WHAT IS THE BIG BANG THEORY? - SCIENCE - 2025

The Big Bang theory, or the big bang, consists of a scientific model that explains the emergence of the universe through astronomical observations.

The Big Bang is believed to have happened 15 billion years ago. It was a great cosmic explosion that produced enough matter for the creation of planets, stars, and galaxies.

This theory states that the universe was compressed into a primitive atom, that it contained an incredible amount of highly concentrated matter, and that it was also extremely radioactive.

Radioactivity produced the great explosion and started the expansion of the universe. Later the matter began to condense and galaxy clusters appeared.

The elements that were scattered due to the explosion are mainly made up of particles such as positrons, neutrinos, photons, baryons, mesons and electrons. Currently more than 89 atoms are known.

The Big Bang is the most accurate theory about the creation of the universe, but it should be noted that there are still unanswered questions.

For example, there are questions about the end of the expansion cycle and the possibility that the universe will contract again.

Another big conundrum is whether the universe is open or closed due to dark matter - this is a key question for science.

The first theories of the creation of the universe

One set of theories explains that the universe was created with a great cosmic explosion, while others claim that this universe always was and remains in a state of continuous creation. This last theory was discarded.

The Big Bang theory is based on scientific hypotheses; These include Einstein's theory of relativity and other research works on principal particles.

In 1922 the cosmologist Alexander Friedmann was the first scientist to formally explain the procedure of an expanding universe, through the equations of relativity.

It also highlights the contribution of scientist Edwin Hubble, who observed through a telescope and noticed that the stars were constantly moving away from planet Earth at high speed.

In 1927 the Belgian Catholic priest and astronomer George Lamaître was the creator of what would be called the Big Bang theory, since he was able to demonstrate it through the calculations of Hubble's law, Einstein's theory and Friedmann's equations.

George Lamaître proved that there was a large explosion at a specific point in the universe and generated a hypothesis according to which the universe was compressed to a small point due to hot radiation, and that it subsequently froze.

According to Lamaître, the intensity of the explosion was not great enough for the universe to continue its expansion indefinitely. Therefore, it was the force of the initial explosion that initially determined the galaxies to separate from each other.

Over time, this force lost its intensity. The galaxies had condensed to such an extent that most of the matter in the universe was already concentrated in them.

From that moment the cosmic repulsion began to act, causing the galaxies to continue to separate, as they are currently observed.

American astrophysicist George Gamow has also used the Big Bang theory to explain the origin of the universe in a simpler way than Lamaître's.

Gamow argued that the temperature of the explosion became so high and the force of the explosion so great, that this was enough for the universe to expand indefinitely.

The Big Bang Theory and the Steady State Theory

In 1949 the astrophysicist Fred Hoyle was one of the greatest enemies of Lamaître's theory.

Hoyle was one of the scientific defenders of the theory of the steady state, since it seemed ridiculous to him that the creation of the universe occurred by an explosion.

During a radio show, Fred Hoyle sneered at the theory as a "Big Bang," and due to the controversy that the term generated, it eventually became the formal title.

The steady-state theory explains that the formation of hydrogen atoms has been constant over time, which means that galaxies have been constantly condensing.

This indicates that the universe will always be expanding, and that it has never had a beginning nor will it have an end.

Some astronomers disagree with the idea that the universe can remain in a steady state and that hydrogen atoms are constantly being produced.

Both the Big Bang theory and the steady state theory assume that the universe was produced from a certain primitive atom.

At present, through technological advancement and mathematical knowledge, both theories could be clarified, providing details of how galaxies began their existence, how they have continued until now, and how the universe originated.

Astronomers of the future will be able to clarify a series of unknowns, but currently the Big Bang theory is considered the best hypothesis of the beginning and evolution of the cosmos.

Discovery of the Big Bang echo

In 1965 physicists Arno Penzias and Robert Wilson discovered cosmic microwave background radiation by chance, and this discovery ruled out the steady state theory.

This happened when they were working on creating the first communications satellite to establish connections with areas very distant from others.

They placed a mini metal ball-shaped satellite in space orbit, which sent frequencies to a trumpet-shaped antenna located in New Jersey.

This experiment was carried out with the intention of fulfilling the function of a radio telescope, through which they sought to eliminate all interferences that could cause noise.

However, there was microwave interference affecting the signal and they did not know where it was coming from.

They tried by all means to eliminate the noise, until they came to the conclusion that it was due to pigeon droppings. They managed to resolve this issue but there was still the echo with the same force.

Penzias and Wilson, without having an explanation of what was happening, consulted with cosmologists James Peebles and Robert Dicke, of Princeton University.

Peebles and Dicke were developing a device that was capable of capturing the microwave emission from the Big Bang.

Penzias contacted the scientists to ask about the noise, but when Robert Dicke ended the call with Penzias he told his team, "Guys, you guys got ahead of us."

Arno Penzias and Robert Wilson received the Nobel Prize in Physics in 1978 for this discovery.

References

1. What is the Big Bang? (2016). Source: spaceplace.nasa.gov
2. The Story of Universe: Big Bang. (2016). Source: esa.int
3. Elizabeth Howell. The Big Bang Theory. (2017). Source: space.com
4. Big Bang Theory. Source: big-bang-theory.com
5. Matt Williams. Big Bang Theory: Evolution of Our Universe. (2015). Source: universetoday.com