How was the universe formed? What led to the formation of stars, planets and galaxies? These are some of the questions that have been asked by millions of people throughout history. Specifically, scientists want to seek an explanation of all the phenomena that exist. This is the origin of the Big Bang theory. For those who do not know it yet, it is the theory that explains the origin of our universe. It also includes the explanation of the existence of planets and galaxies.
If you are curious and want to know how our universe was formed, in this post we will tell you everything. Would you like to know in depth the theory of the Big Bang?
Characteristics of the Big Bang theory
It is also known as the Big Bang theory. It is the one that maintains that our universe as we know it began billions of years ago in a big explosion. All the existing matter in the universe was currently concentrated in just one point.
From the moment of the explosion, the matter began to expand and is still doing so today. Scientists do not stop repeating that the universe is constantly expanding. Therefore, the Big Bang theory includes the theory of the expanding universe. The matter stored in a single point not only began to expand, but also began to form more complex structures. We refer to the atoms and molecules that, little by little, were forming living organisms.
The date of the start of the Big Bang has been estimated by the scientist. It had its origin approximately 13,810 million years ago. During this stage in which the universe was newly created, it is called the primal universe. In it, it is assumed that the particles had enormous amount of energy.
With this explosion the first protons, neutrons and electrons were formed. The protons and neutrons were organized into nuclei of atoms. However, the electrons, given their electrical charge, organized themselves around them. In this way the matter originated.
Formation of stars and galaxies
Our solar system is located within the galaxy known as the Milky Way. All the stars we know today began to form a long time after the Big Bang.
The first stars are believed to have started forming 13,250 million years ago. Approximately 550 million years after the explosion began to appear. The oldest galaxies originated 13.2 billion years ago, which makes them also older. Our solar system, the Sun and the planets was formed 4,600 million years ago.
Evidence of an expanding universe and the explosion
To prove that the Big Bang theory makes sense, evidence must be provided that the universe is expanding. These are the evidences that there are in this respect:
- Paradox of Olbers: The darkness of the night sky.
- Hubble’s Law: It can be verified with the observation that galaxies are moving away from each other.
- Homogeneity of the distribution of matter.
- Tolman effect (variation of surface brightness).
- Distant supernovae: A temporary dilation is observed in their light curves.
After the moment of the explosion, each particle was expanding and moving away from each other. What happened here was something similar to what happens when we inflate a balloon. As more air is introduced, the air particles expand more and more until they reach the walls.
Theoretical physicists have managed to reconstruct this chronology of events from a 1/100 of a second after the Big Bang. All the material that was thrown was composed of the elementary particles that are known. Among them we find electrons, positrons, mesons, baryons, neutrinos and photons.
Some more recent calculations indicate that hydrogen and helium were primary products of the explosion. The heavier elements were formed later within the stars. As the universe expands, the residual radiation of the Big Bang continues to cool until it reaches a temperature of 3 K (-270 ° C). These vestiges of strong microwave background radiation was detected by radio astronomers in 1965. This is what the expansion of the universe shows.
One of the great doubts of scientists is to solve if the universe is going to expand indefinitely or if it will contract again. Dark matter has great importance in it.
Discoverers and other theories
The theory that the universe is expanding was formulated in 1922 by Alexander Friedmann. He was based on Albert Einstein’s theory of general relativity (1915). Later, in 1927, the Belgian priest Georges Lemaître based himself on the work of the scientists Einstein and De Sitter and reached the same conclusions as Friedmann.
Therefore, scientists do not come to another conclusion, only that the universe expands.
There are other theories about the creation of the universe that are not as important as this one. However, there are people in the world who believe and consider them true. We list them below.
- Theory of the Big Crunch: This theory bases its foundation on that the expansion of the universe is going to slow down slowly until it begins to retract. It is about the contraction of the universe. This contraction would end in a great implosion known as Big Crunch. There are not many tests that corroborate this theory.
- Oscillating universe: It is about our universe oscillating in a constant Big Bang and Big Crunch.
- Stationary state and continuous creation: It maintains that the universe is expanding and that its density remains constant because there is material in continuous creation.
- Inflationary theory: It is based on the same characteristics as the Big Bang but says that there was an initial process. The process is called inflation and the expansion of the universe is faster.
Finally, there are some people who think that the universe was created by God or some divine entity.
With this article you will know more about the formation of our universe and expansion. Do you think that one day the universe will stop expanding?