Dreaming of Death Rays

COMMENT BOOKS & ARTS

The sample, they deduced after PHYSICS many unexpected twists and turns, had probably been found on Russia’s remote, volcanic Kamchatka Peninsula. Steinhardt led an expedition there in Dreaming of death rays 2011 — a wild scavenger hunt search- ing for the stream that the team thought Lasers have long held allure for physics, the military contained the original source. The and science fiction, finds Luke Fleet. group ultimately worked out that the speck came from a meteorite that also contained a second natural quasicrystal, asers first emerged nearly 60 years of the current US dubbed decagonite. ago, but the idea of using powerful president), declared This book is a front-row seat to history beams of heat or light is hardly new. it too speculative. as it is made. For quasicrystal aficionados LIn the third century bc, for instance, Greek The United States like me, it is riveting. For anyone who has scientist Archimedes allegedly used mirrors was hardly alone in reflecting the Sun’s rays to attack Roman its fervour for a death ships off Sicily. Millennia later, ‘death rays’ — ray. Before the Sec- concentrated light or electricity — became ond World War, the a science-fiction trope, from H. G. Wells’s British air ministry 1898 The War of the Worlds to the Star Wars offered a bounty of franchise. Lasers, Death £1,000 (more than Rays, and the As often happens, futurist fiction sparked Long, Strange £60,000 (US$76,000) the real thing. And that’s the story told in Quest for the today) to anyone TRUSTEES OF PRINCETON UNIV. OF PRINCETON TRUSTEES Lasers, Death Rays, and the Long, Strange Ultimate Weapon who could craft and Quest for the Ultimate Weapon. JEFF HECHT demonstrate a ‘ray As the title indicates, Jeff Hecht’s book Prometheus (2019) weapon’ that could is not about the mundane, ubiquitous kill a sheep at 100 lasers of supermarket checkouts and CD metres. (This was ambitious: by the end of players. Hecht, a science writer who has the Second World War, the Japanese mili- covered lasers since the 1970s, instead tary could still only kill rabbits at 30 metres records efforts to adapt the technology for using microwave tubes.) By the 1950s, a military use. In 1934, for instance, inventor new invention was about to focus minds. Nikola Tesla — instrumental in developing The laser, as Hecht makes clear, was a the alternating-current electricity system technology intertwined with politics. The — announced that he had attempted to star figure is physicist Gordon Gould. design a device that would send a ‘death In the late 1950s, Gould explored using beam’ of concentrated particles to detect light to optically ‘pump’ a maser — a Paul Steinhardt with a quasicrystal model. and destroy submarines. As Hecht relates, device emitting microwaves at a specific US government agents looked into the pro- frequency, invented by physicist Charles dreamt of finding a scientific needle in posal after Tesla’s death, but reviewer John Townes in 1953. This was, in essence, the a haystack, it is exhilarating. Steinhardt G. Trump, an electrical engineer (and uncle first conceptualization of a laser, which strikes a balance between mathematical detail and accessibility. He captivates with vivid details about his wonder, frustrations and even a few moments of unleashed ego. We learn about the deep ESVA/AIP/SPL relationships and bold ideas that kept his journey on course. This nail-biting narrative reminds us that the thrill of scientific discovery is not found in a single eureka moment. It is instead marked by determination, team work, optimism and, importantly, luck. Contemplating Julia 89, an aster- oid orbiting the Sun between Mars and Jupiter that could be the source of the fateful meteorite, The Second Kind of Impossible ends as it begins — with the possibility of impossibility. ■

Sharon Glotzer is the John Werner Cahn Distinguished University Professor of Engineering at the University of Michigan in Ann Arbor, and the Anthony C. Lembke Chair of the Department of Chemical Engineering. e-mail: [email protected] Gordon Gould (left, with Ben Senitsky) experimented with microwave lasers in the 1950s.

An artist’s impression of a high-energy laser in use on a US Airforce fighter jet.

works when electrons in a medium (often US president Ronald Reagan is a central lasers. One promising candidate exploits a gas or crystal) absorb energy from light figure in this story. Hecht notes an odd vapours of alkali metals such as potas- or electricity, become ‘excited’ and decay. echo between his years as a Hollywood sium, which allows conversion of almost The result is an intense beam of colli- actor and his tenure in the White House. In all the energy used to excite the electrons, mated, or parallel, rays of electromagnetic 1940, Reagan starred in Murder in the Air without heating problems. Ironically, radiation. as an agent trying to destroy an aeroplane- alkali-metal lasers were an early project Gould’s progress towards the real thing, mounted ray weapon that could disable that the Pentagon left unclassified — so however, was impeded by troubles with engines. In the 1980s, while in office, he Gould could work on it without security patents and politics. In the late 1950s, he announced the Strategic Defense Initiative clearance. NICHOLAS VIOLOA/INFOSCITEX/USAFRL pitched the concept of powerful ray guns to disable actual nuclear missiles. Inspired Hecht’s decades-long immersion in the using lasers to the US defence depart- by some of Teller’s ideas, one proposal was topic gives his narrative an insiders’ edge. ment’s Advanced Research Projects Agency a space-based laser system to disarm mis- In the 1970s, for instance, he worked for (ARPA, the predecessor to today’s DARPA), siles, explored after Reagan’s notorious the magazine Laser Focus. Although this which developed military technologies. The 1983 ‘Star Wars’ speech. (President Don- mainly concentrated on research applica- agency invested heavily, but Gould’s his- ald Trump is not tions — such as using laser light at different tory as a former member of the Commu- the first to explore “As often frequencies to study the properties of atoms nist Party USA caught up with him: ARPA a ‘space force’.) happens, — it inevitably covered stories that would made the project classified, then denied After the end futurist fiction find uses in laser weapons. The cover of him clearance. It was physicist Theodore of the cold war, sparked the real the December 1974 issue featured a mirror Maiman of the Hughes Research Labora- Hecht relates how thing.” that could adjust its shape to change how tories who first demonstrated a laser, in the focus shifted it reflected light; in the 2000s, the US Air Malibu, California, in 1960. Maiman back to laser-based weaponry for use Force deployed the technology for its giant also got the patent and a paper in Nature in the atmosphere. In 2008, the US Air flying laser programme. (T. H. Maiman Nature 187, 493–494; 1960). Force, using a Boeing 747 aeroplane, Lasers, Death Rays, and the Long, Strange Gould, after significant battles, did manage adaptive optics and more than $4.3 billion Quest for the Ultimate Weapon is not an to secure important early patents himself. in funding, fired the first shots of such a easy story to tell, given the vast cast of terrifying system. Despite its success, the scientists, myriad technologies and grim WAR MACHINE programme was discontinued in 2011, purpose. It does, however, capture the Hecht tours the most powerful lasers imagi- with $5 billion already spent. adventures and misadventures of big laser nable. These range from 1960s ‘rocket- Smaller-scale military applications also development from an important perspec- engine’ lasers that emitted light by burning feature, as do solid-state lasers. These use tive for our times. Beyond the intriguing hot gases, to physicist Edward Teller’s 1970s a solid ‘host’: optical fibres with traces of details of tomorrow’s technologies, there idea of weaponizing X-rays emitted from dopants such as rare-earth elements, or lies a pressing question: will future politi- nuclear bombs. The Pentagon kept invest- the interface between two semiconductor cal leaders be more interested in defence ing massively, particularly in lasers that materials. They are so precise that they than attack? ■ could hit airborne targets such as missiles. can slice through communication lines or Getting the laser system itself airborne was disable small drones. Hecht touches, too, Luke Fleet is a senior editor and team the real challenge, however. on the next generation of high-powered leader at Nature in London.