by Bill Mesler
The two started to discuss how to approach the problem. They used Oparin’s theory as a guide for how the first life might have appeared, adjusting it to Urey’s theories of the early atmosphere’s composition. Hydrogen, Urey figured, was the key. Hydrogen was by far the most common element in the solar system. At the time, one other scientist was pursuing a similar course of experiments into the origin of life, a Berkeley biochemist named Melvin Calvin. Calvin was one of the world’s greatest authorities on the fabulously complex process of photosynthesis. He would be awarded a Nobel Prize in 1961 for explaining its underlying mechanism. Calvin assumed an early atmosphere consisting of carbon dioxide and water, energized by solar radiation. He simulated those conditions with an early particle accelerator, which had been invented at Berkeley by the nuclear scientist Ernest Lawrence. But Calvin’s results were disappointing. His experiments produced trace amounts of the organic compounds formic acid and formaldehyde, but too little to be seen as significant and not really the types of organic material that could be easily understood as leading to the origin of life.
Urey, on the other hand, brought a unique perspective to the problem. His expertise was in the chemical composition of stars and planets, and his theories led him to hypothesize a somewhat different primitive atmospheric composition than the one Calvin tried to simulate. The biggest difference in their outlook was the relative abundance of oxygen. Urey thought it unlikely that the early atmosphere had contained any of it at all, aside from what was present in clouds. The composition of the Earth had been changed by unique circumstances, most notably the presence of living things, with their abilities to produce oxygen as a by-product of photosynthesis. Urey proposed that the early Earth instead had a reducing atmosphere, filled with hydrogen, methane, and ammonia.* The presence of methane was particularly important because it contained carbon, an element present in all living cells. Urey’s hypothetical world was also turbulent, filled with frequent lightning storms. Since the eighteenth century, chemists had achieved remarkable results by subjecting gases to electric sparks. Electrical storms would have made the formation of organic materials easier.
Miller set about finding a way to construct a model of this early Earth. Working with the university glassblower, he began building a Pyrex version of Urey’s primitive environment in a series of connected flasks and tubing. One flask was meant to represent the early ocean and contained water that could be heated to simulate evaporation. A second flask contained the gases methane, ammonia, and hydrogen, Urey’s vision of the Earth’s early atmosphere. An electric Tesla coil functioned as a lighting proxy. At the press of a button, Miller could launch a pale, blue-violet electric arc between two electrodes. The flasks were connected by a U-shaped tube with a condenser that would return any organic compounds made in the atmosphere flask to the experimental ocean, simulating rain in Miller’s model Earth. Miller would go on to construct several models based on the design, one of which was capable of simulating volcanic heating. But his first simulation gained fame as one of the seminal experiments in the field of what would become known as “prebiotic chemistry.” It was dubbed “the classical apparatus.” Later, Scientific American published a do-it-yourself guide to re-creating Miller’s experiment, and its replication became something of a right of passage among amateur chemists.†
Stanley Miller and his “classical apparatus.”
The experiment started showing promise almost immediately. After running it for one day, Miller noticed that the interior walls of his experimental Earth were coated with a yellow substance and the primitive “ocean” had turned a rich brownish red. After just two days, Miller was able to detect the presence of the organic compound glycine, an amino acid commonly found in proteins. When he finally shut the experiment down after six days, he conducted a thorough chemical analysis of what had taken place inside the confines of his miniature early Earth.
When word of Miller’s experiment started to leak out into the small world of University of Chicago scientists, Urey was asked what he expected Miller to find. His answer was one word: “Beilstein.” This was an allusion to Beilstein’s Handbook of Organic Chemistry, ubiquitous in university libraries and containing detailed lists of all organic compounds known to date. In other words, Urey expected the apparatus to produce a little bit of everything. Instead, both men were astounded to see that a significant amount of the carbon present had been transformed into surprisingly few organic materials, including several types of amino acids. It was the best result they could have hoped for. Amino acids are the building blocks of the proteins that drive cellular metabolism. Most surprising, the amino acids that had formed in Miller’s apparatus were the right kinds of amino acids—particularly glycine and alanine, commonly found in proteins. Alexander Oparin had hypothesized that proteins would have necessarily been the first cellular components to appear on the primitive Earth. Here was experimental evidence that seemed to confirm the first steps in the Oparin-Haldane hypothesis of how life originated.
The results seemed too perfect to be true. Urey insisted on a slow, meticulous process of confirmation and reconfirmation. In the 1950s, measuring amino acids was still a relatively primitive practice that involved blotting paper with the sample and applying various dyes to test for the presence of various compounds. Eventually, Urey became convinced of the results, and it came time to publish.
By all rights, Urey was entitled to the lion’s share of the credit. In most labs, the professor assumes most of the credit and graduate students can expect at best a second billing. But Urey was at the point in his career where he took more pleasure from watching his protégé’s success than burnishing his own reputation. He understood that if they published the results under both of their names, Miller’s contribution would be treated as an afterthought, so he insisted the results be published under Miller’s name alone, a remarkably magnanimous gesture, considering the impact he knew the research was going to have.
