If you feel the days get shorter as you get older, you might not even imagine it.
On June 29, 2022, the Earth made one complete revolution that took 1.59 milliseconds less than the average day length of 86,400 seconds, or 24 hours. While the 1.59ms shortening may not seem like much, it’s part of a larger, weird trend.
In fact, on July 26, 2022, there was another new record Approximately It was set when Earth ended its day 1.50 milliseconds shorter than usual, according to The Guardian and time-tracking website Time and Date. The time and date indicate that 2020 saw the most short number of days since scientists began using atomic clocks to take daily measurements in the 1960s. Scientists first began noticing this trend in 2016.
While the average day length may vary slightly in the short term, the day length has been increasing in the long term since the Earth-Moon system formed. This is because over time, the force of gravity has transferred energy from Earth – via tides – to the Moon, pushing it slightly away from us. Meanwhile, because the two bodies are in a tide-lock state—which means the Moon’s rotation rate and rotation are such that we only see one side of it—physics dictates that Earth’s day must be prolonged if the two objects are to remain in a tidal cycle. As the moon moves away. Billions of years ago, the Moon was much closer and the length of the Earth’s day is much shorter.
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While scientists do know that Earth days do shorten in the short term, a specific reason for why remains unclear — besides the impact it might have on how we track time as humans.
“Earth’s rotation rate is a complex business. It has to do with the exchange of angular momentum between Earth and the atmosphere, ocean influences and the effect of the moon,” Judah Levine, a physicist in the Time and Frequency Division of the National Institute of Standards and Technology, tells Discover magazine. “You can’t predict what will happen very far in the future.”
But Fred Watson, an Australian wandering astronomer, told ABC News in Australia that if nothing was done to stop it, “it will gradually go out of seasons with the calendar.”
“When you start to look at the real minute details, you realize that the Earth is not just a solid, spinning ball,” Watson said. “It’s got liquid on the inside, it gets liquid on the outside, and it has an atmosphere and all of this stuff spins a little bit.”
Matt King of the University of Tasmania described the trend to ABC News Australia as “certainly bizarre”.
“Obviously something has changed, and it has changed in a way we haven’t seen since the beginning of precision radio astronomy in the 1970s,” King said.
Could it be related to extreme weather patterns? As reported by The Guardian, NASA reports that Earth’s rotation can slow down strong winds in El Niño years and can slow the planet’s rotation. Similarly, melting ice caps move matter around the Earth, and thus can change the rate of rotation.
While this simple absorption of time has little effect on our daily lives, some scientists have called for the introduction of a negative “leap second,” which would subtract one second from the day to keep the world on track for the atomic time system, if the trend continues. Since 1972, leap seconds have been added every few years. The last one was added in 2016.
Physicist Peter Whibberley of the UK’s National Physics Laboratory told The Telegraph: “It is very likely that a negative second jump would be needed if the Earth’s rotation rate increased further, but it is too early to say whether that is likely to happen.” . “There are also international discussions going on about the future of leap seconds, and it is also possible that the need for a negative leap second may drive the decision toward ending leap seconds for good.”