Bodies contained in these objects are analogized to cars moving through a traffic jam in a common (-5[1])explanation of a theory resolving their “winding problem.” Lin (10[1])and Shu’s density wave (10[1])theory describes these objects, (10[3]-5[1])which contain (10[1])the majority of HII (“H two”) regions. (-5[2])The intrinsic luminosity (10[1]-5[1])of these objects is proportional (-5[2])to their (-5[1])asymptotic (-5[1])rotation (10[1]-5[2])velocity (10[2]-5[3])by the Tully-Fisher (-5[1])relation. (10[4]-5[4])Both (10[2])prongs (10[1]-5[1])of Hubble’s (10[1])“tuning fork” (10[1]-5[1])diagram (10[3])contain these (10[1]-5[1])objects, (10[4]-5[2])some (10[1]-5[1])of which (-5[1])are barred. (10[7]-5[1])The (10[1])central (10[1])bulges (10[3]-5[1])of (-5[1])these objects (10[2])contain (10[3]-5[2])supermassive black (10[1])holes. (10[20]-5[8])For 10 (10[1]0[1])points, (10[3]-5[1])name these (-5[1])disk-shaped (10[2]-5[2])systems (10[1]-5[1])of stars, (10[1])gas, (10[2]0[1])and dark matter, (0[1])exemplified (10[3])by Andromeda (10[1])and the Milky Way. (10[1])■END■ (10[22]0[11])