Big bang theory
A thought that how the universe started has arised in many people’s minds and the answer we get is the term big bang, but what is big bang ? how a small dot becomes such a large thing within secs. We are going to answer all such questions today. Scientists have determined that our universe is 13.82 billion years old but how they calculated we today are going to tell you everything related to it so let’s dive right in.
What is the Big bang ?
The Big bang theory explains that before 13.82 billion years the complete universe was condensed in a small point of infinitesimal small singularity. And then suddenly a large explosion expansion occurred due to which the point started to expand outwards faster than the speed of light. This period was called cosmic inflammation.
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| Big bang, Image source : Hubble |
The Big bang theory was introduced by an astronomer Georges Lemaitre in 1927 in which he explained how the universe was born. In this “Infinitesimal small singularity” means that it had infinite density, infinitesimal volume and space and time was completely distorted and completely unstable. And all this cosmic expansion occurred in a 10-32 of a sec. And it thus explains the formation of the universe.
Timeline
Singularity
At the start of the universe the complete universe was condensed into a small infinite singularity point with infinite density, infinitesimal volume, Complete space and time distorted, it was too hot. And completely unstable. This is the earliest point of the universe we know.
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| Timeline of big bang, Image source : Science sparks |
At the singularity point it was denser than the requirement of density for formation of black hole, but it did not become black hole because matter at that stage was much evenly distributed with no density gradient due to which it did not become a black hole.
Expansion
It is not known till now what was the exact reason for the expansion of the universe but it is believed that it was due to the instability of the point. Due to this instability there was a sudden expansion of the universe which started to cool down and the heat came to a measurable point. Then the reaction of barogenesis started which then reduced the number of anti-matter and increased the no. of matter in the universe.
Cooling and formation
When the universe started to expand with the speed of light, the density along with temperature started to drop down but still the temperature of the universe 5.5 billion celsius. The universe then came to the point of when were cosmic inflammation stopped and slightly denser region of universe started to attract each other by gravitational force and started to form various heavenly bodies like stars, galactic clouds, galaxies
How old is the universe ?
Until 2013 it was thought that the universe is 13.7 billion years old but in 2013 Planck's observation by NASA’s CMB(Cosmic background explorer) found that the universe is 13.82 billion years old, rather than 13.7.
You must be wondering how it must be calculated ?, The perfect age of the universe is determined by measuring the rate of expansion of the universe.
Is the universe still expanding ?
Yes, The universe is expanding but it is expanding faster with time. It is moving with co-moving distance; it means that the universe is not expanding outwards and filling empty space but instead the space fabric is only expanding.
For example there are two galaxies galaxy A and galaxy B. First the distance between two galaxies is 15 light year but after 1 million year the distance between the galaxies is 150 light year. This thus explains that the space fabric is only expanding. This was told by Georges Lemaitre in 1927 and he also found that galaxies are going further due expansion of the universe.
And with time the speed of expansion is also increasing. This tells us that along with time we will not be able to observe any of the galaxies as the light of galaxies will not be able to reach till us.
Formation
How stars and galaxies were formed ?
When the cosmic inflammation suddenly and mysteriously stopped then things like atoms and started to form from small and tiny particles. And these atoms started to group which formed molecules and molecules formed stars and large clusters of stars formed galaxies. And this all happened in the first second of the universe.
Then the stars also started to produce various types of atoms by nuclear fusion which formed more new types of stars. The stars which were formed at first were much bigger than the stars we see today. At the same time galaxies were also colliding with each other which caused formation of bigger galaxies.
How planets were formed ?
When many stars were formed. The star's life cycle started and old stars started to die and new stars were formed. The residue of dead stars formed asteroids of various sizes. The large and small asteroids started to collide with each other and formed much heat when combined with each other.
This collision then formed planets and dwarf planets. The hot universe then started to cool down after expansion. This caused the leftover gases, dust, rocks to condense and form comets.
How Black holes were formed ?
During the start of the universe stars formed were massive in size. Average life of a star lies between 10 billion years to 10 million years. At the end of their life the core of the star starts to collapse in itself. This causes a large explosion called a supernova explosion.
And when the explosion occurred all the mass of the star then collapses into the core of the star and thus forms the black holes. Black holes are the heaviest and densest object of the universe with incredibly strong gravitational pull which doesn't even allow light to pass through it.
Other theories related to formation of universe
Dark matter
During 1975 to 1980 many physicists found that there was not enough visible matter available in the universe to form the apparent gravitational strength between the galaxies. And thus a point was raised that during the formation of normal matter dark matter was also created.
The dark matter occupies 90% of space present in space. As its name Dark matter does not emit light and does not interact with normal matter. But dark matter is still hypothetical as it is still not proven that dark matter exists in the universe.
Multiverse
There is one theory related to the universe called the Multiverse theory. It suggests that there is an infinite universe present and collectively they are called Multiverse. And each universe is formed after one universe dies and it is said that our universe started with the death of the universe which existed before us.
According to the Multiverse theory each universe is a bubble and there are infinite bubbles holding their own universe. Multiverse is beyond human mind capacity and if it existed there would be the same person like you in another universe but instead he would be the richest man in that universe. This is just an example with an infinite universe there would be infinite possibilities about you and all of us.
Conclusion
So this was all for today, hope so that you would have understood the formation of universe according to Big Bang theory. Important point of today’s post were -
- Big bang is a theory introduced by an astronomer Georges Lemaitre in 1927.
- The Theory explains that before 13.82 billion years the complete universe was condensed in a small point of infinitesimal small singularity.
- point started to expand outwards faster than the speed of light.
- the CMB did a detailed research and found that the universe was 13.82 billion years old.
- galaxies are going further due expansion of the universe.
- atoms started to form from small and tiny particles.
- atoms started to group with each other and formed stars and galaxies.
- The residue of dead stars formed asteroids of various sizes.
- This collision of asteroid then formed planets and dwarf planets.
- All the mass of the star then collapses into the core of the star and thus forms the black holes.
- Black holes are the heaviest and densest object of the universe.
- At the start of the universe the complete universe was condensed into a small infinite singularity point.
- there was a sudden expansion of the universe which started to cool down and the heat came to a measurable point.
- When the universe started to expand with the speed of light, the density along with temperature started to drop down.
- slightly denser region of universe started to attract each other by gravitational force and started to form various heavenly bodies.
- And dark matter occupies 90% of space present in space.
- there is an infinite universe present and collectively they are called Multiverse.
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