Dethroned by Discovery
Rediscovering human purpose in a Copernican universe
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Ever since the earliest humans walked this Earth, they looked up to the heavens and wondered. Where are we? Why are we here? What is our purpose? In this search for meaning, science has lit the way, gradually filling cavities with knowledge and steadily pushing myth and superstition to the fringes. Over the last five centuries, these discoveries have dramatically changed our perceived place in the universe. They pushed us from the center of everything to just beings on another planet, floating in the void. On their face, these discoveries would appear to diminish our importance, but this is only half the story. While science has displaced us from the geometric center of everything, it has also elevated human consciousness closer to a place of central, if metaphorical, significance.
Our Place In the Universe
Our naked eyes can only collect enough photons of light to view a tiny sliver of the universe around us. From our perspective here on Earth, the heavens appear to rotate around us; we lie at the center, the only conscious beings in a vast universe, a recipe for certain hubris. Historically, our conception of the heavens was rooted more in myth and philosophy than in science. Aristotle thought the heavens were perfectly ordered, with the Earth at the center. The Sun and Moon were perfect spheres, orbiting Earth in perfect circles at a constant, unchanging speed. The stars were the white light of the heavens peeking through a dark mask beyond which no material substance could exist. In this perfect universe, however, a problem vexed people for millennia: the planets.
Literally meaning “wanderer,” the position of the planets, unlike the stars, could not be predicted. They often appeared to move forward and backward in the night sky. Aristotle’s model had a fatal flaw. Centuries after Aristotle, Ptolemy suggested that the planets had two orbits: the deferent, rotating around the Earth, and the epicycle, where the planet rotated within the deferent. From our perspective, this would cause a planet to move backward and forward in the night sky at various times. His explanation, however, could not accurately explain the planets’ movements either. For an ordered, predictable universe, this was a problem, but one that was mostly hand-waved away. We still believed that humanity stood at the center of it all, a narcissistic ode to understandable ignorance.
In the 1500s, Nicolaus Copernicus was among the first to challenge Aristotle and Ptolemy. He suggested that if one placed the Sun, not the Earth, at the center of the solar system, the odd movement of the planets in the sky could be explained without the need for complex orbits-within-orbits. Earth’s demotion also opened up the possibility that the Sun was one star among many. In 1600, Giordano Bruno was executed for arguing that the universe was infinitely large with many stars, each with their own worlds. Copernican heliocentricity was a parsimonious proposition, but one that still could not accurately explain planetary movement and lacked experimental proof. In the 1600s, Johannes Kepler refined the “Heliocentric” universe and further challenged Aristotle, suggesting that the planets didn’t orbit the Sun in perfect circles, but rather in ellipses. To intellectuals at the time, it must have felt like “cheating,” but by accepting imperfection, Kepler was able to predict planetary movements fairly well. Alas, he also lacked any means of proving his hypothesis.
Around the same time, Galileo Galilei pointed a telescope at the night sky and saw things no human had seen before. Galileo saw mountains on the Moon and spots on the Sun…objective evidence that the heavens did not conform to Aristotelian perfection. He witnessed the phases of Venus, something predicted by Copernicus, and saw moons orbiting Jupiter. Suddenly, Earth was not necessarily the center of anything. Galileo’s evidence, although irrefutable, drew the wrath of the church as it contradicted over a millennium of Christian teachings, and he spent his final years under house arrest. It’s easy to understand why this truth was uncomfortable; a Heliocentric solar system meant that Earth was just another planet. Why would God govern anything other than the center of the universe?
Regardless, the truth could not be ignored for long. A century later, in the 1700s, standing upon the shoulders of Galileo and Kepler, Sir Issac Newton codified the laws of gravity and motion into mathematics. The same force that brought apples to the ground when they fell from a tree, he realized, also holds the planets around the Sun. And as for the Sun, 19th-century spectroscopy comparing the Sun with the stars confirmed similar chemical composition and temperatures; the Sun was just another star, and an unremarkable one at that. While we were no longer the center of the universe, at least humanity could understand the laws that governed that universe. Or so we thought.
The Missing Planet
By Newton’s time, it was known that the planets orbit in ellipses and that the orbits themselves also rotate around the Sun, in what we call “precession.” Newtonian physics accounted for precession and accurately predicted the movement of the planets, save for one: Mercury, which appeared to get tugged off course. It was thought that there must be another planet near Mercury with gravity disrupting the predicted orbital path. We even gave this mystery planet a name: Vulcan. Yet, observations with increasingly powerful telescopes in the 19th century could not find this mysterious missing planet. Vulcan didn’t exist; it was merely another myth created to explain what we didn’t yet understand. Mercury’s orbit was not distorted by another planet, but rather by space itself.
