Four Revolutions in the Earth Sciences

Four Revolutions in the Earth Sciences: From Heresy to Truth

James Lawrence Powell
Copyright Date: 2015
Pages: 384
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  • Book Info
    Four Revolutions in the Earth Sciences
    Book Description:

    Over the course of the twentieth century, scientists came to accept four counterintuitive yet fundamental facts about the Earth: deep time, continental drift, meteorite impact, and global warming. When first suggested, each proposition violated scientific orthodoxy and was quickly denounced as scientific--and sometimes religious--heresy. Nevertheless, after decades of rejection, scientists and many in the public grew to acknowledge the truth of each theory.

    The stories behind these four discoveries reflect more than the fascinating push and pull of scientific work. They reveal the provocative nature of science, which raises profound and uncomfortable truths as it advances. For example, the Earth and the solar system are older than all of human existence; the interactions among the moving plates and the continents they carry account for nearly all of the Earth's surface features; and nearly every important feature of our solar system results from the chance collision of objects in space. Most surprising of all, we have altered the climate of an entire planet and threaten the future of human civilization. This absorbing scientific history is the only book to describe the evolution of these four ideas from heresy to truth, showing how science works in practice and how it inevitably corrects the mistakes of its practitioners. Scientists can be wrong, but science can be trusted. In the process, astonishing ideas are born and, over time, take root.

    eISBN: 978-0-231-53845-9
    Subjects: General Science, Geology, Environmental Science, Physics, History of Science & Technology

Table of Contents

  1. Front Matter
    (pp. I-VIII)
  2. Table of Contents
    (pp. IX-X)
  3. List of Illustrations
    (pp. XI-XII)
  4. Preface
    (pp. XIII-XIV)
  5. Introduction
    (pp. XV-XVI)

    During the twentieth century, scientists made four fundamental and surprising discoveries about the Earth: our planet is billions of years old, continents and ocean floors move, rocks as big as mountains fall from the sky, and humans are changing the climate. When first proposed, each violated long-held beliefs and quickly came to be regarded as scientific, and sometimes religious, heresy. Then, after decades of rejection, scientists reversed themselves and came to accept each theory. Today, scientists regard deep time, continental drift, meteorite impact, and anthropogenic global warming as established truths.¹

    The aim of this book is describe how each idea...

    • The Abyss of Time
      (pp. 3-8)

      In September 1846, the faculty of the University of Glasgow convened to examine an applicant for its chair in natural philosophy, the previous holder, appointed in 1803, having passed on after a lengthy illness. At age twenty-two, the candidate, William Thomson (1824–1907), was easily mistaken for a student himself. In spite of his youth, the Cambridge graduate had already accomplished more than enough to justify his candidacy, but there was one additional hurdle. Before an appointment could become official, the applicant had to write and deliver, in Latin, an essay assigned by the faculty. Thomson’s topic was to be...

    • A Great Mistake Has Been Made
      (pp. 9-14)

      In 1892, the queen made William Thomson a peer of the realm. He chose the name “Kelvin,” for a small stream that wends its way near the University of Glasgow.¹ Some thirty years before, Kelvin, as we will henceforth refer to him, had come to despise Lyell’s theory, but not for any of the reasons already given. Indeed, Kelvin operated from too lofty a perch to become embroiled in geology’s internecine squabbles. His objection came from a higher plane: physics.

      Lyell’s philosophy envisioned an eternal, unchanging Earth. To supply the energy necessary to keep the planet running, Lyell appealed to...

    • The Bank of Time
      (pp. 15-22)

      Even using their own methods to calculate the age of the Earth, geologists could not escape Kelvin’s influence. Each calculation from geology depended on its own assumptions, and each gave at least a slightly different answer. How could an individual calculator tell whether his result was anywhere close to right? In the second half of the nineteenth century there was only one way, and that was to compare one’s result with that of the lone external authority: Lord Kelvin. The temptation proved irresistible to the geological calculators, who “produced an amazing variety of methods and an even greater homogeneity of...

    • Account Overdrawn
      (pp. 23-31)

      As we saw, in 1868 Archibald Geikie had endorsed Kelvin’s 100-million-year timescale. Over the decades, he watched as the fund of time available to geology shrank until the science approached temporal bankruptcy. In his 1892 presidential address to the British Association, Geikie defected. His erudite, eloquent, even romantic defense of the science of geology is one that every student of the subject and anyone interested in the history of science would benefit from reading.¹ With hindsight, we can see how it bridged the descriptive methods of the nineteenth century and the quantitative ones that were to arrive in the twentieth....

