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Smarties and the shape of the earth

oblate spheroid

oblate spheroid

The sphere is, according to Wikipedia, a reasonably correct model for earth. But mathematically the earth is  an oblate spheroid. An example of that would be smarties and M&Ms, spheres squished at the poles.

As a result of gravitation and the rotation of earth, it is about 21 km longer than the Earth’s polar radius. This is, of course, a tiny amount, but according to NASA, it is increasing at a surprising speed. Our little planet is becoming more oblate.


Why? Gravitational pull varies geographically, and are affected by a shift in mass, such as ice melting increases water in the oceans, tectonic shifts, and probably a lot more we do not understand. But it is changing. Water is on the move in a big way. This will have consequences for the rotation, and will affect the correction of time. This again affects space exploration and satellites. So you could say: climate change will alter time.

Chew on that.


gravitational map

Why do I bother with this ludicrously nitpicking geoscience? I am not a mathematician, astrophysicist, oceanographer, climate researcher. But ever since I discovered the problem of map projections as a child, I have scratched my head over this. I then assumed that I was too stupid to understand something that was surely simple. It is nice to know that it is incredibly complex. And that makes it endlessly fascinating.



“Incuriosity is the oddest and most foolish failing there is”. All-round nerd with a tendency to poke things with a stick to see what happens. Doodler, artist, bookbinder, photographer, illustrator, graphic designer, web developer.

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3 comments on “Smarties and the shape of the earth
  1. Very interesting! I wonder how extreme centrifugal force could become in this scenario, on a planetary scale? We all might just make it to space sooner than we thought… ;-)

    • It is indeed intriguing; sadly I am not really competent at reading scientific reports expanding on this, but it is well worth pondering!


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