Neil deGrasse Tyson – The Pluto Files

March 20, 2009

Neil deGrasse Tyson is an astrophysicist with the American Museum of Natural History, director of the world-famous Hayden Planetarium, a monthly columnist for Natural History, and an award-winning author. Tyson is also the host of NOVA ScienceNOW and a frequent guest on The Daily Show and Jon Stewart, The Colbert Report, and television documentaries on the universe. His latest book is The Pluto Files: The Rise and Fall of America’s Favorite Planet.

In this conversation with D.J. Grothe, Neil deGrasse Tyson recounts recent discoveries in astronomy, including methane on Mars and its possible implications, and questions regarding dark matter and dark energy. He explains how ignorance is seductive for the scientist. He details his involvement in the controversy regarding the status of Pluto, and the role of the Hayden Planetarium in the international debate over solar system nomenclature. He describes whether teaching the controversy over Pluto’s status is helpful in teaching astronomy, and how this compares to the “teaching the controversy” argument regarding evolution versus intelligent design creationism. And he shares his views about the best ways to teach the solar system to students, by comparing and contrasting objects in the solar system and how they relate to each other.

This is point of inquiry for Friday, March 20th, 2009. 

Welcome to Point of inquiry. I’m DJ Grothe the point of inquiries, the radio show and the podcast of the Center for Inquiry, a think tank advancing reason, science and secular values in public affairs and at the grassroots. My guest this week is Neil deGrasse Tyson. He’s an astrophysicist with the American Museum of Natural History and he serves as the Frederick P. Rose, director of the world famous Hayden Planetarium in New York City. He’s a monthly columnist for Natural History magazine and the award winning author of Origins and the bestselling Death by Black Hole. He’s also the host of the PBS mini series Nova Science Now and a frequent guest on The Daily Show with Jon Stewart, The Colbert Report and television documentaries about astronomy, science and the universe. Welcome back to a point of inquiry. Neil deGrasse Tyson. 

Thanks. Thanks. I think my third or fourth time on the show, I’d love being on camera. Thank you for having me. 

You know, before we talk about Pluto in science, just tell me what’s new in the life of America’s most famous astrophysicist. 

Well, it’s not what’s new in my life. It’s with new in the universe. And I guess tapped often by the media to comment on it. 

So, yeah, I see you on Kalbarri, Poor Daily Show, that sort of stuff all the time is somebody who seems out of control. 

But I can tell you that what excites the universe excites me and often can excite the public. 

Among them is, you know, just very. So you go down the list of recent discoveries, which include, for example, methane on Mars. Methane can be made without biology, but biology kind of does it for free. We have bacteria operating in the absence of oxygen. So it’s tantalizing hint that perhaps there is active biology going on on Mars and all the other telltale signs are there, the riverbeds dry. So they are leading us to think that maybe the water went subsurface and perhaps liquefied by some heat source and then sustaining an ecosystem. It’s all tantalizing Jim Underdown. 

And we still are dumb, stupid about dark matter and dark energy. Dark matter is 85 percent of all the gravity of the universe. 

And we don’t really even know what it is. 

We don’t even know when, in fact, we could call it Fred. Dark matter. It implies we know more than we actually do. Just those very words. We just call it anything. 

We don’t know what’s causing 85 percent of the gravity of the universe. And in dark energy, this mysterious pressure that is creating acceleration in the expansion of the universe, that remains mysterious as well. We can measure it. We just don’t know what’s causing it. And for many people, this level of profound ignorance would leave them in a combination of stupor and disappointment. But in fact, to a scientist, broad areas of ignorance are a seduction. It’s what draws you into the field because you might be the one who makes the discovery. So I’ll keep you off the street. 

Well, it’s good that you’re off the streets. You’re in the media. You’re. And you just said something that puzzles me. You know, scientists are the know it alls of society. But yet you’re saying not knowing is the thing that turns on scientists. 

You know, if you’re a good scientist and you’re on the frontier, the frontier is the boundary between what is known and unknown about the natural world. And that’s what it what excites the scientist. We’re a little bit we’re a little bit deluded, by the way newspaper articles are written about that frontier. For example, you read a headline and it’ll say, scientists now have to go back to the drawing board and give up your cherished theories about the. It makes you think that we’re sitting in our office with our legs up high and mighty masters of the universe when in fact, we’re puzzled every day. In fact, if you’re not puzzled, you’re not on the frontier. So to be puzzled, to go back to a drawing board is a natural state, not an unusual state. And that is the state at which you actually can be poised to make discoveries. 

