Melancholia opens with a wedding. You think, maybe (considering the title), it’s terse drama about a marriage circling the drain. Kind of like Revolutionary Road. But it’s a little bit more like Armageddon. With a little bit of Phenomenon. Kirsten Dunst and Alexander Skarsgard conclude their matrimonials with the observation of a planet that has been “hiding behind the sun,” now entirely, and ominously, visible to the eye. Strange things begin to happen. People freak out. Little kids say scary things. And marriages circle the drain? Yes. They sure do.