Latest news with #InternationalEarthRotation
Yahoo
6 days ago
- Science
- Yahoo
Earth's Rotation Is Speeding up this Summer. Here's Why
The moon shapes Earthly days Credit - Getty Images If you're the kind of person who gets a lot done, you're grateful for every one of the 86,400 seconds that make up a day. On July 9, however, as well as on July 22, and August 5, you won't get your full complement of seconds. On these days the Earth will be measurably—and, so far, unaccountably— accelerating its rotation, shaving from 1.3 to 1.5 milliseconds off of the usual 24 hours the typical day gets. A millisecond, or one thousandth of a second, is admittedly not much—an eyeblink takes about 100 milliseconds. But with atomic clocks tracking the Earth's rotational speed so closely that once every year and a half or so, the International Earth Rotation and Reference Systems Service (yes, there is such a thing) has to add a leap second to the year to account for any increase in the planet's speed, every millisecond counts. So what's behind the sudden speed-up and what effect could it have? Around the world, there are 450 atomic clocks in operation, tracking the time with an accuracy that sees them gaining or losing only about 1 second every 100 million years. The clocks exist for more than just tidy temporal bookkeeping. Everything from weather satellites to GPS satellites to telecommunications to nuclear missiles and other weapons of war rely on precise timing to operate properly. So when both astronomers and the operators of the clocks notice that the atomic ticks are falling out of step with the rotation of the Earth, people take notice. The shortest day ever recorded since atomic clocks went into operation in the 1950s occurred last year, on July 5, according to Date and Time, when the Earth shaved off 1.66 milliseconds. Three years earlier, on June 30, 2022, things moved similarly quickly, when the day came in 1.59 milliseconds under the 24-hour wire. But with three short days predicted over the next few weeks by astronomers and clock watchers, this summer is something even more rare. There are a number of reasons the Earth may be changing its speed this way. But it's not clear yet just which explanation is responsible this time. The likeliest cause is the position of the moon. Lunar distance is an always-changing thing, with the moon tracing an elliptical orbit around the Earth. At its closest approach—or perigee—the moon is only 224,000 miles distant. At its furthest—or apogee—that gap widens to 251,655 miles. On the three speedy days this summer, the moon will be at or near apogee—which is a puzzle, since lunar gravity is such that the Earth tends to slow down, not speed up, when the moon is farther away. The moon's orbit is not only elliptical, however, but cockeyed too, angled anywhere from 18° to 28° relative to the Earth's equator. The sharper that angle is the faster the Earth orbits, with lunar gravity in this case speeding things up, countering the braking effect that lunar apogee usually applies. On the three days in question this summer, the moon will be close to its 28° peak. The moon is not the only thing that can shorten earthly days. Earthquakes can too, redistributing subterranean mass and causing the planet to accelerate or slow down in the same way a figure skater can change the speed of her spin when she tucks in or extends her arms. In 2005, an earthquake in Indonesia shifted the Earth's polar mass about one inch toward the east, decreasing the length of a day by 2.68 microseconds—or millionths of a second. No significant earthquake has occurred recently, however, ruling temblors out as the cause of the current speed up. Climate change—again and seemingly always—may play a role too. Last year, two NASA-funded studies found that since 2000, melting glaciers have caused the axis of the planet—or the centerpoint of its spin—to shift by about 30 ft., changing the speed of rotation. The catch is, in this case the change causes the planet to decelerate, not speed up—by about 1.33 milliseconds per century. If warming continues at its present pace, it is projected to increase the length of our days by 2.62 milliseconds by the end of the century. Other factors, including rising ocean levels and the warming—and thus swelling—of the atmosphere can make a difference too, slightly increasing planetary circumference. Even the springtime blossoming of trees can play a role. 'In northern summer, the trees get leaves,' geophysicist Richard Holme of the University of Liverpool told Live Science. 'This means that mass is moved from the ground to above the ground—further away from the Earth's spin axis.' In all of these cases too, however, the effect is to slow the Earth, not speed it up. So that brings scientists back to lunar gravity as the cause of the current acceleration—and that's a reason not to fret the slightly shorter days. The Earth and the moon have been doing their dance for the better part of 4.5 billion years, and it's always been a stable one. Here's betting they've got a few billion more years yet in their run. Write to Jeffrey Kluger at
