It seems like everything with our calendar is based around 24hr days and the number of 24hr days to revolve around the sun. But a 24hr day can be broken down to 1,440 minutes and in turn 86,400 seconds. How did we (humans) calibrate the second so that exactly 86,400 would be 1 rotation of the earth to the point where we never need something like a “leap second” like we have with leap years?
In: Planetary Science
Imagine you have a tiny clock inside a cesium atom. This clock doesn’t have hands that move around like the clock on your wall. Instead, it “ticks” in a special way. Inside the cesium atom, there’s a tiny part called an electron, which can jump back and forth between two spots. Each time it jumps, it’s like a tick of our tiny atomic clock.
Scientists have found out that if you watch a cesium atom, the electron will jump back and forth exactly 9,192,631,770 times in one second. Because this number is always the same, it helps everyone in the world agree on what a second is.
To get the second from the cesium atom, scientists use a special tool called an atomic clock. This clock watches the cesium atom very closely. It counts how many times the electron jump.
So, thanks to the cesium atom’s steady ticking, we know exactly how long a second is, and we can keep time very precisely for all sorts of important things, like computers, GPS, and even when we launch rockets into space!
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