Pluto's Moons, Nix and Hydra, Wobble Chaotically, NASA Study Reveals

Scientists may have spotted Pluto's moons in the highest detail yet. Researchers have taken a closer look at Pluto, Charon, and the four smaller moons that orbit this pair and have learned that the moons have chaotic and unpredictable rotations.

"Like good children, our moon and most others keep one face focused attentive on their parent planet," said Douglas Hamilton, co-author of the new study, in a news release. "What we've learned is that Pluto's moons are more like ornery teenagers who refuse to follow the rules."

As Pluto and Charon interact with one another, they create an imbalanced and dynamically shifting gravitational field. This sends the smaller moons tumbling in unpredictable ways. Because the moons are roughly football shaped rather than rounded spheres, this effect is amplified.

While the rotational motions are chaotic, though, the moons follow a surprisingly predictable orbital pattern. Three of them, Nix, Styx and Hydra, are locked together in resonance. This means that their orbits follow a clockwork pattern of regularity.

"The resonant relationship between Nix, Styx and Hydra makes their orbits more regular and predictable, which prevents them from crashing into one another," said Hamilton. "This is one reason why tiny Pluto is able to have so many moons."

The new research reveals a bit more about how the moons look, as well. Kerberos is dark as charcoal, while the other moons are as bright as white sand. This reveals a bit more about this system and, when New Horizons soars closer, the researchers will receive new images that will tell them even more about the Pluto system.

"We are learning that chaos may be a common trait of binary systems," said Hamilton. "It might even have consequences for life on planets orbiting binary stars."

The findings are published in the journal Nature.

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