The big Bang theory is one of the most awesome theories of modern science. This theory answers so many questions asked by scientists and philosophers throughout the ages. This theory tells us how our universe came into existence, and how it became what we see today. Because of the big bang theory, we now know how the earth we live in, the sun and the moon and all the other stars and galaxies in the universe formed and shaped the universe as we see it.
An Infinite Universe Theory
Before the theory was proposed, scientists used to believe that the universe was infinite. They believed that the universe had no beginning, and that it was always like this. But that notion was changed after scientists in the early 1900s made a few discoveries that changed modern physics as we know them.
Albert Einstein’s Theory of General Relativity
In 1914, Albert Einstein proposed the theory of general relativity. According to that theory, either the universe was getting bigger or it was getting smaller. Scientists at that time rejected this idea because the laws of physics at that time didn’t support the theory. Even Einstein himself rejected the idea at the time.
Edward Hubble’s Observation
Then in 1929, Edward Hubble made a very interesting observation when he was studying the distant stars and galaxies. He found that the light coming from the stars was getting redder and redder. This happens when an object is moving away from us. When an object is coming towards us, the light rays it emits will get bluer and bluer, and when it moves away, it will gradually get redder and redder. So from this, Hubble realised that the stars and galaxies were gradually moving away from us. They were also moving away from each other. This meant that the universe was gradually getting bigger, just as Einstein had said.
The Beginning of the Universe As We Know It
So if the universe is increasing now, then it was surely smaller in the past. And the further back we go in time, the smaller the universe gets. And if we continue going back in time, we will eventually come to a point in time when the universe itself was very, very small. Then something happened and the universe started getting bigger and bigger. Scientists later named this phenomenon as The Big Bang.
Before The Big Bang
Before the Big bang occurred, there was no matter, no space, and even no such thing as time. It was known as the singularity. There was nothing but a small ball of energy with no space and no volume but infinite density. The ball of energy was infinitely hot, and infinitely dense. After the big bang occurred, space was created, and the volume and size of the universe started increasing i.e getting bigger. And at the same time, the temperature started to decrease, i.e. the universe started cooling down. As it cooled, matter was created in the form of subatomic particles like neutrons and protons. All this happened 13.8 billion years ago.
As time went on, the universe continued getting bigger, and it started cooling down and gradually all the stars, galaxies, and planets formed. The universe we see today is still cooling and expanding. If the universe stops expanding, there will be a Big Crunch and the whole universe will be destroyed.
That is a topic for later discussion.