Hubble discovers Plutos 4th moon

[LunaSea]

P4 is the smallest moon yet found around Pluto, with an estimated diameter of 8 to 21 miles (13 to 34 km). By comparison, Pluto's largest moon Charon is 648 miles (1,043 km) across. Nix and Hydra are roughly 20 to 70 miles (32 to 113 km) wide.

The new moon lies between the orbits of Nix and Hydra, two satellites discovered by Hubble in 2005. It completes an orbit around Pluto roughly every 31 days.

The moon was first seen in a photo taken with Hubble's Wide Field Camera 3 on June 28, 2011. The sighting was confirmed in follow-up Hubble observations taken July 3 and July 18.

http://hubblesite.org/newscenter/archive/releases/2011/23/

[Ian David]

1. They should name the moon either Colbert or Xenu. n/t

[eppur_se_muova]

2. Too late to rec.

I hadn't even heard there was a second or third moon!

If Pluto's not a planet, what's it doing with so many moons? :crazy:

[Humanist_Activist]

3. I would assume many TNOs would have one or more moons...

All you need is enough mass to be able to capture objects that get near the celestial body without them crashing into it. There are even asteroids(not dwarf Planets like Pluto or Ceres) that have moons, and others that are locked into orbits around barycenters due to close to equal mass, for lack of a better word, these orbit each other. Actually, technically, Pluto's moons don't orbit it but a common center of gravity(barycenter) between Pluto and Charon, which happens to be above Pluto's surface.

[laconicsax]

4. Last I read, over 60 Trans-Neptunian objects have moons. n/t