Bad Astron­omy com­piles a list of ten things you don’t know about the Earth. You prob­a­bly (hope­fully?) know a few of these already.

  1. The Earth is smoother than a bil­liard ball
  2. The Earth is an oblate spher­oid
  3. The Earth isn’t an oblate spheroid
  4. The Earth is not exactly aligned with its geoid
  5. Jump­ing into a hole through the Earth is like orbit­ing it
  6. The Earth’s inte­rior is hot due to impacts, shrink­age, sink­age, and radioac­tive decay
  7. The Earth has at least five nat­ural moons; but not really
  8. The Earth is get­ting more massive
  9. Mt. Ever­est isn’t the biggest mountain
  10. Destroy­ing the Earth is hard

Amaz­ingly I did know about the blog­gers’ favourite, num­ber 5, thanks to an uploaded clip from an old His­tory Chan­nel pro­gramme on grav­ity. So there.

via Kot­tke