How Much Room Above the Observed Value? A Reconstruction of the Galaxy-Formation Bound on the Vacuum Density

If the vacuum energy density were much larger than observed, it would dominate the expansion before density perturbations could collapse into galaxies. This paper reconstructs that classic bound with stated, order-of-magnitude assumptions: peaks of contrast delta_eq at matter-radiation equality (z = 3400) growing in proportion to the scale factor, and vacuum domination before collapse excluded. For peak contrasts from 0.001 to 0.03 the cap ranges from 18 to 488431 times the observed density of 2.52 x 10^-47 GeV^4, with the reference peak of 0.003 giving 488. The bound is the only widely discussed argument that lands within orders of magnitude of the observed value, and the reconstruction shows exactly which assumptions carry that result. It is a computation from stated assumptions, not a measurement.