

  You can't undervalue-

• 17:13Speaker 01

  And then the planetary science people who have studied the planets and the solar system for so long are like, "What are you guys doing?" Because so much of it, you know, needs like Jupiter, we know in a lot more detail, but there's still a lot of open questions. Saturn, we know in a lot more detail, even Earth atmosphere stuff. Brown dwarf people can learn in order to study these things. Yeah.

• 17:43Chuck Nice?

  Hi, I'm Ernie Carducci from Columbus, Ohio. I'm here with my son Ernie because we listen to StarTalk every night and support StarTalk on Patreon.

• 17:53Neil deGrasse Tyson?

  This is StarTalk with Neil deGrasse Tyson.

• 18:02Neil deGrasse Tyson?

  Let's go jump right in.

• 18:04Chuck Nice?

  Okay, we got questions.

• 18:05Neil deGrasse Tyson?

  Let's do it.

• 18:06Chuck Nice?

  And they are all from our Patreon people and they are all for you specifically. All right, so this is from Laura Fortier, says, greetings from Arizona. Hello, Doctors Rice and Tyson, Lord Nice. I have heard that brown dwarfs and hot Jupiters.

• 18:23Speaker 01

  Yeah.

• 18:24Chuck Nice?

  Are similar. In what ways do they differ? And how are they made when they are clearly separated from a solar system? I heard somewhere that we don't really know how low density stars are even created. Have we learned more?

• 18:38Speaker 01

  Yeah.

• 18:38Neil deGrasse Tyson?

  People doing their homework before they come in on you.

• 18:40Chuck Nice?

  Yeah, they really are.

• 18:41Speaker 01

  So the hot Jupiters are one of these things that like we found around other stars that we haven't found in our solar system. And they, the hot Jupiter is a nice one because it is what it sounds like. It's a Jupiter sized planet, Jupiter mass planet.

• 18:53Chuck Nice?

  That all the other planets think are super sexy.

• 18:58Neil deGrasse Tyson?

  Hot planets, right.

• 18:59Chuck Nice?

  Oh, hot Jupiter in the house. Okay, go ahead.

• 19:02Speaker 01

  Close to its star so that it's irradiated by the star.

• 19:06Neil deGrasse Tyson?

  So it's not hot on its own.

• 19:08Speaker 01

  That's the thing is it's not hot on its own.

• 19:10Neil deGrasse Tyson?

  Oh, so that's a little circumstantial.

• 19:12Speaker 01

  Yeah, and so that's the interesting thing is that these hot Jupiters end up being similar to mass and maybe a similar temperature to a brown dwarf, but for a different reason.

• 19:23Chuck Nice?

  For a different reason.

• 19:23Speaker 01

  Yeah.

• 19:24Chuck Nice?

  Look at that.

• 19:25Speaker 01

  Whether the radiation is coming from the outside or the inside. And so there's similarities, but there's also differences. Yeah, so those are one kind of overlaps.

• 19:32Neil deGrasse Tyson?

  Thanks for clarifying that. And what's the other part of that question?

• 19:33Chuck Nice?

  Um, she said, um. I heard somewhere, we don't really know how low-density stars are created.

• 19:40Speaker 01

  Yeah.

• 19:41Neil deGrasse Tyson?

  So, did they mean low-mass stars, what in low-density?

• 19:46Speaker 01

  Yeah, they can be kind of the same. The interesting thing is that because of the physics going on at the very, very cores, these things kind of plateau in size, and so they do get lower and lower density.

• 19:56Chuck Nice?

  Okay.

• 19:56Speaker 01

  Because the mass decreases while the physical size stays the same. And so they do get lower and lower density, but we talk about them more in terms of their mass. Um, yeah, we don't fully know like how many of the low-mass ones are out there. That's just like counting them. We don't fully know that. We don't really know how they formed or how low the mass can go when it forms like a star does.

• 20:16Neil deGrasse Tyson?

  But why did we invite you to this?

• 20:18Speaker 01

  Job security, yeah.

• 20:21Neil deGrasse Tyson?

  So, let's get to brass tacks. I have a gas cloud out there. There's so many beautiful images of gas clouds.

• 20:26Speaker 01

  Yeah.

• 20:26Neil deGrasse Tyson?

  From Hubble, from especially.

• 20:28Speaker 01

  D W S T, beautiful ones, yeah.

• 20:30Neil deGrasse Tyson?

  So, and we see stars being born. Why weren't those stars born a billion years ago? Why are they being born now? What happened in that gas cloud, ever at any time, to make a star?

• 20:42Speaker 01

  Oh, it depends on what the, yeah.

• 20:43Neil deGrasse Tyson?

  And how does it know to make a high-mass star or a low-mass star?

• 20:45Speaker 01

  Yeah, that, I mean, the universe does, does that. Like, we don't necessarily, you know, we.

• 20:51Neil deGrasse Tyson?

  Now, why'd she get away with that answer?

• 20:53Chuck Nice?

  I was about to say, she actually gave you your answer, but much more succinctly. Which is the universe is under no obligation to make sense to you.

• 21:02Speaker 01

  That's true, yeah. We, that's kind of figuring out, seeing if there's a law. So, there does seem to be a law.

• 21:07Neil deGrasse Tyson?

  We should allow that in the PhD defense, the thesis defense.

• 21:11Chuck Nice?

  Right.

• 21:11Neil deGrasse Tyson?

  So, excuse me, why do you get this? The universe just does that.

• 21:16Speaker 01

  I feel like that is, like, as soon as you can say, like, confidently, "I have no idea," or "I don't know," or "I don't think we can know," like, that's when you're an actual scientist.

• 21:24Neil deGrasse Tyson?

  Yeah, yeah, very good.

• 21:25Speaker 01

  Like, there's a lot of pressure to know the answer.

