Maybe this solves both dark matter and energy at the same time. Quick backstory: So on top of accounting for unseen mass sprinkled throughout the universe, couldn't the evaporation of an ensemble of microscopic black holes (due to Hawking radiation) also explain universal expansion? As they're all evaporating, is space-time not collectively being put back into the universe back across the event horizon as space-time is distorted less, resulting in exponential universal expansion? No need for dark energy. Edit: I think one thing I said could be wrong. Space-time may never come back across the event horizons, even though the event horizons are shrinking. Still, as the distorted space-time around the black holes relaxes, the collective effect could be universal expansion. The black holes must be sufficiently small enough for some to dissipate significantly on timescales like "only" 14 billion years-ish, if we're seeing expansion effects from that. This also assumes the big bang theory is still at least mostly correct. Wonder what the characteristic black body emission temperature is for the escaping (presumably very redshifted) radiation. I only say that because the escaping photons are theorized to have a maxwellian/thermal distribution. Edit2: Srry, this is still debated. Is the signal nestled somewhere under the CMB? Maybe a fraction of 1 Kelvin? Hmm. I can't think of a better set up than Gran Sasso's liquid Xenon detection scheme, deep underneath a massive mountain range. It should eventually catch a lil' black hole tearing through, right? And as far as I know, they haven't found much of a thing to write home about. Maybe we're doin' it wrong? Devac, help solve cosmology on an internet message board