Physicist says our Universe could have spawned from a black hole
According to our best understanding of the Universe, if you travel back in time as far as you can, around 13.8 billion years or so, you'll eventually reach a singularity - a super-dense, hot, and energetic point, where the laws that govern space-time breakdown.
Despite our best attempts, we can't peer past that singularity to see what triggered the birth of our Universe - but we do know of only one other instance in the history of our Universe where a singularity exists, and that's inside a black hole. And the two events might have more in common than you've ever considered.
http://www.sciencealert.com/physicist-says-our-universe-could-have-emerged-from-a-black-hole
For long time seemed the Friedmann equation is able to explain universe, but in recent years, the cosmological constant was of interest to cosmologists. However, these two equations are unable to explain before the Big Bang.
According to CPH Theory, our universe has born of an absolut black hole:
https://www.researchgate.net/publication/309153372_What_is_CPH_Theory
https://www.researchgate.net/publication/279446746_Graviton_and_cosmology_equations_before_the_Big_Bang?ev=prf_pub
Article What is CPH Theory?
Article Graviton and cosmology equations, before the Big Bang