Moon of Pluto
Hydra
Hydra is a moon. It orbits Pluto. It is about 40 km across – about as wide as Switzerland. Hydra is Pluto's outermost moon (around 51 x 36 x 32 km).
Fact file
- Type
- Moon of Pluto
- Diameter
- 40 km
- Distance from Pluto
- 64,738 km
- Orbital period
- 38.2 days
- Temperature
- -229 °C on average
Hydra orbits Pluto.
Interesting facts about Hydra
- Hydra is Pluto's outermost moon (around 51 x 36 x 32 km).
- Its surface is almost pure water ice and reflects a lot of light.
- Hydra spins once on its axis in only about 10 hours – and tumbles as it does so.
Frequently asked questions about Hydra
How big is Hydra?
Hydra has a diameter of 40 km. That is about 1.2% of the diameter of our Moon.
How far is Hydra from Pluto?
Hydra orbits Pluto at an average distance of 64,738 km.
How long does Hydra take to orbit Pluto?
Hydra orbits Pluto once every 38.2 days.
How cold or warm is it on Hydra?
On Hydra the average temperature is −229 °C.
Formation
Like Pluto's other small moons, probably made of debris from the Charon impact.
Atmosphere
No atmosphere.
Exploration
Discovered in 2005 with the Hubble telescope, photographed in 2015 by New Horizons.
Compared with Earth
Named after the nine-headed water serpent of Greek myth.
Other moons of Pluto
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