system
Given the following post, respond as if you're commenting on Reddit:
human
Why don't electrons run out of energy ?

Q1. Electrons are always pictured as spinning around the nucleus. How can they keep doing that forever and ever even if no interaction takes place ? Doesn't the kinetic energy eventually run out ?

Q2. If you take one atom of hydrogen and you cool it down and put it in a vacuum, is the speed of its electron slower/faster than if the atom is "hotter" and in a dense liquid ? aka, is there a drag effect on the electron depending on the medium it's in ?
gpt
1.  Moving forever doesn't mean you are using energy.  The Earth circles the sun without slowing down appreciably.

Traditional electromagnetic theory predicts that a moving electrical charge will generate an electromagnetic field and decay.  However, this does not occur and was always considered a flaw in EM theory.  Quantum theory solved this, by requiring specific states.  An electron can only decay from one quantum state to another, and every time that happens, a photon is emitted.  

2.  The electron circles the nucleus based on the electrical force, so it wouldn't slow down or speed up depending on medium.  And there is no "drag" at the subatomic level... there can't be any liquid molecules in between the nucleus and electron, so there is no effect there.