The Science Book

by Clifford A Pickover

  The word laser is an acronym for light amplification by stimulated emission of radiation, and lasers make use of a subatomic process known as stimulated emission, first considered by Albert Einstein in 1917. In stimulated emission, a photon (a particle of light) of the appropriate energy causes an electron to drop to a lower energy level, which results in the creation of another photon. This second photon is said to be coherent with the first and has the same phase, frequency, polarization, and direction of travel as the first photon. If the photons are reflected so that they repeatedly traverse the same atoms, an amplification can take place and an intense radiation beam is emitted. Lasers can be created so that they emit electromagnetic radiation of various frequencies.

  In 1953, physicist Charles Townes and students produced the first microwave laser (maser), but it was not capable of continuous radiation emission. Theodore Maiman created the first practical working laser in 1960, using pulsed operation. In 1961, dermatologist Leon Goldman was first to use a laser to treat melanoma (a skin cancer), and related methods were later used for removing birthmarks and tattoos with minimal scarring. Because of the speed and precision of laser surgery, lasers have since been used in ophthalmology, dentistry, and many other fields. In LASIK eye surgery, a laser beam is used to change the shape of the eye’s cornea to correct for nearsightedness and farsightedness. In prostate surgery, a laser may be used to vaporize tumors. Green laser light can be used for coagulation when the light is absorbed by hemoglobin to stop a bleeding blood vessel. The hot beam of a surgical laser can be used to cauterize, or seal off, open blood vessels as the beam moves along tissue.

  SEE ALSO Sutures (c. 3000 BCE) Newton’s Prism (1672), Wave Nature of Light (1801).

  An optical engineer studies the interaction of several lasers for potential use aboard a laser-weapons system being developed to defend against ballistic missile attacks. The U.S. Directed Energy Directorate conducts research into beam-control technologies.

  1961

  Cracking the Genetic Code for Protein Biosynthesis • Michael C. Gerald with Gloria E. Gerald

  George Gamow (1904–1968), Francis Crick (1916–2004), Rosalind Franklin (1920–1958), Robert W. Holley (1922–1993), Har Gobind Khorana (1922–2011), Marshall Warren Nirenberg (1927–2010), James D. Watson (b. 1928), J. Heinrich Matthaei (b. 1929)

  The structure of DNA was determined in 1953 by Watson, Crick, and Franklin, with strands of the double helix consisting of four nucleotides: adenine (A), thymine (T), cytosine (C), and guanine (G); in RNA, uracil (U) replaces T. But how was the genetic information contained in the DNA molecule translated to the biosynthesis of a protein?

  The Russian physicist George Gamow postulated that a three-letter nucleotide (codon) could define up to sixty-four amino acids, more than sufficient to code for all twenty amino acids used to build proteins. In 1961, Marshall Nirenberg, with J. Heinrich Matthaei at the National Institutes of Health, sought to determine what amino acid would be formed after a single nucleotide was added to a reaction mixture. UUU produced the amino acid phenylalanine, cracking the first letter in the genetic code. Shortly thereafter, the addition CCC was found to yield proline. Har Gobind Khorana at the University of Wisconsin-Madison produced more complex sequences composed of repeated two-nucleotide sequences, the first of which was UCUCUC, read as serine-leucine-serine-leucine . . . ; subsequently, the remainder of the codons were determined.

  In 1964, Robert Holley, at Cornell University, discovered and established the chemical structure of transfer RNA (tRNA), thus providing the link between the role of messenger RNA (mRNA) and ribosomes. The information needed to make a protein is first attached to tRNA and then translated to messenger mRNA in a ribosome. Each tRNA only recognizes one set of three nucleotides in mRNA, and tRNA binds to only one of the twenty amino acids. A protein is formed by the addition of one amino acid at a time. Nirenberg, Khorana, and Holley were jointly awarded the 1968 Nobel Prize.

  Apart from variations, the genetic codes used by all forms of life are very similar. Based on the theory of evolution, the genetic code was established very early in the history of life.

  SEE ALSO DNA Structure (1953), Ribosomes (1955), Central Dogma of Molecular Biology (1958), Human Genome Project (2003).

