Astrophysicist Tyson On 'Pluto Files' The director of the American Museum of Natural History's Hayden Planetarium and author of The Pluto Files, Neil deGrasse Tyson, talks about the future of NASA, Pluto's demotion to dwarf-planet status, and the difference between Darwin and Einstein.
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Astrophysicist Tyson On 'Pluto Files'

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Astrophysicist Tyson On 'Pluto Files'

Astrophysicist Tyson On 'Pluto Files'

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For the rest of the hour - Pluto, the universe, everything in between. You know, from the time we were kids, we were taught there were nine planets in our solar system - Mercury, Venus, Mars, Earth, Jupiter, Saturn, Uranus, Neptune and of course, Pluto. There - the very edge of the solar system - right out there, Pluto was - is all by itself. Well, for over a decade now, the status of Pluto has been debated. It's not anymore classified as a planet. It's really just a chuck of rock and ice in something called the Kuiper Belt, the argument goes. And in 2006, the International Astronomical Union voted Pluto out of planethood, demoted it to a dwarf planet.

But wait! Of course it's a planet, came the cry from thousands of saddened Pluto's demoters, who would said, we're not sitting - we're not standing for this. A planet is whatever we say it is, and if we say it's a planet, then Pluto is a planet, they cried back. So, the debate has not been finalized yet. And here to talk about that debate and I think the person who's probably started the whole thing - right, Neil?

(Soundbite of laughter)

FLATOW: It's Neil deGrasse Tyson, astrophysicist and Fred P. Rose director of Hayden Planetarium at the American Museum of Natural History. He has a new book out called "The Pluto Files: The Rise and Fall of America's Favorite Planet." And it's a great little book. I recommend it to you. And in his spare time, he hosts NOVA scienceNOW, has all kinds of lectures and authoring all kind of other kinds of books - finger in everything. Welcome back to Science Friday.

Dr. NEIL DEGRASSE TYSON (Author, "The Pluto Files: The Rise and Fall of America's Favorite Panet"; Director, Hayden Planetarium, American Museum of Natural History): Thanks for having me back. It's been a while.

FLATOW: It's been a while. Why is Pluto America's favorite planet?

Dr. TYSON: I thought long and hard about this, and I concluded, in the end, that it had to be the dog. I blame the dog.

FLATOW: Woof woof.

Dr. TYSON: The dog.

FLATOW: The Disney dog.

Dr. TYSON: Mickey's dog, Pluto.

FLATOW: Why would we care about it?

Dr. TYSON: Well, in America - think about it - when do you first learn about the planets? And typically they're taught as an enumeration of objects in sequence from the sun. You learn this in first, second, at most, third grade. And that's the age when you're very susceptible to cartoon characters. And if you're in America, you probably haven't learned Roman mythology yet, so the name Mercury doesn't mean messenger God of the Romans to you, it's just a name. So, Mercury, Venus, Earth, Mars, Jupiter, Saturn - you get on out to the end, and then the teacher announces, Pluto.

(Soundbite of laughter)

Dr. TYSON: And at that point, you're hooked. You're hooked on the object, because you know there's a dog named after it. And so - and not only this, Pluto, the cosmic object, was discovered in 1930 by Clyde Tombaugh, an American, and that was the same year that Disney first sketched Pluto, the dog.

FLATOW: Is that right?

Dr. TYSON: It's the same year. And so, they have the same tenure in the hearts and minds of Americans. So, this link is inextricable. I would even dare - dare I call it genetic?


Dr. TYSON: We have a genetic connection to Pluto - its status, its meaning, its presence in the elementary school curriculum.

FLATOW: And if this - so, you're saying, if it had not been a dog, if it had been called something else, we might not have had that connection?

Dr. TYSON: I'm convinced of that, that's correct. It would have - not have - you would still have people debating it.

FLATOW: Right.

Dr. TYSON: But it wouldn't have the emotional fervor, it wouldn't have the breadth and depth to which the public reacted that the current controversy brought onto the table.

FLATOW: So, until this ruling was made, you were basically the forefront of…

Dr. TYSON: Yeah, back in the year 2000, we had a completely rebuilt Hayden Planetarium, taking on the larger name of the Rose Center for Earth and Space. And we had occasion to have to think deeply about how we're going to present the universe to the public. And we looked around, looked in the outer solar system, saw that there were new objects being discovered out there - icy bodies that kind of resembled Pluto in composition and in orbit and in size. And we thought to ourselves, maybe the right way to teach the solar system - because we also wear educator hats. We're not only scientists, we're educators there - is to organize the contents of the solar system by like properties. So, we took Pluto, grouped it with these other icy bodies, presented it that way - and grouped the gas giants together. They all have rings, they're all big and bulbous. And so, that's how we presented it.

