The magnetic pull of the sun and other planets, including our moon has influences upon this core rotation. The pressure of the water of oceans and land masses create factors influencing the core. Earth quakes and shifting plates of the earth, volcanic eruptions all play a part. There is a theory that the alignment with the center of the galaxy is one possible explanation, though not totally supported by all scientists and those who study the astronomy. It is establish fact that planets influence others and are all attracted in their rotation about the sun, just as in other solar systems in the galaxy. A simple example is the moons pull and effects on the tides every day. The gravitational pull causes the movement of the water levels and tides to move out and back in an a never ending cycle of activity and will do so for eons to come.Scientists also maintain that with the melting of glaciers and ice on the planet, the added pressures on the sub strata, cause more and more violent earth quake activity, which we have been experiencing lately. It is hard to differentiate the extent to which there is man made causes from pollution, poor conservation habits, and wrongdoing by human activity and what is all just one big cycle and may occur naturally,despite what we humans do or think. I believe that we can affect many things about our habitat, but not the core, which is influenced by magnetic anomalies that we have no control over.