• 21:28Neil deGrasse Tyson?

  Very important philosophical point.

• 21:29Speaker 01

  The confidence and the uncertainty, like, makes, makes a scientist.

• 21:33Neil deGrasse Tyson?

  Because everybody else is trying to give an answer.

• 21:34Chuck Nice?

  I was gonna say, and that is the difference between, like, I hate to bring it up, but science and religion, and you said somebody BSing you.

• 21:42Speaker 01

  Yeah, I think so.

• 21:43Chuck Nice?

  I said religion, but yeah.

• 21:44Speaker 01

  Oh, I didn't mean to complain those two, but.

• 21:47Chuck Nice?

  But no, it's the truth. Like, you know, religion has an answer for everything.

• 21:51Neil deGrasse Tyson?

  Basically, yeah.

• 21:51Chuck Nice?

  They have an answer.

• 21:52Speaker 01

  Even when one answer contradicts the other answer.

• 21:54Chuck Nice?

  It doesn't make a difference. I gave you an answer, you know, that's, yeah, that's very cool. Or, or I should say, maybe it's like my parents, which were, because I said so.

• 22:02Speaker 01

  Yeah, exactly.

• 22:03Neil deGrasse Tyson?

  That's the ultimate answer.

• 22:03Chuck Nice?

  That's the ultimate answer, because I said so. Uh, that's very cool. All right, well, this is great. That was great. That was really informative. Thank you very much, Laura.

• 22:12Neil deGrasse Tyson?

  And say her last name one more time.

• 22:14Chuck Nice?

  Fortier.

• 22:14Neil deGrasse Tyson?

  Fortier.

• 22:15Chuck Nice?

  Yes, which is not my forte, to pronounce Fortier. Okay, this is Jason, uh, Dorikson, and Jason says, what is the largest dwarf star ever discovered? Oh, look at that, he's, he's going for the jumbo shrimp angle.

• 22:34Speaker 01

  Yeah.

• 22:35Chuck Nice?

  He's going for the jumbo shrimp angle. What is the largest dwarf star that we have actually seen?

• 22:41Speaker 01

  That's a good question. I don't think I can answer that very concretely, and the reason why is because there's more weirdness here that I haven't even really touched upon.

• 22:50Chuck Nice?

  Ooh.

• 22:50Speaker 01

  Which is the fact that when the stars are formed, they then, they kind of form and they start to fuse their hydrogen and helium and they kind of, once they turn on, they stay that way for a while, they get stable.

• 23:01Chuck Nice?

  Right.

• 23:01Speaker 01

  Right? And so they have the same temperature, the same luminosity, um, the same mass for a long time. That's the other thing is that the...

• 23:09Neil deGrasse Tyson?

  Same as, except for the little bit they're losing when they convert into energy.

• 23:12Speaker 01

  Oh, yeah, but it's a tiny, even, even for the small stars, it's a tiny bit of mass.

• 23:16Neil deGrasse Tyson?

  Tiny fraction of the total.

• 23:16Speaker 01

  Yeah, tiny fraction of mass. Um, even for the big stars, the mass doesn't change a huge amount with the nuclear fusion, but the, the big stars have shorter lifetimes and the small stars have longer lifetimes.

• 23:29Neil deGrasse Tyson?

  Yeah. So the low mass ones?

• 23:30Speaker 01

  The low mass ones, we think they can last, and I can't believe we can throw around this number, but for like a trillion years.

• 23:35Neil deGrasse Tyson?

  Yeah, yeah.

• 23:36Chuck Nice?

  Well, you can throw it around because nobody understands what it is.

• 23:40Speaker 01

  Yeah, and probably nobody's gonna be around to prove me wrong.

• 23:42Neil deGrasse Tyson?

  Way longer than the universe has been alive to this day.

• 23:45Speaker 01

  Yeah, yeah.

• 23:46Chuck Nice?

  Wow, right.

• 23:46Speaker 01

  Look at that. But the tricky thing is, so that star becomes stable and kind of doesn't stay, but the brown dwarfs were, will kind of gradually cool and fade over time.

• 23:55Chuck Nice?

  Okay.

• 23:55Speaker 01

  Like, they have this kind of residual heat left over from forming.

• 23:59Chuck Nice?

  Right.

• 24:00Speaker 01

  But then they're just kind of cool and fade. And so as astronomers look, just looking at them, we can't really tell whether we have a young...

• 24:09Speaker 01

  Low mass brown dwarf that's just formed, or an old high mass brown dwarf that's been cooling off for a while.

• 24:16Chuck Nice?

  Because they, because they last for so long, you can't really tell. They look, they look the same.

• 24:22Speaker 01

  The regular, the stars last for a long, long time, but the brown dwarfs cool off.

• 24:26Chuck Nice?

  Right.

• 24:27Speaker 01

  Yeah, and so we have this, we call it the age mass degeneracy. So we don't know if we have a young, low mass thing that's just hot because it's still young.

• 24:36Chuck Nice?

  Right.

• 24:36Speaker 01

  Or an old, high mass thing that's hot because it's a little bit higher mass, but it's been around for a long time.

• 24:43Chuck Nice?

  For a long time.

• 24:43Speaker 01

  Because they're cooling off with time.

• 24:44Neil deGrasse Tyson?

  We have to get her to explain degeneracy.

• 24:46Speaker 01

  Degeneracy, yeah, it's like where you, degeneracy is you can't tell the difference.

• 24:50Chuck Nice?

  That's a lecherous brown dwarf. I know, degeneracy. It has a gambling problem.

• 24:54Neil deGrasse Tyson?

  The brown's worse of today.

• 24:56Chuck Nice?

  Oh, God. It's just not what they used to be.

• 24:59Speaker 01

  I'm never gonna be able to explain my research again. It's so funny, we get so used to using these terms and don't think about the other.

