Until the End of Time Page 3

  On reflection, neither was the case. We are the product of a long lineage that has soothed its existential discomfort by envisioning that we leave a mark. And the more lasting the mark, the more indelible its imprint, the more a life seems to be a life that mattered. In the words of philosopher Robert Nozick—but they could just as easily have come from George Bailey—“Death wipes you out…To be wiped out completely, traces and all, goes a long way toward destroying the meaning of one’s life.”7 Especially for those, like me, without a traditional religious orientation, an emphasis on not being “wiped out,” a relentless focus on endurance, can pervade everything. My upbringing, my education, my career, my experiences have all been informed by it. During every stage, I’ve gone forward with an eye trained on the long view, on seeking to accomplish something that would last. There is no mystery why my professional preoccupation has been dominated by mathematical analyses of space, time, and nature’s laws; it is hard to imagine another discipline that more readily keeps one’s day-to-day thoughts focused on questions that transcend the moment. But scientific discovery itself casts this perspective in a different light. Life and thought likely populate a minute oasis on the cosmic timeline. Though governed by elegant mathematical laws that allow for all manner of wondrous physical processes, the universe will play host to life and mind only temporarily. If you take that in fully, envisioning a future bereft of stars and planets and things that think, your regard for our era can appreciate toward reverence.

  And that is the feeling I had experienced at Starbucks. The calm and connection marked a shift from grasping for a receding future to the feeling of inhabiting a breathtaking if transient present. It was a shift, for me, compelled by a cosmological counterpart to the guidance offered through the ages by poets and philosophers, writers and artists, spiritual sages and mindfulness teachers, among countless others who tell us the simple but surprisingly subtle truth that life is in the here and now. It’s a mind-set that is hard to maintain but one that has infused the thinking of many. We see it in Emily Dickinson’s “Forever—is composed of Nows”8 and Thoreau’s “eternity in each moment.”9 It is a perspective, I’ve found, that becomes all the more palpable when we immerse ourselves in the full expanse of time—beginning to end—a cosmological backdrop that provides unmatched clarity on how singular and fleeting the here and now actually is.

  The purpose of this book is to provide that clarity. We will journey across time, from our most refined understanding of the beginning to the closest science can take us to the very end. We will explore how life and mind emerge from the initial chaos, and we will dwell on what a collection of curious, passionate, anxious, self-reflective, inventive, and skeptical minds do, especially when they notice their own mortality. We will examine the rise of religion, the urge for creative expression, the ascent of science, the quest for truth, and the longing for the timeless. The deep-seated affinity for something permanent, for what Franz Kafka identified as our need for “something indestructible,”10 will then propel our continued march toward the distant future, allowing us to assess the prospects for everything we hold dear, everything constituting reality as we know it, from planets and stars, galaxies and black holes, to life and mind.

  Across it all, the human spirit of discovery will shine through. We are ambitious explorers seeking to grasp a vast reality. Centuries of effort have illuminated dark terrains of matter, mind, and the cosmos. During millennia to come, the spheres of illumination will grow larger and brighter. The journey so far has already made evident that reality is governed by mathematical laws that are indifferent to codes of conduct, standards of beauty, needs for companionship, longings for understanding, and quests for purpose. Yet, through language and story, art and myth, religion and science, we have harnessed our small part of the dispassionate, relentless, mechanical unfolding of the cosmos to give voice to our pervasive need for coherence and value and meaning. It is an exquisite but temporary contribution. As our trek across time will make clear, life is likely transient, and all understanding that arose with its emergence will almost certainly dissolve with its conclusion. Nothing is permanent. Nothing is absolute. And so, in the search for value and purpose, the only insights of relevance, the only answers of significance, are those of our own making. In the end, during our brief moment in the sun, we are tasked with the noble charge of finding our own meaning.

  Let us embark.

  2

  THE LANGUAGE OF TIME

  Past, Future, and Change

  On the evening of January 28, 1948, nestled between a performance of the Schubert Quartet in A minor and a presentation of English folk songs, BBC Radio broadcast a debate between one of the most potent intellectual forces of the twentieth century, Bertrand Russell, and Jesuit priest Frederick Copleston.1 The topic? The existence of God. Russell, whose innovative writings in philosophy and humanitarian principles would earn him the 1950 Nobel Prize in Literature, and whose iconoclastic political and social views would earn him a pink slip from both Cambridge University and the City College of New York, provided numerous arguments for questioning, if not rejecting, the existence of a creator.

  One line of thought that informed Russell’s position is relevant to our exploration here. “So far as scientific evidence goes,” Russell noted, “the universe has crawled by slow stages to a somewhat pitiful result on this earth and is going to crawl by still more pitiful stages to a condition of universal death.” With such a bleak outlook, Russell concluded, “if this is to be taken as evidence of purpose, I can only say that the purpose is one that does not appeal to me. I see no reason, therefore, to believe in any sort of God.”2 The theological thread will be stitched into later chapters. Here, I want to focus on Russell’s reference to scientific evidence for a “universal death.” It comes from a nineteenth-century discovery with roots as humble as its conclusions are profound.

