Post by rommel323 on Jun 14, 2021 6:16:34 GMT
The Birth of Universe - Big Bang and it's alternatives
The universe is filled with mystery. Everything, even the universe itself is a mystery. It's formation, the celestial bodies, the probable ends, all are a mystery which we still can't figure out. But that doesn't mean that we can't let our imaginations run wild. Even the complex equations which astronomers talk about space and time is also based on our assumption.
A mind blowing fact - The universe was born at no place and no time! This is because time and space and time originated only after big bang. The universe started it's journey of 13.7 billion years (it is really a lot of time) ago, from a single point. This point contained infinite gravity and density and energy. Yes! a single point from which everything around us was created. Then, this extremely dense point exploded with unimaginable force, sent the matter into all possible directions. This is known as the big bang. But, there is no sound of bang during the big bang as sound can travel through a media and there was none - neither solid, liquid nor gas (the atomic particles had not been created yet to enable sound to pass). This is the widely accepted theory of the origins of big bang.
Our Universe is expanding even now. It was smaller when you started reading this post than now. It is expanding at the speed of anywhere from 68km to 74 km per second. Another interesting fact is that some scientists are beginning to unearth evidence that the reason our brains are hardwired to react to certain tonal configurations (minor chords, sound sad, etc.) has something to do with the overtones of the universe, formed by the inflation of the universe following the Big Bang.
There are some other alternatives to the big bang. The main rival to the big bang in the older times was the steady state universe, which states that the universe does not have a beginning, nor an end. Though the universe keeps on expanding, it's density remains the same. The galaxies, planets, and other forms of matter are always being created, and since the density is the same, the old ones are becoming unobservable with new creations. This theory was proposed by Sir James Jeans in 1920 and was re-established in 1948 by Hermann Bondi and Thomas Gold.
Another one is that our universe is formed beyond the event horizon of the black hole. But since we cannot cross the event horizon of the black hole, it cannot be proved. Some of the people, letting their imagination run real wild, proposed that our universe is a computer simulation. But scientists have got conclusive evidence that if our universe was a computer simulation, then that computer must control every small movement from an electrons to huge stars. Also, scientists have calculated that the record the information of a few electrons, all the atoms of the universe is not sufficient and that it's complexity increases with a every few electrons added.
The picture explains the main difference between Big bang and steady state theory
What were the conditions of our universe, just after the big bang? Fortunately, we have a lot of predictions on this topic.
According to the Big Bang theory, the universe at the beginning was very hot and very small, and since then it has been expanding and cooling down since then and even now. Early universe was a very dense, dense enough to make a black hole. Remember that a black hole is formed when large amounts of matter is fused into a small space. That is the reason why a black hole is dense.
The Universe, 10^-43 seconds after it's creation, was extremely hot, about 10^32 degree Celsius. Here, the four fundamental forces were created as one namely -
1. Gravitational force - the weakest force. Has infinite range of action and all matter is affected by it throughout the universe. Due to the cooling of universe, it gets separated first.
2. Electromagnetic force - the second weakest force. It also has a range of infinite range of action and it keeps atoms and molecules together. Also responsible for the properties of matter. It was the last one to separate, during the the time when temperatures cooled enough to allow quarks ("building blocks" of subatomic particles "not subatomic particles".) and gradually, hadrons (subatomic particles) to form.
3. The weak nuclear force - Do not go by it's name as the weakest of the four. It is strong but it's force does not extend throughout the universe. Also, it is responsible for the fusion reactions and radioactive decay (process by which an unstable atomic nucleus loses energy by radiation).
4. The Strong nuclear force - It has the strongest force, but shortest range, keeping the nucleons (protons and neutrons) together. It gets separated after the gravitational force, when the universe starts to expand greater than the speed of light. During this time, temperatures dropped by a factor of 1,00,000.
