Afshordi's Holographic Big Bang
A four-dimensional star collapsed in a five-dimensional bulk, throwing off a three-dimensional membrane that became our expanding universe.
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
Afshordi and collaborators proposed in 2014 that our 3D universe is the holographic remnant of a 4D star that collapsed into a 4D black hole in a higher-dimensional parent universe.
The claim
The proposal works like this. The parent universe has four spatial dimensions. In that parent universe, a massive star formed and eventually collapsed, the way stars in our universe collapse into black holes. Because the parent universe is one dimension higher than ours, the event horizon of the resulting 4D black hole is a three-dimensional surface, just like the spatial geometry of our observable universe.
Our universe is that three-dimensional surface. We live on the holographic event horizon of a higher-dimensional black hole. The flatness and uniformity of our universe, which inflation explains by an early period of accelerated expansion, this model explains as a direct consequence of being the surface of a smoothly collapsing star.
The proposal is part of a broader research program in holographic cosmology that draws on Maldacena's AdS/CFT correspondence in string theory. Crucially, it makes specific predictions about deviations from a perfectly scale-invariant cosmic microwave background, which can be tested against Planck satellite data.
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
- Specific small deviations from scale invariance in the CMB power spectrum, distinguishable from inflation
- Cosmic flatness as a direct consequence of black hole geometry, not requiring inflation
- No need for a primordial singularity; the apparent Big Bang is the formation event of the parent black hole
- Universe is genuinely three-dimensional, with the perceived bulk being holographic
Evidence
- Holographic principle is well-established in theoretical physics through AdS/CFT correspondence
- Model makes falsifiable predictions about CMB structure
- Avoids the initial singularity problem without requiring inflation
- Naturally explains the flatness problem
Counterpoints
- Requires a four-dimensional parent universe whose own origin is unexplained
- Initial Planck satellite analyses (2015) showed the predicted CMB deviations did not perfectly match observations, though revised parameters in subsequent papers fit better
- Most cosmologists prefer inflation, which is observationally simpler and doesn't require a higher-dimensional bulk
- Holographic cosmology in general remains a minority research program
Variants in this family
▸Go deeperTechnical detail with proper terminology
The proposal builds on the holographic principle, the idea that physics in a region of space can be fully described by information on the surface of that region. AdS/CFT is the best-known example: physics in a five-dimensional anti-de Sitter space corresponds to a four-dimensional conformal field theory on its boundary.
In the Afshordi-Mann-Pourhasan model, the parent universe is approximately Minkowski space in five dimensions (four spatial + one time). A star in that space collapses to form a black hole whose event horizon is a three-dimensional surface. The induced metric on that surface is approximately Friedmann-Robertson-Walker, the standard cosmological metric.
The model's predicted CMB power spectrum has a specific dependence on the mass and angular momentum of the 4D collapsing star. Comparison with Planck data has constrained these parameters but has not ruled out the model.
Afshordi co-authored the 2025 popular book "Battle of the Big Bang" with Phil Halper, which presents this and 24 other origin models as alternatives to standard inflationary cosmology.
References
- Needs verificationPourhasan, R., Afshordi, N., Mann, R. B. (2014). "Out of the white hole: a holographic origin for the Big Bang." JCAP 04:005
- Needs verificationAfshordi, N., Mann, R. B., Pourhasan, R. (2014). "The black hole at the beginning of time." Scientific American 311(2), 36
- EstablishedAfshordi, N., Halper, P. (2025). "Battle of the Big Bang: The New Tales of Our Cosmic Origins." University of Chicago Press
Last reviewed May 14, 2026
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