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Planet Or Not, Pluto's Getting A Visitor


This is SCIENCE FRIDAY. I'm Ira Flatow. Next week marks the 82nd anniversary of the discovery of Pluto. And depending on whom you ask, Pluto is or was our ninth planet. Pluto's status as a dwarf planet, a mere Kuiper belt object is still a topic of hot debate. But planet or not, Pluto is getting a visitor. The New Horizons Mission was launched in 2006, and it's headed out on its three-billion-mile road trip to the Kuiper belt. That's a long way, but the spacecraft is making good time. It's travelling at about 34,000 miles per hour and scheduled to fly by Pluto in 2015.

And if the mission's leaders have their way, that's about the same time that they would like the U.S. Postal Service to roll out a new commemorative stamp honoring Pluto. We'll talk about that in a few more minutes. But first, here to talk to me about Pluto and the mission to visit it is Alan Stern. He is principal investigator of the New Horizons Mission to Pluto and the Kuiper belt, and he's based at Southwest Research Institute in San Antonio. Thanks for talking with us today, Dr. Stern.

DR. ALAN STERN: Hi, Ira. How have you been?

FLATOW: Hey, nice to have you with us. You know, depending to which part of the country you go to - I remember going - we were just out in Arizona, and you talk to any scientist in Arizona, and Pluto is still a planet out there. And I guess it's in your...

STERN: You know, it's not just in Arizona.

FLATOW: Yeah. I was just going to say that. It's in your neck of the woods, too.

STERN: Well, you know, Pluto's oftentimes maligned. But, you know, people don't realize it's a big place. If you drove around the equator of Pluto, it's as far as from New York City all the way to Hawaii.

FLATOW: Mm-hmm. And so there are die-hard Pluto advocates who are going to continue to push that - and continue not to believe that Pluto is not a planet.

STERN: Well, you know, we've discovered in the last 16 years that the solar system is littered with a smaller class of planets called dwarf planets.

FLATOW: Right.

STERN: And some people were having a hard time accepting the fact that what they were taught when they were children, that there were only, you know, a small number of planets, isn't the case. It's too bad. Just like Galileo discovering there are so many stars, you can't name them all, there are so many planets that you can't name them all. And we just need to get used to the data.

FLATOW: Yeah. Let's talk about the mission that was launched in 2006. How far have we gotten? Where is the spacecraft at this point?

STERN: Yeah. Thanks for asking. New Horizons is now about two-thirds the way from here to Pluto. It's out between the orbits of Uranus and Neptune and headed to an encounter just over three years from now.

FLATOW: Three years from now. And I read somewhere that this was the fastest man-made craft ever built. Is that true?

STERN: We are the fastest spacecraft ever launched. Set records - speed records for reaching the orbit of the moon in just nine hours, reaching Jupiter in just 13 months. Compare that, for example, to Galileo, the NASA Galileo mission, it took six years to get to Jupiter. We are speeding across the solar system.

FLATOW: And what happens when you get there? What is the mission?

STERN: The mission is two parts. The first part is to reconnoiter the Pluto system, Pluto and all of its moons, during the early months and middle months of 2015, a (unintelligible) calendar. And then we will go on deeper into this new region of the solar system, the Kuiper belt, with the intention of flying by one or, very possibly, two small Kuiper belt objects roughly the size of counties, things that are, you know, the building blocks of the planet.

FLATOW: Mm-hmm. And how is Pluto discovered, this being the 82nd anniversary? How - what was the process? Was it searched for? Was it by accident?

STERN: It was searched for, in fact, for about 25 years. From 1905 to 1930, various astronomers looked for what they then called Planet X. And a very young man working for Lowell Observatory, Clyde Tombaugh, who, at that time, didn't even have his doctorate in astronomy, made the discovery largely through just hard work in the winter of 1930.

FLATOW: Mm-hmm. And he didn't have modern telescopes, but that was a pretty good telescope. It's still around.

STERN: He - that telescope does still exist. The telescope's pretty good, but what's most amazing is, you know, just the persistence and the careful attention to detail, because what we would now turn over to computers for mind-numbing data analysis, he did by hand and by eye in 1930, comparing one photograph to another to look for moving objects with, you know, ridiculous numbers of stars to filter out in his mind and look for the find. And he never reported a false discovery. All the time that he was working for Lowell, the only time he came to his boss, he'd actually found a planet.

FLATOW: Now, I understand that some of his ashes are actually on the spacecraft.

STERN: That's true.

FLATOW: And is there a plaque or an urn, or how is it being carried?

STERN: Yeah. He requested that after he passed, that he be cremated, and then if there was a mission to Pluto, that some of his ashes be included. And we honored that request. About an ounce of Professor Tombaugh's ashes are on the spacecraft in a small, metal box that's welded to the spacecraft, which is actually used as a small balance weight. There's a plaque next to it about his discovering the Pluto system, and along with some other commemorative items. They're on their way not just to Pluto, but out of our solar system, into the stars.