FLATOW: All right, we're going to get back with Neil Tyson, author of "The Pluto Files," - back with him after this short break. Stay with us. If you have questions about Pluto, the planets, the cosmos - anything you'd like to talk about - space, space exploration, NASA, got a while to talk with Neil. So, stay with us. We'll be right back after this break.

(Soundbite of Talk of the Nation theme)

FLATOW: I'm Ira Flatow. This is Science Friday from NPR News.

(Soundbite of music)

FLATOW: You're listening to Talk of the Nation, Science Friday. I'm Ira Flatow, here with Neil deGrasse Tyson, who's author of the new book "The Pluto Files," talking about his trials and tribulations. A lot of anecdotes in the book - it's quite interesting reading, and it's a lot of fun. Neil, did you decide there was at some point you had to write all this experience down, because you have all kinds of wonderful letters from kids in there, you have the debate in there, you have…

Dr. TYSON: Well, the letters from kids didn't come until the New York Times made our exhibit decision a page-one story - page-one story. After a reporter from the New York Times overheard two visitors at the museum asking themselves where is Pluto, upon viewing the gas giants organized together and the rocky Mercury, Venus, Earth and Mars grouped together. And they didn't see Pluto. And they - the New York Times reporter said, well, I think I've got a story here, phoned it back into headquarters. They sent up a science reporter and a photographer, and out came a page-one story that said, Pluto not a planet? Only in New York.

(Soundbite of laughter)

Dr. TYSON: And at that point, that's when the hate mail started coming in from elementary school children. And I had this burgeoning file - angry, pissed off, third graders. Dear Dr. Tyson, why didn't you - where's Pluto? Put it back in. It's my favorite planet. Why, you - that's discrimination against little planets. Why are you doing this? And here's a picture of it. And it's scrawled in crayon. And so, (Laughing) I had this file. And by the way, children were not the only ones to write to me, including colleagues who were - people were choosing sides in all population demographics across the country.

FLATOW: Mm hmm. And so then, how was it finally resolved, this issue of whether Pluto was a planet or not?

Dr. TYSON: Well, we were the first public institution to bring this to light. And by the way, we didn't just pull it out of the ether. There'd already been sort of a percolating debate about Pluto that had been going on for a couple of decades, but it was only in, you know, behind closed doors and the coffee lounges of science departments. So, we were the first to sort of shake it out of that environment and put it into the public focus. It took 6 years, but the International Astronomical Union - it's not a labor union in that sense; it's a society of international astronomers - got together, created a planet definition committee, made suggestions about it, and then a vote was taken. And in the end, there was a new definition for planet, which, by the way, had not been officially defined since ancient Greece.

FLATOW: No one had a definition?

Dr. TYSON: We did not have a definition - not since the original, where - if you wandered against the background stars, you were a planetes. You were planetes, which is Greek for wanderer. And there were seven - Mercury, Venus, Mars, Jupiter, Saturn, the sun and the moon. Those were the seven planets that everyone could agree wandered against the background sky.

After Copernicus put the sun in the middle and the moon going around the Earth, the planet count changed from seven down to five and up to six, because you lost the moon and the sun, you gained the Earth. And at that point, a planet was just kind of - just whatever seemed to go around the sun, and nobody formally thought more deeply about it, until the asteroids were discovered.

That was interesting. The first asteroids were called planets. There's like several years there in the early 1800s where the planet count was rising through the upper teens, until people - clearer heads prevailed and said, hey, wait a minute, folks. What we just discovered are not a bunch of planets. We discovered a new kind of object in the solar system, which today, we identify as the asteroids forming the asteroid belt.

So, I submit to you that Pluto and its discovery is a mirror of what happened with the discovery of the asteroids. You discover this object Pluto. It was always kind of weird. Its orbit crosses the orbit of Neptune. It's tipped out of the plane of the solar system. It's odd, but you can't make a class of one. So, we just kind of grandfathered it in and say, OK, Pluto, you're one of us. Then, in the 1990s, icy bodies started getting discovered in the outer solar system - say, hey, we've been down this road before. Pluto is not the ninth planet; it is the first object of a new swath of real estate that we now understand to exist in the outer solar system. And that's what we did.

FLATOW: So, there are like icy body - Pluto's really sort of an icy body that comes from the solar system…

Dr. TYSON: Yeah…

FLATOW: Better like a comet than a planet?

Dr. TYSON: Yeah, I'm hesitant to call it a comet, because comet still has a need of some refinement of its definition itself. But it is true that if you brought Pluto to where Earth is right now, heat from the sun would evaporate the ice, and it would grow a tail. Pluto at Earth's distance from the sun would have a tail, a really big tail at that. So, to me, that's a comet, but I don't want to open up a whole other can of worms here.

(Soundbite of laughter)

Dr. TYSON: Let me just say that Pluto…

FLATOW: (Laughing) Well, we'll get you in trouble before the day...

