Debating Pluto's Planethood with Alan Stern

Will Neil take back what he said about Pluto? Neil deGrasse Tyson and comedian Chuck Nice explore planets, dwarf planets, and the Kuiper belt with planetary scientist and principal investigator for the New Horizons Mission, Alan Stern.

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, we're reopening old wounds regarding the status of Pluto. I've got with me in my office Alan Stern, Mr. Pluto himself, and we spend the whole time talking about that little bugger in the outer solar system.

• 0:20Neil 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 here, your personal astrophysicist. Today, we're going to do cosmic queries. And we got Chuck for this, right?

• 0:41Speaker 01

  Oh, definitely.

• 0:43Neil deGrasse Tyson?

  But this is a very special cosmic query.

• 0:44Speaker 01

  It is.

• 0:45Neil deGrasse Tyson?

  Oh, this hits deep.

• 0:47Speaker 01

  Yes, it does. This is the Montague and Capulet's.

• 0:53Speaker 01

  This is the West Side Story of dwarf planets.

• 1:00Neil deGrasse Tyson?

  We got with me my friend and colleague Alan Stern. Alan, welcome back.

• 1:04Speaker 01

  Neil, thank you.

• 1:05Neil deGrasse Tyson?

  To give me some love here. Oh, man. Alan, welcome back to the crib here. We're here at my office at the American Museum of Natural History, and you're one of the world's, I'm not going to say one of, I'm going to say the world's expert on Pluto.

• 1:23Neil deGrasse Tyson?

  Can I say that?

• 1:24Speaker 01

  Wow, you just did.

• 1:27Neil deGrasse Tyson?

  The man, but let's hold Pluto just for a minute. I just want to catch up. I haven't seen him in years.

• 1:32Speaker 01

  I gotta say, this Pluto thing, though, sometimes I feel like I'm typecast like an actor on Gilligan's Island.

• 1:39Neil deGrasse Tyson?

  Oh.

• 1:39Speaker 01

  The only thing people talk about is Pluto.

• 1:42Neil deGrasse Tyson?

  No, no, actually, I don't want to. We'll get to Pluto, because this is a cosmic queries, and so people can't shake Pluto. You know that, people can't shake Pluto.

• 1:50Speaker 01

  Well, it's everybody's favorite planet.

• 1:52Neil deGrasse Tyson?

  Everybody's favorite. So, but let's catch up. What have you been doing? So you are still a vice president at the Southwest Research Institute in San Antonio, part of the space division. Very busy research institute, a lot of different scientific.

• 2:08Speaker 01

  A lot of science, a lot of engineering.

• 2:10Neil deGrasse Tyson?

  Mm-hmm.

• 2:11Speaker 01

  The institute was formed back in the 1940s for the public good.

• 2:15Neil deGrasse Tyson?

  Oh, my gosh.

• 2:15Speaker 01

  And does a lot of federal research, state and local stuff, but also research consortiums for industry, everything from oil and gas.

• 2:23Neil deGrasse Tyson?

  It being Texas.

• 2:24Speaker 01

  Automobiles. Yeah, but electric vehicles, automated vehicles, just thousands of engineers and scientists.

• 2:31Neil deGrasse Tyson?

  Cool, cool. So you've been there for, since you left NASA?

• 2:35Speaker 01

  That's right.

• 2:36Neil deGrasse Tyson?

  Okay. So you may remember, I was at the launch of New Horizons' mission back in 2006. And if I remember correctly, that mission to Pluto was the most powerful rocket with the lightest payload ever, just in combination, so that it could accelerate and get the hell out there before you died.

• 2:59Speaker 01

  Mission accomplished.

• 3:00Neil deGrasse Tyson?

  That's the number one rule.

• 3:02Speaker 01

  Right.

• 3:02Neil deGrasse Tyson?

  In any science project.

• 3:04Speaker 01

  When I was a little kid, I was washing cars and, and baby sitting and doing everything I could think of to buy bigger and bigger model rockets. You have no idea.

• 3:12Neil deGrasse Tyson?

  The kind you would launch in your backyard.

• 3:13Speaker 01

  Yeah, Estes model rockets.

• 3:15Neil deGrasse Tyson?

  Estes, yeah, yeah, yeah.

• 3:17Chuck Nice?

  Oh, wow.

• 3:17Neil deGrasse Tyson?

  Yeah, yeah, yeah. And the biggest one was the Saturn V.

• 3:20Speaker 01

  Right.

• 3:21Neil deGrasse Tyson?

  With like four D engines or something.

• 3:22Speaker 01

  Right, the D engines.

• 3:23Neil deGrasse Tyson?

  The D engines was the biggest.

• 3:25Chuck Nice?

  I only got the one where you stomped on a, a, a balloon and it shot it off with water.

• 3:31Speaker 01

  Yeah.

• 3:31Chuck Nice?

  You know, I couldn't get me further than that.

• 3:33Speaker 01

  That's a starter kit.

• 3:34Neil deGrasse Tyson?

  That's a starter kit.

• 3:35Chuck Nice?

  Yes, exactly.

• 3:35Neil deGrasse Tyson?

  That's lame.

• 3:37Speaker 01

  But then we got the new Horizons, a hundred and, you know, eighty-one foot tall rocket, seventy-foot payload bay, most powerful variant. I got to order every upgrade, you know, I'll take the lightweight nose cone, I would like all five solid rocket motors.

• 3:52Neil deGrasse Tyson?

  Mm-hmm.

• 3:52Speaker 01

  You know, everything to make it go as fast as possible.

• 3:54Neil deGrasse Tyson?

  Right.

• 3:55Speaker 01

  And then we built this little spacecraft the size of a desk, very compact. So this thing was built to launch school bus-sized spy satellites and big communications satellites and things like that. And we more or less took an Atlas V.

• 4:09Speaker 01

  Amped it up with every upgrade you could think of and then launched it basically empty. And of course you got the highest possible burnout speed, so you know Apollo astronauts, three days to the moon.

• 4:19Chuck Nice?

  We're now talking about New Horizons, no longer about your kid Model Rocket, right?

• 4:24Neil deGrasse Tyson?

  Yeah, he transitioned very quickly there.

• 4:27Chuck Nice?

  That was a...

• 4:29Speaker 01

  We're in the big boy rocket.

• 4:30Chuck Nice?

  Yeah, that was a blurry transition. I was like, man, you were a really advanced kid.

• 4:35Speaker 01

  But think about this, Apollo would launch 25,000 miles an hour, three days to the moon. You know, Tom Hanks, right?

• 4:42Chuck Nice?

  Right, exactly.

• 4:42Speaker 01

  Right? New Horizons, nine hours.

• 4:46Neil deGrasse Tyson?

  Right, and didn't you get to the asteroid belt in three days or something?

• 4:50Speaker 01

  Well, not that quick, but we got to the asteroid belt in record time faster than any spacecraft. Just three months.

• 4:55Neil deGrasse Tyson?

  Right, right.

• 4:56Speaker 01

  And Jupiter in a year.

• 4:57Neil deGrasse Tyson?

  Okay, but this also meant by the time you got to Pluto, you were booking.

• 5:02Speaker 01

  Yeah.

• 5:03Neil deGrasse Tyson?

  Right, so...

• 5:03Chuck Nice?

  How do you slow down to even take a picture of Pluto?

• 5:06Neil deGrasse Tyson?

  I mean, in the old days, we got used to flybys.

• 5:09Speaker 01

  Right.

• 5:09Neil deGrasse Tyson?

  And later on, you went into orbit, but this was like the resurrection of the flyby.

• 5:13Speaker 01

  Right.

• 5:14Neil deGrasse Tyson?

  Where you gotta get ready for all your data in just a few seconds.

