Jan 8th: Earth Rotation Day

Today is Earth Rotation Day and today’s word of the day is centrifugal force. 

Centrifugal means ‘moving or tending to move away from the centre’. Centrifugal force happens only in rotating objects.

If the Earth didn’t rotate, we would have no centrifugal force.

Ok, cool?

No, not really.

This would mean that all the water would heap together at the poles, creating a huge megacontinent around the Equator. All of Russia and Canada and the majority of Europe would be underwater.

The Earth if it didn’t spin. http://www.esri.com/news/arcuser/0610/nospin.html

Why, if centrifugal means moving away from the centre?

The world has been spinning for a few years already (a few billion, to be precise), and due to this it is not a perfect circle, but more like a flattened sphere, with more bulk around the Equator. A bit like a nice little belt around its middle. This means that gravity is strongest at the Poles, as there’s less bulk around there.

According to my source, the distance is an extra 21.4km longer from average sea level on the Equator to the centre of the Earth than from average sea level on a Pole to the centre of the Earth. Hence why the oceans would migrate to the Poles. A bit like penguins.

The green parts experience more gravity. http://www.esri.com/news/arcuser/0610/nospin.html

Interesting additional fact: And if the Earth didn’t rotate, a day would last as long as a year.

Celebrate with me by reading more here. (Superduper fascinating, though I had to read it with a dictionary and a very excercise-hungry brain!)

Or if you’ve had enough brain exercise for the day, just enjoy the fact the Earth rotates.

The parental globe

Happy Earth Rotation Day! 

4 Replies to “Jan 8th: Earth Rotation Day”

  1. If there’s more gravity at the poles, am I lighter when I’m at the equator and heavier when I’m at a pole?

    1. Yes, 28.3 grams less.
      (True story, I googled it.)

  2. Mahtavaa asiaa. Vielä täytyy sulatella. 🙂

    1. Kannattaa sulatella Oatly suklaamaidon kanssa OMNOMNOM.

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