Seeing dark matter as the key to the universe — and human empathy
On the last day of my residence at the artists’ colony Yaddo, I shared with my co-residents an excerpt from my book, “Dark Matter and the Dinosaurs.’’ I read from the first chapter, in which I liken dark matter — matter present throughout the universe that is invisible to us because it doesn’t emit or absorb light — to other entities that remain unnoticed but influence the workings of the world, from the bacterial cells in our bodies, which outnumber human cells by a factor of ten, to the myriad Internet communities and subcultures that thrive outside our awareness. The goal was to illuminate the gap between our limited observations and the many barely perceived phenomena that permeate our reality.
I was gratified to observe the audience’s increased comfort with dark matter and its unseen but important influences. But the most surprising and rewarding response came the following day, when Jefferson Pinder, a young African-American artist, stopped me as I was leaving and asked, “I know this might sound like a crazy question, but were you really talking about race?”
The crazy thing is that I was. People’s attitude toward dark matter is bedeviled by the same instincts that influence their responses to different races, castes, or classes whom they might not truly see but who are nonetheless essential to society. Jefferson understood that the real issue I was addressing was the transparency — both metaphorical and literal — of people, phenomena, particles, and forces that we don’t necessarily appreciate but that are important to our shared reality.
The metaphor returned in a different guise in a seminar I teach at Harvard, which I begin with a discussion of how science advances, and how the optimal scientific description can depend on the frame of reference. The students relished the science, but the classroom discussion also took a surprising turn — into questions of empathy.
Race and class differences call for empathy largely because of our difficulties in understanding what we can’t experience or see, including the often hidden cultural forces that animate other people and their communities. Such blindspots challenge us in the scientific realm too — but in ways that are usually more obvious and readily acknowledged. The world looks entirely different at the scale of the atom — or the Higgs boson — than it does when viewed from your chair or from space. This is why the rules of quantum mechanics can appear unintuitive or illogical. Their unfamiliarity makes them difficult to comprehend.
People relate best to scales they encounter in their daily lives, perhaps a millimeter to a kilometer in size — the scale our brain’s visual system readily processes via optical wavelengths. As science and technology advance, sophisticated measuring instruments allow us to explore distances increasingly removed from our immediate experience. But our human blinders endure — the greater that distance, the more irrelevant the phenomena tend to seem.
Relating to a scale outside our grasp, be it in scientific measurements or in cultural dynamics, requires a deliberate effort to squint at, or find less direct means of observation of, what appears irrelevant at familiar scales but is a fundamental force in the reality of the
Dark matter is the dominant form of matter in the universe — it carries five times as much energy as ordinary matter. Yet people tend to perceive it as irrelevant or even dangerous, thanks to the ominous-sounding name that bespeaks this very bias.
Dark matter neither resembles nor strongly interacts with the matter we experience in our daily lives. Although ordinary matter carries a small percentage of the universe’s energy, it influences itself and its surroundings much more palpably than dark matter, which just passes through the things we can see and touch. Ordinary matter makes up everything we sense directly — the medium via which you are consuming these very ideas, the neurons with which you’re processing them, and the chair on which you’re sitting while doing so.
Yet, just as a small fraction of the world’s political and economic elite dominates the vast majority of power while the remaining population provides essential infrastructure that gives shape to daily life — constructing our homes, keeping our cities operational, getting food to our tables — dark matter was essential to the structure and formation of the universe. It was crucial in the creation of the clusters and galaxies without which our world would never have arisen.
Dark matter’s existence perplexes people who find it implausible that the vast majority of matter in the universe would be undetectable by our senses and their technological extensions. Some even wonder if it’s a sort of mistake. To me it would be even more astonishing if the matter we can see with our eyes were all the matter there is. You might have thought such hubristic beliefs were upended by the Copernican Revolution. After all, the history of physics is the history of revealing how much is deceptive, or is hidden from view.
Most people mistake their own perspective, shaped by their subjective and limited perception, for the absolute reality of the external world. Questioning this assumption is what advanced our research on dark matter. It is also the only thing that has ever advanced human empathy.
Recognizing the limitations of our senses and the subjectivity of our experiences is the only route to transcending them. As David Foster Wallace explained in his Kenyon College commencement address, we can’t help but see the world from our own point of view. Our limited perspective makes us forget that the human experience is a vast locus of points of which we are but one. Empathy is difficult. It is also crucial to the progress of both science and society. It demands that we make a deliberate and consistent effort to step out of our familiar frames of reference. Only then can we synthesize different perspectives, observations, and experiences — the very act at the heart of creativity, which will be essential to solving the increasingly complex problems that beset our world.
Lisa Randall is professor of physics at Harvard and author of “Dark Matter and the Dinosaurs: The Astounding Interconnectedness of the Universe,’’ which will be released Tuesday.