You've always known a minute has 60 seconds, but sometimes, precisely at midnight on certain dates, the world's most accurate clocks are quietly adjusted to make one minute last 61 seconds. What cosmic wobble or earthly shift makes this strange "leap second" necessary?

Question

AhaDaily · Accepted Answer

To synchronize with the Earth's slightly unpredictable rotation rate Who knew a minute could sometimes have 61 seconds? Turns out, our planet's spin isn't perfectly constant. Atomic clocks are super stable, but Earth's rotation fluctuates. To keep our measured time in sync with astronomical time, scientists occasionally add a "leap second." Aha! You heard right! This seemingly sci-fi "leap second" system is a real thing, managed by the International Earth Rotation and Reference Systems Service (IERS). According to the UK's National Physical Laboratory (NPL), since its introduction on January 1, 1972, a total of 27 leap seconds have been added globally. What's mind-blowing is that Earth's rotation is actually slowing down over the long term, largely due to lunar tidal forces. But in the short term, factors like winds, ocean currents, and even earthquakes can cause unpredictable fluctuations. So, these "extra seconds" are critical to prevent our incredibly precise atomic clock time from drifting too far from the Earth's actual angular position, which could mess up navigation, communication, and satellite systems. Seriously, hats off to the silent guardians of time who keep our world from descending into chronological chaos!

You've always known a minute has 60 seconds, but sometimes, precisely at midnight on certain dates, the world's most accurate clocks are quietly adjusted to make one minute last 61 seconds. What cosmic wobble or earthly shift makes this strange "leap second" necessary?

Want one of these every day?