• 25:06Neil deGrasse Tyson?

  So degeneracy is a, it's a mathematical.

• 25:07Speaker 01

  A physical term for us.

• 25:08Neil deGrasse Tyson?

  Physical mathematical, so, so, give it, give it a gamble here.

• 25:12Speaker 01

  There's a couple of different kinds even. So our degeneracy, the age mass degeneracy, is that you don't know one without constraining the other. So it's ambiguity is the colloquial, like that's the.

• 25:22Neil deGrasse Tyson?

  Yeah, two things look alike, but they can be very different from each other, and are just happen to look alike in that moment.

• 25:28Chuck Nice?

  Right.

• 25:28Neil deGrasse Tyson?

  And you can't distinguish one from the other without another, another dimension of data.

• 25:33Speaker 01

  Yeah, we have to be able to measure the mass somehow, or we have to be able to measure the age somehow.

• 25:37Neil deGrasse Tyson?

  You need another data point to break the degeneracy.

• 25:39Chuck Nice?

  Gotcha.

• 25:40Neil deGrasse Tyson?

  And there's another degeneracy.

• 25:41Speaker 01

  Yeah, and then the other degeneracy is like the cores of the objects are partially degenerate, we say. And that's a, like a quantum mechanical thing, where the actual electrons in the atoms get so close together that they fill up the quantum states, and that provides pressure against the mass pushing down.

• 26:00Neil deGrasse Tyson?

  Can't keep squeezing down.

• 26:01Chuck Nice?

  Wow, look at that.

• 26:02Neil deGrasse Tyson?

  That's called degeneracy pressure.

• 26:03Speaker 01

  Yeah.

• 26:04Neil deGrasse Tyson?

  So I'd forgotten we have degeneracy used in two completely different ways.

• 26:07Speaker 01

  Yeah, they are two different, I never thought about that before either.

• 26:10Neil deGrasse Tyson?

  Yeah.

• 26:10Speaker 01

  Yeah, that's such a weird, we speak our own language sometimes.

• 26:13Neil deGrasse Tyson?

  Yeah, yeah, yeah.

• 26:14Speaker 01

  Yeah. And so this high mass, so it's really hard to tell actually exactly how high mass something is. Like nominally, we have the 75 Jupiter mass cutoff.

• 26:22Chuck Nice?

  Right.

• 26:23Speaker 01

  But we also don't know, you know, is it younger or is it old or something like that?

• 26:26Chuck Nice?

  Which will factor into whether or not it is or it isn't, which factors into whether it's the largest brown dwarf we've ever seen.

• 26:34Speaker 01

  Yeah.

• 26:34Chuck Nice?

  I got you.

• 26:35Speaker 01

  Yeah.

• 26:36Chuck Nice?

  Wow, you put all the, damn, that's, that's rough.

• 26:38Speaker 01

  It's weird.

• 26:39Chuck Nice?

  Science is hard. It's rough, man.

• 26:40Neil deGrasse Tyson?

  Science is hard.

• 26:41Chuck Nice?

  Yeah.

• 26:42Neil deGrasse Tyson?

  If you'll just look through a telescope, here's the answer to that question.

• 26:45Speaker 01

  You find new problems as soon as you dig a little bit deeper.

• 26:49Chuck Nice?

  So Jason, the answer to your question is, we don't know. We don't know, man. Sorry.

• 26:54Speaker 01

  How many is that? I think that's, I don't know for the first few questions so far.

• 26:59Neil deGrasse Tyson?

  All right.

• 27:00Chuck Nice?

  Ah, that's pretty cool, though. I love it.

• 27:02Neil deGrasse Tyson?

  But who's it that says, "The only thing I know is that I know nothing"? What's that quote?

• 27:06Speaker 01

  All I know is that I don't know nothing. That's Operation Ivy, but...

• 27:10Neil deGrasse Tyson?

  I think before that, I'm thinking ancient Greece, Socrates.

• 27:14Speaker 01

  Socrates and Operation Ivy.

• 27:17Neil deGrasse Tyson?

  So it'd be Socrates, actually.

• 27:18Speaker 01

  Socrates Johnson.

• 27:20Neil deGrasse Tyson?

  Socrates, it was, "If I know anything at all, it's that I know nothing." I'm paraphrasing.

• 27:26Speaker 01

  So, yeah.

• 27:27Chuck Nice?

  All right, this is Knobble Gobble, and Knobble Gobble says, "Salutations, doctors and Lord. My name is Caleb Noah Getton." Mm-hmm, okay. Noah Getton. Noetken. There you go. "My name is Caleb Noetken." And, oh, thanks, Caleb. He says, "Good luck with that one."

• 27:50Speaker 01

  He even knows.

• 27:51Chuck Nice?

  Son of a gun.

• 27:52Speaker 01

  He knows.

• 27:52Chuck Nice?

  I can't believe you, man.

• 27:55Chuck Nice?

  Then he says, "This is Caleb from Wichita, Kansas."

• 27:58Neil deGrasse Tyson?

  People are, people, I get no respect.

• 28:01Speaker 01

  So you're letting the cat mash on the keyboard that Chuck is gonna have fun with this one?

• 28:05Chuck Nice?

  Yeah, tell me about it. He says, "Since brown dwarfs are sort of an intermediate object between a planet and a star, I was wondering if there was a common trend between mass composition and magnetic field strength."

• 28:19Speaker 01

  Oh, gosh, magnetic fields.

• 28:22Chuck Nice?

  Look at that.

• 28:23Speaker 01

  This is one of those things where if you want to trip up an astronomer, you ask them about dust, or you ask them about magnetic fields.

• 28:29Chuck Nice?

  Right.

