Evidence of Big Bang
Today, we will talk three evidence of BIG BANG. The beginning of our universe, 13.8 billion years ago. I know you and I are here on Earth for twenty, forty, sixty or hundreds years. if you talk humanity far a few hundred thousand years if you talk about early humanoid species, far a few million years if you talk about earth itself it was born 4.5 billion years along with the Sun if we talk about the universe, then we are talking of a period a long time ago.
Now the question is how do we know that our universe started with the Big Bang?
Come let’s talk about today in this article. Is that what evidence do we have of the Big Bang?
What is Big Bang and First Evidence of Big Bang.
If you are talking at the beginning of the 20th century, say 1910, 1915 or 1920. Then I would be telling you that our universe is static and this was always like this as we see it, and it always existed. But in 1929, Edwin Hubble (in whose name is the Hubble telescope) observe that when you see the galaxies and you see any galaxy you note it is going farther away from you.
One interpretation of this fact can be that our Milky Way galaxy is in the centre of the universe and everything is moving away from us. But in reality, it is not happening this way. Instead whichever is galaxy you are, and you will feel that all the galaxies are moving away from you, what does it mean? According to Edwin Hubble.
How are universe is expanding now when we talk about the universe, a lot of things are counterintuitive it is usually difficult to think about it because we are not used to it so how do you imagine that expansion of the universe? Let’s take the example of a balloon if you take a balloon, what dots on it, and blow balloon. Now it seems that all those dots are moving away quickly from each other. No analogy is perfect, but you can imagine that our universe is the surface of the balloon. Now, from any dots you will see that other dots are moving away.
Astronomers, give an example of baking a cake, and if you have raisins on it when the cake swells, it seems that all the raisins are going farther away from each other, why is it? This is so because the dough or cake is expanding.
About the universe, we will say that the galaxies are expanding It means that the space between the galaxies is increasing. Now the question is that in what this universe is expanding. Because then we talk about expansion we ask in what? What is outside it? But here comes the counterintuitive things that there is no space outside the universe. Space is the property of the universe so when it is expanding it is creating, Likewise, there is no center of the universe.
As I was telling you about the expansion of the galaxy. In whichever spot you are, the universe seems to be expanding on every site. But the side-effect of the expansion is that if today the universe is expanding means the distance between different galaxies is increasing. ETA means that if you start going back in time, the distance between the galaxies was less than now. And if you keep on going a time will come when everything will be in one dot. The interpretation is called the big bang.
When you reverse it, that at one time, everything was very dense and is one dot. In a sense, we can say that our universe which is the three dimension space today was zero dimension at that time. What I am going to talk about now is a bit complicated, but I have to tell it. Which is that we do not know whether our universe is finite or infinite?
If our universe is infinite, it means that whatever distance you reduce between the Galaxies that dot will not be one dot but infinite dots if our universe is infinite.
Now how to understand it, we will talk about it some other time, but now I am saying only for clarification because we do not know whether how are universe is finite or infinite.
Second Evidence Of Big Bang
The Big Bang idea is present, and if you ask, where did the Big Bang take place. The answer is because we are a part of the universe the Big Bang took place everywhere. This place, that place were all a part of the big bang because we are a part of the dot. Expansion of the universe is not the only evidence of the big bang.
That reason is in 1940 century and astronomers or physicists Alfred Hoel along with some other man game an alternate theory, namely “ Steady State Universe”. He said that expansion is taken place in the universe, but the universe has always been expanding. There is no beginning to it. That is why the theory is called “Steady State”. It says that the density of the universe always remain as is today. To preserve the density theory, and because the universe is expanding the creation of a little matter was necessity. Only one atom in a few cubic light-years.
Now you will say matter, cannot be created or destroyed. Yes, you are correct. But Alfred Hoel said that it is a minute quantity of matter this law does not apply and breaks down on the scale of the universe. He said that if you object to my theory (creation of one atom, in cubic light years), then look at the Big Bang theory, in which the whole universe comes into existence, with the creation of matter. In fact, he took the word BIGBANG as an insult that what sort of theory is this that, the universe came into being due to the Big Bang. But the word BIGBANG stuck, and today we talk about this theory.
But the key evidence about the Big Bang theory was “Cosmic Microwave Background Radiation”.
When our universe started expanding, it was not an explosion, but it was an expansion, and when it started to expand there was a fall in the temperature. This we know from 9th & 10th grade Physics Gas Laws which state that whenever something expands its temperature falls.
This happened with our universe. In the beginning, the temperature of our universe was very high, because the density was very high. It was so dense that the creation of atom was not possible because electrons and protons could not meet and they were moving freely. Electrons and protons were so dense that even light (photons) could not escape, and it could not move freely and used to strike against the electrons or protons. Innocence you can say that our universe was “Opaque” at that time, this is also called “Plasma”.
When the universe kept expanding the temperature kept falling, and after about 4000 years of the beginning the temperature had fallen so much that the electrons and protons combined to form atoms. And as they combined the light of our universe (photons) starting flowing freely. This was the transition from the plasma to the gaseous phase. This is the prediction of The Big Bang Theory which says bad previous year, it was very dense and became less dense afterward. It also says that when the lights starting spreading for the first time, the temperature of the universe was about 1000° Kelvin.
You can assume that the temperature of our universe was like the temperature of the surface of any normal star. Our sun’s temperature is 500°. So the temperature of the universe was 3000 4000°.
The universe kept expanding and a prediction is the temperature of that light which started flowing freely. 4000 years ago, is 3° Kelvin today and the prediction was that it is the same temperature of any point in the universe if you recall temperature weather thermometer at any point of the universe, and the prediction was confirmed in 1965 by two physicists Arno Penzias and Robert Wilson.
They were actually working on microwave antennae at the AT&T Bell Laba and they observed that there was a particle of . background noise that didn’t disappear, Whatever day date to make it disappear. Then they realised that this detection confirms the temperature theory of the Big Bang.
In fact they both receive the noble prize for the discovery. The “Steady State Theory” was not able to predict the “Microwave Background Radiation”. This was a stunning discovery that this smooth background of our universe is based on 3° kelvin which is the temperature of our universe. Not only is that the background radiation is smooth, but it has a slight variation about a millionth of kelvin. If you see it’s map of the hot and cold in this background radiation this map will tell you that
This variation will after 4000 here, eventually from the glass is in the hot and cold spots. So the variation of a millionth of degree Kelvin maps formation, of the galaxies on today’s large-scale structure.
Third evidence of big bang
The third evidence is called “Big Bang Nucleosythesis”. At the beginning of the universe, the temperature was very high, but in the last few minutes, remember we are talking about 13.8 billion years in the past and we are saying that in a few minutes at the beginning of the universe, which is the only only proton, but The Big Bang Theory predict the fraction of Deuterium. Lithium, Helium and Beryllium in our universe. The universe was expanded and the temperature was falling, it made only these elements. Other elements of which we are made of such as carbon nitrogen, oxygen, I don’t etc were made in the stars.
The Big Bang Theory that our universe has 75% hydrogen and 24 to 25% helium. The rest of the elements are less than 1%. When astronomers measure the distribution they found that 75% is hydrogen and 24 to 25% is helium.
Result with Combine All Evidence of Big Bang
After seeing all the evidence, we know that the beginning of the universe started with a big bang. And when the expansion started, it was in a very dense state, and now it is less dense. It is remarkable we human who have been on the road for a little time can find out what happened 13.8 billion years ago. And the search and curiosity is appreciable.