American Scientist

A reprint from

American Scientist

the magazine of Sigma Xi, The Scientific Research Society

This reprint is provided for personal and noncommercial use. For any other use, please send a request to Permissions, American Scientist, P.O. Box 13975, Research Triangle Park, NC, 27709, U.S.A., or by electronic mail to [email protected]. ©Sigma Xi, The Scientific Research Society and other rightsholders

Perspective

Outpost on the Edge As the founding site of the National Radio Astronomy Observatory falls into decline, we are losing much more than a once-great research facility. Tony Rothman

I

t was not a place you’d generally find yourself in by accident. Out of Staunton, Virginia, you followed Route 250 over the Alleghenies. Up, down, around, up again, down once more. After the seventh mountain—eighth?—you’d reach Deer Creek Valley and turn south onto Route 28. By that time the car radio was dead. If evening approached, you might be welcomed by a spectacular sunset: crimson, purple, and gold braiding the open vault. More likely, you’d arrive in daylight. Then, towards Green Bank, past the road signs riddled with bullet holes, a line of great dishes running down the valley suddenly rose to greet you. You caught your breath and knew you had finally arrived at the National Radio Astronomy Observatory. This is the NRAO I still picture in my mind’s eye, the extraordinary vista that greeted me as a summer research student when I first arrived in 1974. No matter that my imagined view may not have been quite possible from Route 28. No matter that the lonely flapping of the rope on the lab building’s flagpole added to a sense of remoteness so profound that one often wanted to flee over the mountains. No, what matters is that the first sight of those great telescopes instilled in me a wonder that across the span of four decades has not wholly vanished. In 1974, NRAO was scarcely 20 years old. Created in 1956 as the National Science Foundation’s first large-scale endeavor, its ambitious scope reflected the post-war science boom. This rural outpost was the largest observatory in Tony Rothman has taught physics at Princeton and Harvard. His latest book is Firebird (Wildside Press, 2015), a suspense novel set against a race for nuclear fusion. On Twitter: @TonyRothman1 24

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the United States, and perhaps the most secluded. Searching for a site in the 1950s, Associated Universities Incorporated, which runs NRAO, laid down strict criteria: surrounded by as many mountains as possible, free of high-tension towers, far from commercial airline routes, not prone to severe storms, and free—insofar as possible—of people. In 1958 the Federal Communications Commission established the National Radio Quiet Zone around the new observatory to protect it from interference. Today, NRAO runs most of the country’s radio astronomical facilities and is the American partner in the new Atacama Large Millimeter Array in Chile, a powerful new facility for studying star formation and cosmic origins. But even as ALMA was taking shape, NRAO’s original Green Bank site stepped into an uncertain future. Three years ago a National Science Foundation panel, citing duplication of capabilities with newer facilities, recommended that Green Bank’s flagship radio dish be defunded by 2017. The observatory’s original three-element interferometer was decommissioned in 2000, and the 140-foot telescope (yes, in those days the telescopes were measured in feet) is now rented to the Russians. With NSF funds evaporating, West Virginia University has offered $1 million towards operation of the Green Bank Telescope and NRAO finds itself, hat in hand, begging for anyone at all to take over the interferometer and turning to China for collaborations. “Can Do” If loneliness was the first thing that hit you upon arrival, the remnants of a certain funky do-it-yourself attitude hit you soon thereafter. Back when I arrived, the founders of radio astron-

