NASA's $700 million New Horizons spacecraft will arrive in the Pluto system in mid-July after a nine-year 3 billion mile flight that started before Pluto was demoted to dwarf-planet status.
But thanks to the Hubble Space Telescope, we already some fascinating stuff about Pluto and its five known moons. The Pluto system consists of four tiny satellites —Nix, Hydra, Kerberos and Styx — orbiting a "binary planet" comprised of Pluto and its largest moon Charon. They’re locked in odd rhythmic gyrations in a dance unlike anything in our solar system.
What makes it so odd is that there's a double set of dances going on. First, Pluto and Charon are locked together in their own waltz "as if they are a dumbbell" with a rod connecting them. It's the solar system's only binary planet system, even though Pluto and Charon aren’t technically planets.
But Pluto and Charon aren't alone, and that's where it gets more complicated. The four little moons circle the Pluto-Charon combo, wobbling a bit when they go closer to either Pluto or Charon, being pushed and pulled by the two bigger objects.
Those four moons orbit Pluto-Charon in a precise rhythmic way, but with a twist: They also interact when they near each other. So it seems like they all dance to one overarching beat but not quite in the same way, just doing their own thing.
Nix and Hydra exhibit chaotic rather than synchronous rotation, meaning they don't always keep the same side facing Pluto-Charon — and that it's very tough to predict their rotational movement. (Nearly every other moon in the solar system, including Earth's, is a synchronous rotator.)
If you lived on Nix, you would not know if the sun is coming up tomorrow; it is that extreme. You'd have days where the sun rises in the east and sets in the north.
Thanks for stopping by. I post here every first and third Thursday of the month. Don’t miss my June 17th blog as I’ll be posting on the James Webb Space Telescope.