The Earth Just Recorded its Shortest Day Ever and Here is How You Are Affected

Just in case you needed something else to be anxious about.

The Earth is spinning faster than ever and this summer recorded its shortest day since the atomic clock standard was adopted in 1970, shaving 1.59 milliseconds off its rotation—but what exactly does that mean? Here's what might be happening, according to scientists.

1
A Day Like Any Other

A tired woman in bed hits her alarm clock to stop it from going off.
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June 29 was the record-breaking shortest day—but scientists are reminding everyone there have been shorter days before official records began. 70 million years ago, a normal day on Earth was approximately 23 1/2 hours, according to a 2020 study published in Paleoceanography and Paleoclimatology. So, does this mean we shouldn't panic? "It's a completely normal thing," Stephen Merkowitz, scientist and project manager at NASA's Goddard Space Flight Center, told CBS News. "There's nothing magical or special about this. It's not such an extreme data point that all the scientists are going to wake up and go, what's going on?"

2
Should We Be Worried?

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"Our day-to-day existence doesn't even recognize that millisecond," says Dennis McCarthy, retired director of time at the US Naval Observatory. "But if these things add up, then it could change the rate at which we insert a leap second." McCarthy says that when milliseconds build up over time, a leap second is added to the clock so our time matches Earth's. Since 1972, there have been 27 leap seconds added to the clock.

3
Are the Days Actually Getting Longer?

Woman sitting on top of skyscraper overlooking the city at sunrise.
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Despite the shortest day just recorded, days are actually getting longer, scientists say, and they don't know why. One theory is that the melting glaciers are causing Earth to become rounder, which helps the planet turn faster. The example used is how a ballerina spins faster when her arms are down at her sides, and slower when they are held out.

4
What Causes Changes In Earth's Rotation?

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Earthquakes can cause changes in the Earth's rotation, scientists say. The Great Tōhoku earthquake of 2011 was said to speed up the rotation by 1.8 microseconds and moved the Earth's figure axis by about 6 1/2 inches, according to geophysicist Richard Gross at NASA's Jet Propulsion Laboratory in Pasadena, CA. "By changing the distribution of the Earth's mass, the Japanese earthquake should have caused the Earth to rotate a bit faster, shortening the length of the day by about 1.8 microseconds," Gross told SPACE.com. "This shift in the position of the figure axis will cause the Earth to wobble a bit differently as it rotates, but will not cause a shift of the Earth's axis in space – only external forces like the gravitational attraction of the sun, moon, and planets can do that," Gross said.

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5
What About Electronics?

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"Although it will have no effect on our daily lives, there could be serious implications for technology such as GPS satellites, smartphones, computers and communication networks, all of which rely on extremely accurate timing systems," says Dr. Alastair Gunn, a radio astronomer at the Jodrell Bank Center for Astrophysics at the University of Manchester. "But such problems are ultimately surmountable, perhaps simply by subtracting a leap second rather than adding one."

Ferozan Mast
Ferozan Mast is a science, health and wellness writer with a passion for making science and research-backed information accessible to a general audience. Read more
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