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FUNDAMENTAL BUILDING BLOCKS 299 See also: Albert Einstein 214–21 ■ Erwin Schrödinger 226–33 ■ Georges Lemaître 242–45 ■ Paul Dirac 246–47 ■ Sheldon Glashow 292–93 fundamental importance because The Higgs boson destroys itself the theory of “spontaneous it answered the question “why within trillionths of a second of being symmetry breaking,” which are some force-carrying particles born. It is created when other particles explained how the particles that massive while others are massless?” interact with the Higgs field. mediate the weak force, the W and Z bosons, are massive, while Fields and bosons on skis are like low-mass particles, protons and gluons have no mass. Classical (pre-quantum) physics while those that sink into the snow This symmetry breaking was imagines electrical or magnetic experience a greater mass as they crucial in the formulation of the fields as continuous, smoothly travel. Massless particles, such as electroweak theory (pp.292–93). changing entities spread through photons and gluons—the force- Higgs showed how the Higgs space. Quantum mechanics rejects carriers of the electromagnetic and boson (or rather the decay products the notion of a continuum, so fields strong nuclear forces respectively— of the boson) should be detectable. become distributions of discrete are unaffected by the Higgs field “field particles” where the strength and sail straight through, like geese The search for the Higgs of the field is the density of the field flying over the field. boson spawned the world’s particles. Particles passing through largest science project, the Large a field are influenced by it via The hunt for the Higgs Hadron Collider—a giant proton exchange of “virtual” force-carrying In the 1960s, six physicists, collider with a 17-mile (27-km) particles called gauge bosons. including Peter Higgs, François circumference, buried 300 ft (100 m) Englert, and Robert Brout, developed underground. When running full The Higgs field fills space— tilt, the LHC generates energies even a vacuum—and elementary similar to those that existed just particles gain mass by interacting after the Big Bang—enough to with it. How this effect occurs can create one Higgs boson every be explained by analogy. Imagine billion collisions. The difficulty is a field covered in thick snow that spotting its traces among a vast skiers and people in snowshoes shower of debris—and the Higgs must cross. Each person will take is so massive that, on appearing, more or less time, depending on it decays instantly. However, after how strongly they “interact” with nearly 50 years of waiting, the the snow. Those that glide across Higgs has finally been confirmed. ■ Peter Higgs Born in Newcastle-upon-Tyne, Englert–Higgs field, because his England, in 1929, Peter Higgs 1964 article described how the earned undergraduate and particle could be spotted. Higgs doctoral degrees from King’s claims to have an “underlying College, London before joining incompetence” since he did not the University of Edinburgh as study particle physics at the PhD a Senior Research Fellow. After a level. This handicap did not stop stint in London, he returned to him from sharing the 2013 Nobel Edinburgh in 1960. Walking in the Prize in Physics with François Cairngorm Mountains, Higgs had Englert for their work in 1964. his “one big idea”—a mechanism that would enable a force field to Key works generate both high-mass and low-mass gauge bosons. Others 1964 Broken Symmetry and the were working along similar lines, Mass of Gauge Vector Mesons but we talk of the “Higgs field” 1964 Broken Symmetries and the today, rather than the Brout– Mass of Gauge Bosons

300 SYMBIOSIS IS EVERYWHERE LYNN MARGULIS (1938–2011) IN CONTEXT C harles Darwin’s theory of cells arise? The answer lay in evolution coincided with a endosymbiosis—a theory that was BRANCH cellular theory of life that first proposed by Mereschkowsky Biology emerged in the 1850s, asserting in 1905, but was only accepted that all organisms were made of after an American biologist called BEFORE cells, and new cells could only Lynn Sagan (later Margulis) 1858 German doctor Rudolf come from existing ones by a furnished the evidence in 1967. Virchow proposes that cells process of division. Some of their arise only from other cells, and internal components, such as food- Complex cells with internal are not formed spontaneously. making chloroplasts, apparently structures called organelles—the reproduced by division too. nucleus (which controls the cell), 1873 German microbiologist mitochondria (which release Anton de Bary coins the term This last discovery led Russian energy), and chloroplasts (which “symbiosis” for different kinds botanist Konstantin Mereschkowsky conduct photosynthesis)—are of organisms living together. to the idea that chloroplasts may found in animals, plants, and many once have been independent life microbes. These cells, now called 1905 According to Konstantin forms. Evolutionary and cellular eukaryotic, evolved from simpler Mereschkowsky, chloroplasts biologists asked: how did complex bacterial cells, which lack and nuclei originated by a organelles and are now called process of symbiosis, but his prokaryotic. Mereschkowsky theory lacks evidence. imagined primordial communities of the simpler cells—some making 1937 French biologist Edouard food by photosynthesis, others Chatton divides life forms by preying on their neighbors and cell structure, into eukaryote engulfing them whole. Sometimes (complex) and prokaryote the engulfed cells were left (simple). His theory is undigested and, he suggested, rediscovered in 1962. became chloroplasts—but without proof, this theory of endosymbiosis AFTER (living together and within) faded. 1970–75 US microbiologist Carl Woese discovers that Mitochondria are organelles that New evidence chloroplast DNA is similar make the energy-carrying chemical The invention of the electron to that of bacteria. adenosine triphosphate (ATP) inside microscope in the 1930s, combined a eukaryotic cell. This mitochondrion with advances in biochemistry, has been artificially colored blue.

FUNDAMENTAL BUILDING BLOCKS 301 See also: Charles Darwin 142–49 ■ James Watson and Francis Crick 276–83 ■ James Lovelock 315 The complex cells of The organelles— animals and plants nucleus, mitochondria, contain organelles, which are lacking in the simpler and chloroplasts— duplicate by division cells of bacteria. of preexisting organelles. These organelles The DNA of chloroplasts Lynn Margulis lived independent lives and mitochondria is similar to that Lynn Alexander (later Sagan, before coming of bacteria. then Margulis) entered together in the process Chicago University at just 14, before earning a PhD at of endosymbiosis. the University of California, Berkeley. Her interests in the Symbiosis is everywhere. cellular diversity of organisms led her to revive and champion helped biologists to unlock the up” the oxygen in their energy- the evolutionary theory inner working of cells. By the 1950s, releasing processes. These became of endosymbiosis, which scientists knew that DNA provided mitochondria: the “power packs” of biologist Richard Dawkins has genetic instructions for carrying cells today. At first, this appeared described as “one of the great out life processes and was relayed farfetched to most biologists, but achievements of 20th-century from generation to generation. In the evidence for Margulis’s theory evolutionary biology.” eukaryotic cells, DNA is packaged gradually became persuasive, in the nucleus, but it is also found in and it has now been widely For Margulis, cooperative chloroplasts and mitochondria. accepted. For example, the DNA of interactions were as important mitochondria and chloroplasts are as competition in driving In 1967, Margulis used this made from circular molecules—just evolution—and she viewed discovery as evidence to revive and like the DNA of living bacteria. living things as self-organizing substantiate the endosymbiosis systems. She later supported theory. She included the suggestion Evolution by cooperation was James Lovelock’s Gaia that there had been an oxygen not something new: Darwin himself hypothesis that Earth, too, “holocaust” in the early history of had conceived the idea to explain could be viewed as a self- life on Earth. About two billion the mutually beneficial interplay regulating organism. In years ago, as photosynthesizers between nectar-giving plants and recognition of her work, she flourished, they saturated the world pollinating insects. But few had was made a member of the with oxygen, which poisoned many thought it could happen so US National Academy of of the microbes around at the time. intimately—and fundamentally— Science and received the Predatory microbes survived by as when cells merged together at National Medal of Science. engulfing others that could “soak the very dawn of life. ■ Key works 1967 On the Origin of Mitosing Cells 1970 Origin of Eukaryotic Cells 1982 Five Kingdoms: An Illustrated Guide to the Phyla of Life on Earth

OUARKS COME IN THREES MURRAY GELL-MANN (1929–)



304 MURRAY GELL-MANN IN CONTEXT U nderstanding of the How can it be that structure of the atom writing down a few simple BRANCH has changed dramatically and elegant formulae can Physics since the end of the 19th century. predict universal regularities In 1897, J. J. Thomson made the BEFORE bold suggestion that cathode rays of Nature? 1932 A new particle, the are streams of particles far smaller Murray Gell-Mann neutron, is discovered by than the atom; he had discovered James Chadwick. There are the electron. In 1905, building energies, and hence with greater now three known subatomic on the light quanta theory of Max masses according to Einstein’s particles with mass: the Planck, Albert Einstein suggested principle of mass–energy proton, neutron, and electron. that light should be thought of as a equivalence (E = mc2). stream of tiny massless particles, 1932 The first antiparticle, which we now call photons. In Seeking to explain the nature the positron, is discovered. 1911, Thomson’s protégé Ernest of interactions inside the atomic Rutherford deduced that an atom’s nucleus, scientists in the 1950s 1940s–50s Increasingly nucleus is small and dense, with and 1960s produced an enormous powerful particle accelerators— electrons in orbit around it. The body of work providing the which smash particles image of an atom as an indivisible conceptual framework for all matter together at high speeds— whole had been destroyed. in the universe. Many figures produce large numbers of contributed to this process, but new subatomic particles. In 1920, Rutherford named the American physicist Murray nucleus of the lightest element, Gell-Mann played a pivotal role in AFTER hydrogen, the proton. Twelve years the construction of a taxonomy of 1964 The discovery of the later, the neutron was discovered, fundamental particles and force- omega (Ω–) particle confirms and a more complex picture of carriers called the standard model. the quark model. nuclei made of protons and neutrons emerged. Then, in the 2012 The Higgs boson is 1930s, a glimpse of further realms discovered at CERN, adding of particles came from studies of weight to the standard model. cosmic rays—high-energy particles that are thought to originate in supernovae. The studies revealed new particles associated with high Formulating the standard The particle zoo model of particle physics leads theorists to Gell-Mann jokes that the goals of predict that hadrons (protons and neutrons) the theoretical elementary particle physicist are “modest”—they are made of smaller particles merely aim to explain the called quarks. “fundamental laws that govern all matter in the universe.” Theorists, Quarks group Quarks are he says, “work with pencil, paper, together in twos detected by colliding and wastebasket, and the most protons in a particle important of those is the last.” and threes to By contrast, the experimentalist’s make hadrons. accelerator. principal tool is the particle accelerator, or collider. In 1932, the first atomic nuclei— of the element lithium—were blown apart by physicists Ernest Walton

FUNDAMENTAL BUILDING BLOCKS 305 See also: Max Planck 202–05 ■ Ernest Rutherford 206–13 ■ Albert Einstein 214–21 ■ Paul Dirac 246–47 ■ Richard Feynman 272–73 ■ Sheldon Glashow 292–93 ■ Peter Higgs 298–99 and John Cockcroft using Collisions between subatomic and then sifting through the a particle accelerator in Cambridge, particles splinter them into their wrecked pieces in an attempt to England. Since then, ever more core units. The energy released is find out how the timepiece works. powerful particle accelerators have sometimes enough to produce new been constructed. These machines generations of particles that cannot By 1953, with colliders boost tiny subatomic particles to exist under everyday conditions. achieving ever-increasing energies, nearly the speed of light before Showers of short-lived, exotic exotic particles not found in slamming them into targets or particles spray off these pileups, ordinary matter seemed to tumble each other. Research is now driven before swiftly annihilating or out of thin air. More than 100 by theoretical predictions—the decaying. With ever-increasing strongly interacting particles were largest particle accelerator, the energies at their disposal, detected, all thought at the time ❯❯ Large Hadron Collider (LHC) in researchers attempt to probe the Switzerland, was built primarily to mysteries of matter by getting The Stanford Linear Accelerator find the theoretical Higgs boson even closer to the conditions at the in California, built in 1962, is 2 miles (pp.298–99). The LHC is a 17-mile birth of matter itself—the Big Bang. (3 km) long—the longest linear (27-km) ring of superconducting The process has been likened to accelerator in the world. It was here, magnets that took 10 years to build. smashing two watches together in 1968, that it was first demonstrated that protons are composed of quarks.

306 MURRAY GELL-MANN to be fundamental. This merry “hadrons,” which include the Three quarks for Muster Mark! circus of new species was proton and neutron, are “strongly James Joyce dubbed the “particle zoo.” interacting” and influenced by all four fundamental forces, while the most economical design, he The Eightfold Way lightweight “leptons,” such as proposed that hadrons contained By the 1960s, scientists had the electron and neutrino, are a new and as-yet-unseen grouped particles according to unaffected by the strong force. fundamental subunit. Since the how they were affected by the heavier particles were no longer four fundamental forces: gravity, Gell-Mann made sense of the fundamental, this change reduced electromagnetic force, and the particle zoo with an octet ordering the number of fundamental weak and strong nuclear forces. system he called the “Eightfold particles down to a manageable All particles with mass are Way,” a pun on the Buddhist Noble number—hadrons were now simply influenced by gravity. The Eightfold Path. Just as Mendeleev combinations of multiple electromagnetic force acts on any had done when arranging the elementary components. Gell- particle with an electric charge. chemical elements into a periodic Mann, with his penchant for wacky The weak and strong forces table, Gell-Mann imagined a names dubbed this particle a operate over the miniscule ranges chart into which he placed the “quark” (pronounced “kwork”), after found within the atomic nucleus. elementary particles, leaving a favorite line from James Joyce’s Heavyweight particles called spaces for as yet undiscovered novel Finnegans Wake. pieces. In an effort to make the Real or not real? Fermions Bosons Gell-Mann was not the only person to suggest this idea. In 1964, a ≈2.3 MeV/c² ≈1.275 GeV/c² ≈173.07 GeV/c² 0 ≈126 GeV/c² student at Caltech, Georg Zweig, had suggested that hadrons were U C t g H made of four basic parts, which he called “aces.” The CERN journal up charm top gluon Higgs Physics Letters refused Zweig’s boson paper, but that same year published 0 a paper by the more senior Gell- ≈4.8 MeV/c² ≈95 MeV/c² ≈4.18 GeV/c² Mann outlining the same idea. ������ d s b Gell-Mann’s paper may have photon been published because he did down strange bottom not suggest that there was any underlying reality to the pattern— 0.511 MeV/c² 105.7 MeV/c² 1.777 GeV/c² 91.2 GeV/c² he was simply proposing an organizing design. However, this e ������ ������ Z design appeared unsatisfactory, since it required quarks to have electron muon tau Z boson fractional charges, such as –1/3 and +2/3. These were nonsensical to <2.2 eV/c² <0.17 MeV/c² <15.5 MeV/c² 80.4 GeV/c² ������e ������������ ������������ W electron muon tau W boson neutrino neutrino neutrino The standard model ≈2.3 MeV/c² Mass Quarks arranges the fundamental Symbol Gauge bosons particles in a table according U Name Leptons to their properties. The Higgs up Higgs boson boson, predicted by the model, was discovered in 2012.

