What If (Tiny) Black Holes Are Everywhere?

The most striking idea in this discussion is that black holes may not be truly eternal: quantum effects could halt their evaporation at a minimum “Planck relic” size, potentially leaving behind tiny, invisible remnants that could be widespread—possibly even accounting for dark matter. In classical general relativity, an event horizon traps everything, so black holes are perfectly black and can only grow. Hawking’s 1974 work brought quantum mechanics into the picture and showed that event horizons disrupt quantum fields, forcing black holes to radiate thermally and slowly lose mass. But the usual Hawking calculation relies on assumptions that break down when the black hole shrinks to quantum-gravity scales, leaving open the question of what happens at the very end of evaporation.

A key argument for remnants comes from how “thermal” radiation behaves when the available quantum modes become limited. For a large black hole, the surrounding quantum fields have many allowed fluctuations, so the radiation looks smooth and continuous—like a red-hot poker glowing across many wavelengths. As the black hole gets smaller, the allowed vibrational modes narrow. Instead of a steady spectrum, the remaining mass could be emitted in discrete steps. At some point, there may be no allowed transition that can remove the last bit of mass, so Hawking radiation would stop and the black hole would become stable. Estimates place this cutoff near the Planck mass, about 20 micrograms, with an event-horizon size around 10^-35 meters (the Planck length), where general relativity and quantum mechanics are expected to clash.

Whether such Planck relics exist in nature depends on formation pathways. Black holes produced by ordinary stellar deaths are far too large: the smallest of them would take roughly 10^66 years to evaporate completely, longer than the universe’s current age. To have remnants today, black holes would need to be much smaller from the start—masses at or below about a billion tons—so they could decay down to relics within cosmic time. The proposed source is primordial black holes, which could form in the extreme densities of the early universe, potentially in large numbers during inflation when density fluctuations might collapse into tiny black holes.

Planck relics are also pitched as a way to address two major theoretical problems tied to Hawking radiation. If black holes evaporate completely with a perfectly thermal spectrum, the radiation would carry maximum entropy and seemingly erase information about what fell in, violating conservation of quantum information. Remnants offer a “data compression” alternative: information might remain trapped in a stable Planck-scale object rather than disappearing. The discussion also notes tension with the Bekenstein bound on information content, with one speculative workaround suggesting that space inside black holes could expand beyond the event horizon—possibly triggered by a new inflationary phase near the singularity.

Finally, the piece turns from physics to scientific culture, clarifying a stance on the “it’s aliens” hypothesis. The caution isn’t about lacking courage to consider fringe ideas; it’s about confirmation bias—how a favored narrative can cause evidence to be interpreted to fit it. The same episode also corrects a prior mistake about squeezed light in gravitational-wave detection: squeezed light was already used in the most recent observing run, and a LIGO scientist, Maggie Tse, reported up to 50% higher detection rates, matching predictions.