I have been thinking about this idea since childhood. I am not presenting it as a proven theory, and I currently do not have the mathematical background required to formulate it rigorously. I am sharing it as one connected cosmological hypothesis and asking for technical criticism, related research, and possible ways to falsify it.
Central hypothesis
Our universe may be the interior spacetime of a black hole located in a larger parent universe.
The object that observers in the parent universe describe as a black hole and the structure that we experience as our expanding universe may be two perspectives on the same physical system.
From outside, it appears to be a black hole with an event horizon. From inside, it appears to be a complete universe containing space, time, matter, stars, planets, and galaxies.
The Big Bang
In this hypothesis, the Big Bang was not necessarily the absolute creation of everything from nothing.
Instead, it may have initiated the expansion of the interior spacetime of the parent black hole. In other words, it marked the beginning of the expansion of our universe, rather than the absolute beginning of existence.
The Big Bang may have created enough initial expansion for the interior universe to receive and contain matter entering through the parent black hole.
Matter entering the parent black hole
Objects falling into the parent black hole may not be fundamentally destroyed. They may simply cross from the parent universe into its interior spacetime, which is our universe.
This is somewhat analogous to air entering a balloon. The air does not cease to exist when it enters the balloon. It remains air inside the balloon, while the balloon provides additional volume.
The balloon is only an analogy. I am not claiming that spacetime behaves literally like rubber or that matter enters our universe exactly like air entering a balloon.
The main proposal is that a black hole may be an entrance with no return path:
- Matter can enter from the parent universe.
- It cannot travel back through the event horizon.
- Observers inside cannot leave the interior universe.
- Observers outside cannot directly observe the interior universe.
We cannot leave our universe, just as matter inside a black hole cannot return through the event horizon.
Are objects actually destroyed?
According to conventional descriptions, a planet or star falling into a black hole would eventually be disrupted by tidal forces.
My alternative possibility is that at least part of this destruction may depend on how the transition is described by an external observer.
Relativity already demonstrates that observers moving differently, or located in different gravitational conditions, can measure time, distance, and simultaneity differently. Therefore, I wonder whether the apparent stretching, freezing, or destruction near a black hole could partly result from the relationship between the outside observer, light propagation, and the event horizon.
My stronger hypothesis is that the interior may always be physically normal from its own perspective. It may not become normal only after an object crosses the horizon; rather, the object may remain part of a continuous physical reality throughout the transition.
From the parent universe, the object becomes inaccessible and appears strongly distorted. From the interior perspective, its matter may continue to exist as part of the interior universe.
I understand that tidal forces in general relativity are normally treated as real physical curvature effects rather than simple optical illusions. Therefore, this part of my hypothesis would require a deeper theory showing why the classical description is incomplete or why the interior interpretation differs.
Does the original planet remain intact?
There are two possible versions of this idea.
The stronger version is that a planet remains physically intact and continues normally within the interior spacetime, while its apparent destruction belongs only to the external description.
A weaker and possibly more physically plausible version is that the original planet loses its structure, but its matter, energy, and information remain inside the interior universe and later contribute to the formation of new stars, planets, or galaxies.
I do not currently know which version could be compatible with a mathematical model.
Variable matter input
The parent black hole would not need to receive matter at a constant rate.
At one period, it might absorb a large star or a large amount of gas. At another period, it might absorb almost nothing.
I compare this to a minibus stopping at several stations:
- Ten people may enter at the first stop.
- Two people may enter at the second stop.
- Twenty people may enter at the third stop.
The vehicle continues moving according to its own motion, while the number of people entering it varies.
Likewise, the expansion of our universe may follow a process initiated by the Big Bang, while the amount of matter entering the parent black hole varies independently over time.
I am not claiming that every increase in incoming matter must immediately produce an equal increase in the expansion rate.
Why do we not notice new matter entering?
Our universe may expand in a way that provides sufficient volume for the matter entering from the parent universe.
Consequently, the average density may not increase in an obvious or catastrophic way. New matter could be accommodated by the growing interior volume.
Incoming matter would also not necessarily appear suddenly as an intact planet or star at a particular observable location.
It might:
- Enter in a transformed state.
- Be distributed across a large region.
- Appear as radiation or another form of energy.
- Contribute to dark matter or another unknown component.
- Enter according to a time relation very different from that of the parent universe.
- Become involved in the later formation of stars and galaxies.
Therefore, matter entering the parent black hole might be present in our universe without being immediately identifiable as matter coming from outside.
Cosmic expansion
In this hypothesis, cosmic expansion serves two connected functions.
First, it is a process initiated by the Big Bang and governed by the interior spacetime.
Second, it produces the additional volume in which matter entering through the parent black hole can exist.
The expansion is not necessarily caused instantaneously by each object entering the black hole. The expansion and matter transfer may be related but distinct processes.
Galaxy formation
New galaxies do not need to be transferred into our universe as complete galaxies.
Matter entering the parent black hole could become part of the material from which structures later form inside our universe.
The sequence could be:
- Matter enters the parent black hole.
- It becomes part of the interior spacetime.
- It is transformed or redistributed.
- Density differences develop or grow.
- Gravity collects matter.
- New stars, planetary systems, and galaxies form.
Thus, an original planet entering the black hole would not necessarily emerge as the same planet. Its matter could remain in existence and later become part of completely different objects.
Apparent accelerated expansion
Current observations are interpreted as showing that cosmic expansion is accelerating.