• 28:29Speaker 01

  And it's nice because, it's nice because it applies really across any kind of research. We try to ignore it because those things complicate things hugely. So yeah, these things do have magnetic fields, but we actually don't know how the magnetic fields are generated on these stars. We think we know how magnetic fields are generated on the sun because there's this cool thing called the tachocline. And it's like, you know, these moving charges are going to generate the magnetic field. And we think that's where it comes from on the sun. And that tachocline is a border between a radiative zone and a convective zone. So there's energy transport is happening in different ways. But for brown dwarfs, what we think we understand of the structure, and this is all from modeling

• 29:12Speaker 01

  things and understanding how energy transport is supposed to happen, we think at some point they become fully convective. So this is kind of cool. It's like the convection is this big bulk motion of material that happens when you like boil water and stuff like that. So it's relatively familiar to us.

• 29:28Chuck Nice?

  It's like an internal churning?

• 29:29Speaker 01

  Yeah, it's this churning. But instead of the churning only going down part of the way inside the stars, which it does for the higher mass stars, it goes all the way down.

• 29:37Chuck Nice?

  So the two of those together, you have a radiative effect, which is the outward pushing of the star. And then you have the internal churning. And the two of them together, like the earth's core rolling around inside of us makes a magnetic field?

• 29:50Speaker 01

  Well, we don't know for the brown dwarf. That's the thing is that because...

• 29:53Chuck Nice?

  I'm trying to figure it out.

• 29:54Neil deGrasse Tyson?

  All I know is there are a bunch of seven I don't knows.

• 29:58Speaker 01

  So, and we also think the magnetic fields are going to be different across the different types of brown dwarfs.

• 30:03Neil deGrasse Tyson?

  So why don't you call it a somethingy line and not a...

• 30:05Speaker 01

  A tachocline.

• 30:06Neil deGrasse Tyson?

  And not just a dynamo? Or is a dynamo the broader term?

• 30:10Speaker 01

  Dynamo is the broader term that generates the magnetic fields. Yeah. Am I messing up my solar physics? Hopefully not. I could be. Somebody, you know, somebody can get their five cents back. Their five dollars back.

• 30:21Chuck Nice?

  So what is the difference between that and a star? Because we know that's what had happened like in our own sun.

• 30:26Speaker 01

  Yeah, in our own sun, we've kind of got these bigger motions. In the brown dwarfs, we don't know fully where, there isn't this separation between the inner layers. And so we don't know where the magnetic field comes from. But there is a magnetic field. We see spots on the low mass stars and on the brown dwarfs. We see auroras on the brown dwarfs.

• 30:46Neil deGrasse Tyson?

  Spots is good evidence of a magnetic field. On the sun, spots always come in pairs. And one is plus and one is minus.

• 30:50Chuck Nice?

  Oh, I did not know that.

• 30:51Neil deGrasse Tyson?

  Yes, it's a cool fact.

• 30:52Speaker 01

  There's a bright spot that goes along with the dark spot. Yeah, I think the bright spot is harder to see usually.

• 30:57Chuck Nice?

  Look at that. That is the first I've ever heard of that.

• 31:00Neil deGrasse Tyson?

  Yeah.

• 31:01Speaker 01

  And the solar winds that we're gonna see.

• 31:02Neil deGrasse Tyson?

  Here's something else I heard, which is consistent with what you just said. Uh, back in my day, you would accuse someone of, if they're presenting their research, and they say, "The bigger is the effect of a magnetic field in what they describe, the less they know about the subject."

• 31:20Speaker 01

  Yeah.

• 31:21Neil deGrasse Tyson?

  The less they can explain, they put in more magnetic field.

• 31:24Chuck Nice?

  More magnetic field.

• 31:24Neil deGrasse Tyson?

  Which is what accounts for everything that they don't otherwise know.

• 31:27Speaker 01

  It's, uh, it's, magnetic fields are challenging. They're very hard to understand.

• 31:31Chuck Nice?

  Wow, that's really, well...

• 31:33Neil deGrasse Tyson?

  Astrophysically, and in a lab, and we got it, but yeah, yeah.

• 31:36Chuck Nice?

  If we're talking magnets, it's no big deal.

• 31:38Neil deGrasse Tyson?

  Mm-hmm.

• 31:38Chuck Nice?

  Yeah. Wow, well Caleb, that was a great question, man.

• 31:42Speaker 01

  Three I don't know, it's rough.

• 31:43Chuck Nice?

  It doesn't make it, but here's what I'm...

• 31:44Neil deGrasse Tyson?

  I was counting seven, but if it's only three, good, alright.

• 31:46Chuck Nice?

  But this is what I'm loving about the "I don't knows." Every time we don't know something, I learn something.

• 31:51Speaker 01

  Yeah.

• 31:52Chuck Nice?

  Like, something else comes out of it that I've never heard before.

• 31:55Speaker 01

  Yeah.

• 31:55Chuck Nice?

  That's the third time that we've, didn't had an "I don't know," but every, every single time, there's something really cool

• 32:00Speaker 01

  Yeah.

• 32:00Chuck Nice?

  that, that we find out in, in place of "I don't know."

• 32:03Neil deGrasse Tyson?

  And by the way, it's also a measure that the field is very much embedded in its own frontier.

• 32:09Chuck Nice?

  Right.

• 32:09Neil deGrasse Tyson?

  When you're on a frontier, every step you take is into the unknown.

• 32:12Chuck Nice?

  Yeah.

• 32:26Chuck Nice?

  Okay, this is Atticus Thompson. Atticus says, "Hello, Dr. Tyson, Dr. Rice."

• 32:31Neil deGrasse Tyson?

  Is this a, a letter from the Civil War?

• 32:35Neil deGrasse Tyson?

  We need that voice.

• 32:36Chuck Nice?

