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The visible stars that fill the night sky can’t move faster than 600 miles per second or they would escape the gravitational clutches of the Milky Way, never to return. Speeds like 1,400 miles per second—meaning you could go from Coney Island to Hollywood in the time it takes to say, “Got your seat belt on, honey?”—were bewildering in 1929. Yet such motion was couch-potato leisurely compared to what the next-gen postwar telescopes would reveal soon enough.

  The newly observed speeds were breathtaking and also dispiriting. It became obvious—and remains so today—that no matter what system of propulsion is invented in the future, we will never visit the vast majority of galaxies: they are fleeing faster than we can ever hope to approach them.

  The Sombrero galaxy, containing two hundred billion stars, rushes away from us at 562 miles a second. (Matt Francis)

  Hale, still not finished despite suffering years of serious health problems (to which he finally succumbed in 1938), raised money for the next colossus, the two-hundred-inch telescope on Palomar Mountain in Southern California. It opened in 1949 and had a light-gathering mirror as wide as a living room. Palomar remained the world’s largest telescope for the next quarter century.

  Still, Carnegie astronomers had long wanted an observing station in the Southern Hemisphere so they could access the many mysterious objects hidden over California’s horizon. In the 1980s they reluctantly abandoned their custody of Mount Wilson, from which stars now appeared dimmer than those in nearby Hollywood, thanks to runaway development and a yearly 10 percent growth in the number of streetlights.3 Instead, they looked to another site—a mountain in the Andes that the Carnegie Institution had acquired in 1969, when the peso exchange rate was so low that you could buy a genuine sugar-filled Coke for three cents. Named Las Campanas—“the bells”—the observatory soon became the institution’s main facility, on which it constructed two of the world’s largest telescopes.

  The twin 250-inch giants were completed in 2002. Collectively called the Magellan Telescopes, they boast reflectors that are remarkable for their picture-window half-degree fields of view that can take in the entire moon in a single photograph. The exquisite images come courtesy of unique computer-driven pistons that deform the mirrors twice a minute to maintain their perfect parabolic shapes. Equally renowned is the site’s rock-steady image quality, unsurpassed in the world. It might as well be outer space.4

  Such a top-tier research center allows no casual visitors, but I knew I could use my astronomy press credentials to spend a few nights up there. It’s the ideal place from which to probe the fastest speeds in the universe. After I chatted with Wendy Freedman, whom I called at her office in Pasadena, arrangements were made. I headed for South America.

  The seemingly endless flight to Santiago was followed by good fortune. Las Campanas’s director was in town, and thus I met Dr. Miguel Roth for dinner at an outdoor table in one of the many beautiful neighborhoods of that fascinating city. Director for seventeen years, Roth is obviously very proud of the facility: “We’re up at eighty-five hundred feet, and it’s really dark. The site is incomparable. We get three hundred clear nights a year. The Atacama Desert stretches all around. The nearest corner store is one hundred miles away.”

  Two days later, after an unnerving flight that skimmed past the Andes’ jagged snowy peaks, and after glancing around the cabin to appraise the potential tastiness of my fellow passengers, I arrived in the lovely seaside resort town of La Serena, home of the Las Campanas headquarters. That year, the staff was spending much of its time seeking supernovas, whose reliable “standard candle” brightnesses help determine exact galactic distances, which in turn lets scientists understand how the universe’s expansion changes with time. This, then, is the Carnegie Observatories’ main current quest—to decipher the fate of the universe!

  And thus we reach the meat of this matter. It is nothing less than the greatest conundrum in all of science, and it revolves around speed. Happily, it can be simply stated. The Hubble constant—the speed at which galaxies rush away from us—mysteriously changed six billion years ago, when the universe was half its current age. Galaxy clusters started increasing their flyaway speeds, as if they all had rocket engines that suddenly ignited. The cause is often called dark energy, but that term is no more than a label affixed to an enigma first uncovered in 1998. As Wendy Freedman said with a sigh, “It’s very difficult to explain. It’s a perplexing mystery.”

