As Lister Sinclair pointed out in the CBC program “Ideas” in July 1996, East and West are fundamentally different from North and South on the Earth’s surface, although they look identical on.a small flat map. When you go North on the globe, you eventually start going South when you loop over the Pole; the same happens in reverse when you go South – you start going North eventually. But you can continue going West, round and round, forever; and likewise when going East.
This has to do partly with the properties of a spherical surface, and partly with the way we draw lines on it meridians for the North-South direction, and parallels for the East-West direction. The reason why we draw these lines of longitude (meridians) and latitude (parallels) differently is because the Earth rotates (spins) on a North-South axis, with its imaginary ends emerging at the Poles.
The meridians are all great circles (a term in spherical geometry). Great circles are circles drawn on a spherical surface such that their centres coincide with the centre of the sphere; these are the biggest circles that can be drawn on a spherical surface. On the other hand, among the parallels only the equator is a great circle; the other parallels are all lesser circles, getting smaller and smaller as we approach the Poles, where they shrink to a point (dimension zero). The meridians measure longitude and daily time zones, the parallels measure latitude and main climates, from tropical to moderate to Arctic/Antarctic. Thus longitude is linked to the daily rotation of the Earth about its axis, and latitude is linked to the annual seasons, i.e. the Earth’s revolution around the Sun.
On a sphere, the meridians converge at the Poles, while the parallels never converge. “Of course”, you say, “parallel lines never meet”, whether they are straight lines or circles. But wait: imagine two roads in tropical or moderate latitudes going straight North: are they parallel or not? They surely seem so, in the short range, but truly they are not, because in the long range they converge at the Pole. “Parallel” on a spherical surface has a different meaning than on a plane. Meridian roads would seem parallel for a long long time, and yet they finally converge quickly at the end.
Longitude, latitude, and altitude (the height of mountains above sea level and the depth of ocean trenches below sea level) are the three dimensions that pinpoint any location on the Earth’s surface. They can be compared to the three dimensions of the U.N. voting behaviour o’ nations during the Cold War (1946-1989). East-West differences (politically) are like longitude, and they have almost converged in our unipolar system with one remaining superpower. North-South political/economic differences are like latitude, and they have not converged at all. Supranational tendencies are like altitude (“lofty aspirations” and “deep longings”). Altitude measured in length units is rather insignicant in size when compared to the other Earth dimensions; even Mount Everest is just a pimple on the globe, and even the Marianas trench is only a dimple. Likewise, supranational voting is (was) also relatively insignificant in comparison to the major political divisions.
Last night I watched a beautiful sunset at Sauble Beach on Lake Huron, where the sun sets over the water. For the first time, I had an impression, not of the disk of the Sun dipping below the horizon, but of the Earth spinning to hide the Sun, swinging our location to the night side, in a regularly repeated circadian eclipse. What had been superficial intellectual knowledge became a.brand-new cognitive experience. I have finally internalized what I had thought I knew.