We say that a day is 24 hours, or 86,400 seconds, because that’s how long it takes for the Earth to turn once. But the Earth doesn’t turn in a perfectly even way. Most of the time, the Earth’s rotation is slowing down, so the average length of a day is getting longer by about 1.8 milliseconds per century. This means that a day was only 21 hours long 600 million years ago.
The length of the day changes because of a number of things, such as the Moon and Sun’s effects on tides, the way the Earth’s core and mantle are connected, and the way mass is spread out on the planet as a whole. The length of the day can also be changed by earthquakes, glaciers, the weather, the oceans, and the Earth’s magnetic field.
In 2020, scientists found something that shocked them. They found that the Earth’s spin has sped up instead of slowing down. It is turning faster now than at any time in the last 50 years. In fact, the 28 days that were the shortest on record all took place in 2020.
Scientists aren’t sure what’s causing the Earth’s rotation to speed up, but some have said it could be due to glaciers melting during the 20th century or a lot of water building up in reservoirs in the northern hemisphere. Experts say, though, that this speeding
The Earth’s speeding up is only temporary, and it will start to slow down again in the future.
But should we worry right now? Even though it won’t change how we live day-to-day, it could have serious effects on technology like GPS satellites, smartphones, computers, and communication networks, which all depend on very accurate timing systems. But these problems can be solved in the end, maybe by taking away a leap second instead of adding one.
So no, we shouldn’t be worried, unless the shorter days are caused by people.