  With a quick revision reminiscent of the hastily airbrushed deletions in Soviet encyclopedias, cosmologists abruptly rewrote their “basics of the universe” handbook. Three-quarters of the cosmos was now exclusively reserved for some kind of weird antigravity entity whose existence was utterly unsuspected a year earlier. Probing its powerful effects became a sudden, urgent focus for astronomers. I suspected that this quest, above all, was what occupied those who awaited me atop that Chilean mountain.

  The next day I left La Serena in a rented car heading northbound on a sparsely traveled section of the Pan-American Highway. The road immediately entered the southern edge of the vast Atacama Desert, the driest place on earth. Two desolate hours later I turned onto a relentlessly climbing dirt trail, passing wild burros and an animal called a viscacha, which looks like a cross between a squirrel and a rabbit and which seemed like a hallucination. The broad, bone-dry summit of Las Campanas was dotted with white domes. The high altitude and low humidity created a cloudless azure sky.

  I had arrived at noon. Perfect timing. This is when everyone has just awakened. All freshly showered and hungry, they file into the spacious dining hall like some religious cult. Their language resembles English, but the dialect is peppered with esoteric astrophysical terms.

  Astronomers Dan Kelson and Barry Madore, Wendy Freedman’s husband, sat with me. It was a precious opportunity, and I wasted no time plunging into profound issues involving cosmic velocity and what it might imply for the future of the universe. “I’m here for the ride,” Madore said with a modest laugh. “I’m not here for ultimate answers.”

  But later, under the stars, he turned serious. “We’re living with uncertainty with the universe’s expansion,” he said after I’d joined him in an enormous dome whose humming computer fans and drive motors formed the sound track to our conversation. The uncertainty involved not just when the cosmos went from slowing down to speeding up but also whether the acceleration would continue or even ultimately reverse itself. Still, I thought, if a little uncertainty was the worst he had to deal with, he shouldn’t complain. Wasn’t it enough that humans dared scratch the surface of these fastest of all velocities? Entire cities of suns that speed fifty thousand miles farther away from us each second?

  I was happy that such a major facility devoted its resources—a legacy of generous endowments that started with Andrew Carnegie’s fortune—to such a seemingly intractable quest, and I said so.

  When asked to compare Las Campanas to publicly funded instutions, Madore said, “This Magellan telescope costs forty thousand dollars a night to operate. But we can still be playful and innovative and take some risks. That’s one big difference. The national observatories, like Kitt Peak—they’re all risk-averse. Here it’s a thrill a day.”

  Night had brought a nourishing darkness to the Andes and the unseen black desert below us. The Milky Way—whose name had probably not taxed the astronomy muse—was astoundingly brilliant, with richly mottled detail, as in a pointillist painting. It dominated the Chilean night.

  Now, on the catwalk outside one of the 6.5-meter giant telescopes, Miguel Roth joined me, and we gazed up like the Mesoamericans of old, who regarded the Milky Way as the center of all existence.

  Miguel had given me carte blanche to roam, so I drove as instructed, with just my fog lights on, along the curvy mountain road that has no guardrails, violating every rule in the driver’s ed handbook. I went from one dome to another and visited the researchers in each. At one of the 6.5-meter instruments, I found exactly what I’d been seeking. Here the faint light from dist
ant galaxies, amplified and enhanced one million times by the huge, twenty-foot-wide telescope mirrors, had been accumulating for hours but still had nine hours more to go; astronomers had nothing to do but wait and chat.

  My lunch companion, Dan Kelson, was gathering the light from galaxies eight billion light-years away. He noticed my reporters’ notebook and started explaining: “This instrument is measuring four thousand galaxies at once. It’s an all-you-can-eat type of data collection.”

  He was used to this endless cycle of data harvesting followed by intense analysis. A brilliant and articulate thirty-eight-year-old from Illinois, he had helped pioneer the new technique of cutting thousands of precisely positioned slits into a metal plate so that a particular group of galaxies can be analyzed simultaneously. If there was anything noteworthy about one city of suns floating in a field of thousands, like a single sunflower in a van Gogh painting, it would immediately pop out to be flagged for further study.

