2024-03-29 03:51:04
This is because the speed of the Earth’s rotation around its axis fluctuates slightly, meaning that one complete rotation is not always exactly one day.
Now, for the first time, a US scientist is calling for the introduction of a “negative” leap second – that is, subtracting a second, which would cause time to “stand still for a moment”. A positive leap second is the addition of a second when the Earth’s rotation was too slow, and a negative leap second is the subtraction of a second when the Earth’s rotation is too fast.
University of California, US geophysicist Duncan Agnew says a negative leap second should be introduced in 2029 to account for the fact that the Earth is spinning too fast, but he warns it could cause “unprecedented” problems for the smart for phones and computers.
Coordinated Universal Time (UTC) is defined by complex, highly accurate “atomic clocks” around the world that operate accurately and continuously.
However, these atomic clocks do not precisely match observed “solar time,” which historically defines days as one revolution of the Earth.
Because of the Moon’s pull, the time it takes for the planet to make one revolution changes, so the two time systems diverge.
Since 1972 leap second has been added 27 times, most recently in 2016.
However, it is reported that from 2020 The rotation of the earth is not slowing down, but speeding up. Therefore, in the future, it may be necessary to subtract, rather than add, a leap second to synchronize the observed solar time with the clocks.
“Until a few years ago, it was expected that leap seconds would always be positive and that they would become more frequent,” said Professor Agnew. “However, if we look at the changes in Earth’s rotation that cause leap seconds, and look at what causes these changes, it turns out that a negative change is very likely.”
The problem is that if the computer network doesn’t know about leap seconds, it won’t sync with everyone else. For example, if the online store’s computer and your bank’s computer record different times, clicking the “order” button will appear to be two actions at different times, instead of one.
“One second doesn’t seem like much, but in today’s world, getting the timing wrong can cause big problems,” said Professor Agnew. “Many systems now have software that can accept an extra second, but few (if any) systems can subtract a second, so a negative leap second is likely to cause a lot of trouble.”
The Earth’s rotation frequency is determined annually by several factors, one of which is the Earth’s liquid core. The very slow motions of different parts of the core interact to create the Earth’s magnetic field. These changing motions also cause the Earth to spin faster or slower.
In their new study, published in the journal NatureProfessor D. Agnew claims that melting ice at high latitudes due to global warming is an additional factor slowing the Earth’s rotation.
“As the ice melts, the water spreads throughout the ocean, increasing the Earth’s ‘resistance’ to angular acceleration, which in turn slows the planet’s rotation. So while the Earth’s rotation has generally been speeding up, global warming is slowing it down, delaying the need for a negative leap second. If the Earth’s rotation had not slowed down due to the melting ice, the negative leap second would have been needed three years earlier – in 2026,” explains Professor D. Agnew.
in 2022 scientists have voted to abandon the leap second system entirely, but that may not happen until 2035 at the earliest. – by then, you may need a negative leap second, writes the Daily Mail.
2024-03-29 03:51:04