Stephen Hawking

About Stephen Hawking

Stephen William Hawking CH CBE FRS FRSA (born 8 January 1942) is an English theoretical physicist, cosmologist, author and Director of Research at the Centre for Theoretical Cosmology within the University of Cambridge. Among his significant scientific works have been a collaboration with Roger Penrose on gravitational singularity theorems in the framework of general relativity, and the theoretical prediction that black holes emit radiation, often called Hawking radiation. Hawking was the first to set forth a cosmology explained by a union of the general theory of relativity and quantum mechanics. He is a vocal supporter of the many-worlds interpretation of quantum mechanics.

Hawking is an Honorary Fellow of the Royal Society of Arts, a lifetime member of the Pontifical Academy of Sciences, and a recipient of the Presidential Medal of Freedom, the highest civilian award in the United States. Hawking was the Lucasian Professor of Mathematics at the University of Cambridge between 1979 and 2009.

Hawking has achieved success with works of popular science in which he discusses his own theories and cosmology in general; his A Brief History of Time stayed on the British Sunday Times best-sellers list for a record-breaking 237 weeks. Hawking has a motor neuron disease related to amyotrophic lateral sclerosis (ALS), a condition that has progressed over the years. He is almost entirely paralysed and communicates through a speech generating device. He married twice and has three children.

Early life and education

Stephen Hawking was born on 8 January 1942 to Frank and Isobel Hawking. Despite their families' financial constraints, both parents attended the University of Oxford, where Frank studied medicine and Isobel, Philosophy, Politics and Economics. The two met shortly after the beginning of the Second World War at a medical research institute where she was working as a secretary and he as a medical researcher. They lived in Highgate, but as London was under attack in those years, his mother went to Oxford to give birth in greater safety. Stephen has two younger sisters, Philippa and Mary, and an adopted brother, Edward. He began his schooling at the Byron House School; he later blamed its "progressive methods" for his failure to learn to read while at the school.

In 1950, when his father became head of the division of parasitology at the National Institute for Medical Research, Hawking and his family moved to St Albans, Hertfordshire. The eight-year-old Hawking attended St Albans High School for Girls for a few months; at that time, younger boys could attend one of the houses. In St Albans, the family were considered highly intelligent and somewhat eccentric; meals were often spent with each person silently reading a book. They lived a frugal existence in a large, cluttered, and poorly maintained house, and travelled in a converted London taxicab. During one of Hawking's father's frequent absences working in Africa, the rest of the family spent four months in Majorca visiting his mother's friend Beryl and her husband, the poet Robert Graves.

On their return to England, Hawking attended Radlett School for a year and from September 1952, St Albans School. The family placed a high value on education. Hawking's father wanted his son to attend the well-regarded Westminster School, but the 13-year-old Hawking was ill on the day of the scholarship examination. His family could not afford the school fees without the financial aid of a scholarship, so Hawking remained at St Albans. A positive consequence was that Hawking remained with a close group of friends with whom he enjoyed board games, the manufacture of fireworks, model aeroplanes and boats, and long discussions about Christianity and extrasensory perception. From 1958, and with the help of the mathematics teacher Dikran Tahta, they built a computer from clock parts, an old telephone switchboard and other recycled components. Although at school he was known as "Einstein," Hawking was not initially successful academically. With time, he began to show considerable aptitude for scientific subjects, and inspired by Tahta, decided to study mathematics at university. Hawking's father advised him to study medicine, concerned that there were few jobs for mathematics graduates. He wanted Hawking to attend University College, Oxford, his own alma mater. As it was not possible to read mathematics there at the time, Hawking decided to study physics and chemistry. Despite his headmaster's advice to wait until the next year, Hawking was awarded a scholarship after taking the examinations in March 1959.

University

Hawking began his university education at the University of Oxford in October 1959 at the age of 17. For the first 18 months, he was bored and lonely: he was younger than many other students, and found the academic work "ridiculously easy." His physics tutor Robert Berman later said, "It was only necessary for him to know that something could be done, and he could do it without looking to see how other people did it." A change occurred during his second and third year when, according to Berman, Hawking made more effort "to be one of the boys". He developed into a popular, lively and witty college member, interested in classical music and science fiction. Part of the transformation resulted from his decision to join the college Boat Club, where he coxed a rowing team. The rowing trainer at the time noted that Hawking cultivated a daredevil image, steering his crew on risky courses that led to damaged boats. Hawking has estimated that he studied about 1,000 hours during his three years at Oxford. These unimpressive study habits made sitting his Finals a challenge, and he decided to answer only theoretical physics questions rather than those requiring factual knowledge. A first-class honours degree was a condition of acceptance for his planned graduate study in cosmology at the University of Cambridge. Anxious, he slept poorly the night before the examinations and the final result was on the borderline between first- and second-class honours, making a viva necessary. Hawking was concerned that he was viewed as a lazy and difficult student, so when asked at the oral examination to describe his future plans, he said, "If you award me a First, I will go to Cambridge. If I receive a Second, I shall stay in Oxford, so I expect you will give me a First." He was held in higher regard than he believed: as Berman commented, the examiners "were intelligent enough to realise they were talking to someone far cleverer than most of themselves." After receiving a first-class BA (Hons.) degree, and following a trip to Iran with a friend, he began his graduate work at Trinity Hall, Cambridge, in October 1962.

