MIKE BROWN: In the last fifteen years I have been exploring the outer part of the solar system, looking for the largest bodies out there, and we found all these objects in the Kuiper belt.
KONSTANTIN BATYGIN: A couple years ago Mike came to my office and said, have you seen this weirdness of the outer solar system?
MIKE BROWN: I showed him some of these alignments that some of the other astronomers had found and he said, “Why don’t you look at it this way and this way?”
KONSTANTIN BATYGIN: It was a gravitational one-way sign towards something distant and something massive lurking in the shadows.
MIKE BROWN: Predicting that there’s a planet in the outer solar system is something that’s been going on for a 150 years. And for 150 years, it’s always wrong.
KONSTANTIN BATYGIN: You often run the risk of being called crazy. We spent six months trying to disprove ourselves.
MIKE BROWN: We needed to be as certain as possible if we were going to say it’s really out there.
MIKE BROWN: Konstantin and I met when he applied for graduate school.
KONSTANTIN BATYGIN: I really did not expect to get in. My grades were not stellar because I was always trying to do homework either backstage or in a van.
MIKE BROWN: He had worked with an astronomer at UC-Santa Cruz who I greatly respect. I was like, this guy sounds like he’s brilliant, I want this guy to work with me.
KONSTANTIN BATYGIN: I actually got the acceptance emailed from Mike Brown. It’s a common name. And then it sort of hit me, oh my god, this is the Mike Brown, and it doesn’t say go away.
MIKE BROWN: Before Konstantin graduated, we were like, um, go off and do a post-doc for a couple of years, but then come back, we would like you to be a professor here. He was like, that sounds good.
KONSTANTIN BATYGIN: Caltech is, is rather small. That’s the key element that allowed us to make this discovery. So I think at other schools, because we do sort of different things—I’m a theorist and he’s an observer—our scientific existence would be somewhat segmented out. At Caltech, we’re thrown together into the same pot. Our relationship is very complimentary.
MIKE BROWN: He just has this insight into the way things work that is, as far as I can tell, his insight is always right.
KONSTANTIN BATYGIN: We are literally a couple doors down from one another, so we talk all the time. It’s like what happens when a great car designer meets a great car tester.
MIKE BROWN: There’s a little beam of sunlight that comes from his door, if it’s open. So I look, like is the sun…. Yep, a little beam of sunlight, so I walk down. There’s no barrier. When I have just one dumb little idea, I can walk down the hall and sit down and start talking about it.
MIKE BROWN: People would walk in on us and, and think that we were just having these heated arguments.
KONSTANTIN BATYGIN: Something began to stick out. The model kept producing orbits that are perpendicular to the plane of the solar system. We thought there could be no such orbits. I went to Mike’s office, said, “I think we’re wrong.” And Mike said, “Let’s look at the data.”
MIKE BROWN: And we looked at the catalog of all the known objects and there were five objects that are indeed perpendicular to the solar system. And I, I looked at Konstantin and I was like, and said, “If they’re in these two locations that we’re predicting, my head’s going to explode.” And so I, I did the calculations quick, press the button so we could plot where they were. And . . .
KONSTANTIN BATYGIN: They fall exactly where the planetary model predicts them to be.
MIKE BROWN: It can only be explained by one large planet on this very eccentric orbit.
KONSTANTIN BATYGIN: This was a true breakthrough moment.
MIKE BROWN: We are the first people in a 150 years who aren’t the crazy people.
It was a huge story, coverage all around the world. Front page of most newspapers.
KONSTANTIN BATYGIN: This discovery captivated the public’s imagination. The hunt for Planet Nine is on.
Like, one of the key elements of the human experience is to explore. And Caltech remains one of the pure institutions where we do things, high-risk things because they’re audacious, and they’re interesting.
MIKE BROWN: When you’re in this very special, small place with very many smart people, ideas that would not come from other places can bubble up from here. It can be supported here.