    • Strange Rays
      (pp. 32-37)

      The decade of the 1890s was a time of great progress in science. No year in that decade was more eventful than 1895. In Sweden, Svante Arrhenius was calculating the effect of atmospheric CO₂ on global temperature, while in Britain John Perry was exposing the fallacy of Kelvin’s assumptions. The Scottish chemist William Ramsay discovered helium, previously known only from the Sun’s spectrum, in an earthly mineral. Helium would not only help explain what had eluded Kelvin—the true source of the Sun’s energy—but help refute his claims about the age of the Earth. In the town hall at...

    • An Hourglass of Great Precision
      (pp. 38-43)

      In 1903, Rutherford carried out an experiment that his biographer said demonstrated “remarkable ingenuity—even for Rutherford.”¹ He separated the alpha and beta particles and measured the velocity of the alphas, finding that they travel at the fantastic speed of 24,000 kilometers per second, or about 54 million miles per hour. Rutherford observed that the alpha particles have about twice the mass of a hydrogen atom, from which he could deduce that they were almost certainly helium. Since the energy of a moving object is one-half its mass times its velocity squared, Rutherford could calculate the energy of the alphas,...

    • Geochronology
      (pp. 44-53)

      To Kelvin and Rutherford, the age of the Earth and its constituent rocks and minerals were of secondary interest. Kelvin was intent on correcting the great mistake of British popular geology—belief in Lyellian uniformitarianism—and the age of the Earth and the Sun provided the means. He had enough other interests practical and theoretical to occupy several ordinary careers: thermodynamics; laying a cable under the Atlantic Ocean; writing a textbook with Tait; and inventions that included an improved compass, a machine to sound the depth of the ocean, and one to predict the tides.

      Rutherford wanted to use radioactivity...

    • Duck Soup
      (pp. 54-62)

      Although Rutherford left behind his early interest in measuring mineral ages, his subsequent research, along with that of the other pioneers, led to a series of surprising discoveries that were crucial to establishing the true age of the Earth. These fertile early years were an era of “little science”—research conducted on a laboratory bench at minor expense with apparatus that today seems not much advanced beyond string and sealing wax. But with only string and sealing wax, Rutherford was a virtuoso.

      Rutherford’s collaborator, Frederick Soddy, found that whereas the lead in uranium minerals has an atomic weight of just...

    • An Idea to Pursue
      (pp. 65-70)

      In 1911, Alfred Wegener, a young professor of meteorology, wrote to his sweetheart, a professor’s daughter, to describe his excitement over a friend’s new atlas. “For hours we examined and admired the magnificent maps,” he wrote. “At that point a thought came to me. Does not the east coast of South America fit exactly against the west coast of Africa, as if they had once been joined? The fit is even better if you look at a map of the floor of the Atlantic and compare the edges of the drop-off into the ocean basin rather than to the present...

    • A Very Trusting Man
      (pp. 71-80)

      As a professor of meteorology at the University of Marburg, Alfred Wegener was naturally interested in past climates. The authority on the subject in Germany, if not the world, was Professor Wladimir Köppen. In 1908, Alfred visited the Köppen home to seek the elder scientist’s advice about research that he planned during an upcoming expedition to Greenland. Later Wegener visited again, this time to show Köppen his book manuscript, titledThermodynamics of the Atmosphere, which would be published in 1911.¹ The young scientist may have had another reason for the return visit: in 1913, after his second expedition to Greenland,...

    • Dead on Arrival
      (pp. 81-86)

      Wegener’s 1912 paper drew little notice from English-speaking geologists, which was no surprise since neither had Taylor’s 1910 article, and his had appeared in theBulletin of the Geological Society of America. Unlike Wegener, Taylor had supplied a mechanism to support his theory of crustal sliding: the Earth’s capture of a passing comet. But given the unlikelihood of such an event, Taylor might have been better off to have left well enough alone.

      World War I prevented English speakers from reading either of the first two editions of Wegener’sThe Origin of Continents and Oceans. The third edition appeared in...

    • Geologists Unite Against Heresy
      (pp. 87-95)

      Robert Newman sets the stage for the next important event:¹

      In the crucial 1922– 1933 period, six of the twelve presidents of the GSA [the Geological Society of America] were on public record in their presidential addresses as opposing drift; of the other six, only one, Reginald Daly of Harvard, took a mobilist position. Of geologists elected to the National Academy of Sciences during this period, ten were active opponents of mobilism,all of them committed before the notorious AAPG debate.

      All the vocal opponents of mobilism were elites, and they stood united . . . against heresy.²

      Thus by...

