The Glenn L. Martin Company (which later became known as Lockheed Martin) set up the Research Institute for Advanced Studies. The institute would explore new ideas in theoretical physics with a special emphasis on unpicking gravity and pursuing gravity propulsion, hiring physicists and relativists to help them pursue their futuristic goal. The US Air Force made a more sober and less outrageous investment in the Aeronautical Research Laboratory, based at the Wright-Patterson Air Force Base in Dayton, Ohio. The ARL also housed a group of bona fide relativists, but they conducted fundamental research in gravity and unified theories. There was no mention of antigravity in their remit, and for a while the research group at ARL was a proper general relativity research center that rivaled the few other groups scattered around the world. The air force also pumped money into other groups that were conducting general relativity research. Few scientists took antigravity efforts seriously, and researchers avoided making any ludicrous predictions, but they happily accepted the money thrown at them to focus on esoteric ideas about the foundations of reality.
In the midst of this euphoria, Bryce DeWitt’s approach to Babson’s contest was certainly a strange way to win an essay competition; he attacked the sponsors. In the essay he submitted to the Gravity Research Foundation in 1953, DeWitt brazenly dismissed Babson’s ambitious aims to develop “grossly practical things such as gravity reflectors or insulators or magic alloys which can change gravity into heat.” He invoked Einstein’s theory of spacetime to explain why “any frontal attack on the problem of harnessing the power of gravity along the above lines is a waste of time. . . . One may safely pronounce all gravity-power schemes impossible.” DeWitt slammed the cranks, and he won.
DeWitt’s essay was definitely different from those of the previous contestants. It was proper science, firmly stepping away from speculation and talking about the real scientific issues that needed to be faced in gravity research. It was a hard task, and, as he said, “gravitation has received relatively little attention during the last three decades.” It was “peculiarly difficult,” involved “recondite mathematics,” and the “fundamental equations are almost hopeless of solution.” Indeed, “the phenomenon of gravitation is poorly understood even by the best of minds.”
Far from insulted, Roger Babson was intrigued by his competition’s first real contender. Here was someone serious, a proper scientist who could make his competition reputable. And indeed, DeWitt’s essay added legitimacy to Babson’s competition, for in the years that followed the caliber of the contestants went up dramatically. In fact, over the following decades many of the physicists who would play a crucial role in the resurgence of general relativity would end up winning prizes from the Gravity Research Foundation. Moreover, the essays became almost exclusively about gravity, and antigravity was forgotten. DeWitt would later say that winning that competition was “the quickest $1000 I ever earned,” but, having taken part in the competition, DeWitt was to benefit much, much more than he had imagined.
Roger Babson had a friend, Agnew Bahnson, who was also fascinated by gravity. Bahnson had made his fortune selling industrial air-conditioning units. Like Babson, he wanted to fund research in gravity. He just wasn’t sure how. Babson showed Bahnson DeWitt’s winning essay. Here was the man to help him set up something serious, a proper, respectable institute where thinkers would be allowed to follow their interests. As Bahnson wrote in one of his inaugural brochures for the newly created Institute of Field Physics, or IOFP for short: “In the minds of the public the subject of gravity is often associated with fantastic possibilities. From the standpoint of the institute no specific practical results of the studies can be foreseen at this time.” There would be no antigravity machines, no gravitational propulsion. Bahnson could satisfy his personal fantasies about gravity another way, by writing science fiction, and leave real gravity to the scientists.
Bahnson turned to John Wheeler for advice on how to proceed with his institute. Wheeler had earned a formidable reputation in Washington for his work on nuclear weapons and more generally as a senior physicist who was willing support the government in all matters related to defense. He had followed DeWitt’s career at a distance and quietly supported the idea that Bryce and Cécile should be invited to be the first researchers at the new institute, based in Chapel Hill, North Carolina.
The institute may have started as a vanity project, but with Wheeler’s backing and the DeWitts as the first hires, it was taken seriously by scientists from all across the country, with letters of support from many of the éminences grises applauding a place where pure research could be undertaken, unfettered by the demands of industry, the army, or the new atomic age. At the core of the new institute would be gravity.
