The Universe: An Unraveling Mystery

Rolando J. Casado Ladrón

Since before I can remember, I have always been fascinated by the celestial bodies over my head. Later I spent hours looking through a telescope identifying every constellation I could find at night. During high school I finally started to understand the complicated mechanics the universe endured. I was even more amazed when I saw that the same Physical Laws that applied to me ruled over the entire Universe as well. And the more I learned the more questions I formulated. What was the universe? What is it made off? Did it begin or was it always there? If we had a beginning, then there would surely be an end. Then I came across a peculiar theory that explained some of my most burning questions. This theory is called the Big Bang. 

This theory explains one possibility of how the Universe came to be the way that it is now. The Hubble Law is one of the few pieces of physical evidence that supports the Big Bang. It dictates that the universe is ever expanding and the galaxies are getting farther apart at a velocity proportional to the distance between them, this relationship is known as the velocity-distance relation. The idea is that if the Universe is expanding now then that means that at some point it was smaller, unimaginable small. Going back billions of years this theory presents the Universe in the beginning as a small, dense and hot sphere. Then the story goes that the sphere “exploded” giving birth to the Universe we know today. 

From this point on gravity becomes the most influential part in the formation of the Universe. During the first second after the blast there were a handful of elements which Helium was the dominant. During this gaseous phase gravity starts to combine the gas particles forming new elements. Then the gas became clusters and started gaining mass until a few minutes later galaxies, solar systems and planets were formed. I can’t believe that a basic force as gravity is so influential in the Universe. Then I asked myself if gravity is a constant force that repels and attracts bodies with mass then, in the beginning, the particles should have stayed in a perfect grid. So what was the trigger for the difference in mass within the particles? The answer came from Einstein’s equations of relativity were he mathematically explained the expansion of the Universe and proved the existence of dark energy. It is represented in the equation as the cosmological constant. This type of energy is the cause for the accelerated expansion of the universe and forms about 70 % of the total density of energy in the Universe. This is the story of how the Universe came to be as we know it today. These equations also predict that the Universe is getting colder and farther apart until one day it will lose all of its energy. What happens after this happens? Will it stay there motionless or might there be another bang?

This theory has been able to explain to me how the Universe came to be but opened new ones. What caused this incredible dense and small “particle” to explode”? What surrounded this “particle”? If time and space came after the bang then how can we define or describe this particle? Reading and learning about the Universe is my passion and realizing that the laws of Physics are the explanation of how the Universe works has attracted me to the physics area of study. The Universe is a mysterious place and learning about it attract my attention and it is why my dream is to work at NASA.