The Big Bang may be a black hole inside another universe

Tim Andersen, Ph.D.
Jul 27 · 9 min read

The idea that we are living inside a black hole isn’t as crazy as it sounds. Black holes warp space and time to the point where space and time reverse roles. For anyone falling into a black hole, the radial dimension, towards the singularity, becomes time and the time dimension becomes like space.

The two well known predictions from this are that, from inside a black hole event horizon, (a) you cannot escape because the way out is back in time and (b) black hole singularity covers a “spacelike” region of spacetime that exists like a barrier so that anything that falls in strikes the barrier simply at different spatial points along the singularity’s extent.

Another prediction is that the infinitely compressed central singularity of the black hole lies in your future as you fall in. When you reach it, nobody knows what happens because the laws of physics as we know them literally break down. Whatever the theory of quantum gravity ends up being might explain it, but for now we have no idea.

The basic idea for the Black Hole Big Bang Theory (BHBBT) is that matter from a mother universe collapses into a black hole. The singularity of this black hole is at a single point in space with respect to anyone in the mother universe. But, because of the reversal of time and space for anyone inside the daughter universe, that point in space r=0 become their initial point in time, t=0. Hence, what was a singularity in space is now a singularity in time, just like the Big Bang.

This means that any matter falling in from the mother universe will disappear from that universe and emerge at the initial t=0 point of the daughter universe thoroughly scrambled.

Not only that, but what emerges at the Big Bang is not just the matter that was there at the black hole’s formation but all matter that ever fell into it. That is because time at the black hole’s singularity is essentially perpendicular to time in the mother universe outside.

The reason why a whole other universe can be contained inside another one has to do with the strange way in which time and space can be warped, stretched, compressed, and twisted. What appeared to be a deadend at the center of a black hole, can instead be a passage way into the birth of a new universe.

You can have many interconnected universes this way, in which mothers give birth to daughters which give birth to more daughters, and so on ad infinitum. Thus, far from being only 13.8 Bya (Billion years ago), the whole interconnected cosmos can be infinitely old or more properly timelike paths can be infinitely long into the past passing from universe to universe.

This is not the same as the Many Worlds Interpretation of quantum mechanics that I have criticized in recent articles of course. There is no constant splitting of universes based on quantum observations. Rather, this is a process that occurs through black hole formation, and each universe would be essentially unique, although daughter universes would share characteristics of their mothers. There wouldn’t be exact copies of you running around.

Indeed, some have argued that a process of natural selection may take place with these universes, since the only universes that can reproduce are those that can form black holes. It is also a potential resolution of the anthropic principle, the theory about why human beings exist, since each universe may have slightly different laws of physics. Just as not all planets can support life, not all universes can. No many worlds interpretation required just many distinct universes within a single spacetime.


The Standard Big Bang Model

Where is the center of the universe?

Black holes, on the other hand, have their centers at a point in space, r=0 in coordinates centered on the black hole singularity. Thus, they are fundamentally different from the Big Bang singularity.

So how can we be inside a black hole?

The metric is what tells us how space and time behave and what distances mean at any given point. Intense concentrations of matter can warp space and time so that the metric changes what space and time mean for different observers.

For an observer outside a black hole, called the far observer, the singularity is at a point in space. For the observer inside the event horizon, however, the sign of the r and t elements of the spacetime metric change places. Now, for the near observer, the singularity is at a point in time, some time in the future.

The BHBBT suggests that, at least for certain types of singularities, once matter reaches it, it enters a new universe where time at the singularity is the initial point of that universe.

To visualize this, imagine you are an ant crawling on a table. As you crawl along, you crawl down a slope. The slope gets steeper and steeper until it is completely vertical from the direction you were crawling in. Suddenly, it ends in a point. This is typical of how black holes are portrayed. But now, instead of ending in that point, it expands out again from the point, flaring into a cone. Through some miracle of quantum mechanics, you pass through the point and emerge into the cone. Now you are in a new universe perpendicular to the one you left.

Why is the BHBBT a good idea?

The Horizon Problem

Inflationary theory doesn’t solve a number of other problems including the fluctuation problem, super-Planck scale physics problem initial singularity problem, or the cosmological constant. It doesn’t matter exactly what all these mean. The point is that it is far from a panacea.

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The horizon problem shows that two regions of the universe, as given by two areas of the sky of the CMB, would not have had time to communicate information. In fact, they would have only had about 300 Ky to have become correlated since the Big Bang itself. Therefore, they should not be correlated with one another but only with nearby regions. But we observe that the entire universe is largely correlated. (Image by Wikipedia User Theresa knott)

The horizon problem is address by the BHBBT model simply by pointing out that matter falling into the black hole has plenty of time to interact with other matter falling in before reaching the singularity. While this is not on the daughter universe’s clock yet, it is in that quasi-time that exists within the black hole event horizon that is neither part of the mother universe nor the daughter but is somewhere in between.

The Flatness Problem

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Source: https://wmap.gsfc.nasa.gov/universe/uni_shape.html Author: NASA / WMAP Science Team

Why the universe has exactly the correct matter density to be flat, called the critical density, is one problem. What that matter is is another: we don’t know. The universe has three general types of matter: baryons, which are what we think of as matter, dark matter, and a third form. We call it dark energy and we have no idea what it is. Dark matter, at least, we can observe in the rotations of galaxies and other gravitational behavior. Dark energy we only see in the expansion of the universe and to explain it we introduce a constant into Einstein’s equations called the cosmological constant which makes the universe’s density even out to the critical density.

We believe that if the critical density were not 1 then we would not be here. If it were more than one, the universe would have collapsed long ago, perhaps only an instant after the Big Bang, if it were less than one, the universe would have expanded so rapidly that galaxies would not have formed.

The BHBBT resolves the flatness problem by connecting the black hole interior to what is called a de Sitter space, which represents our universe, with an infinite amount of time. Thus, the observer inside the black hole approaches the singularity and emerges into de Sitter space and continues on for infinite time into that space.

It turns out that the only solution that allows a de Sitter space to connect to a black hole is a flat one. Thus, dark energy isn’t a form of matter energy but is actually the result of a spatial topology (shape) inherited from the black hole.

Black Hole Information Paradox

Is it true?

[Updated: The previous version of this article said the future of the universe could be seen from inside the black hole event horizon. This can only happen if the black hole is rotating and/or charged.]


Pathria, R. K. “The universe as a black hole.” Nature 240.5379 (1972): 298–299.

V.P. Frolov, M.A. Markov and V.F. Mukhanov, “Through a black hole into a new universe?”,Phys. Lett.B 216(1989) 272.

Smolin, Lee. “Did the universe evolve?.” Classical and Quantum Gravity 9.1 (1992): 173.

Stuckey, W. M. “The observable universe inside a black hole.” American Journal of Physics 62.9 (1994): 788–795.

Easson, Damien A., and Robert H. Brandenberger. “Universe generation from black hole interiors.” Journal of High Energy Physics 2001.06 (2001): 024.

The Infinite Universe

First Principles in Science, Philosophy, and Religion

Tim Andersen, Ph.D.

Written by

Studied statistical mechanics, general relativity, and quantum field theory. Principal Research Scientist at Georgia Tech.

The Infinite Universe

Dedicated to exploring the philosophy and science of time, space, and matter.

Tim Andersen, Ph.D.

Written by

Studied statistical mechanics, general relativity, and quantum field theory. Principal Research Scientist at Georgia Tech.

The Infinite Universe

Dedicated to exploring the philosophy and science of time, space, and matter.

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