# Why do photons have spin of 1 when they have no mass? [duplicate]

How can a photon have a spin of $$1$$ when it has no mass? Since the spin is intrinsic angular momentum, if $$m = 0$$, then the spin must be zero.

A classical picture of spin angular momentum treats particles like tops, and says that their spin is given by some form of $$I\,\omega$$, where $$I$$ is derivable from the objects' geometry and mass, and $$\omega$$ is its angular velocity.
For quantum mechanics, this picture does not work, at least when describing spin angular momentum. Even for the electron, it if you try and work out some boundaries on what $$I$$ can be from experiments about the size of the electron, you get implausible values for the angular velocity.