Neil deGrasse Tyson on the Hidden Costs of a Cosmic Perspective

Neil deGrasse Tyson’s Astrophysics for People in a Hurry is a satisfying success of book. And in his last chapter, “Reflections on the Cosmic Perspective,” I think he raises an unexpected and difficult question: where do we fit in to all this astral splendor? He acknowledges that his fascination with the cosmos can be a distraction from earthly and humane concerns. Here are passages.

Wikipedia

       The cosmic view comes with a hidden cost. When I travel thousands of miles to spend a few moments in the fast-moving shadow during a total solar eclipse, sometimes I lose sight of Earth.

       When I pause and reflect on our expanding universe, with its galaxies hurtling away from one another, embedded within the ever stretching, four-dimensional fabric of space and time, sometimes I forget that uncounted people walk this earth without food or shelter, and that children are disproportionately represented among them….

       When I track the orbits of asteroids, comments, and planets, each one a pirouetting dancer in a cosmic ballet, choreographed by the forces of gravity, sometimes I forget that too many people act in wanton disregard for the delicate interplay of Earth’s atmosphere, oceans and land.…

       And sometimes I forget that powerful people rarely do all they can to help those who cannot help themselves. I occasionally forget those things because, however big the world is…the universe is even bigger.

     …[I] think of people not as the masters of space and time but as participants in a great cosmic chain of being, with a direct genetic link across species both living and extinct, extending back nearly four billion years to the earliest single-celled organisms on Earth….If a huge genetic gap separated us from our closest relatives in the animal kingdom, we could justifiably celebrate our brilliance. We might be entitled to walk around thinking we are distant and distinct from our fellow creatures. But no such gap exists. Instead we are one with the rest of nature, fitting neither above nor below, but within.

     [The cosmic perspective is] more than about what you know. It’s also about having the wisdom and insight to apply that knowledge to assessing our place in the universe.

     The cosmic perspective is humble….

     [It is] spiritual–even redemptive–but not religious….

     [It] enables us to grasp, in the same thought, the large and the small….

     [It] opens our eyes to the universe, not as a benevolent cradle designed to nurture life but as a cold, lonely, hazardous place, forcing us to reassess the value of all humans to one another….

     [It] not only embraces our genetic kinship with all life on Earth but also values our chemical kinship with any yet-to-be discovered life in the universe, as well as our atomic kinship with the universe itself.

In those last points—about the universe as a “lonely, hazardous place”  and at the same time that we can embrace our kinship to all of it, life included—Tyson hints at the tension that a unified cosmic perspective entails. Much as we wish it weren’t so, we are odd ducks in a dark, dangerous ocean. For Tyson, our best spiritual move is to find “kinships” wherever we can, with our atoms and our stars as well as with our ancestors.

Tyson’s discussion resonates for me, in a reversed sort of way. The astrophysicist finds his most satisfying meanings in the physics of the cosmos. This retired English teacher finds more to learn and more meaning in the history of living things. I am more drawn to the wily skills that plants use to survive than I am to the evolution of galaxies, though I recognize my “kinship” to them as well.

I think such preferences stem from the differences among us all in where we seek that which is greater-than-ourselves, that which is comforting-and-coherent. Perhaps such searches were less prone to fragmenting in the days when the deity or deities whom nearly all of us believed in provided the answers. The faces of the god or gods or their incarnations smoothed the way to a unified vision of the human condition within the universe.

Today, Tyson and others help fit together the strange, new, matter-and-energy pieces of a secular cosmic vision.

 

 

 

 

 

 

Our Actual “Eve”

She lived between 100,000 and 200,000 years ago in southern Africa. These days she is known as Mitochondrial Eve, but the “Eve” part is misleading. Unlike the Biblical Eve, she wasn’t the first woman nor was she the only woman alive at the time—and there were plenty of men around as well. Still, Mitochondrial Eve was an actual person. We don’t know much about her except that she is the most recent woman to whom every human today, male and female, can be traced back on his or her mother’s side—from daughter or daughters back to mother, back to the mother’s mother, and so on.

But interesting as such a linkage may be to scientists, how significant is Mitochondrial Eve for us? I’m not sure. See what you think.

Mitochondria produce energy. Originally independent cells themselves, they were engulfed by larger cells long ago and made themselves at home. They brought with them their own tiny DNA molecules that are unrelated to the DNA of the cell itself that make up our genes and reside in the cell nucleus.Mitochondria in a cell (Flickr)

Mitochondria in a typical cell. The long thread of genetic DNA in the nucleus is shown, but the unrelated DNA inside the mitochondria is not. (Flickr)

But the bits of DNA in the mitochondria, like genetic DNA, mutate over time; they change slightly as they copy themselves. These variations in a cell’s mitochondrial DNA were handed down through generations of pre-human primates and then early humans themselves, a trail of inheritance separate from our genes.

All of this is difficult to visualize. Here is a rough analogy. Automobiles have their own specialized energy component, the 12-volt battery that cranks the starter motor. Car batteries come in different brands and shapes with coded serial numbers and dates on them. Over the years, independently of yearly changes to cars themselves, battery manufacturers make changes to car batteries. Now imagine—it’s admittedly a stretch—that if you had no other way of knowing when a specific car model first went into production, you could get an approximate date by examining the style and code numbers on the car battery.

The variations in mitochondrial DNA serve a similar purpose. All humans inherit in only through their mothers. Males don’t pass theirs along. Why? Because the basic parts of our cells come from the woman’s ovum. Fathers deliver their genetic DNA by sperm to the egg, but the egg cell itself that divides into two cells, then four cells, and so on, is mom’s. Complete with her mitochondria.

Over the course of five thousand generations or so, women around the world passed their mitochondrial DNA, with its small but distinctive variations, to their daughters. Along the way, though, some mothers bore only sons and other women had no children at all. Gradually, all the variations of mitochondrial DNA fizzled out, except one. We all carry it, as did a woman a long time ago, Mitochondrial Eve. As if all lines of car batteries, in car models that changed or were discontinued, went out of production except one.

What to make of all this? Compared to the Biblical Eve and her list of firsts—first woman, first human to be curious, first mother—we have little to show for our ancestry from Mitochondrial Eve. And the merging of genetic DNA from our mother and father has by far a greater influence on who we are and what we’re like. By comparison, Mitochondrial Eve is just a woman a very long time ago whom we all happen to be linked with inconsequentially on our mother’s side.

Still, the biomedical historian Siddhartha Mukherjee writes in The Gene, “I find the idea of such a founding mother endlessly mesmerizing.” For Mitochondrial Eve is one of our Most Recent Common Ancestors—an MRCA. The MRCA for any group of organisms  is the individual after which later generations evolved in different directions. The MRCA of primates (humans as well as chimps, apes, monkeys, baboons) lived 65 million years ago. The MRCA of all animals lived 600 million years ago. And the MRCA of all living things, 3.6 billion years ago. For many people, interesting to know but not so easy to imagine.

But it is possible with some effort to envision the Most Recent Common Ancestor who looked a lot like us. Maybe Mitochondrial Eve’s value lies here: by thinking about her, we may be getting better at wrapping our heads around the reality of even older ancestors who seem impossibly ancient yet who made us what we are.