Ever wish you had more hours in the day?
Compared to your ancestors, you do. Earth’s rotation is slowing down, so a modern day is about 1.7 milliseconds longer than a day a century ago.
I know that doesn’t sound like much, but when dinosaurs lived, a year was about 370 days long. Give it another hundred million years, and an Earth year may only be 360 days long.
I’m bringing this up because today is leap day. It might seem like we have a handle on counting time. As long as we add an extra day every four years (but not on century years that aren’t divisible by 400), we’ll never be late.
The truth is, our calendar has to be tweaked often to match the seasons and our trip around the sun. There will never be a time when the calendar is set in stone.
Lucky for humans, this constant change happens so slowly that we can’t tell. But for those who work with super-accurate clocks, leap minutes and leap seconds are as important as leap days.