Earth's Rotation Speeding Up: What It Means for Day Length

Earth's rotation is changing, leading to shorter days. Scientists have found that Earth is spinning faster than usual, causing days to be shorter by a few milliseconds. This change has implications for global timekeeping systems. Leap seconds are typically added to atomic clocks to match Earth's slower rotation, but experts predict that by 2029, we may need to subtract a leap second for the first time. This shift highlights how human-made timekeeping aligns with Earth's dynamic changes.

Earth's rotation duration is not constant due to natural phenomena like gravitational forces and geophysical changes. Historically, days have varied in length. Since 2020, Earth has been spinning faster, resulting in shorter days by milliseconds. If this trend continues, a leap second may need to be removed from Coordinated Universal Time by 2029, a first in history.

Scientists expect the trend of shorter days to continue into 2025, with specific dates like July 9, July 22, and August 5 marked for Earth's fastest spin. The reason behind this acceleration remains unclear, with possibilities including seismic activity, core dynamics changes, glacial rebound, and ocean currents shifts.

Despite the unexpected acceleration, scientists remain calm, noting that Earth's rotation fluctuations are not unprecedented. The potential removal of a leap second in 2029 is a technical adjustment to maintain clock accuracy with Earth's rotation, without impacting daily life or global operations.