• 5:16Speaker 01

  And one shot.

• 5:17Neil deGrasse Tyson?

  One shot?

• 5:18Speaker 01

  Once you're gone, you're not making a new turn.

• 5:20Chuck Nice?

  You can't come back, right.

• 5:21Speaker 01

  Get a ride or go home.

• 5:22Chuck Nice?

  So it's just one blurry picture with a sound effect that goes...

• 5:27Neil deGrasse Tyson?

  You hope the picture's not blurry.

• 5:32Neil deGrasse Tyson?

  So anyway, it was a fond memory being there, and so it took how long to get to Pluto?

• 5:38Speaker 01

  It took nine and a half years.

• 5:39Neil deGrasse Tyson?

  Nine and a half years.

• 5:40Speaker 01

  Because it's a long way.

• 5:41Neil deGrasse Tyson?

  And so you just in the Bahamas over those nine years?

• 5:44Speaker 01

  That's all I was doing, yeah, yeah. So we were busy, I mean, you had a lot to do.

• 5:49Chuck Nice?

  When you do that, when is the optimum time, when is Pluto closest to us so that you can intersect it?

• 5:56Speaker 01

  Right, well, we actually, the optimum time in order to get there fast is when it's in a certain orbital position, but it's not closest. It's near closest, but what really matters is it's in the plane of the solar system.

• 6:08Chuck Nice?

  Okay.

• 6:08Speaker 01

  And we got there right at that exact time. In fact, we set a time...

• 6:13Neil deGrasse Tyson?

  What he left out there is Pluto's way the [bleep] out of the plane of the solar system.

• 6:16Chuck Nice?

  Oh!

• 6:18Neil deGrasse Tyson?

  That was implicit and unstated, so at the point where it crosses the plane of the solar system, you don't want to launch something from here and have to leave the plane of the solar system. That's where all your momentum is.

• 6:30Speaker 01

  It takes a lot more fuel, and that slows you down if you have to spin fuel. Climbing out of the plane.

• 6:35Neil deGrasse Tyson?

  Yeah.

• 6:35Speaker 01

  Right.

• 6:36Neil deGrasse Tyson?

  Cause you're already in the plane with Earth.

• 6:37Speaker 01

  Right.

• 6:38Neil deGrasse Tyson?

  And you got, yeah, all of this adds to your favor.

• 6:40Speaker 01

  Right.

• 6:40Neil deGrasse Tyson?

  Okay, continue. I'm sorry for that interruption.

• 6:42Speaker 01

  Where were we?

• 6:45Chuck Nice?

  We took a little detour.

• 6:46Neil deGrasse Tyson?

  We took a little detour, but no, it was nine years. Nine years out, right.

• 6:50Speaker 01

  Yeah, so nine years, but you know, like the Voyagers, which went all the way out to Neptune.

• 6:54Neil deGrasse Tyson?

  Yeah.

• 6:55Speaker 01

  They had 500 people on that project. Scientists, engineers, flight controllers. By the time we did, yeah, the whole way.

• 7:03Neil deGrasse Tyson?

  Yeah.

• 7:04Speaker 01

  And that time, and we did it with 50 people.

• 7:07Chuck Nice?

  Wow.

• 7:07Speaker 01

  And so, the 50 of us were doing the work.

• 7:10Neil deGrasse Tyson?

  You're doing everything.

• 7:11Speaker 01

  Yeah.

• 7:12Neil deGrasse Tyson?

  Doing everything.

• 7:12Speaker 01

  Yeah. And so, we were pretty busy.

• 7:14Neil deGrasse Tyson?

  So, then, with our friend of StarTalk, David Grin spoon, he's been on.

• 7:19Chuck Nice?

  Doctor Funky Spoon.

• 7:20Neil deGrasse Tyson?

  Doctor Funky Spoon, yeah. Yeah, he's, you, you banded together with him to write Chasing New Horizons.

• 7:27Speaker 01

  Yeah.

• 7:27Neil deGrasse Tyson?

  And with the, with this long subtitle.

• 7:29Speaker 01

  Yeah.

• 7:30Neil deGrasse Tyson?

  What, what was that subtitle?

• 7:32Speaker 01

  Inside the epic mission to explore the ninth planet.

• 7:36Neil deGrasse Tyson?

  Did he say ninth planet?

• 7:37Chuck Nice?

  Ninth planet.

• 7:38Neil deGrasse Tyson?

  We'll get back to that.

• 7:39Chuck Nice?

  Oh, boy, here we go.

• 7:40Neil deGrasse Tyson?

  Blood drawn, blood drawn.

• 7:41Chuck Nice?

  Happening already. Shot across the bow.

• 7:44Neil deGrasse Tyson?

  Blood drawn.

• 7:45Chuck Nice?

  Uh oh, here it is.

• 7:46Neil deGrasse Tyson?

  Blood drawn. No, so that's, that's, I mean, that book was needed because Pluto was a big mystery for so many people for so long.

• 7:53Speaker 01

  Well, yeah, and, and this mission was, you know, so much in the public eye.

• 7:57Neil deGrasse Tyson?

  Mm-hmm.

• 7:57Speaker 01

  That really needed to be documented.

• 8:00Neil deGrasse Tyson?

  Yeah.

• 8:01Speaker 01

  Of course, David's an amazing writer.

• 8:02Neil deGrasse Tyson?

  Yeah, yeah, we love, we all love David. We all love David. So also, you, since then, you've been in space, I hear?

• 8:08Speaker 01

  Yeah.

• 8:09Neil deGrasse Tyson?

  You went above the Karman line?

• 8:10Speaker 01

  Wow, we did that on Virgin Galactic.

• 8:12Neil deGrasse Tyson?

  On Virgin Galactic.

• 8:13Chuck Nice?

  Pluto news upset you that much? You're like, I'll show you. I'll go, I'll go investigate it myself.

• 8:20Neil deGrasse Tyson?

  Let me get into space.

• 8:20Chuck Nice?

  I'm proving myself, like, let me go, I'm going to space, damn it.

• 8:24Neil deGrasse Tyson?

  How long, was it like four minutes of weightlessness? About how long is that?

• 8:27Speaker 01

  Four minutes, um, uh, between engine cutoff and reentry.

• 8:30Neil deGrasse Tyson?

  Yeah.

• 8:30Speaker 01

  Yeah, yeah. But a hell of a ride and a tremendous experience to see the planet.

• 8:35Neil deGrasse Tyson?

  So what science were you doing on it?

• 8:37Speaker 01

  Yeah, I was.

• 8:38Neil deGrasse Tyson?

  So it wasn't, you weren't just dry riding?

• 8:39Speaker 01

  Right, right. As much as I wanted to look out the window.

• 8:41Neil deGrasse Tyson?

  Uh-huh.

• 8:42Speaker 01

  Um, I was sent, uh, I'm gonna be doing a NASA mission, um, which is gonna be determining how well the Virgin Galactic spacecraft can be used to do astronomy. On these missions like unmanned sounding rockets.

• 8:54Neil deGrasse Tyson?

  Hmm.

• 8:54Speaker 01

  And on this first mission, I did some physiological experiments, using myself as the guinea pig. And also some practice for the astronomy mission, kind of get the timing of everything down.

• 9:06Neil deGrasse Tyson?

  Okay, so you weren't purely a tourist?

• 9:09Speaker 01

  Right, right.

• 9:10Neil deGrasse Tyson?

  I mean, that's noble, but still sucks. I'd rather just look out the window the whole time.

• 9:14Chuck Nice?

  Right, yeah, just be there for the ride, you know what I mean?

• 9:17Speaker 01

  And you would love it. You should do it.

• 9:18Neil deGrasse Tyson?

