Let $G$ be a compact Lie group. What can we say about subgroups of $G$ isomorphic to $Z_n$? For example, $G$ is $SU(2)$, or $SO(3)$ and $n$ is $2$ or $3$ and so on.
A naive idea is that if $x\in G$ is the image of the generator, then such subgroups are in one to one correspondence with the solution of equation $x^3=1$. What can we say about this equation? Are there solutions? how many? how to parametrize if there is a smooth family?