Paper: Inner core backtracking by seismic waveform change reversals (11 points, 21 days ago) https://news.ycombinator.com/item?id=40679957
I wonder if that has any effect on the periodic flipping of the north and south magnetic poles. Something has to cause that to happen.
Moving backward in the rotating reference frame of the Earth. In other words, it's rotating slightly more slowly than the Earth as a whole.