  Yeah, I don't, I don't know.

• 9:20Speaker 01

  Hmm, beautiful view.

• 9:22Chuck Nice?

  Yeah, I don't, I'm, uh, listen.

• 9:24Speaker 01

  Why not? Why wouldn't you?

• 9:25Chuck Nice?

  Any, any industry that considers an exploding rocket on the launch pad a success, I'm not doing it.

• 9:32Neil deGrasse Tyson?

  No, no, they don't call it success. They call it an experiment rich in data.

• 9:37Neil deGrasse Tyson?

  That's even worse. That's what the rocket people call it. No, so, so what else you been up to?

• 9:44Speaker 01

  Um, uh, been doing a lot of research, uh, as, you know, as, as a scientist.

• 9:50Neil deGrasse Tyson?

  Right, because your expertise is obviously not just Pluto, your solar system objects of all kinds.

• 9:55Speaker 01

  Yes.

• 9:56Neil deGrasse Tyson?

  Uh, uh, asteroids, comets.

• 9:58Speaker 01

  Yeah, working on things all across the solar system, even the moon.

• 10:02Neil deGrasse Tyson?

  Mm-hmm.

• 10:02Speaker 01

  Um, I'm on Europa Clipper that's going to be launching this year to study Europa and the ocean of Europa, the plumes and the potential for biology.

• 10:10Neil deGrasse Tyson?

  The liquid, the liquid undersurface.

• 10:12Speaker 01

  Yeah, yeah. I'm on the Lucy mission, which is an asteroid mission, just got launched in 2021.

• 10:17Neil deGrasse Tyson?

  Lucy an acronym?

• 10:18Speaker 01

  No, Lucy's a pretty name. It was named after Australia Pithecus Lucy.

• 10:22Neil deGrasse Tyson?

  Oh, that Lucy, which was named after the Beatles, Lucy in the Sky with Diamonds, yes.

• 10:26Speaker 01

  Yeah, and it's all about just like

• 10:27Neil deGrasse Tyson?

  Everything goes back to the Beatles.

• 10:28Speaker 01

  The Australia Pithecus, it's about the origin of our solar system, just like the origin of humans.

• 10:33Neil deGrasse Tyson?

  I see what you did there.

• 10:36Chuck Nice?

  That's amazing, uh-huh.

• 10:37Neil deGrasse Tyson?

  Oh, the Lucy mission, very cool.

• 10:39Speaker 01

  Yeah, yeah.

• 10:40Neil deGrasse Tyson?

  All right.

• 10:40Chuck Nice?

  And what do you, what do you, uh, what data are you gathering to tell you about the origin of this little solar system?

• 10:49Speaker 01

  Well, all these missions contribute to that.

• 10:51Chuck Nice?

  Oh.

• 10:51Speaker 01

  Right? It's, it's a big, uh, uh... Kind of like CSI, right? With hints and clues everywhere and you have to build a whole story up.

• 11:00Neil deGrasse Tyson?

  CSI, the solar system.

• 11:01Chuck Nice?

  And all of a sudden, Alan takes off his glasses and he goes, "Yeah!" Ah, doo doo doo.

• 11:10Speaker 01

  There we go, there we go.

• 11:12Neil deGrasse Tyson?

  Mysteries unsolved, man.

• 11:14Speaker 01

  You know, the Lucy mission is a good example. The asteroids it's going after co-orbit with Jupiter. Neil won't like this, but they orbit in Jupiter's orbit. And there are tens of thousands of them that Jupiter has not cleared. Nonetheless, planet Jupiter has these pockets of Trojans that are leading and trailing. Lucy's the first mission to go explore them. It's thought that these Trojan asteroids.

• 11:39Neil deGrasse Tyson?

  Just to be clear, so these are places in the Jupiter sun system.

• 11:44Speaker 01

  Okay.

• 11:44Neil deGrasse Tyson?

  Where forces of gravity and centrifugal forces balance. So like Lagrangean points.

• 11:48Speaker 01

  Okay.

• 11:49Neil deGrasse Tyson?

  Right, we did a whole thing on Lagrangean points.

• 11:50Speaker 01

  Yes, we did, yeah.

• 11:52Neil deGrasse Tyson?

  So Jupiter has a forward and trailing Lagrangean points and stuff finds itself there.

• 11:56Speaker 01

  Gets trapped in it?

• 11:57Neil deGrasse Tyson?

  Yeah, it's like, it doesn't know where to go because there's nothing pushing it anywhere. And there they go around the solar system.

• 12:03Chuck Nice?

  It's like the Wizard of Poppy Fields. You know, you just wander in and you just stay.

• 12:07Neil deGrasse Tyson?

  Is that what?

• 12:09Chuck Nice?

  Yeah.

• 12:10Speaker 01

  It's a little like that.

• 12:11Chuck Nice?

  Yeah.

• 12:11Speaker 01

  And the objects that are there are thought to be sourced from the same region as a lot of the Kuiper belt objects.

• 12:17Chuck Nice?

  Okay.

• 12:18Speaker 01

  So we're going there so we can compare them to the Kuiper belt objects that New Horizons has explored. And we see if it's really right, if that's part of the story.

• 12:25Neil deGrasse Tyson?

  Just remind me, the leading ones were Trojans. Didn't they have a different name for the trailing ones?

• 12:31Chuck Nice?

  So why do you call them Trojans? I mean, because I'm thinking Trojan horse when I hear Trojan, right? Or is it?

• 12:37Neil deGrasse Tyson?

  There's got to be some origin for why they call it Trojan.

• 12:39Speaker 01

  Yeah, and I'm not a historian.

• 12:41Neil deGrasse Tyson?

  But didn't they call the other ones a different name?

• 12:43Speaker 01

  No, they're just a leading and a trailing cloud.

• 12:46Neil deGrasse Tyson?

  Right, but.

• 12:47Speaker 01

  They're called the Lagrange points four and five.

• 12:49Neil deGrasse Tyson?

  Four and five, L4, L5. But I think only one of these packs are called Trojans and I think the other pack.

• 12:55Speaker 01

  No, they're both called Trojans.

• 12:56Neil deGrasse Tyson?

  You think so?

• 12:56Speaker 01

  They are, I promise you. I think they have individual names, but they're more obscure.

• 13:00Chuck Nice?

  Well, they hide something, that's what we know.

• 13:02Neil deGrasse Tyson?

  They what?

• 13:02Chuck Nice?

  They're Trojans, they're hiding something. We should not trust them, is what I'm saying.

• 13:11Neil deGrasse Tyson?

  So I'm glad we're finally learning more about these objects because they're just sitting out there waiting to be.

• 13:16Speaker 01

  Yeah, and they've been begging for exploration and never.

• 13:19Neil deGrasse Tyson?

  Begging.

• 13:19Speaker 01

  Never. And now the Lucy mission is going to go see almost a dozen of them. Some of them have satellites and we'll visit some of those. And that mission got launched in 2021. We just did a first practice asteroid flyby in the main belt. We're going to do another practice asteroid flyby in 2025.

• 13:38Neil deGrasse Tyson?

  How many people get to say that? It's practice with an whole asteroid. That's amazing, I gotta tell you.

• 13:44Speaker 01

  Because we gotta get it right on those flybys. And then, starting in the late 20s, we'll do a whole series.

• 13:50Neil deGrasse Tyson?

  Late 2020s.

• 13:51Speaker 01

  Late 2020s, we'll do a whole series of flybys of Trojans. Then we'll dive back in our orbit down close to the sun and come back out and go to the other Trojan cloud. Where we'll complete that exploration. If there's an extended mission, we'll do even more. And this will all end in the 2030s. So it's a long-term program of exploration.

