Now, scientists have revealed exactly when the next shortest days will occur as Earth’s rotation speeds up once again<\/a>.<\/p>\n Scientists predict that July 22 and August 5 will be even shorter than July 9, at 1.38 and 1.51 milliseconds shorter than average.<\/p>\n This is because the moon will be at its furthest point from Earth, reducing how much the tides hold back the planet’s rotation.<\/p>\n Since an average blink lasts about 100 milliseconds, you won’t be able to notice this difference.<\/p>\n However, Earth’s rotation has been unexpectedly speeding up over the last few years, with atomic clocks picking up the change in 2020 and 2022.<\/a><\/p>\n While scientists have suggested multiple theories from changes in the atmosphere to the weakening magnetic field, the exact reason for the acceleration remains a mystery.<\/p>\n Scientists have found that two upcoming days this summer will be among the shortest ever recorded.\u00a0July 22 and August 5 will be even shorter than July 9, at 1.38 and 1.51 milliseconds shorter than average (stock image)\u00a0<\/p>\n Your browser does not support iframes.<\/p>\n Normally, the Earth takes 24 hours, or 86,400 seconds, to rotate fully on its axis in a ‘solar day’.<\/p>\n While this constant might be something we often take for granted, the Earth’s rotation isn’t actually stable.<\/p>\n On average, the Earth is actually slowing down by about two milliseconds per century.<\/p>\n This means that a T Rex in the Mesozoic era, about 250 million years ago, lived through days that were 23 hours long.<\/p>\n Even as early as the Bronze Age, the average day was about 0.47 seconds shorter, and in 200 million years’ time, the days will be 25 hours long.<\/p>\n This slowing is largely due to the pull of the moon in a process called tidal braking.<\/p>\n When the moon’s gravity pulls on Earth, it causes the oceans to bulge out slightly.<\/p>\n In addition to creating the tides, this tug actually pulls Earth backwards and slows its rotation.<\/p>\n These short days are caused by the moon being at its furthest from Earth. This reduces an effect called tidal braking and allows the planet to spin faster\u00a0\u00a0<\/p>\n The shortest days ever <\/p>\n 2023 July 16:\u00a0-1.31 milliseconds<\/p>\n 2024 July 5:\u00a0-1.66 milliseconds<\/p>\n 2025 July 9: -1.3 milliseconds<\/p>\n 2025 July 22: -1.38 milliseconds (prediction)<\/p>\n 2025 August 5:\u00a0-1.51 milliseconds (prediction)<\/p>\n Source: Time and Date\u00a0<\/a><\/p>\n However, when the moon is at its furthest point from Earth, known as the apogee, this pull is weaker and the planet can spin faster than normal.<\/p>\n That is why July 22 and August 5 will be so much faster than other days this year.<\/p>\n But these exceptionally short days are only possible because the Earth is currently in an unusual phase of acceleration.<\/p>\n This change has been so sudden that some experts think we will need to subtract a leap second for the first time ever in 2029.<\/a><\/p>\n Prior to 2020, there had never been a day much more than a millisecond shorter than average according to the US Naval Observatory and international Earth rotation services<\/a>.<\/p>\n Now, scientists have recorded a string of days more than 1.3 milliseconds shorter than normal.<\/p>\n The shortest day ever recorded occurred on July 5 last year, which was a full 1.66 milliseconds shorter.<\/p>\n Dr Leonid Zotov, a leading authority on Earth rotation at Moscow State University, told Time and Date<\/a>: ‘Nobody expected this. The cause of this acceleration is not explained.’<\/p>\n Since 2020, scientists using atomic clocks have noticed that Earth’s acceleration has been accelerating. But scientists are not sure why this is taking place\u00a0 (stock image)\u00a0<\/p>\n Overall, scientists expected the planet’s rotation to slow. This is partly due to the slowing rotation of the inner core, which affects Earth’s rotation in space\u00a0<\/p>\n Most scientists believe that this is due to something changing deep within Earth’s core, which is affecting the planet’s momentum.<\/p>\n In the future, Dr Zotov and other scientists expect that the trend will return to gradual slowing.<\/p>\n ‘I think we have reached the minimum. Sooner or later, Earth will decelerate,’ says Dr Zotov.<\/p>\n This is because there are a number of factors which are jointly working to slow the planet down.<\/p>\n In addition to tidal braking, scientists also found that the planet’s inner core began to slow around 2010 and is now moving backwards, subtly affecting the Earth’s rotation in space<\/a>.<\/p>\n This is expected to slightly slow the planet down over the coming years.<\/p>\n![\"Scientists](\"https:\/\/www.europesays.com\/uk\/wp-content\/uploads\/2025\/07\/100111763-14892833-Scientists_have_found_that_three_days_this_summer_July_9_July_22-a-18_17521454791.jpeg\")
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