Earth doesn't take 24 hours to complete a rotation!
Earth has been around for about 4.5 billion years now - that's 45 followed by eight zeros! Human beings, on other hand, have been around for a measly 2 million years. In these 2 million years, even though we have discovered a lot about our planet, there is still a lot left to be discovered.
1 - The speed of Earth's rotation is slowing down.
Indeed, Earth is no longer spinning as fast as it used to. Around 200 million years ago, when dinosaurs roamed on Earth, a day was only 23 hours long. Today Earth takes exactly 23 hours, 56 minutes, and 4 seconds to complete a rotation. This means that Earth is slowing down at the rate of 1.4 milliseconds every 100 years.
This is due to the gravitational pull of the moon. The moon's gravitational pull causes a tidal bulge, which is a slight distortion in the shape of Earth during tides. This affects the speed of Earth's rotation.