Hawking's first year as a doctoral student was difficult. He was initially disappointed to find that he had been assigned Dennis William Sciama as a supervisor rather than Fred Hoyle, and he found his training in mathematics inadequate for work in general relativity and cosmology. He also struggled with his health. Hawking had experienced increasing clumsiness during his final year at Oxford, including a fall on some stairs and difficulties when rowing. The problems worsened, and his speech became slightly slurred; his family noticed the changes when he returned home for Christmas and medical investigations were begun. The diagnosis of motor neurone disease came when Hawking was 21. At the time, doctors gave him a life expectancy of two years. After his diagnosis, Hawking fell into a depression; though his doctors advised that he continue with his studies, he felt there was little point. At the same time, however, his relationship with Jane Wilde, friend of his sister, and whom he had met shortly before his diagnosis, continued to develop. The couple were engaged in October 1964. Hawking later said that the engagement "gave him something to live for." Despite the disease's progression—Hawking had difficulty walking without support, and his speech was almost unintelligible—he now returned to his work with enthusiasm. Hawking started developing a reputation for brilliance and brashness when he publicly challenged the work of Fred Hoyle and his student Jayant Narlikar at a lecture in June 1964.

When Hawking began his graduate studies, there was much debate in the physics community about the prevailing theories of the creation of the universe: the Big Bang and the Steady State theories. Inspired by Roger Penrose's theorem of a spacetime singularity in the centre of black holes, Hawking applied the same thinking to the entire universe, and during 1965 wrote up his thesis on this topic. There were other positive developments: Hawking received a research fellowship at Gonville and Caius College, and he and Jane were married on 14 July 1965. He obtained his D.Phil. degree in March 1966, and his essay entitled "Singularities and the Geometry of Space-Time" shared top honours with one by Penrose to win that year's Adams Prize.

Later life and career

1966–1975

The first years of marriage were hectic: Jane lived in London during the week as she completed her degree and they travelled to the United States several times for conferences and physics-related visits. The couple had difficulty finding housing that was within Hawking's walking distance to the Department of Applied Mathematics and Theoretical Physics (DAMTP). Jane began a Ph.D. program, and a son, Robert, was born in May 1967. In his work, and in collaboration with Penrose, Hawking extended the singularity theorem concepts first explored in his doctoral thesis. This included not only the existence of singularities but also the theory that the universe might have started as a singularity. Their joint essay was the runner-up in the 1968 Gravity Research Foundation competition. In 1970 they published a proof that if the universe obeys the general theory of relativity and fits any of the models of physical cosmology developed by Alexander Friedmann, then it must have begun as a singularity.

During the late 1960s, Hawking's physical abilities declined once more: he began to use crutches and ceased lecturing regularly. As he slowly lost the ability to write, he developed compensatory visual methods, including seeing equations in terms of geometry. The physicist Werner Israel later compared the achievements to Mozart composing an entire symphony in his head. Hawking was, however, fiercely independent and unwilling to accept help or make concessions for his disabilities. He preferred to be regarded as "a scientist first, popular science writer second, and, in all the ways that matter, a normal human being with the same desires, drives, dreams, and ambitions as the next person." Jane Hawking later noted that "Some people would call it determination, some obstinacy. I've called it both at one time or another." He required much persuasion to accept the use of a wheelchair at the end of the 1960s, but ultimately became notorious for the wildness of his wheelchair driving. Hawking was a popular and witty colleague, but his illness as well as his reputation for brashness and intelligence distanced him from some. In 1969, Hawking accepted a specially created 'Fellowship for Distinction in Science' to remain at Caius.

A daughter, Lucy, was born in 1970. Soon after Hawking discovered what became known as the second law of black hole dynamics, that the event horizon of a black hole can never get smaller. With James M. Bardeen and Brandon Carter, he proposed the four laws of black hole mechanics, drawing an analogy with thermodynamics. To Hawking's irritation, Jacob Bekenstein, a graduate student of John Wheeler, went further—and ultimately correctly—applying thermodynamic concepts literally. In the early 1970s, Hawking's work with Carter, Werner Israel and David C. Robinson strongly supported Wheeler's no-hair theorem that no matter what the original material from which a black hole is created it can be completely described by the properties of mass, electrical charge and rotation. His essay titled "Black Holes" won the Gravity Research Foundation Award in January 1971. Hawking's first book The Large Scale Structure of Space-Time written with George Ellis was published in 1973.

