Anthropic Landscape 2D: Cosmological Constant Selection

Multiverse theory only becomes a physical argument, not just a metaphor, when it makes a testable statistical prediction — and the clearest example is Steven Weinberg's anthropic bound on the cosmological constant. This simulator draws thousands of candidate vacua from a flat statistical prior on Λ, the kind of measure a string-theory landscape with an astronomical number of vacua would produce, and applies the real physical selection criterion: a vacuum is habitable only if matter gravity dominates long enough for structure to collapse into galaxies before Λ takes over the expansion. An interactive 2D scatter panel (drag to pan, scroll to zoom) and a live binned histogram show the same sampled landscape from two angles. Adjust how many vacua are sampled, how wide the landscape's prior range is, and how early galaxies must form, then resample to watch how a razor-thin anthropically-allowed sliver survives inside an overwhelmingly Λ-dominated landscape — the same reasoning Weinberg used, years before the accelerating universe was actually observed, to predict Λ would be small but not exactly zero.