(brief topic hijack to follow)
Hey Sad Emo,
To help yourself understand, do this mental exercise...I have found it to be liberating in trying to break away from forced physical conventions that I didn't even think about for most of my life.
First, picture the Earth hanging in space. Imagine it just like you always see it in pictures. Mostly in the U.S., it is presented to us from the perspective of North America in the upper left, and Africa in the lower right.
Now, expand your view point straight out from the Earth's equater to include the other bodies in our solar system as they are usually presented to us. In most pictures, the Sun is on the farthest left, then Mercury, Venus, Earth, Mars, and so on. Pull the image back farther in your mind until you can see the Sun and all of the planets. The reason that your initial mental picture will be similar to mine and to most people in the U.S. is simply because that is how we are taught to view the solar system. Even the putting the Sun on the left and the planets on the right is the way it is usually done. But why? As was mentioned, just because it has been done that way...convention. It is all from your chosen reference point though. Since there is no "up" or "down", or even "right" or "left" in space, we can have some fun with this exercise....
As I said, picture our entire solar system as you usually would (with the Sun on the left and the planets going off to the right). Close your eyes if it will help. Now, with Earth as the axis, slowly rotate the picture in your mind until the 4th-9th planets are on the left (upside down from "normal") and the Sun is on the right. At first, you will constantly have to keep forcing your mind to view the Earth "upside down". The Earth looks weird "upside down" doesn't it? But it isn't really upside down, it is just that your perspective has changed.
Now try rotating your mental picture around until you can zoom in and out of any point and fly to anywhere you want.
You'll never look at a globe the same way again.
I suppose that if people from the southern hemisphere had been the primary colonizers in the last few hundred years instead of the Europeans, our globes would have Australia "up" instead of "down".