When I asked Scott Kenyon about his reaction to the news that New Horizons had actually flown by Pluto, his answer wasn't that different from those of the myriad of people I've chatted with about it, from scientists to educators to regular Janes and Joes.
"Well, it's pretty exciting," Kenyon said.
But as a senior scientist at the Smithsonian Astrophysical Observatory in Cambridge, Kenyon — unlike most of us — really understands the gritty details of what's going on. In fact, he and his partner's work helped the New Horizons team figure out the path for Tuesday's historic flyby.
"They had several options, and I think that the numerical calculations that I do with Ben Bromley helped inform them exactly how they should go through the system," Kenyon said.
Kenyon's work centers on the formation of planets. And the dwarf planet Pluto is unlike any other in our solar system. Like many of our planets, it has moons. But unlike the others, Pluto’s largest moon doesn't simply revolve around it.
"Pluto/Charon is this binary planet, so there's a point in between Pluto and Charon that they’re both orbiting around every 6.4 days," he said.
Now, we have some pretty refined theories about binary planet systems and how they form. But they’re theories. Until now, we’ve not seen — or measured — a binary system up close.
"At some point they collided, and Charon skimmed the surface of Pluto, kicking up a bunch of debris, and in skimming the surface it slowed down and became bound to Pluto," Kenyon said.
Some of that debris, the theory goes, became Pluto's four other known moons. Kenyon runs complex mathematical models based on what we know about how Pluto’s system formed. His prediction in a new paper: New Horizons will find even more moons around Pluto and Charon.
"A hundred percent of the time we get more, smaller ones — the typical number is three or four," he said. "It could be zero, but it could be as many as a dozen.
The models are a probability game, with a lot of unknowns. And that's why Kenyon is so excited. Maybe New Horizons will catch a new moon on camera, maybe not. But the data it collects will strengthen his models, as will the photos and analysis of the makeup of Pluto and its known moons. And even if it turns out his prediction is wrong, Kenyon says one thing is for certain, we will unequivocally know more.
"That kind of information, as it’s honed by the mission team will give us a lot of input into how Pluto formed, which in turn will allow us to hone our theories about how all planets are formed," Kenyon said.
How long Kenyon will need to wait is anyone’s guess. New Horizons will soon be sending data back from its flyby, and it will continue to do so for the next 16 months.