FUNDAMENTAL BUILDING BLOCKS 307 accepted theory, which only “color charge,” which allows them to Murray Gell-Mann allowed for whole-number charges. interact via the strong force. The Gell-Mann realized that if these leptons do not carry color charge and Born in Manhattan, Murray subunits remained hidden, trapped are not affected by the strong force. Gell-Mann was a child inside hadrons, this didn’t matter. There are six leptons—the electron, prodigy. He taught himself The predicted omega particle (Ω–), muon, tau, and the electron, muon, calculus at 7 years old and made up of three quarks, was and tau neutrinos. Neutrinos have no entered Yale at 15. He earned detected at Brookhaven National electrical charge and only interact a doctoral degree from the Laboratory, New York, soon after via the weak force, making them Massachusetts Institute of Gell-Mann’s publication. This extremely hard to detect. Each Technology (MIT), graduating confirmed the new model, which particle also has a corresponding in 1951, and then decamped Gell-Mann has insisted should be “antiparticle” of antimatter. to the California Institute of credited both to him and to Zweig. Technology (Caltech), where The standard model explains he worked with Richard Initially, Gell-Mann was forces at the subatomic level as Feynman to develop a doubtful that quarks could ever the result of an exchange of force- quantum number called be isolated. However, he now carrying particles known as “strangeness.” Japanese emphasizes that although he “gauge bosons.” Each force has physicist Kazuhiko Nishijima initially saw his quarks as its own gauge boson: the weak had made the same discovery, mathematical entities, he never force is mediated by the W+, but called it “eta-charge.” ruled out the possibility that quarks W–, and Z bosons; the strong might be real. Experiments at the electromagnetic force by photons; With wide-ranging Stanford Linear Accelerator Center and the strong force by gluons. interests and speaking some (SLAC) between 1967 and 1973 13 languages fluently, Gell- scattered electrons off hard The standard model is a robust Mann enjoys displaying his granular particles within the theory and has been verified by polymath’s breadth of proton, revealing the reality of experiment, notably with the knowledge with plays on quarks in the process. discovery of a Higgs boson—the words and arcane references. particle that gives other particles He is perhaps the originator The standard model mass—at CERN in 2012. However, of the trend for giving new The standard model developed from many consider the model inelegant particles funny names. His Gell-Mann’s quark model. In this and there are problems with it, discovery of the quark won model, particles are divided into such as its failure to incorporate him the 1969 Nobel Prize. fermions and bosons. Fermions are dark matter or explain gravity in the building blocks of matter, while terms of boson interaction. Other Key works bosons are force-carrying particles. questions that remain unanswered are why there is a preponderance 1962 Prediction of the The fermions are further split of matter (rather than antimatter) in Ω– Particle into two families of elementary the universe, and why there appear 1964 The Eightfold Way: particles—quarks and leptons. to be three generations of matter. ■ A Theory of Strong Quarks group together in twos and Interaction Symmetry threes to make up the composite Our work is a delightful game. particles called hadrons. Subatomic Murray Gell-Mann particles with three quarks are known as baryons, and include protons and neutrons. Those made of a quark and antiquark pair are called mesons, and include pions and kaons. In total there are six quark “flavors”—up, down, strange, charm, top, and bottom. The defining characteristic of quarks is that they carry something called

A THEORY OF EVERYTHING? GABRIELE VENEZIANO (1942–)



310 GABRIELE VENEZIANO String theory treats particles as vibrating strings of energy. IN CONTEXT Adding hidden dimensions and BRANCH “supersymmetric” particles produces Physics superstring theory. BEFORE 1940s Richard Feynman Superstring theory Superstring theory and other physicists develop gives rise to may explain the interaction quantum electrodynamics (QED), which describes multidimensional of the four fundamental quantum-level interactions due branes. forces in the universe. to the electromagnetic force. The Big Bang may String theory is 1960s The standard model of be the result of two a possible candidate particle physics reveals the full branes colliding. range of subatomic particles for a “Theory of known so far and the Everything.” interactions that affect them. AFTER 1970s String theory falls out of favor temporarily as quantum chromodynamics appears to offer a better explanation of the strong nuclear force. 1980s Lee Smolin and Italian Carlo Rovelli develop the theory of loop quantum gravity, which removes the need to theorize hidden extra dimensions. P ut simply, string theory is The development of string theory hadrons, the composite particles the remarkable—and still has had a long and bumpy road, that are subject to the influence of controversial—idea that all and it is still not accepted by many the strong force. matter in the universe is made up physicists. But work on the theory not of pointlike particles, but of tiny continues—not least because it is In 1960, as part of an ongoing “strings” of energy. The theory lays currently the only theory trying to study of the properties of hadrons, out a structure that we cannot unite the “quantum gauge” theories American physicist Geoffrey detect, but that explains all the of the electromagnetic, weak, Chew proposed a radical new phenomena that we see. Waves of and strong nuclear forces with approach—abandoning the vibration within these strings give Einstein’s theory of gravity. preconception that hadrons were rise to the quantized behaviors particles in the traditional sense, (discrete properties such as electric Explaining the strong force and modeling their interactions charge and spin) that are found in String theory began life as a model in terms of a mathematical object nature, and mirror the harmonics to explain the strong force that called an S-matrix. When Italian that can be produced, for example, binds together the particles in the physicist Gabriele Veneziano by plucking a violin string. nuclei of atoms, and the behavior of investigated the results of Chew’s model, he found patterns

FUNDAMENTAL BUILDING BLOCKS 311 See also: Albert Einstein 214–21 ■ Erwin Schrödinger 226–33 ■ Georges Lemaître 242–45 ■ Paul Dirac 246–47 ■ Richard Feynman 272–73 ■ Hugh Everett III 284–85 ■ Sheldon Glashow 292–93 ■ Murray Gell-Mann 302–07 suggesting that particles would According to One final complication was that appear at points along straight string theory, the theory could not properly work one-dimensional lines—the first the quantized without assuming the existence hint of what we now call strings. properties we of no fewer than 26 separate In the 1970s, physicists continued observe arise dimensions (instead of the usual to map these strings and their when a string four—three dimensions of space, behavior, but their work began takes on different plus time). The concept of extra to bring up annoyingly complex vibrational dimensions had been around for a and counterintuitive results. For states, similar long time: German mathematician example, particles have a property to the harmonic Theodor Kaluza had attempted called spin (analogous to angular notes played on to unify electromagnetism and momentum), which can only take a violin. gravity through the use of an extra (fifth) dimension. This was not a certain values. The initial drafts problem mathematically, but did of string theory could produce pose the question as to why we bosons (particles with zero or do not experience all dimensions. whole-number spins, typically In 1926, Swedish physicist Oscar the “messenger” particles in Klein explained how such extra models of quantum forces), but dimensions might remain invisible not fermions (particles with half- on everyday macroscopic scales integer spins, including all matter by suggesting they might “roll up” particles). The theory also predicted into quantum-scale loops. the existence of particles that move faster than the speed of light, thus String theory suffered a fall from traveling backward in time. grace in the mid-1970s. The theory of quantum chromodynamics (QCD), which introduced the concept of “color charge” for quarks to explain their interaction via the strong nuclear force, offered a much better description. But ❯❯ String theory is an attempt Gabriele Veneziano From 1976 onward, Veneziano at a deeper description of worked mainly at CERN’s nature by thinking of an Born in Florence, Italy, in 1942, Theory Division in Geneva, elementary particle not as Gabriele Veneziano studied rising to become its director a little point but as a little in his home city before obtaining between 1994 and 1997. loop of vibrating string. his PhD from Israel’s Weizmann Since 1991, he has focused on Institute of Science, where he investigating how string theory Edward Witten returned in 1972 as professor and QCD can help to describe of physics following some time the hot, dense conditions just at the European particle physics after the Big Bang. laboratory CERN. While at the Massachusetts Institute of Key work Technology (MIT) in 1968, he hit upon string theory as a 1968 Construction of a model for describing the strong Cross-Symmetric, Regge- nuclear force, and began to behaved Amplitude for pioneer research into the topic. Linearly Rising Trajectories

312 GABRIELE VENEZIANO even before this, some scientists describe them would be reduced to String theory envisions a had been murmuring that the ten. The fact that these additional multiverse in which our theory was conceptually flawed. particles remain undetected might universe is one slice of bread The more work they did, the more it be due to the fact that they are only in a big cosmic loaf. The seemed as though strings were not capable of independent existence describing the strong force at all. at energies far above those other slices would be produced in even the most powerful displaced from ours in some The rise of superstrings modern particle accelerators. Groups of physicists continued extra dimension of space. to work on string theory, but they This revised “supersymmetric Brian Greene needed to find solutions to some string theory” soon became known of its problems before the wider more simply as “superstring M-theory scientific community would take theory.” However, major issues In 1995, US physicist Edward it seriously again. A breakthrough remained—particularly the fact Witten presented a new model came in the early 1980s with the that five rival interpretations known as M-theory, which offered idea of supersymmetry. This of superstrings emerged. a solution to the problem of is the suggestion that each of Evidence also began to mount competing superstring theories. the known particles found in the that superstrings should give rise He added a single additional standard model of particle physics not only to 2-dimensional strings dimension, bringing the total (pp.302–05) has an undiscovered and 1-dimensional points, but also up to 11, and this allowed all five “superpartner”—a fermion to to multidimensional structures, superstring approaches to be match every boson, and a boson collectively known as “branes.” described as aspects of a single to match every fermion. If this Branes can be thought of as theory. The 11 dimensions of were the case, then many of the analogous to 2-dimensional space-time required by M-theory outstanding problems with strings membranes moving in our mirrored the 11 dimensions would promptly vanish, and the 3-dimensional world: similarly, required by then-popular models number of dimensions required to a 3-dimensional brane could of “supergravity” (supersymmetric move in a 4-dimensional space. gravity). According to Witten’s theory, the seven additional Superstring theory predicts dimensions of space required the existence of multidimensional would be “compactified”—curled branes. Our universe might be one up into tiny structures analogous to such brane. It is suggested that spheres that would effectively act a Big Bang event occurs when and appear as points on all but the two branes collide, producing most microscopic of scales. a “cyclic universe” model. The major problem of M-theory, 4. Ripples form in the branes. however, is that the detail of the theory itself is currently unknown. 1. Branes collide 3. The branes Rather, it is a prediction of the producing a expand to existence of a theory with certain Big Bang. become flat characteristics that would neatly and empty. fulfill a number of observed or predicted criteria. 2. One brane develops into our universe today.

FUNDAMENTAL BUILDING BLOCKS 313 Despite its current limitations, M-theory has proved a huge inspiration to various fields of physics and cosmology. Black hole singularities can be interpreted as string phenomena, as can the early stages of the Big Bang. One intriguing upshot of M-theory is the “cyclic universe” model proposed by cosmologists such as Neil Turok and Paul Steinhardt. In this theory, our universe is just one of many separate branes separated from each other by minute distances in 11-dimensional space-time, and drifting minutely in relation to one another on trillion-year time scales. Collisions between branes, it has been argued, could result in huge releases of energy and trigger new Big Bangs. Theories of everything in nature from the other three This is a 2-dimensional slice of a M-theory has been proposed as a forces. These three forces all act 6-dimensional mathematical structure possible “Theory of Everything”— between individual particles but called a Calabi-Yau manifold. It is a means of uniting the quantum only on relatively small scales, suggested that string theory’s six field theories that successfully while gravity is insignificant except hidden dimensions may take this form. describe electromagnetism and when huge numbers of particles the weak and strong nuclear forces conglomerate, but acts across quantized properties of particles with the description of gravity enormous distances. One possible arise not from their stringlike provided by Einstein’s general explanation of gravity’s unusual nature, but rather from the small- theory of relativity. Hitherto, a behavior is that its influence at the scale structure of space-time itself, quantum description of gravitation quantum level may “leak out” which is quantized into tiny loops. has remained elusive. Gravity into the higher dimensions, so that LQG and its various developments appears to be radically different only a small fraction is perceived offer several intriguing advantages within the familiar dimensions of over string theory, removing the If string theory is a mistake, our universe. need for additional dimensions, and it’s not a trivial mistake. It’s a it has been applied successfully deep mistake and therefore String theory is not the to several major cosmological only candidate for a Theory of problems. However, the case for kind of worthy. Everything. Loop quantum gravity either string particles or looped Lee Smolin (LQG) was developed by Lee space-time as the “Theory of Smolin and Carlo Rovelli from Everything” remains inconclusive. ■ the late 1980s. In this theory, the

314 BLACK HOLES EVAPORATE STEPHEN HAWKING (1942–) IN CONTEXT I n the 1960s, British physicist Around 1973, Hawking became Stephen Hawking was one interested in quantum mechanics BRANCH among several brilliant and the behavior of gravity on a Cosmology researchers who became interested subatomic scale. He made an in the behavior of black holes. important discovery—that despite BEFORE He wrote his doctoral thesis their name, black holes do not just 1783 John Michell theorizes on the cosmological aspects swallow up matter and energy but objects whose gravity is so of a singularity (the point in emit radiation. So-called Hawking great that they trap light. space-time at which all of a black radiation is emitted at the black hole’s mass is concentrated), hole’s event horizon—the outer 1930 Subrahmanyan and drew parallels between the boundary at which the black hole’s Chandrasekhar proposes singularities of stellar-mass black gravity becomes so strong that not that a collapsing stellar core holes and the initial state of the even light can escape. Hawking above a certain mass would universe during the Big Bang. showed that in the case of a give rise to a black hole. rotating black hole, the intense My goal is simple. It is a gravity would give rise to the 1971 The first likely black hole complete understanding of the production of virtual, subatomic is identified—Cygnus X-1. universe, why it is as it is and particle-antiparticle pairs. On the event horizon, it would be possible AFTER why it exists at all. for one element of each pair to 2002 Observations of stars Stephen Hawking be pulled into the black hole, orbiting close to the center effectively boosting the survivor of our galaxy suggest the into a sustained existence as a real presence of a giant black hole. particle. The result of this to a distant observer is that the event 2012 American string theorist horizon emits low-temperature Joseph Polchinski suggests thermal radiation. Over time, that quantum entanglement the energy carried away by this produces a super-hot “firewall” radiation causes the black hole to at a black hole’s event horizon. lose mass and evaporate away. ■ 2014 Hawking announces See also: John Michell 88–89 ■ Albert Einstein 214–21 ■ that he no longer thinks Subrahmanyan Chandrasekhar 248 black holes can exist.

FUNDAMENTAL BUILDING BLOCKS 315 EARTH AND ALL ITS LIFE FORMS MAKE UP A SINGLE LIVING ORGANISM CALLED GAIA JAMES LOVELOCK (1919–) IN CONTEXT D uring the early 1960s, Evolution is a tightly coupled a team was assembled dance, with life and the BRANCH by NASA in Pasadena, material environment as Biology California, to think about how partners. From the dance to look for life on Mars. British emerges the entity Gaia. BEFORE environmental scientist James James Lovelock 1805 Alexander von Humboldt Lovelock was asked how he would declares that nature can be tackle the problem, which prompted The Gaia hypothesis represented as one whole. him to think about life on Earth. Lovelock suggested that the entire planet makes up a single, 1859 Charles Darwin argues Lovelock soon discovered a self-regulating, living entity, that life forms are shaped by range of necessary features for life. which he called Gaia. The very their environment. All life on Earth depends on water. presence of life itself regulates The average surface temperature the temperature of the surface, the 1866 German naturalist must stay within 50–60°F (10–16°C) concentration of oxygen, and Ernst Haeckel coins the for enough liquid water to be the chemical composition of the term ecology. present, and it has remained within oceans, optimizing conditions this range for 3.5 million years. for life. However, he warned that 1935 British botanist Arthur Cells require a constant level of human impact on the environment Tansley describes Earth’s life salinity and generally cannot may disrupt this delicate balance. ■ forms, landscape, and climate survive levels above 5 percent, and as a giant ecosystem. ocean salinity has remained at about 3.4 percent. Since oxygen AFTER first appeared in the atmosphere, 1970s Lynn Margulis about two billion years ago, its describes the symbiotic concentration has remained close relationship of microbes and to 20 percent. If it were to drop Earth’s atmosphere; she later below 16 percent, there would defines Gaia as a series of not be enough to breathe—if it interacting ecosystems. rose to 25 percent, forest fires would never go out. 1997 The Kyoto Protocol sets targets for the reduction See also: Alexander von Humboldt 130–35 ■ Charles Darwin 142–49 ■ of greenhouse gases. Charles Keeling 294–95 ■ Lynn Margulis 300–01