(Soundbite of laughter)

Dr. TYSON: Yeah, I'm already in trouble, so just - so anyhow - so the IAU voted. And so, the new criterion for planets - so they voted because they understood something needed to be done, something we had known for many years - for five - for six or seven years. So, the definition of a planet - it's now official - is first, are you round? Put a check in Pluto's box.

FLATOW: A lot of things are round.

Dr. TYSON: (Laughing) A lot of things are round. Put a check in the box.


Dr. TYSON: All right. Second, are you the principal object in orbit around the sun? This is the moon discrimination clause, (Laughing) as far as I see, because you could be round and - but if you orbit something that's bigger, you…

FLATOW: Yeah, fits the moon, yeah.

Dr. TYSON: OK. Then the moon would not fit this category. So, Pluto has a relatively big moon, but not bigger than it, of course. So, Pluto satisfies that criterion. Put a check in that box. Third one, have you cleared your orbit of orbital debris? Do you dominate in your orbital zone? Pluto does not. Pluto is in a community of countless thousands of other icy bodies in the outer solar system. And so, Pluto fails that third criterion. It's now officially a dwarf planet.

And some people took offense at this - dwarf? They've demoted it. And - but others said, well, it's just a kind of planet, in the same way if you drive a compact car, you're not going around town saying, I wonder if I'm actually in a real car. You're not having these thoughts. You're not having this existential angst over whether or you're in a real car. You're driving a compact car. So, some wanted people to feel that dwarf planet just is a kind of planet. We have dwarf galaxies, those galaxies don't complain.

FLATOW: Right. Right.

(Soundbite of laughter)

Dr. TYSON: So - and to this was added another definition - if you're a round object beyond Neptune, you're icy - because that's - you're far enough away to retain your ice and - you're a plutoid.

FLATOW: Plutoid?

Dr. TYSON: A plutoid. And the biggest asteroid, which happens to be round - the only round asteroid - got elevated to dwarf planet status because it's round…


Dr. TYSON: It's the predominant object. It doesn't have a moon, and it hasn't cleared its orbit, because the asteroid belt is littered with hundreds of thousands of other craggy chunks of rock. So, we now have at least Ceres, the asteroid that's round, Pluto, as dwarf planet, and several others in the outer solar system.

FLATOW: 1-800-989-8255. Let's go to Brian in Delaware. Hi, Brian.

BRIAN (Caller): Hey, how you doing? Great conversation.

FLATOW: Thank you.

Dr. TYSON: All right, thanks.

BRIAN: Hi. I'm an eighth grade teacher. We teach planetary science as one of the four units in the curriculum. And we do have a unit addressing planets - I'm sorry - addressing Pluto's demotion. One of the things that I like about it is that it - oftentimes, kids sort of get stuck in that science is the way it is, and it doesn't change. And it's a departure point - the way we teach it - to, you know, as we learn more, science evolves and adapts with that knowledge. So, I think it's a great thing that you've done this.

Dr. TYSON: Well, thank you. And I'd like to add - by the way, I never lose sight and respect of the fact that you, as a teacher, are in the trenches making this stuff work. You know, I can show up on TV, you know, till the end of the day, but in the end, you're the one who's, like, enacting - you're there in the trenches. So first, I have my deepest respect for that.

BRIAN: Thank you. That's nice.

Dr. TYSON: Particularly at a time when students are hormonally driven…

(Soundbite of laughter)

Dr. TYSON: (Laughing) If you're in eighth grade there.

(Soundbite of laughter)

Dr. TYSON: We ought to have, like, a hormone blocker, so that you can actually, you know…

(Soundbite of laughter)

Dr. TYSON: You've got the hardest job in the educational pipeline. But to your point, I save - you know, I feel - I have strong feelings - pedagogical feelings - about this, which I contain and reserve for the last chapter of the book. The rest of the book is really a celebration of people's reactions, not only school kids, but teachers and humorists. But in the last chapter, what I appeal to is that people should no longer feel the obligation to count planets. No matter what the definition is, the number of planets is not a scientifically interesting fact. And what I want to urge people to do is think about the solar system as groups of objects of like properties.

BRIAN: Right.

Dr. TYSON: So, as I was saying, the gas giants - they're all big and round and low density, and they have rings with huge moon systems, and they have storms - talk about storms in the solar system.

BRIAN: Right.

Dr. TYSON: If you did that, you'd talk about the big gas giants, as well as the Earth, for example. So, you take cuts through the data in ways that highlight what is the subject matter of interest at the time. And if that's your approach, then it doesn't matter what the definition of a planet is, you're going to be talking about all the rest of the enriched contents that we've come to learn about the solar system from our probes, from orbiters, from landers, from rovers and the like. So, one last point I'll make is that I think people were upset that if Pluto got demoted, that science would somehow retract.

BRIAN: Yeah.

Dr. TYSON: I think people understand that science can expand your knowledge, but if you started with nine and now they are eight? That's an affront!

