Why Are Cold Stars Red and Hot Stars Blue

Why are cold stars red and hot stars blue? I asked Sherry, ma chéri, whilst stargazing yesternight she and I, only us, hands holding; Why are hot stars blue and cold stars red? I asked her anew 'cause I thought she knew; Her mouth motionless–her eyne tears shed. Why are blue stars hot and red stars cold? She kept on weeping, still voicing no reply; Barefoot, as usual–her feet gladly I behold. Why are red stars cold and blue stars hot? No answer but an osculation was all I got. Lying on the grass yesternight, she and I, Rainwater started pouring over the lass And me, yesternight, lying on the grass.