In Six Easy Pieces: Fundamentals of Physics by Feynman, the claim is made that the reason why electrons don't just collide “ontop” of the nucleus is due to the Heisenberg uncertainty principle. This perplexes me greatly; it sounds wrong to me. The moon and the Earth do not collide because there is a balance between the kinetic energy “pushing” outward and the gravitational attraction “pulling” inward. Although electrons are not classical objects, I don't see why the same analogy does not hold, albeit a need for modification to be framed in terms of the Schrodinger equation. An electron in hydrogen might start off far away, “feels” the Coulombic potential, and its position is altered until a balance is met between the attraction bringing it closer in and the speed directing it away, resulting in some bound state. How does the physical cartoon we have about planets fail to describe electron/nucleus interaction? I don't see that the cartoon is fundamentally different. This is my first question. The answer to my first question may lie in my 2nd question. I have taken a year of graduate non-relativistic quantum mechanics; perhaps I need more to understand the answer to the question I am getting to. If so, and an answer is only possible in a QFT framework, just let me know. My 2nd question concerns how the Heisenberg uncertainty principle relates to an increase in energy based on knowing a position. For example, I have heard the statement that one can attribute the notion of zero-point energy in a harmonic oscillator as consequence of specifying its position; that somehow the Heisenberg uncertainty principle also states that if a position is specified, there MUST be an increase in the kinetic energy. I do not understand this at all. My only understanding of the Heisenberg uncertainty principle is that, at certain scales, the meaningfulness of certain conjugate variables diminishes. One cannot talk about the position and momentum simultaneously beyond a certain uncertainty window. That is, in my mind, very different from saying that because we can't know the value of a quantity, it must be big in overall value, whatever it is.