Urey contacted the editors of the leading scientific journal in the United States, Science, and told them to expect the manuscript. But Urey’s decision to leave off his own name—and the weight of his scientific authority—proved problematic. Such a monumental discovery, Urey supposed, would be harder to accept coming from a mere graduate student. After months passed without any word from the magazine, Urey complained to Howard Meyerhoff, chair of the editorial board, eventually asking that the manuscript be returned so that he could submit it to the less prestigious Journal of the American Chemical Society. Soon, Meyerhoff contacted Miller directly and assured him that the work would appear shortly.
The paper was published on May 15, 1953. Almost immediately, it made headlines throughout the world. An editorial in the New York Times described the Miller-Urey apparatus as “a laboratory earth. . . . It did not in the least resemble the pristine earth of two or three billion years ago; for it was made of glass.” The Times went on to say that the experiment “made chemical history by taking the first step that may lead a century or so hence to the creation of something chemically like beefsteak or the white of an egg.” Time magazine reported that Miller and Urey had proved “that complex organic compounds found in living matter can be formed. . . . If their apparatus had been as big as the ocean, and if it had worked for a million years instead of one week, it might have created something like the first living molecule.” Alexander Oparin, reading the news in Moscow, doubted that the experiment could be true. Almost overnight, Miller became one of the most famous scientists in the world, and certainly the most famous American ever to have taken on the question of the origin of life.
IN OCTOBER OF 1957, a pair of Central Intelligence Agency officials stopped by Miller’s office. They were interested in a letter that Miller had recently received from Alexander Oparin. It was an invitation to a symposium that the Russian was hosting in Moscow on the origin of life, which Miller had accepted. In the four years since Miller’s experiment, the subject had been reinvigorated in the scientific community. Scores
of young physicists and chemists were drawn to the questions Miller and Urey had raised. And although he was just twenty-seven years old, Miller had already laid claim to the title of “godfather of prebiotic chemistry.”
For months, Oparin’s invitation had posed a dilemma for Miller. It had come during the height of the Cold War, just a year before the Berlin crisis. Joseph McCarthy had died earlier that year, falling victim to years of chronic alcoholism, but the climate of fear that McCarthyism had engendered lingered. This was particularly true in academia. The persecution of Robert Oppenheimer, the former head of the Manhattan Project, stood as a warning of what could happen if certain lines were crossed. The testimony against Oppenheimer given by Miller’s former professor, Edward Teller, had led to Teller’s ostracism in American academia.
A visit to Moscow was not a step Miller could take lightly. He had written to Harold Urey asking for advice. Urey was one of the many nuclear scientists to face scrutiny during the McCarthy hearings. He had argued on behalf of Julius and Ethel Rosenberg before their 1953 execution for stealing nuclear secrets on behalf of the Soviets. Later, Urey himself had been called before the House Un-American Activities Committee. Urey told Miller he had to make up his own mind but cautioned, “One never knows what a McCarthy will do in the future. It is a very sad situation.”
Miller decided to accept Oparin’s invitation. The visit from the CIA officers came shortly thereafter; they were visiting all the scientists headed to Moscow for the conference. Some in the upper levels of the US government feared that the Soviets might lay claim to creating life in a laboratory. Such a discovery would have represented a significant propaganda victory for the Soviet regime, and the Americans could ill afford any more of those. Earlier that month, the USSR had launched the first artificial satellite, Sputnik-1. Across the United States, amateur radio enthusiasts tuned in on their ham sets to hear the eerie cricket-like chirping of Sputnik’s radio transmitter as it hurtled, untouchable, over American airspace. The sound was quickly taped and rebroadcast on commercial airwaves to a shocked public. In December, the first American satellite was launched in response, only to explode ignominiously in front of a live national television audience. Newspaper headlines the next day bemoaned the failure of America’s “Stayputnik.” There was a growing perception that the USSR was gaining the upper hand in the scientific front of the Cold War.
Editorial cartoon appearing in the Washington Post, December 31, 1956.
The CIA agents wanted Miller to report back to them on the origin-of-life work being done in Moscow. Miller agreed but was flabbergasted by the agents’ inability to understand even the most basic facts about the subject they were investigating. When he returned, they spent most of their time debriefing him on the lack of air-conditioning in Moscow and the personalities of the scientists involved.
The origin of life was still a politically sensitive subject in the United States. It had been only three decades since the Scopes Monkey Trial in Tennessee, where three-time Democratic presidential candidate William Jennings Bryan had railed against the inability of science to explain the origin of life. After the results of the Miller-Urey experiment made news headlines, a Gallup poll asked whether it was possible “to create life in a test tube.” Only 9 percent of respondents thought it was. But Cold War competition between the superpowers trumped any domestic political sensitivities. The United States was about to embark on the most ambitious and far-reaching government-funded science program since the Manhattan Project, and the scientists studying the origin of life were going to play a major role.
