As usual, these astrophysics questions prove to be much more
challenging than they initially seem. I had been working on issues
close to this one, so I had got to believe that half the way was done,
but this field is so fascinatingly complex and spread out that every
question about it is a new beginning.
The search for information on your question first of all shows that
scientists in the field face an admitted uncertainty about how to
conceive the universe. However, it doesn't seem that this uncertainty
disappoints them in the least -- on the contrary, the scientific
community seems to be driven by the excitement of exploring the
possibilities and limitations of the theories currently considered and
their interrelations. Amid these uncertainties and explorations,
serious works modeling the universe as a black hole do exist, more
Now, scientists are very much aware of the incompleteness of the
available theories to provide with fully consistent models, so they
themselves typically point out the flaws of their proposals needed of
During the last hundred years the research on the largest objects --
stars, galaxies and, ultimately, the known universe -- became
inseparable from the research on the smallest compounds of the
existence. The sole idea still currently accepted that the whole known
universe is likely to have emerged from an infinitesimal singularity
is a major example. But also the understanding of how the elements
that make the existence behave have a direct impact on how is the
shape of the whole universe, its geometry, age, foreseeable duration
-- and vice-versa -- because the theoretical models and their
mathematical formulations interrelate them.
The two major theories explaining most -- but not all -- physics
phenomena currently are Einstein's General Relativity and the Quantum
Field Theory (you can learn further about them in the very instructive
-- though technically difficult in part -- article "The Second
Superstring Revolution" by John H. Schwarz from the California
Institute of Technology -CalTech- at
particularly on this point at
subsequent links). The Superstring Theory explores the possibility to
overcome the contradiction between the other two theories.
The Superstring Theory proposes mathematical solutions with more than
the traditional four dimensions (three for space and one for time), in
a number that vary according to the phenomena which are subject of
modeling. As introduced in the respective article at Wikipedia,
"String theory is a model of fundamental physics whose building blocks
are one-dimensional extended objects (strings) rather than the
zero-dimensional points (particles) that are the basis of the Standard
Model of particle physics. For this reason, string theories are able
to avoid problems associated with the presence of pointlike particles
in a physical theory. Studies of string theories have revealed that
they require not just strings but also higher-dimensional objects" or
"membranes" which have been dubbed "branes".
I mention this because some scientists who either propose possible
models of the universe as black holes, or explain black holes as being
consistent with the characteristics currently attributed to our
universe, can do so supporting their mathematical speculations on
n-dimensional space-time conception coming from the superstring
theory, such as "The universe as a five-dimensional black hole", by
Sanjeev S. Seahra1 and Paul S. Wesson2 (see reference and abstract
). Abstract: "We show the geometrical equivalence of two
five-dimensional metrics, one describing a cosmology which smoothly
embeds the standard Friedmann-Robertson-Walker-Lemaître models, and
another describing an object which topologically is a black hole. The
solutions can be interpreted using either membrane or induced-matter
theory. We outline the main physics, wherein the horizon of the black
hole is connected to a big bounce in the cosmology, which may in turn
be connected to a phase change in the vacuum." Unfortunately, the
article is not available for free, but is purchasable at that link,
where also an email address for one of the authors is provided.
Another proposal of a black hole / universe model:
Quantum black hole inflation
Dept. of Physics, Yarmouk University, 21163 Irbid-Jordan
"the universe may have been born as a black hole and is still is. This
idea is not new, and there are a number of investigations that support
it; for example it was already shown long ago by Oppenheimer and
Snyder  that the inside of the Schwartzchild solution could be a
Friedmann universe. Moreover it was shown by Pathria  that our
present universe may be described as an internal Schwartzchid solution
if it has the critical energy density. More recent investigations 
based on the assumption of the existance of a limiting curvature have
shown that the inside of a Schwartzchild black hole can be attached to
a de Sitter universe at some space-like junction which is taken to
represent a short transition layer. Other senarios in which the
universe emerges from the interior of a black hole are also
 J. R. Oppenheimer and H. Snyder, Phys. Rev. 56, 455 (1939).
 R. K. Pathria, Nature 240, 5379 (1972).
 V. P. Frolov, M. A. Markov and V. F. Mukhanov, Phys. Lett. B 216, 272 (1989).
 D. A. Easson and R. H. Brandenberger, ?Universe Generation from
Black Hole Interior?, hep-th/0103019.
In the very illustrative article about black holes by David M.
Harrison, from the University of Toronto, where it explains the
Schwarzschild radius -- a magnitude related to the description and
behavior of black holes -- we can read: "For a mass of 2.5 x 1053 kg,
i.e. a 2 and a 5 followed by 52 zeroes kg, the Schwarzschild radius is
about 17 billion light years. This huge mass is an estimate for the
total mass of the universe. Also, given that the age of the universe
is 15 billion years or so, 17 billion light years is awfully close to
the size of the universe. Does this mean that the universe itself is a
"It turns out that this question is the same as asking: is the
universe closed. If the universe is closed, then it is fairly accurate
to say that it is a black hole."
Philip Gibbs, of the University of California Riverside, explains
another twist in his article "Is the big bang a black hole?"
"It has been suggested by Stephen Hawking that once quantum effects
are accounted for, the distinction between black holes and white holes
is not as clear as it may seem. This is because of Hawking radiation
which shows that black holes can lose matter. (See the relativity FAQ
article on Hawking radiation.) A black hole in thermal equilibrium
with surrounding radiation might have to be time symmetric in which
case it would be the same as a white hole. This idea is controversial,
but if true it would mean that the universe could be both a white hole
and a black hole at the same time."
(A white hole is a hypothetical celestial body conceived as "the time
reversal of a black hole", see Wikipedia at
As usual, these astrophysics questions do not lead to conclusive
answers. Maybe in other times -- namely, the happy two centuries of
the confident Newtonian era -- there was a golden age of more
certainty. But I think you know that already. Now the point is that
according to this research, yes, it is possible that our universe is a
black hole, but for now this is just theoretical speculation, as valid
as other different theoretical speculations.
I hope this answer satisfy your requirement. You already know that you
can count on me for clarification if you find it necessary. Thanks for
your *very* interesting question.