  "My dearest Dr. Tyson and Dr. Rice, today was an especially difficult day."

• 32:44Neil deGrasse Tyson?

  Signed, Atticus.

• 32:48Neil deGrasse Tyson?

  Is anybody named Atticus today?

• 32:49Chuck Nice?

  Nah.

• 32:49Speaker 01

  Yeah, they're all in Brooklyn.

• 32:51Neil deGrasse Tyson?

  Oh, is that right?

• 32:51Speaker 01

  Yeah, 100% they're all at the playgrounds in Brooklyn right now, I guarantee you.

• 32:55Chuck Nice?

  And you are so right.

• 32:56Neil deGrasse Tyson?

  Wow.

• 32:56Chuck Nice?

  But that's Atticus from Atticus Finch.

• 32:58Speaker 01

  Quite possible.

• 32:59Chuck Nice?

  Yeah, I would, I would think. But anyway, um, he says, "My name is Atticus, and I am nine years old."

• 33:06Neil deGrasse Tyson?

  Oh, he's nine?

• 33:07Chuck Nice?

  Yeah.

• 33:08Neil deGrasse Tyson?

  Okay.

• 33:08Chuck Nice?

  Uh, he says, "I live in Saudi-Daisy, Tennessee."

• 33:12Neil deGrasse Tyson?

  Alright.

• 33:12Chuck Nice?

  Uh, "I want to know if two brown dwarfs..." collided. Do they become a larger brown dwarf? Or would they just become a low mass star? Ooh.

• 33:25Speaker 01

  That is a very good question.

• 33:27Chuck Nice?

  Nine years old? Okay, so Atticus, first of all, you ain't fooling nobody. I don't care if you're nine or not. I know your father helped you with this question.

• 33:34Neil deGrasse Tyson?

  What are you talking about?

• 33:36Chuck Nice?

  You're not fooling anybody, Atticus. I'm Atticus and I'm nine years old. I would like to know.

• 33:43Neil deGrasse Tyson?

  Wait dude, when I was nine, I could have asked that.

• 33:45Chuck Nice?

  You could have asked that question?

• 33:46Neil deGrasse Tyson?

  Oh, yeah.

• 33:46Chuck Nice?

  Okay.

• 33:47Neil deGrasse Tyson?

  Oh, yeah.

• 33:47Speaker 01

  Yeah, I was gonna say you're gonna work for Atticus someday.

• 33:49Neil deGrasse Tyson?

  My interest in the universe was birthed when I turned nine years old.

• 33:52Chuck Nice?

  Okay, alright. Well, Atticus, I take it back. No, I don't.

• 33:57Neil deGrasse Tyson?

  No, no, you wanna get at him? Ask him if he paid the five dollars.

• 34:02Chuck Nice?

  Yeah, but if he's asking questions like that, he might have a job. I'm just saying.

• 34:07Neil deGrasse Tyson?

  Okay, so what happens with when stars collide?

• 34:10Speaker 01

  Yeah, it's gonna depend on their mass.

• 34:13Chuck Nice?

  Really?

• 34:13Speaker 01

  It's not outside the realm of possibility if you have, like, that's just a multiplication or an addition problem, really. If they, if the two brown dwarfs come together and have more than that 75 masses. In theory, yeah, it could ignite hydrogen fusion.

• 34:27Chuck Nice?

  Right.

• 34:28Neil deGrasse Tyson?

  Wait, so the whole star will reorganize?

• 34:30Chuck Nice?

  Right.

• 34:31Speaker 01

  Quite possible. It's something that we haven't, we don't like expect it to happen a lot. I don't think like...

• 34:37Neil deGrasse Tyson?

  It wouldn't be an object with two separate cores, we don't think. Because gravity and friction would bring it together.

• 34:43Speaker 01

  As they get closer together, they would get like torn apart a little bit. And so it would probably, like, if they did coalesce.

• 34:49Chuck Nice?

  And then coalesce again.

• 34:50Speaker 01

  Yeah. We know this happens for, like, the higher mass stars. Because we see that, you know, black hole mergers are what trigger the gravitational waves. We have, you know, stellar mergers, like, it creates more energy and so we have more evidence of it for the high mass stars. So we don't really think about it too much for the low mass stars. Because I think we don't have a lot of super close binaries, like, there's not gonna be a huge amount of energy loss, like, you're gonna need some kind of energy loss to get them to get closer and closer to one another.

• 35:21Neil deGrasse Tyson?

  Somebody has to eat the energy of their orbit.

• 35:22Speaker 01

  Yeah, if they're gonna come together.

• 35:24Neil deGrasse Tyson?

  That's why we don't just... Collide into the sun.

• 35:27Speaker 01

  Yeah.

• 35:27Neil deGrasse Tyson?

  Right now.

• 35:27Speaker 01

  It's a very slow process for any kind of orbital change like that.

• 35:31Neil deGrasse Tyson?

  So, and, and.

• 35:31Speaker 01

  But if it did happen.

• 35:32Neil deGrasse Tyson?

  And blue stragglers are, are similar.

• 35:34Speaker 01

  Yeah, that's all these weird stars.

• 35:36Chuck Nice?

  Wait, what's a blue straggler?

• 35:37Neil deGrasse Tyson?

  You know about the blue straggler?

• 35:38Chuck Nice?

  No. Tell me, yeah, cause.

• 35:39Neil deGrasse Tyson?

  Yeah, yeah, so you look at a cluster of stars.

• 35:42Chuck Nice?

  Right.

• 35:42Neil deGrasse Tyson?

  All born together, so they all should be evolving together as we understand stellar evolution. And there's some stars that are like hotter and bluer than, than anybody else is. And there's a big, in my day, it was a big mystery until someone said, maybe these are two stars that have merged.

• 35:59Chuck Nice?

  Merged.

