We've barely made it to the year 2021, and there are already claims that the next 365 days will "fly by" because the Earth is spinning faster than usual.
A series of articles were published this week warning of shorter days and our planet acting out of character.
However, the Earth periodically speeds up and slows down during its rotation around its axis.
So while the Earth has been a little speedier in the past few years, scientists say that it's business as usual for our home planet.
How fast does the Earth rotate?
Aside from orbiting around the Sun in approximately 365 days, the Earth also spins around its own axis.
After the planets of the Solar System were formed from clouds of gas and dust around 4 billion years ago, the Sun's gravitational orbit placed them under a lifetime of spinning. As the material that formed the planets came together, Earth and its planetary companions began spinning faster and faster.
A classic example often given to illustrate the spinning of the planets is that of a figure skater who brings their arms closer to their body in order to increase the speed of their rotation.
On average, the Earth completes one full rotation around its axis in about 23 hours, 56 minutes, and 4.09053 seconds at a speed of roughly 1,000 miles per hour.
However, there are a number of factors that affect the speed of Earth's rotation periodically, whether slowing it down or speeding it up.
Is the Earth spinning faster?
Well, yes, but there's no need to worry. Here's why.
In the past few years, the Earth has been spinning at a higher speed than before. However, the difference in the time it has subtracted from our days is not significant enough for us to notice.
James O’Donoghue, a planetary scientist at Japan Aerospace Exploration Agency, can confirm that during the year 2020, the Earth was relatively stable.
"The amount of deviation is extraordinarily small in 2020-2021," O'Donoghue tells Inverse. "Earth's day length throughout 2020 changed by 0.00127 seconds, or 1.27 millisecond, compared to previous years which were in the hundreds of milliseconds."
Therefore, claims that the Earth is spinning at an unusually faster rate are incorrect, and how much it has affected the length of our days is exaggerated.
Why does the Earth's rotation speed change?
There are a number of factors that affect the speed of Earth's rotation around its axis.
- The Moon's gravitational pull
- Wind speeds
- Movement in the Earth's core
- Atmospheric pressure
- The melting of the ice glaciers
Mathieu Dumberry, a professor at the University of Alberta's department of physics, explains how there are all these competing forces that cause the Earth to speed up and slow down periodically.
"There is really a collection of different processes that create changes in the Earth’s rotation, and all are happening at different timescales," he tells Inverse. "But it's not something we can notice and detect."
"It's not something we can notice and detect."
As an example, the speed of winds changes depending on the season, creating a force that either accelerates or slows down the planet as it tries to conserve its angular momentum while spinning.
Meanwhile, the Moon's gravitational tug, which causes high and low tides on Earth, also has an effect on the planet's spinning speed.
Aside from these external forces, the planet itself can impact how fast it rotates around its axis. When the Earth was in its infancy, there were huge ice sheets covered most of North America, Eurasia, and South America during the Pleistocene era.
However, as these ice sheets melted, the shape of the planet slightly changed, and parts of the Earth were pushed down. As a result, the rotation of the planet has to adjust to its new shape, speeding up in its rotation as mass is taken away from the equator and redistributed to the poles instead.
However, that part of the Earth is slowly coming back up. As the ice sheets melt in places such as Antartica, leading to an increase in sea level rise, essentially having the reverse effect and thereby decreasing the speed of Earth's rotation, according to Dumberry.
"It's only a temporary effect," Dumberry says. "Over time, these changes average out."
For the past 60 to 70 years, these factors have led to a trend of the Earth speeding up in its rotation. However, that does not mean that this trend will continue until our days fly by with fewer hours.
"It’s much easier to look at a trend and make an extrapolation," Dumberry says. "However, It’s good to know the physical phenomenon that’s causing these changes, and look at the data over a longer period of time."
If we were to look at the data of the Earth's spinning speed over a long period of time, we would see that the rotation of the planet slightly increases or decreases in speed periodically, and the changes are too small for it to have an effect on our day to day life.
"It’s not a manifestation of any change that’s going on, it’s basically physics 101," Dumberry says.