We all have them: nights when you're lying in bed worrying about what's happened or what's to come. I remember one when - after I said my prayers - I felt an odd comfort knowing there was a huge universe whirling above me. I wasn't in control and never really would be. And it was all right. I had a warm bed. I had everything I really needed. It was a blessing to be small in the world and know there were comets and stars, clouds and astonishing mysteries, all turning above me. There is so much of the world we don't really see, but it's no less real.