PT: You also found the largest object in the solar system in the last 150 years. What was it?
MB: It’s the most massive thing—right now we don't know if it is bigger than Pluto or exactly the same size or a little bit smaller. Eris was the object that led to all this debate and eventual demotion of Pluto. It’s very far away, about three times further away than Pluto is right now, but it comes in really close. It’s got a moon around it and a surface covered in methane. It’s got nitrogen in its atmosphere, and most of that atmosphere is frozen. It’s this fascinating little world. I don't think the fact that its a dwarf planet makes it any less interesting.
SS: Are you expecting to find a larger planetoid than Eris at some point?
MB: Yes, it would shock me if Eris is the most massive thing out there.
SS: It seems like the more advanced our technology becomes, the larger our outer solar system seems to become as well.
MB: It's certainly true. In the next 10 years, we'll find many many objects driven by new telescopes that are coming online in South America that have even bigger cameras on them. I think we're gonna start to detect things even farther out.
Crystal Dilworth, “TechKnow”: I love the story of the de-classification of Pluto, because I think its a great example of how new information can really change the entire idea that a group of scientists have about something that they've taken for granted to be true for a really long time.
MB: The interesting part of the grumblings about Pluto not really being a planet started when Pluto was discovered, but they eventually got pushed to the side. Everybody knew that this was something that would be a very difficult public conversation to have. What finally made the discussion have to happen was this discovery of Eris—either there’s gonna be a 10th planet, or if you really wanted to make sense there would have to be 200 planets. Or there’s gonna be eight planets. Finally that forced astronomers to actually have a rational conversation about what to do. Classification matters—as scientists, this is the first thing we do when we are confronted with an observation of a new phenomenon that we don't know. We classify things, and we use that classification to figure out what questions to ask, how else to investigate it. If we had been aliens walking into the solar system for the first time, no alien would put Pluto with these other things. The aliens would say, you know, there’s terrestrial planets, and there’s giant planets, and there’s asteroid belts over here, and there’s the stuff outside there.
SS: It’s really impossible to imagine that we're the only life form. Do you ever think about discovering other life forms?
MB: I think a lot about the question. I don't think about discovering it [myself], but I think about the question a lot. I don't even think, the right question is, “Are there other life forms out there?” Because the answer has to be yes, there’s just no possible way that the universe could exist in such a way in its vastness that we are the only intelligent life form that developed. That would be crazy. The important question is: Is it common or rare? Are there intelligent life forms at every star that we look up at in the sky? Or in our galaxy, we’re the only ones and you have to go to the next galaxy so you can find the other one. We have no idea what the answer to that is. If you have the right conditions, there’s a 100 percent chance that you'll have life. We find answers to questions like that by looking in our own solar system.