• 35:59Neil deGrasse Tyson?

  And when you merge.

• 36:00Speaker 01

  So they've become hot again.

• 36:01Neil deGrasse Tyson?

  You get to re-energize your core with fresh material.

• 36:05Chuck Nice?

  Right.

• 36:05Neil deGrasse Tyson?

  So that you will have a, a prolonged life expectancy and you'll come out a little hotter than you're so otherwise supposed to be. They're the late bloomers of the stellar nursery. Well, they got a, they got an injection of new, of new. Had a growth spurt over the summer. Growth spurt. Look at me. Yeah, so they stand out from all the rest of the, the stars. Oh, wow. Blue stragglers, because everyone else has evolved.

• 36:25Chuck Nice?

  Right.

• 36:26Neil deGrasse Tyson?

  Together.

• 36:26Chuck Nice?

  Yeah, cause they all were born together.

• 36:27Neil deGrasse Tyson?

  They were born together and this one got an extra infusion.

• 36:30Speaker 01

  High mass ones especially are bluer to begin with and shouldn't live as long.

• 36:33Chuck Nice?

  Right.

• 36:34Speaker 01

  Yeah.

• 36:34Neil deGrasse Tyson?

  Right, and so these are, these are standouts. So, so I never thought about the brown dwarf. Do you can ignite a brown dwarf that otherwise would have had to live its life?

• 36:42Speaker 01

  Yeah, in theory, I think. In practice, I don't think we see it a lot. We do see, you know, it's hard to tell whether or not things are binaries. Yeah, maybe they, they just come into these stars.

• 36:52Chuck Nice?

  Could be.

• 36:53Neil deGrasse Tyson?

  Maybe they're just a star you're ignoring over in the side and it used to be two brown dwarfs.

• 36:58Speaker 01

  Yeah, would we see evidence of it?

• 36:59Chuck Nice?

  It's hard to. Could very well be.

• 37:01Neil deGrasse Tyson?

  Hidden in plain sight.

• 37:02Speaker 01

  Yeah.

• 37:02Chuck Nice?

  Yeah, look at that. Hmm. Like a, like a. Like a YouTuber that actually crossed over to regular entertainment.

• 37:11Neil deGrasse Tyson?

  What?

• 37:13Chuck Nice?

  Okay, anyway, sorry.

• 37:14Speaker 01

  That's all the.

• 37:15Neil deGrasse Tyson?

  So this is Atticus?

• 37:16Chuck Nice?

  That was Atticus.

• 37:18Neil deGrasse Tyson?

  Atticus, thank you, Atticus.

• 37:19Speaker 01

  That's a very good question, yeah.

• 37:20Chuck Nice?

  That was a great question, Atticus.

• 37:21Neil deGrasse Tyson?

  And you know he's building something in his basement.

• 37:22Chuck Nice?

  Something I don't want anything to know about, but I'm sure the US government does.

• 37:28Neil deGrasse Tyson?

  The power grid dims every, every, every, once a week as he turns on his, his experiment.

• 37:33Chuck Nice?

  All right. Okay, here we go. This is Jimmy Go Lightly. This is Holly's brother. Says, hi, this is James in Charlotte. How does the life-

• 37:42Neil deGrasse Tyson?

  Wait, for those who were not alive in 1964.

• 37:45Chuck Nice?

  Oh, it's still on the, it's still on the movie channel.

• 37:47Neil deGrasse Tyson?

  Is it?

• 37:48Chuck Nice?

  The Turner movie classics. It's a great movie.

• 37:51Neil deGrasse Tyson?

  Yeah, so that was-

• 37:53Chuck Nice?

  What's her face?

• 37:53Speaker 01

  Breakfast at Tiffany's.

• 37:54Neil deGrasse Tyson?

  Breakfast at Tiffany's.

• 37:55Chuck Nice?

  Audrey Hepburn.

• 37:55Neil deGrasse Tyson?

  Audrey Hepburn. She was Holly Go Lightly.

• 37:57Chuck Nice?

  Holly Go Lightly.

• 37:57Neil deGrasse Tyson?

  Based on the novel by Truman Capote.

• 38:00Speaker 01

  Truman Capote, yeah.

• 38:02Chuck Nice?

  Oh, ah.

• 38:04Neil deGrasse Tyson?

  You, you didn't know that?

• 38:05Chuck Nice?

  I did not know.

• 38:06Neil deGrasse Tyson?

  You're learning something every day here.

• 38:07Chuck Nice?

  Let me tell you, that's why I come here.

• 38:08Neil deGrasse Tyson?

  Okay.

• 38:09Chuck Nice?

  Cause I'm stupid.

• 38:13Chuck Nice?

  All right, this is, he says, hey, James in Charlotte here. How does the lifespan of a low mass star compare to the lifespan of other stars such as our sun?

• 38:21Speaker 01

  Yeah.

• 38:22Chuck Nice?

  So.

• 38:22Speaker 01

  These, the brown dwarfs are gonna be around forever.

• 38:24Chuck Nice?

  For a long, long time.

• 38:25Speaker 01

  That's what makes them super useful. Yeah, the sun is gonna stably fuse hydrogen for about 10 billion years. And we're about halfway through that. So if you want something to worry about, like the sun is about halfway through its lifetime. But the brown dwarfs, like we said, are gonna last basically forever. For like our practical definition of forever. Which we use it in kind of a neat way, which is, we call it galactic archaeology. Because some of the low mass stars that we can see now might have been around already since very early on. The high mass stars are gonna have come and gone. But the low mass stars are gonna be around. And one of the interesting things is that-

• 39:03Neil deGrasse Tyson?

  Well, but you can make a low mass star today.

• 39:04Speaker 01

  Yes.

• 39:05Neil deGrasse Tyson?

  And it's be a low mass star. But some of the pool of low mass stars could have been born first.