    • Continental Drift: Not Even Wrong
      (pp. 96-107)

      With the publication of his first scientific paper in 1911, Arthur Holmes started on a path that would soon establish him as the leading authority on the age of the Earth.¹ He would remain so well into the 1950s. But Holmes had an equally longstanding interest in another aspect of radioactivity: heat production. Since the days of his mentor Robert Strutt, geologists had known that radioactive elements were widely distributed in the Earth’s crust and that the heat they produce must have played a role in the thermal evolution of the Earth. Holmes set out to uncover that role.


    • Postwar Surprises
      (pp. 108-114)

      In 1965, a young Princeton postdoctoral student named W. Jason Morgan (b. 1935) shared an office with the geologist Fred Vine (b. 1939), newly arrived from Cambridge University. Morgan had been poring over photographs of the Moon, seeing what he could deduce from the heights of the walls and central peaks of lunar craters. Vine’s interests were more down to Earth: the geophysics of the seafloor. His enthusiasm proved contagious, and before long officemate Morgan had switched his interest from the faraway Moon to the inaccessible deep-sea trenches. Morgan began to explore Holmes’s idea that a pair of descending convection...

    • Wandering Poles or Drifting Continents?
      (pp. 115-122)

      Paleomagnetic research proceeded in two phases. First came the effort to establish the reliability of rock magnetism. Second came the research into the strange magnetic reversals and whether they could be used to determine rock ages. Not one of the pioneering paleomagnetists set out to corroborate continental drift. British physicists like Blackett and Runcorn knew little geology and were mainly interested in magnetism for its own sake. Their lack of knowledge may have been a handicap, but if so it was one they quickly remedied by recruiting geologists to assist them. And perhaps it was not a handicap after all....

    • The Final Confrontation
      (pp. 123-130)

      By the mid-1950s, all who had spoken at the 1926 AAPG symposium or written a chapter for the publication were dead. Daly, the only prominent American geologist willing even to consider drift, had died in 1957. Students of the 1950s, now two geological generations removed from Schuchert and Willis, might never have heard of continental drift. The historian of geology Robert H. Dott, who was in graduate school in the early and mid-1950s, recalls, “I had not heard of continental drift or Alfred Wegener until a fellow graduate student—rather than a faculty member—introduced me to those heretical names.”¹...

    • Spreading Seafloors
      (pp. 131-143)

      By 1964, paleomagnetic research was already shifting direction. No longer would the emphasis be on determining past pole positions, which had already confirmed drift to the satisfaction of anyone with an open mind. Now the research swung to using the magnetic reversals to date rocks. To everyone’s surprise, including the scientists involved, it would turn out to be the reversals, more even than the differing apparent polar wandering curves, that would ultimately corroborate continental drift. But first the paleomagnetists had to convince themselves that the reversals reflected actual changes in the Earth’s magnetic field rather than being attributable to self-reversal...

    • HypotHESSes
      (pp. 144-151)

      Let us now return to Fred Vine, at Cambridge in January 1962, listening to Harry Hess. The talk so inspired young Vine that he titled his own forthcoming student address to the Cambridge Geology Club “HypotHESSes.” In the early 1960s, it was a rare geologist who knew and accepted both that the Earth’s magnetic field had reversed and that the seafloors were spreading from the ridges. Hess’s ideas had reached the broader geological community only with the Buddington volume in November 1962, and such a specialized book typically is not widely read. Being able to hear directly from Hess early...

    • The Discovery of the Century
      (pp. 152-157)

      Tuzo Wilson had opened his 1965 article on transform faults with this prescient paragraph:

      Movements of the Earth’s crust are concentrated in mobile belts, which may take the form of mountains, mid-ocean ridges or major faults with large horizontal movements. These features and the seismic activity along them often appear to end abruptly, which is puzzling. The problem has been difficult to investigate because most terminations lie in ocean basins. [These] mobile belts divide the surface intoseveral large rigid plates

      On the second page, he wrote: “The plates between the mobile belts are not readily deformed except at their...

    • All This Rubbish
      (pp. 158-164)

      Though by the 1970s the majority of geologists had come to accept drift, some never did: Bucher, Ewing, and Jeffreys, for example. How should we judge these dissenters? They were wrong, but it is the fate of scientists to be wrong. The best, like Hess, take pride in their errors and move on to the next novel suggestion. But those who continue to insist they were right the first time, in spite of accumulating evidence to the contrary, are stuck forever with their original belief. They are entitled to their opinions, but they can also influence their students and followers...