In 1915, a patent clerk named Albert Einstein published the Theory of General Relativity, suggesting that mass warps space. For planets that are distant from the Sun, such distortions were imperceptible. For Mercury, however, the closest planet to the Sun, the impact was substantial enough to noticeably alter its orbit and render Newtonian physics inaccurate. Einstein’s theory was not proven until 1919 when astronomers traveled to Brazil for a rare solar eclipse. To test the theory, they photographed a star cluster near the Sun at the very moment the Moon blocked its light. The images of the star cluster taken during the eclipse were then compared with images of the same cluster taken on a normal night, absent the Sun’s gravitational influence. Indeed, the apparent position of the stars was slightly distorted during the eclipse, proving Einstein correct; the Sun’s mass literally bends the space around it, altering the path of light waves as they coursed toward Earth.
An Expanding Universe
Throughout all of this discovery, however, we still assumed that we were something of a rarity in the universe. We still believed we were living around the only star that harbored planets, residing in the only galaxy in the cosmos, the Milky Way. But not long after Einstein was vindicated, Edwin Hubble trained a telescope at Andromeda, which was thought to be a dusty galactic nebula. Using a new method to measure the distance to Cepheid variable stars, he came to an astounding discovery: Andromeda was 900,000 light-years away, far more distant than the most distant stars in our galaxy. Andromeda was a galaxy of its own. The paradigm was once again shattered. Today, we know the Milky Way, our galaxy, to be one of countless billions of galaxies.
Hubble went further, discovering that not only was the universe larger than previously believed, but it was also expanding. Hubble drew on data from Vesto Slipher, who had earlier noted that many distant nebulae showed a “Red Shift.” “Red shift” is a phenomenon where light wavelengths stretch toward the longer wavelengths (more red) as the object emitting the light moves away from us at high speed. Hubble showed that the recessional velocity of galaxies is proportional to their distance; Galaxies twice as far away recede twice as fast. This relationship, now called Hubble’s Law, suggests that galaxies are not exploding away from us in a static space (which would put us at a special center), but that space itself is expanding, carrying galaxies along like dots on an inflating balloon. The farther apart two points are, the faster the space between them stretches.
With these observations, the idea of an eternal, static universe was forever put to rest. An expanding universe also meant that, if we were to run the clock backward, the universe would become smaller until it reached a singular point, or singularity. This expansion must have been kicked off by a dramatic event, which we call the Big Bang. This origin story, of course, was theoretical. Confirmation would come a few decades later when physicists using a horn antenna at Bell Labs noticed a persistent “hiss” or buzzing noise coming from all directions in the microwave range. Months of searching did not reveal the signal’s source (even pigeon droppings were considered). Until, that is, they happened across research that predicted that the Big Bang would produce exactly this kind of radiation.
According to the Big Bang model, the universe would be extremely hot and dense in its first moments. As it expanded and cooled, the light (photons) from that hot phase would be stretched into longer wavelengths, eventually into microwave frequencies. This unexplained “hiss” was the “afterglow” of the Big Bang; observational evidence of the universe’s first moments. Still, the Big Bang Theory had some problems. That cosmic microwave radiation was too uniform. In the 1980s, a modification of the Big Bang theory added a prelude, known as cosmic inflation: an extremely brief but explosive period of exponential expansion in the universe’s first moments. It explains how the universe rapidly grew from a tiny singularity smaller than a proton by stretching space itself faster than the speed of light, smoothing out initial irregularities. When inflation ended, energy converted into a hot, dense soup of particles and radiation, marking the beginning of the Big Bang. The cosmic inflation theory is generally accepted today.
Since the 1990s, new, more powerful telescopes and observational methods have also proved that our Sun is alone in harboring planets, with new worlds being discovered almost weekly. While we still know very little about these distant worlds, one thing is clear: they represent trillions of potential opportunities for life to emerge. Alas, our special place in the universe, it would seem, isn’t all that special after all. In the course of five short centuries, we have been dethroned by discovery. This “Copernican Principle” tells us that we occupy no special place; we are not privileged observers of the universe. As we will see, however, that while these discoveries pushed us to the edges of the map, they elevate the importance of humans as conscious beings in a universe that is discovering itself.
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Bits of Being (coming soon)
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