The formation of our Universe at the time of the Big Bang is still very mysterious, but one theory proposes a hypothesis about our origin: a four-dimensional star collapsing into a black hole.
It is a possibility now discussed: the primordial flash that gave birth to the Universe could have been caused by the formation of a black hole. But not just any: a black hole born from the collapse of a star not having three dimensions, like our cosmos, but four: length, width, height … plus one dimension of which we only know that it would be orthogonal to the first three. Our world would therefore result from the explosion of this 4D star located in a meta-universe.
It was in 2014 that a group of physicists led by Robert Mann, at the University of Waterloo (Canada), formalized this theory for the first time. They have shown that the equations describing the expansion and cooling of the burning material at the level of the horizon of a four-dimensional black hole are in every way similar to those which describe the emergence of our Universe from this burning state and dense that we call big bang.
A three-dimensional membrane
Hence this astonishing supposition: what if the two phenomena were one? In other words, what if the big bang was nothing but a black hole being formed?
This scenario has its roots in the “holographic” principle, which dates back to the 1970s. At the time, the famous theorists Jacob Bekenstein and Stephen Hawking, in Cambridge, show that information swallowed up by a black hole – a three-dimensional object – is proportional to the area of its horizon – a surface that has only two.
In their wake, in 2000, several theorists argued that our Universe could be a kind of three-dimensional membrane evolving in a meta-universe that has four. This is Robert Mann’s starting point: for him, this four-dimensional space could be populated by stars themselves in four dimensions, presenting a life cycle similar to that which we observe in our cosmos.
Then, studying how a black hole is formed in this extended geometry, he comes to show how a universe similar to ours appears in the form of a 3D membrane at the horizon of this black hole.
A new cosmic genesis
This theory has several advantages. First, it resolves the thorny question of knowing what happened at the time of the big bang by purely and simply removing its “mystery”. Better still, it explains why the geometry of our Universe is perfectly flat and not curved: it is enough for this that the 4D star which gave birth to it is quite massive.
As a bonus, here is the puzzle of the homogeneity observed in the cosmos solved. Or the fact that the temperature of the Universe is the same everywhere, while remote regions have no reason to have been in contact from the beginning.
Standard theory evokes a strange phase of accelerated expansion of the Universe, a few fractions of a second after the big bang. With the new genesis, the problem disappears. Quite simply because the beginning is pushed back towards the past, at the time of the collapse of the 4D star, which leaves largely to the burning plasma from which we come from the time to balance!
For now, this new model remains to be confirmed. But if it is confirmed, then we will have the scenario: in the beginning was a 4D star in a meta-universe; it collapsed into a black hole; and our Universe was.