The Scientific Detective: How Luis W. Alvarez Pursued Theory Through Practice

“Successful physics is fundamentally antisocial, successful that it involves showing wherever nan astir illustrious physicists of nan past person been wrong.”

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–Luis W. Alvarez
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On May 31, 1970, nan physicist Luis W. Alvarez took his family connected a section travel to nan San Leandro Rifle Range. He parked his car conscionable extracurricular a fenced wedge of overgrown writer and scrub that covered half an acre of shoreline, wherever a constrictive sliver of San Francisco Bay extended into nan onshore for illustration a pointing finger. It was a pleasant thrust of astir half an hr from his workplace astatine nan Lawrence Radiation Laboratory successful Berkeley, which made it a convenient location for him to dramatically show his mentation astir nan decease of a president.

As Alvarez emerged from nan driver’s seat, nan upwind seemed cleanable for a Sunday excursion. He was fifty-­eight and casually dressed successful a collared garment pinch short sleeves, which would person made him look arsenic astatine location successful an accountant’s agency aliases astatine a console for nan motorboat of a spacecraft. A thin six ft two, he was nary longer nan skilled gymnast of his youth—­most of his workout these days was confined to nan play course—­but he was still an imposing figure, pinch good blond hairsbreadth receding from a precocious forehead and piercing bluish eyes down browline glasses.

Beside him was Janet, his 2nd wife, who was 2 decades younger and smartly attired successful shades, a plaid sunhat, and a sleeveless blouse. In her arms Janet carried Helen, their two-­year-­old daughter, while their son, Donald, who was four, brandished a artifact front and arrow. They stood backmost arsenic Alvarez issued instructions to nan younger colleagues who were mounting up his experiment. Paul Hoch, a bearded postgraduate student from Berkeley, tossed 1 of their targets—­a mini melon—­playfully into nan air. Another cardinal subordinate was Sharon “Buck” Buckingham, a laboratory technician who was besides an enthusiastic cervid hunter.

While a 3rd associate, Don Olson, positioned a camera, nan others prepared nan melons, which were wrapped successful two-­inch fiberglass portion to amended approximate nan qualities of a quality skull. A woody guidelines was group astir 30 yards from nan covered firing position successful nan shooting lane, wherever a marksman named Dewey Machinelli stood pinch a .30-­06 rifle. The first 3 melons would beryllium placed connected nan ground, while different 4 would beryllium balanced aliases suspended connected nan target itself.

As nan others withdrew, Machinelli aimed done his scope astatine nan first melon. Alvarez watched intently to spot really it would respond to nan bullet. Common consciousness dictated that it would beryllium driven distant from nan shooter, but he predicted that it would move successful nan other direction—­toward nan root of nan gunshot. It seemed paradoxical, but if he was right, it would illuminate a important constituent successful nan astir arguable execution investigation successful American history.

Unlike astir of nan amateur detectives who obsessed complete nan assassination of John F. Kennedy, Alvarez had a individual relationship to nan victim. Although his authorities were usually connected nan blimpish side, he had registered arsenic a Democrat successful 1960 retired of enthusiasm for nan move young candidate—­six years his junior—­whom he later described arsenic “very overmuch a leader of mine.”

Alvarez, who met President Kennedy twice, was shattered by nan events of November 22, 1963. He people sympathized pinch nan Warren Commission—­he had served connected akin committees himself—­and accepted its conclusion that Lee Harvey Oswald had acted alone. Doubts would soon originate complete nan lone gunman theory, but Alvarez avoided being drawn into nan statement for different 3 years.

In 1966, connected nan time earlier Thanksgiving, Alvarez listened complete luncheon arsenic his postgraduate students based on astir nan existent screen communicative successful Life magazine, “A Matter of Reasonable Doubt.” It featured nan champion stills ever published of nan location movie taken by eyewitness Abraham Zapruder, which offered nan clearest grounds of nan crime segment successful Dallas. Recognizing it astatine erstwhile arsenic nan benignant of problem that he knew best, Alvarez reviewed nan article astatine home, examining nan pictures pinch emblematic fervor: “I sewage very small slumber that agelong vacation weekend.”

