How did we “calibrate” the second?

1.01K viewsOtherPlanetary Science

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

18 Answers

Anonymous 0 Comments

The second was initially defined to be a specific fraction of a day. When we got better and better mechanical ways of measuring seconds, we just built that in. More recently, it became more important to have the second have a constant definition, rather than tied to earth’s rotation rate. But it’s still really close.

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