Question

where is earth up in the solar system or down?

Answer 1

The solar system and the galaxy each have an axis of spin, just as the earth does. You can define one pole of those axes as "up" if you like, for convenience, but there's ...

Answer 2

When you are on Earth, up allways points to space, and down allways points to the center of the planet. Gravity decides what side is up.In space, things are different. When you refer to “sides” of the planet, you will refer to “north hemisphere”or “south hemisphere”. The “up side” has no meaning.