Here's a breakdown:
* The Earth's rotation is not constant: It's influenced by various factors like:
* Gravitational interactions with the moon and sun.
* Mass redistribution on Earth (e.g., ice melt, tectonic shifts).
* Earthquakes and volcanic activity.
* Atomic clocks are incredibly precise: They are the most accurate timekeeping devices we have, allowing us to detect even tiny changes in the Earth's rotation.
* Slowing down is gradual: The Earth's rotation slows down by about 1.7 milliseconds per century. This means that a day is getting longer by about 1.7 milliseconds every 100 years.
* Leap seconds are introduced: To account for this slowing down, we sometimes add a leap second to our clocks. This keeps our clocks synchronized with the Earth's rotation.
So, while the change is very slow, it's measurable with atomic clocks and has been observed since we've had the ability to measure time with such precision.
