Overview

• Earth’s rotation has accelerated this summer, producing record-short days with July 10 clocked at 1.36 milliseconds under 24 hours.
• Forecasts project July 22 and August 5 will see further short days of about 1.34 and 1.25 milliseconds less than a full rotation.
• Positive leap seconds are scheduled for retirement by 2035, prompting experts to consider a negative leap second to realign atomic clocks with astronomical time.
• Specialists remain divided on the proposal, warning that subtracting a second could trigger failures in GPS, high-speed communications and financial networks.
• Natural forces such as lunar gravity shifts, seasonal atmospheric dynamics and movements in Earth’s liquid core are driving the unusual acceleration.