The DeWitts’ January 1957 meeting, titled “The Role of Gravitation in Physics,” was intended to inaugurate the new institute. It also inaugurated a new era. The group of attendees was younger and less well known, but they included some of the new leaders in general relativity. They all converged on Chapel Hill for a few days to take Einstein’s theory apart. Agnew Bahnson and the US Air Force funded it, and the air force even flew some of the participants over to the newly founded Institute of Field Physics.
Not only relativists made the trip to Chapel Hill. John Wheeler’s ex-student Richard Feynman, who had completely overhauled quantum physics and proposed a new way of quantizing nature, decided to attend. A man from the quantum world, he was intrigued by what was going on in general relativity. Feynman later recalled arriving at the airport in Chapel Hill without knowing where to go. Once in a cab, he realized that the driver hadn’t heard of the meeting—why would he have? Feynman turned to the driver and said, “The main meeting began yesterday, so there were a whole lot of guys going to the meeting who must have come through here yesterday. Let me describe them to you: They would have their heads kind of in the air, and they would be talking to each other, not paying attention to where they were going, saying things to each other, like ‘gee-mu-nu. gee-mu-nu.’” Gee-mu-nu (written gμν) is the mathematical symbol for the metric that encodes the geometry of spacetime. The driver knew where to go.
It was apparent to everyone at the meeting that something had to be done to pull the general theory of relativity out of the backwater where it had been languishing for the past three decades. To Richard Feynman, it was obvious why general relativity had been neglected: “There exists . . . one serious difficulty, and that is the lack of experiments. Furthermore, we are not going to get any experiments, so we have to take the viewpoint of how to deal with the problems where no experiments are available.” Without experiments, the field could not progress, but Feynman insisted they had to press on. General relativity was difficult but not that difficult and, as he put it, “the best viewpoint is to pretend that there are experiments and calculate. In this field we are not pushed by experiments but pulled by imagination.”
Feynman echoed the general feeling in the meeting at Chapel Hill, which was full of a new generation of relativists who were about to graduate or had just graduated with new ideas, ready for a fight. As the meeting unfolded, outlandish ideas competed against sober pronouncements by the older pundits. The daily sessions were riven with debate and arguments. When Thomas Gold presented an update on his theory of the steady-state universe, DeWitt chipped away at its key premise—Hoyle’s creation field—questioning the mechanism by which energy conservation would be violated. When someone played up the need for a theory that unified gravity and electromagnetism along the lines that Einstein had spent decades trying to construct, Feynman was unforgiving. Why should electromagnetism be the only force that needs to be unified with gravity? What about everything else, all the other forces in nature? DeWitt and Wheeler’s obsession, how general relativity could be combined with quantum mechanics, was aired and discussed in its various forms and guises. And could spacetime ripple with gravitational waves like the surface of a lake, just like electromagnetic waves in Maxwell’s theory? The participants fought it out in the
lively discussion sessions.
John Wheeler turned up with his grand plan to revolutionize physics through relativity and with his cohort of students and postdocs presented their new ideas. They pushed relativity even further than before, to the point where it seemed like a joke. On the menu was “electromagnetism without electromagnetism” and “charge without charge,” as well as “spin without spin” and “elementary particles without elementary particles.” Throughout the meeting, the Wheeler clan took center stage, throwing ideas into the crowd to be thoughtfully considered or batted away. John Wheeler was in his element.
At an even more basic level, the relativists at Chapel Hill asked themselves if it was even possible to make realistic predictions with Einstein’s theory. If a theory is going to have any cachet, it must be predictive. So, for example, electromagnetism is supremely successful at predicting just about everything that pertains to light, electricity, and magnetism. But, while Schwarzschild, Friedmann, Lemaître, and Oppenheimer had all been able to make predictions, they had restricted themselves to highly simplified, idealized systems. And it wasn’t clear how to go beyond those simplifications. Indeed, the participants of the Chapel Hill conference asked themselves, Was it even possible to generally solve the Einstein field equations properly and make real bona fide predictions about how spacetime evolves? It seemed that the hideously entangled nature of general relativity makes just choosing the initial conditions, let alone the evolution, almost impossible. Attempting to solve the equations on a computer was an even more daunting task.