316 A CLOUD IS MADE OF BILLOWS UPON BILLOWS BENOÎT MANDELBROT (1924–2010) IN CONTEXT Belgian mathematician Benoît Mandelbrot used computers BRANCH to model the patterns in Mathematics nature in the 1970s. In doing so, he launched a new field of mathematics BEFORE —fractal geometry—which has 1917–20 In France, Pierre since found uses in many fields. Fatou and Gaston Julia build mathematical sets using Fractional dimensions The Mandlebrot set is a fractal complex numbers—that is, Whereas conventional geometry generated using a set of complex combinations of real and uses whole-number dimensions, numbers, and conceals limitless imaginary numbers (multiples fractal geometry employs fractional representations of itself at every scale. of the square root of –1). The dimensions, which can be thought When visualized graphically, it produces resulting sets are either of as a “roughness measure.” To the distinctive shape shown here. “regular” (Fatou sets) or understand what this means, think “chaotic” (Julia sets) and are of measuring Britain’s coastline close they are to us without the precursors of fractals. with a stick. The longer the stick, external clues—clouds look the the shorter the measurement, as same from all distances. Our 1926 British mathematician it will smooth out any roughness bodies contain many examples and meteorologist Lewis Fry along its length. The British coast of fractals, such as the way the Richardson publishes Does has a fractional dimension of 1.28, lungs branch out to fill space the Wind Possess a Velocity, which is an index of how much the efficiently. Like chaotic functions, pioneering mathematical measurement increases as the fractals show sensitivity to small models for chaotic systems. length of the stick decreases. changes in initial conditions, and they are used to analyze chaotic AFTER A characteristic of fractals is systems such as the weather. ■ Present-day Fractals form self-similarity—meaning that there part of the field of complexity is an equal amount of detail at all science. They are used in scales of magnification. The fractal marine biology, earthquake nature of clouds, for example, modeling, population studies, makes it impossible to tell how and oil and fluid mechanics. See also: Robert FitzRoy 150–55 ■ Edward Lorenz 296–97

FUNDAMENTAL BUILDING BLOCKS 317 A OUANTUM MODEL OF COMPUTING YURI MANIN (1937–) IN CONTEXT Q uantum information made of “trapped” subatomic processing is one of the particles, and also has two possible BRANCH newest fields in quantum states. An electron, for example, Computer science mechanics. It operates in a can be spin-up or spin-down, and fundamentally different way from photons of light can be polarized BEFORE conventional computing. The horizontally or vertically. However, 1935 Albert Einstein, Boris Russian-German mathematician the quantum mechanical wave Podolsky, and Nathan Rosen Yuri Manin was among the very function allows qubits to develop the “EPR paradox,” first pioneers developing the theory. exist in a superposition of both providing the first description states, increasing the amount of of quantum entanglement. The bit is the fundamental information that they can carry. carrier of information in a Quantum theory also permits AFTER computer, and can exist in two qubits to become “entangled,” 1994 American mathematician states: 0 and 1. The fundamental which exponentially increases the Peter Shor develops an unit of information in quantum data carried with each additional algorithm that can achieve computing is called a qubit. It is qubit. This parallel processing the factorization of numbers could theoretically produce using quantum computers. 0 extraordinary computing power. 1998 Using Hugh Everett’s 1 Demonstrating the theory many-worlds interpretation of First aired in the 1980s, quantum quantum mechanics, theorists The information on a qubit can computers seemed just theoretical. imagine a superposition state be represented as any point on the However, calculations have recently in which a quantum computer surface of a sphere—a 0, a 1, or a been achieved on arrays with only is both on and off. superposition of the two. a few qubits. To provide a useful machine, quantum computers must 2011 A research team from achieve hundreds or thousands of the University of Science entangled qubits, and there are and Technology in Hefei, problems scaling up to this size. China, correctly finds the Work on these problems continues. ■ prime factors of 143 using a quantum array of four qubits. See also: Albert Einstein 214–21 ■ Erwin Schrödinger 226–33 ■ Alan Turing 252–53 ■ Hugh Everett III 284–85

318 GENES CAN MOVE FROM SPECIES TO SPECIES MICHAEL SYVANEN (1943–) IN CONTEXT Heat-killed bacteria This happens because can transfer their genes can move between BRANCH Biology characteristics bacterial cells. to living bacteria. BEFORE 1928 Frederick Griffith shows Genes can Similar genes that one strain of bacteria can move from species have been identified be transformed into another, in distantly related by the transfer of what is later to species. species of organisms, found to be DNA. including vertebrates. 1946 Joshua Lederberg and T he continuity of life—the Back in 1928, British physician Edward Tatum discover the growth, reproduction, and Frederick Griffith was studying the natural exchange of genetic evolution of organisms—is bacteria implicated in pneumonia. material in bacteria. widely seen as a vertical process, He found that a harmless strain driven by genes passed down from could be made dangerous simply 1959 Tomoichiro Akiba and parents to offspring. But in 1985, by mixing its living cells with the Kunitaro Ochia report that American microbiologist Michael dead remnants of a heat-killed antibiotic-resistant plasmids Syvanen proposed that, rather than virulent one. He attributed his (rings of DNA) can move being simply passed down, genes results to a transforming “chemical between bacteria. could also be passed horizontally principle” that had leaked from the between species, independently dead cells into the living ones. A AFTER of reproduction, and that horizontal quarter of a century before DNA’s 1993 American geneticist gene transfer (HGT) plays a key structure was unlocked by James Margaret Kidwell identifies role in evolution. Watson and Francis Crick, Griffith instances where genes have crossed species boundaries in complex organisms. 2008 American biologist John K. Pace and others present evidence of horizontal gene transfer in vertebrates.

FUNDAMENTAL BUILDING BLOCKS 319 See also: Charles Darwin 142–49 ■ Thomas Hunt Morgan 224–25 ■ James Watson and Francis Crick 276–83 ■ William French Anderson 322–23 The flow of genes This sort of horizontal gene transfer occur in not only microbes but also between different species can also happen via viruses, as more complex organisms, in both Lederberg’s student Norton Zinder plants and animals. Darwin’s tree represents a form of discovered. Viruses are even of life may look more like a net, genetic variation whose smaller than bacteria and can with multiple ancestors rather than implications have not been invade living cells—including a last universal common ancestor. bacteria. They may interfere with With potential implications for fully appreciated. the host genes, and when they taxonomy, disease and pest control, Michael Syvanen move from host to host, they may and genetic engineering, HGT’s full take host genes with them. significance is still unfolding. ■ had found the first evidence that DNA could pass horizontally Genes for development DNA plasmids, colored blue in between cells of the same From the mid-1980s, Syvanen set this micrograph, are independent of generation, as well as vertically HGT in a wider context. He noted a cell’s chromosomes, yet they can between generations. similarities in how the development replicate genes and be used to insert of embryos is genetically controlled new genes into organisms. In 1946, American biologists at a cellular level—even between Joshua Lederberg and Edward distantly related species—and his theory of horizontal gene Tatum demonstrated that bacteria attributed this to genes moving transfer (HGT) and its role in exchange genetic material as part between different organisms in adaptation and evolution. of their natural behavior. In 1959, evolutionary history. He argued a team of Japanese microbiologists that the genetic control of animal Since 1987, Syvanen has led by Tomoichiro Akiba and development had evolved to be been professor of medical Kunitaro Ochia showed that this similar in different groups because microbiology and immunology kind of DNA transfer explains how this maximized the chances that at the School of Medicine in the resistance to antibiotics can spread gene-swapping would work. University of California at Davis. through bacteria so quickly. As genome sequences are Key works Transforming microbes completed for more species, and Bacteria have small, mobile rings as the fossil record is reexamined, 1985 Cross-species Gene of DNA called plasmids that pass evidence suggests that HGT may Transfer: Implications for a from cell to cell when they come New Theory of Evolution into direct contact—taking their Michael Syvanen 1994 Horizontal Gene Transfer: genes with them. Some bacteria Evidence and Possible contain genes that make them Michael Syvanen trained in Consequences resist the action of certain types of chemistry and biochemistry at antibiotics. The genes are copied the University of Washington whenever the DNA replicates, and and the University of California can spread through a population of at Berkeley before going on bacteria as the DNA is transferred. to specialize in the field of microbiology. He was appointed professor of microbiology and molecular genetics at Harvard Medical School in 1975, where he conducted research in the development of antibiotic resistance in bacteria, and insecticide resistance in flies. His findings led him to publish

320 THE SOCCER BALL CAN WITHSTAND A LOT OF PRESSURE HARRY KROTO (1939–) IN CONTEXT We’ve made a molecule that is so tough and resilient that… BRANCH …it has multiple applications in many fields of technology Chemistry and medicine. BEFORE It is shaped like a soccer ball. 1966 British chemist David Jones predicts the The soccer ball can withstand a lot of pressure. creation of hollow carbon molecules. F or more than two centuries, with a laser beam to produce scientists thought that various carbon clusters, forming 1970 Scientists in Japan elemental carbon (C) molecules with an even number of and Britain independently existed in only three forms, or carbon atoms. The most abundant predict the existence of the allotropes: diamond, graphite, clusters had the formulae C60 and carbon-60 (C60) molecule. and amorphous carbon—the main C70. These were molecules that had constituent of soot and charcoal. never been seen before. AFTER That changed in 1985 with the 1988 C60 is found in soot work of British chemist Harry Kroto C60 (or carbon-60) soon turned from candles. and his American colleagues out to have remarkable properties. Robert Curl and Richard Smalley. The chemists realized that it had 1993 German physicist The chemists vaporized graphite a structure like a soccer ball—a Wolfgang Krätschmer and complete spherical cage of carbon American physicist Don Huffman develop a method for synthesizing “fullerenes.” 1999 Austrian physicists Markus Arndt and Anton Zeilinger demonstrate that C60 has wavelike properties. 2010 The spectrum of C60 is seen in cosmic dust 6,500 light years from Earth.

FUNDAMENTAL BUILDING BLOCKS 321 See also: August Kekulé 160–65 ■ Linus Pauling 254–59 atoms, each bonded to three others products (chemical substances) Harry Kroto in such a way that all the faces of whose properties are still the polyhedron are either pentagons being studied. Harold Walter Krotoschiner or hexagons. C70 is more like a was born in Cambridgeshire, football; it has an extra ring of The new world of nano England, in 1939. Fascinated carbon atoms around its equator. Although C60 was the first of these by the toy building set molecules to be studied, its Meccano, he chose to study Both C70 and C60 reminded discovery has led to an entire new chemistry, and became a Kroto of the futuristic geodesic branch of chemistry—the study professor at Sussex University domes designed by American of fullerenes. Nanotubes have been in 1975. He was interested in architect Buckminster Fuller, made—cylindrical fullerenes, only looking into space for so he named the compounds a few nanometers wide, but up to compounds with multiple buckminsterfullerene, but they are several millimeters long. They carbon-carbon bonds, such as also called buckyballs, or fullerenes. are good conductors of heat and H-C≡C-C≡C-C≡N, and found electricity, chemically inactive, and evidence using spectroscopy Properties of buckeyballs enormously strong, which makes (studying the interaction The team found that the C60 them hugely useful for engineering. between matter and radiated compound was stable and could energy). When he heard of the be heated to high temperatures There are many others that laser spectroscopy work of without decomposing. It turned are being studied for everything Richard Smalley and Robert into a gas at about 1,202° F (650° C). from electrical properties to Curl at Rice University, he It was odorless, and was insoluble medical treatments for cancer to joined them in Texas, and in water, but slightly soluble in HIV. The latest spin-off from the together they discovered C60. organic solvents. The buckyball is fullerenes is graphene, a flat sheet Since 2004, Kroto has worked also one of the largest objects ever of carbon atoms, like a single layer on nanotechnology at Florida found to exhibit the properties of graphite. This substance has State University. both of a particle and of a wave. remarkable properties that are In 1999, Austrian researchers sent being hotly studied. ■ In 1995, he set up the molecules of C60 through narrow Vega Science Trust to make slits and observed the interference Each carbon atom of a C60 molecule science movies for education pattern of wavelike behavior. bonds to three others. The molecule and training. They are freely has 32 faces in total, 12 of which are available on the Internet at Solid C60 is as soft as graphite, pentagons and 20 hexagons, forming www.vega.org.uk. but when highly compressed, it a distinctive, soccer-ball shape. changes into a superhard form of Key works diamond. The soccer ball, it seems, can withstand a lot of pressure. 1981 The Spectra of Interstellar Molecules Pure C60 is a semiconductor 1985 60:Buckminsterfullerene of electricity, meaning that its (with Heath, O’Brien, Curl, conductivity is between that of and Smalley) an insulator and a conductor. But when atoms of alkali metals such as sodium or potassium are added to it, it becomes a conductor, and even a superconductor at low temperatures, conducting electricity with no resistance at all. C60 also undergoes a wide variety of chemical reactions, resulting in huge numbers of

322 INSERT GENES INTO HUMANS TO CURE DISEASE WILLIAM FRENCH ANDERSON (1936–) IN CONTEXT Many diseases are T he human genome—the inherited and are caused entirety of a human’s BRANCH hereditary information— Biology by defective genes. consists of about 20,000 genes. A gene is a living organism’s BEFORE Functional genes molecular unit of heredity. 1984 US researcher Richard can be isolated from However, genes often malfunction. Mulligan uses a virus as a tool normal cells using enzymes A defective gene is made when a for inserting genes into cells normal gene is not copied properly, taken from mice. that cut DNA. and the “error” is passed down from parents to offspring. The symptoms 1985 William French Genes can be that arise from these so-called Anderson and Michael Blaese transferred between genetic diseases depend upon show this technique can be cells by using vectors: the gene involved. A gene works used to correct defective cells. viruses or rings of DNA by controlling the production of a protein—one of many that perform 1989 Anderson performs the called plasmids. a vast variety of functions in living first safety test in human gene organisms—but this production therapy, injecting a harmless Genes can be inserted fails if there is an error. For marker into a 52-year-old man. into humans to example, if a blood-clotting gene He performs the first clinical cure disease. malfunctions, the body stops trial a year later. producing the blood protein that makes blood clot—causing the AFTER disease hemophilia. 1993 UK researchers describe the results of successful Genetic diseases cannot be animal experiments providing cured by conventional drugs, and gene therapy treatment of for a long time, it was only possible cystic fibrosis. to alleviate the symptoms and make a sufferer’s life as comfortable 2012 The first multidose trial as possible. But in the 1970s, of cystic fibrosis gene therapy scientists began considering the on humans begins. possibility of “gene therapy” to cure disease—using “healthy” genes to replace or override faulty ones.

FUNDAMENTAL BUILDING BLOCKS 323 See also: Gregor Mendel 166–71 ■ Thomas Hunt Morgan 224–25 ■ Craig Venter 324–25 ■ Ian Wilmut 326 1. Cells containing the 2. A virus is deficiency condition, known as defective gene are taken modified so that it bubble-boy disease. Sufferers of cannot reproduce. this condition are so susceptible from the body. to infection that they may have to spend their whole lives in a sterile 6. The healthy cells 3. The healthy environment, or “bubble.” are injected into the gene is Anderson’s team took sample body, where they inserted into cells from the two girls, treated work normally. the virus. them with the gene-carrying virus, then transfused the cells back 5. The cells are 4. The virus is mixed into the girls. The treatment was genetically altered with cells from repeated several times over two the body. years—and it worked. However, by the virus. its effects were only temporary, Scientists use viruses as a since new cells made by vector to introduce healthy the body would still inherit the genes into a patient’s cells. malfunctioning gene. This remains a central problem for Introducing new genes normally associated with causing gene therapy researchers today. Genes can be introduced into disease, rather than fighting it. diseased parts of the body by a Viruses naturally invade living Future prospects vector—a particle that “carries” the cells as part of their infection Remarkable breakthroughs have gene to its source. Researchers cycle, but could they perhaps carry been made in the treatment of other investigated several possibilities for the therapeutic genes with them? conditions. In 1989, scientists entities that might act as a vector— working in the US identified the including viruses, which are more In the 1980s, a team of gene that causes cystic fibrosis. American scientists including In this condition, defective cells Gene therapy is ethical William French Anderson produce sticky mucus that clogs because it can be supported succeeded in using viruses lungs and the digestive system. to insert genes into cultured Within five years of identifying by the fundamental moral (laboratory-grown) tissue. They the defective gene responsible, principle of beneficence: it tested it on animals that suffered a technique had been developed would relieve human suffering. from a genetic immune deficiency to deliver healthy genes using disease. The goal was to get the liposomes—a type of oily droplet— William French therapeutic gene into the animals’ as a vector. Results from the first Anderson bone marrow, which would then clinical trial are due in 2014. make healthy red blood cells and cure the deficiency. The test was Considerable challenges still not very effective, although the remain to be overcome to extend procedure worked better when gene therapy. Cystic fibrosis is white blood cells were targeted. caused by a defect in just one gene. However, many conditions with In 1990, however, Anderson a genetic component—such as performed the first clinical trial, Alzheimer’s, heart disease, and treating two girls who both diabetes—are caused by the suffered from the same immune interplay of many different genes. Such conditions are far harder to treat, and the search for successful, safe gene therapies is ongoing. ■

324 DESIGNING NEW LIFE FORMS ON A COMPUTER SCREEN CRAIG VENTER (1946–) IN CONTEXT Living cells are The DNA’s instructions assembled and maintained are held in a BRANCH using instructions encoded Biology precise sequence. in DNA. BEFORE 1866 Gregor Mendel shows DNA can be created This sequence can that the inherited traits in pea artificially by bonding be deciphered. plants follow certain patterns. its chemical building blocks 1902 American biologist and in a particular order. physician Walter Sutton suggests that chromosomes One day we will be able to design new are the carriers of heredity. life forms on a computer screen. 1910–11 Thomas Hunt I n May 2010, an American 1771, Luigi Galvani used electricity Morgan proves Sutton’s theory team of scientists led by to make a dissected frog’s leg in fruit fly experiments. biologist Craig Venter created twitch, inspiring novelist Mary the first wholly artificial life form. Shelley to write Frankenstein. But 1953 Francis Crick and James The organism—a single-celled scientists gradually realized that Watson reveal how DNA bacterium—was assembled from life depends less on a physical carries genetic instructions. its raw chemical building blocks. “spark” and more on the chemical This was a testament to the processes taking place inside cells. 1995 A bacterium’s genome advance in our understanding of (complete set of genes) is the the nature of life itself. The dream By the mid-1950s, the real secret first to be sequenced. of creating life is nothing new. In of life had been found in a molecule called deoxyribonucleic acid, or 2000 The human genome is first sequenced. 2007 Craig Venter synthesizes an artificial chromosome. AFTER 2010 Venter announces the first synthesis of a life form.