Beginning in 1973, Hawking moved into the study of quantum gravity and quantum mechanics. His work in this area was spurred by a visit to Moscow and discussions with Yakov Borisovich Zel'dovich and Alexei Starobinsky, whose work showed that according to the uncertainty principle rotating black holes emit particles. To Hawking's annoyance, his much-checked calculations produced findings that contradicted his second law, which claimed black holes could never get smaller, and supported Bekenstein's reasoning about their entropy. His results, which Hawking presented from 1974, showed that black holes emit radiation, known today as Hawking radiation, which may continue until they exhaust their energy and evaporate. Initially, Hawking radiation was controversial. However by the late 1970s and following the publication of further research, the discovery was widely accepted as a significant breakthrough in theoretical physics. In March 1974, a few weeks after the announcement of Hawking radiation, Hawking was invested as a Fellow of the Royal Society, one of the youngest scientists to be so honoured.

Hawking rarely discussed his illness and physical challenges, even—in a precedent set during their courtship—with Jane. Hawking's disabilities meant that the responsibilities of home and family rested firmly on his wife's increasingly overwhelmed shoulders, leaving him more time to think about physics. When in 1974 Hawking was appointed to the Sherman Fairchild Distinguished Scholar visiting professorship at the California Institute of Technology (Caltech), Jane proposed that a graduate or post-doctoral student live with them and help with his care. Hawking accepted, and Bernard Carr travelled to California with them as the first of many students who fulfilled this role. The family spent a generally happy and stimulating year in Pasadena. Hawking worked with his friend on the faculty, Kip Thorne, and engaged him in a scientific wager about whether the dark star Cygnus X-1 was a black hole. The wager was a surprising "insurance policy" against the proposition that black holes did not exist. Hawking acknowledged that he had lost the bet in 1990, which was the first of several that he was to make with Thorne and others. Hawking has maintained ties to Caltech, spending a month there almost every year since this first visit.

1975–1990

Hawking returned to Cambridge in 1975 to a new home, a new job—as Reader. Don Page, with whom Hawking had begun a close friendship at Caltech, arrived to work as the live-in graduate student assistant. With Page's help and that of a secretary, Jane's responsibilities were reduced so she could return to her thesis and her new interest in singing. The mid to late 1970s were a period of growing public interest in black holes and of the physicist who was studying them. Hawking was regularly interviewed for print and television. He also received increasing academic recognition of his work. In 1975 he was awarded both the Eddington Medal and the Pius XI Gold Medal, and in 1976 the Dannie Heineman Prize, the Maxwell Prize and the Hughes Medal. Hawking was appointed a professor with a chair in gravitational physics in 1977.  The following year he received the Albert Einstein Medal and an honorary doctorate from the University of Oxford.

Hawking's speech deteriorated, and by the late 1970s he could only be understood by his family and closest friends. To communicate with others, someone who knew him well would translate his speech into intelligible speech. Spurred by a dispute with the university over who would pay for the ramp needed for him to enter his workplace, Hawking and his wife campaigned for improved access and support for those with disabilities in Cambridge, including adapted student housing at the university. In general, however, Hawking had ambivalent feelings about his role as a disability rights champion: while wanting to help others, he sought to detach himself from his illness and its challenges. His lack of engagement led to some criticism. The Hawking family welcomed a third child, Timothy, in April 1979. That autumn Hawking was appointed the Lucasian Professor of Mathematics at the University of Cambridge.

Hawking's inaugural lecture as Lucasian Professor of Mathematics was titled: "Is the end in sight for Theoretical Physics" and proposed N=8 Supergravity as the leading theory to solve many of the outstanding problems physicists were studying.[148] Hawking's promotion coincided with a health crisis which led to Hawking accepting, albeit reluctantly, some nursing services at home. At the same time he was also making a transition in his approach to physics, becoming more intuitive and speculative rather than insisting on mathematical proofs. "I would rather be right than rigorous" he told Kip Thorne. In 1981 he proposed that information in a black hole is irretrievably lost when a black hole evaporates. This information paradox violates the fundamental tenet of quantum mechanics, and was to lead to years of debate, including "the Black Hole War" with Leonard Susskind and Gerard 't Hooft.

In December 1977, Jane had met organist Jonathan Hellyer Jones when singing in a church choir. Hellyer Jones became close to the Hawking family, and by the mid-1980s, he and Jane had developed romantic feelings for each other. According to Jane, her husband was accepting of the situation, stating "he would not object so long as I continued to love him." Jane and Hellyer Jones determined not to break up the family and their relationship remained platonic for a long period.

Cosmological inflation—a theory proposing that following the Big Bang the universe initially expanded incredibly rapidly before settling down to a slower expansion—was proposed by Alan Guth and also developed by Andrei Linde. Following a conference in Moscow in October 1981, Hawking and Gary Gibbons organized a three-week Nuffield Workshop in the summer of 1982 on the Very Early Universe at Cambridge University, which focused mainly on inflation theory. Hawking also began a new line of quantum theory research into the origin of the universe. In 1981 at a Vatican conference he presented work suggesting that there might be no boundary—or beginning or ending—to the universe. He subsequently developed the research in collaboration with Jim Hartle, and in 1983 they published a model, known as the Hartle–Hawking state. It proposed that prior to the Planck epoch, the universe had no boundary in space-time; before the Big Bang, time did not exist and the concept of the beginning of the universe is meaningless. The initial singularity of the classical Big Bang models was replaced with a region akin to the North Pole. One cannot travel north of the North Pole, but there is no boundary there—it is simply the point where all north-running lines meet and end. Initially the no-boundary proposal predicted a closed universe which had implications about the existence of God. As Hawking explained "If the universe has no boundaries but is self-contained... then God would not have had any freedom to choose how the universe began."

