Earth broke the record for the shortest day ever

(CNN) – If it seems to you that there is less time in the day, you are right.

Scientists have recorded the shortest day on Earth since the invention of the atomic clock.

According to the International Earth Rotation and Reference Systems Service, an organization responsible for measuring time around the world, on June 29, our planet’s rotation lasted 1.59 milliseconds less than a typical 24-hour day.

One revolution is the time it takes the Earth to rotate once on its axis, which is about 84,600 seconds.

The previous record was documented on July 19, 2020, when today’s measurement was 1.47 milliseconds lower than usual.

The atomic clock is a standard unit of measurement used since the 1950s to determine time and measure the Earth’s rotation, said Dennis McCarthy, retired time director at the US Naval Observatory.

Although June 29 broke the record for the shortest day in modern history, there were much shorter days on Earth, he said.

When dinosaurs were still roaming the planet 70 million years ago, one day on Earth lasted about 23 and a half hours, according to a 2020 study published in the Academic Journal. Paleobiology and Paleoclimatology.

Since 1820, scientists have documented that the Earth’s rotation is slowing, according to NASA. However, in recent years, McCarthy said, it has begun to accelerate.

Why increase speed?

McCarthy said researchers don’t have a definitive answer as to how or why the Earth is spinning a little faster, but it could be due to glacial equilibrium adaptation, or Earth’s motion due to melting ice.

He said the Earth is a little wider than it is high, making it an oblate sphere. McCarthy said that polar glaciers weigh heavily on the Earth’s crust at the North and South Poles.

He said that because the poles are melting due to the climate crisis, there is less pressure on the top and bottom of the planet, pushing up the crust and making the Earth round. The circular shape helps the planet spin faster, McCarthy said.

It’s the same phenomenon that snowboarders use to speed up and slow down, he said.

He said that when skaters extend their arms away from their bodies as they spin, they need more force to spin.

McCarthy said that when their arms are close to the body, their speed increases because their body mass is closer to their center of gravity.

He said that when the Earth becomes round, its mass approaches its center, which increases the speed of its rotation.

Remove leap second (or extra second)

Since researchers began measuring the Earth’s rotation rate using atomic clocks, McCarthy said, the Earth has been slowing down.

“Our daily lives don’t even recognize the millisecond,” McCarthy said. “But if these things come together, it can change the speed at which we enter a leap second.”

In cases where milliseconds accumulate over time, he said, the scientific community has added an extra second to the clock to slow our time to match Earth time. An additional 27 seconds have been added since 1972, according to EarthSky.

McCarthy said: Since the Earth is now spinning faster, a leap second must be subtracted in order for our clock to adjust to the Earth’s increasing rotation speed.

If the planet continues in this rotational trend, he said, the leap second suppression will likely not be necessary for another three or four years.

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