• 39:10Chuck Nice?

  Right at the very beginning.

• 39:11Neil deGrasse Tyson?

  Right, and they're still alive.

• 39:12Speaker 01

  You might ask, how can we tell the difference?

• 39:14Neil deGrasse Tyson?

  How are you gonna know the difference? Or is it degenerate?

• 39:16Speaker 01

  Yeah. We can, this one, we can tell the difference. And the answer lies in those high mass stars. Because the high mass stars that have been fusing and then exploding have been creating heavier elements. And so the older a low mass star is, the longer ago it was formed, the fewer heavy elements it's gonna have. And so the more recently formed low mass stars are gonna have more of the heavy elements that were created in the subsequent generations of high mass stars, which is kinda cool if you think about it.

• 39:48Neil deGrasse Tyson?

  To get spectra and look at those elements.

• 39:49Speaker 01

  Yeah, so you get the spectra, you look at the elements, and we have a special name for the low, we call it low metallicity, because we call this composition, how many heavy elements are in it, we call that metallicity. The low metallicity stars are called sub dwarfs.

• 40:02Chuck Nice?

  Oh.

• 40:03Speaker 01

  Because they're under the main sequence of stars on this HR diagram.

• 40:07Chuck Nice?

  Okay.

• 40:08Speaker 01

  Yeah, it's a little bit weird, but, and they also tend to be blue in color.

• 40:11Neil deGrasse Tyson?

  I did not know that, sub dwarfs.

• 40:12Chuck Nice?

  That's super cool, man.

• 40:13Speaker 01

  They are fun to study.

• 40:14Neil deGrasse Tyson?

  Because they reveal themselves as their own population.

• 40:17Speaker 01

  Yeah, subsolar metallicity.

• 40:19Neil deGrasse Tyson?

  Got it, got it, okay.

• 40:20Chuck Nice?

  Wow, okay. All right, this is Matt Curtis, and Matt says, hello, doc, doc, lord, uh, Matt here, and Chuck is pronounced Matt.

• 40:27Neil deGrasse Tyson?

  Stop it.

• 40:28Chuck Nice?

  Well, these people, these people are brutal today, man. They are brutal.

• 40:36Neil deGrasse Tyson?

  Chuck is pronouncing Matt.

• 40:40Chuck Nice?

  Coming here from, he says, uh, coming from South Carolina here, uh, given that our space telescope's, uh, technology is improving, and we keep discovering more and more exoplanets, what will it take to directly capture an image of one of them? Deducing their existence, uh, through transit or gravity wobble is great, but what improvements would be required to show an image to the public directly?

• 41:02Neil deGrasse Tyson?

  You wanna see like oceans and continents?

• 41:04Speaker 01

  Oh, he wants, so it depends.

• 41:05Chuck Nice?

  He wants to travel, bro, sure.

• 41:07Speaker 01

  If you wanna, so I like to call, because we do have images of exoplanets.

• 41:10Chuck Nice?

  Right.

• 41:11Speaker 01

  This is an amazing thing.

• 41:12Neil deGrasse Tyson?

  Direct imaging.

• 41:13Speaker 01

  Direct images of exoplanets. It's hard.

• 41:15Neil deGrasse Tyson?

  How many pixels?

• 41:16Speaker 01

  Uh, yeah, a handful. And how many planets? It's like also ten planets, maybe, or something like that. But one of them has stood the test of time, so this is also kinda back in my day of, um, exoplanets. Back in 2008, two directly imaged exoplanets were announced. Um, one was in, uh, around the star Fomalha, which famously had a disk, um, and was a little like... Bright thing in the disk.

• 41:40Neil deGrasse Tyson?

  And that star is of southern hemisphere.

• 41:42Speaker 01

  Yeah, it's a pretty bright star, though. It's got a name, like a star with a, you know, relatively normal name is a star that you can see in the night sky. And then the other one was HR8799, which with a number like that, you can't see to the night sky. But it had three planets detected around it. And both of these, one was done with a Hubble Space Telescope, one was done with a ground-based telescope. But they're amazing discoveries, like, you know, it's, yeah, it's a handful of pixels and it's really fuzzy images. It's like, eh. But the Fowlhot one actually seems to have been a spurious discovery. Like, it's just a clump in the disk that kind of didn't move the way it was expected to move and has since gone away. The HR8799 system, they found another planet even closer in. So there's four planets in the system.

• 42:26Speaker 01

  And you can, over the time, put the images together and watch the planets orbit.

• 42:31Chuck Nice?

  Oh, wow.

• 42:32Speaker 01

  It's beautiful. And so somebody, Jason Wang, I believe his name is, has made gifs that every once in a while go around social media of like a little animation of the images where we can watch planets orbit around a star other than the sun, which I think is just amazingly.

• 42:48Chuck Nice?

  It's crazy. I love it.

• 42:49Speaker 01

  Yeah.

• 42:49Neil deGrasse Tyson?

  But think about it.

• 42:50Speaker 01

  We haven't found that many more.

• 42:52Neil deGrasse Tyson?

  A planet takes years to go around its host star.

• 42:53Chuck Nice?

  Right.

• 42:54Neil deGrasse Tyson?

  You need data over that entire time.

• 42:56Speaker 01

  Decades, yeah, basically.

• 42:57Neil deGrasse Tyson?

  To really get the good.

• 42:58Speaker 01

  Yeah, and these are, this is, the HR8799 system is like a souped-up solar system. It's a bigger star than the sun. The planets are bigger. They're like five to 10 times the mass of Jupiter. And they're all further out than our gas giant planets.

• 43:10Chuck Nice?

  So it's bigger and brighter.

• 43:10Speaker 01

  Yeah, but similar to it.

• 43:12Chuck Nice?

  That's cool, man.

