Looking at a World map the other day it struck me that the vast majority of the global land mass is North of the equator. Any ideas why? Or is it just coincidence?
“There is no spoon.”
-The Matrix
Just coincidence. IIRC, the original supercontinent Pangaea was mostly in the southern hemisphere. When continental drift split them apart Gondawanaland moved north and Larusia drifted south.
Wait a few million years and the southern hemisphere may have most of the land mass.
“It turns out it isn’t so much a law of physics as it is a local ordinance.”
Do you remember hearing that the earth’s shape is roughly pear-like. In an physics class I rember that there are some second, third and fourth order distortions to the globe, I think because of its rotation. The pearshape is the second order distortion. Anyway, this makes the Northern Hemisphere and the South Pole “downhill” from the area of the southern Tropics. It is not much of a hill but when the tectonic engines aren’t pushing too hard, you might just find the continents “puddling” in the Northern Hemisphere and the S. Pole.
mipsman
The pear-shape of the earth is considered third-degree (imagine a cosine wave starting at the north pole and wrapping around to the south pole, and back–a pear would have three “periods”). There are six other third-degree shapes involved in approximating the shape of the earth, and most of them are larger than the pear-shape, but the pear-shape was the first to be measured because it is axially symmetric (measurements were made by early satellites as the earth rotated below, averaging out any variation along latitude.) Three of the five second-degree shapes are larger than any of the the third-degree shapes. The “low” and “high” spots (relative to what would be expected from a smoothly rotating fluid) have a rough correspondence with accumulation of continents: most lie in a band of lows that circles the earth through NA, SA, Antarctica, and Asia, but Africa sits on a high. There is another high in the Pacific, making that general pattern second-degree (like a prolate ellipsoid).
Don Anderson of Caltech did suggest that Pangaea had sat upon an ancient high, and the other continents have slid away from Africa. He won the Craaford Prize two years ago.
rocks
Not to mention that the ‘Equator’ is not a permanent thing: the poles shifting and all. 
What difference does it make? The continents are from 15 to 35 miles thick; the whole planet has a radius of about 4,000 miles; what does the earth’s crust have to do with it?
What’s wrong with wanting good looking maps? Geez. All the maps have the same projection: Mercator-Mercator-Mercator boring. And there’s SA all alone. Bottom light. How about a little feng shui (what?) and get a little bit better world?
Come on, people, work together.
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Thanks for the clarification RM. Isn’t there a name for those second,third … degree distortions, something like the Bessel Function. It has been a long time. What starts them distorting the perfect sphere, rotation? Even back in the 70’s, the idea of these low spots as an attractor for the continents was toyed with. I don’t remember who it was though.
Dougie_Monty, the crust is “floating” on the mantle. While most of the continents, movements are probably caused by mantle currents, if everything else is equal, the continents, purely under the effect of gravity, could find temporary stability at these low spots.
Jois, check back in 50 million years. If you don’t like the lay out of the continents, all you got to do is wait and it will change.
jois
I’ve seen more non-Mercator maps than Mercator over the last thirty years. I don’t think that’s what mipsman was referring to, when he said you’d have to wait 50 million, though.
mipsman
They are usually called spherical harmonics, the same functions that are used in describing electron orbitals.
The distortions of the earth’s shape is usually attributed to mantle convection–at least, at the level we’re talking about now. So, it’s kinda a chiken/egg thing. Would mantle convection tend to move the continents into low spots, which it has created? Right now, there is only a small correlation of plate tectonic movement with highs/lows of the earth’s gravity field. I’m pretty certain that that is an artifact of the way the data is analyzed. Abstract
rocks