Is an electron moving around a nucleus in absolute motion from the perspective of an observer?

Question

Does this question in the title have any sense or not? Am I asking a good question?

Answer 1

This is not quite a good question; I will try to explain why for you.

First, an electron does not "orbit" a nucleus in the same sense that a planet orbits the sun. If it did, then it would radiate electromagnetic energy away and rapidly fall inwards to the nucleus. We can only talk about the probability of finding the electron in one particular area of space from one moment to the next; between those moments it is impossible to say anything about the particular trajectory it followed between those moments as it passed through point A on its way to point B.

This means its "state of motion" while occupying a certain orbital in the vicinity of a nucleus is ill-defined from the standpoint of classical mechanics, where we can predict orbits with well-defined radii and figure out the actual path followed by (for example) a moon belonging to a planet as it moves around.

This is a complicated business and provided the initial motivation for the invention of quantum mechanics, starting with the work of Niels Bohr and others, and I invite the experts here to help explain to you more about the the basics.