omy still walked among us. Grote Reber, who’d built the first parabolic dish radio telescope in his backyard, was the subject of more than one evening anecdote. Apparently fed up with the increasing size of science, he had fled to Tasmania and was stringing cables between mountain peaks to measure ultra-low frequency radio signals. In a trailer on the grounds one of the engineers tested cables for the Very Large Array, the 27-dish facility later built near Socorro, New Mexico; and although Frank Drake’s Project Ozma, the world’s first search for extraterrestrial intelligence, came up empty, it did lead to state-of-the-art receivers. The most visible of NRAO’s telescopes, the old 300-foot, was a perfect example of that can-do mindset. Arriving on a weekend and finding few signs of life, I walked out to the dish. The wind whistling through the mesh, the metallic creaking of the enormous structure, and the electronic bleeps descending from above intensified the sensation that I had attained the borderland between Earth and space. As I soon learned, the behemoth had been thrown together a decade earlier by my assigned advisor, John Findlay. Findlay was a crusty Englishman who spoke with an Oxbridge accent and smoothed down his hair with shoe polish. One of the observatory’s original two scientists, he’d participated in the development of English radar during World War II and was recruited by NRAO in 1956 to create the electronics division. He strode the grounds in shorts and a white shirt and was, so I heard, prone to outbursts of extreme anger. He addressed me as “Young Rothman” and we got along fine. Though little known outside of scientific circles, Findlay was instrumen-

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tal in creating hugely visible projects. He had chaired the Lunar and Planetary Missions Board, which from 1967 to 1971 advised NASA on all its probes to the Moon and planets. The Board met regularly at NRAO and gave birth to the Viking Mars Mission at a meeting in the lab-building basement. The 300-foot was another of Findlay’s children. Soon after its founding, NRAO established plans to build a 140-foot radio telescope. The steering committee decided that the telescope’s dish should sit on the world’s largest equatorial mount, a choice that proved nearly fatal. Fabrication of the mount, which required that the telescope’s entire weight rest on a 400-ton ball bearing, turned into a nightmare. Construction began in 1958, but within a few years it was unclear whether the telescope could be completed. Fed up with the quagmire, Findlay conceived a “quick and dirty” telescope that would allow American radio astronomy to get up and running as quickly as possible (maybe with a little help from David Heeschen, one of NRAO’s other originals, and Otto Struve, the director). The NSF approved the construction contract within four days. First observations took place in September, 1962, less than two years after Findlay had begun design studies. The main cost-saving device was that the 300foot was a transit instrument, capable of being tilted only north and south. As Findlay put it, they had built the www.americanscientist.org

The National Radio Astronomy Observatory facility in Green Bank lives in its own isolated world in the mountains of West Virginia. The modern 100-meter dish is at back left.

world’s largest movable telescope “for the price of sugar”: 68 cents per pound, $850,000 total, compared to $13.5 million for the 140-foot when it came online in 1965, five years behind schedule. The 300-foot’s life ended one night in 1988 when it catastrophically collapsed. The media cried, “Design failure!” failing to understand what Findlay had told me: “We expected it to last five years.” It lasted a quarter of a century and proved to be NRAO’s greatest bargain. The 100-meter Green Bank Telescope that replaced it was far more advanced, but cost $95 million. The 300-foot’s most famous discovery was the Crab Nebula pulsar, which clinched the interpretation that pulsars are rotating neutron stars created in supernova explosions. The telescope also gathered data on radio emission from neutral hydrogen, which enabled the mapping of the spiral structure of our galaxy. When the 140-foot was completed, it ultimately proved itself one of the world’s most productive astronomical instruments. Among its discoveries were interstellar clouds of formaldehyde and other organic molecules, which may be essential for the evolution of life. It also became a crucial link in Very Long Baseline Interferometry, in which two or more radio dishes are linked to create the equivalent of a single telescope with

the resolving power of a dish as wide as a continent or as Earth itself. NRAO scientists were instrumental in developing this technique. In 1974, Green Bank boasted an interferometer consisting of three 85-foot dishes that could be spread out across nearly a mile. With a fourth portable dish, the baseline could be extended to 20 miles; NRAO astronomers employing that configuration discovered Sagittarius A*, now known to be a supermassive black hole at the Milky Way’s center. Journey from Small to Big Traditional radio interferometers, with a few widely scattered dishes, have a limited collecting area and are restricted to observing comparatively bright sources; fainter objects require single, large telescopes. But with the declining cost of electronics it has become cheaper to construct arrays like ALMA from many small dishes than to build a single large one. A few years before I arrived at NRAO, Green Bank received approval for the Very Large Array (VLA) a set of 27 mobile dishes placed along 36 kilometers of track in New Mexico. NRAO staffers were scratching their heads, trying to write control software to run on computers that did not yet exist. They succeeded, setting the stage for more complicated arrays—and for their own demise.