Mm hmm. I invited you back on the show to talk about this controversy that you’ve been at the center of regarding the status of Pluto. We talked about it a bit on the show before, but now you literally wrote the book on it, The Pluto Files, The Rise and Fall of America’s Favorite Planet. I think the whole episode touches on what you were just kind of just now talking about. It tells us a lot about the culture of science, really how science works. 

Yeah. And it was not only about science, but about sort of the definitions of things and whether you get caught up in what something is defined to be versus what it is and versus its qualities or some backlash. 

That’s right. What I should’ve said, what you know, is what is how you categorize it. And are you categorizing it according to its properties or what it how it was formed or what it will become. 

And so there’s a lot of sort of philosophy of scientific nomenclature that was involved in this entire episode. 

Give her listeners the background of the controversy, how it all started for you at the Hayden Planetarium, what you were doing, some remodeling at the planetarium redesign of the space remodeling understates what we actually did. 

It was a. Rebuilding of the entire facility, which would include a re remodeled Hayden Planetarium, but a completely rebuilt museum of the universe. So there was an occasion to rethink how the universe and its themes and objects would be presented to the public. And we took that occasion to notice that there in the 1990s, because we opened to the public in 2000, sold homework, was done in the 1990s, that there were new objects being discovered in the outer solar system. That kind of resembled Pluto in many ways. They were small, like Pluto. 

They were mostly icy by volume, like Pluto. They had kind of weird orbits like Pluto. And we realized we said, wait a minute. Maybe Pluto is not simply the ninth planet. Maybe Pluto was the first object discovered in this new swath of real estate in the outer solar system, which came to be known as the capable jarraud. Kuyper was a astronomer at MIT Century, a theorist who predicted that beyond the orbit of the outermost large planet, you’d have this reservoir of sort of leftover stuff that might have been gravitationally vacuumed up if there were a large planet to do so. But beyond the outermost large planet, there isn’t. So it would still be out there. And he said, go look for it. He made that prediction in the 1950s. It took 40 years before telescopes got powerful enough to make a good survey of that outer region. And sure enough, they started getting discovered. So all we did was group Pluto with its icy brethren in the outer solar system. That’s what we did. We didn’t recount the planets. We didn’t declare they’re only eight planets in the solar system. 

In fact, you don’t even really use the term planets in your work. 

Yeah, the word planet is used kind of peripherally. It’s not the organizing principle of how we present the solar system. We grew up the rocky, the rocky planets, Mercury, Venus, Earth and Mars as having more in common with each other than any one of them has with anything else in the solar system. Here’s the asteroid belt familiar to everyone who watches science fiction, story movies, cracky chunks of rock that are cluttered between Mars and Jupiter. Have the gas giants Jupiter, Saturn, Uranus and Neptune. They’re big. They’re bulbous. They’re low density. They have rings. They extensive moon systems. But you have the icy bodies in the outer solar system to those among them. And so we put it that way. And we judge that Pluto is probably happier there as a cosmic object because it was with other things that behaved much as it does. 

So when you did this reorganization, you actually got flack from what you call in the book Pluto files. Was most of that flat tongue in cheek or were people really up in arms? 

That’s an excellent question. We went for a year without much commentary because, like I said, there was no neon sign declaring we show only eight planets. What happened a year after we opened The New York Times broke the story. And they must’ve thought that the story of the decade when they published on page one, Pluto, not a planet only in New York. And that’s what inflamed the public. That headline Jim Underdown. 

So you said inflamed. Some people were so upset. It’s like you’re talking stem cell research or revolution of stuff. 

Yeah, it it apparently flipped a nerve within people of all ages. I got hate mail from third graders who who had just learned about their planets and just duly memorize their sequence from the sun. And here we were removing it from this sort of memorization scheme that they worked so hard to to master that letters from colleagues, many of them who were professionals, who study planets and Pluto, who were angered that they presumed we had taken Norman Claytor into our own hands and decided to redefine a word that had been used for so long. So everybody chose Upside’s and there was a subcommunities among them, including those who study the capability who were first to declare that we did it right and we did the right thing. And something really needs to happen to Pluto. 

