Did our universe come from nothing? Why yes, why not

 From the mysteries of the cosmos, there has always been a fascination with the origins of the universe, specifically the events preceding the Big Bang. We have scrutinized the earliest moments of time, tracing back to mere billionths of a second post the cosmic explosion. The consensus argues that nothing arises from void; a principle dictated by the laws of physics. Yet, the question remains unanswered, unless we delve into the quantum state of the universe during the Planck era (the period between zero instant and 10^-43 seconds post the Big Bang).

A Universe Conceived from Near Nothingness: Roger Penrose's Theory

Roger Penrose, the 2020 Nobel laureate in physics, proposed a bold and contentious model of a universe conceived from near nothingness. He was inspired by the mathematical correlation between a minuscule, dense, and hot universe and an expansive, cold, and empty cosmic state. He theorized that these polar opposite states could converge into a single entity at their limit. This paradox suggests that an absolute lack of matter could potentially spawn all the observable matter in the universe.

The Enigma of Nothingness: The Big Bang's Precursor

In Penrose's perspective, the Big Bang emerges from near nothingness. This arises when all matter from a preceding universe has been devoured by black holes, which subsequently transform into photons dispersed in the vacuum. The universe, then, may be born from something that resembles nothing. This "nothing" is, however, still a physical universe, albeit devoid of matter. This leads us to question how this state can simultaneously be cold and empty while also being hot and dense. The answer lies in a geometric transformation that alters the body's dimensions while preserving its shape: conformal rescaling.

The Confluence of Two States: The Shape of the Universe

Penrose demonstrated how these two contrasting states—cold and dense, hot and dense—could be linked through the geometry of their spacetime, not their size. The concept of dimension becomes irrelevant in these extreme environments. In conformal cyclic cosmology, the explanation flows from the old and cold to the young and hot. The dense state's existence is a direct consequence of the cold, empty state. Dimensions and time lose their meaning at this stage. These contrasting states exist on separate timelines, with the cold, empty state persisting indefinitely from an observer's perspective in its own time geometry, while the hot, dense state exists on a new timeline.

To provide a more accurate description, it could be said that the hot, dense state is birthed from, or actualized by, the cold, empty state. These are profound concepts frequently explored by philosophers, particularly in the realm of quantum gravity, where conventional cause and effect appear non-existent.