For decades, Earth took longer to finish its rotation but it all changed a year ago.
But in 2020, the opposite happened - We have had the fastest 28 days on record since 1960. In 2020, the Earth's rotation varied plus or minus 1.5 milliseconds. Where 2020 felt for most people a year that spanned indefinitely from crisis to shutdown and back again, the year actually zoomed in at record speed.
So in a way, scientists believe that the time space of each day has reduced just slightly from the common 24 hours we are aware of. On the shortest day of the year, July 5, the Earth completed a rotation of 1.0516 milliseconds, more than 86,400 seconds.
What Have The Scientists Found?
To determine the length of each day on Earth, scientists at the International Earth Rotation and Reference Systems Service (IERS) measure the precise moment a fixed star passes a location in the sky.
The astronomical time is the time it takes for the Earth to make a full rotation.
If the Earth is indeed spinning faster, then their timing can also be affected.According to the Telegraph, there is no denying that Earth's rotational speed has increased in the last five decades, but it is too soon to decide whether the addition of "negative leap" is required.
However, seeing as the Earth has been consistently been slowing rather than speeding up its spin, there hasn't been a need to add a negative leap second before. Though the difference does cause challenges for worldwide timekeepers.
The speed of the Earth's rotation varies constantly because of the complex motion of its molten core, oceans and atmosphere, as well as the effect of celestial bodies such as the Moon. UTC, on the other hand, is based on global atomic time, which is tracked with 400 ultra-sensitive atomic clocks, located in 90 laboratories around the world.
Till date scientists had been "adding" this "leap second" either at the end of June or in December, roughly around New Year's Eve.
It is known that the rotation time on the Earth's axis varies slightly due to atmospheric pressure, wind, ocean currents and the motion of the center of our planet, but it is hard for worldwide time controllers to use ultra-precise atomic clocks to measure the global time that each person sets his clocks. Since the development of the atomic clock in the 1960s, "leap seconds" have been added 27 times to compensate slowing down rotation, According to EarthSky.org. This goes in direct opposition of previous records, under which the planet took longer than 24 hours to complete a rotation.
Critics say, for this reason, introducing a negative leap second could lead to digital issues, and websites crashing.
On average, the days are now passing 0.5 seconds shy of 24 full hours. When this time deviates by over 0.4 seconds, the UTC may have to be adjusted.
To those living out their usual days, half a second likely won't matter, but it could matter for things like satellites and communication relays, which rely on atomic time aligning near exactly with solar time.
In 2016, scientists added a "leap second" to keep our planet in sync - but this would be the first "negative leap second".