This is my theory, based on Einstein's Special & General Theories of Relativity, and Stephen Hawking's equations for Black Hole radiation, and the Schwarzchild radius of a black hole.

The universe is an enormous black hole. According to observation, many billions of years ago, matter in the universe was dense enough to form an event horizon, to bind together gravitationally within a certain radius. The universe didn't collapse, but nothing could travel outside the Schwarzchild radius. This radius might be upwards of 70 billion lightyears or more (I haven't done the calculation recently). The same equations predict that the average density of matter inside a black hole decreases as the black hole grows. While matter in a solar-mass black hole might mass many tonnes per milliliter, the density of a black hole the size of our solar system might not be much heavier than water or air. A black hole of cosmic proportions would be so vacuous inside as to be indistinguishable from outer space.

Matter falling into a large black hole would not be torn apart. In fact there would be more gravitation from other infalling particles. Stars and galaxies could form inside a very large black hole. And they would orbit around inside forever, but still never escaping the event horizon. They could supernova and form smaller black holes. These black holes would grow, eventually reaching a stage of geometric progression in growth that I call a "Flashover Event". During a Flashover Event the event horizon grows faster and faster, expanding outward nearly instantaneously and enveloping the whole volume of its parent universe/black hole. Our universe contains hundreds of billions of these nested black holes at the centers of galaxies. Each is slowly accumulating matter in a process of unknown duration, someday reaching that critical point when they will Flashover. Each one may Flashover separately, or it might require an agglomeration on a cosmic scale before Flashover occurs. I don't know. We don't see evidence for extremely large black holes, but we don't see evidence for more than one so-called Big Bang event either. It's a matter of opinion.

Where does cosmic inflation fit in?

When an object is moving at high speed it will appear to contract in length relative to a stationary observer. This is called "length contraction". When an object is positioned on the rim of a spinning disk it will also experience a length contraction due to its instantaneous tangential velocity. But it will also experience a centripetal force equivalent to an acceleration. This has been found equivalent to a gravitational force. Tests have also shown that gravity can cause time dilation as well has length contraction. Since we live in a black hole, we are accelerating, and therefore contracting. Distant objects will appear to dilate. This is due to the long-range effect of living in a gravity well. A very big one. The difference in velocity may be less significant than the difference in gravitational acceleration at large cosmic displacements.

New terminology:

1. Flashover Event - previously referred to as the big bang, now understood to be the final growth stage of black holes.

2. Space Dilation - previously referred to as cosmic inflation, now understood to be the opposite of length contraction when observing distant objects at different radial locations inside a gravity well.

3. Primordial Matter - when a small black hole recombines heat with matter, increasing its chemical & nuclear potential energy and reducing its entropy. Nothing can escape from a black hole, not even heat.

4. Mathematical Space - previously referred to as dark energy, the non-physical universe of logic beyond our own, consisting of bits either interacting or not interacting, not bound by event horizons, but which partially emerge into our own, manifest mass, and self-encapsulate within an event horizon. Bits which do not interact in mathematical space do not manifest themselves within our event horizon since no information is exchanged and relative motion cannot be measured.

Thing get a little sketchy at this point.