    • A Trivial Process
      (pp. 167-173)

      The Hopi Reservation of the Colorado Plateau is one of the most isolated spots in the continental United States. The night sky appears just as our ancestors saw it, filled with a myriad of brilliant stars, bisected by a luminous Milky Way, and early on the rise of the full Moon, host to an enormous golden orb. In this setting, one’s thoughts of an evening naturally turn to the heavens and their mysteries.

      In the late 1950s, a self-described “rather brash young man,” a precocious geology graduate of the California Institute of Technology, was working for the USGS mapping a...

    • To Hunt a Star
      (pp. 174-184)

      Isaac Newton showed that the Earth and the Moon are bound by an invisible yet irresistible force from which neither will ever escape: gravity. One might say that the relationship resembles that of the members of a family, which include spouses, siblings, and sons and daughters, whose bonds not even death can part. No wonder then that scientists came to nickname the three prominent explanations of the Moon’s origin the daughter, sister, and spouse theories. One of them we met in part 2.

      Although we see tides ebbing and flowing in the oceans, Newtonian mechanics requires that the solid Earth...

    • The Moon’s Face
      (pp. 185-190)

      In reading the literature on lunar craters, one is surprised to find names familiar from another of the great discoveries reviewed in this book: continental drift. The initial surprise comes because we expect scientists to have worked in narrow disciplinary niches, as they do today. We recognize that a few always defy pigeonholing, but we hardly expect them to be right and the experts wrong. Yet one lesson of this book is that these outsiders not only are often right; they are indispensable to science.

      During 1918 and 1919, while Alfred Wegener was adozentat the University of Marburg,...

    • Rosetta Stone
      (pp. 191-196)

      In early 1941, the astrophysicist Ralph B. Baldwin (1912–2010) was an instructor of astronomy at Northwestern University and on the verge of becoming a father. In order to support his soon-to-be-enlarged family, Baldwin began to moonlight by giving lectures at Chicago’s Adler Planetarium, for four dollars each. When he arrived early, he would wander the halls, examining the Adler’s exhibits and especially its superb photographs of the Moon. One in particular caught Baldwin’s eye: it showed a set of “long valleys with raised rims” that he had never seen mentioned in the literature. He noticed that these valleys “pointed...

    • To a Rocky Moon
      (pp. 197-201)

      On the fourth of October 1957, the Shoemaker family in the Hopi Buttes and the rest of the world awoke to the beep-beep of the eighty-four-kilogram Russian satelliteSputniksailing far overhead.Homo sapienshad left its home planet and taken its first step toward the stars. Not only was Gene Shoemaker unprepared; so was nearly everyone else in America. The United States had no space program and, as would shortly become all too apparent, no reliable rockets with which to launch anything into space. As to the most obvious target of a space program—the Moon—no one knew...

    • Worlds in Collision
      (pp. 202-210)

      On the evening of July 20, 1969, families around the world gathered in front of their television sets, hoisting infants aloft so the youngsters could later claim they had witnessed an event unique in human history, even in the history of the universe. Right on schedule, Astronaut Neil Armstrong (1930–2012) ofApollo 11stepped down from the Lunar Lander onto the surface of Mare Tranquillitatis. Armstrong had conceived a memorable quote but in the emotion of the moment did not deliver it perfectly, an outcome familiar to any public speaker, and he was speaking to and for the entire...

    • Dinosaur Killer
      (pp. 211-218)

      In 1980, a paper appeared inSciencetitled “Extraterrestrial Cause for the Cretaceous-Tertiary Extinction.”¹ The authors were the father-son team of Luis and Walter Alvarez, together with their University of California colleagues Frank Asaro and Helen Michel. The Cretaceous-Tertiary boundary, known as the K-T, is the point in geological time at which the dinosaurs and 70 percent of all species became extinct, one of the five big mass extinctions in earth history.²

      Though none of the four authors was a paleontologist, they claimed to have solved one of the most venerable puzzles of the fossil record: what killed the dinosaurs?...

    • Out with a Bang
      (pp. 219-228)

      How did the impact skeptics react to the discovery of the putative K-T crater? By now, the reader is not apt to respond, “they instantly accepted it without reservation.” Correct. In 1992, Officer and Drake, together with Arthur Meyerhoff, one of the few who still rejected plate tectonics, wrote a paper in Geology Today titled “Cretaceous-Tertiary Events and the Caribbean Caper.” It described several potential K-T craters, concluding that the Chicxulub structure was nothing special, merely another alleged impact crater on a list of easily discredited candidates.¹

      The Chicxulub site failed the test for two reasons, they said. First, it...