Hawking did not rule out the existence of a Creator, asking in A Brief History of Time "Is the unified theory so compelling that it brings about its own existence?" In his early work, Hawking spoke of God in a metaphorical sense. In A Brief History of Time he wrote: "If we discover a complete theory, it would be the ultimate triumph of human reason—for then we should know the mind of God." In the same book he suggested the existence of God was unnecessary to explain the origin of the universe. Later discussions with Neil Turok led to the realisation that it is also compatible with an open universe.

Further work by Hawking in the area of arrows of time led to the 1985 publication of a paper theorising that if the no-boundary proposition were correct, then when the universe stopped expanding and eventually collapsed, time would run backwards. A paper by Don Page and Raymond Laflamme led Hawking to withdraw this concept. Honours continued to be awarded: in 1981 he was awarded the American Franklin Medal, and in 1982 made a Commander of the Order of the British Empire (CBE). Awards do not pay the bills, however, and motivated by the need to finance the children's education and home expenses, in 1982 Hawking determined to write a popular book about the universe that would be accessible to the general public. Instead of publishing with an academic press, he signed a contract with Bantam Books, a mass market publisher, and received a large advance for his book. A first draft of the book, called A Brief History of Time, was completed in 1984.

During a visit to CERN in Geneva in the summer of 1985, Hawking contracted pneumonia which in his condition was life-threatening; he was so ill that Jane was asked if life support should be terminated. She refused but the consequence was a tracheotomy, which would require round-the-clock nursing care, and remove what remained of his speech. The National Health Service would pay for a nursing home but Jane was determined that he would live at home. The cost of the care was funded by an American foundation. Nurses were hired for the three shifts required to provide the round-the-clock support he required. One of those employed was Elaine Mason, who was to become Hawking's second wife. For his communication, Hawking initially raised his eyebrows to choose letters on a spelling card. But he then received a computer program called the "Equalizer" from Walt Woltosz. In a method he uses to this day, using a switch he selects phrases, words or letters from a bank of about 2500–3000 that are scanned. The program was originally run on a desktop computer. However, Elaine Mason's husband David, a computer engineer, adapted a small computer and attached it to his wheelchair. Released from the need to use somebody to interpret his speech, Hawking commented that "I can communicate better now than before I lost my voice." The voice he uses has an American accent and is no longer produced. Despite the availability of other voices, Hawking has retained his original voice, saying that he prefers his current voice and identifies with it. At this point, Hawking activated a switch using his hand and could produce up to 15 words a minute. Lectures were prepared in advance, and sent to the speech synthesiser in short sections as they were delivered.

One of the first messages Hawking produced with his speech generating device was a request for his assistant to help him finish writing A Brief History of Time. Peter Guzzardi, his editor at Bantam, pushed him to explain his ideas clearly in non-technical language, a process that required multiple revisions from an increasingly irritated Hawking. The book was published in April 1988 in the US and in June in the UK, and proved to be an extraordinary success, rising quickly to the top of bestseller lists in both countries and remaining there for weeks and months. The book was translated into multiple languages, and ultimately sold an estimated 9 million copies. Media attention was intense, and Newsweek magazine cover and a television special both described him as "Master of the Universe". Success led to significant financial rewards, but also the challenges of celebrity status. Hawking travelled extensively to promote his work, and enjoyed partying and dancing into the small hours. He had difficulty refusing the invitations and visitors which left limited time for work and his students. Some colleagues were resentful of the attention Hawking received, feeling it was due to his disability. He received further academic recognition, including five further honorary degrees, the Gold Medal of the Royal Astronomical Society (1985), the Paul Dirac Medal (1987) and, jointly with Penrose, the prestigious Wolf Prize (1988). In 1989, he was named a Companion of Honour by Queen Elizabeth II.

1990–2000

Hawking's marriage had been strained for many years. Jane felt overwhelmed by the intrusion into their family life of the required nurses and assistants. The impact of his celebrity was challenging for colleagues and family members, and in one interview Jane described her role as "simply to tell him that he's not God." Hawking's agnostic views of religion also contrasted with her strong Christian faith, and resulted in tension. In the late 1980s Hawking had grown close to one of his nurses, Elaine Mason, to the dismay of some colleagues, caregivers and family members who were disturbed by her strength of personality and protectiveness. Hawking told Jane that he was leaving her for Mason, and departed the family home in February 1990. Following his divorce from Jane in the spring of 1995, Hawking married Mason in September, declaring "It's wonderful—I have married the woman I love."

