In response to:
ScientificBlogging Gamma-ray photon race ends in dead heat; Einstein wins this round. We'll get you yet, though, Al.
Space/Time can't be that "frothy" since the laws of the universe are so precise. Too much looseness and the whole thing falls apart.
The point is that there are viable and very precise theories - "laws of the universe" - that separately either hypothesize or predict a "frothy" universe on a scale somewhere between 10-18m and the Planck scale (10-35m). The observations discussed put presumably very tight constraints on the free parameters in the theories that distinguish them from Einsteinian General Relativity.
Even Einstein's very beautiful, very precise etc etc General Theory of Relativity CANNOT rule out frothiness of the universe on some heretofore unobserved, untested scale, though very good arguments can be made that the GTR will break down at some scale > Planck. If frothiness is observed at some larger scale, it will put a lower bound on the domain of applicability of the GTR (Since it hypothesizes a smooth (or at least twice differentiable) geometry for spacetime, GTR is valid above but not below the scale at which those “violations” are observed.).