The Earth will experience a rotation speed of 86,399.99867 seconds on Tuesday, August 5, marking one of the shortest days of 2025. This occurs due to a combination of factors, including winds in the atmosphere, oceanic fluid circulation, and the Moon’s gravitational pull.
Currently, the Earth’s sidereal day is approximately 23 hours, 56 minutes, and 4 seconds long, while its solar day averages around 24 hours. However, the length of both days decreases slightly on August 5 due to these factors.
The deviation from a perfect 24-hour cycle has been accurately measured since the 1970s using atomic clocks and astronomy. To correct for this, leap seconds are added to our timekeeping system.
Global positioning systems (GPS) rely on precise timing to provide accurate location data. A variation in the Earth’s rotation speed could result in position errors of up to 62 centimeters at the equator if not corrected.
The cause of the Earth’s slowing down lies in its oblate shape and the redistribution of mass due to climate change and earthquakes. Additionally, the Moon’s gravitational pull causes tidal drag on the oceans, leading to a slowdown in the Earth’s rotation energy.
However, from 2020 onwards, there has been an unexpected increase in the Earth’s rotational speed, possibly resulting from angular momentum exchange between the core and mantle.
To account for these changes, scientists have identified dates when the Moon’s position slows down the Earth twice per orbit. On August 5, this effect is more pronounced due to the alignment of celestial bodies. This slight variation will not be noticeable to humans but will be apparent to precision atomic clocks and quasar-referenced astronomical measurements.
Source: https://theconversation.com/why-on-earth-is-the-planets-day-getting-shorter-260946