Yahoo
6 days ago
- Science
- Yahoo
Why July 9 Is Likely the Shortest Day in Recorded History
Scientists are predicting that July 9, 2025, will be one of the shortest days in recorded history July 22 and Aug. 5 are also predicted to clock in slightly shorter than average Scientists are not totally able to explain the phenomenon, but have proposed adding a "leap second" to the day as soon as 2029Everyone has the same 24 hours to get things done in a day. However, they're going to have a little less time on Wednesday, July 9. That's because the day will be going on record as one of the shortest in history, according to scientists. The 24-hour length of a day is based on the amount of time it takes Earth to complete one rotation on its axis. Twenty-four hours translates to approximately 86,400 seconds. On July 9, experts suggested that the day might be approximately 1.3 milliseconds shorter than average, according to TimeAndDate. Citing the International Earth Rotation and Reference Systems Service, The Tab reported that people might even have 1.6 milliseconds less in their day. A similar trend is expected to occur with infinitesimally small days on July 22 and August 5. While it's unclear exactly what is happening to speed up Earth's rotation, the outlets noted that this has been a recurring trend since 2020. There have been several days that have clocked in at roughly a millisecond shorter than normal. July 5, 2024, currently holds the record for the shortest day, clocking in 1.66 milliseconds short of the average. One theory is that Earth's distance from the moon will impact the length of a rotation, according to Popular Mechanics. Research has also suggested that humanity has changed the length of a day. According to USA Today, a study conducted by NASA suggested that "dwindling ice and groundwater and rising seas" was leading to days that are 1.33 milliseconds longer. What does it mean that July 9 will be shorter than average? For most people, nothing. Even 1.6 milliseconds is too short a length of time for a human to process. To put things in perspective, TimeAndDate reported that it typically takes a person 100 milliseconds to blink. That means the day will be shorter by dramatically less than the blink of an eye. However, even minuscule changes in time can throw off some of the technology that humanity relies on in modern times. Dr. Michael Wouters, time and frequency lead at the National Measurement Institute in Australia, told The Guardian that computer, GPS systems and electricity networks can go on the fritz if timing is off by a billionth of a second. He told the outlet that even banking systems could be thrown out of whack. Never miss a story — sign up for to stay up-to-date on the best of what PEOPLE has to offer, from celebrity news to compelling human interest stories. "We're transmitting data so quickly, and it all needs to be time tagged, so computers know what data goes where,' he said. The Tab reported that if things continue on this trend, a "leap second" might be introduced in 2029. This means that the day will be recorded as roughly one second longer on average. The outlet cited a report by the International Earth Rotation and Reference Systems Service and noted that one was previously added to clocks in 2016. It's worth noting that the length of a day has changed over the years. In the age of the dinosaurs (more than 50 million years ago), it took Earth 23 hours to finish a rotation. Two hundred million years from now, a day might last for as long as 25 hours. Read the original article on People
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The Independent
6 days ago
- Science
- The Independent
How Earth's rotation is making today feel like the shortest day ever
Earth 's rotation has recently accelerated, making some summer days fractionally shorter by milliseconds. This phenomenon, though unnoticeable in daily life, significantly impacts high-precision timekeeping systems like atomic clocks and GPS. Scientists at the International Earth Rotation and Reference Systems Service suggest the acceleration is due to a subtle shift in the Moon 's orbital alignment, reducing 'tidal braking'. However, other experts, such as Moscow State University astronomer Leonid Zotov, state the cause remains unexplained, possibly originating from within the Earth. The International Earth Rotation and Reference Systems Service is considering implementing a 'negative leap second' for the first time, potentially around 2029, to resynchronize global time.
