While Thomson was discovering the electron in England, Antoine Henri Becquerel and Marie Skłodowska Curie were discovering the disintegration of atoms in France, what Madame Curie called “radioactivity.” Becquerel believed that the mysterious radiations recently observed to emanate from uranium, the so-called X-rays, were the result of the absorption of sunlight. The uranium X-rays, in turn, could be detected by nearby photographic plates. When Becquerel did his experiment, on February 26, 1896, Paris was cloudy. His uranium did not receive any energizing sunlight. On a whim, he decided to develop his photographic plates anyway. To his surprise, the photographic plates were strongly exposed, showing that the uranium emitted some kind of radiation on its own, without needing to be powered by the Sun. Later experiments by Becquerel showed that the radiations were electrically charged particles of some kind because they were deflected by magnetic fields, as were Thomson’s electrons. After the discoveries of Becquerel, Madame Curie did further studies of uranium rays and found that the uranium atoms were hurling out tiny pieces of themselves. A year later, Curie found the same atomic disintegrations with another element, radium. The indivisible atom was, after all, divisible. And what lay inside? No one knew. The bottom of the universe had fallen out.

  Here is the reaction of historian Henry Adams in 1903 to these disturbing developments:

  As history unveiled itself in the new order, man’s mind behaved like a young pearl oyster, secreting its universe to suit its conditions until it had built up a shell of nacre that embodied its notions of the perfect…He sacrificed millions of lives to acquire his unity, but he achieved it, and justly thought it a work of art.

  “One God, one Law, one Element” [Adams quoting Tennyson]

  Suddenly, in 1900, science raised its head and denied…the man of science must have been sleepy indeed who did not jump from his chair like a scared dog when, in 1898, Mme. Curie threw on his desk the metaphysical bomb she called radium.

  * * *

  —

  With his new corpuscles in hand, Professor Thomson proposed what became called the “plum pudding” model of the atom: a tiny ball filled uniformly with a “pudding” of positive electrical charge, into which were sprinkled the negatively charged electrons. You needed the positively charged pudding to balance out the negatively charged electrons, since it was known that most atoms are electrically neutral.

  Fifteen years later, the great physicist from New Zealand, Ernest Rutherford, and his assistants found that the atom was not a pudding at all. It was more like a peach. A hard nut resided at its center, containing all of the positive charge and nearly all of the mass. The new particles residing within that hard central nut were called protons and neutrons. Protons have positive electrical charge, neutrons have no charge. This peach picture emerged after Rutherford’s team fired subatomic particles at a thin sheet of atoms. Some of the particles veered off at large angles, as if they had hit something hard, a hard nut in the atom. With pudding, the deflections should have been small. “It was quite the most incredible event that had ever happened to me in my life,” boomed Rutherford. “It was almost as incredible as if you fired a 15-inch shell at a piece of tissue paper and it came back and hit you.” The hard nut at the center of each atom, the “atomic nucleus,” is a hundred thousand times smaller than the atom as a whole. To use an analogy, if an atom were the size of Fenway Park, the home stadium of the Red Sox in Boston, its dense central nucleus would be the size of a mustard seed, with the electrons gracefully orbiting in the outer bleachers. In fact, 99.99999­99999­999 percent of the volume of an atom is empty space, except for the haze of nearly weightless electrons. Since we and everything else are made of atoms, it is literally a fact that we are mostly empty space. That vast emptiness is perhaps the most unsettling consequence of dividing the indivisible.

  Eventually, Rutherford’s protons and neutrons, at the center of the atom, would themselves be found to consist of even smaller particles called quarks.

  Were we falling and falling without end? Were there unlimited infinities on all sides of us, both bigger and smaller, as Pascal believed? It is an unpleasant sensation. I am reminded of the Escher drawing Ascending and Descending, which depicts a line of cloaked men walking around a quadrangle in a medieval castle. The disturbing feature of the picture, achieved through a trick of perspective, is that the walkers are always ascending, marching up a continuously rising staircase, and yet after completing the loop they end up exactly where they began. It is a staircase without beginning or end. It is a staircase that goes nowhere.

  Escher made Ascending and Descending in 1960, at a time when physicists had recently discovered hundreds of novel subatomic particles in the new “atom smashers” and in high-energy radiations from space. The field of research into elementary particles and forces was thrown into chaos. In addition to the electrons and protons and neutrons, there were now delta particles and lambda particles, sigmas and xis, omegas, pions, kaons, rhos, and more. When the Greek alphabet was exhausted, the confounded physicists resorted to using Latin letters. Some of these new subatomic particles had total lifetimes, from the moment they were created to the moment they disappeared, of a mere 10-21 seconds, or 0.00000­00000­00000­00000­1 seconds. Before, even with the sacred atom fractured, there had been some kind of order. There had been only the electrons and protons and neutrons. But now—this howling zoo. There seemed to be no fundamental particles, no bottom to the infinite spiral down, no organizing principles.

