In a rare momentum of action, NASA’s Hubble Space Telescope has captured that Pluto’s moons, Nix and Hydra, wobble unpredictably, which the astronomers call sky dance that goes in rhythm though the reason behind is far from it.
NASA’s associate administrator John Grunsfeld attributes is confident that the New Horizons spacecraft destined to cross Pluto in July will throw more light on this cosmic dance.
Essentially, Pluto’s moons wobble as they are embedded in a gravitational field that keeps shifting constantly due to the double planet system of Pluto and Charon, which orbit each other.
Pluto and Charon, being a double planet system, share common gravity center and every time their gravitation field changes, it sends smaller moons tied to them wobbling or tumbling erratically.
Even Pluto’s other two moons, Kerberos and Styx, face similar gravitational change, believe scientists. Mark Showalter said their research found out that there are new constraints on the sequence of events that led to the formation of the system.
Showalter says currently 3 moons of Pluto are locked in resonance. Hubble pictures show that the moon Kerberos is dark like coal, while others are bright like sand. The colours could be due to meteorite impacts, especially Kerberos’ black color.
Nix and Hydra were discovered by New Horizons team from the Hubble Space Telescope images taken in 2005.
Hydra, Pluto’s outermost known moon, orbits Pluto every 38 days at a distance of approximately 40,200 miles (64,700 km), while Nix orbits every 25 days at a distance of 30,260 miles (48,700 km).
Since their precise sizes were not known, New Horizon-obtained close-up pictures of both of them in July helped scientists to know more about these two moons.
Pluto’s two other small moons, Styx and Kerberos, are still smaller and too faint to be seen by New Horizons at its current range from Pluto but by July this year, they should come within the clearly visible distance.