Have you ever wished you could take back even just a second of your life? Well, one day that might become a reality. No, we’re not talking about time travel.
a The study was published Wednesday in the journal Nature Our calendars and clocks are based on the amount of time it takes for the Earth to rotate completely, so changes in the Earth’s rotation (which is not as consistent as you might think) affect how time is measured. We investigated how this can have a significant impact on
The paper found that melting polar ice sheets are redistributing large amounts of water from the North and South poles to the world’s oceans. This caused the Earth’s rotation to slow down significantly.
You can see this phenomenon occur when a figure skater raises their arms above their head and spins quickly. When she lowers her arms, her rotation slows down. Therefore, as more and more water weight is diverted away from the poles and distributed around the Earth’s bulging center, the planet’s rotation also slows down.
“Global warming is progressing to the point where its effects are felt on the rotational speed of the entire planet,” geophysicist Duncan Carr Agnew, lead author of the study, said in a statement to Global News. “Such a rotational shift has never been seen before, and it once again emphasizes that we live in a time of unprecedented change.”
But at the same time, an opposing force is increasing the speed of the Earth. For about 50 years, Earth’s core trends have continued to accelerate the Earth.
After modeling the effects of these two opposing forces, Agnew calculated that by 2029, there would need to be a “minus leap second” event, when the world’s clocks go back one second for the first time in history.
“This has never happened before, and it poses a major challenge in ensuring that all parts of the global timekeeping infrastructure display the same time,” Agnew said. said.
The Earth has been moving towards the need for negative leap seconds for decades. But Agnew found that the slowing effect of melting ice in the Earth’s polar regions is counteracting this rapid rate, possibly delaying this global second by about three years. , he calculated.
While global warming has clearly postponed this timing problem, Agnew insists his research should not be seen as a positive side effect of climate change.
“I think thinking positively about global warming because of its impact on timekeeping is like looking at a polluted lake and seeing its interesting colors and thinking positively,” he wrote.
Timing trading tips
To understand why we need negative leap seconds, we first need to understand how the world tells time.
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Before the invention of atomic clocks, a second was defined as 1/86400 of a day, and a day was defined as one rotation of the Earth. The only problem is that the Earth can spin faster or slower. This means that the length of a second can vary from day to day.
In 1967, timekeepers introduced atomic clocks as a means to accurately determine the second based on the vibrations of cesium particles as they emit radiation. As you might imagine, this quantum process is much more consistent than the motion of her 5,700 kilogram sphere flying through space.
The first cesium atomic clock manufactured by the National Physical Laboratory in Middlesex, England, photographed in 1955.
Science and Society Image Library/SSPL/Getty Images
However, for various reasons, timekeepers still wanted their clocks to keep pace with the Earth’s rotation, and so the systems of Coordinated Universal Time (UTC) based on atomic clocks and Universal Time (UT1) based on the Earth’s rotation were created. was adopted. , was devised.
Since 1972, the world has experienced 27 leap seconds (one second added to clocks) to keep time in both UTC and UT1.
This is because UT1 (astronomical time) typically runs slightly slower (just a millisecond) than UTC (atomic time). Every day’s fractional seconds add up to total seconds every few years, so leap seconds may be added in some cases. Instead of 11:59:59 changing to midnight, an additional second occurs at 11:59:60.
This leap second system seemed to assume that astronomical time was always slower than atomic time. Recently, however, the Earth’s velocity has been accelerating due to trends in the Earth’s core.
you spin me around
For thousands of years, the Earth has generally slowed down. But in the mid-2010s, scientists observed that the rate of deceleration was decreasing and the Earth was actually starting to accelerate.
This happens because the Earth’s core is a molten liquid and there are electrical currents that cause it to rotate. Agnew said that since the 1970s, the core’s rotation has been steadily slowing, which is causing the solid Earth around it to speed up.
This may seem counterintuitive, but when one rotating mass slows down, angular momentum is transferred to the same rotatable mass that is connected to it. So if the core slows down, it means the rest of the Earth speeds up.
Agnew shared a video to explain this phenomenon. A man sits on a rotating chair and holds a bicycle wheel. When you spin the bicycle wheel and gain momentum, the stool remains stationary and does not rotate. However, when the man slows down the spinning bicycle wheel, his stool begins to spin. When the wheel stops rotating completely, the stool will rotate even faster.
Core has been accelerating toward acceleration for about 50 years since 1972, Agnew said. However, the rapid melting of ice at both poles since 1990 has masked this effect.
Without the effects of melting ice, Earth would need a negative leap second in 2026 instead of 2029.
As for the fundamental reason why the Earth’s core is slowing, “we don’t know,” Agnew said.
Leap second limit
For decades, astronomers have recorded universal astronomical time with a convenient little leap second. But computer system operators said such additions will not be easy with all the precision technology the world currently relies on. 2012, some computer systems I mishandled leap seconds.Experts say it’s causing problems for Reddit, Linux, Qantas and more.
In 2022, Decided by the world’s timekeepers Starting in the 2030s, the standards for inserting and deleting leap seconds will change, making this possibility much less likely.
Tech companies like Google and Amazon have unilaterally enacted their own solutions to the leap second problem by gradually adding up subseconds over the course of a full day.
But subtracting leap seconds instead of adding them introduces a whole new set of problems. Computer programs are designed to add time rather than subtract it, so skipping a second can be difficult.
“Many computer programs for leap seconds assume that everything is positive, so these would have to be rewritten and are even less likely to run correctly on all computers,” Agnew said. Ta.
But why go through all this trouble to be accurate down to the second?
“One second may not seem like a big deal, but (for example) the EU standards for the timing of stock market trades are:
The time of every transaction must be accurate to 0.001 seconds,” he explained, adding that many systems, including power grids, depend on accurate time.
Agnew hopes his paper will encourage the timekeeping community to do away with leap seconds altogether.
“All this means is that we relax the requirement that UTC and UT1 must not be more than 1 second apart. If these timescales can differ by up to 1 minute, it is possible for a negative step to be taken. The potential for growth will be very low, and positive steps can be planned decades in advance.”
— With files from The Associated Press
