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Earth's rotation record - The Earth is accelerating - Wikipedia

Earth’s rotation record – The Earth is accelerating – Wikipedia


The Earth is suddenly spinning a little faster. No need to worry unless you are a programmer.

A day consists of 24 hours, or more precisely 86,400 seconds. This is the time it takes for the Earth to rotate on its axis. But the Earth doesn’t always rotate at the same speed — and as a result, the days get a little longer.

Why doesn’t the Earth always rotate at the same speed

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Due to the fact that all possible masses move in the Earth, the rotation always changes slightly. Above all, water in the oceans and air in the atmosphere play a role: sometimes a glacier melts away, sometimes there is a particularly high pressure area – and the moon is always slowing down a bit because of the tidal forces that cause water on Earth to push back and forth. As a result, the days on Earth get a little longer.

Since 2020, measurements have shown that the Earth is spinning faster again in a few days. The fastest day was last measured due to high-resolution time measurements on July 29, 2022. That day was 1.59 milliseconds shorter, so midnight came 0.00159 seconds faster.

Science baffles the reasons. “There are different assumptions,” says geodesist Daniela Thaler of the Federal Agency for Cartography and Geodesy in Germany. “For example, slowing ocean movement due to changes in the Gulf Stream or the melting of ice caps.”


Earth as a snowboarder

If it raises its arms up – that is, near the axis of rotation – it accelerates. Similarly, the Earth slows down as the polar peaks melt and water flows away from the poles.


This is worrying for the research community mostly because of the computer systems (the box). “Otherwise, no one would notice, there is even research that says millions of years ago, days were only 21 hours,” says Daniela Thaler.

leap second problem

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We measure time in atomic hours, i.e. the hours in which atoms oscillate – always at the same speed. The atoms are not slowing down, but the Earth’s rotation is slowing down. To ensure that atomic time and solar time do not diverge, a correction is required every few years: a leap second is inserted. That extra second can kick computers out of sync.

Websites have been disrupted by leap seconds, satellites have become nearly unnavigable and once banned airline computers. In the meantime, the systems have learned to deal with this second positive step. However, if a negative sign is suddenly introduced into the future – that is, a second removal of the insertion of atomic clock days into the shorter cycle of Earth’s rotation – it could create new problems.