The physics involved isn’t difficult to understand.

Physics mostly starts with physical experiences. Though at times the experiences can involve complex instruments, fundamentally physics is a field of scholarship built on experiments that people can perform in their own physical lives. These physical experiences are explained via mathematics, when possible. If a mathematical explanation is not available, the result is considered “empirical”. It means physicists know this happens, but don’t understand why.

In the case of Polar Vortex, there is a certain physical experience that is relevant. If you have ever put your hand outside the window in a moving vehicle, you have experienced wind blowing past your hand. This happens even if the air outside is standing still.

This is called “relative” velocity. Even though the air outside may be still, the movement of the car or other vehicle makes it seem as if the air is moving. In reality, it is you who is moving, not the air.

This can be handled with mathematics. The mathematics involved is called “vector addition”. The mathematics doesn’t actually depend on whether you or the air is moving, it works either way. To keep the physics straight through the math of vector addition, YOU have to keep track of what is moving, what is still.

This effect happens with the moving Earth. The Earth is actually like a vehicle on which we are existing. The vehicle is not still, it is moving.

One of its movement is a rotation about its axis, the day-night cycle.

This movement, just like the movement of your car, gets vector-added to air which might be moving North-South. This is slightly complex vector addition, because the Earth is sphere-shaped. The point is that just like your car can change its speed, the East-West speed of the ground beneath your feet actually changes as you walk from Equators to Poles. So the vector-addition would have varying East-West component from Equators to Poles.

So, anyway, this vector-addition causes North-South winds to acquire an East-West component. Just like the vehicle moving through air.

Since we are doing physics, it is up to us to remember through the math that the North-South component is coming from actual air movement due to whatever reasons. But the East-West component is not part of the air movement, it is due to Earth’s rotation.

This vector-addition has been given a name upon the first person who explained it. It is called the Coriolis Effect. It has math associated with it.

Polar Vortex scientists were able to use the Coriolis Effect math, to empirically match the Polar Vortex behavior. They would have had to set the North-Side component to zero to do this empirical match.

However, somewhere along the way, it seems understanding of the vector-addition nature of the Coriolis Effect had been lost somehow. People have been writing as if it is some kind of mysterious force.

It is not. Coriolis Effect is not any kind of mysterious force. It is just the name given to vector addition of this particular kind.

When I saw this item of information – that the Polar Vortex is explainable by Coriolis Effect, it told me that since the North-South component has been set to zero, that means the air is not moving at all. Remember that Coriolis Effect is about air that is moving North-South. It only appears to have an East-West component, but that component is coming from the moving Earth.

So, in the case of Polar Vortex, the obvious physics interpretation of the math was that the air is trying to sit still due to inertia, all the motion is apparent and is coming from the East-West component, the Earth’s rotation.

In other words, the Polar Vortex is air sitting still, but the Earth is spinning under it. Of course it gets complicated after that, but that’s the fundamental physics. Polar Vortex is not spinning; it only looks that way. In reality, the Earth is spinning under it.