Suppose we have a bunch of electrons, held together by an electromagnetic field (magnetic bottle kind of thing). Suppose this bunch is large enough to view with the naked eye (say, like a water droplet). Would it be visible? If so, what would it look like, and what mechanism makes this happen? Atoms can send out light when electrons jump to a lower energy level. I don't suppose a bunch of sole electrons has this behavior..? Of course, they can be protons, positrons for that matter. The reason I'm asking is because of the Angels & Demons movie... They supposedly have a bunch of positrons in a magnetic bottle in the movie, large enough for the naked eye to see. And it looks like a blue fire ball... That doesn't seem very realistic to me. But when a friend asked me what it WOULD look like in real life, I found I had no answer... Thanks!