Earth completes rotation in less than 24 hours; sets record
Earth set a new record for the shortest day on July 29 by completing a full rotation on its axis in 1.59 milliseconds less than the standard 24 hours. The speed of the rotation has been increasing recently, but the reasons are currently unknown. If Earth continues to rotate faster, negative leap seconds would be introduced, and it would play havoc on communication systems.
- It might seem that Earth is becoming faster, but when much longer time periods are considered, it is actually slowing down. The planet is taking a few milliseconds more every century to complete one rotation.
- However, the introduction of negative leap seconds seems unnecessary, and "it is a risky practice that does more harm than good," as per tech giants like Meta.
Earth has been speeding up for quite some time, and the year 2020 witnessed the shortest recorded month since the 1960s. On July 19 that year, the day was 1.47 milliseconds shorter. The heavenly body continued to spin faster in 2021, but no new records were set. Scientists believe that our planet is entering a 50-year phase of shorter days right now.
Some scientists believe that Earth has been exhibiting an increased rotation pace because of climatic changes, tidal movements, and processes in its core. Others claim that the movement of the planet's geographic poles across its surface might be responsible. This phenomenon is called the Chandler wobble and is similar to the quivering of a spinning top when it starts gaining momentum or becomes slower.
Negative leap seconds might have to be introduced to ensure the rate at which Earth orbits the Sun is consistent with the measurement from atomic clocks. However, software relying on timers will be affected as clocks run from 23:59:59 to 23:59:60 before resetting to 00:00:00 with leap seconds. With negative leap seconds, clocks will change from 23:59:58 to 00:00:00, thus also confusing the software.
The concept of leap seconds was introduced in 1972 to keep the Coordinated Universal Time (UTC)—the primary time standard by which clocks worldwide are regulated—in sync with the long-term slowdown of Earth's rotation. It has been used 27 times, and the tech industry is trying to ensure that no new ones are added. This will prevent issues with the functioning of computer networks.