Why are the moon and sun not planets?
Sun is a star.It produce heat and light by nuclear fusion i n its core.
Moon is satellite of Earth.It is orbiting earth Not a star.
Inter national astronomical union have defined planets in 2006.
1 planet must be orbiting a star
2 It should have enough mass to form spherical shape by gravity.
3 It must clear its neighborhood
So Moon and Sun does not come with in this definition..