Earth Is Spinning Too Quickly - Clocks Aren’t Keeping Up - video Dailymotion

Live Science

Thanks to a speed-up of Earth's rotation, the length of the astronomical day and the length of the clock day aren't quite matching up. Eventually, international timekeepers may need to subtract a second.

Transcript

00:00The Earth's spin is speeding up.

00:03In 2020, the planet completed many of its revolutions around its axis, milliseconds

00:08quicker than on average.

00:10That's a problem for coordinated universal time, which uses ultra-accurate atomic clocks

00:16to meter out milliseconds, seconds, and minutes.

00:20The Earth's spin varies naturally due to the effects of the atmosphere, oceans, and

00:26core.

00:27As the atomic time and the length of the day determined by Earth's spin deviate by more

00:31than about 0.4 seconds, international timekeepers have to adjust the clocks.

00:38Until now, this has involved adding a leap second at the last minute of June or December,

00:43lengthening the day by the blink of an eye.

00:46That's because the overall trend in the Earth's rotation has been slowing.

00:51Until now.

00:53In 2020, Earth experienced its 28 fastest days since 1960.

00:59The quickest, July 19, saw the planet spin around 1.4602 milliseconds faster than its

01:07average 86,400 seconds.

01:12If the trend continues, international timekeepers may eventually need a negative leap second,

01:18subtracting a second from the end of the day rather than adding one.

01:23The decision would be made by the International Earth Rotation and Reference Systems Service

01:28in Paris, France.

Earth Is Spinning Too Quickly - Clocks Aren’t Keeping Up

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