Statistics of Saturn's spokes

Images of Saturn's B ring were used to analyze the spoke phenomenon. The position of spoke edges was measured for 150 different spokes on up to five subsequent images each. Spoke edges move in a manner similar to Keplerian orbital velocity. A rough model of the spoke visibility was constructed as a function of the spoke age and this was fitted to the observations. Results indicate an active time for spoke visibility increase, that spoke decay takes place faster than spoke growth does and that trailing edges vary little during the lifetime of a spoke.