  Then quarks were discovered in the late 1960s. Temporarily, the plummeting stopped. Each of the hundreds of new particles could be understood as a particular combination of a half-dozen basic quarks. Quarks offered a new system for organizing the subatomic zoo. Quarks were the new protons and neutrons, which, in turn, had been the new atoms. I once asked physicist Jerry Friedman, co-discoverer of quarks, whether he thought that the quark was the end of the line, the smallest unit of matter. “Probably,” he answered. He gave reasons. But he hesitated. “I could be surprised,” he said with a grin. “There are always surprises in science.” Surprises in science are good things, and bad.

  * * *

  —

  The philosophers of ancient Greece developed a terrifying view of the world called Zeno’s Paradox. Suppose you want to walk 15 feet across a room. Before you travel that distance of 15 feet, however, you must go halfway, which is 7.5 feet. And before you go that 7.5 feet, you must travel half of that distance, 3.75 feet. And before you go that 3.75 feet…And so on. In their minds, the philosophers kept chopping space into halves, into smaller and smaller dimensions ad infinitum, as did Pascal centuries later. The indivisible was pitted against the divisible. The ultimate conclusion of this intellectual exercise is that you cannot cross the room. In fact, you cannot move even an inch. You are frozen in a metaphysical conundrum. You are trapped by the infinity of the small.

  When scientists and mathematicians talk about infinity, they are usually imagining a sequence of bigger and bigger spaces and numbers. But infinity can go in the other direction as well. Jerry Friedman, physicist rather than philosopher, is more hopeful. He thinks that the quarks may be the end of the line.

  Other physicists disagree. In the last forty years, physicists have proposed objects far smaller than quarks, called “strings.” Instead of being point particles, like electrons, strings are extremely tiny one-dimensional “strings” of energy. Their sizes would be the Planck length, where gravity and quantum physics are joined. (See the earlier chapter “Between Nothingness and Infinity.”) An important property of strings is that they occupy a space of nine or ten dimensions, instead of the familiar three. In our world of tables and trees, we would not be aware of the additional dimensions because they are curled up into ultra-tiny loops. In the same manner, a garden hose appears as a line when seen at a distance.

  Strings were originally proposed as a theory of the strong nuclear force. In more recent years, they have been hypothesized as part of a theory of quantum gravity—that is, Einstein’s theory of gravity, general relativity, revised to include quantum physics. At present, no one knows how to test string theory or even whether it can be tested—the sizes are so tiny. Although the mathematics of the theory is beautiful and, in fact, the theory may be the only path to quantum gravity, some physicists have abandoned the theory. For one thing, it may be impossible to test. For another, it has turned out that there are many, many different versions of string theory, each with different outcomes and each corresponding, possibly, to a different universe, with different properties. In that case, our universe would be just one random cosmos, a throw of the dice—defeating the long-standing hope of physicists to show that our universe must necessarily be the way it is and no other way, given a small number of “first principles,” in the same way that a crossword puzzle has only one solution.

  Regardless of whether strings actually exist, we know that space and time lose their meaning at the Planck size, as discussed in “Between Nothingness and Infinity.” We cannot find smaller “particles” beyond Planck; we cannot divide space into smaller elements beyond Planck. It took two thousand years to measure the size of the hypothesized atom. In 1899, Max Planck hypothesized the “Planck length” as the unique length formed by combining his newfound quantum constant with the speed of light and Newton’s gravitational constant. Will it be another two thousand years before we can test the existence of strings?

  Modern Prometheus

  “I am by birth a Genevese, and my family is one of the most distinguished of that republic.” So begin the reminiscences of Victor Frankenstein in Mary Shelley’s famous novel. While at university, during a lightning storm, young Victor sees a stream of fire emerge from a beautiful old oak tree. He becomes enamored of all things scientific and proceeds to study electricity, biology, chemistry, and the new science of galvanism. “One of the phenomena which had peculiarly attracted my attention,” recalls Victor years later, “was the structure of the human frame, and, indeed, any animal imbued with life. Whence, I often asked myself, did the principle of life proceed? It was a bold question, and one which has ever been considered as a mystery.” After days and nights of laborious experiments, Victor succeeds in discovering how to bring lifeless matter to life. Almost immediately, he decides that he is not satisfied with the bare secret of life but wants to create a human being, with all the intricacies of fibers, muscles, veins—and a brain.

  What was the secret that Victor uncovered? For centuries, human beings have puzzled over the mystery of life. What makes an odd hodgepodge of molecules organize itself into living cells, which pulsate and squirm, feed on their surroundings, and then reproduce? Each of us emerged from the cells of our parents, who emerged from their parents, who emerged from their parents, back and back through the dark halls of time. We accept that astounding descent as a given. But how did it start? Surely, that beginning, the origin of life on our planet, and perhaps the origin of life in the entire cosmos, has a significance akin to the origin of the universe itself, borne from the nothingness from which came all matter and energy.

  The great biologist Louis Pasteur claimed that life could come only from previous life: Omne vivum ex vivo. However, few modern biologists believe that life existed in the early days of our primordial planet, a seething ball of chemicals freshly cooked in the cauldrons of a primordial star. How did it start? Was it an inevitable result of zillions of collisions of atoms, likely to happen on other planets with Earth-like conditions? Or was it a unique occurrence, a one time event? And can physics and chemistry and biology ever give definitive answers to such questions?