  This image depicts the relationship between the codon (the three-letter nucleotide consisting of adenine, thymine, cytosine, and guanine or uracil) and the encoding of amino acids.

  1961

  First Humans in Space • Jim Bell

  Yuri Gagarin (1934–1968), Alan Shepard (1923–1998)

  The Soviet Union’s successful launch of Sputnik 1 in 1957 marked the beginning of the Space Age, as well as the beginning of an epic geopolitical race for technological, military, and moral superiority with the United States. The Russians had launched the first animal into space—a dog named Laika onboard Sputnik 2—and the US was launching monkeys and chimpanzees, but both governments knew that the next big victory in the space race could only be claimed by launching a person into space.

  The Soviet human spaceflight program was called Vostok, and, like the original Sputnik effort, it was based on adapting existing intercontinental ballistic missile rockets to accommodate a small passenger capsule. About 20 Soviet Air Force pilots were secretly screened for the privilege of becoming the first cosmonauts (“space sailors” in Russian); the man chosen to be first was Senior Lieutenant Yuri Gagarin. At the same time, the US human spaceflight program, called Project Mercury, was on a parallel track, modifying the Redstone missile to accommodate its small single-passenger capsule. Seven test pilots, from the air force, navy, and marines, were ultimately selected and became instant celebrities, even before their flights. Navy test pilot Alan Shepard was chosen to fly the first Mercury mission.

  Both Vostok and Mercury had early (unmanned) launch failures; both teams had to demonstrate that their rockets would work with an empty capsule before government leaders would authorize a human-piloted flight. Both teams were neck and neck in the race to launch a person first in early 1961, and once again the Soviets scored an enormous international victory by successfully sending Gagarin into space first, for one orbit of Earth in Vostok 1 on April 12, 1961. Three weeks later, Shepard became the second person—and first American—launched into space with his successful suborbital flight in the Freedom 7 capsule.

  The Russians had again taken the lead. But America upped the ante shortly after Shepard’s flight, when president John F. Kennedy, in an address to Congress, called for NASA to land a man on the moon before the decade was out.

  SEE ALSO Wright Brothers’ Airplane (1903), Saturn V Rocket (1967), First on the Moon (1969).

  Cosmonaut Yuri Gagarin preparing to board his Vostok 1 spacecraft on the morning of April 12, 1961. Seated behind him was his backup, cosmonaut German Titov, who eventually piloted Vostok 2 in August 1961, becoming the second person to orbit the Earth.

  1961

  Green Revolution • Marshall Brain

  Norman Borlaug (1914–2009)

  Between 1950 and 1987, world population doubled from 2.5 billion to 5 billion people. It was a startling surge. And humans were already putting a strain on food supplies. In 1943, for example, 4 million people in India (6 percent of the population) died in a famine.

  During that period of surging population, there was a problem brewing: at then-current production levels, the world had no way to produce enough food to feed everyone. The process that prevented mass starvation—the development that saved a billion or more lives—began in 1961, and was called the Green Revolution. Biologists and engineers worked together to spread advanced agricultural technologies around the world, championed by American biologist and humanitarian Norman Borlaug, who became a spokesperson for these initiatives.

  A big factor in improving food production happened at the biological level, by breeding and, later, genetically engineering better strains of cereal grains like wheat and rice. Biologists took an engineer’s problem-solving approach—they were trying
to breed plants that could make use of more nitrogen, while at the same time putting the nitrogen into grain production rather than stem construction. The biologists wanted short, stocky stems so the plants would not fall over. They also wanted to reduce the time to harvest. They were able to pull this off by finding and incorporating dwarf strains and other useful characteristics to create high-yield crops.

  These new strains of plants needed water and fertilizer. Engineers could respond to those needs with irrigation projects and new ways of increasing fertilizer production. Then they went a step further: in warm climates it is possible to put in two crops a year, but only if there is enough water to support the second crop. With the rainy season supplying the water for one crop, a country like India needed a way to store water for the second crop. So engineers built thousands of new dams in India to catch the water from monsoon rains and hold it. Now India could grow twice as much food.