So there were these two sides, some people up in arms, other people agreeing with you. But in the wider community at large, kind of, you know, the public, most people thought you were on the wrong side of the fence. 

Exactly. And the public especially. 

Yes, New Mexico and California, did their state legislatures actually pass bills or resolutions defending Pluto’s status as a planet? 

This saga dragged on for six or seven years. And towards the end of it was when the international community officially voted on the definition of a planet. And in so doing, Pluto was excluded from the pantheon of planets at that point. Officially, we didn’t vote on the definition of planet in our exhibit. All we did was present the contents in a new way that in our judgment was educational and scientific highroad. 

But you weren’t renaming? 

No. We weren’t we were stereotyped as having done so, but we actually didn’t. But it was not until the official vote was taken because over those years. Slowly but surely, more and more people came to understand what we did and why. So the trend line was in our favor. And six years later, the International Astronomical Union officially proposed a definition, voted on it and declared Pluto is no longer an official planet but a dwarf planet. And that’s when you had these official responses by New Mexico that put out legislation declaring that within the borders of New Mexico, Pluto is a planet, no matter what it mean spirited astronomers thing. Why New Mexico? Because that’s where the discover of Pluto spent his latest year’s high tumble to discover Pluto taught at the local universities of New Mexico and spent out his later years there. His wife is still a resident of New Mexico. So that was their attempt to do right by Clyde Tombaugh. Meanwhile, California gets in the air. They proposed legislation basically rebuking the international astronomical community. Why out of concern that a lot of this was tongue in cheek, but it still nonetheless. California. Tax dollars at work. Who gives her legislators putting together legislation declaring that the two demote Pluto is to disrespect one of California’s most famous cartoon characters. And they’re worried about what the financial consequences of that would be by reduced visitorship to Disneyland. 

OK, so that’s funny. That’s a little silly. But isn’t that one of the reasons why America was so wrapped up in this Pluto issue? You know that the category of Pluto being a planet or not was an American controversy mostly. 

My first thought was, you know, why is everyone in America so concerned? Because Europeans really didn’t care much at all. Find a European and ask them and they’re going to look at you like what’s wrong with you? To have this much emotional investment in a planet. And I thought maybe it’s because an American discovered Pluto. So then I polled these people who felt so strongly, these Americans, that only 10 percent of them even knew that. So I had to look a little deeper. And that’s when I realized, of course, that Pluto. The dog. Mickey’s dog. The Disneyland character. The Disneyland character. Pluto, the dog was first sketched the same year that Pluto, the cosmic object, was discovered. So they have the same tenure in the hearts and minds of Americans. And if you’re a pretty normal kid, you would have learned about Pluto, the dog, right. About the same time you’re taught the planets in the solar system and you don’t know anything about Mercury as a Roman messenger. God, it’s just a word to you at that point. You don’t learn about yet. Not in first or second grade yet. So you hear the enumeration of planets has given by your school teacher, Mercury, Venus, Earth, Mars. It’ll mean anything to you. You get to Pluto. And they’re your ears perk up. And you remember the character. And I am certain that that’s where this genetic link gets established in the hearts and minds of all Americans. 

I’d like to let our listeners know that you can get a copy of the Pluto files, The Rise and Fall of America’s Favorite Planet through our Web site point of inquiry dot org. Neil, do you think that teaching the controversy over whether or not Pluto is a planet or just part of the Kuiper Belt, does it help students learn astronomy? In other words, is is this controversy something that should be covered in the schools? You mentioned that you got a lot of letters from schoolchildren about this, right? 

Yeah, some of which are even in the book. Some of the more colorful, really, really humorous. 

I just love this book. You know, it’s kind of a miniature coffee table book in a way. 

Thanks for recognizing that about it. Heavily illustrated. And that was part of the fun of putting together and making a story arc out of it from beginning controversy to the science of Pluto right on up through and tracking of the human emotions around what we call the thing. And one of my favorite letters was from a girl who who chides me for getting rid of her favorite planet and favorite planet of her classmates. And in the end, it says right back soon, but not in cursive. I can’t recursion. So while this was going on, I got intermittent emails and snail mail correspondence from school teachers who said, you know, we happen to like Pluto as a planet. But thank you for making this a subject that we can debate in class. 

