There are many solar systems with planets of all numbers. Our solar system only has 8 planets.
There are different faces of the moon. There are 8 faces of the moon to be exact. They are the waning crescent, waning gibbous, full moon, new moon, first quarter, waxing gibbous, third quarter, and waning crescent.
the sun is a big star with a lot of gas. It is impossible for someone to live on the sun