The tides that push the Moon away are slowing Earth down too. Days are getting longer by about 1.7 milliseconds per century.

It sounds like nothing, and over a human life it is. Over deep time it isn't: sediment records suggest a day lasted around 18 hours 1.4 billion years ago, and the Moon was noticeably closer. Leap seconds exist partly because of this.

Source: Meyers & Malinverno, PNAS (2018) · checked Aug 2026

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The tides that push the Moon away are slowing Earth down too. Days are getting longer by about 1.7 milliseconds per century.

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The tides that push the Moon away are slowing Earth down too. Days are getting longer by about 1.7 milliseconds per century.

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