Although Alvarez had nary master inheritance successful forensic analysis, he was assured successful his expertise to extract caller accusation from immoderate of nan astir scrutinized images of each time. For years, he had studied photos from nan hydrogen bubble chamber, nan massively analyzable instrumentality that he had designed to grounds nan tracks of subatomic particles. Now he redirected those skills toward nan Zapruder film, uncovering ocular grounds successful nan stills to find nan timing of nan shots, nan framework rate, and nan velocity of nan limousine.

It was an ingenious portion of detective work, but not each mobility could beryllium resolved solely pinch photographs. Hoch, his postgraduate student, was portion of an informal web of Warren Commission critics. When Alvarez later asked what he thought was nan champion grounds for a conspiracy, Hoch said, “The caput snap.” At nan fatal 3rd shot, Kennedy’s caput moved backmost and to nan left, which seemed to bespeak an effect from nan front. This backward—­or retrograde—­movement was inconsistent pinch Oswald’s position to nan rear successful nan Texas School Book Depository, pointing alternatively to a shooter connected nan infamous grassy knoll.

If nan changeable came from nan back, a lone gunman was still possible; if it came from nan front, location must person been a 2nd shooter—­and, by definition, a conspiracy. Anyone who believed that Oswald had acted unsocial needed to relationship for nan mobility of nan president’s head. After Alvarez speculated that Kennedy had simply fallen backward erstwhile his cervix muscles went limp, Hoch handed him nan book Six Seconds successful Dallas by Josiah Thompson, which made an exceptionally beardown lawsuit for a conspiracy based connected nan beingness evidence.

Although he rejected nan book’s conclusions, Alvarez respected its approach. In February 1969, he flew to a gathering of nan American Physical Society successful St. Louis, which he was attending for nan first clip since winning nan Nobel Prize nan twelvemonth before. As he publication Thompson’s book connected nan plane, he was impressed by its diagrams, which led him to work together that nan conspiracy theorists were correct astir 1 thing: “The president’s caput did not autumn but was driven backmost by immoderate existent force.”

In his edifice suite, he worked retired a solution connected a expanse of scrap paper. “Since I knew much physics than nan [conspiracy] buffs,” Alvarez said, “it didn’t return maine long.” The answer, he felt, was amazingly simple, erstwhile you corrected for a mistaken assumption. Most observers treated nan effect arsenic though it progressive only 2 bodies—­the slug and nan skull—­in an inelastic collision, successful which astir of nan kinetic power was dissipated arsenic heat. Alvarez realized that it mightiness activity otherwise successful practice, mostly because of a 3rd facet that had to beryllium taken into account.

Rather than transferring each its momentum to nan head, a slug would suffer astir of its power successful a burst of debris, arsenic nan skull’s contents exploded outward. If nan spray of encephalon matter seen successful nan Zapruder movie was moving successful nan aforesaid guidance arsenic nan gunshot, it could transportation greater momentum than nan slug itself, requiring a mobility successful nan other direction. Counterintuitively, nan caput would beryllium thrust back, for illustration a rocket ejecting its propellant. The pitchy effect, Alvarez concluded, could explicate nan backward threat without a changeable from nan front.

When Alvarez returned to Berkeley, he shared his activity pinch his colleagues, 1 of whom recalled that nan consequence was “tepid.” His calculations were elegant, but location was nary guarantee that they correctly described a arena successful nan existent world. Hoch soon convinced him that he wouldn’t seduce nan skeptics “unless we could show nan retrograde recoil connected a firing scope utilizing a reasonable facsimile of a quality caput arsenic a target.”

In response, Alvarez organized nan bid of tests that ended pinch his sojourn to nan San Leandro shooting scope successful May 1970. As he invited his family to watch, nan rifleman changeable 7 melons. Six rocketed backmost successful nan guidance of nan shooter, precisely arsenic he had predicted. When Alvarez publicized his findings, they seemed for illustration a technological vindication of nan Warren Commission’s conclusions.

What almost nary 1 knew was that nan published results—­while accurate—­were only portion of nan story. By cautiously readying nan last demonstration, Alvarez obtained nan result that he wanted, and he ne'er mentioned a brace of earlier attempts that were overmuch little definitive. As he later wrote successful different context, “Many group deliberation that solving a technological puzzle is an workout successful logic that could beryllium carried retired arsenic good by a computer. To nan contrary, a technological detective’s main stock-­in-­trade is his expertise to determine which grounds to ignore.”

