{"id":110646,"date":"2025-08-01T16:03:15","date_gmt":"2025-08-01T16:03:15","guid":{"rendered":"https:\/\/www.europesays.com\/us\/110646\/"},"modified":"2025-08-01T16:03:15","modified_gmt":"2025-08-01T16:03:15","slug":"heres-why-days-are-actually-getting-shorter-and-scientists-are-puzzled","status":"publish","type":"post","link":"https:\/\/www.europesays.com\/us\/110646\/","title":{"rendered":"Here\u2019s why days are (actually) getting shorter and scientists are puzzled"},"content":{"rendered":"

Earth\u2019s rotation is quietly speeding up\u2014some days this summer are ending over a millisecond early. As mills of seconds add up, timekeepers may face the unprecedented step of subtracting a \u201cnegative leap second\u201d to keep our clocks in sync.<\/strong><\/p>\n

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An atomic clock in the time laboratory of the Physikalisch-Technische Bundesanstalt (PTB) in Germany. These devices use lasers and atoms to calculate time with extreme precision. Julian Stratenschulte\/picture alliance\/dpa\/Getty Images<\/p>\n

Shorter Days on the Horizon<\/p>\n

This summer, Earth is rotating faster<\/strong> than ever\u2014so much so that some days are under 24 hours. On July 10, 2025, our planet completed a turn in 1.36 milliseconds less than the standard 86,400 seconds. More record-short days loom on July 22 and August 5, at 1.34 ms and 1.25 ms under 24 hours, respectively.<\/p>\n

Why Seconds Matter<\/p>\n

Atomic clocks\u2014our most precise timekeepers\u2014track time by counting atomic oscillations<\/strong><\/a> in a vacuum chamber. They define UTC<\/strong> (Coordinated Universal Time), the global standard that anchors everything from GPS satellites to financial trading. Yet Earth\u2019s actual rotation wobbles daily, thanks to the moon\u2019s pull, seasonal air shifts, and flows in our liquid core. Satellites monitor these tiny drifts by comparing Earth\u2019s spin against the fixed stars.<\/p>\n

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The spin rate of Earth is affected by many factors, but the moon and the tides have traditionally played a major role. NASA<\/p>\n

Leap Seconds and the Next Frontier<\/p>\n

Since 1972, scientists have added 27 leap seconds to sync UTC with a slowing Earth. But as Earth speeds up, we haven\u2019t needed one since 2016. In 2022, standards bodies voted to retire leap seconds by 2035. If the trend continues, we may need a negative leap second<\/strong>\u2014subtracting a second\u2014to keep UTC aligned. Experts estimate about a 40% chance of that before 2035.<\/p>\n

What\u2019s Speeding Up the Spin?<\/p>\n