FLATOW: Interesting. 1-800-989-8255 is our number. The Pluto New Horizons team is also on another mission. I mentioned it before. They're hoping to get the U.S. Postal Service to issue a commemorative stamp honoring Pluto and the New Horizons spacecraft. And you can see the concept for the stamp on our website. It's sciencefriday.com. And there's a link to a petition there, as well. And the proposed stamp, if you look at it, it shows the spacecraft, and it's set against a backdrop of Pluto. And here to talk more about it, better to describe it than I can is the artist who designed it. Dan Durda is an astronomical artist. In his day job, he's a principal scientist at the Southwest Research Institute, and he's designed several images for the New Horizons missions. Welcome to SCIENCE FRIDAY, Dr. Durda.

DR. DAN DURDA: Thanks, Ira. Great to be with you.

FLATOW: Tell us about this petition.

DURDA: Well, it's Alan Stern's brainchild. Back in the 1990s, there was a Exploring the Planets stamp series that was commemorating the very first missions to various planets. And poor little Pluto, back then, just simply had the words not yet explored. And that sort of stuck in the craw of the folks who were trying to get a mission to go to Pluto. And so Alan vowed way back then that if we ever had a mission to go to - off to Pluto, it was going to have a new stamp associated with it. And so we've been working very hard to get this new stamp issued.

FLATOW: The first stamp is on the spacecraft, correct?

DURDA: The first stamp, Alan actually had put on the spacecraft. That's correct. There's a sample of it there, kind of a little bit of a poke in the eye to the general idea.

FLATOW: And what does it take to get a new stamp, then?

DURDA: Well, there's a standard process through the U.S. Post Office website. There's, effectively, a short, written proposal that goes in, along with an actual bit of concept art for the stamp, at least for the idea for the stamp, that you'd like to propose. And then also associated with that is a petition process to show that there's, you know, interest on the part of the general public in having a stamp like that.

FLATOW: Mm-hmm. 1-800-989-8255. A lot of listeners wanted to call in. Let's take a few calls. Philip in San Rafael. Hi.


FLATOW: Hi, there, Phil. Go ahead.

PHILIP: I just have a simple question. Pluto is so far away from the sun. It must be very dim out there. There's not much sunlight. So will the New Horizons spacecraft be able to get (technical difficulties) the same kinds of spectacular photographs that, you know, Voyager and other satellites have gotten?

FLATOW: Alan, what do you say?

STERN: Yeah. The answer's yes. The sunlight's about a thousand times dimmer than it here at high noon. It's about like twilight conditions on the Earth, actually, and all of our cameras and spectrometers are designed to operate at that light level. In fact, they're much better at it than the Voyager cameras were, so hold onto your hat. We expect to deliver eye-popping imagery.

FLATOW: Wow. We'll look forward to that. Rona in - well, let me get Rona on here. Rona in Marble Canyon, Arizona. Hi, Rona.

RONA: Yeah, that's right, Ira. I've called before. Yes, I think that Pluto should have its own stamp. But you better use the mail, not just the emails, if you want to have a new stamp.


FLATOW: And there won't be much - there won't be a mail system left, is what you're saying to use it.

RONA: Well, there's a plan. The head of the post office and the union have a plan, but Congress has to pass it.


RONA: Ah-ha. Anyway - and may I say that I'm a loyal and avid listener. And I'm going to be 80 tomorrow, Ira.

FLATOW: Happy birthday.

RONA: And I listen to SCIENCE FRIDAY. Every time I would say, oh, I really want to live a long time so I can be around when all these wonderful things happen.

FLATOW: All right. Well, we'll talk to you 80 years from now, again, hopefully.

RONA: Oh, I don't think so.


FLATOW: Happy birthday, Rona.

RONA: But I'm with you.

FLATOW: Thank you. Thank you. That's very nice...

RONA: Thank you. Bye.

FLATOW: ...of you to say. 1-800-989-8255. Can you - Dan, can you describe the stamp for us a little bit more?

DURDA: Oh, sure. Yeah. So we wanted to show the excitement, really, of the New Horizons encounter with this really geologically, meteorologically interesting world. And so I, working with Alan, tried to come up with a bit of a concept that showed that this is going to be an interesting world. It's not just some boring ice ball. It's known to have some pretty significant color and brightness contrast across the surface that implies that there's going to be some interesting geology to see. Alan can describe a lot more of the detail of the - what we know about the interesting atmosphere that's in - at this small world. So we've put a lot of that in the artwork, as well.

FLATOW: Alan, have - has there been a great deal of backlash since Pluto was officially taken out of the realm of planet?


STERN: Yeah. You might remember in 2006...

FLATOW: I certainly do.

