Dean chats with Mike Brown, the so-called "killer of Pluto," about why Pluto was demoted from planet status and how people have reacted to the change. And about a new planet that might take it's place!
Send us your thoughts at lookingup@wvxu.org or post them on social media using #lookinguppodcast
Additional resources referenced in this episode:
- The Five Stages of Grief, Sprouts, YouTube
- What is a Planet?, PBS
- Michael Brown, Pluto Killer at THiNK 2011, telhelkatv, YouTube
EPISODE TRANSCRIPT:
Looking Up is transcribed using a combination of AI speech recognition and human editors. It may contain errors. Please check the corresponding audio before quoting in print.
Dean Regas: Okay, don't hold back. How many of you out there are still mad about what we did to Pluto? You know, kicking it out of the planet club. I understand these feelings are still raw. All I can say is, after listening to this episode, you'll feel a lot better about the whole thing, and maybe, possibly, Be a little closer to acceptance.
From the studios of Cincinnati Public Radio, I'm your host, Dean Regas, and this is Looking Up, the show that takes you deep into the cosmos or just to the telescope in your backyard to learn more about what makes this amazing universe of ours so great. My guest today is astronomer, Professor of Planetary Astronomy at Caltech, and the self-acclaimed planetologist. Killer of Pluto Mike Brown.
Now, I do want to say first off that I was against the demotion of Pluto initially. I was with you guys. Basically, what I found was that I went through the classic five stages of grief.
[Archival Audio]: Losing something we love or someone who is dear to us can cause us a lot of pain. To accept the loss and overcome the pain, we often go through five stages of grief. Grief, denial, anger. Bargaining. Depression. And finally, acceptance.
Dean Regas: I wrote a book on the subject called, How to Teach Grown Ups About Pluto. Because so many adults have a, hmm, how do I put this? Childish notion of what Pluto really is like. And so, I wrote the book for kids to walk their traumatized adults through the loss of a planet.
And I got the reactions from people across the spectrum. What I found was that they reacted to it. Along the same lines of the five stages of grief. In fact, I put the five stages of grief illustrated in the book, by the way, which took a lot. I had to convince the publisher it was; it was tough. They're like, why are we going to put this in the kid's book?
I was like, trust me, it's funny. But when I post, I have this new book. People came out with the whole gamut.
First, denial. No, Pluto's still a planet. Then, anger. Oh, you guys think you're so smart, kicking Pluto out. Bargaining, number three. Okay, Pluto should still be a planet, but we can add the other things that they found, like Eris and Haumea and MakeMake. And then, depression. Because, people are like, oh, it's been 18 years, I haven't got posts on social media with sad puppy dog eyes, like, they're completely depressed, they've Lost all hope finally there is of course the post that we're accepting of this and finally you get to accept it So that's my goal is that wherever you are on that spectrum from the five stages grief I want you to move one or more to the right just a little bit more.
We'll get to acceptance We'll get there. One of these days.
Mike Brown: I am Mike Brown, and I am the dictator of the solar system.
Dean Regas: So, I know you're really tired of the whole Pluto planethood debate, but I think it's safe to say that you had the most to gain from Pluto staying a planet because, you know, logically, several of the objects you found would then also become planets.
You would be the greatest planet discoverer in the universe. So why did you say Pluto should not be a planet?
Mike Brown: Because I didn't want to feel fraudulent. These things that I discovered that are, you know, Eris and Haumea and MakeMake, these things people may have heard of, they're these icy bodies of about the scale of Pluto.
They would have all been planets. I think I would have instantly had three planet discoveries to my name versus only one to anybody else. So, you're right. Greatest. planet discoverer of all time, except that it just felt wrong. You know, planet discoveries, when, when, when Herschel found Uranus by noticing this thing in the sky, or when, when Le Verrier found Neptune by calculating a gravitational perturbation, these were major discoveries.
parts of the solar system. These things that I found are really interesting and, and fascinating objects to study. But if you took them out of the solar system, the solar system would be the exact same solar system minus one kind of small body. And Pluto is the same way. It just, it just didn't make sense to put them in the same category as these eight major planets of our solar system.