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My duties at NRAO that first summer in 1974 were on a decidedly smaller scale: the care and feeding of John Findlay’s “Little Big Horn,” a rectangular antenna 125 feet long that pointed skyward from a ravine. Using his horn, Findlay measured the absolute luminosity of Cassiopeia A, the remnant of a supernova that exploded about 300 years ago. Cas A then became a standard candle by which to calibrate other radio sources. With the Little Big Horn, Findlay had also apparently stumbled on the cosmic microwave background radiation a year before Arno Penzias and Robert Wilson, whose detection provided clinching evidence for the Big Bang. Findlay showed me his data but hadn’t recognized their implications. For me, the Little Big Horn recently accrued a more symbolic meaning. Returning to Green Bank last year, I discovered it so forgotten that many NRAO personnel were unaware of its existence. Overgrowing shrub and brush rendered it invisible to roaming deer, and trees had broken through the wooden steps to the ruined control hut. As a summer student, I was also responsible for a week’s worth of tourist lectures, in which we tried to explain to the visitors what we did at NRAO. Although occasionally displaying an interest in science, more often visitors wanted to know whether we had detected any UFOs. (No.) Mostly, they wanted to know whether our work was classified. When I replied absolutely not, the typical response was, “Then you aren’t doing the country any good.” The question was more

à propos than they realized. In the 1950s at nearby Sugar Grove, the NSA established a listening post and attempted a 600-foot radio dish--the other, unspoken reason for the National Radio Quiet Zone. The Big Dish was intended to intercept Soviet communications bounced off the moon, but instead became one of the great scientific-military boondoggles. As a benefit, though, even today the Radio Quiet Zone makes cellphone usage virtually impossible. During my first summer, Findlay gave me another task that proved extremely eventful for me. He wanted to create a rover that would roll over radio dishes to measure their surface accuracy, and asked me to provide a mathematical framework for his scheme. I spent a day considering the problem and figured out generally what needed to be done, but before I had finalized an answer, Findlay reported that “Sebastian had seen it at once.” Sebastian von Hoerner, who became my official advisor for my second summer at the observatory, embodied the bootstrapping character emblematic of post-war science. Named after Sebastian Bach, tall and trim, sporting thin and silvering hair, he hailed from an aristocratic Silesian family. He’d been drafted into the German army at the outset of World War II, cheated to complete his undergraduate education on furloughs, lost an eye on the Russian front, survived the Dresden fire-bombings, and finally received a PhD in astrophysics at Göttingen University in the early 1950s. His father was killed in a Soviet concentration

Left: The 300-foot dish at Green Bank used a simple single-axis mount and mesh reflector to save money. Right: “Little Big Horn” antenna, 26

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camp after the War and his mother was released after six or eight years. Sebastian transmuted his hard experiences into a generous, life-affirming spirit that I have rarely encountered and never seen surpassed. Full of OldWorld mottos—“If you ask a stupid question, you may feel stupid. If you don’t ask a stupid question, you remain stupid”—his well-known advocacy of the search for extraterrestrial life was merely one manifestation of an unfettered curiosity that encompassed everything from universal music to the design of human backs. But Sebastian von Hoerner made his main contribution to radio astronomy in telescope design. As they move, giant dishes deform under their own weight, causing the image to blur. Sebastian wondered whether a telescope could be designed to deform from one paraboloid to another as it is tilted. If so, you’d simply have to nudge the receiver from the old focus to the new one, and the image would remain sharp. In answering the question affirmatively, he created the homologous, or shape-preserving, telescope now used in most modern radio dishes. Sebastian’s approach, in telescope design as in all else, lifted engineering into the realm of art, but above all I remember a man who never dismissed an idea out of hand. A man who, as we felled trees in the woods or listened to gypsy music at his home, followed any thought just to see where it led. A man who, despite the fact that his father had been murdered by the Soviets, encouraged me to pursue my Russian studies because I could “talk to people

built in 1959, helped establish the cosmic distance scale but is now abandoned. All photos on this spread are courtesy of NRAO/AUI/NSF..


