The study of the physical universe in its entirety, viewed through the lenses of astronomy and physics, is called cosmology. This scientific discipline grapples with understanding the nature of everything, its origin and the rules that govern universal relationships. Expressions of curiosity about the stars filling the nighttime sky are found as early as recorded history itself. Man, it seems, possesses a sense of awe and wonder about where it all came from and how it works. Over time, one cosmology revolution after another has brought ever more sophisticated ways of grasping its elements.
Taking up the evolution of cosmological ideas in the 16th century, there followed three major shifts in the predominant theories regarding the universe. Up until this time, many religious and philosophical beliefs held to a view based on a flat, circular earth, suspended in water around which the rest of the universe revolved. The subsequent 5 centuries were witness to progress toward a more rational and empirical understanding than had occurred up to that point. Parallel developments of the scientific tools that enabled observations made significant contributions to this pace of exploration and discovery. A huge shift took place when Nicolaus Copernicus published his work.
The Sun Becomes the Center
Copernicus made several astronomical observations leading him to conclude that the sun rather than the earth was the center of the solar system. This hypothesis was published in 1543, the year of Copernicus’ death, and had a mixed reception. Later Galileo Galilei took up this work using the telescope to further expound upon the heliocentric idea. Galileo was persecuted by the religious establishment that viewed this theory as heretical.
The Explanation of Gravity
Sir Isaac Newton caused another substantial shift in the understanding of how astronomical bodies interact. Publishing his now-famous laws of motion and universal gravitation in 1687, he advanced the body of scientific knowledge dramatically. This work accurately described and predicted the motions and relationships among stars, planets and other celestial bodies. His work stood as the predominant framework of scientific thought about cosmology until the dawn of the 20th century.
The Modern View of the Universe
In 1905, Albert Einstein published a paper proposing general relativity. His work was instrumental in advancing the understanding of time and space and their relationship. The observations and mathematics Einstein presented established an absolute speed of light in a vacuum. Further, they enabled a more precise scientific understanding of how gravity works and its connection to the mass of objects such as planets and stars.
The progress in human understanding of the universe, its origins and dimensions continue today. Very sophisticated scientific instruments like the Large Hadron Collider and advanced research are shaping the next shift of cosmological theories and ideas. Undoubtedly, more changes lie ahead as answers to the questions raised centuries ago are discovered.