*

At nan highest of his fame, Alvarez was 1 of nan world’s astir salient scientists—­a Nobel laureate whose profession ranged from Hiroshima to nan extinction of nan dinosaurs. Today, however, he mightiness champion beryllium known for a short segment successful Christopher Nolan’s Oppenheimer. Early successful nan movie, nan physicist J. Robert Oppenheimer is strolling down a sidewalk successful Berkeley pinch his lover, Jean Tatlock, erstwhile he sees a acquainted fig unreserved retired of a barber shop. Leaving Tatlock behind, Oppenheimer runs aft his colleague, calling his name: “Alvarez?”

At nan lab, Alvarez excitedly shows Oppenheimer and Ernest Lawrence, his mentor, a newspaper article announcing that 2 German chemists person divided nan atom. As Alvarez dashes retired of nan room, hoping to reproduce nan experiment, Oppenheimer heads for nan blackboard, which he fills pinch equations to show that nan fission guidance is impossible. After seeing nan proof, Lawrence advises him to spell adjacent door, saying gleefully, “Alvarez did it.”

In nan adjacent shot, Oppenheimer watches arsenic Alvarez shows him a bid of spiking pulses connected an oscilloscope, indicating that fission is so taking place. Understanding its value astatine once, Oppenheimer confers pinch Lawrence, who agrees that everyone who sees it will beryllium reasoning nan aforesaid thing. Glancing uncertainly betwixt nan 2 different men, Alvarez asks, “What are we each thinking?” Oppenheimer responds dryly, “A bomb, Alvarez. A bomb.”

Aside from a fewer insignificant departures from nan facts, nan segment is remarkably accurate, moreover if nan character Alex Wolff bears minimal resemblance to nan existent Alvarez, who was tall, blond, and blue-­eyed. Confusion complete his inheritance would persist aft his death, but nan truth, arsenic nan clever clever Jesús Rubén Martínez wrote, was straightforward enough: “Alvarez was a achromatic man pinch a Hispanic name.”

After his little quality successful nan film, Alvarez vanishes from it entirely, leaving nan casual spectator without immoderate hint of nan stunning profession that would follow. A 1957 floor plan successful Time mag called Alvarez nan field’s “prize wild-­idea man,” while Glenn Seaborg, a chap Nobel winner, hailed him arsenic “the astir imaginative and versatile intelligence I person ever known.” Richard Muller, his longtime protégé, went further: “Luie Alvarez, I think, if you took a study of physicists, could astir apt triumph nan astir votes for being nan top experimental physicist of nan twentieth century.”

Perhaps nan astir revealing tribute of each came from Richard Feynman. In 1986, while serving connected nan committee to analyse nan Challenger disaster, Feynman conceived of a celebrated demonstration—­involving a portion of rubber and a solid of crystal water—­to show that nan O-­ring seals successful nan abstraction shuttle’s rockets became unreliable astatine debased temperatures. At first, he was hesitant to execute it successful public. “But past I deliberation of Luis Alvarez, nan physicist,” Feynman recalled. “He’s a feline I respect for his gutsiness and consciousness of humor, and I think, ‘If Alvarez was connected this commission, he would do it, and that’s bully capable for me.’ ”

Charismatic, physically agile, and daring, Alvarez was 1 of nan past representatives of an era that could still spot physics arsenic a heroic enterprise. He sought caller challenges successful nan astir fascinating places imaginable, from nan Great Pyramids to nan Cretaceous wide extinction, which became his azygous top triumph. Reasoning brilliantly from nan evidence, he concluded that nan dinosaurs were doomed by an effect from space, igniting a furious statement that consumed nan past years of his life.

His communicative is inseparable from nan emergence of experimental physics, which he ushered into its modern age. Even much than Oppenheimer aliases Lawrence, Alvarez offers nan champion imaginable preamble to its devices and secrets. As an experimenter, not a theorist, he thought pinch analogies, alternatively than mathematics, making his activity highly accessible. While scientists successful nan laboratory seldom execute nan fame of their theoretical counterparts, nan experimentalists, arsenic Alvarez noted, person nan past connection connected whether a mentation is valid: “The only correct measurement to find retired is to entreaty to experiment.”

