About Time
Page 22
Out of Goldschmidt’s census came a riddle: Why and how had the universe ended up with just this distribution of elements? When World War II ended, one nuclear physicist set out to use his new science to create a cosmology that could provide an answer.
George Gamow had never been conservative in his habits or his science. Born in Russia and trained under the tutelage of Friedmann, he chafed under the confines of Stalinism. In 1928 Gamow found a powerful explanation for one ubiquitous form of radioactivity called “alpha” decay.38 Using the fundamental uncertainty that was built into quantum mechanics, Gamow showed how nuclear particles (2 protons and 2 neutrons) could “tunnel” out of a larger nucleus, disappearing from inside the nuclear interior only to reappear outside and escape. The discovery gained him enough fame to allow his emigration to the United States in 1934.39 Irreverent, impatient and and a heavy drinker, in the United States he quickly enhanced his reputation for theoretical brilliance. For a scientist such as Gamow, Goldschmidt’s elemental abundances were too tempting to leave to someone else’s explanation. With typical insight and audacity, he leapt to the conclusion that Goldschmidt’s data were nothing less than a fossil record of cosmic history—a history that must have begun with a bang. To explain the elemental abundances, Gamow imagined an early universe that was a billion times denser and hotter than today’s. This ultradense, ultrahot starting point would be Gamow’s Big Bang. It would be the starting point for his calculation of the origin of the elements—a theory of cosmic nucleosynthesis.
Much had changed in the years between Lemaître’s primeval atom and the atomic bomb. The weapons developed in Los Alamos, New Mexico, were the products of a robust nuclear science. When Gamow began his cosmological work in 1946 a great deal of nuclear physics had already been discovered that went far beyond just the existence of protons and neutrons. A growing menagerie of new particles was being catalogued, particles with names such as muons and mesons. Physicists charted reactions between these subatomic particles to create a detailed working knowledge of nuclear chemistry, where quantum mechanical transformations turned one set of particles into another. Gamow’s audacious goal was to use this growing body of knowledge to map out the first moments of cosmic history and explain the elemental abundances we see today.
His first paper on the subject in 1946 outlined the basic idea.40 The relativistic cosmology of Friedmann and Lemaître would be the space-time container into which Gamow poured his nuclear physics. Just as in Lemaître’s primeval atom theory, Gamow began immediately after the beginning. Rather than a single all-encompassing primeval nucleus, Gamow imagined the early universe to be a soup—a primordial soup—of neutrons.41
Gamow proposed that well-timed nuclear reactions in this primordial soup were the explanation for Goldschmidt’s elemental abundances. Starting a fraction of a second after the dreaded singularity, Gamow’s theory had a cosmic timer built into it. As space-time expanded, according to the Friedmann-Lemaître solution, the temperature and density of the universe smoothly declined. As the temperature and density fell, a brief window in time would occur when conditions were just right to turn the entire universe into a nuclear reactor. All Gamow had to do was follow the details of the reactions and their dependence on the cosmic background of density and temperature and he was sure all the known elemental abundances could be recovered.
But details were not Gamow’s strong suit. He was a big-picture guy and putting meat on the skeleton of his grand idea required the heavy lifting of hours and hours of laborious calculations. To carry the idea to the next level Gamow asked his graduate student Ralph Alpher to take on the project. Alpher, the son of Jewish immigrants, had exactly the right balance of patience, technical competence and physical insight to take Gamow’s proposal and turn it into a theory complete with predictions.42
In 1948 Alpher and Gamow fleshed out important details in the model. The entire process of “nuclear cooking” began just 0.01 second after the universe began from the singularity (whatever that meant) and took less than a half hour to complete.43 At first the primeval soup of neutrons (which Alpher dubbed “Ylem”) would decay (meaning quantum mechanically transmute or transform) into protons and electrons. This transmutation created the first hydrogen nuclei (protons). Collisions between protons and neutrons would then lead to deuterons, a heavy form of hydrogen. Continued collisions would add neutrons and protons until helium, with its two protons and two neutrons, became abundant. Then, like a chain being built one link at a time, the other elements would follow until, just as Gamow had originally proposed, all the elements in the universe were built up with the abundances shown in Goldschmidt’s data.
