Earth's Spin: Why Days Are Getting Shorter

Our planet is in a bit of a hurry lately. Earth has been spinning faster than usual, making some days shorter than the standard 24 hours. This isn't just a one-time thing. It's happening more often, and scientists are paying close attention. On July 9, 2025, Earth completed a full rotation in just under 24 hours. It was only a tiny bit shorter, about 1. 3 to 1. 6 milliseconds, but it was the shortest day ever recorded. And it's not over yet. Two more short days are expected this summer, on July 22 and August 5. So, what's causing this speed-up? Earth's rotation isn't perfectly steady. It can speed up or slow down due to various forces. Over long periods, the moon's gravity actually slows Earth down. This is because the moon's pull creates tides, which act like a brake on Earth's spin. But over shorter periods, like days or months, Earth can speed up. The moon plays a big role in this. On July 9, the moon was at its farthest point from Earth's equator. This unusual position changed Earth's wobble, making it spin a bit faster. The same thing will happen on July 22 and August 5. Scientists have been tracking Earth's rotation very precisely since the 1960s using atomic clocks. These clocks can measure tiny changes in the length of a day. By comparing Earth's time with atomic time, scientists can see how much the planet's rotation varies. This speed-up could lead to something unprecedented: a negative leap second. Normally, when Earth slows down, scientists add a leap second to keep time in sync. But if Earth keeps speeding up, they might need to remove a second instead. This has never been done before, and it could happen around 2029.