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

[lefaym]

I think it's got something to do with the flow of electrons. You create a magnet (and the entire planet is a huge magnet) by making all (or most) of its electrons flow in the same direction, so I'm guessing it's something to do with that.

It can't be completely arbitrary, because the Earth's poles actually reverse every million years or so, which means all the compassess will point in the opposite direction.

However, the convention of representing the North as the "top" and the South as the "bottom" of the map is completely aribitrary.

[kel_reiley]

However, the convention of representing the North as the "top" and the South as the "bottom" of the map is completely aribitrary.

^this, this is what i meant :)

[zahrawithaz.livejournal.com]

It's also relatively recent and culturally specific. Maps drawn in Europe in the Middle Ages (usually called T-and-O maps, because they look like T inside a giant O) can point in any direction, but most often put East at the top--where the draftsmen thought Paradise was located--which meant that Europe was crammed into the lower left-hand corner.

[kel_reiley]

that makes sense