(Soundbite of laughter)

Dr. TYSON: So - plus it got memorized to be nine, so there's an ossification that went on in your brain. So, the way I'd like to think of it is, you think of Pluto not as the ninth planet but as the first object discovered of an entire new class of object in the solar system. And so, in that regard, the science did in fact broaden our horizons.

FLATOW: All right.

BRIAN: I think that approach is great. I just want to thank you. I look forward to reading your book.

Dr. TYSON: All right. Thanks.

FLATOW: And the book is called "The Pluto Files" by Neil deGrasse Tyson. It's really a great, great fun read. We have a comment here from - a Twitter that came in that says - from a company, it says, Dr. Tyson acted well recently on "Stargate Atlantis."

Dr. TYSON: Oh, you didn't see "Stargate Atlantis," did you?

(Soundbite of laughter)

FLATOW: (Laughing) I'm reading it right of the...

Dr. TYSON: I had a - it was a cameo. Here's the upsetting part about that - I did a cameo playing myself on "Stargate Atlantis."

FLATOW: Right.

Dr. TYSON: And I thought I did a pretty good job. I got home - it was like, I sucked.

(Soundbite of laughter)

Dr. TYSON: I'm not an actor.

FLATOW: Keep your day job, right?

(Soundbite of laughter)

Dr. TYSON: I definitely - quickly ran home, said, I'm keeping my day job. The sad part is, how could you suck at playing yourself? You know, that was the worst part.

(Soundbite of laughter)

Dr. TYSON: I was invited to be in the whole episode. I even constrained it to just the cameo. But thanks for noticing that.

FLATOW: Well, they are people who watch you. Let's go to the phones - Jim in Birmingham, Alabama. Hi, Jim.

JIM (Caller): Dr. Tyson, this is a thrill. I want to thank you for helping fill that massive void left by Dr. Sagan in the realm of public science education - love watching you on TV.

Dr. TYSON: Well, thank you. Thank you very much.

JIM: I speak to students. I'm not a teacher, but I speak to students and civic groups about space exploration, particularly the Apollo era. I'm a good friend of Andy Jakins(ph). And I hear a lot of feedback from students that reflects bad science and astronomy - bad astronomy that I read myself on Internet pages and read in Internet discussion groups - for example, a lot of mythology about space radiation.

Do you have a kind way of telling people that what they believe after reading this material is wrong and that they really need to work on sharpening up their critical thinking skills? I would appreciate some advice on dealing with that. I know you've run into people who may bring up the Apollo hoax or UFO mythology or something like that. What do you say to those people?

Dr. TYSON: OK, that's an excellent question, and you know, do we have three hours, Ira, to do this?

FLATOW: Well, we'll extend the program.

(Soundbite of laughter)

FLATOW: Let me just remind everyone, so that we can. This is Science Friday from NPR News. I'm Ira Flatow with Neil deGrasse Tyson, author of "The Pluto Files." Go ahead.


FLATOW: I'll give you certain amount of time.

Dr. TYSON: OK. Sure. I don't have a silver bullet. So, some of this has to happen sort of a la carte. For example, when alien people want to sort of show you their videos, I say, I'm not interested in videos. You want me to believe that you had an alien encounter? Drag the alien carcass into my lab. Then we'll have sort of a conversation to have about what you just encountered. Or bring me something of alien manufacture. Next time you're abducted and they're doing the sex experiments, as they always do on you when you're abducted, tell them to look the other way. And then snatch, like, the ashtray off the shelf. Bring that to the lab, because of it's of alien manufacture, we will know it instantly. And until that happens, I'm just not interested in fuzzy footage of what people don't recognize in the sky.

And so, the challenge then gets put back to them to produce the evidence befitting the depth of the claim. In terms of other people with belief systems - as you know, there's this rampant notion that the world is going to end in the year 2012. That's a kind of fun one, because one of the claims is that the center of the galaxy, the sun and the Earth will come into perfect alignment on December 21st in 2012. And that perfect alignment will alter Earth's axis and so, it's true. Those three - the center of the Earth, the sun and Earth - sorry - the center of the galaxy, the sun and the Earth - will come into perfect alignment.

And what they don't tell you is that that alignment happens every year on December 21st. So, without even performing a calculation, you can show the absurdity of that claim. And so, what I've found to be much more useful is, rather than saying, we're scientists and we know or do the math, is to explore other sort of comparative situations that are obvious to them - where the truth is obvious - and make that the analogy to the fictional ideas that they have. And then they end up shedding what they've been carrying with them. But apart from that, I'm actually working on a whole other book on how to raise a scientifically literate child. And you want to get them thinking the right way in the first place, rather than having to undo it later.

