Ever since the Earth was formed about 4.6 billion years ago, it has been rotating non-stop on its axis. While the rotation of the Earth is the reason why sunrises and sunsets happen, many people are unaware as to why the Earth rotates at all, or what would happen if our planet were to suddenly stop spinning one day.
The Earth’s rotation
The first thing to understand is that almost every object that exists in space rotates in some form or other. The planets rotate, the Sun rotates, the asteroids rotate, solar systems rotate, and so on. Even pulsars, which are known as the fastest things in the universe, rotate at an estimated speed of 716 times per second.
To understand why the Earth rotates, you have to dig deep into the history of the planet and its formation. When the sun was born, some of the material that remained after the process went about circling the star.
The gas, rock, and dust that was whirling around the Sun slowly started colliding with each other and eventually morphed into what we now know as the Earth. During its formation, the continuous collision of rocks on the young Earth sent it spinning in one direction. And our planet has been spinning ever since.
However, the rotation of the Earth has been slowing down over the past several millennia. A study of eclipses showed that the planet’s rotation slowed down by around 6 hours over the past 2,740 years.
Another study found that the Earth slowed down for a period of five years every 25-30 years, after which it resumed its normal speed. Interestingly, data suggests that the number of earthquakes spikes during this five year period. However: “Over long enough times, the Moon is the only dominant factor in slowing down the spinning Earth, as our 24-hour day is relatively recent, and won’t be around forever,” says a Forbes article.
If the Earth stopped rotating
With the speed of rotation slowing down, scientists have wondered about the possibility of an Earth that does not rotate. Such a scenario would mean that one face of the planet would be constantly exposed to the hot sun while the other half would be faced with the coldness of space. Large areas of the planet would become inhospitable due to several geographic changes.
“If the Earth were to stop spinning on its axis, gradually the oceans would migrate towards the poles from the equator. At first, only small regions of terra firma around the equator would rise out of the retreating waters. Eventually, there would be a huge mega-continent wrapped continuously around the Earth at the equator,” says an article published by ABC.
The bulk of the water that moves away from the equator would settle on both the poles. Eventually, the Earth would have a single continuous landmass around the equator and two vast polar oceans on both sides. A large part of the current land mass, including areas like Canada, Greenland, Europe, and Asia, would be underwater.
Even though the consequences would certainly be devastating, there is nothing to fear as of now since the Earth will not suddenly stop spinning one fine day. It will take billions of years for the Earth to stop rotating. And this slowing down of the Earth’s rotation is the reason why the scientific community adds an extra second to the length of a day every 500 days.
Why does the Sun rotate? What caused the rotation of the bodies in the universe in the first place? Now, that’s a question for another time.