The Independent
6 days ago
- Science
- The Independent
Time keeps on slipping - literally. Why today might have been the shortest day you ever experience
Some upcoming summer days are actually getting shorter, literally. Even if it's only by milliseconds. While the change won't be noticeable, Wednesday might technically be the shortest day you'll ever experience. That's because Earth completed its rotation approximately 1.3 to 1.6 milliseconds faster than the average 86,400 seconds. "In other words, we're not traveling back toward the Mesozoic in terms of rotation," Popular Mechanics reports. "The planet will eventually continue its steady deceleration — this is, of course, its natural tendency, but surface changes like polar ice melt can also contribute to the Earth's rotation slowing down." This phenomenon is invisible to daily life but of significant importance to high-precision timekeeping systems such as atomic clocks, GPS, and satellite networks. Scientists at the International Earth Rotation and Reference Systems Service attribute the acceleration to a subtle shift in the Moon 's orbital alignment, which, orbiting farther from Earth's equator this summer, has reduced the 'tidal braking' effect that normally slows our planet's spin. Others, such as Moscow State University astronomer Leonid Zotov, said the cause of this acceleration is unexplained. "Most scientists believe it is something inside the Earth," he told "Ocean and atmospheric models don't explain this huge acceleration." This spike in rotational speed marks the sixth occurrence of unusually fast days since 2020, with similar events expected to occur on July 22 and August 5. In response to the slight change, the International Earth Rotation and Reference Systems Service is now considering implementing a negative leap second, a rare adjustment that subtracts time from Coordinated Universal Time to resynchronize clocks with Earth's rotation. Such a correction has never been made before, but the growing trend may require one around 2029.
Forbes
20-06-2025
- Science
- Forbes
Get Ready For The Shortest Day Since Records Began As Earth Spins Faster
Earth could be about to record its fastest-ever rotation. Since 2020, Earth has been rotating faster than at any point since records began in 1973, with each successive year producing the shortest day. Last year, the shortest day was recorded on July 5, and Earth is expected to get close to this again on or close to July 9, July 22 and August 5, according to "Rapidly spinning globe. Symbolic of time passing, travel and other metaphors of space and time." Earth takes a nominal 24 hours to rotate once on its access, which is equal to 86,400 seconds. Until 2020, Earth's rotation had been gradually slowing down, and the shortest ever day recorded was just 1.05 milliseconds under 86,400 seconds. However, on July 19, 2020, Earth rotated 1.47 milliseconds less than 86,400 seconds. Last year, on July 5, it was even shorter at 1.66 milliseconds. Since 2020, Earth has seen 28 of its fastest days and predictions from International Earth Rotation and Reference Systems Service and U.S. Naval Observatory indicate that Earth will again rotate faster on July 9, July 22 or August 5. The uncertainty comes from the exact position of the moon, which acts as a drag factor, particularly when it's close to the equator. In the long-term, the moon is gradually slowing down the Earth's rotation, its gravitational pull causing tides and making Earth's orbital path around the sun slightly elliptical. Precise measurements of the length of a day come from atomic clocks and monitoring by the IERS. Scientists do not know why Earth's rotation has been speeding up since 2020. various factors are likely at play, including the motion of Earth's core and mantle, a shifting of mass due to the melting of ice sheets and glaciers, and variations in ocean currents and air movement. All of these could influence the day length by milliseconds. It could also be down to the 'Chandler wobble' — the movement of Earth's geographical poles across its surface. Historically, international timekeepers have added leap seconds to keep atomic time aligned with Earth's spin. However, since Earth is now rotating faster, not slower, so leap seconds are redundant. Instead, negative leap seconds— i.e., removing a second) — are being considered. IERS confirmed earlier this month that no leap second would be added in 2025. The last leap second was positive and used at the end of December 2016. Scientists are unsure what to do because the current speeding-up may be a blip in a longer trend of Earth's rotation slowing. It may seem trivial, but the fact that Earth is spinning faster in 2025, shaving milliseconds off the day, is critical for maintaining time accuracy worldwide. Maintaining alignment between Earth time and atomic time is crucial for GPS and satellite navigation, financial systems reliant on precise timestamps and synchronizing networks across the world.