FLATOW: All right. We're talking with Neil Tyson, author of "The Pluto Files," on Science Friday from NPR News. In fact, you sort of experiment a little with your kids on these…

Dr. TYSON: Well, I don't put electrodes in their head or anything…

(Soundbite of laughter)

Dr. TYSON: But I immerse them in environments that will stimulate their curiosity about the natural world.

FLATOW: And that's an important time in their life to get them.

Dr. TYSON: Yeah, because kids are born scientists. Kids are born think - experimenting. When was the last time you were with a kid and they didn't want to look underneath the rock or didn't want to sort of experiment with your dishes or your pots and pans or the knobs on your stereo system? You know, these are things kids love to do. And what's the first thing you tell them to do? You say, stop it. You might break it. You might make it dirty. You're halting their experiments with the natural world, especially if a lot of their natural world is coming to them through your household, household good items.

FLATOW: Right. And so, you say that it's not the kids who are the - have problems with science, the adults - reaching the adults is.

Dr. TYSON: I have adults who tell me, how do I get my kids interested in science? How do we get kids interested and science literate? I say, excuse me, my biggest problem today is getting adults to be science literate, because kids don't say - kids up to age 12 you will never hear say, oh, what's my horoscope? Oh, will the world actually end in 2012? Oh, is the - they do not have the pseudoscientific burdens that adults carry, because they're just curious about the natural world. It's later in adulthood, when life gets more complicated and - with your social life, your love life, your financial life - that people start sort of reading their horoscopes and thinking about the end of the world. And they start taking on the whole other sense of their relationship to the laws of nature. And of course, adults vote, they vote for lawmakers. So, my first priority is actually getting adults to be scientifically literate, and then, that'll help nurture the kids that they have.

FLATOW: Because I think that, you know, kids are - as you say, they're scientifically literate, but they don't find any support for it once they get into school.

Dr. TYSON: Yeah, unfortunately, because they have the textbook, they have the curriculum. Part of what I'm doing with my kids is not doing, here's your science experiment for the week. Get three parts of this and two parts that. No, no, no, no, no. That's not the expression of curiosity.

So, what I do is you buy a satchel of magnets and throw it into the room, and they start playing on their own. And you just immerse them. I have an ultraviolet light that I turn on every now and then. You experiment to see what looks different under an ultraviolet light, from butterfly wings to different rocks, to the - if you're wearing a specially bright white shirt that'll glow. So, they're just little things you just throw into the environment and that'll - and you want them to keep that curiosity all the way into adulthood.

FLATOW: All right, we're going to take a break. We're talking with Neil Tyson - Neil deGrasse Tyson, author of "The Pluto Files," on Science Friday. Stay with us. We'll come back and take a lot more of your calls. Our number, 1-800-989-8255. We're also tweeting on Twitter. Our Twitter is @scifri and a whole bunch of folks still in Second Life. You can join Second Life, you can join our twitters and talk with folks of like-minded ilk, whatever that means. Stay with us. We'll be right back.

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FLATOW: I'm Ira Flatow. This is Science Friday from NPR News.

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FLATOW: You're listening to Science Friday on NPR News. I'm Ira Flatow with Neil deGrasse Tyson, author of the "The Pluto Files." Also, you can catch him on NOVA scienceNOW and various - he's going to be on a book tour - he's also on Stephen Colbert and also on Jon Stewart. How are those experiences?

Dr. TYSON: They are very hard interviews.

FLATOW: Are they?

Dr. TYSON: Yeah, because they can come at you from any direction. It's not just the content I'm bringing to the table. It's - I've got to bone up on my social mores, on international politics, on all the hot subjects that fill the 24/7 talk show circuit. I've got to be ready, because they could plug that back into me. And it's like a tennis serve, right? Because they're quick, they're witty, they're smart, and I've got to be ready for anything that they send out.

FLATOW: Including a Rubik's cube.

Dr. TYSON: (Laughing) And yes, a Rubik cube. You saw that, right? There was a Rubik cube moment on…

FLATOW: How fast did you do that?

Dr. TYSON: Well, I'm a - you know, I carry - I'm card-carrying geek, so if you're a geek, you don't let a unsolved Rubik cube just sit there. It's a duty to solve it, all right? But I'm not one of these whiz kids at it. So, I'm average - anywhere between three and five minutes.


Dr. TYSON: The difference with that particular cube, it had a configuration that was curiously unfamiliar to me, and I had to keep backing out and going back in. So, that took me about seven minutes and - but that's what lingered on in the green room when they were all trying to go home, because I was the last guest of the day. And that's what triggered this.

FLATOW: You do have a trouble - you do have a vice that you like to talk to people.

Dr. TYSON: Well, I…

FLATOW: You love - I see you all the time. It doesn't matter who it is - somebody stops you on the street, somebody in a green room, somebody at a lecture - you love to talk to people and tell them what you know.

Dr. TYSON: Well, let me reverse that a little. I'm not going to deny that, but let me put the cart behind the horse. I don't (Laughing) grab people on the street and start talking to them.