FIGURE 7.4. Ralph Alpher with a slide rule, circa 1950.
As the pair prepared their manuscript for submission to the journals, Gamow, at the last minute, saw the opportunity for a joke he couldn’t resist. Referring back to the first letters of the Greek alphabet—alpha, beta and gamma—Gamow inserted the name of his friend Hans Bethe, a Nobel Prize–winning nuclear physicist, between his and Ralph Alpher’s in the authors list. Writing later, Gamow recalled,
Dr Bethe, who received a copy of the manuscript, did not object, and, as a matter of fact, was quite helpful in subsequent discussions. There was, however, a rumor that later, when the α, β, γ theory went temporarily on the rocks, Dr Bethe seriously considered changing his name to Zacharias.44
Ralph Alpher was not amused. He worried that having the names of two famous physicists on the paper would devalue his own (enormous) contribution to the work. History would, unfortunately, prove him right.
Gamow’s joke aside, the initial calculations in the Alpher, Bethe and Gamow paper seemed promising. A second paper in 1948 improved on the first by including parameters for key reactions only recently published by Argonne National Laboratory in Illinois (the lab was the fruit of the wartime nuclear physics effort). From 1948 to 1951, Alpher was joined by another young physicist, Robert Herman. Together they published a series of detailed papers uniting nuclear physics and its understanding of the very small with general relativity’s understanding of the very large. The synthesis created a new kind of cosmological theory describing the detailed evolution of space, time and matter.
The calculations of Alpher, Herman and Gamow were a tour de force of theoretical physics. Like an exquisitely choreographed ballet, all the known particles played their role on a space-time stage described by an expanding universe of general relativity. Each species in the subatomic zoo mixed with others and with particles of light (photons) in the ultrahot, ultradense primordial soup. Particle populations remained in perfect equilibrium, changing back and forth from one form to the other, until the cosmic expansion cooled and thinned the soup. Nuclear reactions depend on temperature and density. As the cosmic temperature dropped, some reactions slowed to a crawl, like a cake that stops baking as the oven cools. In this way the universe’s expansion carried the primordial soup through successive stages where some particle species stopped transmuting and were “frozen out” of the ongoing reactions. Their abundances became fixed for all the cosmic history to follow, becoming the nuclear fossils we find in our own era. By tracking these reactions and the successive freeze-outs, Alpher and his collaborators followed the nucleonic dance of the early universe through the age of the nuclear cooking. Within half an hour after t = 0 the nuclear show was over and the elemental abundances were set.
FIGURE 7.5. Nuclear “cooking” in the early universe. In the Alpher, Gamow theory of Big Bang nucleosynthesis, light atomic nuclei combine to form heavier nuclei. Here hydrogen nuclei (a single proton) combine to form helium nuclei (two protons and two neutrons). The universe is hot and dense enough for nucleosynthesis only during a brief period. All nuclear cooking ends a few minutes after the Big Bang.
Alpher, Gamow and Herman’s calculations would form the basis for all modern theories of the early universe. But when the work was published, the authors had a difficult time convincing scientists of its worth. The detailed
nuclear calculations were alien to most astronomers. More important, for the physicists who could follow the calculations, there was a hole in the theory that tamped enthusiasm for the Gamow-Alpher “hot Big Bang”.
Building heavy elements from light elements in a step-by-step fashion was the fundamental idea behind Gamow’s nuclear cooking. But experiments showed that there were no stable nuclei with collections of nucleons that summed to 5 or 8. If nuclear cooking, as Gamow imagined it, created a nucleus of beryllium-8 (4 protons and 4 neutrons), it quickly decayed and turned into a nucleus of lithium-7 (3 neutrons and 4 neutrons). Like trying to climb a staircase with missing steps, Gamow’s step-by-step nuclear cooking faced a “mass gap”. Heavier nuclei could not be formed because unstable lighter nuclei disappeared before they became part of the chain.
