Wow! This video compilation, shot from the International Space Station is stunning. It shows the Earth at night and features the lit cities of the world, countless lightning storms and a stunning aurora (I've just learned in my physics course why the aurora is usually green - it's the oxygen in the atmosphere that makes it so). What surprised me is that, for once, I didn't frown and tut to see all the man-made illumination. Firstly, it was simply beautiful; also, the natural light effects seemed even more powerful and dramatic, if more short-lived. But chiefly, I found it rather thrilling and at the same time comforting to see all those twinkly lights. It was like passing along a street at night before people close their curtains. How comforting to see all those illuminated interiors, to see all that life carrying on. All of a sudden, I could imagine what it will be like when we start to investigate other planets. How lonely to approach an entire planet lying in complete darkness! How exciting to see the lights on!