Ch.01 Before the UniverseBlack Hole Genesis

A higher-dimensional star collapsed into a black hole. Its debris became our 3D universe.

Afshordi's Holographic Big Bang

2014Niayesh Afshordi, Robert B. Mann, Razieh PourhasanFrontierAlso answers, Ch.02 The Origin of Our UniverseAlso answers, Ch.05 The Dark UniverseAlso answers, Ch.06 Black Holes3 primary sources, 3 established Reviewed May 14, 2026

A four-dimensional star collapsed in a five-dimensional bulk, throwing off a three-dimensional membrane that became our expanding universe.

Visualisation · Black Hole Genesis

event horizon: The boundary around a black hole inside which nothing, not even light, can escape.
inflation: A brief burst of accelerating expansion in the very early universe, smoothing out and stretching whatever existed before.
string theory: A framework proposing that fundamental particles are tiny vibrating strings rather than points, requiring extra dimensions of space.
cosmic microwave background: The faint, uniform glow of light released about 380,000 years after the Big Bang, when the universe first became transparent.
singularity: A point in a theory where quantities like density become infinite, signaling the theory has broken down.
bulk: The higher-dimensional space in which lower-dimensional branes are embedded.

§1 · The claim, 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.

§2 · Why it might be true

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.

§2.5 · 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

§3 · What you'd need to test it

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

§4 · Where it breaks

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

Go deeper

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.

▸§5 · Who built it, and when(3 sources, 3 established)

Established
Pourhasan et al. (2014). 'Out of the White Hole: A Holographic Origin for the Big Bang.' JCAP 04, 00518 citations
Established
Afshordi et al. (2014). 'The Black Hole at the Beginning of Time.' Scientific American 311(2), 36
Established
Afshordi & Halper (2025). 'Battle of the Big Bang: The New Tales of Our Cosmic Origins.' University of Chicago Press

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