FUNDAMENTAL BUILDING BLOCKS 325 See also: Gregor Mendel 166–71 ■ Thomas Hunt Morgan 224–25 ■ Barbara McClintock 271 ■ James Watson and Francis Crick 276–83 ■ Michael Syvanen 318–19 ■ William French Anderson 322–23 We are creating a new A random sequence would send a Computer-generated life value system for life. nonsense chemical “message” that The genome of even the simplest could not maintain a living thing. living thing—such as Mycoplasma— Craig Venter In order to create life, scientists had consists of sequences of hundreds to copy a sequence from a naturally of thousands of nucleotides. These DNA, which exists in the nucleus of existing organism. By 1990, new nucleotides must be artificially every cell. The long string of DNA’s technology was available to work bonded together in a specific order, chemical building blocks was this out through a host of complex but doing this for a whole genome identified as the genetic code that methods, and the international is a formidable task. The process is controls the workings of the cell. Human Genome Project was automated with the help of Creating life would mean creating launched to sequence the entire computer technology, on machines DNA—and getting the sequence of human genetic makeup, or genome. that can now decode the genetic building blocks, called nucleotides, blueprint of life, identify genetic exactly right. Nucleotides each The first organism—a factors in disease, and even serve have one of just four kinds of bases, bacterium—was sequenced in 1995. to create new life forms. ■ but combine in countless ways. Three years later, frustrated by the slow pace of the Human Genome Mycoplasma are bacteria that lack a Making DNA Project, Venter left to set up the cell wall. They are the smallest known The sequence of nucleotides differs private company Celera Genomics life forms, and were chosen by Venter in each organism, and is the result to sequence the human genome to be the first organisms to have their of millions of years of evolution. more quickly and to release the data chromosomes artificially sequenced. into the public domain. In 2007, his team announced that it had made an artificial chromosome—a complete string of DNA—based on that of a bacterium of the genus Mycoplasma. By 2010, his team had inserted an artificial chromosome into another bacterium whose genetic material had been removed, effectively creating a new life form. Craig Venter Born in Salt Lake City, Utah, whole genomes, focusing first Craig Venter performed poorly at on the bacterium Haemophilus school. Drafted into the Vietnam influenzae. Turning to the War, he worked in a field hospital human genome, he set up the and became drawn to biomedical profit-making company Celera science. After studying at the and helped build advanced University of California, San Diego, sequencing machines. In 2006, he joined the US National Institute he founded the not-for-profit of Health in 1984. In the 1990s, he J. Craig Venter Institute to helped develop technology that conduct research into the could locate genes in the human creation of artificial life forms. genetic makeup, becoming a pioneer in the growing field of Key works genome research. He left the NIH to set up the not-for-profit Institute 2001 The Sequence of the of Genomic Research in 1992. He Human Genome invented a way of sequencing 2007 A Life Decoded

326 A NEW LAW OF NATURE IAN WILMUT (1944–) IN CONTEXT C loning is the production of multicell organism was achieved a new, genetically identical in 1958 by British biologist BRANCH organism from a single F. C. Stewart, who grew a carrot Biology parent. It occurs in nature, such as plant from a single mature cell. when a strawberry plant sends out Cloning animals proved trickier. BEFORE runners and the offspring inherit all 1953 James Watson and their genes asexually. However, Cloning animals Francis Crick demonstrate artificial cloning is tricky, as not In animals, fertilized eggs and the that DNA has a double helix all cells have the potential to grow cells of a young embryo are among structure that carries the into complete individuals, and the few totipotent cells—cells that genetic code and can replicate. mature cells may be reluctant to do can grow to form a whole body. By so. The first successful cloning of a the 1980s, scientists could produce 1958 F. C. Stewart clones clones by separating young embryo carrots from mature The pressures for human cells, but it was difficult. British (differentiated) tissues. cloning are powerful; biologist Ian Wilmut and his team instead inserted the nuclei of body 1984 Danish biologist Steen but we need not assume cells into fertilized eggs that had Willadsen develops a way of that it will ever become a had their genetic material removed— fusing embryo cells with egg common or significant feature thereby making them totipotent. cells that have had their genetic material removed. of human life. Using udder cells of sheep as Ian Wilmut the source of nuclei, the team AFTER inserted the resultant embryos into 2001 The first endangered sheep to develop normally. In total, animal, a gaur (Indian bison) 27,729 of these cells grew into named Noah, is born in the US embryos, and one, named Dolly, by reproductive cloning. It dies born in 1996, survived into of dysentery two days later. adulthood. Research into cloning for agriculture, conservation, 2008 Therapeutic cloning of and medicine continues, as does tissue is shown to be effective public debate over its ethics. ■ at curing Parkinson’s disease in mice. See also: Gregor Mendel 166–71 ■ Thomas Hunt Morgan 224–25 ■ James Watson and Francis Crick 276–83

FUNDAMENTAL BUILDING BLOCKS 327 WORLDS BEYOND THE SOLAR SYSTEM GEOFFREY MARCY (1954–) IN CONTEXT A stronomers have long Planet hunter pondered the possibility of Astronomer Geoffrey Marcy at the BRANCH planets orbiting stars other University of California, Berkeley, Astronomy than our Sun, but technology has, along with his team, currently until recently, limited our ability holds the record for the most BEFORE to detect them. First to be found planets found by a human observer, 1960s Astronomers hope to were planets that orbited pulsars— including 70 out of the first 100. detect new planets through rapidly spinning neutron stars measurement of “wobbles” in whose radio signals vary slightly Such distant planets are too the paths of stars, but such as their planets pull them this way faint to be seen directly, but can movements remain beyond the and that. Then, in 1995, Swiss be revealed indirectly. The effect range of even the strongest astronomers Michel Mayor and of a planet’s gravity on its host star telescopes today. Didier Queloz discovered 51 Pegasi produces variations in the star’s b—a Jupiter-sized planet orbiting radial velocity—the speed at which 1992 Polish astronomer a Sunlike star about 51 light years it moves toward or away from Aleksander Wolszczan finds from Earth. Since then, more than Earth—which can be measured the first confirmed extrasolar 1,000 other extrasolar planets, or from changes in its light frequency. planets in orbit around a pulsar “exoplanets,” have been confirmed. Whether any exoplanets support (a burned-out stellar core). life remains to be seen. ■ AFTER The radial velocity method relies on Host star 2009–2013 NASA’s Kepler detecting slight Doppler shifts (p.127) satellite discovers more than in a star’s light frequency as it is pulled Blueshift as star moves 3,000 candidate exoplanets by back and forth in relation to Earth by toward Earth looking for minute drops in the the gravity of an orbiting planet. brightness of stars as planets pass in front of them. Based Redshift as star recedes from Earth Exoplanet on Kepler data, astronomers predict there could be as many See also: Nicolaus Copernicus 34–39 ■ William Herschel 86–87 ■ as 11 billion Earthlike worlds Christian Doppler 127 ■ Edwin Hubble 236–41 orbiting Sunlike stars in the Milky Way galaxy.

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RY

330 DIRECTORY F rom its roots with individuals or small groups working mostly in isolation, often in pursuit of quasi-religious goals, science has been transformed into a practical activity that is central to the working of modern society. Today, many projects are highly collaborative in nature, and it can be hard—and indeed invidious—to pick out particular figures. More areas of research exist than ever before, and the boundaries between disciplines are becoming blurred. Mathematicians provide solutions to the problems of physics and physicists explain the nature of chemical reactions, while chemists delve into the mysteries of life and biologists turn their attention to artificial intelligence. Here, we list just some of the figures who have added to our understanding of the world. PYTHAGORAS XENOPHANES ARYABHATA c.570–495 BCE c.570–475 BCE 476–550 CE Little is known for certain about Xenophanes of Colophon was an Working in Kusumapura, a center the life of the Greek mathematician itinerant Greek philosopher and of learning in India’s Gupta empire, Pythagoras, who did not leave poet. His wide-ranging interests the Hindu mathematician and behind any written work. He was reflected the knowledge he astronomer Aryabhata wrote a born on the Greek island of Samos, gained from careful observations short treatise that was to prove but left some time before 518 BCE for made on his extensive travels. highly influential among later Croton in southern Italy, where he He identified the energy of the Islamic scholars. Written in verse founded a secretive philosophical Sun that heats the oceans to when he was just 23 years old, the and religious society called the create clouds as the driving Arabhatiya contains sections on Pythagoreans. The society’s force behind physical processes arithmetic, algebra, trigonometry, inner circle called themselves on Earth. Xenophanes thought and astronomy. It includes an mathematikoi, and held that reality, that clouds were the origin of approximation of pi (π, the ratio at its deepest level, is mathematical heavenly bodies: the stars were of a circle’s circumference to its in nature. Pythagoras believed that burning clouds, while the Moon diameter) as 3.1416, which is the relations between all things was made of compressed cloud. accurate to four decimal places, could be reduced to numbers, and Upon discovering the fossilized and of Earth’s circumference as his group began discovering these remains of sea creatures far 24,835 miles (39,968km)—very relations. Among his many inland, he reasoned that Earth close to the current accepted contributions to science and alternated between periods of figure of 24,902 miles (40,075km). mathematics, Pythagoras studied flood and drought. Xenophanes Aryabhata also suggested that the the harmonics of vibrating strings, produced one of the earliest apparent movement of the stars and probably provided the first accounts of natural phenomena was due to the rotation of Earth and proof of the theorem that now bears that did not invoke divine forces that the orbits of the planets were his name: that the square of the to explain them, but his works ellipses, but appears to have fallen hypotenuse on a right-angled were largely neglected in the short of proposing a heliocentric triangle is equal to the sum of the centuries after his death. model of the solar system. squares of the other two sides. See also: Empedocles 21 ■ See also: Nicolaus Copernicus See also: Archimedes 24–25 Zhang Heng 26–27 34–39 ■ Johannes Kepler 40–41

DIRECTORY 331 BRAHMAGUPTA alchemy in Europe, but was medical descriptions of the probably written by the Franciscan condition known as “phantom 598–670 monk Paul of Taranto. At the time, limb,” in which the patient feels it was common practice for an sensation in a limb after it has The Indian mathematician author to adopt the name of been amputated. He also made and astronomer Brahmagupta an illustrious predecessor. artificial eyes from gold, silver, introduced the concept of zero into See also: John Dalton 112–13 porcelain, and glass. Paré the number system, defining it examined the internal organs of as the result of subtracting a IBN-SINA people who had died violent deaths number from itself. He also detailed and wrote the first legal medical the arithmetic rules for dealing 980–1037 reports, marking the beginning of with negative numbers. He wrote modern forensic pathology. Paré’s his major work in 628, while living Also known as Avicenna, the work raised the previously low and working in Bhillamala, the Persian physician Abu ‘Ali social status of surgeons, and he capital city of the Gurjara-Pratihara al-Husayn Ibn-Sina was a child acted as personal surgeon to four dynasty. Called Brahma-sphuta- prodigy who had memorized French kings. Les Oeuvres (The siddhanta (The Correct Treatise of the entire Koran by the age Works), a book detailing his the Brahma), the work contained no of 10. He wrote widely on topics techniques, was published in 1575. mathematical symbols but included including mathematics, logic, See also: Robert Hooke 54 a full description of the quadratic astronomy, physics, alchemy, and formula, a means of solving music, producing two major works: WILLIAM HARVEY quadratic equations. The work the Kitab al-shifa (The Book of was translated into Arabic in Healing), a huge encyclopedia of 1578–1657 Baghdad the following century science; and Al-Qanun fi al-Tibb and was a major influence on (The Canon of Medicine), which English physician William Harvey later Arab scientists. was to remain in use as a produced the first accurate See also: Alhazen 28–29 university textbook into the 17th description of the circulation of century. Ibn-Sina outlined not only blood, showing that it flows rapidly JABIR IBN-HAYYAN medical cures but also ways to stay through the body in one system healthy, stressing the importance pumped by the heart. Previously, c.722–c.815 of exercise, massage, diet, and there were thought to be two blood sleep. He lived through a period systems: the veins carried purple The Persian alchemist Jabir of political upheaval and often blood full of nutrients from the liver, Ibn-Hayan, also known by found his studies interrupted by while the arteries carried scarlet the latinized name Geber, was a the need to stay on the move. “life-giving” blood from the lungs. practical, experimental scientist, See also: Louis Pasteur 156–59 Harvey demonstrated blood flow who outlined detailed methods in numerous experiments, and for, among other things, making AMBROISE PARÉ studied the heartbeats of various alloys, testing metals, and animals. However, he was opposed fractional distillation. Almost c1510–1590 to the mechanical philosophy of 3,000 different books have been Descartes, and believed that blood attributed to Jabir, but many were Ambroise Paré spent 30 years had its own life force. Initially probably written in the century working as a military surgeon in resisted, by the time of his death, after his death. Few of Jabir’s the French army, during which Harvey’s theory of circulation was works were known to medieval time he developed many new widely accepted. Smaller capillaries Europe, but a work attributed to techniques, including the use linking the arteries and veins were him, called Summa Perfectionis of ligatures to tie arteries after discovered under new microscopes Magisterii (The Sum of Perfection), amputation of a limb. He studied in the late 17th century. appeared in the 13th century. It anatomy, developed artificial limbs, See also: Robert Hooke 54 ■ became the best-known book on and produced one of the first Antonie van Leeuwenhoek 56–57

