To be formally announced tomorrow so I hear.

Pluto, Charon, Nyx and Hydra

Nyx and Hydra join Pluto and Charon. Interesting choice of names, Pluto being named after the god of the Underworld. Nyx is the goddess of night (the Sun is very faint all the way over there) so that's a good one. Hydra was the offspring of Styx and Styx was the river that Charon ferried across dead souls to the Underworld.

With a bit of Pluto talk probably coming up in the next few days the issue of its planetary status will no doubt crop up. The International Astronomical Union have it on the table for the 26th General Assembly held in Prague in August this year. Hopefully the word planet will have some precise definition to it.

In my opinion the only logical thing to do is to come up with a definition that removes Pluto from planetary status. In the next few years we could well find dozens of objects similar to Pluto beyond Neptune. Even astronomers will have a hard job remembering all the planets in the system, let alone the general public.

Pluto should not keep planetary status for historical reasons alone.