And there was a lot of correspondence like this. And I take a different view. I would claim that the debate should not be about whether Pluto was a planet or not as an excuse to then get real science into the classroom. The debate should be about how you teach the solar system in the first place. I submit that our collective attachment to Pluto has the ninth planet is the consequence of how the solar system was taught. You go in. You don’t learn about comets lashing into planetary surfaces. You don’t learn about the volcanoes in the solar system, the ring systems, the fascinating. Is the fact that I owe one of Jupiter’s moons might have a liquid ocean that’s been kept warm by the gravity of Jupiter for billions of years. You don’t learn about any of that. The teacher sits you down and says class. We’re not going to learn about the solar system. Memorize these nine names in order. And by the way, here’s a mnemonic to help you. 

My very educated mother just served us nine pizzas Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus and Neptune, Pluto. If that’s how you’ve learned, then the sequence becomes ossified in your head. You think that that’s science. You think that that learning science teacher even creates a test and ask you questions like what is the name of the fifth planet from the sun? That’s my science. Had it been taught differently by comparing and contrasting objects within the solar system. And looking at their behavior and how they relate to each other, then Planet Count becomes in an insignificant little factoid that you tag on at the end of the park. 

Oh, by the way, Pluto, we’re now thinking of it as an icy body rather than as a planet. Oh. Joining the rest of the icy bodies in the outer solar system. That’s cool. Let’s see how it compares. That’s how that should have unfolded. You don’t debate the definition of a planet just so you can change the number of planets you going to teach in the classroom. 

Nonetheless, wasn’t the debate about the definition of the planet, the the teaching, the controversy over over this and maybe your role in it? You got these letters. Wasn’t it an entry way into the discussion about the solar system? 

It was indeed an issue. Because no one had the occasion to speak so extensively about Pluto until this controversy. I agree. What I do in the last chapter of the Pluto files is offer a recommendation to school teachers, parents and kids about how to think about the solar system going forward. I didn’t want it to be a debate. Are there eight planets or are there nine? I’m uncomfortable with that because that misses the richness, the rich tapestry of scientific discovery that has unfolded over these recent decades by virtue of NASA’s space probes and rovers and orbiters and flybys. It was a day when the word planet couldn’t do much more than pointing out the lights in the sky that moved against the background stars. I guess with the word planet means in Greek, it means wonder if that’s all you knew about these objects. Fine. Count them. Go ahead. Or there are there nine and not much else you’re talking about because the space programs haven’t been invented yet. But just look at the sheer breadth and depth of knowledge we have glean about the richness of the solar system. And we have school teachers worrying about how many planets there are. I just think it’s misguided investment of pedagogical energy. 

So the controversy over Pluto, not the best way to teach the solar system. I bet you think the same thing about the teach the controversy argument over, say, evolution. We’re told that we should teach the controversy over evolution in the schools as a way to kind of be fair about the issue and also as an entry way into exploring biology and in human origins. 

These cases are different in the following way. There were actually scientists fighting with each other about how many planets there were in the solar system. 

Even so, that doesn’t make it the most noble way to approach the subject. 

But there was a real scientific controversy. 

It was a real scientific debate over the lexicon, over the Norman culture. There was no debate about Pluto’s properties or the science of Pluto. So it was really about just simply what you call things, not the ideas surrounding the science of the solar system. Whereas in the teach the controversy mantra of evolution, if you want a teacher controversy. Let it be an actual scientific controversy. Go ahead. But if the controversy is people who who have a religious agenda versus those who have a scientific agenda. 

That’s not a scientific controversy. That’s a cultural controversy. That’s a sociological controversy. Teach it in sociology class. Go ahead. I don’t have a problem with that. If these are real issues going on in courts, and I think that’s kind of a fact about the world we now live in in 21st century America. You can’t sweep that under the rug. 

But it doesn’t belong in a biology class. 

Exactly, because it’s not biology. It’s something else. 

Jim Underdown, if you’re going to teach the controversy about evolution, you teach the controversy over punctuated equilibrium or, you know, mechanisms of evolution. 

