The Big Bang was a cosmic singularity in which space-time and matter themselves were created and the universe began. This model suggests that, starting with a very small fraction of a billion years in the early universe, it expanded into the vast, cold, diffuse universe we see today. The “Big Bang” model is the result of the work of Lemaitre, Gamow, and colleagues, who, by reversing the observed expansion, conclude that the universe began at the end of the first hundred million years of our solar system’s history.
Fred Hoyle, a non-believer, is credited with coining the term “big bang” mockingly at first, although he preferred the theory of steady state at the time. At its core, the Big Bang theory suggests that the matter of the universe originated about a billion years ago through a singularity, an expansion of space – time and matter. The universe as we knew it at first was known as the “steady state” of the universe, which expanded according to the singularities. The Big Bang theory, widely considered the leading explanation for the origin of the universe, is the model of the steady state universe. The model of “steady state” is the most popular version of this theory and the one most closely related to the theory of steady state.
Cyclic theory agrees that 14 billion years ago there was a violent event, an event called the “Big Bang,” but it is not the beginning of space – of time. It is true that the universe has expanded and cooled down in the last 14 billion years, it is true that galaxies and stars have formed, and it is true that space, time and matter have all formed in what we still call the Big Bang. The event responsible for the structure of our universe in its present form occurred in the first moment after the biggest bang, but this was not a beginning in space and time, nor did it cause the formation of galaxies or stars.
Of course, no one was there to testify, but physicists and astronomers are confident that their “Big Bang Theory,” as they often call it, provides the best explanation of how the cosmos came into being. The Big Bang is a unique catastrophic event that began 14 billion years ago in the early universe and marked the fiery birth of the universe. Physicists sometimes compare space-time with a “quantum foam,” a virtual particle that constantly bursts into existence, and theorize that random fluctuations in this quantum foam triggered the Big Bang. We know what came next, but what happened exactly at the moment things started is still a bit nebulous and we have forgotten a few things since it happened.
The short answer is that we don’t know what triggered the Big Bang, but observations with telescopes show that the universe was very small 13.8 billion years ago. The universe is about 1.5 billion light years away from us, much larger than the Milky Way and about ten times larger than our sun. Observations also suggest that the universe seemed to expand very quickly after the first split second, and then slowed down. The expansion spread everything and made the universe transparent, but not to the point of visible light, like the sun.
The light that is released during this transition, the so-called cosmic microwave background (CMB), still exists. Observatories like WMAP and Planck then used the Cmb to tell us a lot about the overall structure and content of the cosmos. These discoveries have cemented the Big Bang theory as a good description of our universe. The first people to think scientifically about the origin of the universe, were Catholic priests. The universe began with the Big Bang, a huge explosion of light from the beginning of time in the early universe.
Everything now in the universe was compressed into a very small volume, and an enormous explosion, the Big Bang, caused it to expand rapidly. The explosion was caused by the merger of two very large objects, a black hole and a neutron star. The age of the universe is estimated to be about 4.5 billion years, beginning at about the same time as the Big Bang itself, i.e. about 1.6 billion years ago. However, the earliest time in the universe, before the Big Bang, has been the subject of extensive speculation. Through experiments with high-energy particle accelerators and astronomical studies that looked deep into the universe, scientists have constructed a timeline of events that began with the Big Bang and led to the current state of cosmic evolution.
Given that the laws of physics as we know them could not exist at that time, it is difficult to fathom how the universe could be governed. We know that gravity and quantum physics make no sense in extreme cases, and this makes it possible that there is a singularity, a place where the physical law is no longer useful, as before the Big Bang.