In July 2020, the Earth rotated on its axis faster than ever before, so a day lasted exactly 1.4602 milliseconds shorter than 24 hours. A similar situation occurred at the end of last month, and a day again lasted less than 24 hours. On June 29, 2022, the Earth completed its orbit around itself rapidly and experienced the shortest day on Earth.
Explaining the reason for all this as the Earth is not perfectly spherical and can swing around its axis, scientists have now announced that the days on Earth are mysteriously lengthening. This affects not only our timekeeping but also many technologies. Let’s look at the reasons for this situation together.
A day rarely lasts 24 hours
While the clocks on our phones show that there are exactly 24 hours in a day, the actual time it takes for Earth to complete a single rotation can vary. These changes can even occur due to earthquakes and storms. In other words, according to the statement made by scientists, a day rarely lasts 24 hours. In fact, a few billion years ago, an Earth day was about 19 hours.
Over the past few years, the Earth’s rotation around its axis, the main factor determining how long a day will be, has been accelerating, resulting in a day becoming less than 24 hours. Despite this event that took place in the past days, this acceleration started to slow down suddenly. So the days are getting longer again and the reason for this is currently unknown.
Unprecedented in the last 50 years
Scientists have been able to make very precise predictions about the speed of Earth’s rotation since various techniques began to be developed to observe the Earth’s surroundings. A comparison between these predictions and an atomic clock has revealed information that a day has been getting shorter and shorter over the past few years.
But aside from the rotational velocity fluctuations that we know are caused by tides and seasonal effects, something surprising has emerged. Despite experiencing Earth’s shortest day on June 29, 2022, the long-term trajectory appears to have shifted from shortening to elongation since 2020. This change is unprecedented in the last 50 years, and the reason for this change is unclear.
Scientists have stated that this recent, mysterious change in the planet’s rotation speed may be related to a phenomenon called the “Chandler wobble.” Observations from radio telescopes also show that yaw has decreased in recent years; the two may be linked.
A final possibility that is considered plausible is that nothing particular has changed in or around the Earth. There can be long-term tidal effects that work in tandem with other periodic processes to produce a temporary change in the rate of Earth’s rotation.
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