FLATOW: (Laughing) No, I mean…

Dr. TYSON: I'm minding my own...

FLATOW: Now, you'd be arrested in New York if you did that.

Dr. TYSON: I mind my own business, and then someone comes up to me - hey, are you the guy with the…

FLATOW: Right, right.

Dr. TYSON: Can you tell me more the about the black hole? Then, sure, I got you…

FLATOW: But there are a lot of famous people who wouldn't do that is what I'm saying.

Dr. TYSON: Oh, well.

FLATOW: They would say, you know, I got a meeting. I got to be there yesterday, but you do take the time.

Dr. TYSON: If I have a meeting, I'll bring them to the meeting, and (Laughing) I'll keep talking to them.

(Soundbite of laughter)

FLATOW: I see you do that. And you use humor in your book a lot, too - in "The Pluto Files."

Dr. TYSON: Oh, well, because I think the universe is a funny - is hilarious place. In fact, I'm might actually quite deadpan in this book, as the writer of it, because I enclose in this book a lot of samples of the humor that came out after Pluto was demoted. For example, there is a comic by Chas Ullman(ph) where he draws Pluto as just this orb on the street corner - a sad looking orb - holding a beggars cup. And you're saying, why? Well, Pluto's holding up a sign that says, victim of downsizing. (Laughing) And it's the cutest thing. It's great.

There's an article - excerpts from an article in here from The Onion. We all know and love The Onion. And it says, NASA plans to send a consoler probe to alert Pluto of the demotion. So, I was so enchanted by the public's reaction on all levels, not only, like I said, from the school children but also from humorists, that this is a collection - a guided collection of, not only sort of the history of Pluto and the back story, but a celebration of the public's fascination with this scientific quest. I feel honored and privileged to work in a field that has this much public participation.

FLATOW: And there is a tremendous interest in this stuff.

Dr. TYSON: Yes.

FLATOW: And there - the gatekeepers don't allow it out there. You watch the news, you never hardly see any news about science, physics, whatever. People love it.

Dr. TYSON: They love it.

FLATOW: They love to talk about it.

Dr. TYSON: It's there. It's there. Yeah.

FLATOW: And where do you think - what do you think about all this - the new direction this administration is taking in space research?

Dr. TYSON: I think it's hopeful. You know, he's got a lot on his plate, and what I hope is that he doesn't say, here are some problems we need to put Band-Aids on, because some - yes, you need some Band-Aids, but at some point, you want to sort of solve what's causing the sore in the first place. And sometimes that takes an investment foresight that needs to have a vision that goes beyond an election - a re-election cycle.

So, this requires investments in the science agencies - the National Institute for Health, the National Science Foundation, NASA. These are agencies that represent our future technological posture in the world. And in the 21st century, there's no greater engine of economic growth than innovations in science and technology. And if we don't understand that, the rest of the world certainly does - the rest of the developing world - and that's how they're investing their money. And so, we can keep telling ourselves that we're leaders in the world. And that works until everyone else passes us and we just recede to insignificance. At that point, you might as well just move back into the cave, because that's where everyone'll see us.

FLATOW: Yeah. Talking with Neil deGrasse Tyson, author of "The Pluto Files." This is also the - let's see - well, let's see who've we got on the phone. 1-800-989-8255. Let's go to - take the first call at the top - Troy in Iowa City, Iowa. Hi, Troy.

TROY (Caller): Yes. I got a question for you. As you know, some stars circle other stars. Would that make that one star that circles that star a planet? And if so, maybe Jupiter is not a planet, it is a star that didn't start.

Dr. TYSON: Well, that's a...

TROY: So, now you have - now you're down to another one.

(Soundbite of laughter)

FLATOW: That's another can of worms.

Dr. TYSON: Would you let us get over this hump first?

(Soundbite of laughter)

Dr. TYSON: No, actually we've got the top end figured out, and that one is sort of unambiguously resolved. If it's possible to have so much mass - oh, what I didn't highlight is that to be round requires that you have enough mass, that your gravity makes you round, because there are small objects out there, like Mars' moons, Phobos and Deimos - they are so small, they don't have enough gravity, and the rocky structure of those moons is responsible for the shape they have. So, they look like Idaho potatoes. So, to require that you're round is a statement that you're at least above a certain size threshold.

The upper end of planets - that's - that one's easy. We had that one resolved for quite some time. It's possible to have so much mass that the pressures in your core will trigger the onset of thermonuclear fusion. And it's the fusion reaction in the core that we define as the birth of a star. So, the real fuzzy zone is can you be a brown dwarf? Brown dwarf is like a star that's not quite a star, but clearly has properties closer to stars than planets. That's where the fuzzy zone is right now, and we've got some top people trying to work that one out.