Hawking pursued his work in physics: in 1993 he co-edited a book on Euclidean quantum gravity with Gary Gibbons, and published a collected edition of his own articles on black holes and the Big Bang. In 1994 at Cambridge's Newton Institute, Hawking and Penrose delivered a series of six lectures, which were published in 1996 as "The Nature of Space and Time". In 1997 he conceded a 1991 public scientific wager made with Kip Thorne and John Preskill of Caltech. Hawking had bet that Penrose's proposal of a "cosmic censorship conjecture"—that there could be no "naked singularities" unclothed within a horizon—was correct. After discovering his concession might have been premature, a new, more refined, wager was made. This specified that such singularities would occur without extra conditions. The same year, Thorne, Hawking and Preskill made another bet, this time concerning the black hole information paradox. Thorne and Hawking argued that since general relativity made it impossible for black holes to radiate and lose information, the mass-energy and information carried by Hawking Radiation must be "new", and not from inside the black hole event horizon. Since this contradicted the quantum mechanics of microcausality, quantum mechanics theory would need to be rewritten. Preskill argued the opposite, that since quantum mechanics suggests that the information emitted by a black hole relates to information that fell in at an earlier time, the concept of black holes given by general relativity must be modified in some way.

Hawking also maintained his public profile, including bringing science to a wider audience. In 1992 a film version of "A Brief History of Time"—directed by Errol Morris and produced by Steven Spielberg—was premiered. Hawking had wanted the film to be scientific rather than biographical, but was persuaded otherwise. The film, while a critical success, was however not widely released. A popular-level collection of essays, interviews and talk titled Black Holes and Baby Universes and Other Essays was published in 1993 and six-part television series Stephen Hawking's Universe and companion book appeared in 1997. As Hawking insisted, this time the focus was entirely on science. He also made several appearances in popular media. At the release party for the home video version of the "A Brief History of Time", Leonard Nimoy, who had played Spock on Star Trek, learnt that Hawking was interested in appearing on the show. Nimoy made the necessary contact and Hawking appeared as himself on Star Trek: The Next Generation in 1993. The same year, his synthesiser voice was recorded for the Pink Floyd song "Keep Talking", and in 1999 for an appearance on The Simpsons.

In the 1990s, Hawking accepted more openly the mantle of role model for disabled people, including lecturing on the subject and participating in fundraising activities. At the turn of the century, he and eleven other luminaries signed the "Charter for the Third Millennium on Disability" which called on governments to prevent disability and protect disabled rights. In 1999 Hawking was awarded the Julius Edgar Lilienfeld Prize of the American Physical Society. The same year, Jane Hawking published a memoir, Music to Move the Stars, describing her marriage to Hawking and its breakdown. Its revelations caused a sensation in the media, but as was his usual practice regarding his personal life, Hawking made no public comment except to say that he did not read biographies about himself.

Antonie van Leeuwenhoek

About Antonie van Leeuwenhoek

Antonie Philips van Leeuwenhoek[note 1] (October 24, 1632 – August 26, 1723) was a Dutch tradesman and scientist. He is commonly known as "the Father of Microbiology", and considered to be the first microbiologist. He is best known for his work on the improvement of the microscope and for his contributions towards the establishment of microbiology.

Raised in Delft, Netherlands, Leeuwenhoek worked as a draper in his youth, and founded his own shop in 1654. He made a name for himself in municipal politics, and eventually developed an interest in lensmaking. Using his handcrafted microscopes, he was the first to observe and describe single-celled organisms, which he originally referred to as animalcules, and which are now referred to as microorganisms. He was also the first to record microscopic observations of muscle fibers, bacteria, spermatozoa, and blood flow in capillaries (small blood vessels). Leeuwenhoek did not author any books; his discoveries came to light through correspondence with the Royal Society, which published his letters.

Early life and career

Antonie van Leeuwenhoek was born in Delft, Holland, on October 24, 1632. Christened Thonis, he is believed to be of Dutch ancestry: his father, Philips Antonysz van Leeuwenhoek, was a basket maker who died when Antony was five years old. His mother, Margaretha (Bel van den Berch), came from a well-to-do brewer's family, and married Jacbon Jansz Molijn, a painter, after Philips' death. Antony had four older sisters, Margriete, Geertruyt, Neeltge, and Catharina. Little is known of his early life; he attended school near Leyden for a short time before being sent to live in Benthuizen with his uncle, an attorney and town clerk. He became an apprentice at a linen-draper's shop in Amsterdam at the age of 16.

He married Barbara de Mey in July 1654, with whom he would have one surviving daughter, Maria (four other children died in infancy). That year he returned to Delft, where he would live and study for the rest of his life. He opened a draper's shop, which he ran throughout the 1650s. Barbara died in 1666, and in 1671 Leeuwenhoek married Cornelia Swalmius, with whom he had no surviving children. His status in Delft grew throughout the following years, although he would remain an obscure figure outside of the city. He received a lucrative municipal title as chamberlain for the Delft sheriffs' assembly chamber in 1660, a position which he would hold for almost 40 years. In 1669 he was named a surveyor by the Court of Holland; later he would become a municipal "wine-gauger" in charge of the city's wine imports.

