Why is Big Bang the most accepted Theory? | The Born of the Big bang Theory | The Big Bang Theory Part 2

It sounds great! Well, no one knows how the big bang happened and we will not be knowing about it. So in this session, we will know why Big Bang is the most accepted theory. Well, we'll be seeing some of the proofs of the Big Bang. By not wasting much time let's get started...

You can see my previous post on the Big Bang Theory to get clear about this concept of proof of the Big Bang: How was the universe formed? The Big Bang Theory Part 1

The Invention of Telescope & the Proof of Heliocentric Theory

Everything started in 1608 when a Dutch eyeglass maker, Hans Lipperhey, invented a device that can magnify any object three times; this was how the telescope was formed. In 1609, an Italian astronomer, physicist, and engineer, Galileo Galilei made his first telescope and saw space. This invention was one of the biggest human inventions that were going to change the whole history. For his invention of the telescope, Galileo was named the father of the telescope.

 

Galileo Galilei

When Galileo observed that in space some celestial bodies which are planets like the Earth, are revolving around but not around the Earth but around the Sun. He also supported the Heliocentric Theory made by Nicholas Copernicus and told that our Earth is not the center of the Solar System in fact The Sun is the center of the Solar System. But the church disagreed with this theory and imprisoned Galileo for his whole life. In 1642 Galileo Galilei died in the prison. The church banned all Heliocentric books and the books related to it but the truth cannot be hidden. Just wit, what is this Heliocentric Theory? The heliocentric theory is an astronomical model in which Earth with other planets revolves around the Sun at the center of the Earth.

The rise of Mount Wilson Observatory and Edwin Hubble

With time, we improved the telescope and discovered many new planets. At the beginning of the 20th century, Mount Wilson Observatory was launched, and at that time this was the biggest observatory. This observatory was made by American Astronomer George Ellery Hale. His mission was to find out what was outside our Galaxy. Hale put the biggest telescope of that time i.e., the 100-inch telescope and finally in 1917 this telescope was opened. With this telescope, scientists saw many things. They saw many shining clouds of different colors and sizes. Some were spiral, some circular. Well, these were nebulas but at that time nobody knew about them. Some astronomers believe that some of these nebulas are situated at the corners of our galaxy and they thought that it can be an island universe. Hale invited many astronomers over the world to identify those objects.

Edwin Hubble

One of these astronomers was Edwin Hubble. He was a good observational astronomer and on nights he studied the nebulas present over space.  One of the nebulae which draw Edwin's attention towards it was The Andromeda Nebula. He thought that this nebula was a galaxy and to prove this he had to measure its distance from the Earth and that was not too easy. Finally, by using some methods Edwin measured the distance from the Earth. Well, he estimated that Andromeda is 800,000 light years away (real distance: 2,537,000). This means that Andromeda is outside our Galaxy and was another Galaxy. And after this Hubble discovered many galaxies and also proved that those nebulas which were spiral, circular and irregular were also galaxies.

The Born of Big Bang Theory

After all these discoveries Hubble discovered a surprising thing, he saw that all the galaxies in the universe are going away from our galaxy. Well, this discovery was already seen by an American Astronomer, Vesto Slipher but it wasn't proven. Slipher saw that the nebulas which were proved galaxies were going away from each other. Hubble saw that the galaxies which are present far from our galaxy were going farther from us i.e., the universe is stretching. Edwin Hubble's discovery was one of the important discoveries in astronomy and it meant that the universe is continuously stretching and getting bigger and bigger. Now, the question which arose to all the scientists, and I hope it had also arisen to you is that Why? Why is the universe going on stretching and stretching? Well, we don't know the answer to this question to date but I hope that this will the discovered soon. With this question, another question was also rose and it was, by what is this universe stretching? Hubble thought that if the universe is stretching then it might have been contracted at any time. And with this question, the Big Bang Theory was born. 

Well, to prove this Big Bang Theory we needed different types of telescopes from which we can see the electromagnetic waves. The visible light is a small part of the electromagnetic wave which we can see from our eyes. With the increase in wavelength, the electromagnetic waves move from gamma rays to microwaves and then move to radio waves. Well, we cannot see these rays from our eyes but we can see many things present in the universe which were not seen by the radio waves.

The Proofs of the Big Bang

In 1964, Astronomers Arno Penzias and Robert Wilson were working on a new radioactive telescope. The antenna present in this telescope could observe the microwaves and radio waves coming from space. They thought that by this they could see the light shine produced by the Milky Way Galaxy.  When they moved the telescope towards the empty space, where nothing should be there but they got the microwave signals which stated that, there was something hot. Well, there was nothing. Then why was that part of space hot? To find this, they moved the telescope in all directions but the signals were coming from all directions. They thought that this was a mechanical issue so they checked the telescope but the signals were being received. This showed that the temperature of empty space was 3 degrees high whereas it should be 0. These two scientists didn't know what was but accidentally they had discovered the proof of the Big Bang. The microwaves were the afterglow of the Big Bang which can be seen now also. If we take off all the stars in the sky and make it dark, we can see a light red shine, which is the light produced during the Big Bang, and this light is only present all over the universe but in the form of microwaves.  And for this discovery, Arno Penzias and Robert Wilson were honored with Nobel prizes. 

Arno Penzias and Robert Wilson with their telescope

In 2001, Wilkinson Microwave Anisotropy Probe(WMAP). This telescope was a small form of the telescope created by Penzias and Wilson. With the help of this telescope, a map was created of the afterglow and we got the following picture:

This is a detailed map of the cosmic microwave background. It took about 9 years for creating this map. Well, you will be amazed to know that this is the photo of our universe when it was born. This was how the Big Bang Theory was born and how we got the proof.

Now, the final question is, how do we know that Big Bang occurred 13.7 billion tears ago? Well, it is simple, by measuring the speed of spreading of the universe with some calculations astronomers found this time. Well, most people accept this theory because all the proof that we have got is fitting according to this theory.

 

     ~Thank you for Reading~