The CMB-calibrated cosmic age is 13.79 Gyr while the oldest globular clusters date to 12.5 to 13.5 Gyr and Methuselah-class stars to 12.0 +/- 0.5 Gyr: a few-hundred-Myr margin. If the local H₀ = 73 is the true global rate, the flat ΛCDM age drops to about 12.6 Gyr, younger than the oldest stars, and the 1990s age crisis returns. The model cannot accept its own local expansion measurement without breaking its clocks.
One global H₀ sets one global age: t₀ scales inversely with the expansion rate, so the model is forced to choose between the local measurement and the stellar chronometers. There is no mechanism by which a region of the universe can expand faster than the whole without the age bookkeeping collapsing, so the model has nowhere to put the 73.
SCT replaces the hot-dense-center with a superluminal collision, and the constant Λ with the dynamical ratio Λ_eff(x,t) = C × Λ_parent(x,t) / λ_local(x,t) (P17). The 73 is then an environmental reading: the KBC supervoid and the temporal evolution of Λ_eff enhance the locally sampled expansion by 4 to 7 km/s/Mpc (P19) without changing the global history. The clock that sets the age of our thermal patch is the global one, anchored at the CMB frame and consistent with H₀ = 67.4, so the age stays 13.8 Gyr and the oldest stars fit with room to spare. The vice releases because the two H₀ values were never measuring the same quantity.
SCT adds a sharper chronological statement of its own. The Big Bang is t = 0 of our local thermal history, not of existence (P1): the matter predates the collision (P25), but every star we can observe condensed from the post-collision thermalized plasma, so no local object can be older than 13.8 Gyr. Stellar ages crowding the cosmic age from below are exactly the expected population edge, the first condensations after recombination.
This is the same local Λ_eff enhancement that explains the megamaser H₀, the Migkas anisotropy, and the ladder-CMB split. There is no need to invoke early dark energy, which buys a higher global H₀ by paying with an age the stars forbid.
A uniquely SCT kill: a single stellar object robustly dated older than the local thermal age of 13.8 Gyr, beyond all modeling uncertainty, would falsify the collision chronology outright, since SCT permits no surviving pre-collision stars inside the thermalized patch. In the other direction, environment-tagged expansion measurements finding no void-versus-overdensity H(z) difference at the 2 percent level remove the mechanism that lets the global age coexist with the local 73.