source: How long is a day?⌚ | How long is a day?⌚ | By StarTalk | Facebook
What
- What moves mass further from the the poles and closer to the equator slows Earth down.
- Vice versa, what moves mass further from the equator and closer to the poles speeds Earth up.
Such as
- Sloshing tides.
- If there is an earthquake and one of the continental shifts north ⇒ mass on earth surface moves further from the equator and closer to the north pole ⇒ speeding up the rotation of the Earth
- Large animal migration changes mass of the earth from north to south and further away from the rotation of the axis ⇒ speed Earth up
- Land glaciers in Antarctica melting ⇒ ice near the pole melts and water flows closer to the equator ⇒ slow down the rotation of the Earth.
- Anything that remaps the surface of the Earth: volcanoes, etc.
Hence
- In principle, Earth can speed up or slow down depends on what’s going on.
- All factor combines, Earth day has been increasing.