Is the asteroid at the front a part of the background image or is it added in? It blends well.
The asteroid in the foreground is not part of the background image, and is, in fact, two halves of different asteroids that I had to fuse together to make one asteroid =P
The foreground asteroid was created by taking the left and right asteroids in this image, which are only partial asteroids (part of the asteroids are cut off by the edge of the picture), and cutting them out / combining them to make a single asteroid for the foreground: http://i28.tinypic.com/2yx3ul0.jpg