Why Is Earth Suddenly Spinning Faster?

On July 26, 2022, scientists announced that the Earth experienced its shortest day on record, with that particular day being 1.5 milliseconds faster than on average. We are used to measuring each day as a set 24 hours, yet this is merely for simplicity. In fact, every day is a slightly different length, although the difference in length is usually so minuscule that it goes unnoticed. However, over the last few years, the Earth has begun spinning faster. This trend has resulted in scientists recording shorter days. Stranger still is the fact that they do not know precisely why this is occurring. 

Measuring Time

Atomic clock CS-3 based on cesium in Germany
Atomic clock CS-3 based on cesium in Germany

Most of us likely measure the flow of time with clocks on phones or other devices. Although these methods serve us well in our everyday lives, they are wildly inaccurate in measuring the accurate flow of time. If you want to measure the true flow of time, you must use what’s called an atomic clock. Atomic clocks are the most accurate clocks ever used. An atomic clock uses the radioactive decay of particular elements, which decay at constant rates that can be measured. Thus, atomic clocks can measure time down to its smallest units. By comparing atomic clocks to the speed at which the Earth rotates, scientists can see if the Earth is spinning slower or faster. 

Possible Explanations

The fact that the Earth is spinning faster should be no cause for alarm. After all, it only adds a few milliseconds each year, which itself has no impact on our everyday lives. The speed of Earth’s rotation has never been a constant factor in our world. Dozens of factors influence the Earth’s orbit, such as the interaction with the moon, sun, and planets. The density and speed of our atmosphere, as well as interactions between the Earth’s crust and interior, can all change how fast our planet spins. In fact, throughout many millions of years, the Earth’s rotation is actually slowing down. When the dinosaurs walked on Earth over 65 million years ago, days were over an hour shorter than they are today. This is mostly caused by the fact that the moon is slowly moving away from us, causing the Earth’s rotation to slow down. 

The currently measured increases in Earth’s rotational speed are a mystery. As of yet, scientists do not quite understand what’s causing it, yet there are some proposed explanations. One such explanation has to do with what’s called the Chandler Wobble. The Chandler Wobble is a phenomenon by which the Earth wobbles ever so slightly about its axis. Interestingly, starting in 2017, the Chandler Wobble suddenly disappeared, which could explain why the Earth has experienced a faster rotation since that time. There are a number of other possible factors as well. The speed of the atmosphere could also be the culprit. Or perhaps something is going on in the Earth’s mantle and core, which could also be increasing the Earth’s speed. The Earth is indeed a mysterious world, and as more short days are measured, we may have an explanation for why Earth is suddenly spinning faster. 

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