Expanding the Cosmos One Discovery at a Time
Photo: Kevin Quezada @kevinqaFor every difficult question we answer, we expose more questions. Hubble expanded the borders of our universe beyond the Milky Way - could future discoveries expand the universe further still? Could our universe be one of many in a multiverse?
Every once in a while, a person emerges from the ranks of anonymity to make a lasting mark on history. Through means honest and dishonest, peaceful and aggressive, scientific and mystical, these historical celebrities enact radical change and transformation upon the world around them and in so doing, capture the hearts, minds, and imagination of future generations.
Edwin Hubble was such a person. Though he made many important discoveries during his career, there is one in particular that forced us to radically expand our model of the cosmos in a mind-blowing way.
Allow me to set the stage.
The year is 1922. The place is Mount Wilson, California, site of the Hooker Telescope, the world's most powerful device of its kind at the time. At the helm of this device sits Edwin Powell Hubble, a 33 year-old astronomer only five years removed from college. Edwin wanted to be an astronomer from the time he was a boy, but, being a dutiful son, he fulfilled his father’s wishes and studied law instead. He was at Oxford University doing just that when he received word that his father had passed away. Upon returning home to take care of his mother, Edwin, then 25, decided to abandon law and pursue his dream. He received his PhD in 1917 after publishing his dissertation, “Photographic Investigation of Faint Nebulae,” and became a professional astronomer.
In order to fully appreciate Hubble’s discovery we must first discuss the model of the universe as people knew it back then. You see in Hubble’s day, astronomers believed that the Milky Way galaxy was a so-called "island universe” - an island of matter and energy surrounded by the infinite void of space. In other words, our model of the cosmos back then was comprised of the Milky Way and nothing else. The Milky Way was the entire universe - or so we thought.
With their pre-Hooker telescopes, astronomers observed two different types of celestial bodies in the Milky Way: stars and faint, imprecise shapes which they called nebulae. No one knew exactly what nebulae were. The prevailing theory was that they were oddly-shaped clouds of gas or diffuse stars. Astronomers named them according to shape - the Spiral Nebula, the Eagle Nebula, and so on. The important thing to note here is that it was presumed that both stars and nebulae were located within the confines of the Milky Way galaxy.
With the state-of-the-art Hooker telescope at his disposal, Edwin got an unprecedented view of the heavens. And as you probably guessed from the title of his dissertation, nebulae were of particular interest to him. However, what he discovered about them was beyond anything he could’ve imagined. Thanks to this powerful new telescope, Hubble was able to make calculations about the nebulae’s precise whereabouts and the results must have surely blown his mind. According to Hubble’s calculations, the nebulae were thousands and in some cases millions of light-years away. Based on these findings, nebulae simply could not be located within the Milky Way.
But where else? If the Milky Way constituted the entire universe, how could nebulae exist beyond its borders? Imagine Hubble's reaction as it dawned on him. Imagine the wonder and awe he must’ve felt when he realized that nebulae were not clouds of gas or diffuse stars as had been previously thought but rather entire galaxies unto themselves, like the Milky Way, only millions of light years removed, scattered across the heavens, and too numerous to count.
Put yourself in his shoes for a moment. In a flash of insight and moment of discovery, Edwin Hubble’s universe suddenly expanded from the size of the Milky Way to the size of billions of Milky Ways separated by immense distances. It’s no surprise that Hubble’s radical new theory was initially met with scorn and dismissed out of hand. Even today, people have difficulty wrapping their heads around the vastness of the universe. If our puny minds can barely handle the sheer breadth of the universe now, imagine how people in the 1920’s felt! However, Hubble’s observations and accompanying equations were undeniable, and soon his peers capitulated, accepting as fact what we all take for granted today.
Our understanding of the universe has come a long way. We started out on a flat-earth located at the center of all creation, then progressed to a round earth. A while later Copernicus had the nerve to propose that the sun—not the earth—was at the center of the universe. Finally, we believed that the Milky Way formed the entire universe. Now we know that our galaxy is just a grain of sand on the cosmic beach. Whenever we think we have a handle on things, someone like Edwin Hubble comes along and blows our understanding out of the water. For every difficult question we answer, we expose more questions. Hubble expanded the borders of our universe beyond the Milky Way - could future discoveries expand the universe further still? Could our universe be one of many in a multiverse?
If we learn anything from Hubble and all the other historical celebrities who disrupted the prevailing models and theories of their time, it’s that we don’t know much of anything. And what we do know is subject to change drastically and with little warning. We may never fully understand the nature of the universe, reality, human consciousness, and so on. All we can ever hope for, to paraphrase Carl Sagan, is an ever-improving understanding, not a perfect one. Edwin Hubble’s contributions helped improve our understanding of the universe in a major way, and for that we should be grateful.
Thanks Ed!
