The background in this image is actually a reflective sphere bouncing the lights back in on to the smaller sphere in the center. I love the Blender Cycles render engine.
I should probably have posted this back on May 23rd when I made it, but I couldn’t think of a way to reduce the file size to less than 1MB for Tumblr while maintaining enough quality until today. I had to cut the number of frames in half and apply a temporal offset to the animation, screening a copy of the video layer on to itself to fit all of the frames in. I think the original is better, but I can’t post that here.