332 DIRECTORY MARIN MERSENNE problems into their simplest parts; science as he discovered the ideas solve the problems by moving from of Descartes, Bacon, and Galileo, 1588–1648 the simple to the complex; and, which marked the start of a lastly, check your results. He also lifelong quest to collate all human The French monk Marin Mersenne developed the Cartesian system knowledge. He later studied is best remembered today for his of coordinates—with x, y, and z mathematics in Paris under work on prime numbers, showing axes—to represent points in space Christiaan Huygens, and it was that if the number 2n–1 is prime, using numbers. This allowed here that he began to develop then n must also be prime. He shapes to be expressed as numbers calculus—a mathematical means also conducted extensive studies and numbers to be expressed as of calculating rates of change in many scientific fields, including shapes, founding the mathematical that was to prove crucial to harmonics, in which he figured out field of analytical geometry. the development of science. He the laws that govern the frequency See also: Galileo Galilei 42–43 ■ developed calculus at the same of vibrations of a stretched string. Francis Bacon 45 time as Isaac Newton, with whom Mersenne lived in Paris, where he he corresponded and then fell out. collaborated with René Descartes, HENNIG BRAND Leibniz actively promoted the study and corresponded extensively with of science, corresponding with Galileo, whose works he translated c.1630–c.1710 more than 600 scientists across into French. He strongly advocated Europe and setting up academies experiment as the key to scientific Little is known about the early life in Berlin, Dresden, Vienna, and understanding, stressing the need of German chemist Hennig Brand. St. Petersburg. for accurate data and criticizing We do know that he fought in the See also: Christiaan Huygens many of his contemporaries for Thirty Years’ War and dedicated 50–51 ■ Isaac Newton 62–69 their lack of rigor. In 1635, he himself to alchemy on leaving the founded the Académie Parisienne, army, searching for the elusive DENIS PAPIN a private scientific association with philosopher’s stone that would more than 100 members across turn base metal into gold. In 1669, 1647–1712 Europe, which would later become Brand produced a waxy, white the French Academy of Sciences. material by heating the residue of As a young man, French-born See also: Galileo Galilei 42–43 boiled-down urine. He called this English physicist and inventor material “phosphorus” (“light- Denis Papin assisted both RENÉ DESCARTES carrier”) because it glowed in the Christiaan Huygens and Robert dark. Phosphorus is highly reactive Boyle in their experiments on air 1596–1650 and never found as a free element and pressure, and in 1679, he on Earth, and this marked the first invented the pressure cooker. The French philosopher René time that such an element had been Observing how the steam in Descartes was a key figure in isolated. Brand kept his method the cooker tended to raise the lid, the Scientific Revolution of the secret, but phosphorus was Papin then came up with the idea 17th century, traveling widely discovered independently by of using steam to drive a piston across Europe and working with Robert Boyle in 1680. in a cylinder, and produced the many of the prominent figures of See also: Robert Boyle 46–49 first design for a steam engine. his day. He helped European Papin never built a steam scientists to finally overcome GOTTFRIED LEIBNIZ engine himself, but in 1709, he Aristotle’s nonempirical approach constructed a paddle wheel that by applying a thorough scepticism 1646–1716 demonstrated the practicability to assumed knowledge. Descartes of using paddles instead of oars produced a four-pronged method The German Gottfrield Leibniz in steam-powered ships. of scientific inquiry, based on studied law at the University of See also: Robert Boyle 46–49 ■ mathematics: accept nothing as Leipzig. During his studies, he Christiaan Huygens 50–51 ■ true unless it is self-evident; divide became increasingly interested in Joseph Black 76–77

DIRECTORY 333 STEPHEN HALES must exchange some of its pressure letters, White laid out a record for kinetic energy in order not to of his systematic observations of 1677–1761 violate the principle of the nature and developed his ideas conservation of energy. In addition about the interrelationships English clergyman Stephen Hales to mathematics and physics, of living things. He was, in conducted a series of pioneering Bernoulli studied astronomy, effect, the first ecologist. White experiments on plant physiology. biology, and oceanography. recognized that all living things He measured the water vapor See also: Joseph Black 76–77 ■ have a role to play in what we emitted by the leaves of plants Henry Cavendish 78–79 ■ Joseph would now call the ecosystem, in a process called transpiration, Priestley 82–83 ■ James Joule 138 noting of earthworms that they and this led him to the discovery ■ Ludwig Boltzmann 139 “seem to be the great promoters that transpiration drives a of vegetation, which would continuous upward flow of GEORGES-LOUIS LECLERC, proceed but lamely without them.” fluid from the roots that carries COMTE DE BUFFON White’s methods, including taking dissolved nutrients around the recordings in the same places over whole plant. Sap moves from an 1707–1788 many years, were highly influential area of high pressure in the roots on subsequent biologists. to areas of lower pressure where From 1749 to the end of his life, See also: Alexander von Humboldt water vapor is transpiring. French aristocrat and naturalist the 130–35 ■ James Lovelock 315 Hales published his results Comte de Buffon worked tirelessly in 1727 in the book Vegetable on his monumental work Histoire NICÉPHORE NIEPCE Staticks. In addition, he conducted Naturelle (Natural History). His extensive experiments with goal was to collate all knowledge 1765–1833 animals, particularly dogs, in the fields of natural history and measuring blood pressure for the geology. The encyclopedia spanned The oldest surviving photograph first time. Hales also invented 44 volumes when it was finally was taken in 1825 by French the pneumatic trough, an apparatus completed by his assistants 16 inventor Nicéphore Niepce of the used to collect the gases emitted years after his death. Buffon buildings around his country estate during chemical reactions. constructed a geological history of in Saint-Loup-de-Varennes. Niepce See also: Joseph Priestley 82–83 ■ Earth, suggesting that it was much had been experimenting for several Jan Ingenhousz 85 older than previously assumed. He years to find a technique to fix charted the extinction of species the image projected onto the back DANIEL BERNOULLI and suggested a common ancestor of a camera obscura. In 1816, he of humans and apes, predating produced a negative image using 1700–1782 Charles Darwin by a century. paper coated with silver chloride, See also: Carl Linnaeus 74–75 ■ but the image disappeared when Daniel Bernoulli was perhaps the James Hutton 96–101 ■ Charles exposed to daylight. Then around most gifted in a remarkable family Darwin 142–49 1822, he came up with a process he of Swiss mathematicians—his called heliography, which used a uncle Jakob and father Johann both GILBERT WHITE plate of glass or metal coated with did important work in developing bitumen. The bitumen hardened calculus. In 1738, he published 1720–1793 when it was exposed to light, and Hydrodynamica, in which he when the plate was washed with examined the properties of fluids. British parson Gilbert White was lavender oil, only the hardened He formulated Bernoulli’s principle, an unmarried curate who lived a areas remained. It took eight hours that a fluid’s pressure decreases as quiet life in the small Hampshire of exposure to fix the images. its velocity increases. This principle village of Selborne. His 1789 book, Near the end of his life, Niepce is key to understanding how the The Natural History and Antiquities collaborated with Louis Daguerre wings of an airplane produce lift. of Selborne, was a compilation of on ways to improve the process. He realized that a moving fluid letters written to his friends. In his See also: Alhazen 28–29

334 DIRECTORY ANDRÉ-MARIE AMPÈRE description of his process, called to Babbage’s specification, using the daguerreotype, in 1839, and only technology that would have 1775–1836 it made him a fortune. been available at the time, and it See also: Alhazen 28–29 worked, though it tended to jam Upon hearing of Hans Christian after a minute or two. Babbage Ørsted’s accidental discovery AUGUSTIN FRESNEL also dreamed of a steam-powered of the link between electricity “Analytical Engine,” which would and magnetism in 1820, French 1788–1827 take instructions on punched physicist André-Marie Ampère cards, hold data in a “store,” carry started formulating a mathematical French engineer and physicist out calculations in the “mill,” and and physical theory that explained Augustin Fresnel is best known print out the results. This might their relationship. In the process, as the inventor of the Fresnel have been a real computer in the he formulated Ampère’s law, which lens, which allows the light from modern sense. His protégée Ada states the mathematical relation a lighthouse to be seen over Lovelace (the daughter of poet Lord of a magnetic field to the electric greater distances. He studied Byron) wrote programs for it, and current that produces it. Ampère the behavior of light, building has been called the world’s first published his results in 1827, on the double-slit experiments of computer programmer. However, and his book, Memoir on the Thomas Young, with whom he the Analytical Engine project Mathematical Theory of corresponded. Fresnel conducted never got off the ground. Electrodynamic Phenomena, a great deal of important theoretical See also: Alan Turing 252–53 uniquely deduced from experience, work on optics, producing a set gave a name to this new scientific of equations describing how light SADI CARNOT field—electrodynamics. The is refracted or reflected as it standard unit of electric current, passes from one medium to 1796–1832 the ampere (or amp), is named another. The importance of after him. much of his work was only Nicolas-Léonard-Sadi Carnot was See also: Hans Christian Ørsted recognized after his death. an officer in the French army who 120 ■ Michael Faraday 121 See also: Alhazen 28–29 ■ semiretired on half-pay to Paris in Christiaan Huygens 50–51 ■ 1819 to devote himself to science. LOUIS DAGUERRE Thomas Young 110–11 Hoping to see France catch up with Britain in the Industrial Revolution, 1787–1851 CHARLES BABBAGE Carnot began designing and building steam engines. His The first practical photographic 1791–1871 research led to his only publication, process was invented by the in 1824, Reflections on the Motive French painter and physicist Louis British mathematician Charles Power of Fire, in which he noted Daguerre. From 1826, Daguerre Babbage conceived the first digital that the efficiency of a steam collaborated with Nicéphore Niepce computer. Appalled by the number engine depends principally on the on his heliographic process, but of errors in printed mathematical temperature difference between this needed at least eight hours of tables, Babbage designed a the hottest and coldest parts of the exposure. Following Niepce’s death machine to calculate the tables engine. This pioneering work in 1833, Daguerre developed a automatically, and in 1823 hired on thermodynamics was later process in which an image on an engineer Joseph Clement to build developed by Rudolf Clausius in iodized silver plate was developed it. His “Difference Engine” was to Germany and William Thomson, by exposure to mercury fumes and be an elegant contraption of brass Lord Kelvin in Britain, but was fixed using saline. This reduced cogwheels, but Babbage got only largely ignored in Carnot’s lifetime. the exposure time required to as far as a prototype before running He died in relative obscurity during 20 minutes, making it practical to out of money and energy. In 1991, a cholera epidemic, at just 36. take photographs of people for the scientists at London’s Science See also: Joseph Fourier 122 ■ first time. Daguerre wrote a full Museum built a Difference Engine James Joule 138

DIRECTORY 335 JEAN-DANIEL COLLADON CLAUDE BERNARD invented the mirror galvanometer to receive faint telegraph signals, 1802–1893 1813–1878 and presided over the laying of the transatlantic cable in 1866. He Swiss physicist Jean-Daniel French physiologist Claude Bernard also invented an improved Colladon demonstrated that light was a pioneer in experimental mariner’s compass and a tide- could be trapped by total internal medicine. He was the first scientist predicting machine. Lord Kelvin reflection inside a tube, allowing it to study the internal regulation often courted controversy, rejecting to travel along a curved path—a of the body, and his work was to Darwin’s theory of evolution and core principle behind modern-day lead to the modern concept of making many bold statements— optical fibers. In experiments homeostasis—the mechanism including the prediction that “no conducted on Lake Geneva, by which the body maintains aeroplane will ever be practically Colladon demonstrated that sound a stable internal environment successful,” made one year before travels four times more quickly while the external environment the Wright brothers’ first flight in through water than through air. He changes. Bernard studied the 1903. However, a quote widely transmitted sound through water roles of the pancreas and liver attributed to Lord Kelvin stating over a distance of 30 miles (50km), in digestion, and described how that “there is nothing new to be and proposed using this method chemicals are broken down into discovered in physics now” is as a means of communicating simpler substances only to be almost certainly apocryphal. across the English Channel. He built up again into the complex See also: James Joule 138 ■ also conducted important work in molecules needed to make Ludwig Boltzmann 139 ■ the field of hydraulics, studying the body tissues. His major work, Ernest Rutherford 206–213 compressibility of water. An Introduction to the Study of See also: Léon Foucault 136–37 Experimental Medicine, was JOHANNES VAN published in 1865. DER WAALS JUSTUS VON LIEBIG See also: Louis Pasteur 156–59 1837–1923 1803–1873 WILLIAM THOMSON Dutch physicist Johannes van The son of a chemical manufacturer 1824–1907 der Waals made a significant in Darmstadt, Germany, Justus contribution to the field of von Liebig conducted his first Born in Belfast, physicist William thermodynamics with his 1873 chemistry experiments as a child Thomson became professor of doctoral thesis, in which he showed in his father’s laboratory. He natural philosophy at Glasgow that there is a continuity between grew up to become a charismatic University at 22 years old. In 1892, a liquid and gaseous state at a professor of chemistry whose he was ennobled, and became molecular level. Van der Waals laboratory-based teaching methods Baron Kelvin, after the river that showed not only that these two were hugely influential. Von Liebig runs through Glasgow University. states of matter merge into one discovered the importance of Kelvin viewed physical change as another, but also that they should nitrates to plant growth and fundamentally a change in energy, be considered as essentially developed the first industrial and his work produced a synthesis of the same nature. He postulated fertilizers. He was also interested of many areas of physics. He the existence of forces between in the chemistry of food and developed the second law of molecules, which are now called developed a manufacturing process thermodynamics and established the van der Waals forces, and to produce beef extracts. The the correct value for “absolute which explain properties of company he founded, the Liebig zero,” the temperature at which all chemicals such as their solubility. Extract of Meat Company, would molecular movement ceases, at See also: James Joule 138 ■ later produce the trademarked –459.6°F (–273.15°C). The Kelvin Ludwig Boltzmann 139 ■ Oxo stock cubes. scale, which starts at 0 at absolute August Kekulé 160–65 ■ See also: Friedrich Wöhler 124–25 zero, is named after him. He Linus Pauling 254–59

336 DIRECTORY ÉDOUARD BRANLY the dogs would salivate just when of artificial fertilizers, greatly hearing the bell. In this work, increasing food production. On the 1844–1940 Pavlov laid the groundwork for negative side, Haber developed the scientific study of behavior, chlorine and other deadly gases A physics professor at the although physiologists today for use in trench warfare, and Paris Catholic Institute, Édouard consider his explanations to personally oversaw their use on Branly was a pioneer in wireless be oversimplified. battlefields during World War I. telegraphy. In 1890, he invented a See also: Konrad Lorenz 249 His wife Clara, also a chemist, radio receiver known as the Branly killed herself in 1915 in opposition coherer. The receiver was a tube HENRI MOISSAN to her husband’s involvement in with two electrodes inside it the use of chlorine gas at Ypres. spaced a little apart, and metal 1852–1907 See also: Friedrich Wöhler 124–25 filings in the space between the ■ August Kekulé 160–65 electrodes. When a radio signal French chemist Henri Moissan was applied to the receiver, the received the 1906 Nobel Prize in C. T. R. WILSON resistance of the filings was Chemistry for his work isolating reduced, allowing an electric the element fluorine, which he 1869–1959 current to flow between the produced by electrolysing a solution electrodes. Branly’s invention of potassium hydrogen difluoride. Charles Thomson Rees Wilson was used in later experiments on When Moissan cooled the solution was a Scottish meteorologist with radio communication by Italian to –58°F (–50°C), pure hydrogen a particular interest in the study Guglielmo Marconi, and widely appeared at the negative electrode, of clouds. To help his studies, used in telegraphy up to 1910, and pure fluorine at the positive he developed a method of when more sensitive detectors one. Moissan also developed an expanding moist air inside a were developed. electric-arc furnace that could closed chamber to produce the See also: Alessandro Volta reach a temperature of 6,300°F state of supersaturation needed 90–95 ■ Michael Faraday 121 (3,500°C), which he used in his for cloud formation. Wilson found attempts to synthesize artificial that clouds formed in the chamber IVAN PAVLOV diamonds. He did not succeed, but much more easily in the presence his theory that diamonds could be of dust particles. In the absence of 1849–1936 made by putting carbon under high dust, clouds only formed when pressure at high temperatures was the saturation of the air passed a The son of a priest, Russian subsequently proved correct. critical high point. Wilson believed Ivan Pavlov abandoned plans to See also: Humphry Davy 114 ■ that clouds were forming on ions follow in his father’s footsteps Leo Baekeland 140–41 (charged molecules) in the air. in order to study chemistry and To test this theory, he passed physiology at the University of FRITZ HABER radiation through the chamber St. Petersburg. In the 1890s, to see whether the resultant ion Pavlov was studying salivation in 1868–1934 formation would cause clouds to dogs when he noticed that his dogs form. He found that the radiation would salivate whenever he entered The scientific legacy of German left a trail of condensed water the room, even if he had no food chemist Fritz Haber is mixed. vapor in its wake. Wilson’s with him. Pavlov realized that this On the positive side, Haber cloud chamber proved crucial must be a learned behavior, and and his colleague Carl Bosch for studies in nuclear physics, started 30 years of experiments developed a process for synthesizing and won him the Nobel Prize in into what he called “conditioned ammonia (NH3) from hydrogen and Physics in 1927. In 1932, the responses.” In one experiment, he atmospheric nitrogen. Ammonia is positron was first detected would ring a bell every time he fed an essential ingredient of fertilizers, using a cloud chamber. the dogs. He found that after a and the Haber–Bosch process See also: Paul Dirac 246–47 ■ period of learning (conditioning), allowed the industrial production Charles Keeling 294–95