• 14:10Neil deGrasse Tyson?

  So just to be clear, once you've established this orbit around the sun going out to Jupiter, it's minimal fuel, right? Because you've already earned this orbit. And so now you're just sort of redirecting it a little bit.

• 14:23Speaker 01

  Right. So the rocket does the initial boost and then we do earth-gravity flybys. We've already done one. We have two more to do to make the whole mission come. And the principal investigator, Hal Levison, is a part of the team that dreamed up the whole geometry and orbital mechanics of how you get so many flybys into just one mission.

• 14:43Neil deGrasse Tyson?

  Right, right. This is the genius of what they gotta do. Like with the Cassini mission to Saturn. It's orbiting Saturn, but it's visiting moons every time. And all these loop orbits, oh, let's check out this other one, do a little adjustment. I mean, it's brilliant that we can exploit the gravitational fields of other stuff. And it's almost diabolical.

• 15:11Speaker 03

  I'm Ali Khan Hemraj and I support StarTalk on Patreon. This is StarTalk with Neil deGrasse Tyson.

• 15:26Neil deGrasse Tyson?

  So, Alan.

• 15:28Speaker 01

  Neil.

• 15:29Neil deGrasse Tyson?

  Alan.

• 15:30Speaker 01

  Neil. It's a pattern.

• 15:32Neil deGrasse Tyson?

  Don't get me started.

• 15:34Neil deGrasse Tyson?

  Okay, get me started.

• 15:35Speaker 01

  Neil.

• 15:36Neil deGrasse Tyson?

  We, uh, we alerted our fanbase that you were gonna be on. And, uh, most of them knew your expertise, but others were, were, were fresh in the, in the room for that. And, we collected questions.

• 15:50Chuck Nice?

  Yes, we did.

• 15:51Neil deGrasse Tyson?

  And these are Patreon members.

• 15:53Chuck Nice?

  Yes, they are.

• 15:54Speaker 01

  Oh, excellent.

• 15:55Chuck Nice?

  These are the people who, uh, keep us afloat.

• 15:58Speaker 01

  Let's see what questions.

• 15:58Neil deGrasse Tyson?

  Yeah, what do you have?

• 15:59Chuck Nice?

  Alright, here we go.

• 16:00Neil deGrasse Tyson?

  I haven't seen them, I haven't, I don't know anything about them.

• 16:02Chuck Nice?

  Let's go with, uh, Sean Ravenfire. Now, I wonder if that's a real name or not. Ravenfire, sounds like, you know, a video game character. I am Sean Ravenfire. I am here to collect the crystals.

• 16:17Neil deGrasse Tyson?

  The crystals?

• 16:20Chuck Nice?

  Alright.

• 16:21Neil deGrasse Tyson?

  Not even the money, right? It's gotta be some thing.

• 16:23Chuck Nice?

  But, your money is meaningless. Give me the crystals. Okay.

• 16:28Chuck Nice?

  Um, Sean says, "Hey, I'm still a little fuzzy on the difference between minor planet, dwarf planet, and planetoid. Can you please explore the differences?"

• 16:38Neil deGrasse Tyson?

  I'm fuzzy too, actually.

• 16:39Speaker 01

  Yeah.

• 16:40Neil deGrasse Tyson?

  Yeah.

• 16:40Speaker 01

  Everybody's fuzzy, because the terms are not, you know, uh, some of them, like planetoid, no one uses.

• 16:45Neil deGrasse Tyson?

  Hmm.

• 16:46Speaker 01

  Um, it is, you hear it very occasionally, no scientist I know uses the term planetoid. I don't even hear-

• 16:52Neil deGrasse Tyson?

  What do they call Thea? Wasn't that a planetoid?

• 16:56Speaker 01

  So, uh-

• 16:57Neil deGrasse Tyson?

  Thea that made the moon.

• 16:58Speaker 01

  The term is planetary embryo. That's the term that's really used.

• 17:03Neil deGrasse Tyson?

  This sounds like a PC thing. You gotta add syllables and add another word.

• 17:06Speaker 01

  But that is the term that's used.

• 17:08Neil deGrasse Tyson?

  Planetary embryo that collided with Earth.

• 17:11Speaker 01

  With Earth, right? To make the Earth moon.

• 17:13Neil deGrasse Tyson?

  I did not know that.

• 17:14Chuck Nice?

  Might that be a planetary spermatozoa?

• 17:19Chuck Nice?

  I'm sorry, you're talking about never.

• 17:20Speaker 01

  But, you know, the embryos are basically the building planets. And there were a lot more of them originally than there are now because many of them combined through collisions to make bigger and bigger objects. Theia ended up spalling material into orbit around the Earth and it collided. It created the moon, but most of Theia ended up in the Earth.

• 17:40Chuck Nice?

  Right.

• 17:41Speaker 01

  And this was a big thing. It was the size of Mars.

• 17:43Neil deGrasse Tyson?

  Yeah.

• 17:43Speaker 01

  Right? Big, big hit, right?

• 17:45Neil deGrasse Tyson?

  Okay, so, uh, so I was just trying to get my vocabulary straight here. So you would call that a planetary embryo, not a planet-

• 17:53Speaker 01

  Toy. Cause no one uses that.

• 17:55Neil deGrasse Tyson?

  Okay.

• 17:55Speaker 01

  So now it's- It's really an archaic.

• 17:57Chuck Nice?

  Is that the same as protoplanet? The planetary embryo?

• 18:00Speaker 01

  Yeah, embryo and protoplanet. Those are interchangeable.

• 18:02Neil deGrasse Tyson?

  Oh, we're good. So protoplanet.

• 18:03Speaker 01

  Protoplanet.

• 18:04Neil deGrasse Tyson?

  Alright, so now, for the longest while, my whole life, growing up, we're about the same age, uh, I knew of this thing called the minor planet circular.

• 18:12Speaker 01

  Right.

• 18:12Neil deGrasse Tyson?

  Which tracked asteroids, basically. So I always thought of asteroids collectively as minor planets.

• 18:19Speaker 01

  Yeah.

• 18:19Neil deGrasse Tyson?

  Is that term still a thing now that we've added vocabulary to the system?

• 18:23Speaker 01

  Sometimes it's used, um, and it's mostly used for the small, kinda potato-shaped, lumpy things in the solar system, not the bigger things.

• 18:31Neil deGrasse Tyson?

  Okay.

• 18:32Speaker 01

  Um, the term dwarf planet, I'm actually very proud of this. I coined the term in 1991 in a research article in the journal Icarus. And it was meant to be-

• 18:42Neil deGrasse Tyson?

  Icarus features planet-based, uh, solar system-based science.

• 18:46Speaker 01

  This is the solar system-

• 18:46Neil deGrasse Tyson?

  Just distinct from the astrophysical journal.

• 18:49Speaker 01

  The first research journal of solar system science.

• 18:51Neil deGrasse Tyson?

  Okay.

• 18:52Speaker 01

  And Carl Sagan was one of the original editors of it, back in the 60s, 70s, when planetary science was being born as a field. And in 1991, I published an article that was about prediction, mathematical prediction. There would be a large number of Pluto-like objects discovered. And I termed them dwarf planets in analogy to dwarf stars and dwarf galaxies and so forth.

• 19:18Chuck Nice?

  Okay.

• 19:18Speaker 01

  And they're meant to be.

• 19:19Chuck Nice?

  Because that word is already in use.

• 19:20Neil deGrasse Tyson?

  It's already in use.

• 19:21Chuck Nice?

  We already have it.

• 19:22Speaker 01

  So smaller, much smaller planets, the ones that are the size of continents. And so, and that term's been used very widely. And we see dwarf planets all across the Kuiper Belt, which is part of the revolution of the Kuiper Belt that we didn't know about till the 90s, is that dwarf planets are more populous than the four terrestrial planets and the four giant planets combined. And there's one dwarf planet orbiting in the asteroid belt called Ceres.

