Illustrations by Aimee Chang
It could have been earwax. It turns out that the texture of a person’s earwax is not determined by environment but rather is written into a person’s genetic code. Some of us have hard, dry earwax, some of us have goopy earwax, and some of us have a combination. Thus, 500 years ago when it seemed useful to Europeans to start organizing people by skin color, they could have gone by earwax instead. Had they, for some reason or another, been fascinated by earwax, chattel slavery might have been organized around whoever had the earwax that was deemed less valuable. Race might have been defined by our ear excretions.
Hundreds of years after the advent of chattel slavery, it’s easy to see why race is defined by skin color. Skin color offers a highly visible cue that makes sorting easy—at least until rape proliferates. The variation in human skin tones is due to a pigment called melanin, which comes from the Greek word melas, “black, dark.” Melanin is found in most living creatures, and when it is studied scientifically, researchers usually use the ink of Sepia officinalis, the common cuttlefish. Our social sorting by skin color can be put in more technical terms as a question of how much melanin our bodies produce and maintain as part of our epidermic structure.
Of course, in 2016, melanin content is not the only reason for one’s identification or racialization as Black. Today, Blackness is recognized as a cultural identity that is entangled with a historicity rooted in melanin content but not limited to it. In one study, the same picture of a woman with dark skin was racialized differently when her skin was lightened, and especially when her nose was made smaller. Studies show that phenotypic stereotypes about nose shape, hair texture, and hair melanin content function as cues in tandem with skin melanin. Meanwhile, what we have learned from studying dna and biochemistry tells us that sorting people by skin color is arbitrary for many scientific purposes, and that race is more about how we organize ourselves than about any absolute scientific truth. As the Africadian George Elliott Clarke, Canada’s parliamentary poet laureate, tells it, “Black is maple brass coffee iron mahogany copper cocoa bronze ebony chocolate.” Black identity is a sociogeographic construct with a real but tenuous connection to science.
Technically, melanin is a set of biomolecules that we think are synthesized by enzymes and that are notably very visibly colored. There are three types of melanin: the most common, eumelanin, which appears black or brown and occurs in skin and hair; the less abundant pheomelanin, which is on the yellow-to-red spectrum; and neuromelanin, which appears in high concentrations in the human brain, but the function of which we essentially don’t understand at all. For the most part, it seems, we don’t understand melanin.
Despite this lack of scientific understanding, the social consequences of melanin are understood intimately by many of us. Those of us who have more of this eumelanin in our skin are more likely to die at the hands of police. One’s comprehension of this social reality probably depends on the ways one resembles Terence Crutcher, bleeding out on the side of the road, or Aiyana Stanley-Jones, bleeding out on the living room couch. For centuries, scientists who had low eumelanin content in their skin interpreted high content to scientifically equate to a lower intellect. Ironically, neuromelanin is abundant only in animals with what humans would call “high intelligence.”
This is perhaps not surprising when we consider that contemporary theories of the history and philosophy of science teach us that science and society coconstruct one another, and there is perhaps never a more salient site for this lesson than on skin with high melanin content. Indeed, it was a supposedly enlightened Europe that enshrined the animus toward darker-skinned people in its colonial satellites as a tool to help maintain a unidirectional flow of resources, from the colonies to the heart of empire. Rather than skeptically considering the substance of these colonial sensibilities, scientists largely sought to substantiate them through a search for their scientific foundations. Science thus became a process in which bias was consecrated by scientists. Racism was axiomatic, rather than a belief requiring skeptical investigation.
Today, many of us would agree there is no scientific basis for the animus toward eumelanin-abundant people, only economic convenience. The timeline is consistent with this perspective, since race was invented hundreds of years before the 19th-century discovery of melanocytes—the cells that produce the pigment we call melanin. Before that, racial construct was a chaotic mix of hatred, cruelty, greed, and perversity. In a classic example of the illogical nature of racial construction, we have Thomas Jefferson, who owned his Black mistress (or what many of us today would call “sex slave”) Sally Hemings and their children, waxing on about whiteness: “Are not the fine mixtures of red and white, the expressions of every passion by greater or less suffusions of color in the one [whites], preferable to that eternal monotony, which reigns in the countenances, that immovable veil of black, which covers all the emotions of the other race?” In other words, the still highly esteemed founding father of the United States preferred the expressive faces of free white people to the stoic faces of enslaved Black people, and he believed these apparent differences were due to race, not relative states of freedom and captivity.