DIRECTORY 337 EUGÈNE BLOCH citizen in 1939. He was awarded a Palade developed new techniques Nobel Prize in Physics for his work for tissue preparation that allowed 1878–1944 on quantum mechanics in 1954. him to examine the structure of See also: Erwin Schrödinger cells under an electron microscope, French physicist Eugène Bloch 226–33 ■ Werner Heisenberg and this work greatly advanced conducted studies in spectroscopy, 234–35 ■ Paul Dirac 246–47 ■ the understanding of cellular and produced evidence in J. Robert Oppenheimer 260–65 organization. His most important support of Albert Einstein’s achievement was the discovery in interpretation of the photoelectric NIELS BOHR the 1950s of ribosomes—bodies effect using the idea of quantized inside cells that were previously light. During World War I, 1885–1962 thought to be fragments of Bloch worked on military mitochondria, but are in fact the communications, developing the One of the leading early theorists primary sites of protein synthesis, first electronic amplifiers for radio of quantum physics, Dane Niels linking together amino acids in a receivers. In 1940, he fell victim to Bohr’s first major contribution to specific sequence. the anti-Jewish laws of the Vichy the quantum revolution was to See also: James Watson and government and was dismissed refine Ernest Rutherford’s model of Francis Crick 276–83 ■ from his post as a professor of the atom. In 1913, Bohr added the Lynn Margulis 300–01 physics at the University of Paris. idea that electrons occupy specific He fled to unoccupied southern quantized orbits around the DAVID BOHM France, but was captured by the nucleus. In 1927, Bohr collaborated Gestapo in 1944 and deported to with Werner Heisenberg to 1917–1992 Auschwitz, where he was killed. formulate an explanation of See also: Albert Einstein 214–21 quantum phenomena that came American theoretical physicist to be known as the Copenhagen David Bohm advanced an MAX BORN interpretation. A concept central unconventional interpretation of to this interpretation was Bohr’s quantum mechanics. He postulated 1882–1970 complementarity principle, which the existence of an “implicate states that a physical phenomenon, order” to the universe that is a more In the 1920s, German physicist such as the behavior of a photon or fundamental order of reality than Max Born, while professor an electron, may express itself the phenomena we experience as of experimental physics at differently depending on the time, space, and consciousness. the University of Göttingen, experimental set-up used to He wrote: “an entirely different sort collaborated with Werner observe it. of basic connection of elements is Heisenberg and Pascual Jordan See also: Ernest Rutherford possible, from which our ordinary to formulate matrix mechanics, 206–13 ■ Erwin Schrödinger notions of space and time, along a mathematical means of dealing 226–33 ■ Werner Heisenberg with those of separately existent with quantum mechanics. When 234–35 ■ Paul Dirac 246–47 material particles, are abstracted Erwin Schrödinger formulated his as forms derived from the deeper wave function equation to describe GEORGE EMIL PALADE order.” Bohm worked with Albert the same thing, Born was the first Einstein at Princeton University to suggest the real-world meaning 1912–2008 until the early 1950s, when his of Schrödinger’s mathematics—it Marxist political views led him to described the probability of finding Romanian cell biologist George leave the US—first for Brazil and a particle at a specific point on the Emil Palade graduated in medicine later London, where he was a space-time continuum. In 1933, from the University of Bucharest professor of physics at Birkbeck Born and his family left Germany in 1940. He emigrated to the US College from 1961. when the Nazis dismissed Jews at the end of World War II, and did See also: Erwin Schrödinger from academic posts. He settled his most important work at the 226–33 ■ Hugh Everett III 284–85 ■ in Britain, becoming a British Rockefeller Institute in New York. Gabriele Veneziano 308–13

338 DIRECTORY FREDERICK SANGER theory of intelligence, investigating show how matter in a black hole the way in which intelligence can collapses into a singularity. 1918–2013 emerge from a system made solely Penrose subsequently worked of nonintelligent parts. Minsky out the mathematics to describe British biochemist Frederick Sanger defines AI as “the science of the effects of gravity on the is one of four scientists to have making machines do things that space-time surrounding a black won two Nobel prizes, both would require intelligence if done hole. Penrose has turned his in Chemistry. He won his first by men.” He was an advisor on the attention to a wide range of prize in 1958 for determining the film 2001: A Space Odyssey, and topics, proposing a theory sequence of amino acids that make has speculated as to the possibility of consciousness based on up the protein insulin. Sanger’s of extraterrestrial intelligence. quantum mechanical effects work on insulin provided a key to See also: Alan Turing 252–53 ■ operating at a subatomic level in understanding the way that DNA Donald Michie 286–91 the brain, and more recently a codes for making proteins, by theory of a cyclic cosmology, in showing that each protein has its MARTIN KARPLUS which the heat death (end state) of own unique sequence of amino one universe becomes the Big Bang acids. Sanger’s second prize was 1930– of another, in an endless cycle. awarded in 1980 for his later work See also: Georges Lemaître sequencing DNA. Sanger’s team Increasingly, modern science is 242–45 ■ Subrahmanyan sequenced human mitochondrial conducted using computers to Chandrasekhar 248 ■ DNA—a set of 37 genes found on model results. In 1974, American- Stephen Hawking 314 mitochondria that is inherited Austrian theoretical chemist only from the mother. The Sanger Martin Karplus and his colleague, FRANÇOIS ENGLERT Institute, now one of the world’s American-Israeli Arieh Warshel, leading centers of genomic produced a computer model of the 1932– research, was established in complex molecule retinal, which his honor near his home in changes shape when exposed to In 2013, Belgian physicist Cambridgeshire, Britain. light and is crucial to the working François Englert shared the See also: James Watson of the eye. Karplus and Warshel Nobel Prize in Physics with Peter and Francis Crick 276–83 ■ used both classical physics and Higgs for independently proposing Craig Venter 324–25 quantum mechanics to model the what is now known as the Higgs behavior of electrons in the retinal field, which gives fundamental MARVIN MINSKY molecule. Their model greatly particles their mass. Working improved the sophistication and with fellow Belgian Robert Brout, 1927– accuracy of computer modeling for Englert first suggested in 1964 complex chemical systems. Karplus that “empty” space might contain American mathematician and and Warshel shared the 2013 Nobel a field that confers mass to matter. cognitive scientist Marvin Minsky Prize in Chemistry with British The Nobel Prize was awarded as was an early pioneer in artificial chemist Michael Levitt for their a result of the detection in 2012 intelligence, co-founding in achievement in this field. at CERN of the Higgs boson— 1959 the AI laboratory at the See also: Augus Kekulé 160–65 ■ the particle associated with the Massachusetts Institute of Linus Pauling 254–59 Higgs field—which confirmed Technology (MIT), where he spent Englert, Brout, and Higgs’ the rest of his career. His work ROGER PENROSE predictions. Brout had died focused on the generation of in 2011, and so missed out on neural networks—artificial “brains” 1931– the Nobel Prize, which is not that can develop and learn from awarded posthumously. experience. In the 1970s, Minsky In 1969, British mathematician See also: Sheldon Glashow and his colleague Seymour Papert Roger Penrose collaborated with 292–93 ■ Peter Higgs 298–99 ■ developed the “Society of Mind” physicist Stephen Hawking to Murray Gell-Mann 302–07

DIRECTORY 339 STEPHEN JAY GOULD contained in its genetic code. Its MICHAEL TURNER phenotype is that which results 1941–2002 from the expression of that code. 1949– While individual genes may simply American paleontologist Stephen code for the synthesis of different American cosmologist Michael Jay Gould’s specialized area of substances in an organism’s Turner’s research focuses on research concerned the evolution body, the phenotype should be understanding what happened of land snails in the West Indies, considered to be everything that directly following the Big Bang. but he wrote widely about many results from that synthesis. For Turner believes that the structure aspects of evolution and science. example, a termite mound may be of the universe today, including In 1972, Gould and colleague Niles considered to be part of a termite’s the existence of galaxies and the Eldredge proposed the theory of extended phenotype. Dawkins asymmetry between matter and “punctuated equilibrium,” which views the extended phenotype antimatter, can be explained by proposed that, rather than being as the means by which genes quantum-mechanical fluctuations a constant, gradual process maximize their chances of that took place during the rapid as Darwin had imagined, the survival to the next generation. burst of expansion called cosmic evolution of new species took place See also: Charles Darwin inflation, which occurred moments in rapid bursts over periods as short 142–49 ■ Lynn Margulis 300–01 ■ after the Big Bang. In 1998, Turner as a few thousand years, which Michael Syvanen 318–19 coined the term “dark energy” to were followed by long periods of describe the hypothetical energy stability. To back up their claim, JOCELYN BELL BURNELL that permeates the whole of space they cited evidence from the and explains the observation that fossil record, in which patterns 1943– the universe is expanding in all of evolution in various organisms directions at an accelerating rate. support their theory. In 1982, In 1967, while working as a See also: Edwin Hubble 236–41 ■ Gould coined the term “exaptation” research assistant at Cambridge Georges Lemaître 242–45 ■ to describe the way in which a University, British astronomer Fritz Zwicky 250–51 particular trait may be passed Jocelyn Bell was monitoring on for one reason, and then later quasars (distant galactic nuclei) TIM BERNERS-LEE come to be coopted for a very when she discovered a strange different function. His work series of regular radio pulses 1955– widened understanding of the coming from space. The team she mechanisms by which natural was working with jokingly called Few living scientists have had selection takes place. the pulses LGM (Little Green Men), as much impact on everyday life as See also: Charles Darwin referring to the remote chance British computer scientist Tim 142–49 ■ Lynn Margulis 300–01 ■ that they were an attempt at Berners-Lee, who invented the Michael Syvanen 318–19 extraterrestrial communication. World Wide Web. In 1989, Berners- They later determined that the Lee was working at CERN, the RICHARD DAWKINS sources of the pulses were rapidly European Organization for Nuclear spinning neutron stars, which Research, when he had the idea 1941– were dubbed pulsars. Two of Bell’s of establishing a network of senior colleagues were awarded documents that could be shared British zoologist Richard Dawkins the 1974 Nobel Prize in Physics across the world via the Internet. is best known for his popular for the discovery of pulsars, but Bell A year later, he wrote the first science books, including The missed out because she was only a web client and server, and in Selfish Gene (1976). His most student at the time. Many leading 1991, CERN built the first website. significant contribution to his field astronomers, including Fred Hoyle, Today, Berners-Lee campaigns for is his concept of the “extended objected publicly to her omission. open access to the Internet, free phenotype.” An organism’s genotype See also: Edwin Hubble 236–41 ■ from government control. is the sum of the instructions Fred Hoyle 270 See also: Alan Turing 252–53

340 GLOSSARY Absolute zero The lowest Atom The smallest part of an Cell The smallest unit of an possible temperature: 0K or element that has the chemical organism that can survive on its –459.67°F (–273.15°C). properties of that element. An atom own. Organisms such as bacteria was thought to be the smallest part and protists are single cells. Acceleration The rate of change of matter, but many subatomic of velocity. Acceleration is caused particles are now known. Chaotic system A system whose by a force that results in a change behavior over time changes in an object’s direction and/or speed. Atomic number The number radically in response to small of protons in an atom’s nucleus. changes to its initial condition. Acid A chemical that, when Each element has a different dissolved in water, liberates atomic number. Chromosome A structure made hydrogen ions and turns litmus red. of DNA and protein that contains ATP Adenosine triphosphate. a cell’s genetic information. Algorithm In mathematics and A chemical that stores and computer-programming, a logical transports energy across cells. Cladistics A system for classifying procedure for making a calculation. life that groups species according Base A chemical that reacts with to their closest common ancestors. Alkali A base that dissolves an acid to make water and a salt. in water and neutralizes acids. Classical mechanics Also known Beta decay A form of radioactive as Newtonian mechanics. A set Alpha particle A particle made decay in which an atomic nucleus of laws describing the motion of of two neutrons and two protons, gives off beta particles (electrons bodies under the action of forces. which is emitted during a form of or positrons). Classical mechanics gives accurate radioactive decay called alpha results for macroscopic objects decay. An alpha particle is identical Big Bang The theory that that are not traveling close to to the nucleus of a helium atom. the universe began from an the speed of light. explosion of a singularity. Amino acids Organic chemicals Color charge A property of quarks with molecules that contain amino Black body A theoretical object by which they are affected by the groups (NH2) and carboxyl groups that absorbs all radiation that falls strong nuclear force. (COOH). Proteins are made from on it. A black body radiates energy amino acids. Each different protein according to its temperature, so Continental drift The slow contains a specific sequence may not in fact appear black. movement of continents around of amino acids. the globe over millions of years. Black hole An object in space that Angular momentum A measure is so dense that light cannot escape Covalent bond A bond of the rotation of an object, which its gravitational field. between two atoms in which takes into account its mass, shape, they share electrons. and spin speed. Bosons Subatomic particles that carry forces between Dark energy A poorly understood Antiparticle A particle that is the other particles. force that acts in the opposite same as a normal particle except direction to gravity, causing the that it has an opposite electrical Brane In string theory, an universe to expand. About three charge. Every particle has an object that has between zero quarters of the mass-energy of equivalent antiparticle. and nine dimensions. the universe is dark energy.

GLOSSARY 341 Dark matter Invisible matter Electrolysis A chemical change Fermion A subatomic particle, that can only be detected by its in a substance caused by passing such as an electron or a quark, that gravitational effect on visible an electric current through it. is associated with mass. matter. Dark matter holds galaxies together. Element A substance that Field The distribution of a force cannot be broken down into other across space-time, in which each Diffraction The bending of waves substances by chemical reactions. point can be given a value for that around obstacles and spreading out force. A gravitational field is an of waves past small openings. Endosymbiosis A relationship example of a field in which the force between organisms in which one felt at a particular point is inversely DNA Deoxyribonucleic acid. A organism lives inside the body or proportional to the square of the large molecule in the shape of a cells of another organism to their distance from the source of gravity. double helix that carries genetic mutual benefit. information in a chromosome. Force A push or a pull, which moves Energy The capacity of an object or changes the shape of an object. Doppler effect The change in or system to do work. Energy can frequency of a wave experienced exist in many forms, such as Fractal A geometric pattern in by an observer in relative motion kinetic energy (movement) and which similar shapes can be seen to the wave’s source. potential energy (for example, the at different scales. energy stored in a spring). It can Ecology The scientific study of change from one form to another, Gamma decay A form of the relationships between living but never be created or destroyed. radioactive decay in which organisms and their environment. an atomic nucleus gives off Entanglement In quantum high-energy, short-wavelength Electric charge A property of physics, the linking between gamma radiation. subatomic particles that causes particles such that a change in one them to attract or repel one another. affects the other no matter how Gene The basic unit of heredity of far apart in space they may be. living organisms, which contains Electric current A flow of coded instructions for the formation electrons or ions. Entropy A measure of the of chemicals such as proteins. disorder of a system. Entropy Electromagnetic force One is the number of specific ways a General relativity A theoretical of the four fundamental forces of particular system may be arranged. description of space-time in which nature. It involves the transfer Einstein considers accelerating of photons between particles. Ethology The scientific study of frames of reference. General animal behavior. relativity provides a description Electromagnetic radiation A of gravity as the warping of form of energy that moves through Event horizon A boundary space-time by mass. Many space. It has both an electrical and surrounding a black hole within of its predictions have been a magnetic field, which oscillate at which the gravitational pull of the demonstrated empirically. right-angles to each other. Light is a black hole is so strong that light form of electromagnetic radiation. cannot escape. No information Geocentrism A model of the about the black hole can cross its universe with Earth at its center. Electroweak theory A theory event horizon. that explains the electromagnetic Gravity A force of attraction and weak nuclear force as one Evolution The process by which between objects with mass. “electroweak” force. species change over time. Massless photons are also affected by gravity, which Electron A subatomic particle Exoplanet A planet that orbits a general relativity describes with a negative electric charge. star that is not our Sun. as a warping of space-time.