• 19:51Chuck Nice?

  Ceres.

• 19:51Speaker 01

  The largest of the asteroids, which is a mini-planet itself.

• 19:54Chuck Nice?

  Okay, so.

• 19:55Speaker 01

  Right?

• 19:55Chuck Nice?

  Okay.

• 19:55Speaker 01

  Right? Asteroids kind of a zip code. So, you know, it's like a Kuiper Belt object is kind of meaningless. It's just an object in the Kuiper Belt. It's like a zip code. Technically, New Horizons, the spacecraft, is a Kuiper Belt object. For the time being, it's an object in the Kuiper Belt.

• 20:11Chuck Nice?

  Okay.

• 20:12Speaker 01

  Right? So that's just a zip code.

• 20:14Chuck Nice?

  All right. So now, how do you get, how do you get up to the term? Now, I'm not trying to push back here because I'm out of my league between you two. But I want to know, how do you go from being floating rock to planet? Because there's got to be a difference between.

• 20:34Speaker 01

  There's a big difference.

• 20:34Chuck Nice?

  Yeah. You know, one of them is, how do you, how do you make the jump from, you know?

• 20:39Neil deGrasse Tyson?

  Let's start, let's back up. How do you go from potato to dwarf planet?

• 20:43Chuck Nice?

  Oh, yeah, yeah.

• 20:44Speaker 01

  Yeah. So, so the thing about potato-sized objects, so these are things that are the size of counties or mountains. And they're, you know, most of the asteroids that you can look up in a book or that we've flown spacecraft by, they're lumpy and they have irregular shapes. And that's because, that's the shape that, as they were assembled, they just came to rest in when the assembly was finished. And that shape is controlled by the material strength of the object.

• 21:14Chuck Nice?

  Okay.

• 21:14Speaker 01

  The thing is, as objects get bigger and bigger, more and more massive, eventually, they get massive enough that their self-gravity causes them to form into a sphere. And then we call them planets.

• 21:28Chuck Nice?

  Okay.

• 21:28Speaker 01

  Once they're big enough to be a sphere, like Pluto, they're planets. The smallest of them are called the dwarf planets. And then there are larger planets that are Earth or Jupiter size.

• 21:39Neil deGrasse Tyson?

  And those are all spheres.

• 21:41Speaker 01

  There's a continuum. They're all spherical objects.

• 21:44Chuck Nice?

  So sphere is definitely a determining characteristic.

• 21:48Speaker 01

  It's the hallmark.

• 21:49Neil deGrasse Tyson?

  It's one of them.

• 21:49Speaker 01

  It's the hallmark. If you're on Star Trek and they show up somewhere and turn on the viewfinder.

• 21:54Neil deGrasse Tyson?

  Everything is round.

• 21:55Speaker 01

  You see a round rocky something or thing with an atmosphere that's round. You go, oh, there are planets this week.

• 22:00Chuck Nice?

  All right, let me ask you this, both.

• 22:02Neil deGrasse Tyson?

  But did we get through dwarf planet, a planetoid?

• 22:06Chuck Nice?

  Minor planet. So you said there's no minor?

• 22:08Speaker 01

  Minor planets are these little rocky guys. They used to be called, it's an 1800s, 1900s term, minor planet.

• 22:16Chuck Nice?

  Okay.

• 22:17Speaker 01

  Right? And that's kind of a legacy.

• 22:19Chuck Nice?

  All right. So before we move on to the next question, one last question.

• 22:22Neil deGrasse Tyson?

  Asteroid itself is very legacy. Because, who was it? Not Herschel, was it?

• 22:31Speaker 01

  Somebody around 1800.

• 22:33Chuck Nice?

  Some dude.

• 22:34Neil deGrasse Tyson?

  Yeah, he's got his telescope and he sees this dot of light. Like stars are just dots of light. They're so far away, they're just dots of light in the telescope. They see a dot of light, except it's moving.

• 22:45Chuck Nice?

  Right.

• 22:46Neil deGrasse Tyson?

  And it's like, so it looks like a star, but it's not a star. So asteroid.

• 22:51Chuck Nice?

  Ah, star-like.

• 22:52Speaker 01

  Star-like.

• 22:53Neil deGrasse Tyson?

  Right. So, so that's like the biggest misnomer there ever was.

• 22:57Chuck Nice?

  Right.

• 22:58Neil deGrasse Tyson?

  Right. Yes, visually, but if you care what the thing is, and we still call them asteroids, star-like from the Greek.

• 23:06Speaker 01

  Excellent. It's just legacy.

• 23:07Chuck Nice?

  That's legacy. All right. So one last thing, and then we're going to move on because I'm taking up way too much of the Patreon's time. Does composition have anything to do with it? So let's just say that it's round, but it's a bunch, it's an aggregate of just larger objects. But they're not really, they're not condensed. They're not really solid. They're just kind of a congregation.

• 23:33Speaker 01

  We haven't seen anything like what you're describing.

• 23:35Chuck Nice?

  Oh.

• 23:35Speaker 01

  And if you look across the planets of the solar system. Whether they're made of ice, or rock, or they're gas giants, or whatever, uh, they're, they're all, uh, contiguous bodies, not agglomerations like you're describing.

• 23:49Chuck Nice?

  Right.

• 23:49Speaker 01

  Right? They're one big spherical thing, because the gravity crushes everything into that spherical shape.

• 23:55Chuck Nice?

  Okay.

• 23:56Speaker 01

  Right? And they might have a core and a mantle, and a big atmosphere above it, for example. Or they might have a, a core and a mantle and an ocean layer, like Europa.

• 24:05Chuck Nice?

  Right.

• 24:05Speaker 01

  And then a layer, an outer, an outer ice, for example, right? Uh, but, but they're all the same. They're essentially spherical objects. And their shape is driven by the force of their own mass that creates self-gravity.

• 24:19Chuck Nice?

  Okay.

• 24:20Neil deGrasse Tyson?

  You know, nobody say this is, if you had three objects that were each themselves massive enough to be their own sphere.

• 24:27Chuck Nice?

  Right.

• 24:28Neil deGrasse Tyson?

  And you bring them together.

• 24:29Chuck Nice?

  Right.

• 24:29Neil deGrasse Tyson?

  They're making a sphere.

• 24:30Chuck Nice?

  They're making a sphere.

• 24:32Neil deGrasse Tyson?

  Just.

• 24:33Chuck Nice?

  There you go. I got you. That's how, that's how it rolls.

• 24:36Neil deGrasse Tyson?

  That's how it rolls.

• 24:36Chuck Nice?

  That's how it rolls.

• 24:37Neil deGrasse Tyson?

  And we're making a sphere no matter what.

• 24:39Speaker 01

  But the same thing applies when stars collide, and, and they can merge into a still bigger star, into a larger sphere.

• 24:48Chuck Nice?

  Right.

• 24:48Speaker 01

  Right? And, and, uh, it's the same physics.

• 24:51Chuck Nice?

  Okay. All the way through, no matter where you are in the universe.

• 24:53Neil deGrasse Tyson?

  That's the good thing about physics.

• 24:54Chuck Nice?

  There you go.

• 24:55Speaker 01

  Mm-hmm.

• 24:55Chuck Nice?

  That's, that's true.

• 24:57Neil deGrasse Tyson?

  All right, give me some more.

• 24:58Chuck Nice?

  All right.

• 24:58Neil deGrasse Tyson?

  And make this quicker this time.

• 24:59Chuck Nice?