The meeting was an exciting forum for relativity’s new adherents, bursting with creativity and invigorated by John Wheeler’s inventiveness and Feynman’s imagination. But the theory of spacetime was still stuck. All the mathematical ingenuity, the proposals for unification, the debates about gravitational waves, and Wheeler’s wormholes, geons, and spacetime foam were useless if they couldn’t be pinned to the real world.
It had been almost forty years since Eddington’s eclipse measurement, the first big test of Einstein’s theory. Almost thirty years had passed since Hubble’s measurement of the expansion of the universe. At the Chapel Hill meeting there were no new measurements, nothing to further confirm or even unsettle Einstein’s theory. One of Wheeler’s Princeton colleagues, Robert Dicke, summed up the situation in a talk on “The Experimental Basis of Einstein’s Theory” when he said, “Relativity seems almost to be a purely mathematical formalism, bearing little relation to phenomena observed in the laboratory.” The answer, as it turned out, was to be found not in the laboratory but in the stars.
In 1963, the Dutch astronomer Maarten Schmidt had the run of a telescope named after George Ellery Hale, the patron of the Palomar observatories. On his mind was one of the sources in the 3C Catalogue of radio astronomers Martin Ryle and Bernard Lovell. While Wheeler and his crew were reenergizing general relativity, radio astronomers were taking a closer look at the radio sources in their surveys. As with any other stargazers, their goal was to figure out what the radio sources actually were. To do so, they needed to find more of them. And they needed to look at them more carefully to figure out what was actually emitting the radio waves.
Over more than a decade, deploying the ingenuity that had helped them develop radar, Ryle and Lovell increased the precision of their measurements by orders of magnitude, enabling them to pinpoint the radio sources in the sky exactly enough for astronomers to point their ordinary telescopes at them and figure out what they were. Ryle’s 3C Catalogue of radio sources included hundreds of sources with precise locations.
Lovell’s group looked at Cygnus A, one of the radio sources that Grote Reber had identified above the cosmic static emanating from the galaxy and dubbed 3C405 in Ryle’s catalogue. Cygnus A turned out to be a strange object, consisting of two lobelike blobs of radio waves, each one almost rectangular in shape. They were gigantic structures, each one hundreds of light-years across, and seemed to be powered by something lying between them. When astronomers pointed their telescopes at another source called 3C48, instead of finding the intricate structure they had found around Cygnus A, they saw a simple bright spot dominated by light in the blue end of the spectrum. It looked like a star, simple and featureless. But when they tried to measure spectra to figure out what 3C48 was made of, the forest of spectral lines that read off their instruments couldn’t be matched to any of the stars they knew, nor could they identify any of the elements that it was made of. There were many other objects they couldn’t identify. Cosmic radio sources were plentiful and different, and no one had a clue what or how far away they were.
Maarten Schmidt focused on a source that had the nondescript name of 3C273. It looked like a star, but the spectral lines were unlike any set he had seen before. Looking closely at his measurements, he found something quite remarkable: the spectral lines of the radio source matched those of hydrogen exactly if they were dramatically redshifted by almost 16 percent. Line by line he could match the two spectra. But to be redshifted by that amount, 3C273 was either hurtling away from us at speeds close to the speed of light or was so far away that the expansion of the universe was dramatically redshifting the spectra. Schmidt was stunned. That evening he told his wife, “Something terrible happened at the office today.”
It was a momentous discovery. Schmidt had found that these objects littered throughout the cosmos were billions of light-years away, and for such distant objects to be seen so easily in radio surveys and by large optical telescopes, they had to be belting out an enormous amount of energy. In fact, 3C273 and 3C48 were producing as much light as one hundred galaxies put together. They were like supergalaxies, much more powerful than anything that had been seen before.