  The effect of these improvements was startling. World food production doubled, then doubled again. Even though population was growing, the food supply grew faster. Science and engineering together created a farming revolution.

  SEE ALSO Agriculture (c. 10,000 BCE), Domestication of Animals (c. 10,000 BCE), Rice Cultivation (c. 7000 BCE) Photosynthesis (1947).

  The engineering innovations that came about as a result of the Green Revolution were numerous, and included new strains of rice meant to create higher yields for famine-stricken regions.

  1961

  Standard Model • Clifford A. Pickover

  Murray Gell-Mann (b. 1929), Sheldon Lee Glashow (b. 1932), George Zweig (b. 1937)

  “Physicists had learned, by the 1930s, to build all matter out of just three kinds of particle: electrons, neutrons, and protons,” author Stephen Battersby writes. “But a procession of unwanted extras had begun to appear—neutrinos, the positron and antiproton, pions and muons, and kaons, lambdas and sigmas—so that by the middle of the 1960s, a hundred supposedly fundamental particles have been detected. It was a mess.”

  Through a combination of theory and experiment, a mathematical model called the Standard Model explains most of particle physics observed so far by physicists. According to the model, elementary particles are grouped into two classes: bosons (e.g., particles that often transmit forces) and fermions. Fermions include various kinds of Quarks (3 quarks make up both the proton and Neutrons) and leptons (such as the Electron and Neutrino, the latter of which was discovered in 1956). Neutrinos are very difficult to detect because they have a minute (but not zero) mass and pass through ordinary matter almost undisturbed. Today, we know about many of these subatomic particles by smashing apart atoms in particle accelerators and observing the resulting fragments.

  As suggested, the Standard Model explains forces as resulting from matter particles exchanging boson force-mediating particles that include photons and gluons. The Higgs particle is the fundamental particle predicted by the Standard Model that explains why other elementary particles have masses. The force of gravity is thought to be generated by the exchange of massless gravitons, but these have not yet been experimentally detected. In fact, the Standard Model is incomplete, because it does not include the force of gravity. Some physicists are trying to add gravity to the Standard Model to produce a grand unified theory, or GUT.

  In 1964, physicists Murray Gell-Mann and George Zweig proposed the concept of quarks, just a few years after Gell-Mann’s 1961 formulation of a particle classification system known as the Eightfold Way. In 1960, physicist Sheldon Glashow’s unification theories provided an early step toward the Standard Model.

  SEE ALSO String Theory (1919), Neutron (1932), Quarks (1964), Theory of Everything (1984), Large Hadron Collider (2009).

  The Cosmotron. This was the first accelerator in the world to send particles with energies in the billion electron volt, or GeV, region. The Cosmotron synchrotron reached its full design energy of 3.3 GeV in 1953 and was used for studying subatomic particles.

  1963

  Chaos and the Butterfly Effect • Clifford A. Pickover

  Jacques Salomon Hadamard (1865–1963), Jules Henri Poincaré (1854–1912), Edward Norton Lorenz (1917–2008)

  To ancient humans, chaos represented the unknown, the spirit world—menacing, nightmarish visions that reflected man’s fear of the uncontrollable and the need to give shape and structure to his apprehensions. Today, chaos theory is an exciting, growing field that involves the study of wide-ranging phenomena exhibiting a sensitive dependence on initial conditions. Although chaotic behavior often seems “random” and unpredictable, it often obeys strict mathematical rules derived from equations that can be formulated and studied. One important research tool to aid in the study of chaos is computer graphics. From chaotic toys with randomly blinking lights to wisps and eddies of cigarette smoke, chaotic behavior is generally irregular and disorderly; other examples include weather patterns, some neurological and cardiac activity, the stock market, and certain electrical networks of computers. Chaos theory has also often been applied to a wide range of visual art.

  In science, certain famous and clear examples of chaotic physical systems exist, such as thermal convection in fluids, panel flutter in supersonic aircraft, oscillating chemical reactions, fluid dynamics, population growth, particles impacting on a periodically vibrating wall, various pendula and rotor motions, nonlinear electrical circuits, and buckled beams.