  All right, here we go. This is, uh, this is Andrew Coffey, who says, "Good day, Dr. Tyson, Lord Nice, Sir Alan. I know very little about Pluto, so I'm super excited to hear you talk. I'm hoping you can enlighten me. I'm wondering if celestial bodies like Pluto are only able to form and exist at the extreme distance from the sun? Or could they be orbiting closer, perhaps near a smaller or cooler star? And if so, do we hope finding an exoplanet that is similar, simply too small or too far away from the star, to be seen from the distances involved in our observations?" Thank you. That's two, two parts. One, you know, is the distance from the sun?

• 25:43Speaker 01

  The main part is, is, you know, could you have them close to the sun?

• 25:46Chuck Nice?

  Right.

• 25:46Speaker 01

  In fact, everything we know about the origin of the solar system, um, indicates that Pluto formed at something like half its present distance from the sun. That the solar system is more compact originally. And Pluto and the most of the other dwarf planets of the Kuiper Belt were transported outward with also the small bodies of the Kuiper Belt. But Ceres is another example. Now, Ceres is in the asteroid belt. It's a dwarf planet. Some people think it formed there. Others can argue that it may have come from the Kuiper Belt itself. So, we don't know, but we know that dwarf planets can exist much closer to the Sun.

• 26:24Chuck Nice?

  So, just for clarification's sake, because there are people who may not know, the proximity of when you're talking about asteroid belt, Kuiper belt, the Sun, Pluto, and so how's it go? Where's it go?

• 26:39Speaker 01

  So, the Sun's in the middle of the solar system, right? It's the big Kahuna, right? It controls all the other orbits, right? And then we have the four rocky planets, Mercury, Venus, Earth, and Mars. And then there's an asteroid belt just beyond the orbit of Mars. It stretches for something like 100 million miles outward. Okay? It's big. And then you've got the four gas giants.

• 27:03Chuck Nice?

  That's amazing. Who knew that?

• 27:05Speaker 01

  Then you have Jupiter, Saturn, Uranus, Neptune. By now, you are, Neptune's orbit is 30 times as far away from the Sun as the Earth is, right? And probably 15-ish times as far away as the asteroid belt. Okay? And then beyond Neptune's orbit is this second belt, or disk-like region, called the Kuiper Belt, discovered in the 1990s but predicted back in the 1940s and 50s. And that's where Pluto orbits and a bunch of other dwarf planets and a bunch of much smaller Kuiper Belt objects that are more like asteroids, but much more icy than the asteroids.

• 27:44Chuck Nice?

  Wow. Okay.

• 27:46Neil deGrasse Tyson?

  And if I understand correctly, the Kuiper Belt was a negative prediction.

• 27:50Speaker 01

  What does that mean?

• 27:53Speaker 01

  I didn't learn that in school.

• 27:54Neil deGrasse Tyson?

  Yeah, I think it was a negative prediction. I think Gerard Kuiper published a paper saying that there should be a reservoir of objects, I don't know if he called them comets at the time, a reservoir of objects just beyond the red-blooded planets, and since we don't see any there, then he was making some inference about the early solar system. So, he was using the absence of evidence as an evidence for something else. And then we find stuff there, and we name it after him.

• 28:31Speaker 01

  Yeah, I think it was actually a little different. My recollection of the literature from back then is that there were really two scientists. One was named Kenneth Edgeworth, and the other was Gerard Kuiper. They were both making predictions that beyond the orbit of Neptune, that there was something like an asteroid belt that Pluto orbited in, and that it might contain other planets in it. But it was really beyond the technology of the mid 20th century.

• 29:03Neil deGrasse Tyson?

  Sure. The telescopes couldn't do it, and detectors, yeah.

• 29:06Speaker 01

  And, you know, you had like Clyde Tombaugh squinting at photographic plates. They didn't have the data analysis tools.

• 29:12Neil deGrasse Tyson?

  Clyde Tombaugh, the discoverer of Pluto.

• 29:13Speaker 01

  Yeah, so they didn't have, they had big enough telescopes, but they didn't have sensitive enough cameras, and they didn't have computers to do the painstaking data analysis.

• 29:36Chuck Nice?

  This is AJ Staveley, who says, "Hello, Dr. Tyson, Lord Nice, Dr. Allen, so much respect. I am AJ from Atlanta, Georgia. My question is, what unanswered questions has New Horizons answered, or you have discovered about the Kuiper Belt that researchers like yourself didn't already know, or you were surprised about? Also, is Pluto's dance with Sharon why it appears to be so geologically active? Thank you so much." Mmm. So, a two-part question, but both very cool.

• 30:11Speaker 01

  I'm gonna try to get through all of that.

• 30:12Chuck Nice?

  Yeah, that's a lot.

• 30:12Speaker 01

  So, we found a lot of discoveries.

• 30:14Chuck Nice?

  Okay.

• 30:14Speaker 01

  And you don't have enough time on this show. If I came back two or three more times. All right, let's go top three then. But I want to tell you, a good example is Pluto itself. Okay. Right? We wondered for a long time if its surface would be flat or rugged. Basically, because we knew the surface is made of nitrogen ice and nitrogen ice is structurally weak, it would make a surface that was almost entirely flat. It's so weak that even Pluto's gravity would just flatten it out. Yeah, exactly. You got it. But if the nitrogen is just a frosting on top of a water ice crust, you could have mountain ranges and canyons and craters and all the rugged topography that we actually saw.

• 30:58Speaker 01

  So we answered that question the first day with the first pictures that came back from New Horizons of Pluto. And then, when we went further out into the Kuiper Belt and made the first flyby of a small Kuiper Belt object, we found out how they were born, how they were formed. This was not an accidental encounter. This was intentional. Yeah, you're targeting other Kuiper Belt objects with that trajectory. And this was a goal of the mission. And a billion miles beyond Pluto, we flew by this Kuiper Belt object, Ericoff. No one had ever been to a Kuiper Belt object. And from its shape. Ericoff? Yeah, it means sky in the Powhatan Indian language. Okay, yeah, I knew that. Yeah, of course. Who doesn't know that? Wait, wait, wait, wait. You went to Pluto and then went another billion miles? Yeah.

• 31:40Speaker 01

  And now we're almost twice as far as Pluto now and still exploring. Okay. But when we got to Ericoff, from its geology and geophysics, we could determine that one of the major two theories of how planets get their start, how planetesimals, the seeds of planets form, was wrong, and the other theory was right. And we found that, essentially, that these little planetesimals, the seeds of planets, form very gently. And through a very slow, local accretion process.

• 32:11Chuck Nice?

  Mm-hmm.

• 32:12Speaker 01

  In which they can. Rather than. Collide at high speed. Rather than collisions, interesting. And there were decades in which computer models were warring and in one fell swoop, New Horizons settled that with the data on air craft.

• 32:25Chuck Nice?

  Beautiful.

• 32:25Speaker 01

  It showed you pick one out of a bag and look at it up close and you could tell one theory's right, one theory's wrong. Beautiful, so it means they just kinda gather.

• 32:33Chuck Nice?

  Everybody comes together.

• 32:34Speaker 01

  Just come together. They start off in little pockets and the little pockets end up with little material, boulders and hills. Very cool. And mountains that collide with one another very gently and just, just stick due to self-gravity and build up a lumpy thing, not big enough to be a round thing.

• 32:53Chuck Nice?

  Right.

• 32:53Speaker 01

  Just a lumpy thing.

• 32:54Chuck Nice?

  Right.

• 32:55Speaker 01

  And tell, tell us about the Pluto Sharon dance? Oh yeah, that was the other question. So the question was whether Pluto's intense geologic activity could be due to that. And it turns out not. Due to? To that dance. The gravity.

• 33:08Chuck Nice?

