The Big Bang is massive explosion that according to a scientific theory, gave rise to the universe. This theory indicates that the universe is 13.8 billion years old, expanding thanks to the explosion in question.
What is the Big Bang theory simple?
After the expansion, the universe began to cool down. So the first subatomic particles would have formed and then the atoms. Gravity brought these elements together for the development of stars and galaxies.
The Big Bang relates to the notion of cosmic expansion. In 1927, Georges Lemaître noted that if the universe expanded continuously, there must have been a single point of origin in the past.
That origin would be the Big Beng. The growing separation of galaxies that Edwin Hubble discovered in 1929 also served to support this hypothesis.
Scientists like Roger Penrose, George F. R. Ellis and Stephen Hawking, on the other hand, started from Albert Einstein’s theory of general relativity and added notions related to space and time.
These measures allowed them to infer that time and space had a beginning that was finite and that corresponds to the origin of energy and matter.
The current Big Bang theory, combines principles of general relativity theory with several observations about changes in the position of galaxies. This combination allows to extrapolate the conditions of the universe in time.
Following the precepts of the Big Bang, scientists have found that the universe is expanding at a faster rate. This may be due to so-called dark energy.
What was before the big bang?
The short answer is:
nobody knows.
Longer answer:
The Big Bang is considered to be the beginning of the universe we live in. However, many questions surrounding the Big Bang remain unexplained.
For example, it is unknown whether time only came into being at the time of the Big Bang. Or whether there was time before the Big Bang. In the former case, the question ‘what was there before the big bang’ is of course meaningless.
By the way, nobody knows exactly what time actually is, so it may still take some time before this question is answered.
It is often assumed that the Big Bang not only represented the origin of matter and energy, but also the origin of time and space. Still, there are theories in which space already existed before the Big Bang. Some physicists even speculate about the existence of a complete universe before ‘our’ Big Bang.
In any case
If there was anything before the Big Bang, we will never be able to observe or measure it in our universe. As far as that is concerned, it may well be an academic question.