• 43:13Neil deGrasse Tyson?

  Time for like, one more question.

• 43:14Chuck Nice?

  All right, okay, so since we're on exoplanets, let's, let's, let's do Paula Patsova, who says, hello, Dr. Rice, Dr. Tyson, Lord Nice. Paula here from Slovakia. What is the potential of habitability of orbiting planets around a brown dwarf or low-mass stars?

• 43:32Speaker 01

  Yeah.

• 43:33Neil deGrasse Tyson?

  Ooh, good one.

• 43:34Chuck Nice?

  Yeah.

• 43:34Speaker 01

  Yeah, especially the low-mass star. Like, the brown dwarfs, maybe, but they're kind of the extension of the low-mass stars. But the, the low-mass stars, like, we, they might actually be better targets for finding Earth.

• 43:48Speaker 01

  I don't want to say Earth-like, but I'll say Earth-sized planets, at the very least. Because for these indirect methods that were mentioned earlier, the indirect methods, it's easier to see small planets relative to small stars. It's easier to see planets close in to the stars. And so both of those mean that if you look around a small star, it's easier to find Earth-sized planets, and kind of Earth-temperature planets.

• 44:12Neil deGrasse Tyson?

  Okay.

• 44:13Speaker 01

  So they're, because those are going to be closer into the star because it's a cooler star. So it's like a smaller fire.

• 44:17Neil deGrasse Tyson?

  If you're going to have an Earth-temperature, and it's way dimmer, or way less luminous than our sun, you've got to be way closer.

• 44:24Speaker 01

  You can be closer in.

• 44:26Neil deGrasse Tyson?

  To get that same temperature.

• 44:27Speaker 01

  Yeah, to get that same equilibrium temperature. But then it's easier to find that planet with these indirect methods that we use most of the time. And so now, the, those, these small stars have been like really intriguing targets for searching for exoplanets. And so the Trappist I system is a very famous system that was discovered a handful of years ago with seven Earth-sized planets in orbit around that star. And like, something like three or four of them are solidly... Yeah, this one, well, weirdly enough, the star was known before. Trappist is actually the acronym for...

• 45:01Neil deGrasse Tyson?

  An acronym?

• 45:01Speaker 01

  The survey.

• 45:02Neil deGrasse Tyson?

  Oh, okay, okay, the catalog.

• 45:03Speaker 01

  Transiting, blah, blah, blah, blah. But it's a Belgium, the group includes a Belgium observatory. And so it's, they, they, it's like, we call it a backronym sometimes, where they think of the clever term that they want, and then they make up the acronym to go with it.

• 45:16Neil deGrasse Tyson?

  A backronym.

• 45:17Speaker 01

  Yeah, a backronym, yeah, that's a fun portmanteau. So the Trappist I system is super great because a solid three or four of those planets could be in the habitable zone.

• 45:26Neil deGrasse Tyson?

  Right.

• 45:26Speaker 01

  So the habitable zone is where it's the right temperature for liquid water.

• 45:30Neil deGrasse Tyson?

  Goldilocks zone.

• 45:30Speaker 01

  Yeah, yeah, Goldilocks zone. But you still, it doesn't tell you anything about the atmosphere, which you would also need to have liquid water on the surface. And so there's still a lot of unknowns, a lot of what-ifs for those. But the low-mass stars are really exciting targets for Earth-sized exoplanets, at least.

• 45:47Chuck Nice?

  Wow, cool, exciting.

• 45:49Neil deGrasse Tyson?

  All right.

• 45:50Chuck Nice?

  Yeah, that's great.

• 45:52Neil deGrasse Tyson?

  Emily, thank you. You don't come on here often enough. We've got to bring...

• 45:55Speaker 01

  I'm around.

• 45:56Neil deGrasse Tyson?

  We'll just reach out.

• 45:57Chuck Nice?

  I'm right upstairs.

• 45:58Neil deGrasse Tyson?

  Yeah, upstairs.

• 45:59Speaker 01

  Yeah. Walking by.

• 46:01Neil deGrasse Tyson?

  Call me.

• 46:04Neil deGrasse Tyson?

  Well, thank you for bringing back your expertise on this, this, this, this zone of ignorance that existed for so long that finally people are jumping in.

• 46:15Speaker 01

  Yeah.

• 46:16Neil deGrasse Tyson?

  Getting their, getting their hands dirty.

• 46:17Speaker 01

  We've always kind of wondered, right? But now we know for sure, which is amazing.

• 46:21Neil deGrasse Tyson?

  Very cool.

• 46:21Speaker 01

  A lot of the things.

• 46:22Neil deGrasse Tyson?

  All right, all right. Good stuff. All right, well, let me take us out with some reflections. Okay. On this moment. Hmm. In my field, astrophysics, many of us confront people who ask the very sensible question, why are we spending money on anything you're doing when we have all these problems here on Earth? And, okay, before we did all of this, did you not have those problems on Earth? I think you had them long before any of us spent a dime of tax money or any other money trying to understand the universe.

• 47:01Neil deGrasse Tyson?

  What we do know is, what we discover expands our view, not only of the world, but of our place within it. And when I was growing up, there were planets and there were stars. And no one really thought much about, well, how do you get between one and the other in the universe? What does the universe say about that? And then we learned there's an entire field that we didn't even know would exist or could exist, and now does exist, that specializes in the transition between what you are as a planet and what you would become as a star. This is more about our world, our universe, our home.

• 47:44Neil deGrasse Tyson?

  And it could be that this will help us discover life on a planet, around a star, sometime in our future. And so whether or not that specifically puts food on your table, I'll ask you a little differently. I'll say, how much is the universe worth to you? And that's cosmic perspective. Neil deGrasse Tyson here for StarTalk. Cosmic theories, as always, keep looking up.