LATER IN THE WINTER of 1957, a young Fulbright scholar from the University of Wisconsin named Joshua Lederberg stopped in for a visit with Haldane at the elder scientist’s home in Kolkata. Lederberg was just thirty-two years old, but he had already built an impressive reputation in the field of genetics for his discovery that bacteria could mate and exchange genetic information. Previously, bacteria were thought to simply pass genetic information to their offspring completely unchanged, creating exact copies of themselves. Lederberg had shown that their reproduction was much more complex. In 1958, Lederberg’s work on bacterial genetics would earn him the Nobel Prize in Physiology or Medicine.
Lederberg was one of those to receive an invitation to Oparin’s Moscow symposium. Ultimately, he had decided not to attend, opting to continue his work at the virologist MacFarlane Burnet’s laboratory in Melbourne, Australia. On his way home to Wisconsin, Lederberg decided to make a stop in India to pay his respects to Haldane, who had only just begun his self-imposed exile from Great Britain. There was a lunar eclipse that night, an event of great significance in Hinduism, and Lederberg had to make his way through streets crowded with religious revelers to get to Haldane’s home. Naturally, the two men’s conversation veered to the stars, and to the topic that was on almost everyone’s minds: the USSR’s launch of Sputnik. It was the fortieth anniversary of the October Revolution, and Haldane worried that the Soviets would try something daring. He wondered if they might try to make a show of their newfound military capabilities by exploding a nuclear weapon on the moon—a demonstration that would be visible on Earth. The men spent the evening lamenting the thought that the promise of space exploration was being lost to a game of geopolitical one-upmanship between the superpowers.
When he arrived back in the United States, Lederberg immediately set about trying to establish a toehold in the nascent American space program. Within a month, he had circulated two memos throughout the National Academy of Sciences discussing the potential for a new “cosmic microbiology” and “lunar biology.” Lederberg was advocating that the scientific search for the origin of life be extended to the space program as a search for life on other planets. Finding life in space would have important implications for the scientists trying to discover the origin of life on Earth. As a bacteriologist, Lederberg posed his suggestions as a matter of national security. He worried that the first life human beings would encounter in space would be bacterial and potentially very dangerous, capable of wreaking devastation much the way the introduction of bacteria from Eurasia had once devastated native populations in the wake of Columbus’s voyage to America, an idea that Lederberg popularized in an article entitled “Moondust” that he wrote for Science.
Lederberg’s suggestions grabbed the attention of Hugh Dryden, who was emerging as one of the most important figures in America’s rapidly expanding space program. In July of 1958, President Eisenhower signed the National Aeronautics and Space Act, creating NASA. Dryden was named the deputy administrator, and one of his first acts was to set up a Space Sciences Board to advise the new agency. Lederberg was named to head a panel on extraterrestrial life. From his new position, and with the enormous funding of the space program to draw upon, Lederberg began to attract some of the leading names in origin-of-life research, such as Harold Urey, Berkeley’s Melvin Calvin, and Stanley Miller, who was already speculating about the possible presence of life on other planets. Lederberg also began snatching up some of the most promising young minds in the field.
One of the men Lederberg recruited was a young astrophysicist named Carl Sagan, who had been a student of Urey’s at the University of Chicago when Miller conducted his electrical discharge experiment. Sagan quickly became one of the most enthusiastic embracers of the space program, and he carried his enthusiasm for understanding the origin of life with him when he left Chicago. His unique knack for popularizing science was apparent almost from the beginning—something that Lederberg and his coterie of scientists would benefit from in the years to come.
By 1959, the term “exobiology” had begun to appear in Lederberg’s private letters to describe the way in which the search for the origin of life on Earth could be used to hunt for life in outer space. The term caught on quickly. But at its root, the work always remained focused, ultimately, on the search for the origin of life on Earth. As Carl Sagan later wrote, exobiology was nothing more than “extending [Stanley] Miller’s results to ast
ronomy.”
At the start of the 1950s, research into the origin of life was pitifully underfunded and neglected at universities. The Miller-Urey experiment had come about only by what Miller later called “bootlegging” funds marked for other research. They staged the whole experiment for less than a thousand dollars. But by the early 1960s, research into the origin of life had begun to draw on the seemingly bottomless pockets of the American space program. As early as 1959, money began to pour in for work on instruments to detect life on other worlds. Twenty years after it was created, NASA was easily the world’s largest funder of origin-of-life research in the world.
One of the first to receive a grant was Wolf Vishniac, a microbiologist and exobiologist at Yale Medical School, who received funding for a device to detect microorganisms present in the soil of other planets. He named his device the “Wolf Trap.” In the coming decades, scientists from the exobiology program would be instrumental in the Apollo missions to the moon, and central to the Viking missions to Mars. They went on to produce important new theories, such as the Gaia hypothesis and the grim potential climatic effects of a “nuclear winter” resulting from atomic warfare. And as they searched for signs of life on other planets, they continued to take important steps toward understanding just how life arose on Earth.
That understanding was about to change in some very fundamental ways. Just a few weeks after the results of the Miller-Urey experiment were published, a team of scientists in Great Britain would tease apart the molecular structure of DNA, a discovery that, in the years to come, was going to upend everything that scientists believed about the mechanisms of biological inheritance. The search for the origin of life—and even the most basic understanding of how life was constructed—was about to undergo a major revolution. Much of it would play out among the scientists affiliated with the NASA exobiology program.