  The early roots of chaos theory started around 1900 when mathematicians such as Jacques Hadamard and Henri Poincaré studied the complicated trajectories of moving bodies. In the early 1960s, Edward Lorenz, a research meteorologist at the Massachusetts Institute of Technology, used a system of equations to model convection in the atmosphere. Despite the simplicity of his formulas, he quickly found one of the hallmarks of chaos—that is, extremely minute changes of the initial conditions led to unpredictable and different outcomes. In his 1963 paper, Lorenz explained that a butterfly flapping its wings in one part of the world could later affect the weather thousands of miles away. Today, we call this sensitivity the butterfly effect.

  SEE ALSO Gödel’s Theorem (1931), Cellular Automata (1952), Fractals (1975).

  Chaotic mathematical pattern, created by Roger A. Johnston. Although chaotic behavior may seem “random” and unpredictable, it often obeys mathematical rules derived from equations that can be studied. Very small changes of the initial conditions can lead to very different outcomes.

  1963

  Cognitive Behavioral Therapy • Clifford A. Pickover

  Epictetus (55–135), Albert Ellis (1913–2007), Aaron Temkin Beck (b. 1921)

  Cognitive behavioral therapy (CBT), which emphasizes the role of errors in thinking in producing negative emotions, has ancient roots. The Greek Stoic philosopher Epictetus wrote in the Enchiridion, “Men are disturbed not by things, but by the view which they take of them.” In CBT, the psychotherapist helps the patient think about situations and circumstances in new ways, in order to change patients’ reactions and feelings. If the patient can identify maladaptive or irrational thoughts, the thoughts can be challenged. The resultant improved behaviors serve to educate the patient further and to reinforce the more productive way of thinking. A patient commonly keeps a diary of events and associated feelings and thoughts.

  In the 1950s, American psychoanalyst Albert Ellis shaped the development of CBT, partly because of his dislike of the seemingly inefficient and indirect nature of classical psychoanalysis. Ellis wanted the therapist to be heavily involved in helping the client modify unhelpful patterns of thought. In the 1960s, American psychiatrist and psychoanalyst Aaron Beck became the major driving force behind modern CBT.

  CBT has often been shown to be helpful in many cases of depression, insomnia, anxiety, obsessive-compulsive disorder, post-traumatic stress disorder, eating disorders, chronic pain, and schizophrenia. When seeing a therapist, a patient is sometimes asked to reframe a thought in terms of a hypothesis that can be tested. In this manner, the patient can “step bac
k” from the belief to allow more objective examination and arrive at a different view. For example, a depressed person may overgeneralize, concluding she will never get a job after a single failed interview. For phobias and compulsions, symptoms are sometimes decreased by gradual exposure to a fearful stimulus. Depressed people may be asked to schedule small pleasurable activities (e.g., meet a friend for coffee). Not only does this modify behavior, but it can be used to test a belief or hypothesis such as “No one enjoys my company.” CBT can also be used in conjunction with medications for very serious psychological disorders.

  SEE ALSO The Principles of Psychology (1890), Psychoanalysis (1899), Classical Conditioning (1903), Antidepressant Medications (1957), Theory of Mind (1978).

  Using CBT and controlled, gradual exposure to spiders, a therapist can often treat arachnophobia. Functional magnetic resonance imaging studies suggest that CBT can affect the brain in a variety of useful ways.

  1964

  Brain Lateralization • Michael C. Gerald with Gloria E. Gerald

  Wilder Penfield (1891–1976), Herbert Jasper (1906–1999), Roger Wolcott Sperry (1913–1994), Michael Gazzaniga (b. 1939)

  In the 1940s, at McGill University’s Montreal Neurological Institute, the famed Canadian neurosurgeon Wilder Penfield was treating severely epileptic patients by surgically destroying specific brain areas from which the seizure was thought to originate. Prior to operating, he applied very slight electrical stimulation to discrete regions of the motor and sensory cortex and, with his colleague, the neurologist Herbert Jasper, mapped the body part that responded to stimulation. Together, they constructed a homunculi (“little man”) map representing specific parts of the body affected by motor and sensory brain sites.