EARTH’S SPIN

Description

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Context

On July 29, the Earth broke its record for the shortest day as it completed a full spin in 1.59 milliseconds less than its standard 24-hour rotation.

Background

Earth recently has been increasing its speed. Back in 2020, the Earth saw its shortest month that has ever been recorded since the 1960s. On July 19 of that year, the shortest of all time was measured. It was 1.47 milliseconds shorter than a typical 24-hour day.

Cause of increase in speed

The cause of the differing speed of Earth's spin is still unknown. But scientists speculate that this could be because of processes in the inner or outer layers of the core, oceans, tides or even changes in climate.
Some researchers also believe that this could be related to the movement of Earth's geographic poles across its surface, known as the "Chandler wobble". In simpler words, this is similar to the quiver one sees when a spinning top starts gaining momentum or slows down.

Impact and solution

If the Earth continues to spin at an increasing rate it could lead to the introduction of the negative leap seconds, in a bid to keep the rate that the Earth orbits the Sun consistent with the measurement from atomic clocks.

Attempt Daily Quiz

· Negative leap seconds, the opposite of regular leap seconds, involve subtracting time from the Earth's timekeeping system so that it aligns with astronomical time, or the time it actually takes the Earth to complete a rotation. Co-ordinated universal time, or UTC, is the time standard used to adjust clocks on Earth.

However, the negative leap second would have potentially confusing consequences for smartphones, computers and communications systems.
The leap second "mainly benefits scientists and astronomers" but that it is a "risky practice that does more harm than good". This is because the clock progresses from 23:59:59 to 23:59:60 before resetting to 00:00:00. A time jump like this can, therefore, crash programmes and corrupt data due to the timestamps on the data storage.
Should a negative leap second occur, the clock will change from 23:59:58 to 00:00:00, and this could have a "devastating effect" on the software relying on timers and schedulers.
To solve this, international timekeepers may need to add a negative leap second - a "drop second".