According to the current Big Bang Model, it suggests that the Universe was dense and small at the beginning and since then it has been expanding rapidly due to inflationary pressure.
We will go through those different phases of the formation of the Universe from the occurrence of Big Bang to the Universe as we see today in the following articles-
General relativity is the present modern theory of gravity and gives the most accurate view of gravity as a manifestation of space-time and matter in curved Non-Euclidean space. Inferring the expansion of the Universe (detected from the behavior of galaxies in the local neighborhood) through general relativity backwards in time suggests that the Universe came from a single point of infinite density and temperature. This suggested that a gravitational singularity existed at that point such that general relativity cannot be applied there leading to a poor understanding of the model of the events of the Universe during that phase.
Present models based on general relativity cannot infer towards the singularity- beyond the edge of the Planck epoch. Under those infinite temperatures and conditions, quantum effects also take considerable charge; such interactions also have to be included in the equations. This calls for the derivation of the Unified theory of gravity or Grand Unification Theory. As said by Stephen Hawking that such a model will explain everything in the Universe and will explain what was at the time of singularity and also what may be beyond Big Bang.
The Big Bang marked that epoch in the time arena when the modern laws of physics i.e. general relativity and standard particle physics came into being. Based on the measurements of Type Ia supernovae and measuring the temperature fluctuations in cosmic background radiation, the so-called time that has passed is equivalent to 13.799 ± 0.021 billion years We call this time period the “Age of the Universe”. Independent measurements of this age support the Lambda-CDM model that describes in detail the characteristics of the Universe.
Written By- Sukhjit Singh
He is pursuing B.Sc in Mathematics Honours from SGTB Khalsa College, Delhi University. He often takes up multiple exciting projects and aims to develop multiple skills.