Have you heard of the big bang theory? No, not the TV serial; the actual theory. Well let’s see.
Let’s try something. Imagine the Universe; the vast and never-ending blackness that surrounds us; the space in which we all dream to go as astronauts. Now imagine that there is nothing; absolutely nothing, no stars, no galaxies, no solar systems and no planets. Can you imagine it?
So how did our Universe come into being? How can something come for nothing? How was our universe born from nothing?
Well it wasn’t nothing. The Big Bang theory is the most accepted scientific theory of the origin of the universe. It tells us how and from what our universe was born.
What is Big Bang Theory
This Theory suggests that all of the energy, matter and empty space in our universe was condensed or packed into a tiny hot spot no bigger than an atom called the Singularity. All the mass of our Universe was concentrated in this dense hot ‘dot’. Then all of a sudden it inflated or blew up to form our universe. 13.7 billion years ago this burst created time, space and energy. This space and energy started stretching everywhere all at once.
In 1925, it was Edwin Hubble who first noticed and proved that our universe is expanding by noting that galaxies were going further and further apart. So if everything is expanding and continuously going far away from each other it means that it had to start at a certain point. Researchers theorized that it all would have started with an explosion of an infinitely small and hot point. At the time this idea was jokingly referred to as ‘The Big Bang’. But as scientists found more and more evidence for this theory, the notion and the name actually stuck! And that’s how this theory got its name.
When the Singularity, the dense hot point burst and began expanding, it started very small and quickly expanded into the size of a football. One millionth of a sec after the big bang the universe cooled down to 10,000,000,000 degree Celsius. Particles called Gluons fused to form Quarks, but they couldn’t hold together because of the immense heat and that too destroyed one another after giving out more gluons. It was so hot that matter and energy was the same thing. There was no difference. Everything that was there was the same.
Hundred seconds after the big bang, quarks which are the building blocks of atoms were forming neutrons, electrons and protons but it was too hot for electrons to join and form atomic nuclei, so the universe was just a sea of subatomic matter, which is the matter that when brought together forms an atom.
What are Quarks?
The expansion of the universe lead to a decrease in the temperature. The more it expanded the more the temperature dropped and 3, 00,000 years later, the universe had cooled down enough for Hydrogen, the most basic element from which everything in the known universe is made up of, to form.
Many million years after the big bang gas clouds, stars, galaxies, planets, and solar systems began to form.
All that we know today of how the universe came into being is because of the work of particle physicists. One can learn about the beginning of the universe by recreating the hot, dense conditions that existed at the beginning of time in a laboratory. This is done with the help of the Hadron Collider which is a particle accelerator that takes two atoms and coming from very high speeds smashes them together. By seeing the effects after smashing these particles together, scientists can speculate, or guess what happened all those billions of years ago.
But what happened before the big bang?
As discussed earlier, the universe came into being from the Singularity. It was a time at which the laws of physics or even time did not exist. The theory of the Big Bang has been a source of many theories of what may have happened before our universe existed.
Some scientists say that the Big bang may have been a big bounce. This also comes from the fact that our universe is expanding. Another universe, after billions of years of expanding collapsed in on itself and formed a single massive black hole eventually collapsing into the singularity that expanded to form the universe that we currently exist in. It may have been happening forever and will continue to happen forever, i.e. our universe too will collapse in on itself and another universe will form.
Another hypothesis, or idea is that there is an infinite number of universes. It is called the multiverse theory. There could be many other universes just like ours and all may be expanding and pushing other universes further away.
Some say that if two of these Universes collide it could create a cataclysmic event, a big bang and create an entirely new universe. It is even possible that our universe came into being the same way.
Our universe is an interesting and majestic place and understanding its origins helps us see more of its beauty and splendor.