Hello, My question is fairly simple. My instructor solved in class today Laplace's equation in spherical coordinates which resulted in spherical harmonics. I have not taken any quantum mechanics yet so this is my first exposure to spherical harmonics. What do the "l" and "m" terms in the expressions correspond to exactly in physical reality? I'm under the impression that l = 0--> monopole, l = 1 --> dipole, etc. But what are the "m" terms for? And how exactly do I use these crazy formulas to find the multipole moments for arbitrary charge distributions?