Leeuwenhoek was a contemporary of another famous Delft citizen, painter Johannes Vermeer, who was baptized just four days earlier. It has been suggested that he is the man portrayed in two of Vermeer's paintings of the late 1660s, The Astronomer and The Geographer. However, others argue that there appears to be little physical similarity. Because they were both relatively important men in a city with only 24,000 inhabitants, it is likely that they were at least acquaintances. Also, it is known that Leeuwenhoek acted as the executor of the will when the painter died in 1675.

Antoine Lavoisier

About Antoine Lavoisier

Antoine-Laurent de Lavoisier (26 August 1743 – 8 May 1794) was a French nobleman and chemist central to the 18th-century Chemical Revolution and a large influence on both the histories of chemistry and biology. He is widely considered to be the "Father of Modern Chemistry."

It is generally accepted that Lavoisier's great accomplishments in chemistry largely stem from the fact that he changed the science from a qualitative to a quantitative one. Lavoisier is most noted for his discovery of the role oxygen plays in combustion. He recognized and named oxygen (1778) and hydrogen (1783) and opposed the phlogiston theory. Lavoisier helped construct the metric system, wrote the first extensive list of elements, and helped to reform chemical nomenclature. He predicted the existence of silicon (1787) and was also the first to establish that sulfur was an element (1777) rather than a compound. He discovered that, although matter may change its form or shape, its mass always remains the same.

Lavoisier was an administrator of the Ferme Générale and a powerful member of a number of other aristocratic councils. All of these political and economic activities enabled him to fund his scientific research. At the height of the French Revolution, he was accused by Jean-Paul Marat of selling adulterated tobacco and of other crimes, and was eventually guillotined a year after Marat's death.

Biography

Antoine-Laurent Lavoisier was born to a wealthy family in Paris on 26 August 1743. The son of an attorney at the Parlement of Paris, he inherited a large fortune at the age of five with the passing of his mother. Lavoisier began his schooling at the Collège des Quatre-Nations (known as the Collège Mazarin) in Paris in 1754 at the age of 11. In his last two years (1760–1761) at the college his scientific interests were aroused, and he studied chemistry, botany, astronomy, and mathematics. In the philosophy class he came under the tutelage of Abbé Nicolas Louis de Lacaille, a distinguished mathematician and observational astronomer who imbued the young Lavoisier with an interest in meteorological observation, an enthusiasm which never left him. Lavoisier entered the school of law, where he received a bachelor's degree in 1763 and a licentiate in 1764. Lavoisier received a law degree and was admitted to the bar, but never practiced as a lawyer. However, he continued his scientific education in his spare time.

Early scientific work

Lavoisier's education was filled with the ideals of the French Enlightenment of the time, and he was fascinated by Pierre Macquer's dictionary of chemistry. He attended lectures in the natural sciences. Lavoisier's devotion and passion for chemistry were largely influenced by Étienne Condillac, a prominent French scholar of the 18th century. His first chemical publication appeared in 1764. From 1763 to 1767, he studied geology under Jean-Étienne Guettard. In collaboration with Guettard, Lavoisier worked on a geological survey of Alsace-Lorraine in June 1767. In 1764 he read his first paper to the French Academy of Sciences, France's most elite scientific society, on the chemical and physical properties of gypsum (hydrated calcium sulfate), and in 1766 he was awarded a gold medal by the King for an essay on the problems of urban street lighting. In 1768 Lavoisier received a provisional appointment to the Academy of Sciences. In 1769, he worked on the first geological map of France.

Andreas Vesalius

About Andreas Vesalius

Andreas Vesalius (31 December 1514 – 15 October 1564) was a Brabantian (in modern-day Belgium) anatomist, physician, and author of one of the most influential books on human anatomy, De humani corporis fabrica (On the Fabric of the Human Body). Vesalius is often referred to as the founder of modern human anatomy. He was professor at the University of Padua and later became Imperial physician at the court of Emperor Charles V.

Andreas Vesalius is the Latinized form of the Dutch Andries van Wezel, a common practice among European scholars in his time. His name is also given as Andrea Vesalius, Andrea Vesalio, Andreas Vesal, André Vesalio and Andre Vesalepo.

Medical career

The day of his graduation he was immediately offered the chair of Surgery and Anatomy (explicator chirurgiae) at Padua. He also guest lectured at Bologna and Pisa. Previously these topics had been taught primarily from reading classical texts, mainly Galen, followed by an animal dissection by a barber-surgeon whose work was directed by the lecturer. No attempt was made to actually check Galen's claims; these were considered unassailable. Vesalius, on the other hand, carried out dissection as the primary teaching tool, handling the actual work himself and urging students to perform dissection themselves. Hands-on direct observation was considered the only reliable resource, a huge break with medieval practice.

He created detailed illustrations of anatomy for students in the form of six large woodcut anatomical posters. When he found that some of these were being widely copied, he published them all in 1538 under the title Tabulae anatomicae sex. He followed this in 1539 with an updated version of Guinter's anatomical handbook, Institutiones anatomicae.

