It's a common truism that there are only 24 hours in a day, but, according to precise measurements, that isn't exactly true.
The Earth typically takes 86,400 seconds, or 24 hours, to spin on its axis, TimeandDate.com explained. But the invention of precise atomic clocks in the 1960s showed that the length of the Earth's daily rotation could actually vary by a matter of milliseconds. Until recently, the Earth's rotation was slightly longer than 24 hours. But in 2020, the Earth started speeding up. "It is certainly correct that the Earth is spinning faster now than at any time in the last 50 years," Peter Whibberley, National Physical Laboratory time and frequency group senior research scientist, told The Telegraph on Monday. Before 2020, the record for the shortest day was set on July 5, 2005, which clocked in at 1.0516 milliseconds less than 86,400 seconds, The Weather Channel reported. In 2020, that record was broken a total of 28 times. The fastest day since record keeping began happened on July 19, 2019, and clocked in 1.4602 milliseconds shorter than average. Scientists predict that days in 2021 will be even faster. They estimate that days are now 0.05 milliseconds shorter on average, which will leave 2021 running 19 milliseconds behind. But why does a difference of milliseconds matter? At stake is the syncing of solar time with Earth's atomic clocks, because satellites and other communication devices are usually based on the position of the sun and stars.