Understanding atoms.

[Purple Rabbit]

As for the proton looking like a planet- I doubt it. The atom used to be represented as a ball, but now we know it is mostly empty space. I do believe that the proton is very much the same. It is comprised of 3 smaller parts, so definately won't resemble a sphere.

Before string theory elementary particles like the electron, the gluon and the quark where considered to be point particles, i.e. particles with no spatial extension. String theory proposes stringlike inner structure for elementary particles. But don't think of strings as really elastic bands. It's just a model people need to visualize, that more or less fits the mathematical model of these stringlike things.