Dr. Mike Brown, a professor of planetary astronomy at the esteemed research institute, joined us to talk about his most well-known accomplishment—contributing to the declassification of Pluto as a planet—as well as his own discovery of a massive planetoid in our solar system.

Our contributors were fascinated by Brown’s work and his techniques and peppered the professor with question after question. The following is an extended, edited transcript of their discussion.

Phil Torres, “TechKnow”: Dr. Brown, you’re probably best known as the man who killed Pluto. Why’d you do it?

Dr. Mike Brown: You know, the obvious answer is that [Pluto] really had it coming. If it wasn’t me, somebody else was gonna do it and it just needed to happen. How I Killed Pluto and... Mike Brown Best Price: $1.75 Buy New $7.00 (as of 11:35 EST - Details)

PT: And what happened? Tell me the story.

MB: The short version of the story is that Pluto never should have been called a planet in the first place. It was really just a big mistake because everybody it was as big as Jupiter when it was first discovered. Now it’s known just how small it really is—smaller than our moon. And there are thousands of other things out there just like it in our solar system. [There’s an] asteroid belt that’s between Mars and Jupiter and we don’t call any of the things in the asteroid belt planets. Although, people did back in 1801, but they got over it. Out beyond Neptune there’s this other belt of all these small bodies that are flitting around the outside edge of the planetary system.

PT: What is special about that belt?

MB: These objects are on the very outer edge of the solar system, and they have been in sort of cold storage for the last four and a half billion years. So if you can figure out what they’re made out of, figure out where they came from, figure out why their orbits are the crazy orbits that they have—you are basically looking back at a fossil record of the beginning of the solar system.

Shini Somara, “TechKnow”: Our understanding of the solar system seems to really depend on where technology is at.

MB: That is absolutely true. The reason that we started finding these objects just in the last 15 years was because of the development of digital cameras—the same digital cameras that all of us now have in our pockets on our cell phone. Now we can take pictures of vast areas of the sky, very quickly process them, find the small things that are moving across the frame, track them down, go to the big telescopes which also didn’t exist 20 years ago and really start to make progress understanding this region.

PT: All of this effort to look at the edge of our solar system. Why is that important?

MB: It’s really the key to understanding how our solar system put itself together, how the planets formed, how they rearranged. If you have 8 planets, it’s not enough to really be able to put the story together very well. But you have thousands and thousands of these small bodies—and so small bodies are in a sense like the blood spatter on the wall after some massive murder in the outer solar system. The planets have all been moved away, but [with] that “blood spatter” you can read exactly who did what to whom. Celestron - PowerSeeke... Best Price: $114.60 Buy New $149.95 (as of 09:45 EST - Details)

PT: So if Pluto isn’t a planet, then what is it?

MB: The official term for what pluto is is a dwarf planet. I didn’t come up with that one. I think it’s a pretty silly word, but that’s what it is.

PT: What would you call it?

MB: Planetoid is actually a nicely serviceable word—it’s smaller than a planet, but kind of looks like a planet.

PT: When you came out with this announcement about Pluto, did you face much resistance within your field or in the public?

MB: I didn’t really come up with an announcement about Pluto—this was a decision of the International Astronomical Union. I pushed hard to make sure they made the right decision. I had found an object that’s more massive than Pluto, and so what part of the discussion was—what do we do with this object that I found? Is it a planet? Is it the 10th planet? If I had not stood up and said, no, this thing I found is not a planet, don’t be ridiculous—and neither is Pluto—I think that really helped people, astronomers make the decision. Was there a lot of resistance? Sure. There still is. I got hate mail from young children for many years. I don’t get as much now because young children think it’s funny that they know Pluto is not a planet and their parents don’t. So, the children are on board. I get obscene phone calls late at night. That started more recently, and it’s always on like a Friday or Saturday night. So I’m fairly sure it’s the same children from whom I got the hate mail, and they’re now off in college at their first frat party and they think it’d be really funny to call me up and yell at me. I save them all, because they’re hilarious. And there are definitely a very small but vocal set of scientists who don’t like the idea, mainly because they studied Pluto and they feel like saying it’s not a planet means that it’s less important. I think that they are looking at things the wrong way. I think it’s better to classify things correctly—and then let’s explain why Pluto’s [still] actually really quite an important thing to study.

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