342 GLOSSARY Greenhouse gases Gases Mitochondria Structures Particle A tiny speck of matter such as carbon dioxide and within a cell that supply energy that can have velocity, position, methane that absorb energy to the cell. mass, and charge. reflected by Earth’s surface, stopping it from escaping Molecule The smallest unit Pauli exclusion principle into space. of a compound that has its In quantum physics, the principle chemical properties, made of that two fermions (particles with Heat death A possible end state two or more atoms. mass) cannot have the same for the universe in which there are quantum state in the same point no temperature differences across Momentum A measure of the in space-time. space, and no work can be done. force required to stop a moving object. It is equal to the product of Periodic table A table containing Heliocentrism A model of the the object’s mass and its velocity. all the elements arranged according universe with the Sun at its center. to their atomic number. Multiverse A hypothetical set of Higgs boson A subatomic particle universes in which every possible Photoelectric effect The associated with the Higgs field, event happens. emission of electrons from the whose interaction with matter surfaces of certain substances gives matter its mass. Natural selection The process when light hits them. by which characteristics that Hydrocarbon A chemical whose increase an organism’s chances Photon The particle of light that molecules contain one of many of reproducing are passed on. transfers the electromagnetic force possible combinations of hydrogen from one place to another. and carbon atoms. Neutrino An electrically neutral subatomic particle that has a Photosynthesis The process by Ion An atom, or group of atoms, very small mass. Neutrinos which plants use the energy of the that has lost or gained one or can pass right through Sun to make food from water and more of its electrons to become matter undetected. carbon dioxide. electrically charged. Neutron An electrically neutral Pi (π) The ratio between the Ionic bond A bond between two subatomic particle that forms part circumference of a circle and its atoms in which they exchange an of an atom’s nucleus. A neutron is diameter. It is roughly equal to electron to become ions. The ions’ made of one up-quark and two 22/7, or 3.14159. opposite electric charge attracts down-quarks. them to each other. Pi bond A covalent bond in which Nucleus The central part of an the lobes of the orbitals of two or Leptons Fermions that are atom, comprising protons and more electrons overlap sideways, affected by all of the four neutrons. The nucleus contains rather than directly, between the fundamental forces except almost all of an atom’s mass. atoms involved. the strong nuclear force. Optics The study of vision and Plate tectonics The study of Magnetism A force of attraction the behavior of light. continental drift and the way in or repulsion exerted by magnets. which the ocean floor spreads. Magnetism is produced by Organic chemistry The chemistry magnetic fields or by the property of compounds containing carbon. Polarized light Light in which the of magnetic moment of particles. waves all oscillate in just one plane. Parallax The apparent movement Mass A property of an object of objects at different distances Polymer A substance whose that is a measure of the force relative to each other when an molecules are in the shape of long required to accelerate it. observer moves. chains of subunits called monomers.

GLOSSARY 343 Positron The antiparticle Respiration The process by which Superposition In quantum counterpart of an electron, with organisms take in oxygen and use physics, the principle that, until the same mass but a positive it to break down food into energy it is measured, a particle such as electric charge. and carbon dioxide. an electron exists in all its possible states at the same time. Pressure A continual force Salt A compound formed from the pushing against an object. The reaction of an acid with a base. Thermodynamics The branch of pressure of gases is caused by physics that deals with heat and the movement of their molecules. Sigma bond A covalent bond its relation to energy and work. formed when the orbitals of Proton A particle in the nucleus electrons meet head-on between Transpiration The process of an atom that has positive charge. atoms. It is a relatively strong bond. by which plants emit water vapor A proton contains two up-quarks from the surface of their leaves. and one down-quark. Singularity A point in space-time with zero length. Uncertainty principle A property Quantum electrodynamics of quantum mechanics that means (QED) A theory that explains the Space-time The three dimensions that the more accurately certain interaction of subatomic particles of space combined with one qualities, such as momentum, are in terms of an exchange of photons. dimension of time to form a measured, the less is known of single continuum. other qualities such as position, Quantum mechanics The branch and vice versa. of physics that deals with the Special relativity The result of interactions of subatomic particles considering that both the speed Uniformitarianism The in terms of discrete packets, or of light and the laws of physics are assumption that the same laws quanta, of energy. the same for all observers. Special of physics operate at all times in relativity removes the possibility of all places across the universe. Quark A subatomic particle an absolute time or absolute space. that protons and neutrons are Valency The number of chemical made from. Species A group of similar bonds that an atom can make with organisms that can breed with one other atoms. Radiation Either an another to produce fertile offspring. electromagnetic wave or a Velocity A measure of an object’s stream of particles emitted Spin A quality of subatomic speed and direction. by a radioactive source. particles that is analogous to angular momentum. Vitalism The doctrine that living Radioactive decay The matter is fundamentally different process in which unstable Standard model The theoretical from nonliving matter. Vitalism atomic nuclei emit particles or framework of particle physics in posits that life depends on a special electromagnetic radiation. which there are 12 basic fermions “vital energy.” It is now rejected by —six quarks and six leptons. mainstream science. Redshift The stretching of light emitted by galaxies moving String theory A theoretical Wave An oscillation that travels away from Earth, due to the framework of physics in which through space, transferring energy Doppler effect. This causes pointlike particles are replaced from one place to another. visible light to move toward by one-dimensional strings. the red end of the spectrum. Weak nuclear force One of Strong nuclear force One of the the four fundamental forces, Refraction The bending of four fundamental forces, which which acts inside an atomic electromagnetic waves as they binds quarks together to form nucleus and is responsible for move from one medium to another. neutrons and protons. beta decay.

344 INDEX Numbers in bold indicate main entries. Arndt, Markus 320 Becquerel, Henri 192, 208–09, 210 Arrhenius, Svante 294 Béguyer de Chancourtais, A 177, 179 A artificial intelligence 268, 286–91 behavior, innate and learned 201, 249 Aryabhata 330 Beijerinck, Martinus 196–97 Abell, George 250 atmosphere 14, 15, 79, 123, 274–75, Bell, Jocelyn 248, 339 abiogenesis 156–59 Bell, John 285 acceleration 42–43, 65–67, 218, 220 294, 315 benzene 109, 163–65, 258 Adams, John Couch 87 atomic bomb 201, 262, 264–65 Berlesi, Antonio 53 adenosine triphosphate (ATP) 300 atomic clocks 216, 221 Bernard, Claude 335 Agassiz, Louis 108, 109, 128–29 atomic number 179, 212 Berners-Lee, Tim 339 air 18, 21, 79, 82–83, 84, 112–13, 223 atomic shells 212–13, 228, 230–31, 258 Bernoulli, Daniel 24, 46, 72, 139, 333 atomic theory 206–13, 228 Berthollet, Claude Louis 105 speed of light in 108, 136, 137 atomic weights 15, 108, 112–13, 162, Berti, Gasparo 47 air pressure 32, 46–49, 112, 152, 153, 154 Berzelius, Jöns Jakob 105, 108, 119, air pumps 47–48, 49 176–79, 208 air resistance 42, 43, 65, 66 atoms 56, 105, 139 124, 125, 162 Airy, George 102 beta decay 194, 292 Akiba, Tomoichiro 318, 319 arrangement of 125 beta particles 194, 210 Albert I, Prince of Monaco 81 bonding 119, 124, 162–65, 201, 256–59 Bethe, Hans 270, 273 alchemy 14, 19, 48, 79 nuclear model 192 Big Bang 15, 201, 241, 242, 243, 244–45, algorithms 19, 252, 253 splitting 201, 208, 260–65 Alhazen 12, 13, 19, 28–29, 43, 45, 50 structure of 15, 179, 192, 193, 201, 250, 293, 299, 305, 310–14 alkali metals 114, 119, 176, 178 binary stars 108, 127 alleles 171 206–13, 228, 229–31 biomes 134 alloys 24 Avicenna 98 Biot, Jean-Baptiste 122 alpha helix 280, 281, 282 Avogadro, Amedeo 105, 112, 113 birds, evolution of 109, 172–73 alpha particles 12, 194, 210, 211, 213, 231 al-Biruni 98 Alpher, Ralph 244, 245 B black bodies 202, 203–05 amino acids 156, 159, 275, 278, 283 black holes 15, 88–9, 201, 248, 251, 264, Ampère, André-Marie 120, 121, 183, Baade, Walter 248, 251 Babbage, Charles 334 269, 313, 314 184, 334 Bacon, Francis 12, 28, 29, 32, 45, 222 Black, Joseph 72, 76–77, 78, 82, 122 Anaximander of Miletus 23 Bacon, Roger 56 Blaese, Michael 322 Anaximenes 21 bacteria 33, 57, 158, 159, 196, 197, 278, Bloch, Eugène 337 Anderson, Carl 246, 247 blood, circulation of 14, 331 Anderson, William French 322–23 279, 300, 301, 318, 319, 324, 325 blueshift 127, 239, 327 Andromeda nebula 240 Bada, Jeffrey 27 Bode, Johann Elert 87 angular momentum 80, 231, 311 Baekeland, Leo 140–41 Bohm, David 233, 337 animal electricity 92, 93, 114 Bakewell, Robert 115 Bohr, Niels 13, 176, 212, 228, 229, 230, Anning, Mary 15, 108, 109, 116–17 Ballot, Christophorus Buys 126, 127 antibiotics, resistance to 318, 319 Banks, Joseph 93, 94–95 232, 234, 235, 256, 263, 284, 285, 337 antimatter 235, 246–47, 269, 307 barium 263 Boltwood, Bertram 100 antiparticles 208, 246, 304, 307, 314 barometers 32, 47–49, 152, 154 Boltzmann, Ludwig 139, 202, 204–05 Archimedes 18, 24–25, 36 bases 278, 279, 281, 282, 283, 325 bonds, chemical 119, 124, 162, 162–63, Aristarchus of Samos 18, 22, 36, 37, 38 Bateson, William 168, 170, 171 Aristotle 12, 18, 21, 28, 32, 33, 36, 42, batteries 13, 15, 73, 93–95, 108, 119, 120 201, 254–59 Bauhin, Caspar 60 Bonnet, Charles 85 45, 48, 53, 60, 64–65, 74, 132, 156 Beaufort, Francis 152, 153 Bonpland, Aimé 133, 135 Becher, Johann Joachim 84 Born, Max 230, 232, 234, 246, 262, 264, 337 Becker, Herbert 213 Bose, Satyendra Nath 231 bosons 231, 272, 292–93, 298–99, 304, 305, 306, 307, 311, 312 botany 18, 33, 61, 168–71 Bothe, Walther 213

INDEX 345 Bouguer, Pierre 102 248, 314 Cruickshank, William 95 Bouvard, Alexis 87 chaos theory 296–97, 316 CT (computed tomography) scans 187 Boveri, Theodor 224–25, 271, 279 Chargaff, Edwin 281 Ctesibius 18, 19 Boyle, Robert 14, 21, 32, 46–49, 76, 78, Charles, Jacques 78 Curie, Marie (Sklodowska) 109, Charpentier, Jean de 128 176 Châtelet, Émilie du 138 190–95, 209, 210 Bradley, James 58 Chatton, Edouard 300 Curie, Pierre 192, 193, 209, 210 Bragg, Sir Lawrence 2 78 Chew, Geoffrey 310 Curl, Robert 320, 321 Brahe, Tycho 32, 39, 40–41, 59 China, ancient 18–19, 26–29 currents Brahmagupta 19, 331 chloroplasts 85, 300, 301 Brand, Hennig 332 chromosomes 15, 168, 170–71, 200, convection 222, 223 Brandt, Georges 114 ocean 81, 83, 126 branes 310, 312, 313 224–25, 271, 278, 282, 319, 324, 325 Curtis, Heber D. 240 Branly, Édouard 336 chronometers 59 Cuvier, Georges 55, 74, 115, 118, 129, 145 Branson, Herman 280 cladistics 74, 75 cyclonic patterns 153–54 Brongniart, Alexandre 55, 115 Clapeyron, Émile 122 cystic fibrosis 322, 323 Brout, Robert 298, 299 Clausius, Rudolph 138 Brown, Robert 46, 104, 139 Clements, Frederic 134 D Bruni, Giordano 284 climate change 108, 109, 128, 129, 135, buckeyballs 321 Daguerre, Louis 334 Buckland, William 129 294–95 Dalton, John 14–15, 21, 80, 105, 108, Buffon, Georges-Louis Leclerc, Comte de clocks 18, 19, 32, 51, 59, 89, 216, 221 cloning 15, 269, 326 112–13, 162, 176, 208 72, 73, 98–99, 100, 333 cluster galaxies 201, 250–51 dark energy 238, 245, 250, 251 butterfly effect 296–97 Cockcroft, John 262, 305 dark matter 15, 201, 245, 250, 251 Colladon, Jean-Daniel 335 Darwin, Charles 15, 23, 53, 60, 73, C color charge 272, 307, 311 combustion 14, 72, 79, 82, 83, 84 74, 100, 104, 109, 118, 129, 135, Callendar, Guy 294 comets 12, 13, 40–41, 68, 86, 87 142–49, 152, 168, 172, 225, 249, camera obscura 29 compounds 72, 105, 112, 114, 119, 162–65 274, 300, 315, 319 Camerarius, Rudolph 104 computer science 15, 252–53, 269, Darwin, Erasmus 144, 145 cancer 186, 193, 195, 321 Davy, Humphry 78, 79, 92, 95, 114, 119, Cannizzaro, Stanislao 162, 176 288–91, 317 176 carbon compounds 163–65, 256–58, 257 condensation 21, 76, 77, 79 Dawkins, Richard 249, 339 carbon dioxide 72, 76, 77, 78, 82, 83, 85, conductors, electrical 321 de Bary, Anton 300 conservation of energy 138 de Broglie, Louis 202, 229–30, 232, 233, 257, 258, 268, 294–95 consistent histories 233 234, 272 carbon-14 194–95 continental drift 200, 222–23 De Forest, Lee 252 carbon-60/carbon-70 320–21 Cook, Captain James 52 De la Beche, Henry 116, 117 Carlisle, Anthony 92, 95 Copenhagen interpretation 232–33, de Sitter, Willem 221, 243 Carnot, Sadi 122, 138, 334 de Vries, Hugo 168, 170, 224 Carson, Rachel 132, 134, 135 234, 235, 285 decoherence 284, 285 Cassini, Giovanni 58, 59 Copernicus, Nicolaus 14, 26, 32, Delambre, Jean-Baptiste 58 cathode rays 186–87, 209, 304 Democritus 21, 105, 112, 208 Cavendish, Henry 72, 76, 78–9, 82, 88, 34–39, 40, 52, 64, 238 Descartes, René 1 2, 13, 45, 46, 50, 332 Corey, Robert 280 diamonds 257 89, 92, 95, 102, 188 Coriolis, Gaspard-Gustave de 80, 126 Dicke, Robert 245 cells 54, 56, 170, 322,323 Correns, Carl 168, 170 diffraction 50, 51, 187, 229, 232, 256, cosmic dust 320 279, 280 division 224, 278–79, 300, 301 cosmic microwave background dimensions, extra 269, 311, 312, 313 symbiosis 300–01 dinosaurs 108, 109, 116–17, 172–73 Cepheid variable stars 239–40, 241 radiation (CMBR) 242, 244, 245 Dirac, Paul 201, 228, 231, 234, 246–47, Cesalpino, Andrea 60 cosmic rays 304 248, 269, 272 Chadwick, James 192, 193, 213, 304 cosmological constant 216, 243 DNA 75, 171, 172, 269, 274, 300, 301, Chamberland, Charles 197 Coulson, Charles 256 318, 319, 322, 324–25 Chandrasekhar, Subrahmanyan 201, Couper, Archibald 124, 162, 163 covalent bonds 119, 256, 257, 258, 259 Crick, Francis 224, 268, 271, 276–83, 318, 324, 326 Croll, James 128 Crookes, William 186

