Looking at the night sky we have always wondered- “How big is this universe? Firstly, to answer this question, the universe is not only bigger than what we imagine but it’s bigger than one can ever imagine. But, the universe has not been this large since forever. According to Edwin Hubble, our Universe is expanding faster than the speed of light which implies that it had to be very small at the beginning to expand in the first place. This gave rise to the most commonly known theory which is known as The Big Bang Theory. It states that the whole mass of the universe was concentrated in a very small area with infinite density and extremely high temperature. This highly dense particle that contained all of the universe’s mass went under an explosion, which marked the beginning of the Universe and Time.
Though the theory of the big bang is a hypothetical concept, it was still widely accepted by scientists all over the world after the discovery of Cosmic microwave background(CMB) radiation in the year 1964. It is considered to be the echo of the big bang that gave proof of a large explosion around 14 billion years ago. But, the big bang still being a theoretical concept, has many worthy competitors with different convincing hypotheses on the birth of the universe.
Here are four of the interesting Alternatives to the Big Bang Theory:
1. Quasi Steady-state theory
Steady-state theory can be considered as a direct contradiction to the big bang theory. It suggested that the universe never had a beginning and has existed forever with a uniform density. Due to various drawbacks of this theory, it was later updated to Quasi steady-state theory. It stated that as the universe expands there are packets of matter which are constantly being created to maintain the density of the universe. But this theory wasn’t able to convince scientists as effectively as the big bang theory. The data from CMB proved that a huge explosion had happened billions of years ago(around 14 billion years) which marked the beginning of the universe.
2. Mirror universe theory
The mirror universe is a very hypothetical yet interesting alternative model to the big bang. It states that during the big bang two universes were born, one proceeding forward in time and the other proceeding backwards in time. It implies that the time of our universe proceeds from its birth to death but also proceeds from death to its birth in the mirror universe. The movie Tenet gives the best example of such a model where the entropy of the objects is reversed which makes them run backwards in time.
3. Digital simulation
Technology in the 21st century has enabled humans to develop and control a simulation of various physical aspects of our surroundings through smart computers. The advancement of technology will ensure a steady development in the domain of simulations possible by humans. Sometime in the future, there is a chance of this domain to expand and make it possible for humans to simulate a whole universe that can be controlled by using varying initial and final conditions. Yet, this additionally questions our reality as a universe that is not recreated. Scientists have wondered what if our universe is also simulated by some highly intelligent civilization and our fates are predetermined by them. This theory of predeterminism is also supported by the concept of quantum entanglement. Here, information travels faster than the speed of light violating the rules of the theory of relativity. One of the possible reasons for this phenomena is predeterminism where the spin of the entangled electrons is determined at the beginning of the universe itself.
4. Multiverse theory
The theory of multiverse states that there is an infinite number of universes that are being born due to fluctuations in dark energy leading to multiple big bangs like explosions. Many such universes created due to explosions cannot sustain themselves and eventually collapse to form a black hole. But some Universes like ours had an explosion that was sufficient enough to expand itself and it will expand till all the matter in the universe is separated from each other creating a space of dark energy, wherein again the process of big bang happens and new universes keep on forming constantly.
Apart from these, there are many other exciting hypotheses such as inflation theory, infinite universe theory, gravity rainbow, etc. which though had a good base and logic but failed to beat the big bang theory which is still the most widely accepted theory in the world. But the big bang theory is also a hypothesis that hasn’t completely been proved and understood yet, so, the origin of the universe is still a mystery to mankind.
Similar to the birth of the universe, scientists have also predicted and put forward various hypotheses for the death of the universe. To know more about them stay tuned to the STARGAZING MUMBAI website.