The Earth Spun Faster in 2020, So Scientists Had to Adjust Time
The year 2020 was such a crazy year, even time did not escape its menace. The world's official timekeepers at International Earth Rotation and Reference Systems Service (IERS) determined the Earth itself was in a hurry to get over 2020, as their highly accurate atomic clocks detected 2020 had the shortest days on record.
International time is largely based on the Earth's rotation, which is quite accurate: It almost always takes 86,400 seconds to rotate on its axis. But it is not perfect. Minor deviations have been recorded ever since atomic clocks were invented in the 1960s, according to Time and Date. These deviations are largely caused by variations in the Earth's atmospheric pressure and activity inside the Earth's core.
Earth Spinning Faster in 2020
In the past years, scientists have had to add milliseconds from the Coordinated Universal Time (UTC) because the Earth had been rotating slower. Until 2020 came. Atomic clocks around the world detected the Earth was spinning faster.
For the first time in almost 50 years, the Earth seemed to be in a hurry to get the days over.
"Before this year began, the shortest day since 1973 was July 5, 2005, when the Earth's rotation took 1.0516 milliseconds less than 86,400 seconds. But in the middle of 2020, the Earth beat that record no less than 28 times," reported Time and Date.
In 2020, the Earth completed its rotation in 1.4602 milliseconds less than 86,400 seconds, such that the IERS had to add the missing time to the world's international time or UTC. It is called a positive leap second, which they hadn't encountered in decades. They had always been subtracting a negative leap second to the UTC prior to 2020.
Today, there are over 200 atomic clocks installed around the world, all of which are synchronized to maintain a very precise time scale called International Atomic Time or TAI. The IERS regularly compares TAI with UTC to make sure our clocks—from your smartwatch to your smartphone—are up to speed.