Dean Regas: Well, I hate to tell you, but people are still mad about this thing, and I was a Pluto defender for a little longer than I'd like to admit, but you personally convinced me. You said, uh, well, Dean, you know, I assume you're still mad about what we did when we kicked the asteroids out in the 1850s. You remember that?
And I was like, tell me what? And you said, well, you know, we kicked out planets before. We've done it before. We did it in the past.
[Archival Audio]: Did you know that in 1801, a new planet was discovered orbiting between Mars and Jupiter? They called it Ceres, and then they looked some more, and they found another planet, and another, and another.
The count of planets in the early 1800s was greater than it is today. Thirteen planets in the solar system! And they kept looking, and the numbers kept growing, and they were running out of names. And they realized Rather than counting new planets, they had discovered a new swath of real estate in the solar system called the Asteroid Belt.
Dean Regas: And if you're still mad about Pluto, you should be mad about Ceres, right? And I was like, oh, my gosh, I never thought of that. But I also find your approach to it very unique because, I mean, you have a book out there called How I Killed Pluto and Why It Had It Coming. I mean, the title alone says something, but is this a serious discussion?
Does it matter or do you just love having fun with this?
Mike Brown: You know, it is true. I've been, been known to go around and like, uh, X out Pluto when you see, you know, a solar system include Pluto in it. And it, it's a fun discussion to have, but let me, let me tell you why I think it actually matters. This naming is that first step in, in classification and classification is what scientists do in their first step towards understanding and explaining.
And if you try to explain. the solar system, when you've classified Pluto as a planet and, and we can add in Eris and MakeMake and Haumea, and you explain all these other objects away. There is no explanation because it's a weird, nonsensical classification. It's the same thing like if you're looking at birds, you can classify birds by many different things.
You could classify them by, by color. And explaining the classification of bird by color, it doesn't really teach you much about birds. If you explain by, you know, these are birds that hunt, these are birds that eat worms, these are birds that swim in the ocean, you know, you're actually learning something about birds that way.
And I think, I think that getting the classification right is an important part of being able to understand what you're seeing. So, I think it does
Dean Regas: matter.
One of the things that you've mentioned in your talks and your books is that with all this attention on Pluto It's kind of lost as to what the new discoveries are made, you know, so these new worlds out there that are found What are your favorites I guess as you look at these out there?
Mike Brown: One of my favorites might be Haumea.
Haumea is it's kind of the shape of a deflated squashed football and on the on the long axis of it is about the same size as Pluto. And then the shorter axes are maybe like half the size of Pluto. It rotates end over end every two hours. It's spinning super quickly. And the reason it's spinning so fast, we now know is because back in the early part of the solar system, it got smashed by another object, kind of at an oblique angle, and that led it to spinning like this.
When that happened, Chunks of it went flying off into space. Um, we've now found those chunks. We can, this is kind of the Humpty Dumpty object. We're trying to put back together again. And two of the little chunks are, are moons that now go around it. It has a ring around it. Like there, there's just these incredible stories about some of these crazy objects out there.
There's a, there's a story. Eris is really fun. So, Eris, when we discovered it. We knew it was quite bright and really far away. It's about three times further away than, than Pluto is. And we could very quickly calculate that at the brightness that it had, unless it was the shiniest object we'd ever seen, it had to be bigger than Pluto.
So we were pretty excited about that one. Turns out. It's the shiniest objects we've ever seen. Of course. So, it's, but it was still bigger than Pluto. When we finally measured the size, we were like, great, it's still bigger than Pluto. And then Pluto got bigger. I think Pluto just decided that it still wanted to be the biggest one out there.
And so, it got bigger. So, when New Horizons flew by, Pluto turned out to be just a little bit bigger than people had thought it was before. I think it's true. I did go back and look at those data just to make sure they weren't trying to pull the wool over our eyes. But what's interesting is, Eris is about 25 percent more massive than Pluto.
On the inside of Eris, it's mostly rock, where the inside of Pluto is much more just ice, even though both of them are ice.
