Ok, this one bugs me a little bit. Nothing in this image is moving. It's your brain hallucinating. Really. See how wherever you look, everything is still, but in your peripheral vision its moving? Now look somewhere else in the image... that part seems to stop moving and other parts will appear to start moving. If I stare really hard and don't move for a few seconds I can get it to stop moving, but its only for a second.
There are many examples of this optical illusion called "anomalous motion." I've included a few more below and you can find some others good ones here. Remember, none of these are actually moving. One person goes into some depth about why these illusions exist here. Apparently it is still a matter of some debate, however, it is related to the voluntary and involuntary motions of your eyes and the process our brain uses to keep us looking at a specific point in space. Certain images cause the involuntary movements to sort of cause your visual system to drift and then your brian tries refix your gaze. The constant adjustment is somewhat consistent with what your brain has to do when objects in your visual field are moving, so your brain assumes that something like that is why it needs to readjust. So your brain triggers the messages that tell you that you are detecting motion. Because it is keeping the center fixed, it doesn't interpret that as moving... its only the parts you aren't focused on that move.
Your brain perceives motion in strange ways. Watch this video to see how it incorrectly interprets actual motion.