The days are getting shorter and not just because summer is waning in the Northern Hemisphere.

On Tuesday, Aug. 5, Earth's solar day will be ever so slightly shorter than usual 24 hours, according to Timeanddate.com, making it not only one of the shortest days of 2025, but also since records began.

At just 1.25 milliseconds under the 86,400-second mark, it won't be noticeable, but it's part of a puzzling trend that's baffling scientists: Earth is spinning faster. After decades of slowing down, our planet's rotation has been speeding up in recent years — and timekeepers have no definitive explanation.