Today will be one of the shortest days in history. Here's why
The planet's rotation will be approximately 1.34 milliseconds less than the usual 24 hours we are used to. Although you won't be able to feel the difference, the shortened day is part of a recent trend in the planet's rotation that scientists have not been able to pinpoint the cause of, according to Space.com.
The invention of the atomic clock in 1973 allowed scientists to begin recording the speed of the rotation of the Earth through exact atomic frequencies, as opposed to regular manufactured clocks which are prone to slight errors, according to the National Institute of Standards and Technology's website.
From 1973 to 2020, the shortest day ever recorded was only 1.05 milliseconds shorter than 24 hours, Space.com reads. Since 2020, however, the Earth has repeatedly broken its own speed record since then, with the shortest day ever recorded being July 5, 2024 at 1.66 milliseconds shy of 24 hours.
The shortest day in 2025 was July 10, at 1.36 milliseconds short of 24 hours. July 22 is expected to finish out the year as the second shortest day, according to Space.com.
If this trend continues, scientists may need to subtract a second from the atomic clock by 2029, Space.com reads.
Although scientists haven't been able to determine the exact cause of the rotation, a 2024 study suggests melting polar ice caps and rising sea levels might be affecting Earth's spin. Another theory is that something in the Earth's core is influencing the Earth's rotation, according to Space.com.
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'This newly approved program will buy decision makers two extra years to prepare — though most likely to relax, as there is an 80% chance of ruling out impact — while providing key experience-based lessons for handling future potential impactors to be discovered by Vera Rubin,' de Wit said. And because of the twists and turns of YR4's tale thus far, asteroids that have potential to affect the moon could become objects of even more intense study in the future. 'If this really is a thing that we only have to worry about every 5,000 years or something, then maybe that's less pressing,' Rivkin said. 'But even just asking what would we do if we did see something that was going to hit the moon is at least something that we can now start thinking about.' Sign up for CNN's Wonder Theory science newsletter. Explore the universe with news on fascinating discoveries, scientific advancements and more.
