This is not an educated guess. Filtering of civilian GPS can be used to back these displacements out. See the comments under: http://news.ycombinator.com/ite

This is not an educated guess. Filtering of civilian GPS can be used to back these displacements out. See the comments under: http://news.ycombinator.com/item?id=2315839 http://news.ycombinator.com/item?id=2315839 The history of science is full of instances of precise measurements uncovering new phenomena by ruling out all known explanations. So it's important to understand these changes in day length (mass distribution, really). These calculations are actually being done on a regular basis, someone just decided to make a press release out of this jump because of the obvious interest.