In 1539 he also published his Venesection letter, on bloodletting. This was a popular treatment for almost any illness, but there was some debate about where to take the blood from. The classical Greek procedure, advocated by Galen, was to let blood from a site near the location of the illness. However, the Muslim and medieval practice was to draw a smaller amount blood from a distant location. Vesalius' pamphlet generally supported Galen's view, but with qualifications that rejected the infallibility of Galen.

In 1541, while in Bologna, Vesalius uncovered the fact that all of Galen's research had been based upon animal anatomy rather than the human; since dissection had been banned in ancient Rome, Galen had dissected Barbary apes instead, and argued that they would be anatomically similar to humans. He also contributed to the new Giunta edition of Galen's collected works and began writing his own anatomical text. Until Vesalius pointed out Galen's substitution of animal for human anatomy, it had gone unnoticed and had long been the basis of studying human anatomy. However, some people still chose to follow Galen and resented Vesalius for calling attention to such glaring mistakes.

Galen assumed arteries carried the purest blood to higher organs such as the brain and lungs from the left ventricle of the heart, while veins carried blood to the lesser organs such as the stomach from the right ventricle. In order that this theory could be correct some sort of holes were needed to interconnect the ventricles, and so in the spirit of Galen's time, he claimed to have found them, adjusting the facts to suit his theory. So paramount was the authority of Galen that for 1400 years a succession of anatomists had claimed to find these holes until finally Vesalius admitted he could not find them. However, while Vesalius dared to admit he could not find these holes, he did not dream of disputing Galen on the distribution of blood, and so imagined it distilled through the unbroken partition between the ventricles.

Other famous examples of Vesalius disproving Galen in particular was his discovery that the lower jaw was only one bone, not two (which Galen had assumed from animal dissection) and his proof that humans do not have the "miraculous network" of blood vessels at the base of the brain which is found in sheep and other ungulates.

In 1543, Vesalius conducted a public dissection of the body of Jakob Karrer von Gebweiler, a notorious felon from the city of Basel, Switzerland. He assembled the bones and finally donated the skeleton to the University of Basel. This preparation ("The Basel Skeleton") is Vesalius' only well-preserved skeletal preparation today, and is also the world's oldest surviving anatomical preparation. It is still displayed at the Anatomical Museum of the University of Basel.

In the same year Vesalius took residence in Basel to help Johannes Oporinus publish the seven-volume De humani corporis fabrica (On the fabric of the human body), a groundbreaking work of human anatomy which he dedicated to Charles V. Many believe it was illustrated by Titian's pupil Jan Stephen van Calcar, but evidence is lacking, and it is unlikely a single artist created all 273 illustrations in so short a time. About the same time he published an abridged edition for students, Andrea Vesalii suorum de humani corporis fabrica librorum epitome, and dedicated it to Philip II of Spain, son of the Emperor.

Though Vesalius' work was not the first such work based on actual autopsy, nor even the first work of this era, the production values, highly detailed and intricate plates, and the likelihood that the artists who produced it were clearly present at the dissections themselves made it into an instant classic. Pirated editions were available almost immediately, a fact Vesalius acknowledged would happen in a printer's note. Vesalius was 28 years old when the first edition of Fabrica was published.

Imperial physician and death

Soon after publication, Vesalius was invited as Imperial physician to the court of Emperor Charles V. He informed the Venetian Senate that he was leaving his post in Padua, which prompted Duoooke Cosimo I de' Medici to invite him to move to the expanding university in Pisa, which he turned down. Vesalius took up a position in the court, where he had to deal with the other physicians mocking him as being a barber.

Over the next eleven years Vesalius traveled with the court, treating injuries from battle or tournaments, performing postmortems, administering medications, and writing private letters addressing specific medical questions. During these years he also wrote the Epistle on the China root, a short text on the properties of a medical plant whose efficacy he doubted, as well as defense of his anatomical findings. This elicited a new round of attacks on his work that called for him to be punished by the emperor. In 1551, Charles V commissioned an inquiry in Salamanca to investigate the religious implications of his methods. Vesalius' work was cleared by the board, but the attacks continued. Four years later one of his main detractors and one-time professors Jacobus Sylvius, published an article that claimed that the human body itself had changed since Galen had studied it.

After the abdication of Emperor Charles V he continued at court in great favor with his son Philip II, who rewarded him with a pension for life by making him a count palatine. In 1555 he published a revised edition of De humani corporis fabrica.

In 1564 Vesalius went on a pilgrimage to the Holy Land. He sailed with the Venetian fleet under James Malatesta via Cyprus. When he reached Jerusalem, he received a message from the Venetian senate requesting him again to accept the Paduan professorship, which had become vacant by the death of his friend and pupil Fallopius.

After struggling for many days with the adverse winds in the Ionian Sea, he was wrecked on the island of Zakynthos. Here he soon died in such debt that a benefactor kindly paid for his funeral. At the time of his death he was scarcely fifty years of age. He was buried somewhere in the island of Korfu.