FLATOW: Question here from Twitter, from Novinator(ph) - how could Mars ever be terraformed, considering it no longer has a magnetic shield from the solar wind? And let's talk about that. Where did - you know, there are people who talk about, well, we've used up this planet or we may have a nuclear explosion. Wouldn't it be better to just invest our money getting off of here, terraforming Mars and leaving this behind?

Dr. TYSON: Whatever it would cost to ship a billion people to a terraformed Mars will certainly be vastly more than fixing Earth. (Laughing) I can tell you that right now. Now first, we can barely predict next week's weather. To believe that some time in the foreseeable future we're going to terraform Mars, turn Mars into an oasis where we can live on it again? I'm just not convinced of this.

Now, the concern that Mars does not have a magnetic field and you need some - it doesn't have an ozone layer - you need some things that would protect us here on earth. A lot of that's resolvable. I mean you can have radiation shields, you'd just live indoors, whatever. Life would be different on Mars, even if it were terraformed. I don't think that's the - that's a showstopper. But the urge to be a multi-planet species is high, and it can protect the species if something bad happens on one planet and on another. You protect the species, not the individual.

But if an asteroid's coming, I'd rather just deflect the damn asteroid and - rather than say, oh, half of you move here, so that when we die, you'll still be alive. (Laughing) That's not a satisfying solution to me. I'd rather use our clever engineering, our clever understanding of science, find solutions to the viruses that might threaten us, bring world peace, so that we don't kill ourselves with our nuclear weapons, and deflect the asteroid when it comes in.

FLATOW: Do you think you're going to be doing more of these kinds of messages as your career goes ahead?

Dr. TYSON: Messages?

FLATOW: Of education, in terms of education, of science, of...

Dr. TYSON: I think science literacy is important and so should everybody else. I wish I weren't - I'm not the only one speaking this way, but I'm not saying this selfishly, I'm saying this for the greater interest of the individual and of the nation. The more science literate you are, the less susceptible you will be to someone who might use science literacy in the role of taking advantage of your ignorance. I mean that's - science literacy is a vaccine against being exploited in society.

I had a little letter in to the editor in the New York Times back when the financial crisis first hit. Everyone was talking about predatory lending practices of the banks and this - and I thought to myself, well, suppose the borrower was just simply a little more mathematically literate and could calculate the effect of a variable interest rate on their monthly payments. They could say, you know, you want to give me this loan, but I don't trust that I can sustain my payments on this, so thank you, but I decline. Then you wouldn't have this problem, because the math literacy would have prevented it in the first place. And so - so, it's easy to blame problems on other systemic issues in society when so much of it could've just been avoided.

FLATOW: Or if you just had some critical thinking behind you - that I'm going to look at this and think it critically.

Dr. TYSON: I count them as the same mental talent, yes.

FLATOW: You count them as the same. Mm hmm. 1-800-989-8255, let's see if - let's go take the phone calls. Go to Graham in Norman, Oklahoma. Hi, Graham.

GRAHAM (Caller): Hi, thank you for taking my call.

FLATOW: Hi there.

GRAHAM: I was curious how you feel about the possibility of finding a planet that could not only sustain life, but has significant evidence of it?

Dr. TYSON: Well, that would be extraordinary. And by the way, such a planet might even be Mars. Mars recently - just a few weeks ago - had evidence for methane - methane seeping out from a cliff face. Methane - you can make it by non-biotic means, but one easy way to get it is bacteria functioning in the absence of oxygen, much as what happens in - deep in the intestinal tracks of farm animals. So, methane is an active ingredient in farm animal flatulence, by the way.

(Soundbite of laughter)

Dr. TYSON: So - not that you asked, but I thought I would share that fact, because these are very active anaerobic bacteria…

FLATOW: Right.

Dr. TYSON: Deep in the digestive tract. Mars - we know it has no surface water. Where did the water go? It once had water - it's got dried riverbeds and floodplains and lakebeds - all dried. We think the water went below the surface. There may be pockets that are kept liquid by some local heating mechanisms or pressure - whatever. If that's the case, since every place on earth where you find liquid water, we find life, perhaps these are beds of thriving organisms - likely microbes, rather than Martians with antennae, but any kind of life at all would transform our understanding of biology.

FLATOW: All right. Let's see if we can get another question in from Twitter, from CTorgitt(ph) and she says, I'd love to hear Neil talk about - more about engaging kids, getting them out the front door in real versus virtual world - getting them into the real world versus just sitting there in the virtual world - experimenting, I guess.

Dr. TYSON: Well, some - yeah, some of that is just the bias of the difference in generations. I mean, yeah, my kids, when they're not on the computer on Facebook, they're on YouTube, and they never leave the technology. And so, it's easy to criticize that and say, why don't you, like, go out and smell the roses? But there's no denying the access that the Internet provides, the world of content that's out there - on science, on nature, on - just information and politics. So, I'm not so quick to say, yank them away from the computer, and put them out in the park. I'm just - I don't like judging across generations. What I'd rather do is take what it is they are immersed in and try to exploit that to the greatest gain.