    • Cosmic Pinball
      (pp. 229-236)

      By the mid-1980s, though Penfield and Camargo had reported the existence of the Chicxulub crater, no one seemed aware of it, and the controversy over the Alvarez theory continued to bubble. But what was no longer in doubt was that many terrestrial meteorite impact craters exist. Already by 1970, some fifty had been identified. Today the number exceeds 180. Hundreds, thousands more must have formed but be inaccessible or have been removed by erosion.

      But what of the largest collision of all, the giant impact that may have created the Moon? How had that theory fared? By 1984, fifteen years...

    • Origins of the CO₂ Theory
      (pp. 239-245)

      Never in recorded history had England been colder than the winter of 1962–1963. The Thames froze solid, affording Londoners their third “Skating Christmas” in a row. In Sussex, by Boxing Day nine inches of snow had piled up, then two more fell. According to theMid Sussex Times, “1962 went out bleakly and dismally, leaving a heritage of blizzard havoc, snowbound roads and traffic dislocation to the infant New Year.”¹

      For Sussexman Guy Stewart Callendar, shoveling up the rare white flakes, the blizzards and low temperatures were a special disappointment: they appeared to refute his life’s most important work....

    • Tedious Calculations of Extraordinary Interest
      (pp. 246-254)

      The Sun’s rays shine not only in the visible part of the spectrum but over a range from infrared to ultraviolet. Since the atmosphere absorbs infrared radiation rising from the Earth’s surface, as Pouillet noted, it must also absorb infrared rays entering the atmosphere from the Sun. To understand the Earth’s heat budget, it is necessary to know how much heat the Sun provides before its rays begin to be affected by the atmosphere. Tyndall had been delighted to learn that an American scientist had emulated de Saussure by carrying to the mountaintop an instrument to measure that quantity, known...

    • Destructive Criticism
      (pp. 255-264)

      In the 1890s, as Arrhenius was making his onerous calculations, scientists like Langley were just beginning to explore the absorption of the Sun’s rays by atmospheric gases. In Sweden, a physicist named Knut Ångström and his assistant, Herr J. Koch, filled a 30 cm tube with CO₂, sent heat radiation through it, and measured the fraction that came out the other end. Next Herr Koch reduced the amount of CO₂ in the tube by one-third and repeated the measurement. But it made little difference: barely any more heat radiation passed through the cylinder. Thus it appeared that the smaller amount...

    • A Unique Experiment of Planetary Dimensions
      (pp. 265-270)

      One reason that Callendar’s 1938 paper did not inspire follow-up was that scientists could think of nothing to do to test the CO₂ theory. In the short run it did not appear to be true, as through the 1940s global temperatures fell. And as Callendar had pointed out, the oceans might well soak up enough excess CO₂ so that even though the greenhouse effect is real, it is too small to matter. Then came a world war. New instruments and methods, whose origins lay in their military applications, brought a revolution in the practice of science.

      During the war and...

    • Giant Brains
      (pp. 271-277)

      Scientists first began to use digital computers during World War II to calculate artillery firing tables and to break enemy codes. But even before the war ended, some meteorologists and pioneering computer scientists realized that in principle a digital computer could solve the complex equations needed for numerical weather prediction.

      The first attempts used the ENIAC (Electronic Numerical Integrator and Computer), which had been built by scientists at the University of Pennsylvania between 1943 and 1945. The “Giant Brain,” as the press dubbed the machine, had at most ten words of read/write memory, yet its 18,000 vacuum tubes, six thousand...

    • Warming Is Unequivocal
      (pp. 278-288)

      A sound theory makes predictions that can be tested and, when they are, turn out to be true. As we saw, the Hansen group’s 1981 paper made a number of predictions. In today’s era of record-setting temperatures, it is easy to lose sight of the most important one, which at that time even many scientists did not accept: that global temperatures would rise. They have, and they will.

      By the end of the first decade of the twenty-first century, other predictions from the paper were also coming true. The Northwest Passage opened, Arctic sea ice reached its lowest extent in...

    • From Heresy to Truth
      (pp. 289-298)

      Why did scientists reject the four theories discussed in this book for so long, only to have later generations come to regard them as virtually self-evident? The answer is now plain: scientists accepted the theories when the data demanded that they do so. To call themselves scientists, they had no choice.

      But at first the data were missing or open to different interpretations. Kelvin’s calculations of the age of the Earth depended not on data but on Fourier’s mathematics and Kelvin’s assumption that the Earth was born molten and has no unknown source of heat. The data of the hourglass...

  10. Acknowledgments
    (pp. 299-300)
  11. Notes
    (pp. 301-328)
  12. Recommended Reading
    (pp. 329-332)
  13. Bibliography
    (pp. 333-350)
  14. Index
    (pp. 351-368)