9. Earth’s Rotation
In kindergarten, you learned that there are 24 hours in every day. If you really think about it, though, it is kind of unbelievable that every single day is exactly 24 hours, not one second more or one second less. However, Earth’s rotation slows down every century, which means that our days are not precisely 24 hours each. NASA has reported that the Earth’s rotation actually takes 24 hours and 2.5 milliseconds.
Although 2.5 milliseconds may not seem like a big deal, Earth has been around for billions of years. If Earth’s rotation slows down every century, that time can really add up. For example, when the dinosaurs were around, days were only 23 hours long. If you thought each day goes by too fast now, just imagine what it would have been like a billion years ago.