There is no science underpinning Jefferson’s feelings, only prejudice—not terribly different from when singer John Mayer announced, “My dick is sort of like a white supremacist.” At least Mayer had the audacity to tell the truth about his preference. But a curious feature of enlightened Europe was the obsession not just with conquering everything, but also with justifying abominable behavior. What had previously been the sole purview of religion increasingly became the domain of science. This allowed the purveyors of racism to argue that Blacks lived in the conditions they did not because of any moral failings on the part of the perpetrators, but because it was the logical, natural order of things.
The Joy of Colors
Growing up in East Los Angeles, a Black child in a biracial family in a Latinx community, I understood that racist conditions existed and that police would shoot on sight people of my skin tone and darker. This meant that our late family friend, the former Black Panther Michael Zinzun, lost his eye to a police beating and had to sue an entire city to get some semblance of justice for it. This is simply the logic of the thing, our society. This is a structure built on logic.
That logic is both nonsensical and powerful in many ways, not only because of the formidable structures of white supremacy that are so heavily fortified by it but also because of the ways it limits our imaginations. It was only 13 years after getting a bachelor’s degree in physics, astronomy, and astrophysics, 11 years after getting a master’s in astrophysics, and six years after getting a doctorate in theoretical physics that I first asked myself: What is the physics behind melanin, that thing that has made all of this storytelling possible?
Discerning how artificial social structures have conditioned you not to ask basic and rather obvious questions is a harsh realization for a scientist, someone who has been trained to ask how the world works. When I asked my doctor why I was low on vitamin d, and he explained that it’s harder for darker-skinned people to get adequate amounts of sun in order to produce it, it didn’t occur to me to ask about the physics behind that. I looked into the medical side first and discovered that current vitamin d testing regimes might not even be good measures for people who have African heritage.
To understand why it is so stunning that this question never occurred to me, I have to explain spectra. The electromagnetic spectrum is the full range of frequencies that light has. These frequencies are most familiar to us humans in the form of the spectrum of colors that many but not all of us can see with our eyes. What the human eye can potentially detect is actually a small part of the electromagnetic spectrum, which also includes the microwaves that we use to rapidly heat our food; the x-rays we use to visualize the bones beneath our layers of skin, muscle, fat, and blood; and the cancer-causing UV rays from which our precious ozone layer and—importantly—our melanin protects us.
It turns out that due to quantum mechanics, every chemical in the periodic table of elements has a resonance with a particular part of the electromagnetic spectrum. For example, when we electrify sodium, it emits light with a characteristic wavelength of 589 nanometers, what many of us would call “orange.” Those of us who grew up in areas with orange street lamps have witnessed this phenomenon over and over: These are the sodium lamps that are now being phased out in favor of more energy-efficient (but frankly, ugly) white led lights. In reverse, if we point light with this wavelength at sodium, the sodium will absorb it and change quantum energy states.
My fascination with this dynamic between atoms and light started early in high school and continued through my junior-year quantum mechanics course in university, where I learned how to calculate their properties. In fact, I was so excited by spectra that I wrote my junior thesis on using them to study the properties of extrasolar planetary atmospheres, and I spent a summer building lasers, which are effectively just amplified spectral emissions in one frequency. And yet for all of this thinking, it was only recently, as a postdoctoral fellow, that I began to wonder: What is it in my skin that absorbs and emits light such that I am this color, this shade of brown that is on a spectrum of racialized Blackness? Now, as a more senior researcher who has begun to think deeply about the deployment of physics education, I realize that perhaps it is a bit odd that this never came up in my coursework. What could possibly relate physics to my life more than talking about the physics of my skin color? Of course, this would require from the scientific community a broad interest in helping someone like me relate to physics, an attitude that is not sufficiently abundant in the physics community.
