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.


3 thoughts on “Smarties and the shape of the earth”

  • 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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