The Earth doesn’t rotate uniformly. The Earth’s rotation slows over time, increasing the length of the day by 1.8 milliseconds on average every century. This means that 600 million years ago, a day only lasted 21 hours. The tidal effects of the Moon and Sun, core-mantle coupling within the Earth, and the planet’s total mass distribution all contribute to the changes in day duration.

In 2020, scientists made a surprising discovery. They discovered that the Earth’s rotation has accelerated rather than slowed. It is now spinning at a quicker rate than it was 50 years ago. The 28 days with the shortest duration on record occurred the same year. Scientists are still unsure what is causing the increase in Earth’s rotation rate, while some suggest that it could be linked to the melting of glaciers in the twentieth century or the massive storage of water in northern hemisphere reserves.

Should we be concerned for the time being? Although it will have little effect on our daily lives, it could have major consequences for technology such as Global Positioning System (GPS) satellites, smartphones, computers, and communication networks, all of which rely on extremely precise timing systems. However, such concerns can be resolved in the end, possibly by simply eliminating rather than adding a leap second. We shouldn’t be concerned unless the shortening of the day is caused by human activities.