Delayed Phase Transition Baby Universe
Our universe may be a baby universe formed inside a primordial black hole during a delayed first-order phase transition.
Placeholder for a 3D visualisation of Black Hole Genesis. The interactive scene will land in Phase 3. A black hole and a Big Bang both involve singularities; perhaps they are two sides of the same event. The collapse of a sufficiently massive object in a parent universe can produce a new expanding region of spacetime, which from the inside looks like our universe began with a Big Bang.
In one sentence
Coleman-De Luccia-style bubble nucleation in a supercooled first-order phase transition can produce inflating baby universes that appear externally as super-critical primordial black holes.
The claim
Huang and collaborators show that if the early universe undergoes a delayed first-order phase transition, bubbles of true vacuum can nucleate and inflate into self-contained baby universes.
From outside, each such bubble appears as a primordial black hole of super-critical mass. Our universe could be the interior of such a bubble, observed as the cosmos we see while existing as a PBH from the parent universe's perspective.
The family stance
A higher-dimensional parent universe existed before ours. Something collapsed in that parent universe, and the gravitational singularity at the center of the resulting black hole became the seed of our universe. We live inside that black hole.
Predictions
- Super-critical primordial black hole population in parent universes
- Specific gravitational wave signatures from the delayed phase transition that could be detected in cosmological surveys
Evidence
- Huang et al. (2025) provide explicit calculations showing the mechanism is consistent with Coleman-De Luccia formalism and produces observationally testable PBH signatures.
Counterpoints
- Requires a specific delayed first-order phase transition in the early universe, which is model-dependent.
- The PBH signatures predicted are at the edge of current observational sensitivity.
Variants in this family
▸Go deeperTechnical detail with proper terminology
Builds on Coleman-De Luccia bubble nucleation formalism from Quantum Vacuum Mechanism family. See arXiv:2505.23007 for the detailed calculation.
References
Last reviewed May 14, 2026
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