Tuesday, September 15, 2015

Not a Sphere

This is not so much a fact I never knew as a fact I never thought about. But it's really neat.

The earth is not round (spherical), or anywhere near it. Yeah, the earth with its oceans is close... but the land/solid part of our planet is not.

Now I'm going to bask in the coolness of knowing this fact and having such a nice illustration of it.


It's hard to tell what the original source of this image is.... I got it from the Twitter account of 9GAG, which is notorious for taking images without crediting the original. It looks like it may be a color shifted version of this, which came from this, but I'm not sure. 


Update: Well, it sounds like this graphic doesn't show the shape of the Earth beneath the oceans -- it's actually a map of its gravity or something like that. Ooops... I am clearly (mis)informed. Quoting the story that corrects the error:

The reason Earth appears lumpier is because it does not have a uniform mass — which is one of the key elements in measuring gravity. If you could sample different sections of Earth's mantle, you would get different materials of varying densities.

As a result, the denser parts of the mantle exert a stronger gravitational force on the water above compared to the less-dense regions. So where gravity is strong, you see low dips..., and where gravity is weaker, you see high [peaks].

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