Scientists around the world are having a headache because of this problem.
Atomic clocks are used to accurately record the time of a day at the millisecond level. Since its invention in 1970, a day has become slightly longer than 24 hours. But according to the latest published data, time is passing at its fastest rate in the past 50 years.
The Earth’s rotation is faster than usual , which means the length of a day is currently shorter than 24 hours . Scientists around the world are debating whether to erase a second to bring time back to match the Earth’s rotation.
Time is passing at the fastest pace in the past 50 years.
While the so-called “negative leap second” has never been implemented before. A total of 27 “leap seconds” have been added since 1970, to keep the atomic clock’s time in line with the Earth’s rotation.
The reason is that for decades, the Earth rotated at a slower rate than normal and took more than 24 hours to complete one revolution. As we all know, the time of a day is equivalent to the time it takes the Earth to complete one revolution.
Since the 1970s, atomic clocks have kept super-accurate records of the length of a day. And found that over the past 50 years, the Earth has taken more than 24 hours to complete one revolution, even if only a little more.
On average, currently a day is 0.5 milliseconds shorter than 24 hours.
However, by mid-2020, this trend has reversed and the Earth takes less than 24 hours to complete one rotation. On July 19, 2020, a day 1.4602 milliseconds shorter than the typical 24 hours, this is the shortest day since atomic clocks worked.
On average, currently a day is 0.5 milliseconds shorter than 24 hours. This tiny loss of time can only be detected by atomic clocks, and seems to have no effect on our lives.
But these small changes can have a big impact. Satellites and communication devices rely on real-time solar time, determined by the positions of the stars, Moon, and Sun. In other words, based on the actual rotational speed of the Earth.
This small change can have a big impact.
If this disparity is allowed to happen without a solution such as adding leap seconds, satellite systems and communication equipment will suffer. That is why the current controversial topic is whether to add negative leap seconds and if so, when.
“It is certain that the Earth is rotating faster than at any point in 50 years,” said natural scientist Peter Whibberley, senior researcher in the Time and Frequency group of the US National Physics Laboratory. past year. It is very possible that a leap second is needed if the Earth’s rotation rate continues to increase, but it may be too early to decide if it can happen.”