People know very less about big bang that it was a point of creation of universe , i am going to explain a little more about it. The Big Bang Theory is an effort to explain what happened at the very beginning of our universe. In mid 20th century most of the scientists thought of universe is infinite or ageless. Prior to that moment there was nothing, during and after that moment there was something- our universe. But how can something come out of nothing ,let's explore. Before that we can ignore beginning part i.e. before singularity though I am going to discuss it at last. Our universe came into existence out of singularity around 13.7 Billion years ago which is the age of our universe according to NASA.
What is singularity?It is truly a concept that boggles the mind because it defy our current understanding of Physics. Singularity thought to exist at the core of black hole. In simple grammar singularity comes from the word singular that means “one subject is acting”. Now in terms of black holes a point where everything gets unified( becomes one) i.e. when I am saying one it means a number. But let me explain from where does this singularity come from. As we know Black hole is region of space having a gravitational field so intense that no matter or radiation can escape. So inside a Black hole space, time and matter get unified( become a number). And even 4 fundamental forces( Gravity, Electrostatic, strong and weak nuclear force) fuse into one particular force.
We know black holes are formed when a star get collapsed into its center and all the stuff of star will reduce to that very tiny point, that occupies no space at all and still very heavy according to general relativity. How to understand something that occupies no space at all and still very heavy ?Is it practical, logically it is something to be questioned but we have the information of the died star(the star which collapsed into black hole). That information is what makes singularity heavy and information is described by a number. If we talk about singularity, singularity is a small box of space and time which possess information of objects, its objects can be black hole or can be Universe itself. So now you might be somewhere more clear about what is singularity. In other words we can say that singularity maybe called as a point of unification and fusion that preserve the information of all the black holes and universe itself as a number.It’s a zone of infinite density.
WHAT HAPPENED AFTER BIG BANG
Initially our universe is thought to have begun as an infinite small, infinitely hot, infinitely dense, something- a singularity. What all was a hot dense environment in which energy manifested itself in particles that existed only for tiniest glimpse of time , from gluons Pair of quarks were created which destroyed one another perhaps after giving up with more gluons, these found other short lived quarks to interact with forming new quark pair and gluon again. Matter and energy were not just theoretically equivalent, it was so hot that they were practically the same stuff. Somewhere around this time matter won over antimatter. Somehow for one billion and one matter particles there were one billion antimatter particles formed. And now instead of one ultimate force in universe then there were several refined versions of it acting under different rules. By now universe has stretched to a billion kilometer diameter which lead to decrease in temperature. The cycle quarks being born and turning back to energy suddenly stops.And Quarks begin forming new particle hadrons like proton, neutron.
There are many many combinations of quark that can form all sort of hadrons but very few are reasonably stable for any length of time. Till now only 1 seconds has passed from the beginning of everything. The universe which is now grown to hundred million kilometre is now old enough to allow most of neutron to decay into proton and form first atom -”hydrogen”. Atoms formed out of hadrons and electrons making stable and electrically neutral environment. Some call this period as dark age because there were no stars and hydrogen gas didn't allow visible light to move around. But what is the meaning of visible light Anyway when there is nothing live yet that could have eyes. When hydrogen gas clumped together after million of years and gravity put it under pressure stars and galaxies began to form. The radiation dissolved stable hydrogen gas into plasma that still permeates the Universe today and allows visible light to pass. Finally there was light.
BEFORE THE BIG BANG
But what about the past we didn't talked about. what happened right at the beginning? This part can be defined as big bang. We don't know at all what happened here. At this point our tools breakdown, natural laws stop making sense, time itself becomes wibbly wobbly. To understand what happened here we need theory that unifies Einstein's relativity and Quantum Mechanics something that countless scientist are working on right now. But its not over yet rather this leaves us with lots of unanswered questions.
Were there universes before our own? if yes it might be the big bounce. Is this the first and only universe? what do you think.
EVIDENCE FOR THE THEORY
1. According to Hubble's Law of Edwin Hubble galaxies appear to be moving away from us at speeds proportional to the distance. He discovered this phenomenon in 1929. This observation supports the expansion of universe and suggests that the universe was once compacted .
2.If the universe was initially very very hot as the Big Bang suggest we should be able to find some traces of this heat. Two Radio astronomers Accidentally discovered cosmic microwave background radiation(CMB) because it more visible in radio frequency. The CMB is the thermal radiation left over from the time of recombination in Big Bang . The CMB is fundamental to observation in cosmology because it is the oldest light in the universe dating to the epoch of recombination.
3.Finally the abundance of light elements hydrogen and helium found in the observable universe are thought to support the Big Bang model of Origins.
MOST COMMON MISCONCEPTIONS
1. There are some misconceptions surrounding the Big Bang Theory for example we tend to imagine it as a giant explosion. But it wasn't an explosion( most frequent misconception),There was( and continues to be) an expansion.
2. Another misconception is that we tend to image the singularity as a little Fireball appearing somewhere in space. But the truth is space didn't exist prior to the big bang, it was space stretching all at once. Universe didn't expand into anything rather it was space expanding into itself. Universe cannot expand into anything as it has no borders so all of it is universe. The singularity didn't appear in space rather space began inside of the singularity. Prior to the singularity nothing exists space, time, matter, energy- nothing.
What started the big bang or did it just occurred naturally based on Laws we don't understand yet? We don't know and maybe we never will. Science is all about experience.So let's keep on experiencing it until there are no more questions to ask.
Thank you for reading this post and I will soon come up with more posts on cosmology please follow and comment if you find something lacking.
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