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VIVA – Recently, there has been a phenomenon that reveals the day suddenly getting longer. Meanwhile, scientists do not know why.
As quoted from the Sciencealert website on Wednesday, August 10, 2022, the Earth's rotation rate is very significant for navigation systems such as GPS that cannot operate without its presence.
Over the last few decades, it has been the rotation of the earth around its axis that determines how long the day is indeed moving faster. This trend has made our days shorter.
In fact, as of June 2022, the shortest days have been recorded for the last half century or so. Although Earth reached its shortest day on June 29, 2022, its long-term trajectory appears to have shifted from shortening to lengthening since 2020.
While the clocks in pur phones indicate 24 hours in a day, the actual time, it takes for Earth to complete a single rotation varies ever so slightly. These changes occur over periods of millions of years to almost instantly.
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- Pixabay/Steven Goddard
An ever-changing planet for millions of years, Earth's rotation has slowed due to the frictional effects associated with the tides driven by the Moon. That process adds about 2.3 milliseconds to the length of each day of each century. A few billion years ago, Earth’s Day was only about 19 hours.
Meanwhile, over the last 20,000 years, other processes have also worked in the opposite direction, accelerating the Earth's rotation.
Today, our planet's rotational speed increases as this mantle mass moves closer to Earth's axis and this process shortens each day by about 0.6 milliseconds every century.
In addition, weather and climate also have an important impact on Earth's rotation causing variations in both directions. Every two weeks and monthly get cycles move mass around the planet, causing day length changes of up to one millisecond in both directions.
Although the reason is still not quite clear, scientists have recently speculated that this mysterious change in the planet's rotational speed is related to a phenomenon called the "Chandler wobble" or a small deviation in the Earth's axis of rotation with a period of about 430 days.
Observations from radio telescopes also show that the wobble has decreased in recent years and the two can be linked.
In addition, there’s also one other possibility that is quite plausible, that nothing specific has changed on or around Earth. It is possible that long-term tidal effects act in parallel with other periodic processes to produce temporary changes in the Earth's rotational rate.
