Atomic Clocks and Astronomical Measurements Reveal Earth’s Mysterious Slowdown After Years of Acceleration.
In June 2022, humanity experienced the shortest day in half a century, a result of many years of Earth’s acceleration, causing a day to no longer fit into the traditional 24-hour format. However, this trend is expected to reverse in the near future.
This is what two scientists, Matt King (Director of the Australian Centre of Excellence for Antarctic Science (ACEAS) and Professor at the School of Geography, Planning and Spatial Sciences at the University of Tasmania, Australia) and Christophe Watson (Professor at the Astrophysical Research Centre at Queen’s University in Belfast, UK), wrote in a recent article published in The Conversation.
Earth’s Days Show Unpredictable “Flexibility” – (Image: NASA)
According to the two professors, despite the records and trends of increasing rotation speed over the decades, since 2020, Earth’s rotation has strangely slowed down.
The cause remains a mystery. The current speed is still above average, leading to the aforementioned shortest day; however, if this trend continues, we may soon reach a point where a day exceeds 24 hours.
Researchers suggest that tidal friction—mechanisms controlled by the Moon—has caused Earth to slow down. This process adds approximately 2.3 milliseconds to the length of each day every century. Billions of years ago, a day on Earth was only 24 hours long.
But over the past 20,000 years, another process has caused an unusual acceleration of Earth, believed to be due to melting ice sheets at the poles after the last ice age, which reduced surface pressure and caused the crust to shift toward the poles.
At that time, the planet acted like a dancer pulling its limbs closer to its body and accelerating, shortening each day by about 0.6 milliseconds every century.
There are many other processes in planetary evolution that can change the length of a day; thus, Earth—like every other planet in the universe—does not have a fixed day length but changes over time.
Of course, this will not significantly affect your clock, as human life is too short to clearly perceive this variation, especially when one only witnesses fluctuations in the millisecond range throughout their lifetime.
It wasn’t until 1960, when humanity invented radio telescopes to simultaneously observe celestial objects, that astronomical measurements allowed for the indirect calculation of a day on Earth, making it possible to recognize that a day could lengthen or shorten.
This will not impact daily life significantly, except for slight changes that might require sophisticated adjustments in GPS systems and other technologies that influence modern life over a long period.
