Question Time!

[such_heights]

Calling my geologically inclined friends: please excuse a little lazy-webbing and help me resolve a debate with my father. Is there a non-arbritrary way of distinguishing a planet's north from its south, one that doesn't simply rely on convention? And if not, does that make all sci-fi talk of an unhabitated planet's southern hemisphere etc completely nonsensical?

... These are the things that keep me up at night.

Comments

[sophinisba]

Ooh, neat. From that first link,

Another common definition uses the right-hand rule to define an object's north pole: it is then the pole around which the object rotates counterclockwise.

It's only one of several conventions but seems like one that could be applied across the universe, so our sci-fi southern hemispheres are safe!

[silveronthetree]

Yes, I just realised that I hadn't actually answered the question!

[secondsilk]

I would use that definition: that counterclockwise around the northern pole one.

I lost marks on a science quiz once because I said the earth rotated West to East (which it does! (you just have to ignore place names that have east and west in them)), when the "correct" answer was supposedly counter-clockwise. Even though we were in Australia and closest pole is therefore the southern pole and clockwise rotation! I still hate that teacher.