Pluto’s moons are tumbling in absolute chaos and Hubble saw it

4 Jun 2015

There’s chaos in the furthest reaches of our solar system, as new images from the Hubble Space Telescope appear to show that Pluto’s moons, Nix and Hydra, are completely unpredictable.

From Hubble’s readings, both Hydra and Nix are effectively caught between two powerful gravitational fields that constantly shift between the two dwarf planets that exist in this realm, those being Pluto and its companion planet, Charon.

Because both Pluto and Charon share the same centre of gravity located between them, they are known as a double planet system that, when it comes to Pluto’s moons, causes a ‘cosmic dance’ to occur.

However, this is probably more akin to a freestyle artistic dance rather than something orchestrated, which is only strengthened by the football-like, rather than spherical, shape of the moons.

Pluto’s other moons were also examined by Hubble, revealing little uniformity between them, except for three of Pluto’s moons that are presently locked together in resonance, meaning there is a precise ratio for their orbital periods.

Scales of Pluto's moons

Different scales of Pluto’s moons. Image via NASA/ESA/A. Feild (STScI)

Potential consequences for life in the universe

The surfaces of the moons also came as a surprise to researchers, who had expected to find something more homogenous, but instead found that one moon in particular, Kerberos, was as dark as a charcoal briquette compared with other sand-coloured moons.

One of the co-authors of the paper due to be published on the findings, Doug Hamilton of the University of Maryland, said that the chaotic nature of Nix and Hydra might be more common than we once thought: “We are learning chaos may be a common trait of binary systems. It might even have consequences for life on planets if found in such systems.”

NASA scientists are now eagerly anticipating New Horizons’ approach of Pluto in July to get even closer images than Hubble could ever accomplish.

Simulation of Nix’s rotation

Pluto and Charon illustration via Lunar and Planetary Institute/Flickr

Colm Gorey was a senior journalist with Silicon Republic