Unbalanced worlds

Sometimes I look at the map of the world etched on to a paperweight on my table. It is designed to sit with the southern hemisphere on top. The shift in perspective forces me to think in different ways. One odd thought popped into my mind in the morning. Why does the world look unbalanced, with most of the continents clustered around the north pole? Mars, on the other hand has its biggest concentration of mass, the Tharsis plateau and the solar system’s highest mountain, near its equator.

Both planets have a liquid core over which the crust can move (see a good explainer here). A spinning globe of this kind should spin the heavy parts off towards the equator (although this is called polar wandering, the true pole remains fixed; it is the magnetic pole which moves). Mars makes sense, but the earth does not seem to. But some searching assured me that others have looked deeply into this problem before me. The mobile elements of the earth are not just the features we see on the crust, but the crust and the deeper mantle together. When you take everything into account, the earth seems to be in balance. The past positions of the continents show that the same principle held. When supercontinents form, they tend to be at the equator. Present day Africa is just such a remnant of the ancient supercontinent of Gondwanaland. (The video above plays out four possible futures of the earth’s continental movement; notice that most of them result in landmasses close to the equator.) It is a balanced world, but there is a lot going on below the surface.

By I. J. Khanewala

I travel on work. When that gets too tiring then I relax by travelling for holidays. The holidays are pretty hectic, so I need to unwind by getting back home. But that means work.

10 comments

  1. The breadth of your interests intriques me. I am interested in your posts but not sufficiently interested in all these subjects to do the research you do, and certainly not enough to post as often as you do. It is admirable.

    Liked by 1 person

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