Now, all of this, starting from the big bang, happened from 10^-43 seconds to 10^-6 seconds (the time when quarks were formed) By the time the universe was 1 second old, it had expanded to a size about a thousand times the size of our solar system, and the temperature dropped to about ten thousand million degrees. During this time, first quarks, then hadrons, then leptons (particles not affected by strong force) dominated the universe as the most common type of matter.
This kept on changing because antimatter of quarks, hadrons, leptons kept annihilating each other. Now, something extraordinary happened, which changed the entire destiny of the universe and also, made the universe, in the way we know now.
The universe is filled with mystery. Everything, even the universe itself is a mystery. It's formation, the celestial bodies, the probable ends, all are a mystery which we still can't figure out. But that doesn't mean that we can't let our imaginations run wild. Even the complex equations which astronomers talk about space and time is also based on our assumption.
A mind blowing fact - The universe was born at no place and no time! This is because time and space and time originated only after big bang. The universe started it's journey of 13.7 billion years (it is really a lot of time) ago, from a single point. This point contained infinite gravity and density and energy. Yes! a single point from which everything around us was created. Then, this extremely dense point exploded with unimaginable force, sent the matter into all possible directions. This is known as the big bang. But, there is no sound of bang during the big bang as sound can travel through a media and there was none - neither solid, liquid nor gas (the atomic particles had not been created yet to enable sound to pass). This is the widely accepted theory of the origins of big bang.
Our Universe is expanding even now. It was smaller when you started reading this post than now. It is expanding at the speed of anywhere from 68km to 74 km per second. Another interesting fact is that some scientists are beginning to unearth evidence that the reason our brains are hardwired to react to certain tonal configurations (minor chords, sound sad, etc.) has something to do with the overtones of the universe, formed by the inflation of the universe following the Big Bang.
There are some other alternatives to the big bang. The main rival to the big bang in the older times was the steady state universe, which states that the universe does not have a beginning, nor an end. Though the universe keeps on expanding, it's density remains the same. The galaxies, planets, and other forms of matter are always being created, and since the density is the same, the old ones are becoming unobservable with new creations. This theory was proposed by Sir James Jeans in 1920 and was re-established in 1948 by Hermann Bondi and Thomas Gold.
Another one is that our universe is formed beyond the event horizon of the black hole. But since we cannot cross the event horizon of the black hole, it cannot be proved. Some of the people, letting their imagination run real wild, proposed that our universe is a computer simulation. But scientists have got conclusive evidence that if our universe was a computer simulation, then that computer must control every small movement from an electrons to huge stars. Also, scientists have calculated that the record the information of a few electrons, all the atoms of the universe is not sufficient and that it's complexity increases with a every few electrons added.
The picture explains the main difference between Big bang and steady state theory
What were the conditions of our universe, just after the big bang? Fortunately, we have a lot of predictions on this topic.
According to the Big Bang theory, the universe at the beginning was very hot and very small, and since then it has been expanding and cooling down since then and even now. Early universe was a very dense, dense enough to make a black hole. Remember that a black hole is formed when large amounts of matter is fused into a small space. That is the reason why a black hole is dense.
The Universe, 10^-43 seconds after it's creation, was extremely hot, about 10^32 degree Celsius. Here, the four fundamental forces were created as one namely -
1. Gravitational force - the weakest force. Has infinite range of action and all matter is affected by it throughout the universe. Due to the cooling of universe, it gets separated first.
2. Electromagnetic force - the second weakest force. It also has a range of infinite range of action and it keeps atoms and molecules together. Also responsible for the properties of matter. It was the last one to separate, during the the time when temperatures cooled enough to allow quarks ("building blocks" of subatomic particles "not subatomic particles".) and gradually, hadrons (subatomic particles) to form.
3. The weak nuclear force - Do not go by it's name as the weakest of the four. It is strong but it's force does not extend throughout the universe. Also, it is responsible for the fusion reactions and radioactive decay (process by which an unstable atomic nucleus loses energy by radiation).
