Alright I tried following this topic and quite frankly I haven't seen one decent answer. Instead I've read numerous arguments lol. However being that I am new here I will address the original question.
The universe inside a whitehole/blackhole is invalid, it was a model proposal by Poplowskii. The model uses spin and torsion to try to account for a homogeneous and isotropic universe, however it fails to account for early large scale structure formation. However that doesn't stop him from working on it lol...
http://www.nikodempoplawski.com/publications.html
http://arxiv.org/abs/1007.0587
Not too many professional cosmologists think too highly of his work. Although his metrics are kind of interesting. I read tons of cosmology articles and I can say with confidence that his work is rarely cited.
-particularly since his models is also a counter to inflation models. Inflation has too strong of supportive evidence, particulary since they may have found evidence of gravity waves in the CMB. The planck papers also support inflation models with a higher observation agreement towards the single scalar models with low kinetic term. The best fit to observations is the LambdaCDM model. Which is essentially the hot big bang model with cold(non relativistic) dark matter. The hot big bang beginning does not describe the beginning of the universe, it only describes a hot dense state from 10-42 sec forward. The early timeline is based on our understanding of symmetry breaking temperature correlations of particle physics. Essentially when a particle species drops out of thermal equilibrium. Prior to that time our knowledge of physics breaks down.
Anyways another key note on blackholes, they do not feed at consistent rates, so if we were inside one. Shouldn't we also measure varying energy-density distributions in the CMB or within the IGM (Intergalactic medium)? We don't overall the universe is homogeneous and isotropic (Homogeneous no preferred location)(isotropic no preferred direction). This is also why the big bang is not the result of some explosion from some infinitely dense god particle. Multimedia loves to show that analogy lol. The misiscule point described is the start of our lightcone (region of shared causality) In simpler words our observable universe. We do not know if the universe is finite or infinte. We have no means of measuring beyond the cosmic event horizon, so we make no statements about that region, other than we have no reason to think it will be any different than our observable. Now here is some related articles
http://arxiv.org/abs/1304.4446 :"What we have leaned from Observational Cosmology." -A handy write up on observational cosmology in accordance with the LambdaCDM model. http://arxiv.org/abs/astro-ph/0310808 :"Expanding Confusion: common misconceptions of cosmological horizons and the superluminal expansion of the Universe" Lineweaver and Davies http://www.mso.anu.edu.au/~charley/papers/LineweaverDavisSciAm.pdf: "Misconceptions about the Big bang" also Lineweaver and Davies http://arxiv.org/abs/1002.3966 "why the prejudice against a constant" http://arxiv.org/abs/gr-qc/0508052 "In an expanding universe, what doesn't expand? Richard H. Price, Joseph D. Romano http://arxiv.org/abs/1301.0219What's in a Name: History and Meanings of the Term "Big Bang" Helge Kragh http://arxiv.org/pdf/0906.1442v1.pdf Is it possible to see the infinite future of the Universe when falling into a black hole?
my website also has links to professional articles (Non pop media, peer reviewed articles) designed to teach cosmology to the new student, feel free to browse the site, it also includes some textbook style (free Official open source articles)
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