thebuzzard If we, in fact, are basing a reference and framework on our earth - marked by a previous belief that the earth's inner core would indefinitely rotate relative to the "gravitational core–mantle coupling" & "under the effects of the geodynamo" - what will be the result of its "pause" and potential reversal in direction? As the authors note, several characteristic changes have already occurred (e.g. length of day & magnetic field) and are significant. Will this observation necessarily change our already established "science?"
No it will not. Here are some facts to consider:
• Theoretically, the laws of physics have been formulated with respect to an "inertial frame of reference" (i.e. one that does not accelerate or rotate), and have no explicit dependency to our position on Earth, which is dynamic in any case. Newton adopted this approach for classical mechanics, Maxwell for electromagnetic theory and even Einstein for relativity.
• Practically, nevertheless, we inhabit a world that is non-inertial, and this manifests itself in centrifugal/Coriolis forces whose consequences we can explicitly observe (e.g. the Coriolis effect pushes moving objects, such as hurricanes, to the right in the northern hemisphere, but to the left in the southern hemisphere).
Classical physics is therefore perfectly capable of accounting for the observable consequences of the multi-decade cyclic shift presently underway in the Earth's inner core, without any modifications.
There is much more to this that can be written, of course, from a philosophical point of view. Our fallibility as humans forces us to work with absolutes and constants. For instance, the second and the meter are defined with respect to, respectively, transitional frequencies of the caesium-133 atom, and the speed of light in a vacuum, both of which are constant. Could we also define the non-inertial frame of reference that we inhabit on Earth with respect to fixed absolutes?
Such a definition was proposed by Mach in the late 19th century. It is known as Mach's Principle and basically states that local properties of a rotating frame of reference are determined by the distribution of all other matter in the Universe, and specifically the distribution of galaxies and stars in the observable Universe that appear to us to be "fixed". Whilst intellectually appealing, however, Mach's Principle has defied experimental observation to date, and the general consensus is that it is not a necessary prerequisite for the formulation of physical theories.