As we have read in schools that in the early stage of earth or before we came into being, the dinosaurs walked in it. It is controversial to speak about the big bang, but we need to discuss it because the theory of big bang is a huge prediction and physicists/cosmologists are still on the verge to explain the phenomenon.
While recalling Big Bang theory that the universe began as a point of infinite gravity. Then, in trillions and trillions (10^-12) second, it exploded outward, expanded at a rate faster than the speed of light. Physicists name the phenomena as inflation. (This was an expansion of space itself, so it’s allowed to violate the rules.)
Now, what caused the Big bang is a bigger issue which is a very complex issue for the physicists working on it. For uttering a remark physicists need to solve the problem in steps. The biggest problem is the low entropy of the universe, a technical term for the disorder. Everything goes in the direction of disorder, never the reverse. But if that’s the case, the universe should be a uniform distribution of disorganized subatomic particles. How did atoms ever form molecules? How did clouds of gas and dust form stars, planets, and galaxies? The only explanation is that the universe had even lower entropy at its birth than it does today.
— NASA Goddard (@NASAGoddard) October 12, 2017
Researchers from Princeton University Robert Dicke and James Peebles proposed another model of Big Bounce, which says that the earlier universe collapsed into the singularity. The proponents say that our universe is infinite, going through a never-ending cycle of collapse and expansion. Again the critics claim that the principles of entropy don’t allow a universe to collapse into a singularity and out again. Critics also propose for new theories to be developed for bringing up the proposed model of Big Bounce. So, ultimately scientists revealed that there cannot be a singularity for the universe and Instead, all the energy in the universe was bound in the fabric of space called as the inflation hypothesis. This leads to a huge swell of energy in one patch of the field, which made it expand incredibly quickly. So ultimately this exponential growth spurt would leave evidence behind in the form of primordial gravitational waves — not the big ones discovered by LIGO in 2015, but tiny imprints in the cosmic microwave background that other projects (including the BICEP2 experiment) have been searching for.
The theory of multiverse (multiple universes) is an offshoot of the inflation hypothesis and says that the elements that lead to inflation also lead to the creation of a bunch of smaller, low-entropy universes. Although it would not be possible for us to explore the origin of the different universes, because, mankind has some limitations!!!!
As a concluding remark we can say that the probability for the beginning of the universe is still a hypothesis and since our cosmologists are working day and night to remove the barriers and laws for bringing out the conclusion is at the trending remark. Hope a strong and well-proposed hypothesis comes to break the enigma of the universe formation.