  The gravity.

• 33:09Speaker 01

  To the mutual gravity of Pluto and its big moon. Mm-hmm. They're in a very special state called tidal equilibrium. Turns out that because of that equilibrium, all those forces that might heat Pluto or make that geology go are long gone. And, and. Tidal equilibrium, you mean double tidal lock? Yeah. Yeah. That's right.

• 33:29Chuck Nice?

  There we go, we know what that is.

• 33:32Speaker 01

  But that can't be the cause of Pluto's geology. It's gotta do something else.

• 33:35Chuck Nice?

  Okay.

• 33:36Speaker 01

  All right.

• 33:37Chuck Nice?

  Interesting.

• 33:37Speaker 01

  Very good.

• 33:38Chuck Nice?

  All right.

• 33:38Speaker 01

  And that might have to do with the ocean that we think is inside of Pluto, just like Europa. So the ocean, ocean is not rigid, so it can shake things up. Right. Well, it's also, as it freezes, releasing heat. Oh yeah. Called latent heat, you know about that. Yeah, yeah, yeah, yeah. And that can power the geology. Physics 101.

• 33:54Chuck Nice?

  So wait a minute.

• 33:55Speaker 01

  What?

• 33:55Chuck Nice?

  Okay, I failed Physics 101.

• 34:00Chuck Nice?

  Freezing gives off heat?

• 34:02Speaker 01

  It does. It, it releases heat.

• 34:04Chuck Nice?

  Mm-hmm. All right. Okay. All right. I'm, I'm gonna tell you right now, I've been on this earth.

• 34:15Chuck Nice?

  For a little while now. That's the first time I ever heard somebody say freezing gives off heat, so I'm just gonna call bullshit.

• 34:23Neil deGrasse Tyson?

  No, no, no.

• 34:25Chuck Nice?

  You can drive.

• 34:25Neil deGrasse Tyson?

  No, I got one for you.

• 34:26Chuck Nice?

  I'm joking, I'm joking.

• 34:27Neil deGrasse Tyson?

  I got one for you.

• 34:27Chuck Nice?

  No, I'm serious.

• 34:28Neil deGrasse Tyson?

  No, no, I got one for you, I got.

• 34:29Chuck Nice?

  Go ahead, go ahead.

• 34:30Neil deGrasse Tyson?

  Are you seated? Okay.

• 34:31Chuck Nice?

  I'm seated.

• 34:32Neil deGrasse Tyson?

  Let's look at the other side. So you have water on the stove.

• 34:35Chuck Nice?

  Right.

• 34:36Neil deGrasse Tyson?

  You're heating it.

• 34:36Chuck Nice?

  Right.

• 34:37Neil deGrasse Tyson?

  And it's, and you, as you heat it, the temperature rises, correct?

• 34:40Chuck Nice?

  Correct.

• 34:41Neil deGrasse Tyson?

  Okay, then it hits, what temperature?

• 34:43Chuck Nice?

  Um, boiling point.

• 34:45Neil deGrasse Tyson?

  Two hundred and twelve.

• 34:46Chuck Nice?

  Two twelve.

• 34:46Neil deGrasse Tyson?

  You keep heating it.

• 34:47Chuck Nice?

  Yes, you do.

• 34:48Neil deGrasse Tyson?

  Where does the heat go?

• 34:48Chuck Nice?

  Wait a minute.

• 34:49Neil deGrasse Tyson?

  It does not raise the temperature.

• 34:50Chuck Nice?

  It does not raise the temperature.

• 34:51Neil deGrasse Tyson?

  Correct.

• 34:51Chuck Nice?

  It turns into steam.

• 34:53Neil deGrasse Tyson?

  So the, the, the heat simply goes and changes it from liquid to gas.

• 34:57Chuck Nice?

  So the molecular change is.

• 34:59Neil deGrasse Tyson?

  Itself.

• 35:00Chuck Nice?

  That itself, okay.

• 35:01Neil deGrasse Tyson?

  Okay, so now you go the other direction.

• 35:03Chuck Nice?

  Holy crap!

• 35:03Neil deGrasse Tyson?

  Yeah, so now you go the other direction.

• 35:05Chuck Nice?

  Yes!

• 35:06Neil deGrasse Tyson?

  Now, you're gonna, you're gonna suck energy out of the water, the temperature drops.

• 35:10Chuck Nice?

  Right!

• 35:10Neil deGrasse Tyson?

  And then there's a point where you're still sucking energy, the temperature doesn't drop.

• 35:13Chuck Nice?

  Aw, man.

• 35:14Neil deGrasse Tyson?

  And all does is change state.

• 35:15Chuck Nice?

  Change the molecular state.

• 35:17Neil deGrasse Tyson?

  Right.

• 35:17Chuck Nice?

  Damn, that's. Where was he when you took that physics?

• 35:22Chuck Nice?

  Tell me about it. That might have done a lot better.

• 35:25Neil deGrasse Tyson?

  You might have.

• 35:25Chuck Nice?

  Had I had Neil.

• 35:26Neil deGrasse Tyson?

  Yeah, so we call it latent heat, there's, there's terms for it in physics.

• 35:30Chuck Nice?

  Latent heat?

• 35:30Neil deGrasse Tyson?

  It, it's really physics one oh one.

• 35:32Chuck Nice?

  Hi, how y'all doing? I'm latent heat. Hey!

• 35:40Chuck Nice?

  Okay.

• 35:41Neil deGrasse Tyson?

  All right.

• 35:41Chuck Nice?

  You've personified latent heat.

• 35:43Neil deGrasse Tyson?

  Yeah, yeah, that's right.

• 35:44Chuck Nice?

  I will never get this out of my head.

• 35:45Neil deGrasse Tyson?

  I know, right, you can't do.

• 35:47Chuck Nice?

  Oh, God.

• 35:48Neil deGrasse Tyson?

  Also, Sharon, just in the, in the traditions of the field, Pluto is Roman, god of the underworld.

• 35:57Chuck Nice?

  Right.

• 35:57Neil deGrasse Tyson?

  And moons have traditionally been, not in all cases, but in many cases, traditionally named for Greek characters in the life of the Greek counterpart to that Roman god.

• 36:08Chuck Nice?

  Okay.

• 36:08Neil deGrasse Tyson?

  And that way, both, there's an homage to both cultures.

• 36:11Chuck Nice?

  You get both cultures.

• 36:12Neil deGrasse Tyson?

  Right, so, so Pluto's counterpart in Greek is what?

• 36:16Chuck Nice?

  Uh, what's his face, the underworld?

• 36:17Neil deGrasse Tyson?

  Hades.

• 36:18Chuck Nice?

  Hades.

• 36:18Neil deGrasse Tyson?

  Yeah, Hades, okay. It's also the place, but it's also the...

• 36:20Chuck Nice?

  Yes.

• 36:21Neil deGrasse Tyson?

  Okay, and the ferryboat driver to take you across the River Styx is named Sharon.

• 36:27Chuck Nice?

  Sharon.

• 36:27Neil deGrasse Tyson?

  Yes.

• 36:28Chuck Nice?

  Uh, there you go.

• 36:29Speaker 01

  That's where that came from.

• 36:29Neil deGrasse Tyson?

  Sharon!

• 36:30Chuck Nice?

  Okay, here we go. Greetings, Dr. Tyson and, uh, Dr. Alan. Um, I'm Jasmine from the wine country here in Northern California. I'm very curious, uh, what's the big deal about Pluto? Does it even really matter if it's a planet or not? Why all the fuss over this icy rock at the edge of our solar system?

• 36:49Neil deGrasse Tyson?

  Oh, yeah.

• 36:51Chuck Nice?

  Look at that, oh.

