system
Given the following post, respond as if you're commenting on Reddit:
human
Is the distance between atoms in a molecule like hydrogen gas constant? If yes, how is it kept constant?

I read in a high school chemistry textbook that the distance between the protons of a H2 (hydrogen-gas) molecule is constant. It didn't explain why. 
It confuses me, as I always thought, since the electrons are constantly moving the coloumbic force on the nuclei should force like a tandem motion. 
At least it's what I always imagined that they all hold each other in place like they're connected by jelly strings.
gpt
The truth is that they don’t have well-defined positions, because they’re quantum systems. But you can imagine in a classical version of a molecule, that the two atomic nuclei could vibrate around their equilibrium position. There are vibrational excitations of molecules, and they can be described quantum-mechanically.