FLATOW: 1-800-989-8255 is our number. I'm Ira Flatow. This is Science Friday on NPR News, talking with Neil Tyson, author of "The Pluto Files." Where do you go to next? I mean, more books, more research, or…

Dr. TYSON: Oh, just quick - a quick follow up to that.


Dr. TYSON: Think about the fact that we now have writing. There was a day when writing was invented where the older generation said, that's the end of memory, because now you just write it down. You don't have to remember it anymore. What's the world coming to? (Laughing). So, I…

(Soundbite of laughter)

FLATOW: (Laughing) It reminds me…

(Soundbite of laughter)

Dr. TYSON: So, I'm not - I don't like judging the next generation's technologies. I just don't.

FLATOW: Yeah. It reminds me, when the Berlin Wall came down, people were saying, was the end of history, like…

Dr. TYSON: Oh, right. Excuse me.

(Soundbite of laughter)

FLATOW: Because nothing can happen.

Dr. TYSON: Yeah, yeah.

FLATOW: There are no more problems going to happen.

(Soundbite of laughter)

Dr. TYSON: People - unfortunately, somebody's always putting up a wall somewhere in the world.

FLATOW: Well, is that true in science? Can you predict where - you know, trends - what are the trends in planetology or space now?

Dr. TYSON: Yeah. In astrophysics…

FLATOW: Astrophysics.

Dr. TYSON: We have - the reason why we have pretty good prediction of what is possible to discover is because a lot of it flows out of the hardware that we're bringing to bear on the problem. So, we want to send a laboratory to Mars, which would be the next best thing to sending a geologist with a geology lab. And so, when that happens, there's a whole other kinds of discoveries we expect to make. Until that happens, we're not going to make those discoveries.

There's a spaceship en route to Pluto right now, and it's going to get there in 2015. It will learn more about Pluto's surface structures, its composition, the Pluto-Charon - the name of its moon - the Pluto-Charon system, other objects, other icy bodies in the outer solar system, with a level of detail impossible with telescopes from the ground. So, in my field, we know where the discoveries are coming because that is the funding that enables the hardware.

FLATOW: Should we be sending people to any of these places?

Dr. TYSON: I - not - people are expensive to send into space, because they usually want to eat and typically they want to come back home when you're done. Whereas robots - you just send them out there, they're fine.

FLATOW: Right.

Dr. TYSON: Last I checked, they're just fine.

(Soundbite of laughter)

Dr. TYSON: You can leave them out there, they're fine.

FLATOW: They don't protest much not coming home.

Dr. TYSON: The value of humans in space is what it does to the educational pipeline, because if you just take your cues from the 1960s, when we were going to the moon, the Apollo astronauts were icons in our culture. That can happen again when we select the first class of astronauts who will be the Mars explorers. You know the media's going to go to their elementary school. They're going to interview their science teachers. It'll create an entire other adventure that the educational pipeline can celebrate. And that has value beyond a particular scientific discovery.

If the value is measured in the inspiration that no agency in the world has the power to bring the way NASA can bring, it will create a mood and attitude, a sense of dreaming about tomorrow. Whatever happened to the books where people talked about Tomorrowland and the bubble car? We stopped writing them. Why did we stop writing them about when we stopped going to the moon? I don't think that's just mere coincidence. I think there's a cause and effect there, because the space program gets you thinking about tomorrow. And I want to live in a country where tomorrow is just as much on the plate as today. Without it, just - you just live day to day.

FLATOW: And living day to day is made a lot more pleasurable by having you here, Neil.

Dr. TYSON: Well, thank you, Ira.

FLATOW: And always good to see you, and you're always - being in New York, you're always invited to drop by our studios anytime you're in town.

Dr. TYSON: Well, thanks for the standing invitation.

FLATOW: Neil deGrasse Tyson, author of "The Pluto Files." It's a terrific book. You know, it's a great book for Valentine's Day gift - coming up. You want something to get for your loved one, it's terrific.

Dr. TYSON: (Laughing) From Pluto with love.

FLATOW: From Pluto with love. It's got a lot of funny things in it - a lot of cartoons, a lot of stories, a lot of humorous anecdotes, but it's also got a lot of education in it. So, thanks, Neil, for joining us today.

We've run out of time. I'd like to thank - well, Greg Smith composed our music today, so thanks to him. We also had help from NPR librarian Kee Malesky. If you have comments or questions, write to us at Science Friday, 4 West 43rd Street, Room 306, New York, New York, 1-double-oh-36. Also, folks are still hanging out Twittering. Our Twitter is @scifri, and they're still schmoozing over there and our island, so - in Second Life and get a free T-shirt and talk to them. The group is out there having fun. Have a great weekend. We'll see you next week. I'm Ira Flatow in New York.

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