  By the mid-1800s, the Industrial Revolution was in full swing and across a landscape of mills and factories the steam engine had become the workhorse driving production. Nevertheless, even with the critical leap from manual to mechanical labor, the efficiency of the steam engine—the useful work performed compared to the quantity of fuel consumed—was meager. Roughly 95 percent of the heat generated by burning wood or coal was lost to the environment as waste. This inspired a handful of scientists to think deeply about the physical principles governing steam engines, seeking ways to burn less and get more. Over the course of many decades their research gradually led to an iconic result that has become justly famous: the second law of thermodynamics.

  In (highly) colloquial terms, the law declares that the production of waste is unavoidable. And what makes the second law vitally important is that while steam engines were the catalyst, the law is universally applicable. The second law describes a fundamental characteristic inherent in all matter and energy, regardless of structure or form, whether animate or inanimate. The law reveals (loosely, again) that everything in the universe has an overwhelming tendency to run down, to degrade, to wither.

  Stated in these everyday terms you can see where Russell was coming from. The future seemingly holds a continued deterioration, a relentless conversion of productive energy into useless heat, a steady draining, so to speak, of the batteries powering reality. But a more precise understanding of the science reveals that this summary of where reality is headed obscures a rich and nuanced progression, one that has been under way since the big bang and will carry onward to the far future. It is a progression that helps explain our place in the cosmic timeline, clarifies how beauty and order can be produced against a backdrop of degradation and decay, and also offers potential ways, exotic though they may be, to sidestep the bleak end Russell envisioned. As it is this very science, involving concepts such as entropy, information, and energy, that will guide much of our journey, it is worth our while to spend a little time understanding it more fully.

  Steam Engines

  Far be it from me to suggest that the meaning of life will be found lurking in the sweaty depths of a clamorous steam engine. But understanding the steam engine’s capacity to absorb heat from burning fuel and use it to drive recurrent motion in a locomotive’s wheels or a coal mine’s pump proves indispensable to grasping how energy—of any sort and in any context—evolves over time. And the way energy evolves has a deep impact on the future of matter, mind, and all structure in the universe. So let’s descend from the lofty realms of life and death and purpose and meaning to the incessant chugging and clanking of an eighteenth-century steam engine.

  The scientific basis of the steam engine is simple but ingenious: Water vapor—steam—expands when heated and so pushes outward. A steam engine harnesses this action by heating a canister filled with steam that is capped by a snuggly fitting piston free to slide up and down along the canister’s inner surface. As the heated steam expands, it pushes forcefully against the piston, and that outward thrust can drive a wheel to turn, or a mill to grind, or a loom to weave. Then, having expended energy through this outward exertion, the steam cools and the piston slides back to its initial position, where it stands ready to be pushed when the steam is heated again—a cycle that will repeat so long as there is burning fuel to heat the steam anew.3

  While history records the steam engine’s central role in the Industrial Revolution, the questions it raised for fundamental science were just as significant. Can we understand the steam engine with mathematical precision? Is there a limit to how efficient its conversion of heat into useful activity can be? Are there aspects of the steam engine’s basic processes that are independent of the details of mechanical design or materials used and thus speak to universal physical principles?

  In puzzling ov
er these issues, the French physicist and military engineer Sadi Carnot launched the field of thermodynamics—the science of heat, energy, and work. You wouldn’t have known it from sales of his 1824 treatise, Reflections on the Motive Power of Fire.4 But while slow to catch on, his ideas would inspire scientists over the course of the following century to develop a radically new perspective on physics.

  A Statistical Perspective

  The traditional scientific perspective, handed down in mathematical form by Isaac Newton, is that physical laws provide ironclad predictions for how things move. Tell me the location and velocity of an object at a particular moment, tell me the forces that are acting upon it, and Newton’s equations do the rest, predicting the object’s subsequent trajectory. Be it the moon pulled by earth’s gravity or a baseball you just whacked toward center field, observations have confirmed that these predictions are spot-on accurate.

  But here’s the thing. If you took high school physics, perhaps you will recall that when we analyze the trajectories of macroscopic objects we generally, if quietly, invoke a great many simplifications. For the moon and the baseball we ignore their internal structure and imagine that each is just a single massive particle. It’s a coarse approximation. Even a grain of salt contains about a billion billion molecules, and that’s, well, a grain of salt. Yet as the moon orbits we generally don’t care about the jostling motion of one or another molecule inhabiting the dusty Sea of Tranquility. As the baseball soars, we don’t care about the vibration of one or another molecule residing in its cork core. The overall movement of the moon or the baseball as a whole is all we’re after. And for that, applying Newton’s laws to these simplified models does the trick.5

  These successes highlight the challenge faced by nineteenth-century physicists concerned with steam engines. The hot steam pushing against the engine’s piston comprises an enormous number of water molecules, perhaps a trillion trillion particles. We can’t ignore this internal structure as we do in our analysis of the moon or the baseball. It is the motion of these very particles—slamming into the piston, bouncing off its surface, hitting the walls of the container, streaming back toward the piston again—that lies at the heart of the engine’s workings. The problem is that there is no way that anyone, anywhere, however smart they may be and however formidable the computers they may use, can calculate all of the individual trajectories followed by such an enormous collection of water molecules.