Dean Regas: Well, and then, of course, there is the oddest of them all, in my opinion, is Sedna. This is the object that goes so far away from the sun, and, you know, for people that loved Pluto because it was the oddball, can you help us embrace Sedna in the same way?
Mike Brown: So, Sedna is on an orbit that takes about 10, 000 years to go around the sun. It's on this incredibly elongated orbit. And what's actually the weird part about Sedna is it never comes closer to the sun than about Two and a half times the distance of Neptune, and it's there right about now it's about as close as it's going to get it's coming in a little bit closer still.
And the really interesting thing about it is that it tells us absolutely that something else has to have been either in the solar system right now. Or, in the past, to put Sedna on this very weird orbit, you can't form an object on an orbit like that with just the eight planets that we have now.
Something else must be or have been out there to make that happen.
Dean Regas: What do you think is the mover and shaker for Sedna that you're hoping?
Mike Brown: The only explanation we have been able to come up with at this point, and I think, I think it's the correct one, is that there has to be another giant planet in our solar system.
Much, much further out there pulling these guys into this orbit. Um, so much, much further means something like 20 times the distance of Neptune. So really far out there. And giant planet meaning something like probably six or seven times the mass of the Earth. A little bit smaller than Neptune, but a good bit bigger than
Dean Regas: The Earth. And this is what's nicknamed Planet 9 right now?
Mike Brown: This is Planet 9 because when you say Planet 9, people who, who still want Pluto to be a planet get really mad. So we thought it was a pretty funny thing to call it.
Dean Regas: See, there we go again. See what I'm telling you. So you feel like this is like a when we're going to find Planet 9, not a if we're going to find Planet 9?
Mike Brown: I really do. And the reason why is because we have repeatedly made new predictions on things that a planet like this should do, and they always work. And that I don't think is a coincidence. I think this is really true, and that we are going to find this planet, and there's a good chance we're going to find it sooner rather than later.
Dean Regas: Well, Mike, thanks so much for joining me today. This has been a lot of fun.
Mike Brown: Oh, this was great. Thank you for having me.
Dean Regas: The group who decided Pluto's fate, they're called the International Astronomical Union, or the IAU. And I'll be honest, the definition of a planet that they approved in 2006, well, it wasn't the best.
This is what it said. A planet is a celestial body that is in orbit around the Sun, has sufficient mass to assume hydrostatic equilibrium, a nearly round shape, And has cleared the neighborhood around its orbit. Yeah, that is not the best definition I have ever read in my life. A planet must orbit the sun, that's what they wrote.
What about things that orbit other stars? I know it's technical, but, you know. Alright, number two, a planet has to be round. I guess they don't want to, like, make it an arbitrary size, like a planet must be at least a thousand miles wide. And this kind of appeased the planetary scientists who were like, oh, it has to be big enough to be round and all that stuff.
Number three, though, planet has cleared its orbit. That, it's just more confusing because things pass by the Earth all the time. Asteroids, comets, temporary moons. Well, you know, at least we had that one temporary moon. Earth does clear its orbit after they pass by, but then another one comes along, so is that cleared or not cleared?
What the astronomers were trying to say was that a planet is a dominant force in its region. Anything that comes by a planet is moved by the planet, so asteroids are dominated by Jupiter, for instance. Pluto and Pluto's friends are dominated by Neptune. Yeah, I guess.
Mike Brown: The solar system does not consist of nine planets that are sort of more or less the same and then some other stuff.
The solar system is really a beautiful and complex place, and that complexity is reflected in the categories.
Dean Regas: Looking Up With Dean Regas is a production of Cincinnati Public Radio. Kevin Reynolds and I created the podcast in 2017. Ella Rowen and Marshall Verbsky produce and edit our show, and wrote strongly worded letters to Neil deGrasse Tyson, telling him Pluto is still a planet.
And I'm not talking about, like, when they were children. I'm talking, like, last week they wrote these. Get over it, you two, you're grownups. Jenell Walton is our vice president of content and Ronny Salerno is our digital platforms manager. Our theme song is Possible Light by Ziv Moran and our cover art is by Nicole Tiffany.
I'm Dean Regas. Keep looking up.
