Headline: Earth's Rotation Speeding Up: Scientists Weigh Potential Impact of Negative Leap Second by 2029

Scientists are observing that the Earth's rotation is increasing, leading to days that are a few milliseconds shorter. This seemingly small change could have significant consequences for global timekeeping systems.

Currently, leap seconds are added to atomic clocks to compensate for the Earth’s slowing rotation. However, if the current trend of faster rotation persists, experts predict that we may need to subtract a leap second by 2029 – a historic first. This adjustment would represent a significant shift in how we synchronize human-made time with the natural rhythms of our planet, demonstrating the subtle yet dynamic forces at play.

The Evolution of Earth's Day Length

A complete Earth rotation takes approximately 86,400 seconds, defining a day. However, this duration is subject to variations due to natural forces, ranging from gravitational influences to internal geophysical events.

Historically, the Earth's rotation has been gradually slowing. In the age of dinosaurs, days were only 23 hours long. During the Bronze Age, days were shorter by approximately half a second compared to today. Scientists project that days could eventually extend to 25 hours, but this is estimated to occur in approximately 200 million years.

Changing Rotation: Implications for Day Length

Since 2020, the Earth's spin has been gradually increasing, surprising many scientists. The International Earth Rotation and Reference Systems Service (IERS) in Washington, D.C., has confirmed this ongoing acceleration.

As a result, days are shorter by milliseconds. If this continues, a negative leap second might be necessary for Coordinated Universal Time (UTC) by 2029. Leap seconds are one-second adjustments periodically added to atomic clocks to account for the Earth's irregular rotation, ensuring synchronization between atomic time and the planet's actual spin.

Until now, leap seconds have been added exclusively to compensate for the Earth's slowing rotation. The potential removal of a second from atomic time would be unprecedented, but necessary to maintain accurate alignment with Earth's rotation.

Predicted Shortest Days in 2025

According to timeanddate.com, the shorter day trend is expected to persist into 2025. Scientists have identified the following dates as potential peaks in the Earth's spin:

• July 9, 2025
• July 22, 2025
• August 5, 2025

Reports from USA Today suggest that on August 5, the day could be 1.51 milliseconds shorter than the standard 24 hours.

Unraveling the Cause of Earth's Acceleration

The precise cause of this recent acceleration remains elusive. Scientists are considering several possibilities:

• Seismic activity
• Changes in the Earth's core dynamics
• Glacial rebound
• Shifts in ocean currents and atmospheric pressure

Leonid Zotov, a researcher at Moscow State University, expressed surprise at the phenomenon. He co-authored a 2022 study on the subject but acknowledges that no existing model fully explains it. While oceanic and atmospheric changes may influence Earth's spin, they are likely insufficient to account for the current significant acceleration. Some researchers propose that movement within the Earth's molten outer core could be influencing rotational speed.

Leap Second Removal: A Routine Adjustment

Scientists reassure that there is no cause for alarm. While an increase in Earth's rotation is uncommon, such fluctuations have occurred throughout history. Over extended periods, the planet continues its trend toward gradual slowdown.

The potential removal of a leap second in 2029 is viewed as a routine technical correction to keep atomic clocks aligned with Earth's rotation. It will not impact daily life, electronic devices, or global operations. However, it highlights the complex natural forces that influence even the most seemingly constant aspects of our lives, like time.