  “When I was seven or eight my grandparents got me a refracting telescope from Sears,” he later told me. “I studied the lore of each constellation. I read every astronomy book in my elementary school’s library.”

  He was hooked. Kelson earned his doctorate at the University of California, where he simultaneously met his future wife and pursued his parallel obsession with making ice cream: he consumed hundreds of quarts annually.

  But all those kilos of saturated fat didn’t slow Kelson’s passion. His dissertation research involved many nights on the new telescopes at the Keck Observatory, atop Hawaii’s Mauna Kea, as well as analyzing Hubble Space Telescope data.

  He was exactly the kind of person to whom Hubble would have wanted to pass the torch—exactly the right man to clarify Hubble’s bombshell of an exploding universe. His ability to merge cutting-edge spectral techniques with digital analysis formed the ideal skill set with which to follow the galactic footsteps of the legendary long-gone Carnegie astronomers.

  By the first light of dawn, Kelson would be detecting objects rushing away from us at the astounding speed of 112,000 miles per second. That is more than half the speed of light. Kelson had in fact, some years earlier, discovered the farthest and fastest galaxy ever known. And his team did it again in 2013, making headlines around the world.

  Some of that night’s dimmest smudges might lie at the very edges of the observable universe and be the fastest objects humans can ever see. This is the outer boundary of velocity—the motion envelope within which everything else dwells.5

  And yet, astonishingly, these galaxy clusters aren’t really moving at all. Rather, the space between us and them is inflating. The galaxies are just sitting inertly, like Scrabble players waiting for a vowel. Each is gravitationally jostled by its companion galaxies, but the truly ultrafast speeds we see are an expanding-space phenomenon.

  Of course, one might wonder how, if space is mere emptiness, it can expand on its own. How can nothingness do anything? Even with a mandate to explore all manner of motion, it’s still odd to discuss the animation of nothingness.

  But space is not nothing. There’s no such thing as nothing. Turns out space has properties. Virtual particles—subatomic particles that live for evanescently tiny time periods and then vanish—pop in and out of existence. Nothingness has inherent energy, and lots of it. According to current theory, an empty mayonnaise jar containing only vacant space has enough energy to boil away the Pacific Ocean in less than a second.

  This so-called vacuum energy, or zero-point energy, pervades the cosmos. Thus seeming nothingness seethes with power. And whatever it is, it grows bigger and bigger.

  Square one in our natural-motion board game, therefore, involves not just the very fastest velocities but also the frenzied animation of emptiness.

  The most frequent question cosmologists get is: What is the universe expanding into?

  For many, it’s the most perplexing motion-related inquiry, and scientists hear it routinely. However, to ask such a question means you’ve pictured the universe as an inflating balloon that you’re viewing from the outside. In actuality, no such perspective exists. There is no “outside” to the universe, by definition. The conundrum arises because the questioner has set up a nonexistent vantage point.

  Instead, one should visualize living within a galaxy cluster and observing all the others. We see them all flying directly away from us. Distances between clusters are growing everywhere. This is the basic truth, and we can all picture it. And whether we deem the galaxies to be moving or the space between there and here to be inflating, the result is the same. The gap between us and distant galaxies is steadily growing.6

  Moreover, the rate of the universe’s size increase is itself growing. We’re living within an ever more powerful self-perpetuating explosion. Most astronomers think it’s caused by that mysterious antigravity force pervading every cosmic nook and cranny, dark energy, which keeps rearing its invisible head. That’s probably what started everything blowing outward from the get-go. In a very real sense, the big bang is still banging. This runaway mushrooming of the entire universe is the picture frame that surrounds all other movement.7

  Our exploding universe, which also contains small regions of contracting, collapsing entities, results from a tug-of-war between phantoms in black robes, in which dark matter does most of the pulling and dark energy does the repelling. The latter is winning the contest. Dark energy first gained the upper hand six billion years ago, even if we only just learned the news around the time we were switching from dial-up to broadband.

