The Earth is currently moving around the Sun at around 107,000 kilometers per hour (66,500 miles per hour), while the Sun hurtles through the galaxy at 828,000 kilometers per hour (514,500 miles per hour).
We know this through centuries of observing the planets and the stars, and observing their motion relative to our planet. You see evidence of the Earth’s spin constantly, as the Sun and stars move across the sky as we rotate like a gigantic kebab. If you’re willing to put the effort in, you could also observe nearby stars apparently changing position in the sky (known as ) throughout the year, gathering your own evidence of Earth’s orbit around the Sun. You could also observe stellar aberration, building a case for the model of the Solar System we figured out centuries ago.
But, of course, there are people out there on the planet who don’t believe this is true. In a by one confused individual, they post the Earth’s movement through the Solar System and galaxy, and the fact that we can still do things like tightrope walks and , as “proof” that the model is incorrect.
This is, of course, a hot mess of a post that demonstrates a profound misunderstanding of physics. The idea appears to be that the fact that we don’t feel the planet hurtling through the galaxy somehow proves that the planet is stationary.
In fact, the reason why we don’t feel the Earth move at breakneck (and everything else) speeds is because there is no such thing as an absolute frame of reference in the universe. When not accelerating or decelerating, you are at rest, whether you are hurtling along on Earth, on a rocket heading away from Earth, or slowly orbiting the solar system on Planet 9 ().
A body at rest , while a body in motion remains in motion until another force acts upon it, known as inertia. This is the state you are in as you travel on the Earth. The Earth’s motion is relatively smooth, though it is slowed and sped up by various factors, including . If it were more jerky, you would feel the acceleration and deceleration (from forces being applied to the Earth) but you do not feel or inertia.
Think about when you are in an airplane. When the vehicle begins to accelerate, you feel this force being applied to you via the chair behind and beneath you. But once the aircraft stops accelerating and achieves a constant speed, your frame of reference is at rest, and you feel as stationary as if you were on the Earth (which, remember, is actually hurtling through the universe).
The rocks of the above post are not immune from the laws of motion and inertia. They continue on the path they are set on (in this case, being a cute little stack following the motion of the Earth) until a force (some jerk knocking them over) is applied to them. As well as not having to worry about the motion of the Earth throughout the galaxy (only his frame of reference), the tightrope walker in the post (Philippe Petit) also benefits from the Earth dragging along with it through frictional forces.
While a stationary Earth would explain why the rocks do not fall over, it would not explain many of the other things (such as parallax of the stars) that we have observed, nor be able to make predictions about the movement of the bodies in the universe – which is why we abandoned that model centuries before the meme was made.