Question

Why planets and moon are non luminous?

Answer 1

Planets and moon or a natural satellite is non luminous because they do not emit their own light and they depend upon other luminous objects which that they appear..

Answer 2

Luminous objects are those which emit light on their own, i.e., they are a source of light.

Moon and planets are non luminous because they do not emit their own light. They reflect the light from the Sun

Hope this helps!