Cosmic Inflation: Unleashing the Universe’s Exponential Expansion

The beginning of our Universe is shrouded in mystery, a mystery that the scientific community is gradually unraveling using the inflationary model of the Big Bang. This concept is striking in its explanation: despite the all-encompassing pull of gravity, it is the effect of negative pressure in the quantum vacuum that could have served as the source of a powerful repulsion, capable of performing the miracle of cosmic expansion.

The central driving force of the model is the hyper-fast expansion, lasting only a fraction of a second—about 10⁻³⁵ seconds—which increases the size of space by an incredible factor of 10^100. This exponential takeoff imbued the Universe with unusual energy, setting the stage for the subsequent formation of cosmic structures such as galaxies. After this phase, the false vacuum loses its properties and the released energy transforms into radiation, continuing to drive the dynamics of the ensuing uniform expansion.

In conclusion, the inflationary model not only unveils the mystery of how the Universe could have originated but also explains the observed homogeneity of cosmic structures. This explanation, bolstered by astrophysical data, stands as a cornerstone of contemporary ideas about cosmogony, inspiring our imagination and renewing our belief in the marvels of scientific discovery.


Which of the modern concepts of the Big Bang theory appears to be the most convincing and why?

The most convincing modern concept is the inflationary model of the Big Bang. This concept attracts attention because it effectively addresses the crucial problem—the necessity for an enormous repulsive force for an event as astonishing as the birth of the Universe, even though gravity acts solely as an attractive force. According to this model, the initial state of the quantum vacuum possessed the paradoxical property of negative pressure, leading to a brief yet exponential expansion of the Universe. This explains how a modest initial phase of hyperexpansion could set the impulse for the further development and formation of cosmic structures, such as galaxies.

Evidence supporting this concept includes, in particular, the fact that the inflationary stage, lasting around 10⁻³⁵ seconds, allowed the Universe's size to increase by roughly 10^100 times in an incredibly short span. After the decay of the false vacuum, the vacuum energy was immediately released as radiation, which provided the push for the following period of standard expansion. Additionally, the exponential expansion characteristic of the inflationary model helps clarify the homogeneity of the observed cosmic structures—an aspect that is corroborated by astrophysical observations.

Supporting citation(s):
"To achieve an astonishing event—the birth of the Universe—a gigantic repulsive force was required. Yet the only one of the four fundamental interactions that manifests on the cosmological scale, gravity, is instead characterized by attractive forces between masses. This problem is resolved in inflationary theory. According to it, the initial state of the quantum vacuum possessed the paradoxical property of negative pressure, which resulted in an enormous repulsive force." (source: link )

"The inflationary stage lasted very briefly—only about 10⁻³⁵ seconds, beginning from the moment the 'world clocks started.' However, during that time the expanding Universe had already increased its size by 10^100 times. After the decay of the false vacuum, the repulsion ceased, and the vacuum energy was instantaneously released in the form of radiation. From that moment, ordinary expansion with positive pressure commenced, propelled by the initial impulse acquired during the inflationary period." (source: link )

"The inflationary model considers exponential expansion as the critical moment for the fate of the Universe, which allows for an explanation of the homogeneity of the observed cosmic structures. Today, few astronomers doubt that, at some point between 10⁻³⁵ and 10⁻³³ seconds after the Big Bang, inflationary expansion occurred." (source: link )