LIANE HANSEN, host:
This is WEEKEND EDITION from NPR News. I'm Liane Hansen.
(Soundbite of music, "Star Wars Theme")
HANSEN: I bet you can name that film score in three seconds. The movie music, however, will not be discussed in a few minutes. The subjects, instead, will be the sounds, the people and the contraptions behind the audio effects in the "Star Wars" movies. But first:
(Soundbite of movie, "Star Wars")
Unidentified Man: Commence primary ignition.
(Soundbite of special effects)
HANSEN: In the first "Star Wars" movie, the Death Star destroys the planet Alderan. In 2005, Dr. Mike Brown destroyed the ninth planet in our solar system. It was downsized as a dwarf planet, one of many cosmic snowballs in the Kuiper Belt.
Dr. Mike Brown is an astronomer at the California Institute of Technology. His new book is called "How I Killed Pluto, and Why It Had It Coming." He's at Cal Tech's studios in Pasadena, California. Welcome to the program.
Dr. MIKE BROWN (Astronomer, California Institute of Technology, Author, "How I Killed Pluto, and Why It Had It Coming"): Thanks for having me, Liane.
HANSEN: Why did you murder Pluto?
Mr. BROWN: You know, I didn't mean to. I actually set out to find a 10th planet and in that search for a 10th planet, I instead found that there are many, many things like Pluto and it made much more sense to call Pluto part of that group of things rather than those group of things to be a planet.
HANSEN: So, you were looking for a 10th planet. You knew what you were looking for and you found it or was there an a-ha moment?
Mr. BROWN: I knew what I was looking for. I didn't know if it existed, and I spent many years looking and finding things that were small, things that were smaller than Pluto. And I never quite knew if there was going to be something as big as Pluto out there or not. And so there was that very strong a-ha moment when I sat in my office and saw that thing on my screen and knew instantly that this was the size of Pluto.
HANSEN: It wasn't bigger than Pluto? It was...
Mr. BROWN: Well, that's the funny part of the story is that we, at the time we discovered it, we were convinced it was significantly bigger than Pluto and only in the past month, new measurements have shown that it and Pluto are essentially twins.
HANSEN: But that doesn't mean Pluto gets to be a planet again, does it?
Mr. BROWN: No, it doesn't, even though this precipitated the conversation about Pluto, it wasn't because there was something bigger than Pluto that Pluto didn't get to be a planet.
HANSEN: It was just that Pluto didn't have the characteristics of a planet. I mean, did it end up redefining what a planet actually is?
Mr. BROWN: What I like to think we did as astronomers rather than redefining planet or to really discover what the word planet means when people say the word planet. I think in everybody's mind, the word planet means something like the big, important things in the solar system. We all know that there are asteroids, small asteroids going around everywhere. There are also all these small Kuiper belt objects out at the end of the solar system out past Neptune where Pluto is.
And what astronomers finally did is put things in their category. The eight planets are the large dynamically important things in the solar system and everything else is just debris really.
HANSEN: Cosmic debris.
Mr. BROWN: Cosmic debris. And I say that affectionately. I spend my entire life studying and looking for this cosmic debris.
HANSEN: When you found this body called Eris now - you called it Xena...
Mr. BROWN: I did.
HANSEN: ...after the warrior.
Mr. BROWN: Warrior princess.
HANSEN: You betcha. Yeah, you're a big science fiction fan, I bet.
Mr. BROWN: I am. We had a good reason for it. Things bigger than Pluto had always been called Planet X, so we wanted a name that started with an X and we wanted a mythological name. And Xena's, well, it's at least TV mythology, so that's seemed good enough.
HANSEN: Why didn't it stick?
Mr. BROWN: Well, we never actually seriously intended to call it Xena, because if I had actually called it Xena and tried to make it stick, then when my daughter grew up and was 10 years old and learned what I'd actually named it after, I don't think she'd ever talk to me again.
HANSEN: Really? What does Eris mean?
Mr. BROWN: Eris is, of course, the Greek goddess of discord and strife.
HANSEN: Oh, lawlessness?
Mr. BROWN: That's actually her daughter. Eris's daughter is Dysnomia and is the demon spirit of lawlessness in fact, and that's the name of Eris's moon.
HANSEN: Is the International Astronomical Union in charge of the sky?
Mr. BROWN: They are, by international treaty, the group that is allowed to make decisions about naming things and nomenclature in the sky.
HANSEN: So, they were the ones that determined the status of Pluto.
Mr. BROWN: Right. They're sort of like the U.N. of astronomy.
HANSEN: But you know in the state of Illinois Pluto is still a planet.
Mr. BROWN: Only when it passes overhead, which I have to point out to them, it actually never does.
HANSEN: OK, fair enough. Children all over the country got really upset when Pluto was no longer a planet. Did you get any threatening letters in crayon?
Mr. BROWN: I did. I got hate mail from kids - email these days. They're very good at sending emails, so fewer crayon drawings. The crayon drawings I actually tended to get when I discovered new objects. Kids love new objects in the sky. And they draw them. They learn about their colors and about where they are and draw them. And that's some of the most heartening things. The hate emails have now turned into, as the kids have gotten older, they tend to be Saturday 3:00 a.m. obscene phone calls, which are oddly quite amusing.
HANSEN: Now, did you tell your daughter about Pluto or are you going to tell her when she's older?
Mr. BROWN: You know, I had said - and I say in the book - that she's going to learn about planets in school and she's going to come back and I'm going to tell her, hey, did you know that when you were born we thought there were nine or even 10 planets? And she's going to just look at me and say, dad, you are so dumb.
But that's what I said in the book - and it's not true. It turns out that Pluto has seeped into her consciousness, partially because my friends think it's funny to give her pictures of the solar system that include Pluto so she has a big collection of them. But she's now kind of mad at me for having killed Pluto because she knows that I did it, and she kind of likes Pluto.
HANSEN: Yeah, but you go out in the backyard and you look at Jupiter together and it was a big moment for you - and her - when she recognized that Jupiter moved and that's one of the characteristics of a planet, that they're wanderers.
Mr. BROWN: It's something that I think many people never even get a chance to see. They never look up in the sky and know that some of those things up there are planets and then take that second step and realize that the planets really are moving. That's what's different about them from the stars. They're in a different place night after night after night.
HANSEN: What's in the sky tonight?
Mr. BROWN: You know, tonight is actually going to be one of the best nights of the year. The crescent moon has been getting bigger over the last couple of nights and it's been climbing and climbing up into the sky. And if you've been watching it, it's going towards this big bright thing. It's one of the brightest things in the sky. It's to the south, almost straight overhead to the south as the sun sets, and it's Jupiter.
Jupiter is one of the most spectacular things that you can see in the sky. And if you have binoculars, go grab a pair of binoculars, maybe lean up against the wall so you can be extra steady and look and you can see the moons, the four Galilean satellites of Jupiter going around.
It's as if you lived right next to the Grand Canyon and got to look at the Grand Canyon every day. It's one of most wonderful sights anywhere.
HANSEN: Mike Brown is an astronomer at the California Institute of Technology. His new book is called "How I Killed Pluto, And Why It Had It Coming." He's serving a suspended sentence and he joined us from Cal Tech studios in Pasadena, California. Thank you.
Mr. BROWN: It was my pleasure.
HANSEN: Happy holidays stargazing.
Mr. BROWN: Oh, thank you.
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