STERN: ...when the astronomy community made their quick vote on short notice that the planetary science community came back, hundreds of experts in planetary science, who said, no, wait a minute. We're not buying that. We know a planet when we see one. Astronomers should stay out of planetary science. Apparently, they don't know what they're talking about. And since then, what I found is that most people you talk to about what is and isn't a planet, I think it's pretty clear the tide has turned, and people appreciate that these small planets are planets, too. They have all the same attributes.

For example, Pluto has not just geology and an atmosphere and a system of moons, but polar caps and seasons and all the things that you normally associate with a planet. And so just like a Chihuahua is still a dog because it has all the attributes of a dog, these smaller worlds turn out to be a big surprise, a wonderful discovery, actually, that the outer solar system is littered in planets that are thousands of miles around, but still smaller than the Earth and gargantuan Jupiter, and that we need to count them, too, in the population of planets because, after all, they have all the attributes of planets.

FLATOW: This is SCIENCE FRIDAY, from NPR. I'm Ira Flatow, talking with Alan Stern and Dan Durda. Our number: 1-800-989-8255. So, Alan, you think the tide is turning? You said the tide is turning a little bit. They're not going to reverse a decision, do you think?

STERN: Well, I don't know. The astronomers can do what the astronomers do, but they're not really in their realm of expertise when they're talking about planetary science. Although - planets are in space, but they're not stars. They're not galaxies.

FLATOW: So your argument is that we should not leave the designation of a planet to astronomers? We should talk more to terrestrial scientists?

STERN: Well, no, the planetary scientists, people who actually study planets rather than faraway galaxies, for example. But my real point to you, Ira, is that the IAU sort of meddled in an area where they're not particularly expert and further came up with a poor definition. In fact, by the IAU's definition, even in Earth, out in the Kuiper belt, if you put the Earth there, the IAU would not considered it a planet because of the poor definition that they constructed. And by the way, the definition was specifically constructed to limit the number of planets in the solar system. And that's sort of an anti-scientific concept in and of itself, to arrange the answer to be the one you want.

FLATOW: Well, I think we have to have a little smack down, here, between you and your opponents, I think. It could be an interesting discussion because...

STERN: I'd be happy to do something like that if you want to arrange it. That would be fun.

FLATOW: Well, we'll arrange it. I did this years ago with Neil deGrasse Tyson and - oh, now, I'm going to have a senior moment. I can't remember, from Tucson.

STERN: That was Mark Sykes, if I remember.

FLATOW: Mark Sykes, thank you. Yes, it was Mark Sykes and it was very, very interesting. We'll have to revisit it and...

STERN: I remember once doing your show with Mike Brown on this topic. And Mike Brown said to you that we're just not going to be able to have 50 planets in the solar system. His daughter wouldn't be able to remember the names of all of them. And you might remember that I shot back, well then, Mike, I guess we're going to have to go back to eight states, as well, if that's the criteria.

FLATOW: You want to come on with Mike Brown?

STERN: Sure. Name the time and place.


FLATOW: All right. You know, I feel like - well, it is - Arizona and New Mexico, that's Southwest.

STERN: And Mike is a tremendous astronomer, and he's discovered so many things, and he's a very fun and funny guy, and frankly, he should get credit for the planets he's discovered.

FLATOW: Right. Well, we'll bring California in. We'll get Mike Brown. We'll have a - just like in the Old West, we'll have a showdown right here. I don't know if we'll have a street long enough, but we'll make one happen here right on SCIENCE FRIDAY and...

STERN: We'll arrange it to be high noon somewhere. That sounds great.


FLATOW: It's always high noon somewhere.


FLATOW: But before we go, tell us - everything - so is everything normal on the spaceship? It's working well. As they used to say in the space industry, it's nominal, and things are happening just like you expect it on schedule.

STERN: Absolutely. As we also say in the spacecraft business, everything's just tickety-boo. We're a very healthy spacecraft with lots of fuel, lots of power. We're not using any of our backup systems. We are two-thirds the way to our objectives and really looking forward to the encounter. We are heavily involved right now in writing all the observing sequences, the backup plans, all that.


STERN: And we are really looking forward to first-time exploration like people haven't seen in a long, long time.

FLATOW: That will be interesting. Also, there's a lot of work - Dan Durda's work as an artist is on our website. It's sciencefriday.com/art. So we have a sci art site there, right there on SCIENCE FRIDAY, dedicated to science and the arts. There are some great photos - great drawings by Dan and artwork from Dan on there on the website. I want to thank both of you for taking time to be with us.

DURDA: Thanks, Ira.

FLATOW: Thank you, Dan.

STERN: Thank you, Ira.

FLATOW: Dan Durda is a principal scientist at the Southwest Research Institute. He's also an astronomical artist. And Alan Stern is the principal investigator of the New Horizons' mission to Pluto and the Kuiper Belt. That's about all the time we have. Transcript provided by NPR, Copyright NPR.