Dedication ceremony for NRAO included John Findlay (seated) and David Heeschen (second from right), who aided him in creating the 300-foot dish. Behind them is a model of the 140-foot.

Sebastian von Hoerner was a pioneer in radio telescope design, as well as in SETI research.

on the street.” He was perhaps the most inspiring person I have ever met.

gressmen. Defense and dual-use projects, such as Sugar Grove’s Big Dish, are notoriously hard to kill. A dash of socialism may help. We routinely credit Steve Job’s genius for the smart phone, forgetting that the half-dozen crucial technologies it embodies were developed by the government or at universities with federal money. Our agencies, and the scientists themselves, ought to take the cue and plan not only for the next device but for the death of the present one. Funds should be allocated to the repurposing of facilities: to turn an observatory into an educational institution, say, or its staff into an administrative structure for a new project. Room should be provided for non-party-line projects. Points should be awarded for the small and the cheap. Above all, science should be kept human. I wish NRAO well. I’d rather it not become a necropolis of mute instruments, inhabited by tour guides and visitors alone. But if it must fade away as a place of research, I fervently wish that anyone who gazes upon its great telescopes understands they were built by men of vision who devoted their lives to comprehending the universe. Von Hoerner remarked that the role of scientists is to provide a “background” to civilization. I’d like to believe that even as the names of people like Findlay and von Hoerner recede into the background, their lessons will not be lost.

Essential or Obsolete? Or Both? John Findlay and Sebastian von Hoerner both passed away long ago, as by now have most of NRAO’s originals. Plans to defund the 100-meter Green Bank Telescope have brought the foreseeable protests from astronomers. Realistically, however, with the profusion of international collaborations worldwide, the utility of national laboratories may be approaching an end. As NRAO scientists know—having built the VLA and helped create ALMA—science continually regenerates itself. Moreover, America cannot retain the lead in each and every endeavor. In astronomy, bigger is almost always better, and rarely cheaper. With state-of-the-art interferometric arrays like ALMA there is no obvious, compelling need for Green Bank’s old interferometer. It is easy to visualize a world cemetery of projects, each telescope transforming into a tombstone as its successor comes online. Such a landscape, with the concomitant disruption of careers, may be inevitable in an era of accelerating technology. For me, the disappearance of places like Green Bank is a sad consequence of the increasing scales and budgets of science. Last year I remarked to a Russian colleague that few younger physicists seem interested in talking about www.americanscientist.org

actual physics. He replied, “It’s like that everywhere.” Everyone I know who participates in a vast endeavor such as the Large Hadron Collider feels very much a cog in a machine. The days when one could discuss fundamental, useless, and—more to the point—non-party-line questions with the likes of von Hoerner have largely passed in favor of urgent conference calls and more urgent grant deadlines. Science progresses and the new instruments will make great discoveries, but it is difficult to believe that global, virtual collaborations will nucleate the unfettered, sometimes quirky atmosphere of NRAO or provide lifealtering mentors for young whippersnappers. Twenty years ago, when the Superconducting Supercollider was dying, physicist Steven Weinberg remarked to me that the social contract, in which the country provided for fundamental research in return for some of it proving useful, had broken down. The situation has only worsened since. Ultimately, the country must decide at what level fundamental science is worth supporting. The American system of funding is crippled by election cycles occurring on a far shorter time scale than the projects it creates, and many worthy projects have already been interred. The most reliable way to save the Green Bank Telescope would be to turn it over to the NSA, which would undoubtedly suit many Con-


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