The Discovery of the Big Bang: Understanding the Origins of the Universe

The Big Bang theory is the prevailing cosmological model for the early development of the universe. It states that at some point in time in the past, all matter was concentrated in a single point from which an immense explosion occurred that spread out the matter, spawning stars, galaxies, and planets. The Big Bang Theory is one of the cornerstones of modern cosmology and its discovery has given us insight into the origin and evolution of the universe.

I. Early Ideas About the Universe

Throughout the centuries, humans have wondered about the origin of the universe and how it works. Before the Big Bang theory was proposed, the prevailing belief was that the universe had been eternal and unchanging. This is known as the Steady State Theory, which was first proposed by German physicists Friedrich Wilhelm Bessel, Bernhard Schmidt, and David Friedmann in 1924.

A few decades later in 1929, Edwin Hubble’s observations showed that the universe was actually expanding, thus contradicting the Steady State Theory. This finding marked a significant departure from the long-standing belief that the universe was static and unchanging.

II. Georges Lemaître and the Expanding Universe Theory

Belgian physicist Georges Lemaître was the first to propose a theory based on this idea of an expanding universe. In 1931 he proposed his Expanding Universe Theory in which he hypothesized that the universe was initially concentrated in a single point, which he called the “Primeval Atom”. This Atom began to expand and spread out due to the force of gravity, spawning stars, galaxies, and planets.

At the time, Lemaître’s theory was met with skepticism by the scientific community, as it contradicted the prevailing belief of a static universe. He further developed his theory by proposing the use of a mathematical equation known as the Friedmann-Lemaitre-Robertson-Walker metric which described this cosmic expansion.

III. Edward Hubble and the Foundation of the Big Bang Theory

In the 1940s, American astronomer Edwin Hubble used the technology of the Hale Telescope to observe distant galaxies and noticed that the universe was expanding. The observation of this cosmic expansion was one of the major pieces of evidence for the Big Bang theory. Hubble also proposed a new mathematical equation known as the Hubble’s Law, which described the relationship between the expansion rate of the universe and its distance from Earth.

This equation helped astronomers make significant progress in calculating the age, mass, and size of the universe. By combining his observations with Lemaître’s mathematical equations, Hubble was able to build the scientific basis for the Big Bang theory.

IV. The Big Bang Theory

The Big Bang Theory is the prevailing cosmological model that describes the creation of the universe. According to the theory, the universe was initially concentrated in a single point known as the primeval atom, or the singularity. This singularity then underwent an immense, explosive expansion known as the Big Bang.

During this expansion, the primeval atom began to stretch, creating the fabric of space-time and filling it with particles, creating the matter that eventually formed the present day universe. The expansion initially increased quickly due to the force of gravity and gradually slowed down as the universe cooled and matter spread out more evenly.

V. The Cosmic Microwave Background Radiation

In 1964, radio astronomers Arno Penzias and Robert Wilson discovered a low level noise coming from all directions that was uniform. This noise was later identified as the Cosmic Microwave Background Radiation (CMB) which was a remnant of the Big Bang.

The discovery of this cosmic radiation was the final and most important piece of evidence that confirmed the Big Bang Theory and consolidated it as the prevailing cosmological model. The CMB corresponded to a temperature of -273.15° Celsius and was found to be equally distributed across all directions of the universe.

VI. Refining the Big Bang Theory

Since its discovery, modern cosmology has focused on understanding and refining the Big Bang Theory. Over the years, new evidence has been found to corroborate the theory and new theories have been proposed to explain the pre-Big Bang epoch and the evolution of the universe that followed.

Currently, cosmologists are focused on understanding the composition of the universe and its accelerating expansion. They are also trying to explain phenomena such as dark matter and dark energy which play an important role in universe evolution, but remain mysterious.

The discovery of the Big Bang and the development of the Big Bang Theory has enabled us to understand the origins of the universe and gain insight into its evolution. What began as a hypothesis proposed by Georges Lemaître and embraced by Edwin Hubble has become the cornerstone of modern cosmology. It has propelled the field of astronomy and cosmology into a new era and opened up new avenues of exploration.