These sources also had to be very, very small, only a fraction of the size of any other galaxy. The same was true of other sources in the 3C Catalogue—some were ten or even a hundred times smaller than ordinary galaxies. And when monitored closely, these sources seemed to be less than a few trillion kilometers across, “mere peanuts by cosmological standards,” as Time magazine wrote at the time. Copious amounts of energy were being produced at colossal distances from a very small region of space.
Something that inexplicable and bizarre was too tempting for Fred Hoyle. While continuing his battles defending the steady-state model of the universe, Hoyle had developed a formidable reputation as an expert on the structure of stars. With William (“Willy”) Fowler and Geoffrey and Margaret Burbidge, he had come up with a detailed explanation of how the elements in nature could all be synthesized in nuclear reactions in stars.
Fowler and Hoyle proposed that the radio stars were indeed stars, but not like any other stars. These stars would be superstars, with masses of a million or a hundred million suns like ours, so immense that they could produce tremendous amounts of energy during their lifetimes. And their lifetimes were short, for they burned up their energy so quickly that they would rapidly collapse in a brief, violent death. With their superstars, Hoyle and Fowler pushed the rules for understanding stars developed by Eddington well into the realm of the general theory of relativity. Einstein’s theory beckoned.
In the oppressive heat of the summer of 1963, a small group of relativists gathered in Dallas, Texas. They sat around the pool drinking martinis and discussing the strange, heavy objects that Maarten Schmidt had unlocked. They were an international bunch in Dallas for, as one of them put it, “American scientists outside of geophysics and geology would rarely deign to settle there. To most the region seemed to be as magnetic as Paraguay.” But Texas was to become an unlikely center for relativity, a shift driven mainly by the efforts of a hard-talking, gregarious Viennese Jew named Alfred Schild.
Schild had an itinerant childhood and youth, a product of the turmoil of the 1930s and 1940s. He was born in Turkey and lived in England as a child. Like Bondi and Gold, he was interned in Canada, where he studied physics under Leopold Infeld, one of Einstein’s disciples, and wrote a thesis on cosmology. He had been at the meet
ing in Chapel Hill in 1957, taking part in the excitement of general relativity’s next phase, and that year he was recruited to take up a professorship at the University of Texas at Austin.
Texas was a backwater when Alfred Schild arrived in Austin, but it was phenomenally rich from the oil income that was flowing through the local economy. Schild was able to cajole the university to put the oil money to good use, letting him set up his own Center for Relativity. With the air force keen to tap into the potentially magical powers of gravity, there was no shortage of money. And while the mathematicians at Austin looked down on Schild’s work, the physicists were willing to take him in.
Schild went looking for talent, and he definitely had a knack for finding it. The group of young relativists he assembled from Germany, England, and New Zealand transformed Austin, Texas, into an obligatory stopping point for any relativist worth his salt. Schild didn’t stop in Austin. In Dallas, the newly created Southwest Center for Advanced Studies was looking for young faculty to boost the “science starved south,” so Schild stepped in. Schild told them to invest in relativity, and so they did, hiring the center’s very own international group to build up the ranks of Texan relativity.
That July afternoon, the Texan relativists lounging by the pool cooked up a scheme that would bring the world to Texas to discuss relativity. It wouldn’t just be another Chapel Hill, small and freewheeling. This time they would bring in a whole new crowd, the astronomers, and try to rope them into thinking about Einstein’s theory by hosting a meeting focusing on radio stars, the “quasi stellar radio sources.” With Schmidt’s measurements of the previous March, it was clear that these strange objects were too massive and too distant to be treated using the old Newtonian laws of gravity. These were the big things that Chandra and Oppenheimer had alerted everyone to, the stars that would be too big to withstand the pull of gravity, and where general relativity could play such a dramatic role. In the invitation letter they sent out, the organizers proposed that “energies which lead to the formation of radio sources could be supplied through the gravitational collapse of a superstar.” The relativists called their meeting the Texas Symposium on Relativistic Astrophysics. It was to be held in December of 1963 in Dallas.
The Perfect Theory Page 14