346 INDEX structure of 15, 169, 186, 187, 224, 229, 230, 231, 232, 234, 246, 256, Ferrel, William 80, 126 268, 271, 276–83, 324, 326 259, 292, 304, 307, 317 fertilization 73, 104, 148, 169, 171, 224, electropositivity 256, 259 Döbereiner, Johann 176 electroweak theory 268, 269, 272, 273, 283, 326 Dobzhansky, Theodosius 144 292, 293, 299 Feynman, Richard 182, 246, 268, 269, Donné, Alfred 137 elements Doppler, Christian 108, 127, 241 atomic theory of 15, 105, 112–13, 162 272–73, 310 Doppler effect 108, 241, 327 classification of 176–79 fields, force 298, 299 Dossie, Robert 105 combination of 72, 105, 162–63 fire 18, 21, 84 double helix 224, 271, 278, 279, 281, new 15, 114, 178, 268, 270 fission, nuclear 194, 262, 263, 264, 265 Elsasser, Walter Maurice 44 FitzRoy, Robert 150–55 282–83, 326 Elton, Charles 134–5 Fizeau, Hippolyte 58, 108, 127, 137 Empedocles 13, 18, 21 Flemming, Walther 170, 278 E endosymbiosis 268, 269, 300, 301 fluids 24–25, 72, 333 Engelman, Théodore 85 Folger, Timothy 81 Earth 26–27, 32, 36–39, 40, 64, 66, 67 Englert, François 298, 299, 338 food chain 134–35 age of 73, 96–101 entropy 138, 202, 203–05 forces 42, 43, 64–9, 307 atmosphere 15, 79, 123, 274–75, 294 environment circumference 19, 22 damage to/conservation of 135, fundamental 251, 269, 273, 292–93, continental drift 222–23 294–95, 315 306, 310, 313 core 188, 189 and evolution 118, 133, 147, 149, 315 density 73, 79, 89, 102–03, 188 Epicurus 23 fossil fuels 115, 294, 295 magnetic field 14, 44, 223 epigenetics 268 fossils 15, 74, 98, 100, 108, 109, 115, rotation of 44, 73, 126 Eratosthenes 18, 19, 22 erosion 99 116–17, 118, 145, 146, 172–73, earth (element) 18, 21 Esmark, Jens 128 222–23, 270, 319 earth science 73, 102, 128–29, 222–23 ether 13, 46, 49, 50, 51, 136, 185, 217, Foucault, Léon 108, 126, 136–37 earthquakes 89, 188–89 218, 219, 220 four roots/humors 13, 18, 21 eclipses 18, 20, 26, 27, 32, 58–59, 221 ethology 249 Fourier, Joseph 122–23, 294 ecology 108, 109, 113, 132–35, 315 ethylene 257, 258 Fowler, Ralph 247, 248 ecosystems 134, 315 Euclid 28, 29 Fracastoro, Girolamo 157 Eddington, Arthur 221, 270 eukaryotic cells 300, 301 fractals 316 Edison, Thomas 121 evaporation 77 Frankland, Edward 162, 256 Einstein, Albert 50, 64, 69, 88–89, 110, event horizon 88, 89, 314 Franklin, Benjamin 72, 73, 81, 92 Everett, Hugh, III 233, 268, 269, Franklin, Edward 124 111, 139, 182, 200, 202, 205, 212, 284–85, 317 Franklin, Rosalind 186, 280, 281, 283 214–21, 228, 231, 232, 235, 242–43, evolution 23, 60, 73, 74, 75, 109, 118, Fresnel, Augustin 334 244, 262, 264, 304, 310, 317 133, 142–49, 168, 172–73, 224, 268, friction 42, 65 Eldredge, Niles 144, 339 274, 300, 315, 318, 319, 325 Friedmann, Alexander 243 electricity 15, 73, 90–95, 108, 114, 119, exoplanets 15, 127, 327 Frisch, Otto 263 120–21, 138, 182–85, 186, 192, 194, extinction 116, 145, 149 fullerenes 320, 321 262, 292 Füschel, Georg 115 electrochemical dualism 119 F fusion, nuclear 194, 270 electrodynamics 184, 218 electrolysis 114, 119 falling bodies 12, 32, 42–43, 45, 66 G electromagnetic radiation 50, 194, Faraday, Michael 15, 92, 108, 114, 120, 211–13, 219, 247 Gaia hypothesis 132, 301, 315 electromagnetic waves 50, 108, 120, 121, 182–83, 184, 186 galaxies 89, 127, 201, 238–41, 242, 245, 136, 182–85, 200, 217, 292 Fatou, Pierre 316 electromagnetism 15, 108, 109, 120–21, Fawcett, Eric 140 250–51 182–85, 201, 218, 219, 269, 272, Fermi, Enrico 231, 246, 265, 292 Galen 14 273, 292, 299, 306, 307, 310 fermions 231, 246–47, 306, 307, 311, 312 Galilei, Galileo 12, 13, 32, 36, 39, electronegativity 259 electrons 111, 119, 164, 187, 192, 200, 42–43, 44, 45, 48, 58, 64, 65, 80 208, 209–10, 211–12, 216–17, 228, Galle, Johann 64 Galvani, Luigi 92, 93, 95, 114, 324 gamma rays 194, 195, 210 Gamow, George 244

INDEX 347 gases 14, 49, 274, 275 H Hubble, Edwin 127, 200, 201, 236–41, isolation of 72, 76, 78–79, 82–3 242, 243, 250 kinetic theory of 46, 49, 72, 139 Haber, Fritz 336 Hadley, George 72, 73, 80, 126 Huffman, Don 320 Gassendi, Pierre 52 hadrons 304, 306, 307, 310 Huggins, William 127, 270 gauge bosons 272, 292, 295, 306, Haeckel, Ernst 74, 132, 315 human genome 15, 268–69, 271, 278, Hahn, Otto 208, 262–63 307 Haldane, J. B. S. 274, 275 283, 324, 325 Gay-Lussac, Joseph Louis 162 Hales, Stephen 72, 333 Humason, Milton 241 Geiger, Hans 211 half-life, radioactive 194 Humboldt, Alexander von 108, 109, Gell-Mann, Murray 269, 293, 302–07 Halley, Edmond 12, 67, 68, 80, 102, 103 gene therapy 15, 283, 322–3 Han, Moo-Young 272 130–35, 315 general relativity 220–21, 242–3, 247, Harrison, John 59 hurricanes 153 Harvey, William 14, 53, 157, 331 Hutton, James 55, 73, 96–101, 146 269, 313 Hawking, Stephen 88, 89, 269, 314 Huxley, T. H. 109, 149, 159, 172–73 genes 170, 171, 224, 225, 249, 271, Hawkins, B. Waterhouse 116, 117 Huygens, Christiaan 32, 50–51, 110, 136 heat 15, 76–77, 79, 122–23, 138 Hyatt, John 140, 141 278–83, 318–19 heat death 245, 338 hydrocarbons 141, 163–65, 256–58 horizontal transfer 268, 269, 318–19 Heaviside, Oliver 185 hydrogen 72, 76, 78–79, 82, 162–63, genetic engineering 283, 319 Heisenberg, Werner 15, 200, 201, 228, genetic recombination 268, 271 213, 228, 230, 234, 270, 292, 304 genetics 60, 109, 118, 149, 168–71, 230, 232, 234–35, 246, 272, 284, 285 heliocentrism 14, 18, 32, 38–39, 40, 41, IJ 224–25, 249, 268, 271, 278–83, 301, 318–19, 326 43, 52, 64 Ibn Khaldun 23 genome sequences 15, 271, 278, 283, helium 79, 270, 292 Ibn Sahl 28 319, 324, 325 Helmholtz, Hermann von 138, 270 Ibn Sina 42, 116, 331 geocentrism 13, 14, 32, 36, 40, 41 Helmont, Jan Baptista von 85, 156–57 ice ages 108, 109, 129 geography 22 Hennig, Willi 74, 75 imprinting 249 geology 15, 33, 44, 55, 73, 96–101, 115, Henry, Joseph 120, 121, 152 India, ancient 19 188–89, 223 heredity see inheritance infection 157, 158, 159, 196–97, 323 germs 157, 159, 196 Herman, Robert 245 infrared 87, 88, 89, 108, 203, 251 Gibson, Reginald 140 Hero 18 Ingenhousz, Jan 72, 73, 85 Gilbert, William 14, 32, 44, 120 Herodotus 20, 132 inheritance 168–71, 200, 224–25, 249, glaciation 128–29 Herschel, William 68, 86–87, 108 Glashow, Sheldon 268, 272, 292–93 Hertz, Heinrich 184–85, 216 271, 278, 279, 322, 324 global warming 135, 294–95 Hertzsprung, Ejnar 240 inorganic chemicals 108, 124, 125 gluons 299, 306, 307 Hess, Harry 222 insects 33, 53, 73, 104 Goldstein, Eugen 187 Hewish, Anthony 248 interference 111 Gondwanaland 223 Higgs, Peter 269, 293, 298–99 ionic bonding 119, 258–59 Gosling, Raymond 281 Higgs boson 13, 269, 298–99, 304, 305, ions 119, 258, 259 Gould, John 146 isomers 125, 164 Gould, Stephen Jay 144, 339 306, 307 isotopes 193–95, 263, 264, 275 gravitational lensing 220, 221 Hilbert, David 252 Ivanovsky, Dmitri 196, 197 gravity 14, 24, 33, 41, 43, 62–69, 73, Hipparchus 19, 20, 26 Jabir Ibn Hayyan (Geber) 112, 331 88–89, 102, 103, 183, 200, 214–21, Hiroshima 265 Jablonka, Eva 118 248, 269, 270, 273, 292, 293, 306, histones 279 Janssen, Hans and Zacharius 54 310, 311, 313, 314 Hittorf, Johann 186–87 Jeans, Sir James 204, 205 Greeks, ancient 12, 13, 18, 20–22, Holmes, Arthur 101, 222 Jeffreys, Harold 188, 189 24–25, 60, 132, 292 Hooke, Robert 14, 33, 45, 48, 50, 54, 56, Jones, David 320 Greenberg, Oscar 272 Jönsson, Claus 110, 111 Greenblatt, Richard 288 57, 67–68, 69 Jordan, Pascual 230, 234, 246 greenhouse effect/gases 294–95, 315 Hooker, Joseph 144, 274 Joule, James 76, 138 Gregorian calendar reform 39 horizontal gene transfer (HGT) 318–19 Julia, Gaston 316 Gregory, James 52 Horrocks, Jeremiah 32, 40, 52 Jupiter 32, 36, 39, 43, 58–59, 127, 136 Griffith, Frederick 318–19 Hoyle, Fred 244, 268, 270 Jurassic period 116–17, 172 Grosseteste, Robert 28 Guericke, Otto von 46, 47–48 Gulf Stream 72, 73, 81 Guth, Alan 242

348 INDEX K life 159, 268, 274–75, 315 matter waves 229–30, 234, 235 stages of development 33, 53 Maury, Matthew 81, 153 Kaluza, Theodor 311 synthetic 268–69, 269, 324–25 Maxwell, James Clerk 50, 108, 109, 120, Kant, Immanuel 120, 238 Karplus, Martin 338 light 28–29, 88–89, 111, 127, 180–85, 136, 139, 180–85, 217, 247, 292 Keeling, Charles 268, 294–95 220, 221, 246, 273, 314 Mayer, Adolf 196 Kekulé, August 15, 109, 119, 124, Mayor, Michel 327 quantizing 202, 216–17, 218, 228, 234 Mayr, Ernst 144 160–65, 256, 258 speed of 15, 33, 50, 51, 58–59, 88–89, Meitner, Lise 208, 263 Kelvin, Lord 98, 100, 109, 335 MENACE 288–91 Kepler, Johannes 26, 28, 32, 36, 39, 108, 136–37, 200, 216, 217–19, 311 Mendel, Gregor 15, 109, 118, 149, wave-particle duality 15, 108, 111, 40–41, 44, 52, 64, 67 166–71, 224, 225, 271, 279, 324 Kidwell, Margaret 318 200, 202, 228–29, 230, 234, 284, 285 Mendeleev, Dmitri 21, 109, 112, 114, kinetic theory 24, 46, 49, 72, 139 waves 33, 50–51, 108, 110–11, 127, Kirschhoff, Gustav 203, 204 162, 174–79, 306 Klein, Oscar 311 136, 182–83, 228–29, 241 Mercury 36, 52, 69, 221 Koch, Robert 156, 159, 196, 197 lightning 73, 92 Mereschkowsky, Konstantin 300 Kölliker, Albert von 56 Lindeman, Raymond 135 Mersenne, Marin 332 Kölreuter, Josef Gottlieb 104, 168 Linnaeus, Carl 60, 72, 74–75, 104, 116 Messier, Charles 86 Kossel, Walther 119 Lippershey, Hans 54 metals 95, 114, 176, 178 Krätschmer, Wolfgang 320 Locke, John 60 metamorphosis 53 Kroto, Harry 320–21 longitude 58–59, 103 meteorites 101, 275 krypton 263 loop quantum gravity (LQG) 310, 313 methane 257, 258 Lorentz, Hendrik 219, 229 Meyer, Lothar 176, 179 L Lorenz, Edward 296–97 Michell, John 88–89, 314 Lorenz, Konrad 201, 249 Michelson, Albert 136, 218 Lamarck, Jean-Baptiste 23, 109, 118, Lovelock, James 132, 301, 315 Michie, Donald 286–91 144, 145, 147 Lyell, Charles 99, 128, 129, 146–47, 148 microbes 156–59, 300, 301, 315, 319 microbiology 159, 196–97 Lamb, Marion 118 M microscopes 33, 54, 56–57, 157, 158, Laplace, Pierre-Simon 88, 122 Large Hadron Collider 268–69, 298–99 M-theory 312–13 170, 197, 268, 300 Lavoisier, Antoine 14, 72, 73, 78, 82, 83, MacArthur, Robert 135 microscopic life 14, 33, 56–57, 158 McCarthy, John 288 Miescher, Friedrich 278, 279 84, 105, 122, 124 McClintock, Barbara 224, 268, 271 Milankovic, Milutin 128 Le Verrier, Urbain 64, 86, 87 Magellanic Clouds 239 Milky Way 201, 238, 239, 240, 251, 327 Leavitt, Henrietta 238, 239–40 magnetism 14, 32, 44, 89, 92, 102, 108, Miller, Stanley 156, 159, 268, 274–75 Lederberg, Joshua 318, 319 Millikan, Robert Andrews 110, 217 Leeuwenhoek, Antonie van 33, 54, 120–21, 182–85, 292, 299 Mills, Robert 292 Malthus, Thomas 73, 147, 148 Milne, John 188 56–57, 158 Mandelbrot, Benoît 296, 316 Minkowski, Hermann 221 Lehmann, Inge 188, 189 Manhattan Project 201, 260–65, 273, 275 Minsky, Marvin 338 Lehmann, Johann 115 Manin, Yuri 269, 317 mitochondria 300, 301 Leibnitz, Gottfried 33, 69, 332 many-worlds interpretation (MWI) 233, Mohorovicic, Andrija 188 Lemaître, Georges-Henri 201, 238, Moissan, Henri 336 268, 284, 285 molecules 15, 105, 113, 139, 162, 256, 242–45 Marcy, Geoff 327 Leonardo da Vinci 55, 118 Margulis, Lynn 268, 269, 300–01, 315 257, 258, 320–21 leptons 306, 307 Maricourt, Pierre de 44 Montgolfier brothers 78 Levene, Phoebus 278, 279 Mars 32, 36, 315 Moon 26–27, 42, 64, 66, 103 Lewis, Gilbert 119, 256 Marsden, Ernest 192, 193, 211 Morgan, Thomas Hunt 168, 200, Lexell, Anders Johan 87 Maskelyne, Nevil 73, 87, 102–03 Liebig, Justus von 124–25, 165, 335 mass, conservation of 84 224–25, 271, 279, 324 mass-energy equivalence 200, 219–20, Morley, Edward 218 Moseley, Henry 176, 179 244, 262, 270, 304 motion, laws of 14, 33, 42–43, 64–69, 72 matrix mechanics 230, 234, 246 motors, electric 15, 108, 121, 182 matter 208, 216, 246–47, 292, 307 Müller, Erwin Wilhelm 56 Mulligan, Richard 322 mycoplasma 325