It’s ironic how a TV show which was named after one of the most significant theories of Universe creation is actually more popular than the theory itself. Well, it must have to do something with a rather odd name for a scientific theory. The Name Big Bang also started a misconception that the Universe was created with a “Bang…!” which is not at all what this theory is all about.
The Big Bang theory doesn’t really tell about how the Universe was started, it is something we are yet to figure out. Yet, what it does is, it addresses almost every question after that, considering that at the start the Universe existed as a Singularity. So what is a Singularity? It is again a theoretical concept which says Singularity is a small body with almost infinitely large mass and infinite density (Again, an assumption). These Singularities are mainly said to exist at the centers of black holes.
The Theory says that at the birth of the Universe there was a Singularity (Where it came from? We don’t know). The singularity was very small body with immense density and heat. The Heat as told by NASA could be up to 5.5 Billion degrees. At such high temperatures and pressures, the physical matter and the energy was all one and the same. As the time passed by, the Singularity started expanding and became cooler and cooler with time. The cooling of the core made the particles as electrons and neutrons appear. The Universe is said to have expanded millions of kms in just a second after its creation. As it further cooled, the particles combined to form stable environment and the first Hydrogen atom was formed. After that the Atoms were formed and 13.8 Billion years after we have planets, stars, humans and everything in the universe.
Now, even if this theory is based on numerous assumptions and yet unknowns, it is the most accepted theory for Universe creation till date. The fact that this theory was thought of was because of experiments based on cosmic energy radiations and Red Shifts. So, the scientists use some kind of cosmic radiations to view and study distant stars and galaxies. The observation that was made showed a red shift in the spectrum of distant galaxies and stars. What’s Red Shift? Red shift is phenomena where if a heavenly body is travelling away from earth, the light coming from it appears to be Red. This is because the relative motions between two bodies causes wavelength of light to stretch and Red is longest wavelength in visible spectrum. This experiment proved that the galaxies are further drifting apart and the universe is growing in size as you read this post. This gave rise to the Big Bang theory saying that if universe is drifting apart with time, it means at the beginning of the time it was all just a singularity. And surprisingly enough the theory follows all the Einstein’s laws of relativity.
As George Shaw quoted “Science never solves one problem without creating 10 more”. The Big Bang theory rose more questions than it answered and many of them were attempted to answer. So assuming that singularity existed at the birth, what was before that? This is one of the most popular question having multiple answers. The theory suggests that the Time started when Universe was created, so there is no “before” the Big Bang. Some alternate theories also go around like, this big bang is just a chain and a totally different universe existed and died before this big bang and another universe will form after death of this Universe. Theory suggests that the Universe expanded, what it expanded in? Nothing. It expanded to become itself, there is no space out of the universe, there is nothing out of the universe. Universe is all there is. And another favorite question, What is the future of the universe? How much will it expand further? Well, no one really knows answer to this but, as of now, Universe is expanding and cooling at the same time day by day. There are theories that suggest various ends, some say it will expand infinitely and then become a cold dark place and end. Some say it will expand up to a certain distance to which gravity will allow it to and then stop and become stable. Some say it will expand to its maximum and then start contracting again starting the reverse big bang and end the universe.
There are yet so many unanswered and unknown things and yet, we try and test the limits of science and try to explain everything. But, is it really possible to explain everything with Science? We are nowhere near that yet.