It's Official: We Were WRONG About the Big Bang

While I definitely found this a great discussion, to me, it failed to reveal the true nature of the expansion and why it's not necessary for the Universe to be actually expanding into anything.  The expansion of the Universe, as I understand, is a relative phenomenon that is created not so much by an actual expansion but rather by the increasing of a scale factor a(t) in the definition of distances.  Essentially, space-time is "expanding" because the measurement of distances between two points in space-time is increasing due to this scale factor.  Say we have a ruler, and the edges of the ruler never move; however, the definition of how much distance the ruler represents continuously increases over time.  So, when we measure distances with our ruler, the region subtended by the two ends of our ruler measure a continuously increasing distance.  Since the laws of physics are parameterized by this distance measurement, we will observe phenomenon that is consistent with objects being forced further and further apart, even though they may not actually be moving.

So, as I understand it, the Universe is not expanding in the real sense that we think of expansion (that is, the cartoons of the expanding balloon or the expanding loaf of bread with raisins are mis-representations).  Rather, what is happening is that the definition of the measurement of distances between two points is increasing (while the balloon or the loaf actually remain static in their extent), and the Universe and physical phenomenon within it are simply responding consistently with that fact because the laws of physics only operate on the dynamic, measured relative distances, not the static, underlying coordinates.