Why could Aug. 5 be shorter than 24 hours?
Tuesday is predicted to be one of the shortest days in the year, marking the latest time the Earth could see a day shortened by more than a millisecond.
Scientists predict that Aug. 5 will be 1.34 milliseconds shorter, according to the International Earth Rotation and Reference System Service and the U.S. Naval Observatory, published by TimeandDate.
The millisecond mark has been broken a handful of times this year, with the most recent being July 11, according to the data published by TimeandDate.
The predictions do not always come to pass, as July 22 had been predicted to be over a millisecond short, but the data revealed that only 0.87 milliseconds were shaved off, according to the Observatory's data.
Earth takes 24 hours to complete a full rotation in a standard day, equal to exactly 86,400 seconds.
Until 2020, the shortest day ever recorded by atomic clocks was 1.05 milliseconds short, meaning that Earth completed one daily rotation in 1.05 milliseconds less than the expected 86,400 seconds.
"Since then, however, Earth has managed to shatter this old record every year by around half a millisecond," astrophysicist Graham Jones wrote for TimeAndDate.
The shortest day recorded so far occurred July 5, 2024, when it came in 1.66 milliseconds short. The shortest day recorded this year was July 10, which came in 1.37 milliseconds short.
Why is this happening?
The Earth's rotation is influenced by the core and the atmosphere, according to Scientific American.
The science magazine says that the core's spin has been slowing, though for unknown reasons, meaning that the rest of the planet must speed up to compensate.
"The core is what changes how fast the Earth rotates on periods of 10 years to hundreds of years," Duncan Agnew, a geophysicist at the Scripps Institution of Oceanography, told the magazine. "The core has been slowing down for the last 50 years, and as a result, the Earth has been speeding up."
Atmospheric forces cause the rotation rate of the Earth to speed up in the summer of the Northern Hemisphere, according to Scientific American. Forces caused by the moon also affect the rate the Earth spins.
The magazine notes that on the geologic timescale, the Earth has been slowing, with the rotation taking half an hour less 70 million years ago.
Will the sped-up day be noticeable?
Of course, you're unlikely to notice such a minuscule difference in your standard 24-hour day.
But scientists who track and operate atomic clocks may be facing a bit of a predicament.
First introduced in the 1950s, atomic clocks replaced how scientists previously measured the length of a day by tracking the Earth's rotation and the position of the sun. The clocks are also capable of measuring in billionths of a second, or nanoseconds, which are synchronized globally to Coordinated Universal Time (UTC).
If the clocks are thrown off even a tiny amount, it could also throw off computers, servers, GPS signals, and other networks that rely on accurate times, David Gozzard, an experimental physicist at the University of Western Australia, told the Guardian.
This article originally appeared on USA TODAY: Aug. 5 might be a short day, see how much time could be trimmed off
Solve the daily Crossword
Hashtags
Try Our AI Features
Explore what Daily8 AI can do for you:
Comments
No comments yet...
Related Articles
CNN
2 hours ago
- CNN
How 300 resistors turned this sheet into a moving robot
Scientists created a flexible robotic sheet that can fold its shape, move across surfaces and grasp objects. CNN's Josh Campbell explains how.
