The rotation of the Earth around its axis showed the highest speed in the last 50 years in 2020. According to Time and Date, only in the period, 28 days with this pattern were recorded since the beginning of monitoring, in the 1970s. the trend remains, it will imply in the future that a given year has one second less than the others.
Such changes are accompanied by several atomic clocks around the world, responsible for measuring Coordinated Universal Time (UTC), a system followed by countries. When the astronomical time defined by the time it takes the planet to do a full rotation deviates from UTC by more than 0.4 seconds, the latter receives an adjustment.
The change occurs in one second, known as a leap second – also called an interim or additional second. When this is not done, the measurement of time based on rotation may differ from atomic measurement, due to an irregular and decreasing variation in the speed of movement.
“It is quite possible that a negative second leap will be necessary if the Earth’s rate of rotation increases further, but it is too early to say whether this is likely to happen. There are international discussions taking place about the future of these actions, while there are also discussions to end these adjustments, ”commented Peter Whibberley, scientist at the UK’s National Physics Laboratory to The Telegraph.
According to the US National Institute of Standards and Technology (NIST), the model has its pros and cons. It is advantageous to ensure the synchronization of astronomical observations with the clock time. However, it can cause problems for some data logging applications and telecommunications infrastructure.
Irregular speed of Earth rotation
The rotation of the planet varies over time as a result of climatic and geological events. Among the main causes, tidal accelerations, movement of the Earth’s crust relative to its nucleus and atmospheric pressure stand out. Such differences are observed through the movement of the planet in relation to distant astronomical objects and the use of mathematical formulas to calculate the average solar day (24h), equivalent to a rotation of the Earth (86.4 thousand seconds).