If you like cosmology as much as I do, then you would probably like to have something cosmetic moving around your screen!
Asteroids 3D live wallpaper is free and after you install it you can use it’s customization to change it to your convenience. It gives you a number of different backgrounds. You can also change the number and the speed of your asteroids. It,optionally, uses your gyroscope so that when you move your device, Asteroids 3D live wallpaper also moves with it! Try it for fun 🙂