September 18, 2023

Joshua Morgan

11th Grade

Fountain Valley High School

The Birth of the Universe

How did our universe, something so massive and complex, come to be? What was the trigger that created the cosmos? Questions regarding the origins of our universe are so direct yet at the same time very complicated. The subject has been controversial and puzzling for ages, where many individuals have speculated and hypothesized. As of the 1960s, however, the cosmology community has come to accept only one theory: the Big Bang theory. 

The History of the Big Bang Theory

Proving a theory concerning the origins of the cosmos is quite a challenging task, one that Edwin Hubble was nonetheless able to achieve. Before the discovery of its origins, it was widely believed that the universe was stable and static. In 1924, Hubble studied the distance of objects in the sky from Earth and investigated the light that stars emitted (which can be observed on a spectrum). The astronomer noticed that the light emitted from every object he studied had one thing in common: the lights shifted to the red side of the spectrum, meaning the wavelengths got longer in proportion to their distance from the Milky Way. This indicated that the bodies of mass observed were swiftly and rapidly moving away from the Earth. From this newfound discovery, Hubble deduced that the universe was constantly expanding. This discovery also implies there was once a time during which everything in the universe was closer together with an enormous density. Thus, the Big Bang theory suggests that the origins of the universe began with a “bang” and, to this day, this expansion continues. With Hubble’s concrete evidence, the red shift and the Big Bang theory support each other. 

The Bing Bang theory, though a new and radical idea at the time, never stood unopposed; other alternative cosmological theories eventually arose to challenge the origins of the universe suggested by the Big Bang theory. For example, published by Hermann Bondi, Thomas Gold, and Fred Hoyle in 1948, the “Steady State” theory accounted for the observed expansion without suggesting a beginning in time like the Big Bang theory. It suggested that matter is continually being created to form new galaxies so that the universe maintains the same density regardless of its expansion. These two theories rivaled each other for years and neither had strong enough observational evidence to position one theory over the other. As radio astronomy was slowly emerging as a means of astronomical study, many of these theories remained purely theoretical during this time. 

What is the Big Bang Theory? 

Society has come to believe that, roughly 13.8 billion years ago, a minuscule yet incredibly hot point of infinite density and gravity was stimulated. With this trigger, all past and current matter, energy, space, and time were born – creating the universe. The singularity began to expand, initially inflating the size of the universe at a speed faster than light. According to physicist Alan Gluth, despite this being a process of tremendous change and creation, this period of expansion lasted for only 10-32 seconds. 

In the initial hot and dense environment, bits of energy formed into gluons, which produced quarks. As time passed by and the universe began to cool down, these quarks formed protons, neutrons, and electrons: the fundamental building blocks that make up everything in the universe today. This entire process occurred within one second and during this time the universe was opaque due to the free electrons scattering photons, particles that emit radiation, or light. Then, as the universe became cool enough, the negatively charged particles began to collide with nuclei to form either neutral or charged atoms. This caused the universe to become transparent and enabled light to finally shine through it, known as the “afterglow” of the Big Bang, or cosmic background radiation. Atoms soon led to molecules, and gravity drawing the matter together led to the creation of stars, planets, and galaxies. Even after the initial rapid expansion of the Big Bang, the vast universe continues to expand to this day. Scientists wonder if the universe will expand forever or someday collapse in the “Big Crunch.” 

Acceptance of the Big Bang Theory 

After the Big Bang, the universe consisted of extremely high temperatures which caused most of the contents of the universe to form intense light (radiation) instead of matter. This period was known as the radiation era. As space began to expand, this light had to fill an increasing volume of space, thus the wavelengths of light became longer and lowered their energy. Although greatly reduced in intensity, it is theorized that this radiation of the Big Bang still lingers in the universe today at a corresponding temperature of 10 K. Radiant energy at that temperature exists as microwaves. The evidence of these residual microwaves from the Big Bang, found by two unsuspecting teams of physicists, ultimately resulted in the larger acceptance of the Big Bang theory among astronomers.

In 1964, while investigating the microwave emissions from the Milky Way, Arno A. Penzias and Robert W. Wilson came across persisting background static in the detector connected to their antenna. Simultaneously, a physicist, Robert H. Dickie, and his colleagues concluded that lingering residual radiation from the Big Bang was still present in the universe with a temperature of 10K. Thus, he proposed that the radiation should be observable in the microwave section of the electromagnetic spectrum. Hearing about the persistent microwave background noise of Penzias and Wilson, Dickie’s team along with the former were able to distinguish the first observational piece of evidence to support the Big Bang Theory. They shared a Nobel Peace Prize for Physics in 1978 and their discovery of cosmic microwave background radiation led to the acceptance of the Big Bang theory within the scientific community worldwide.