If it feels like the days are getting shorter as you get older, you may not be imagining it.
On June 29, 2022, Earth made a full rotation that took 86,400 seconds, or 1.59 milliseconds less than 24 hours, than the average day length. While a 1.59 millisecond shortening doesn’t seem like much, it’s part of a larger and weirder trend.
As a matter of fact, a new record was broken on July 26, 2022. almost It is determined when the Earth finishes its day 1.50 milliseconds shorter than normal, as reported by Guard and time tracking website Time and Date. Time and Date notes that 2020 has the shortest number of days since scientists began using atomic clocks to make daily measurements in the 1960s. Scientists first started noticing this trend in 2016.
While the length of an average day may vary slightly in the short term, in the long term the day length has been increasing since the formation of the Earth-Moon system. This is because, over time, the gravitational force carries energy from the Earth – via the tides – to the Moon and pushes it slightly further away from us. Meanwhile, since the two bodies are in tidal lock—that is, the Moon’s rate of rotation and revolution are equivalent in such a way that we can only see one of their sides—physics dictates that Earth’s day must be lengthened for the two bodies to remain in tidal lock. as the moon moves away. Billions of years ago, the Moon was much closer and the length of Earth’s day was much shorter.
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While scientists do know that Earth’s days are getting shorter on a short-term scale, one sure-fire reason why it remains unclear – and it may have an impact on how we as humans track time.
Judah Levine, a physicist in the time and frequency department, said, “Earth’s rate of rotation is a complex task. It has to do with the angular momentum exchange between the Earth and the atmosphere and the effects of the ocean and the effect of the moon.” National Institute of Standards and Technology, told Discover Magazine. “You can’t predict what’s going to happen very far in the future.”
But Australian astronomer Fred Watson He told ABC News in Australia if nothing is done to stop it, you will “slowly remove the seasons from the calendar.”
“Once you start looking at its true essence, you realize that the Earth is not just a solid spinning ball,” Watson said. “There’s liquid inside, there’s liquid outside, and it has an atmosphere and it all shakes a little bit.”
Matt King of the University of Tasmania called ABC News Australia’s trend “absolutely bizarre”.
“Obviously, something has changed and changed in a way we haven’t seen since the dawn of definitive radio astronomy in the 1970s,” King said.
Could it be related to extreme weather conditions? as reported by GuardNASA reports Earth’s rotation could slow stronger winds During the El Niño years and slowing down the planet’s rotation. Similarly, melting glaciers moves matter around the Earth and can thus change its rotational speed.
While this little time sucking has little effect on our daily lives, some scientists have called for the introduction of a negative “leap second” that would subtract one second from a day if it were to keep the world on the right track for the atomic time system. the trend continues. Since 1972, leap seconds have been added every few years. The last one was added in 2016.
“It’s quite possible that a negative leap second will be needed if the Earth’s spin rate increases further, but it’s too early to say whether that will happen,” said physicist Peter Whibberley from the UK’s National Physical Laboratory. Telegram. “There are also international debates about the future of leap seconds, and the need for a negative leap second can push the decision to end leap seconds forever.”