Yahoo
3 hours ago
- Yahoo
Aug. 5 might be one of the shortest days of the year: Here's why
Scientists predict Aug. 5 just might be one of the shortest days of 2025. On Tuesday, Earth may rotate up to 1.25 milliseconds faster, according to an updated prediction shared on Multiple factors can contribute to changes in Earth's rotation rates, including atmospheric wind currents, the position of Earth's seas, and the position of the moon. Jason Nordhaus, an associate professor of physics at Rochester Institute of Technology in New York, says scientists have been tracking and collecting precise data since the 1960s and 70s that show the length of days has fluctuated over the decades. "It used to be that the Earth is actually spinning much slower, maybe like, three milliseconds slower per day," Nordhaus told ABC News. "Then, it's been steadily heading in the opposite direction, and then in the last maybe five years, it's really spun up. It's going faster, and so you're getting these shorter days." July 22 will be the second-shortest day of the year, scientists say Earth's rotational changes are imperceptible to the human eye, said Nordhaus. "This is nothing anyone would notice," the professor said. "If you wake up in the morning and you look out, you don't know what a millisecond is like." But the tiny changes can be picked up by the atomic clock, a precise tool scientists use for space navigation and for GPS systems, and the changes are more noticeable over time. "If you get it wrong and you're off by a millisecond or two milliseconds, I think that works out to be something like, you get your positions off by maybe 50 centimeters to maybe 100 centimeters. And so, then if you accumulate that over the course of a year, you might be off by half a kilometer in your GPS system," Nordhaus explained. Why July 9 was the shortest day on record Scientists use the idea of leap seconds to take the changes into consideration, similar to the concept of a leap year. "If you look back through the '70s to today, there's been something around … 25 or 30 leap seconds have been added to counter all this over time," said Nordhaus. This summer, there have been three other days – July 9, July 10 and July 22 – where Earth has appeared to rotate more quickly than usual. On July 9, Earth appeared to rotate 1.23 milliseconds faster, 1.36 milliseconds faster the following day and then about 1.34 milliseconds faster on July 22, according to Solve the daily Crossword
Yahoo
6 hours ago
- Yahoo
Why could Aug. 5 be shorter than 24 hours?
If you seem not to be able to get through the to-do list on Aug. 5, you'll at least have an excuse. Tuesday is predicted to be one of the shortest days in the year, marking the latest time the Earth could see a day shortened by more than a millisecond. Scientists predict that Aug. 5 will be 1.34 milliseconds shorter, according to the International Earth Rotation and Reference System Service and the U.S. Naval Observatory, published by TimeandDate. The millisecond mark has been broken a handful of times this year, with the most recent being July 11, according to the data published by TimeandDate. The predictions do not always come to pass, as July 22 had been predicted to be over a millisecond short, but the data revealed that only 0.87 milliseconds were shaved off, according to the Observatory's data. Earth takes 24 hours to complete a full rotation in a standard day, equal to exactly 86,400 seconds. Until 2020, the shortest day ever recorded by atomic clocks was 1.05 milliseconds short, meaning that Earth completed one daily rotation in 1.05 milliseconds less than the expected 86,400 seconds. "Since then, however, Earth has managed to shatter this old record every year by around half a millisecond," astrophysicist Graham Jones wrote for TimeAndDate. The shortest day recorded so far occurred July 5, 2024, when it came in 1.66 milliseconds short. The shortest day recorded this year was July 10, which came in 1.37 milliseconds short. Why is this happening? The Earth's rotation is influenced by the core and the atmosphere, according to Scientific American. The science magazine says that the core's spin has been slowing, though for unknown reasons, meaning that the rest of the planet must speed up to compensate. "The core is what changes how fast the Earth rotates on periods of 10 years to hundreds of years," Duncan Agnew, a geophysicist at the Scripps Institution of Oceanography, told the magazine. "The core has been slowing down for the last 50 years, and as a result, the Earth has been speeding up." Atmospheric forces cause the rotation rate of the Earth to speed up in the summer of the Northern Hemisphere, according to Scientific American. Forces caused by the moon also affect the rate the Earth spins. The magazine notes that on the geologic timescale, the Earth has been slowing, with the rotation taking half an hour less 70 million years ago. Will the sped-up day be noticeable? Of course, you're unlikely to notice such a minuscule difference in your standard 24-hour day. But scientists who track and operate atomic clocks may be facing a bit of a predicament. First introduced in the 1950s, atomic clocks replaced how scientists previously measured the length of a day by tracking the Earth's rotation and the position of the sun. The clocks are also capable of measuring in billionths of a second, or nanoseconds, which are synchronized globally to Coordinated Universal Time (UTC). If the clocks are thrown off even a tiny amount, it could also throw off computers, servers, GPS signals, and other networks that rely on accurate times, David Gozzard, an experimental physicist at the University of Western Australia, told the Guardian. This article originally appeared on USA TODAY: Aug. 5 might be a short day, see how much time could be trimmed off