• 36:53Neil deGrasse Tyson?

  Can I venture a guess that it's been with us so deep in our culture that it's hard to shake any adjustments to those?

• 37:02Speaker 01

  Well, that's, that's, that's a guess, but as a scientist, uh, the real reason is that Pluto is the archetype. It's, it's, it's the heralding body of this whole new type of, of, of planet. The dwarf planets that we've discovered in the outer solar system. They're active, they have moons, they have atmospheres in some cases. And, uh, far from being a rock, it's a big spherical thing.

• 37:26Chuck Nice?

  Right.

• 37:26Speaker 01

  Right? And, and, uh, that's why we call it a planet. We don't know what else to call it.

• 37:31Chuck Nice?

  There you go. All right.

• 37:32Neil deGrasse Tyson?

  Planet modified by the word dwarf.

• 37:34Chuck Nice?

  Right.

• 37:34Speaker 01

  Like giant. Giant planet for Jupiter.

• 37:37Chuck Nice?

  A gas.

• 37:37Neil deGrasse Tyson?

  Yeah, yeah, which, I don't have a problem. I mean, that's, in fact, where we agreed, okay? And one of the correspondence I got back when I was pilloried by third graders. Cause here, people, I don't have to give the backstory here.

• 37:52Speaker 04

  Dear Dr. Tyson, why are you so mean?

• 37:56Speaker 01

  Well, what's really sad is not that he's mean, it's just that he's wrong.

• 38:03Speaker 04

  Oh, snap! What happened?

• 38:06Chuck Nice?

  Geek fight.

• 38:09Neil deGrasse Tyson?

  No, no, it's like.

• 38:10Speaker 01

  So you failed your freshman physics. He did great at all that. He did all the way up through PhD, but he's failed his planet test.

• 38:17Neil deGrasse Tyson?

  No, so we have the word paper, right? And we have construction paper, corrugated paper, toilet paper.

• 38:25Speaker 01

  Right.

• 38:25Neil deGrasse Tyson?

  A card, stock paper.

• 38:27Speaker 01

  Cardboard, right.

• 38:28Neil deGrasse Tyson?

  Right, so this paper is a, is a very broad category. And then we modify that with whatever is the next word. And we know exactly what anybody's talking about.

• 38:36Speaker 01

  Okay.

• 38:37Neil deGrasse Tyson?

  So I, I don't have any problem with that. Just let, so it was, I've always felt there's been a shortage of vocabulary to. So in other words, let me hear, I'm sure we agree here. Jupiter and Earth should not be called the same object in orbit around a star.

• 38:57Speaker 01

  I disagree.

• 38:58Neil deGrasse Tyson?

  No, yeah, they're rounded, but one is huge in gases and, and, and Earth is smaller than storms on Jupiter's weather system. So wouldn't it be cool if we just had a different vocabulary? So that when I use the word, you know exactly what I was talking about. Right now, if I just say, I discovered a planet orbiting a star, is it gaseous? Is it rocky? Is it large? Is it small? Is it, and I have to ask 20 questions just to understand what anybody's talking about.

• 39:22Speaker 01

  That's the cool part of science. And as.

• 39:24Neil deGrasse Tyson?

  No, that's a weakness of science.

• 39:26Speaker 01

  As a planetary scientist, you know, planet is part of the term of what our field is all about. Right? And so we know what planets are. They are the, they are the things, um, the central objects of our field. And they are the large things that orbit stars. And they range from the smallest large, they, they know they're large when they become round and gravity dominates. And from the dwarf planets all the way up to the giant planets. That's a continuum of objects we all call planets.

• 39:55Neil deGrasse Tyson?

  Yeah.

• 39:56Speaker 01

  And planetary scientists agree on that. And in the planetary science research literature, there's no debate.

• 40:01Neil deGrasse Tyson?

  I, I don't have a problem. I just, I'm a big fan of words. I have six dictionaries on my shelf over there from different eras and I watch words come and go. I'm just saying, if you have to modify the word planet in order to know what someone is talking about. That's a clarion call for another word. A word yet to be invented that captures both of those simultaneously. And so it's a shortcoming of the lexicon. That's all I'm saying. Look at me, don't blame me.

• 40:29Chuck Nice?

  You see how he's looking? Wow.

• 40:31Speaker 01

  I'm telling you.

• 40:32Chuck Nice?

  Did you see that face?

• 40:33Speaker 01

  I'm telling you, by that, for example, we have different kinds of human beings, short ones, tall ones, skinny ones, big ones, right? We have North Americans and Europeans and South Americans, and that doesn't mean we need a new term for human beings. It just means adjectives help in the English language. And there are all kinds of ways to add descriptors to planets, to stars, to galaxies. We do that, all through science, right? And we gotta get over these small number fears, right? I mean, if we're gonna have only eight planets, Neil, I'm afraid the periodic table's gotta stop at beryllium. You know, the periodic table has 119 elements in it, right? We're not afraid of a large number of those.

• 41:16Neil deGrasse Tyson?

  No.

• 41:17Speaker 01

  Just like we're not afraid of having 50 states, right? Or countless numbers of stars and asteroids and everything else.

• 41:22Chuck Nice?

  We only have 49 states. Texas is not a state.

• 41:25Speaker 01

  By nature.

• 41:26Chuck Nice?

  It's its own country. Just ask anybody from there.

• 41:30Speaker 01

  I've been to restaurants, called Texas is a planet.

• 41:36Speaker 01

  So we get used to big numbers of planets now that we see them around stars and lots of them in our own solar system.

• 41:40Neil deGrasse Tyson?

  Doesn't Star Trek have a much more nuanced system and nomenclature for planets?

• 41:46Chuck Nice?

  Yeah, cuz they classify all planets.

• 41:48Speaker 01

  Star Trek is fiction. We're talking about fact.

• 41:51Neil deGrasse Tyson?

  No, no, but let's imitate fiction.

• 41:52Chuck Nice?

  Okay, Alan, I was on your side until that statement right there. How dare you, son?

• 42:01Neil deGrasse Tyson?

  Send him away, one factor one. No, so I'm just saying, there's a term, a succinct term that references, is it an oxygen-nitrogen planet? There's a gravity. There are ways of folding that into the term. So that someone says, I just...

• 42:17Speaker 01

  You don't mind Star Trek having lots of kinds of planets?

• 42:19Neil deGrasse Tyson?

  Yeah.

• 42:20Speaker 01

  See? It's just fine.

• 42:21Neil deGrasse Tyson?

  I'm all in.

• 42:22Speaker 01

  We got ocean worlds, right?

• 42:23Neil deGrasse Tyson?

  I'm all in.

• 42:24Speaker 01

  And we got volcano worlds, and we got biologically active worlds and sterile worlds. It's all good.

• 42:30Neil deGrasse Tyson?

  All in.

• 42:30Speaker 01

  There you go. Adjectives rock, don't they?

• 42:32Neil deGrasse Tyson?

  On it. Alan, great to have you back on. Thanks so much, Neil. Okay.

• 42:37Chuck Nice?

  It's a pleasure.

• 42:37Neil deGrasse Tyson?

  All right, good, thanks. We're done here. Oh my gosh, but we're really not done.

• 42:42Chuck Nice?

  No, we have, we have solved nothing. We, we must do it again because nothing has been resolved.

• 42:49Neil deGrasse Tyson?

  All right. So, this has been StarTalk, the Pluto Cosmic Queries Edition, if I may call it that. We're gonna have to get Alan back because we just barely scratched the surface here. Anyhow, thank you, Alan, longtime friend and colleague. Thanks so much. Chuck, always good to have you. Pleasure. All right, Neil deGrasse Tyson here, your personal astrophysicist, as always. Keep looking up.