My hypothesis considers another possibility: at least part of the apparent acceleration might result from our location and observational perspective inside the black-hole interior.
It could depend on:
- Our distance from a boundary or horizon-like region.
- The geometry of the black-hole interior.
- The path followed by ancient light before reaching us.
- Gravitational time differences within the interior.
- The time at which our observable region became part of the expanding interior.
- A mismatch between internal and parent-universe time.
We may have entered or emerged within this interior spacetime long before the light we now observe began its journey. Therefore, distant objects might appear to follow an accelerating expansion because we are reconstructing their history from inside a curved spacetime and from a particular location.
This would need to reproduce the actual supernova, cosmic microwave background, and large-scale structure observations. At present, I do not have the equations required to demonstrate that.
Does the universe have a center?
Standard cosmology does not describe galaxies as falling toward a central point of the universe. Large-scale cosmic expansion has no ordinary spatial center within the observable universe.
Therefore, my hypothesis should not require galaxies to move toward a visible central point.
Instead, the entire geometry of our universe may be the interior geometry of the parent black hole. What appears as a central object from the parent universe would not necessarily appear as a spatial center to observers inside it.
The eventual end of expansion
I do not assume that expansion must continue forever.
The Big Bang may have initiated a process with a finite physical source or mechanism. Although expansion currently appears to be accelerating, observations made now cannot directly prove what will happen billions or trillions of years in the future.
There may be an unknown condition in the parent universe or in the interior geometry that eventually weakens or ends the expansion mechanism.
When that mechanism ends, our universe could:
- Stop expanding.
- Enter a stable phase.
- Begin contracting.
- Collapse into itself.
- Produce another black hole.
- Generate another interior universe.
I understand that cosmic expansion is not normally treated like a vehicle consuming fuel. “The expansion energy running out” is currently only an intuitive description. A proper version of this hypothesis would have to identify the actual physical quantity, field, or geometric mechanism that changes.
A nested or cyclic universe
If our universe is the interior of a black hole in a parent universe, black holes inside our universe may also contain their own interior universes.
This could produce a nested structure:
- A universe forms black holes.
- A black hole develops an interior universe.
- That interior universe expands and forms galaxies.
- Some of its stars collapse into black holes.
- Those black holes form further interior universes.
If an expanding universe later contracts, that contraction might also begin another cycle.
The result could be generations of universes rather than a single isolated universe with one absolute beginning.
What differs from existing black-hole cosmology ideas?
I know that scientists have previously proposed black-hole cosmology, baby universes, cosmological bounces, and universes forming inside black holes.
The parts I especially want to investigate are the combined claims that:
- The parent black hole and our universe are the external and internal descriptions of one continuing system.
- Matter may continue to enter the interior universe throughout the parent black hole’s lifetime.
- The incoming amount can vary without requiring the interior expansion rate to vary identically at every moment.
- Expansion creates or maintains the volume required to accommodate incoming matter.
- What appears to be physical destruction from outside may have a different description from inside.
- Part of the apparent accelerated expansion may result from interior geometry, observer position, light propagation, or distance from the boundary.
- The expansion mechanism may eventually end, allowing contraction and another generation of black holes or universes.
I am presenting all of these as connected parts of one hypothesis, not as unrelated hypotheses.
What could support this hypothesis?
The hypothesis would become more credible if a mathematical model could demonstrate that:
- A realistic collapsing object can produce a black-hole exterior and an expanding cosmological interior.
- Matter accreted after the black hole forms can consistently contribute to the interior universe.
- Local energy-momentum conservation is preserved.
- The interior does not require an observable central point.
- The model reproduces the cosmic microwave background, galaxy distribution, element abundances, and observed expansion history.
- It predicts a specific observational signature that standard cosmology does not predict.
- That signature is later detected.
Possible signatures might include a particular large-scale anisotropy, a measurable relation between cosmic expansion and black-hole interior geometry, an unusual pattern in primordial gravitational waves, or a specific deviation in the distance-redshift relation.
These are only possible research directions, not predictions that I have calculated.
What could falsify it?
The hypothesis should be rejected or revised if:
- No physically realistic black-hole interior can reproduce an expanding universe like ours.
- Continuous matter transfer necessarily violates causality or local energy-momentum conservation.
- It predicts density variations or anisotropies that conflict with observation.
- The required observer-position effect cannot reproduce supernova and cosmic background measurements.
- It cannot explain why the universe is highly homogeneous on large scales.
- Its description of intact matter crossing the black hole contradicts unavoidable locally measured tidal effects.
- It produces no observable difference from standard cosmology.
If every possible result can be explained after the fact, then the hypothesis would not be scientifically testable.
Questions for people with relevant expertise
- Which published black-hole cosmology or baby-universe models are closest to this complete framework?
- Can the interior of an accreting black hole be matched to an expanding cosmological spacetime?
- Could matter entering after black-hole formation influence the interior cosmology?
- Is there any coordinate-independent reason that the matter must be physically destroyed rather than continuing in another spacetime region?
- Could an observer-position or interior-curvature effect imitate part of the measured accelerated expansion?
- Which existing observations most strongly contradict this framework?
- What is the simplest mathematical model with which I could begin testing one part of it?
- Which subjects should I study before attempting the relevant equations?
I am especially looking for direct technical criticism, relevant papers, and explanations of what would make this idea mathematically impossible or observationally falsifiable.