Toward a True Science of Melanin
When I started to seek out information about the physics of melanin, I was surprised to discover that melanin is becoming an active topic of research in biophysics after a few centuries of what I would call halfhearted investigation by biologists and chemists. What might have been different if, for example, they hadn’t been distracted for about half a century by the pseudoscience of eugenics, which was considered foundational until the Holocaust helped some understand its social implications? Although openly eugenicist ideas are now considered fringe, it is still clear from anthropological studies of science that the biology of the disempowered—such as women of any race—is less likely to be studied. I was also pained but perhaps not entirely surprised to discover that one reason melanin has become so interesting of late is because so many (lighter-skinned) people are getting skin cancer.
In other words, after centuries of kidnapping, locking up, beating, raping, robbing, and killing people in large part on the basis of the human eye’s perception of skin melanin content, studying the mechanical nature of melanin—its interactions with light and its movement and production in the body—became interesting only when it seemed necessary for enhancing the survival of people who don’t have a lot of it in their skin.
Indeed, melanin is a fascinating biochemical system: In addition to its strong pigmentation, it also exhibits what we call broad UV band absorption. In other words, it absorbs ultraviolet radiation of a broad bandwidth of frequencies, and, in doing so, protects whatever is underneath the melanin from the harmful effects of those UV rays. It is a natural sunblock and for this reason alone is an interesting physical system to study, both from an evolutionary perspective and from the point of view of biophysics.
But as I delved into what we know about melanin—which is mostly what it seems to do and very little about how it manages to do this—I discovered that what I thought was interesting about melanin might be one of its least interesting features. I had assumed when I started out that what made melanin fascinating was its interaction with light—what it absorbed as a photoprotectant and what it reflected as a color visible to the human eye. I realize now that this belief was rooted in my own bias, both because I have a profound and admittedly irrational love of spectra and because I know that what police officers and vigilantes think they see is a matter of life and death.
But the substance used to justify so much death may also be the key to the future of materials technology. As described in Australian university graduate Clare Giacomantonio’s 2005 undergraduate thesis, melanin is an unusual conductor of electricity. It is unique because it is bioorganic in nature (as part of a living organism, humans), and it is disordered in nature, which means that sometimes it behaves like a mediator of electricity and sometimes it insulates against electricity. These flexible, superconductor-like properties appear to be mediated by contact with water and are quantum mechanical in nature.
To fully grasp them mathematically requires the use of chaos theory. Independent of real-world applications to developing new materials, they may provide us with insight into the fundamental interpretation of quantum mechanics, something else we are still working to understand. Indeed, quantum mechanics—that theory of physics that is so adamantly unintuitive—is at the heart of a visible property that Europeans randomly used to constitute an intuitive understanding of race. Significantly, melanin, the material that made eugenicists think people of African descent were inherently stupid, is also the stuff of Afro-Futurist techno-dreams.
Indeed, while the potential health applications of what we learn about melanin are compelling, a deeper understanding of melanin could be technologically transformative. Since melanin appears to be a relatively simple disordered conductor, it provides an opportunity to decode difficult concepts about this class of materials. This class includes superconductors, materials that allow electricity to flow through them without resistance. Implementing superconductors at large scales would minimize the loss of electricity when it is delivered from its source to households around the world, thus reducing the amount of energy required for societies to function. This sounds exciting, of course, but the existing materials work as superconductors only at temperatures near absolute zero. To introduce them into social use requires a technological capacity we do not currently have. Melanin may hold the key to delivering our green-energy future efficiently, if we make an ethical commitment to use the technology for the greater good.
Out of the chaos of the way bias has misguided biological science arises new possibilities of knowledge production. It is up to those of us who work in the fields of science, technology, and medicine to continuously raise the question of why it has taken us so long to recognize the spectacular and fascinating qualities of melanin that make it the object of research. Some of the answers are mundane: We have better technology for seeing small stuff now. Some of them are outrageous: Geneticists were so caught up in a eugenicist worldview that they were unable to actually do any useful research on melanin. But it is up to the physics community to thoroughly consider what these answers mean for our future as a collective of researchers who wish to understand how the world works. There is much to be learned from studying melanin, including how racism can derail our capacity to nurture discovery. Many questions remain, like whether the scientific community will do the hard work of ensuring that Black Americans, whether they have high concentrations of eumelanin in their skin or not, are welcome to become part of the research enterprise that will take our understanding of melanin out of the chaos and into the light.