I think I more or less understand how a gyroscope precesses--at least mathematically and in terms of torque/angular momentum. My question here is: how does the gyroscope start precessing in the first place? The external forces on the center of mass are entirely vertical. Given that Newton's Second Law should always work, I don't see how there would not need to be an *external* force in the *horizontal* direction to get the COM initially moving in that direction. Obviously this means I am mis-understanding something. Does anyone have a good explanation of how this works and why I am wrong? Thank you!