The Big Bang Theory explained by a student

Our homeworld, Earth, is the third planet in the solar system that revolves around the sun that also revolves around our galaxy, the Milky Way, which is included in a group of galaxies called the Local Group, that form part of the Virgo Supercluster, which is itself a component of Laniakea Supercluster.

Photo by NASA on Unsplash

You get the point. The universe is a pretty large place to be in and believe me or not, it is still expanding. Of course, the rate of expansion today is not comparable to what it once was in the first seconds of the universe after the “Big Bang”.

There I said it, the Big Bang. Now, you might wonder what is the Big Bang. It is a theory and the most accepted scientific explanation of what is the universe’s origin, properties, and evolution. According to the said theory, the universe began 14 billion years ago in an extremely hot and dense state called the infinitesimal singularity which then cooled and began to expand rapidly. That infinitesimal singularity is a million billion billionths the size of a single atom. Can you imagine that?

Now, this is where it gets confusing. Because of the term Big Bang, many people assumed (including me) that it is an explosion but it was not. Rather than an explosion, it is an expansion, a rapid one. The onomatopeia “bang” is always associated with guns, bombs, and explosions, thus many people are misled by this.

As per the theory, the universe, including time, space, and energy, was condensed into the aforementioned tiny singularity, which began to expand and cool. The Big Bang is the expansion of space. This means that the universe has no center since the singularity was not in a place on the planes of space or time because the singularity is the space and time itself. Isn’t that mind-boggling?

But, what really caused that singularity to expand, to begin with? Quantum fluctuations are the most known assumption that made the subsequent inflation into the universe we know of today. It is the random change in the amount of energy at a point in space that likely triggered the said inflation. But in all honesty, no one really knows what happened during the earliest time of the universe or if there was even a “bang”. We can only observe everything after the aforementioned “expansion”.

There are at least three observations that support the Big Bang theory: cosmic microwave background radiation, the abundance of light elements, and the expansion of the universe.

• Cosmic microwave background radiation is the remnant of the heat left by the Big Bang. Astronomers found microwaves, light with a significantly longer wavelength, in previously dark portions of the cosmos by using more powerful and sensitive telescopes. They determined that the microwaves were thermal radiation from the early stages of the universe’s development
• The abundance of light elements in the universe is a piece of crucial evidence that backs the Big Bang theory. The elements detected in the Universe are now understood to have been produced in one of two ways. Light elements (deuterium, helium, and lithium) were created in the initial few minutes of the Big Bang, while elements heavier than helium are assumed to have originated in the interiors of stars that formed far later in the Universe’s history.
• The universe has been expanding ever since the Big Bang. Astronomers use the doppler shift of light from stars and galaxies to determine how objects in the universe move in relation to the Earth and one another. They eventually concluded that every galaxy and other objects in the universe is traveling away from each other at roughly the same rate.

On top of this factual evidence: cosmic microwave background radiation, the abundance of light elements, and the expansion of the universe, the Big Bang theory remains to be incomplete. The theory explains what happened after the inflation yet it fails to explain what was there before the inflation or was there even inflation, to begin with.

The Big Bang theory is only a hypothesis rather than a tested theory. It is an effort to physically explain the beginning of the universe. The theory did a great job of tying the gathered data and projecting all of this motion to an origin point. But like any other theory, it has a fatal flaw, “What caused the Big Bang to happen and why didn’t it just stay on eternal singularity?”. Again, we don’t know and we won’t even know, given our current depth of understanding. But I’d rather be honest about our stupidity than makeup stories to hide it.