The Earth is starting to spin faster - Photo: INKL
July 9 was a shorter day than usual, 1.3 milliseconds shorter than average, due to the Earth spinning faster on its axis. But there are days even shorter than July 9, and we're about to experience them: July 22 and August 5.
According to timeanddate.com, July 22 and August 5 will be 1.38 and 1.52 milliseconds shorter on average, respectively.
A day on Earth lasts about 86,400 seconds, or 24 hours, the time it takes our planet to rotate once on its axis. However, the speed of rotation depends on many factors, including the positions of the Sun and Moon and the Earth's gravitational field.
On these three days, the Moon will be farthest from the equator, changing the effect of gravity on the Earth's rotation.
Think of the Earth as a spinning top: if you put your finger in the middle and spin it, the top won't spin as fast as if you put your hand on top and spin it. The same thing happens to the Earth: when the Moon is near the poles, the Earth starts to spin faster, making the days shorter than usual.
LiveScience on July 10 contacted the International Earth Rotation and Reference Systems Service (IERS), the organization responsible for maintaining global reference standards and time frames, to confirm that we lost exactly 1.3 milliseconds on July 9.
Over the past few billion years, the Earth's rotation has actually slowed down, causing our days to lengthen. For example, in 2023, researchers discovered that about 1-2 billion years ago, a day on Earth lasted just 19 hours.
Scientists believe this is because the Moon is gradually drifting away from the Earth. This causes the Moon's gravitational pull on the Earth to weaken over time and causes the Earth to rotate more slowly on its axis.
However, since 2020, scientists have noticed that the Earth has begun to rotate slightly faster than at any point since 1970. According to timeanddate.com, the shortest day on record is July 5, 2024, which is 1.66 milliseconds shorter than average.
Source: https://tuoitre.vn/trai-dat-sap-trai-qua-hai-ngay-ngan-bat-thuong-20250711115537778.htm
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