"What is marriage, exactly, and how could we explain it to an alien anthropologist? It's more than just a living arrangement. Is it an endeavor, a pledge, a symbol, or an affirmation? Is it a span of shared years and shared experiences? A vessel for intimacy? Or does the old joke nail it best? 'If love is an enchanted dream, then marriage is an alarm clock.' " Mostly male laughter in the congregation is shushed. "Maybe marriage is difficult to define because of its array of shapes and sizes. Marriage differs between cultures, tribes, centuries, decades even, generations, and--our alien researcher might add--planets. Marriages can be dynastic, common-law, secret, shotgun, arranged, or, as is the case with Sharon and Peter"--she beams at the bride in her dress and the groom in his morning suit--"brought into being by love and respect. Any given marriage can--and will--go through rocky patches and calmer periods. Even within a single day, a marriage can be stormy in the morning, yet by evening turn calm and blue ..."