I was also just making sure that my ignorance was not any deeper than I suspected it to be.
As you are a geophysical specialist, I would have expected that you might not be entirely satisfied with explanations of physics like Lorentz, Minkowski, and the like propose.
Sure, you could carry with you some sort of holographic laser device that sets up the unbound photonics equivalent of Einstein's clock and meter stick inertial reference frame grid everywhere you go, on a relativistic celestial train or whatever. And carrying around all that geometrical infrastructure with you will not avail you very much. If space curves around a planet, your grid will not follow that curve as much as you might expect, or even for the reason you expect. The Earth orbits the Sun orbits the galaxy falls into Andromeda and follows it in the direction of the great attractor while the entire known universe accelerates outward and / or spins. How will your grid respond to all of these relative motions?
I suppose Einstein liked trains because his theory illustrates a physical reality about trains not so obvious with particles or photons. Unlike the holographic grid, trains have much more moving inertia in one direction (along the straight track) than another (the amount of force needed to derail it).
Michaelson Moreley was all about trying to see the equivalent of traction in the aether that was theorized to be the medium through which the light traveled. If you could actually detect that, then space itself would have inertia and trains could use that instead of track, and starships with frictionless drives and also perpetual motion machines driven by the aether wind could be used to generate electricity from relative motions.
The Higgs boson is an excitation of the Higgs field, has the equivalent rest mass of a tellurium nucleus and decays in about a zeptosecond into either a pair of gluons (strong force) or a pair of electrons (EM force). Particle physicists claim that the inertial rest mass it imparts to electrons, quarks, electroweak bosons, neutrinos, and their antiparticles is in no manner related to gravitational mass, the only other thing in the universe that imparts a kind of inertia that is not entirely at rest.
If you see in this a looming crisis in physics that is the result of too much mathematical woo and not enough physical substance, or even an elementary understanding of what inertia is about, you would not be alone. This happened mainly because leaving out time as a variable mitigated a problem in terms of too many infinities. It also effectively eliminates inertia. Time was simply replaced with probabilities. And it did work brilliantly. Until Higgs was discovered, forcing them to remember what inertia was supposed to do.
Einstein's Princeton buddy Kurt had a lot of substance to say about the limitations of mathematical woo. Kurt left Minkowski's star student Hilbert with a lot of mathematical woo egg on his face, in actual fact. Any symbolic language, including any system of mathematical reasoning, is logically incapable of capturing all of the truth there is, in physics, or anything else. This is because, by its very nature, gaps in understanding naturally arise because no symbolic system that is not physical can capture all of the truth of physical reality. Whatever you choose to ignore may not be ignored by physical reality, and it will be sorted out in detail there independent of whether as a practical matter, you can calculate it or not. For all their fuss about the math, they are more easily blindsided than they are prone to admit. Scores of mathematicians wasted their finite lives trying to calculate the last digit of pi.
Sorry. I know that I promised, no more soliloquies.
