Baby universes merging into ours could mimic dark energy

Absorbing baby universes into our own drives exponential cosmic expansion in this late-time model, replacing the cosmological constant with a dynamical mechanism. The key observable consequence is that the dark-energy equation-of-state parameter w varies with redshift z, crossing below −1 at sufficiently high z — a so-called phantom crossing that standard ΛCDM does not produce. This prediction sits squarely in the target zone of current and upcoming surveys like DESI and Euclid, which are actively measuring w(z).