  Besides these profound scientific questions of origins, there is the philosophical and theological question of the materiality of life. Put your finger under a microscope, and you will see cells. Red blood cells, for example, look like red dimpled disks. Examine these cells with a higher-powered microscope, and you’ll see tiny hexagons, the molecules of hemoglobin. An even higher power microscope reveals intricate filigrees of oxygen and hydrogen atoms, carbon and nitrogen atoms clustered around an atom of iron. Is that what we are? Is that all that we are?

  Until recent times, biologists divided into two camps on the question of life.

  The so-called mechanists believe that a living creature is just so many atoms and molecules, microscopic pulleys and levers, chemicals and currents—all subject to the laws of chemistry and physics and biology. For that camp, the question of origins amounts to the structure and behavior of atoms and simple molecules, and the energies available in the primitive Earth. Vitalists, on the other hand, argue that there is a special quality of life—some immaterial or spiritual or transcendent force—that enables a jumble of tissues and chemicals to vibrate with life. That transcendent force would be beyond physical analysis or explanation. Some call it the soul. The ancient Greeks called it pneuma, meaning “breath” or “wind.” Judaism, Christianity, and Islam all hold that the breath of the soul can be imparted only by God.

  Modern biologists are mechanists. In fact, an entire interdisciplinary field called synthetic biology is concerned with manufacturing and manipulating components of living systems—aided in part by the discovery of the structure of DNA in the early 1950s and the beginnings of molecular biology. Some synthetic biologists are reprogramming the DNA of microorganisms to produce drugs and batteries and new engineering devices. Others want to understand how life originated on Earth. Still others are attempting to create new forms of life from prior living organisms. Or life from completely nonliving material.

  It is a young field. In the 1950s, chemists showed that electrical discharges (lightning) in a mixture of gases thought to represent the ancient atmosphere could produce amino acids, the building blocks of proteins. The first creation of a synthetic cell occurred in the late 1950s and early 1960s. The first hybrid gene, achieved by splicing together the genes of two different organisms, occurred in the early 1970s. The first synthesis of a complete set of genes from their chemical parts and injection into a host cell occurred in 2010. As important as they are, none of these accomplishments comes close to the creation of life from nonlife. However, given the historical momentum of science and the fortitude of the scientists involved, that result is probably only a matter of time. The first human-made life-form, created from scratch, will almost certainly be a single cell with a single gene, far simpler than a bacterium. But that will be a major advance.

  Such a result would be the ultimate triumph of the mechanist view. Yet the idea that we may be nothing but material atoms and molecules deeply disturbs many of us. Putting aside for the moment theological considerations, the feeling of selfhood, of thinking and emotion, of self-awareness, of “I-ness” is so overwhelming, so absolutely unique, so impossible to explain, that it seems incomprehensible such a sensation could be rooted completely in material atoms and molecules. It seems impossible that we, and other living beings, could be nothing but material. Yet that is the axiom of the synthetic biologists, who are embarked on a project to create life from nonlife.

  If they succeed, their success will reopen many deep questions. At the same time, the ability to create life from nonlife may represent the ultimate freedom of a living being. Not that we will have escaped the laws of nature. But we will have escaped the cosmic decree that living matter emerges from prior living matter in an inevitable chain, unknowing and autonomous, most of it utterly insensible but even the sentient organisms ignorant of the origins of their exquisite bodily machinery. Sometime in childhood, we become aware of ourselves as separate from the surrounding world, as conscious and thinking beings. But we do not remember our birth, or what came before. We understand only a fraction of the trillions of chemical and electrical processes taking place every moment under our skin. We do not know how and why the marvel of our lives, or any life, occurs. We can only accept what is given. If the synthetic biologists succeed in creating life from nonlife, we will be a rare substance in the universe that not only is aware of itself but also understands the secrets of its being.

  * * *

  —

  It is quite possible that the first creation of a living cell from scratch will occur in the laboratory of Jack Szostak, professor of genetics at the Harvard Medical School and professor of chemistry and chemical biology at the Massachusetts General Hospital. Professor Szostak was born in the early 1950s, just at the time that Rosalind Franklin and Francis Crick and James Watson were making their momentous discoveries about DNA. Szostak grew up in various cities in Germany and Canada as his father, an aeronautical engineer with the Royal Canadian Air Force, was transferred from one posting to the next. For his early fascination with science, Szostak credits his engineer father, who built a basement lab for his son. “The experiments I conducted there often made use of remarkably dangerous chemicals that my mother was able to bring home from the company where she worked,” recalls Szostak. He also credits his father with his decision at an early age to become an academic. “My father was often unhappy with his job, chafing at both his superiors and his subordinates. This I am sure made me seek out the academic life for its more egalitarian aspects. I have never felt like I worked for a boss or had employees who worked for me, just colleagues who like me were interested in learning more about the world around us.”

 

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16