JartexNetwork

Sup buddy?

From my pov, the sky is up.

But not only is up subjective, it is also an illusion.
Imagine this, you're floating in space, in the middle of nowhere.
There is no gravity pulling on you. You would be what physicists call an inertial observer. In that case, there is no way to tell which way is up or down or left or right without anything to compare your spatial position with.

For me here on Mars, up is the direction opposite to down, where down is the direction gravity exerts a force on me.
It is usually towards the core of the planet (usually, not always. For example because my cousin lives near Olympus Mons, the mountain itself has enough gravity to cause his house to tilt just a fraction of a degree away from the slope of the mountain so he feels normal).

I have also heard that your moon, Luna, exerts a force on earth too right? They cause the liquid ice (water in your words) on the surface to move around, this is also called tides, I think.

Also, by your moon, getting back to the question, not only is "what is up" subjective between two objects in different space but also between the same object in a different time. Next morning the sun will come up and it will be up in the sky for me.