4. The Strong nuclear force - It has the strongest force, but shortest range, keeping the nucleons (protons and neutrons) together. It gets separated after the gravitational force, when the universe starts to expand greater than the speed of light. During this time, temperatures dropped by a factor of 1,00,000.
Now, all of this, starting from the big bang, happened from 10^-43 seconds to 10^-6 seconds (the time when quarks were formed) By the time the universe was 1 second old, it had expanded to a size about a thousand times the size of our solar system, and the temperature dropped to about ten thousand million degrees. During this time, first quarks, then hadrons, then leptons (particles not affected by strong force) dominated the universe as the most common type of matter.
This kept on changing because antimatter of quarks, hadrons, leptons kept annihilating each other. Now, something extraordinary happened, which changed the entire destiny of the universe and also, made the universe, in the way we know now.
Matter vs Antimatter
What is the greatest war ever known to humanity? Is it World War 1? or the second one? Maybe the cold war or some other one. But, what if I told you that the greatest war ever, was not between humans, was before humans, earth, solar system, milky way galaxy, atoms and even before subatomic particles formed!
The war was between Matter and Antimatter. What is matter? Matter is nothing but those which occupy space and volume. Everything present around you is matter. Even you are made up of matter. Antimatter is a totally different thing. It is just diametrically opposite to matter. As I have already explained before, antimatter is like -1 and matter is 1. If we add -1 and +1, we get 0. It is the same in this case, except that it releases a huge amount of energy.
This image explains the difference between Matter and Antimatter, except that even their spins are opposite.
Matter is made of Protons, Neutrons and Electrons but Antimatter is made of Positrons, Antiproton and Antineutron. Also, remember that these particles spin in the opposite directions. How much energy is released exactly in these reactions? Well, if 1 kg of matter reacts with 1kg of antimatter, it will result in the production of energy of about 17200 Nagasaki nuclear bombs! Phew! that is a lot of energy.
Now coming to the war, Matter vs Antimatter, it happened immediately after the Quark Epoch. This phase is known as the Hadron Epoch. It is said that there are equal amounts of matter and antimatter during the formation of the universe. Then why is matter dominating the universe? Here comes the baryon asymmetry or the matter-antimatter asymmetry. This states that due to the previous phases during the formation of the Universe (Plank Epoch, Grand Unification Epoch, Electroweak and Quark Epochs), it seems that a slight misbalance between matter and antimatter happened. Now during the hadron epoch, the matter and antimatter collided and kept on annihilating each other.
Imagine 17200 Nagasaki nuclear bombs blasting in every direction possible around you continuously, releasing large amounts of energy! That was happening exactly between 10^-12 to 10^-5 seconds after the big bang. Exactly how much misbalance is given by the figure 50 in 100 crore or 1 billion. That is what exactly known as the baryon asymmetry.
Now you might think that this figure is very less, but that was sufficient to create the universe. And then, 20 minutes after the big bang, the universe was not hot enough to enable nuclear fusion. The Early universe was filled with radiation, but after about 47,000 years, it became matter dominated and then after about 1,00,000 years, the first molecule helium hydride is formed and after 3,70,000 years, neutral atoms formed and the universe became transparent. Until this time, the universe was opaque.
Between about 10 and 17 million years the universe's average temperature was suitable for liquid water 273–373 K (0–100 °C) and there has been speculation whether rocky planets or indeed life could have arisen briefly, since a tiny part of the universe could have had different conditions from the rest.
At some point around 200 to 500 million years, the earliest generations of stars and galaxies form (exact timings are still being researched), and early large structures gradually emerge, drawn to the foam-like dark matter filaments which have already begun to draw together throughout the universe. The earliest generations of stars have not yet been observed astronomically. They may have been huge (100-300 solar masses) and non-metallic, with very short lifetimes compared to most stars we see today so they commonly finish burning their hydrogen fuel and explode.
The Universe has remained the same from 1 billion years to 12.8 billion years and will be so for many billions of years into the future. Uncertainties in the current knowledge means that we cannot predict the future after a hundred or so billion years.