Alvarez has been described arsenic a technological Indiana Jones, but his estimation arsenic a maverick was built connected a instauration of patience and discipline. “In nan fields of observation,” Louis Pasteur said, “chance favors only nan prepared mind.” To return advantage of luck, Alvarez had to stay perpetually astatine nan ready. He positioned himself to use from happy accidents, and galore of his discoveries resulted from taking nan problem to understand a astonishing result.

Physics was afloat of these opportunities, but only for those who could admit them. Alvarez had a “killer instinct” for noticing what others had overlooked—­what 1 subordinate called “a benignant of brilliant for moving astir and trying to spot if there’s 1 spot that’s an evident bottleneck”—­and refused to time off it to chance. Every week, Muller said, “Luie group speech 2 hours to deliberation astir what he had learned, and if they could use to immoderate of nan unsolved problems that he knew successful physics, technology, aliases world affairs.” As Alvarez put it, “If personification thinks of a key, I tin fresh it into something. I person successful my mind dozens of experiments which request 1 missing piece.”

One workfellow marveled that Alvarez could make capable ideas for a 100 people: “That’s what they person him location for.” Another commented, “Although Luie mightiness person 1 100 ideas each day, 50 were astir apt useless, different twenty-­five excessively difficult to do, and among nan remaining twenty-­five 1 aliases 2 would beryllium worthy a Nobel Prize.” Muller noted that it was a deliberate strategy: “Luie had taught maine that astir clever ideas are proven to beryllium incorrect wrong a fewer days. If you negociate to person 1 bully thought each week, past you tin expect to find 1 each fewer months that is really worthy pursuing.”

And nary of it would person mattered if he had lacked nan method expertise to recognize his hunches. After mastering nan arts of nan machinist and glassblower, he applied himself pinch adjacent diligence to accelerator physics. He besides molded himself into a relentless leader of teams, which successful his hands became different tool. As nan historiographer Peter Galison has written, Alvarez did for peacetime subject what Andy Warhol did for art, turning it from a solitary pursuit into a factory. By combining nan bubble enclosure pinch nan computer, he created a instrumentality for generating serendipity.

A accepted intelligence mightiness person been contented to support mining this rich | vein of material, but successful an unprecedented alteration of heart, Alvarez turned his backmost connected it. When nan process became routine, he pivoted to problems that were unsolvable by computational powerfulness alone, arsenic if to show nan worth of individual insight. Late successful life, he became thing little than nan world’s foremost technological detective, which was a calling that he could prosecute connected his ain terms.

As a result, Alvarez was 1 of nan fewer experimental physicists who excelled astatine each stage. At a clip erstwhile technological knowledge was expanding rapidly, he resisted specialization, pinch what Muller called “a knack for learning conscionable nan correct magnitude astir everything.” His persistence was powered by an different expertise to unrecorded pinch uncertainty. He was realistic capable to for illustration problems pinch a precocious imaginable reward, but he still relished nan praise of a workfellow who said, “You person a greater tolerance for consequence than anyone I’ve ever known.”

Alvarez knew that a broad relationship of his life would double arsenic a benignant of manual connected really to win successful physics, and he labored complete a book that told his broadside of nan story. Once, astatine a meal party, he fell into speech pinch nan woman of his rival Emilio Segrè, who was preparing a memoir of his own. When Rosa Segrè asked if he spent a batch of clip reference aged letters, Alvarez responded, “Oh, no, I conscionable constitute down what I remember.”

In 1987, nan twelvemonth earlier he died, his autobiography was published by Basic Books. Alvarez: Adventures of a Physicist was an engaging circuit of nan highlights of his career, but it was arsenic notable for its omissions. After his death, nan astrophysicist George Greenstein mentioned him to a colleague, who replied, “Luis Alvarez—­wasn’t he that boy of a bitch retired astatine Berkeley?” And erstwhile Greenstein asked if Alvarez had really been “a boy of a bitch,” nan consequence said volumes: “Well, I ne'er knew him personally, but I understand that he was.”

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Reprinted from Collisions: A Physicist’s Journey from Hiroshima to the Death of nan Dinosaurs by Alec Nevala-Lee. Copyright © 2025 by Alec Nevala-Lee. Used pinch support of nan publisher, W. W. Norton & Company, Inc. All authorities reserved.