Exactly. You pore over the journals of biology and see what interesting biological controversy there are, if you like, teaching controversial science. Go ahead. Every published peer reviewed article in a journal is in principle about some controversial subject because it’s on the frontier of our ignorance, on the frontier of our knowledge. That’s the same line in the sand. And so there’s there’s no shortage of science controversy if we want to put it in there. But you don’t have to ask religious communities for what they object to and then bring that to the science. And say, here’s the controversy. That’s a complete misrepresentation of the scientific process. Whereas with Pluto, like I said, you could have debated how many planets there are. I just don’t think that’s the most interesting thing to learn about the solar system. 

Gotcha. So this whole issue of Pluto changing from a planet to whatever it is now, dwarf planet. 

Dwarf planet. 

You were just suggesting that that says something about science, you know, being on the frontiers of science, actually, that is more about nomine culture. But, you know, you were talking about controversies within science. But isn’t science supposed to be the truth? You’re saying it’s always changing. Scientists actually seem to like that fact. 

Well, when there’s consensus, you chalk it up as the truth and go on to the next problem when there’s not consensus. No one is declaring a truth, just declaring what they think might be true when better data comes available. That’s really what’s going on on the frontier. And newspaper articles about that frontier rarely convey the published uncertainties in the results of the scientists present because it quantifies the journalistic process right in the media. 

We often get thus, says science. 

So here’s how I would use Pluto to highlight science being about the truth. What you say here is, you know something? We were wrong all along. Pluto is not the ninth planet, although. It was giving a sign that it wasn’t all along its orbit crosses the orbit of Neptune. No other planet does that. It’s smaller than seven moons in the solar system. It’s got some really oddball properties shared by no other planet. It was calling to us all along. We’ve realized that, no, Pluto is not the ninth and most diminutive of a class of eight other objects. It’s the first object discovered in this new swath of real estate we call the Kuiper Belt. And for me, as a scientist, that’s a much more fascinating place to be because the body of knowledge has grown. Yes, we lost one planet, but we gain an entire new place. 

You like it? That science was wrong there. 

In that case, science was wrong because we didn’t realize how much more complex the solar system was. I don’t mind being wrong. It’s natural to think that what you just discovered is kind of all there is. Right. And so you make up rules and regulations and normally claim it to account for that. Then you’d study some more. You find out, hey, this is just a small part of something bigger. But you’re stuck with your whole vocabulary. So now you have to fix your vocabulary and broaden your sense of how things are and what they mean to you and what your relationship is to them. And that’s what the Kuiper Belt has become to the solar system. And I think the solar system is a richer place for it. I once gave a talk and someone said, would you carry on this way in front of Clyde Tombaugh if he was still alive? Clyde Tombaugh, the Discover Pluto. And I said, well, he’s dead. That’s right. He said, well, you know, his wife, his widow is still alive. What would you say to her? Because you’re you’re besmirching his legacy as the discover of a planet. I would say, Mrs. Tombo, your husband. No, he did not discover the ninth planet. He discovered something much greater than that. He discovered a new class of object in the solar system. And that is something to be proud of. Far greater than just simply the. And Littlest, among eight others that have already been well known and researched. And so I don’t think that’s a stretch to say that that’s not spinning some kind of an account just so we don’t hurt her feelings. I think it is a genuine and honest statement about the progress of science, broadening our understanding of the world in which we live. 

Mm hmm. Thanks a lot for coming back on the show. I enjoyed the discussion, Neal. Thanks for having me. 

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Point of is produced by Thomas Donnelly and recorded from St. Louis, Missouri. Executive producer is Paul Kurtz. Point of Inquiry’s music is composed for us by Emmy Award winning Michael Quailed. Contributors to today’s show included Sarah Jordan and Debbie Goddard. I’m your host DJ Grothe. 

DJ Grothe

D.J. Grothe is on the Board of Directors for the Institute for Science and Human Values, and is a speaker on various topics that touch on the intersection of education, science and belief. He was once the president of the James Randi Educational Foundation and was former Director of Outreach Programs for the Center for Inquiry and associate editor of Free Inquiry magazine. He previously hosted the weekly radio show and podcast Point of Inquiry, exploring the implications of the scientific outlook with leading thinkers.