It all started veeery long ago. So long ago that none of the fairy tales beginning with the words “a long time ago …” can describe this story. Back then, there was no one who could write, tell, or listen to this fairy tale.
There were no “seven rivers” and no “seven mountains” for a new story to happen. There were no forests or rivers. There was no Earth. There was no sky or air. There was no Sun, no Moon, no single planet, and no star. Moreover — there was no space or time.
All of this happened about 13.7 billion human years ago. Was there time then, was there anything? If so, WHAT was it? A very good question!
The Big Bang and the beginning of everything
How do we know that about 13.7 billion human years ago something really important happened? Here is the story, which for me is a reason for extraordinary amazement over the nature of our Universe and Life.
Over 200 years ago, one of the most influential philosophers of all time, Immanuel Kant, wrote:
“Two things fill the mind with ever new and increasing admiration and reverence as we reflect on it more often and persistently: the starry sky above me and the moral law within me.”
Attempts to understand the origin and the nature of the Universe have happened in almost all religions throughout the history of mankind. On the other hand, every scientist dreams of discoveries that will shake the current paradigm of knowledge. For such a discovery, after all, you may get the Nobel Prize, right? So, must science and faith be opposing worlds?
At the beginning of the twentieth century, scientists were convinced that the Universe has neither a beginning nor an end. It did not answer the question of how is it possible that the Universe does not collapse on itself as a result of indisputable gravity.
Discoveries by Edwin Hubble
In 1929, Edwin Hubble made a series of famous observations. Using the Dopler effect — the same one that allows policemen to measure the speed of a car — Hubble found that the light of the galaxies clearly shows that they are moving away from Earth, no matter which direction we measure.
The further the galaxy is located, the faster it moves away from us. So if everything in the Universe is moving away from each other, then after reversing the time arrow we would have to come across a moment in which all the galaxies were at one point, an unimaginably condensed cluster of matter.
But would it be the matter as we commonly understand it?
Background radiation - the discoveries of Penzias and Wilson
In 1965, Arno Penzias and Robert Wilson discovered the so-called background radiation. While observing the sky with a new frequency detector, they found something that seemed the interference noise.
After ruling out all possible sources of noise (including a pair of pigeons that nested in a horn antenna), Penzias and Wilson realized that this noise came from space and was blackbody radiation of only 2.7 K (only 2.7 greater than absolute zero).
The existence of radiation coming from an object with such a low temperature, importantly, coming from all possible directions, could only be explained using the Big Bang theory: an explosion that resulted in the expansion and cooling of the Universe in an unimaginable short time.
Another convincing proof of the correctness of the Big Bang theory is the distribution of elements in the Universe, especially hydrogen, deuterium (a form of hydrogen), and helium. The deuterium content is amazingly constant in both the stars that are close to us and distant galaxies. This confirms the hypothesis that all deuterium present in the Universe was formed at incredibly high temperatures immediately after the Big Bang.
Is our universe expanding or shrinking?
After the victory of the Big Bang theory, it could seem that the fate of the universe depended on its density: the light Universe should expand into infinity, and the heavy Universe, due to the action of gravi