Too Short for a Blog Post, Too Long for a Tweet 520

 

Here are a few excerpts from a book I recently read, "Until the End of Time: Mind, Matter, and Our Search for Meaning in an Evolving Universe," by Brian Greene.

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,” 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.

Roughly fifty to one hundred million years after its birth, earth likely collided with a Mars-sized planet called Theia, which would have vaporized the earth’s crust, obliterated Theia, and blown a cloud of dust and gas thousands of kilometers into space. In time, that cloud would have clumped up gravitationally to form the moon, one of the larger planetary satellites in the solar system and a nightly reminder of that violent encounter. Another reminder is provided by the seasons. We experience hot summers and cold winters because earth’s tilted axis affects the angle of incoming sunlight, with summer being a period of direct rays and winter being a period of oblique ones. The smashup with Theia is the likely cause of earth’s cant. And though less sensational than a planetary collision, both the earth and the moon endured periods of significant pummelings by smaller meteors. The moon’s lack of eroding winds and its static crust have preserved the scars but earth’s thrashing, less visible now, was just as severe. Some early impacts may have partially or even fully vaporized all water on earth’s surface. Despite that, the zircon archives provide evidence that within a few hundred million years of its formation, earth may have cooled sufficiently for atmospheric steam to rain down, fill the oceans, and yield a terrain not all that dissimilar from the earth we now know. At least, that’s one conclusion reached by reading the crystals.

Every molecule of DNA is configured in the famous spiral of the double helix, a long twisting ladder whose rungs consist of pairs of struts, shorter molecules called bases, usually denoted A, T, G, and C (the technical names won’t matter for us, but these stand for adenine, thymine, guanine, and cytosine). Members of a given species mostly share the same sequence of letters. For humans, the DNA sequence runs about three billion letters long, with your sequence differing from that of Albert Einstein or Marie Curie or William Shakespeare or anyone else by less than about a quarter of a percent, roughly one letter out of every string of five hundred.23 But while basking in the glow of possessing a genome so similar to that of any of history’s most revered luminaries (or infamous villains), note that your DNA sequence also has a 99 percent overlap with any given chimpanzee’s. Minor genetic differences can have major impact.

The functions that keep a typical cell alive for just a single second require the energy stored in about ten million ATP molecules. Your body contains tens of trillions of cells, which means that every second you consume on the order of one hundred million trillion (1020) ATP molecules.

As I sit here, typing out my thoughts, I am unfazed by the realization that at the level of fundamental particles everything I’m thinking and everything I’m doing constitutes the unfolding of physical laws that are beyond my control. What matters to me is that unlike my desk and unlike my chair and unlike my mug, my collection of particles is able to execute an enormously diverse set of behaviors. Indeed, my particles just composed this very sentence and I’m pleased they did. Sure, that reaction, too, is nothing but my particle army carrying out their quantum mechanical marching orders, but that doesn’t diminish the reality of the feeling. I am free not because I can supersede physical law, but because my prodigious internal organization has emancipated my behavioral responses.

During our inquiry into the origin of language, one proposal featured the role of gossip in maintaining hierarchies and fostering alliances. Frivolous as such conversation may be viewed in the modern age, psychologist Jesse Bering places gossip at the nexus of religion’s adaptive role in the ancient world. Before we acquired the capacity to speak, a rogue in our midst might misbehave—stealing food, borrowing sexual partners, hanging back during the hunt—but if the witnesses to the transgression were small in number and weak in status the culprit could get away scot-free. Once language took hold, that changed. With even a single but widely discussed infraction, the culprit’s reputation would suffer and reproductive opportunities would plummet. Bering’s suggestion is that if a would-be transgressor imagines that there is always a powerful witness—hovering in the wind, or in trees, or in the sky—he would be less likely to transgress, less likely to be fodder for unfavorable gossip, and less likely to become a social outcast. Consequently, he would be more likely to have offspring and pass on his god-fearing instincts. A predisposition for religion protects his genetic lineage and so becomes self-perpetuating.

The light each galaxy emits does travel through space. And much as a kayaker will be stymied if she’s paddling upstream at a speed that’s less than that of the stream itself, the light emitted by a galaxy that is sprinting away at superluminal speed will fight a losing battle as it tries to reach us. Traversing space at light speed, the light cannot overcome the faster-than-light-speed increase in the distance to earth. As a result, when future astronomers look past nearby stars and focus their telescopes on the deepest parts of the night sky, all they will see is velvety black darkness. The distant galaxies will have slipped beyond the bounds of what astronomers call our cosmic horizon. It will be as if the distant galaxies have dropped off a cliff at the edge of space.

I’ve focused on distant galaxies because those that are relatively nearby, a cluster of about thirty galaxies known as the Local Group, will continue to be our cosmic companions. Indeed, by the eleventh floor, the Local Group, dominated by the Milky Way and Andromeda galaxies, will likely have merged, an anticipated future union astronomers have christened Milkomeda (I would have lobbied for Andromilky). The stars of Milkomeda will all be close enough for their mutual gravitational pulls to withstand the expansion of space and keep the stellar collection intact. But our severed contact with the more distant galaxies will be a profound loss. It was through careful observations of distant galaxies that Edwin Hubble first realized that space is expanding, a discovery confirmed and refined by a century of subsequent observations. Without access to the distant galaxies, we will lose a primary diagnostic tool for tracing spatial expansion. The very data that guided us toward our understanding of the big bang and cosmic evolution will no longer be available.