Gamow, with his typical disregard of details, was sure this mass gap was just a matter of details and would soon be solved. Throughout the 1950s, however, all attempts to cross the mass gap in a cosmological setting failed.45 While the Alpher-Gamow theory did a superb job predicting the abundances of the first two elements—hydrogen and helium—the heavier ones would not give way to their calculations, leaving other scientists sceptical of the entire enterprise.46
Alpher eventually left research physics to take a position with General Electric.47 There he worked on a number of projects including the physics of atmospheric reentry for ICBMs and other spacecraft. In one of cosmology’s most unfortunate episodes, Alpher went to his grave bitter that he had never received his full measure of credit for shaping the century’s dominant cosmological model. Herman also left academia. Gamow, for his part, shifted his emphasis to biology and left cosmological theorizing behind. Thus, the second discovery of Big Bang theory ended with a whimper. By the mid-1950s, most researchers were unaware of their work, but the researchers left a gift before departing the cosmological stage. It was a kind of Easter egg that would one day crack open to revolutionize the field. Buried within their papers was a prediction that would remain unnoticed for another decade until fate, time and telecommunications satellites intervened.
LONDON • JULY 23, 1962, 8 P.M.
“Ladies and gentlemen, we have just been informed that this baseball game is being seen in Europe, right now, over the Telstar satellite. Let’s give all the baseball fans in Europe a big hello from Chicago.”
FIGURE 7.6. Telecommunications satellite as rock star. Original album art for the Joe Meek song “Telstar,” performed by the Tornados.
Joe Meek was so excited he couldn’t keep himself on the piano bench. Baseball! All the way from America as it was happening! It was too much.
From the first moment of the telecast, when the American flag flickered on the screen, Meek was almost giddy. He might be a record producer with number-one hits now, but fifteen years ago he’d been a radar operator in the RAF. In all that time he’d never lost his passion for electronics, space exploration and the dream of what they both meant for the future.
He kept coming back to the image of Telstar sailing gracefully overhead in orbit, miles above the atmosphere. He wanted to make people see what he saw, a new world of wonders that was just beginning.
Within an hour Meek had most of the song, a tribute to Telstar, composed. He could feel it was going to be a hit. He knew it in his bones, just like that first time he’d produced Humphrey Lyttleton’s “Bad Penny Blues” five years before. On that song he’d used his expertise in electronics to compress the sound of Lyttleton’s piano. Hump had been so angry with him for “tinkering” with the sound—until the song went to number one. Meek knew his Telstar anthem would need a lot more electronic effects than that first effort. The song was about the future and it would have to sound like the future.
It only took another hour to finish and as he walked away from the piano Meek had to smile. This was going to work. Tomorrow he would call that band the Tornados and see if they wanted to make history with him.
DEPLOYING A GLOBAL NOW: THE BIRTH OF TELECOMMUNICATION SATELLITES
“Telstar”, a three-minute pop masterpiece, was rushed into production after Decca records heard the Tornados’ rendition of Meek’s composition. Overdubbed with a clavioline, an early version of an electronic keyboard, Meek gave the recording a signature eerie spacelike sound that hovered above the infectious triumphant melody. It was an instant hit, rocketing to the number one spot in the U.K. charts and remaining there for five weeks. But, like its namesake, “Telstar” would prove to be a global phenomenon. Within two weeks it crossed the ocean and the Tornados become the first British band to score a spot on the U.S. Billboard pop charts.48 What began with a grainy image of the American flag beamed from a passing satellite turned into the first salvo of the British pop invasion.
Just fourteen days before the historic broadcast, Telstar 1 blasted into orbit atop a Thor-Delta rocket.49 The launcher was, essentially, a modified ICBM.50 Like the continent-spanning nuclear missiles reshaping the Cold War, Telstar and the telecommunications satellites that followed represented another revolutionary form of material engagement which, like the missiles, had its roots in World War II.
Radar (an acronym for “radio detection and ranging”) was one of the most powerful technologies to emerge from the war. The ability to bounce radio waves off objects to detect, or target, distant enemies had obvious advantages. The development of radar accelerated in the late years of the conflict, but the atmosphere’s radio-sensitive upper layers (the ionosphere) posed a challenge to radar engineers. It was not clear at the time if the technology would be useful for targets at very high altitudes, such as orbiting missiles. As the war ended and the conflict with the Soviets began, the U.S. military knew it had to determine if radar could be utilized in space.
