I thought I would wish everyone a happy Earth Day. The music in the video above is by Mike Oldfield, whose album The Songs of Distant Earth is taken from a novel by Arthur C. Clarke. Science fiction plays a particularly useful role in getting us to think about the environment, as it makes us imagine futures in which we ruin our Earth, futures in which we make do in less hospitable environments here and/or on other planets. For now, at least, Earth is the only home we have. And even if we manage to spread to other worlds, unless we have already learned how to care for this one, chances are we will ruin the worlds we spread to, too. That story has also been told on more than one occasion in science fiction.