  If we could someday gain light-speed capability, which physicists assure us is impossible, we still couldn’t reach the farthest visible galaxies, not even if we traveled forever. Thanks to the acceleration of the expanding universe, by the time we arrived at the galaxies’ present location, which would require more than thirty billion tedious years in our spaceship, the distance between us would have increased so enormously that they’d be farther away than ever. Here is futility beyond even the petty frustrations of Sisyphus.

  Indeed, the light of those galaxies we were trying so hard to reach would no longer be visible. The trip would be worse than pointless. Our quarry would simply have vanished without a trace.

  Lest we let ourselves feel too crushed by this news, within these dizzying extreme-motion cosmic parameters lie astounding secrets we have uncovered. Kelson himself promised to reveal some when his data was complete. But, as I was to learn, the true story of nature’s motions and speeds did not unfold without laughable errors, egotistical ambitions, and unspeakable tragedy.

  The mistakes and the head-scratching began long ago. The oldest Hindu religious text, the Rigveda, written in Sanskrit around 1500 BCE, pondered how it is that “the waters glide downward to the ocean.” By the time Old Testament books were penned, a key point was not motion but its opposite. Psalm 93:1 says, “The world also is established, that it cannot be moved.” The universal assumption was of a stationary earth. The sun circling around us while our planet remains motionless seemed beyond dispute, because even an idiot could watch it happen. You could see stuff in the sky moving, and you could feel that we were not moving.

  The standard wisdom was that, as in everyday life, the fastest-seeming objects must be those closest to us. (A car going down your street changes its angular position faster than a plane in the sky.) To the ancients this meant that the moon must be closer to us than the stars. It daily traverses twenty-six of its own widths as it speeds through the constellations. At the other extreme were the six thousand glowing dots whose patterns never changed; they must lie farthest away. This assigning of distance—the moon nearest and the stars farthest—ultimately proved true. So the ancients managed not to be wrong about everything.

  By the time of the Greeks, the stars that circled us nightly were assumed to be inlaid into a kind of crystalline sphere—check another box in the “incorrect” column. But with the tools at hand 2,300 years ago—i.e., none—how could anyone begin to figure out the truth?
r />   Yet that is exactly what one Greek accomplished. I introduce him proudly, because he is my first hero.

  Aristarchus of Samos, born in 310 BCE, pondered these moving entities in the sky and arrived at correct conclusions eighteen centuries ahead of everyone else. A mathematician and astronomer, Aristarchus was the very first person to say that the sun is the center of the solar system. And that Earth orbits around it while also spinning like a top. To his contemporaries it must have seemed nothing short of crazy. And indeed, with fellow Greeks Plato and Aristotle contradicting and even ridiculing him, Aristarchus’s insights—based on lunar shadowing and the relative positions of the sun and moon—didn’t “take off” until another seventy-two human generations had come and gone. Even Aristarchus’s contemporary and fellow Samos native Epicurus—yes, that Epicurus, who was fond of life’s pleasures—claimed the sun hovered nearby and was just two feet in diameter. Two feet! Early evidence, perhaps, that hedonistic ouzo binges are not compatible with math.8

  Meanwhile, odd celestial events, such as eclipses, along with earthquakes and other scourges, were usually seen as a manifestation of anger from God or the gods. It became our human task to figure out why the deities were so enormously ticked off and to appease them. Moreover, for more than thirty centuries, natural events that either threatened life or were considered capable of doing so—and these included comets, planet conjunctions, eclipses, storms, and epidemics—were regarded as omens. They didn’t just happen, they had meaning. Omen interpretation was a popular activity and, for those with the gift of gab, a lucrative business. There was no word in either Greek or Latin for “volcano”—which illustrates how little importance was paid to the physical event as opposed to the presumed underlying cause, divine fury.

  Meanwhile, to rational Greeks, the issue of what moves and what doesn’t remained secondary to the basic question of why anything should move in the first place. It may have seemed an insoluble problem, but Leucippus, and especially his student Democritus, who was born around 460 BCE, originated and popularized the idea that everything is composed of infinitesimally small moving particles called atoms. Each is colorless and indivisible, they said, and when atoms glom together to form the various objects around us, those objects mobilize as a result of their atoms’ motions.