Planets

What is a planet?
The International Astronomical Union (IAU) said that the definition of the planets are :-
a) In orbit around the Sun
b) Has sufficient mass for its self-gravity to overcome rigid body forces so that it assumes a hydrostatic equilibrium (nearly round) shape
c) Has cleared the neighborhood around its orbits
d) Has not cleared the neighborhood around its orbit
d) It's not a satellite

Then,At the same time, the new moons are also being discovered, both around existing planets and within these mysterious new worlds.

( Source : http://solarsystem.nasa.gov/planets/ )