system
Given the following post, respond as if you're commenting on Reddit:
human
If at absolute zero all motion stops, does that include the orbit of electrons around the nucleus of an atom?
gpt
Firstly, electrons do not 'orbit' in the way that a planet orbits a star. At the level of quantum physics particles exist in one of a set of distinct 'states'. For electrons in an atom, these states are usually defined by energy and angular momentum, instead of position. Heisenberg's uncertainty principle says that we cannot measure position and momentum with 100% accuracy at the same time. So an electron's 'orbit' is really the region where the electron is likely to be found, and is rarely shaped like a circle.

Absolute zero temperature means that *kinetic* energy vanishes, but there are other forms of energy. For an electron in an atom, there is energy that binds it to the nucleus due to the electric force between it and the protons. Even if there is no temperature and the electron is as closely bound to the protons as possible, it still has some energy.

Also, temperature is a large-scale idea (thermodynamics), and at the scale of single particles, things can still move without having temperature. We need a different theory to explain what goes on there (quantum mechanics).