  Are we stuck?

  You might think so. But as it turns out, we are saved by a change in perspective. Large collections can sometimes yield their own powerful simplifications. It is surely difficult, impossible really, to predict exactly when you will next sneeze. However, if we broaden our view to the larger collection of all humans on earth, we can predict that in the next second there’ll be roughly eighty thousand sneezes worldwide.6 The point is that by shifting to a statistical perspective, earth’s large population becomes the key—not the obstacle—to predictive power. Large groups often display statistical regularities absent at the level of the individual.

  An analogous approach for large groups of atoms and molecules was pioneered by James Clerk Maxwell, Rudolf Clausius, Ludwig Boltzmann, and many of their colleagues. They advocated jettisoning detailed consideration of individual trajectories in favor of statistical statements describing the average behavior of large collections of particles. They showed that this approach not only makes calculations mathematically tractable, but the physical properties it can quantify are the very ones that matter most. The pressure pushing on a steam engine’s piston, for instance, is hardly affected by the precise path followed by this or that individual water molecule. Instead, the pressure arises from the average motion of the trillions upon trillions of molecules that slam into its surface each second. That’s what matters. And that’s what the statistical approach allowed the scientists to calculate.

  In our current era of political polls, population genetics, and big data more generally, the shift to a statistical framework might not sound radical. We’ve grown accustomed to the power of statistical insights extracted from studying large groups. But in the nineteenth and early twentieth centuries, statistical reasoning was a departure from the rigid precision that had come to define physics. Bear in mind, too, that up through the early years of the twentieth century there were still well-respected scientists who challenged the existence of atoms and molecules—the very basis of a statistical approach.

  Notwithstanding the naysayers, it didn’t take long for statistical reasoning to prove its worth. In 1905, Einstein himself quantitatively explained the jittery motion of pollen grains suspended in a glass of water by invoking the continual bombardment by H2O molecules. With that success, you had to be one heck of a contrarian to doubt the existence of molecules. What’s more, a growing archive of theoretical and experimental papers revealed that conclusions based on statistical analyses of large collections of particles—describing how they bounce around containers and thereby exert pressure on this surface, or acquire that density, or relax to that temperature—matched data so exquisitely that there was simply no room to question the explanatory power of the approach. The statistical basis for thermal processes was thus born.

  This was all a great triumph and has allowed physicists to understand not only steam engines but also a broad range of thermal systems—from earth’s atmosphere, to the solar corona, to the vast collection of particles swarming within a neutron star. But how does this relate to Russell’s vision of the future, his prognostication of a universe crawling toward death? Good question. Hang tight. We’re getting there. But we still have a couple of steps to go. The next is to use these advances to shed light on the quintessential quality of the future: it differs profoundly from the past.

  From This to That

  The distinction between past and future is at once basic and pivotal to human experience. We were born in the past. We will die in the future. In between, we witness innumerable happenings that unfold through a sequence of events that, if considered in reverse order, would appear absurd. Van Gogh painted Starry Night but could not then lift the swirling colors through reverse brushstrokes, restoring a blank canvas. The Titanic scraped along an iceberg and ripped open its hull but could not then reverse engines, retrace its path, and undo the damage. Each one of us grows and ages but we cannot then turn back the hands of our internal clocks and reclaim our youth.

  With irreversibility being so central to how things evolve, you would think we could easily identify its mathematical origin within the laws of physics. Surely, we should be able to point to something specific in the equations that ensures that although things can transform from this to that, the math forbids them from transforming from that to this. But for hundreds of years the equations we’ve developed have failed to offer us anything of the sort. Instead, as the laws of physics have been continually refined, passing through the hands of Newton (classical mechanics), Maxwell (electromagnetism), Einstein (relativistic physics), and the dozens of scientists responsible for quantum physics, one feature has remained stable: the laws have steadfastly adhered to a complete insensitivity to what we humans call future and what we call past. Given the state of the world right now, the mathematical equations treat unfolding toward the future or the past in exactly the same way. While that distinction matters to us, profoundly so, the laws shrug at the difference, assessing it as of no greater consequence than a stadium’s game clock ticking off time elapsed or time remaining. Which means that if the laws allow for a particular sequence of events to occur, then the laws necessarily permit the reverse sequence too.7