The U.S. Army quickly formed Project Diana with a single goal: to push radio signals through the ionosphere and bounce them off the moon. The generals did not have to wait long for results. On the morning of January 10, 1946, Project Diana’s Belmar, New Jersey, transmitting station was warmed up and ready to go. As the moon rose over the horizon the transmitter shot out a powerful blast of radio emissions. Just 2.5 seconds later (the amount of time it takes light to travel to the moon and back) the station’s oscilloscopes flickered. The dancing traces on the scope marked the echoed signal’s return. Humans had, for the first time, “touched” a celestial object and begun their space age.51
Another milestone was crossed eight years later when James Trexler, an engineer at the U.S. Naval Research Laboratory, spoke slowly into a microphone at the lab’s Maryland radio facility. After a 2.5-second delay, Trexler heard his words bounced back to him from the moon. With a human voice transmitted from the Earth to the moon and back again, communications and the high frontier of space were joined in scientists’ imaginations.52 The public’s imagination would come next.
It did not take long for both sides of the Cold War to lay their plans. In 1955 J. R. Pierce of Bell Labs wrote an influential article making the case for “orbital radio relays”—satellites that either passively reflected signals or more complex craft that received and rebroadcast signals. Pierce soon became a stalwart advocate for satellite communications and led many pioneering Bell Labs efforts, including the Telstar project.53
The development of ICBMs and work on communication satellite launch vehicles were a paired effort. By the late 1950s the United States was lifting payloads into low Earth orbit.54 In 1960 the newly created National Aeronautics and Space Administration (NASA) launched its first experimental communication satellite—a giant thirty-metre Mylar balloon called Echo 1. Echo was essentially an orbiting mirror, allowing telephone, radio and television signals to be bounced from the Earth to the rapidly moving satellite and back again. Such passive telecommunications platforms would be no substitute for an active re-broadcast of signals with greater power and accuracy. Active signal re-broadcast was Telstar’s job.55
New forms of material engagement require new forms of institutional behaviour. Just as time
synchronization in the era of the train and telegraph would demand conventions between nations, telecommunications satellites would require even higher levels of co-operation among institutions. Telstar was not a NASA project but a commercial venture of AT&T through Bell Labs, their extraordinary research wing. At the heart of the project was an array of multinational agreements between AT&T, NASA, Britain’s General Post Office and France’s PTT (Postes, Télégraphes et Téléphones), all designed to develop transatlantic satellite communications.56
With its first broadcast in 1962, Telstar caused a cultural sensation. In truth, however, the Telstar satellites were never destined to be more than a way station towards satellite communications. Two Telstars were put into operation but their low Earth orbit meant each spent only twenty “broadcast-serviceable” minutes above the horizon during their two-and-a-half-hour orbits. Geosynchronous satellites were the real solution for space-based instant telecommunications. Orbiting the Earth once every twenty-four hours, a geosynchronous satellite could be “parked” high above the equator, continuously broadcasting to almost any position below it. Just two years after Telstar, the 1964 Tokyo Olympics were broadcast live to the United States via the newly launched Syncom 3 satellite. One year later, Early Bird, the first commercial geosynchronous satellite, achieved orbit, and the world began its new experiment in culture and cultural time in earnest.57
For all the impact of television in the 1950s, the images it conveyed were essentially local. Film of distant events was shipped by plane back to TV studios. “The film had to be processed, edited and flown across oceans . . . before it could be broadcast”, said Walter Cronkite, recalling his own experience of Telstar’s impact (he shared anchoring duties of the first broadcast with Chet Huntley). Telstar transformed TV’s grasp of the world. “We had no idea”, said Cronkite, “that a technology so young would become master of events so quickly”.58 Just days before the 1969 moon landing, the last geosynchronous satellite needed to create a twenty-four-hour global network was eased into orbit. The world was linked together in a single simultaneous present just in time to watch the first human steps on the moon.59