For many years it was assumed that Vesalius's pilgrimage was due to pressures of the Inquisition. Today this is generally considered to be without foundation (see C.D. O'Malley Andreas Vesalius' Pilgrimage, Isis 45:2, 1954) and is dismissed by modern biographers. It appears the story was spread by Hubert Languet, a diplomat under Emperor Charles V and then under the Prince of Orange, who claimed in 1565 that Vesalius had performed an autopsy on an aristocrat in Spain when the heart was still beating, leading to the Inquisition condemning him to death. The story went on to claim that Philip II had the sentence commuted to a pilgrimage. The story re-surfaced several times over the next few years, living on until recent times.

Andre Marie Ampere

About Andre Marie Ampere

Andre Marie Ampere (20 January 1775 – 10 June 1836) was a French physicist and mathematician who is generally regarded as one of the main founders of the science of classical electromagnetism, which he referred to as "electrodynamics". The SI unit of measurement of electric current, the ampere, is named after him.

Biography

Andre-Marie Ampère was born on 20 January 1775 to Jean-Jacques Ampère, a prosperous businessman, and Jeanne Antoinette Desutières-Sarcey Ampère during the height of the French Enlightenment. He spent his childhood and adolescence at the family property at Poleymieux-au-Mont-d'Or near Lyon. Jean-Jacques Ampère, a successful merchant, was an admirer of the philosophy of Jean-Jacques Rousseau, whose theories of education (as outlined in his treatise Émile) were the basis of Ampère’s education. Rousseau believed that young boys should avoid formal schooling and pursue instead an “education direct from nature.” Ampère’s father actualized this ideal by allowing his son to educate himself within the walls of his well-stocked library. French Enlightenment masterpieces such as Georges-Louis Leclerc, comte de Buffon’s Histoire naturelle, générale et particulière (begun in 1749) and Denis Diderot and Jean le Rond d'Alembert’s Encyclopédie (volumes added between 1751 and 1772) thus became Ampère’s schoolmasters. The young Ampère, however, soon resumed his Latin lessons, which enabled him to master the works of Leonhard Euler and Daniel Bernoulli.

French Revolution

In addition, Ampère used his access to the latest mathematical books to begin teaching himself advanced mathematics at age 12. In later life Ampère claimed that he knew as much about mathematics and science when he was eighteen as ever he knew; but, a polymath, his reading embraced history, travels, poetry, philosophy, and the natural sciences. His mother was a devout woman, so Ampère was also initiated into the Catholic faith along with Enlightenment science. The French Revolution (1789–99) that began during his youth was also influential: Ampère’s father was called into public service by the new revolutionary government, becoming a justice of the peace in a small town near Lyon. When the Jacobin faction seized control of the Revolutionary government in 1792, his father Jean-Jacques Ampère resisted the new political tides, and he was guillotined on 24 November 1793, as part of the Jacobin purges of the period.

In 1796 Ampère met Julie Carron, and in 1799 they were married. André-Marie Ampère took his first regular job in 1799 as a mathematics teacher, which gave him the financial security to marry Carron and father his first child, Jean-Jacques (named after his father), the next year. (Jean-Jacques Ampère eventually achieved his own fame as a scholar of languages.) Ampère’s maturation corresponded with the transition to the Napoleonic regime in France, and the young father and teacher found new opportunities for success within the technocratic structures favoured by the new French First Counsel. In 1802 Ampère was appointed a professor of physics and chemistry at the École Centrale in Bourg-en-Bresse, leaving his ailing wife and infant son in Lyon. He used his time in Bourg to research mathematics, producing Considérations sur la théorie mathématique de jeu (1802; “Considerations on the Mathematical Theory of Games”), a treatise on mathematical probability that he sent to the Paris Academy of Sciences in 1803!

Teaching career

After the death of his wife in July 1803, Ampère moved to Paris, where he began a tutoring post at the new École Polytechnique in 1804. Despite his lack of formal qualifications, Ampère was appointed a professor of mathematics at the school in 1809. As well as holding positions at this school until 1828, in 1819 and 1820 Ampère offered courses in philosophy and astronomy, respectively, at the University of Paris, and in 1824 he was elected to the prestigious chair in experimental physics at the Collège de France. In 1814 Ampère was invited to join the class of mathematicians in the new Institute Impériale, the umbrella under which the reformed state Academy of Sciences would sit.RS

Ampère engaged in a diverse array of scientific inquiries during the years leading up to his election to the academy—writing papers and engaging in topics from mathematics and philosophy to chemistry and astronomy. Such breadth was customary among the leading scientific intellectuals of the day. Ampère claimed that "at eighteen years he found three culminating points in his life, his First Communion, the reading of Antoine Leonard Thomas's "Eulogy of Descartes", and the Taking of the Bastille. On the day of his wife's death he wrote two verses from the Psalms, and the prayer, 'O Lord, God of Mercy, unite me in Heaven with those whom you have permitted me to love on earth.' Serious doubts harassed him at times, and made him very unhappy. Then he would take refuge in the reading of the Bible and the Fathers of the Church."

For a time he took into his family the young student Antoine-Frédéric Ozanam (1813–1853), one of the founders of the Conference of Charity, later known as the Society of Saint Vincent de Paul. Through Ampère, Ozanam had contact with leaders of the neo-Catholic movement, such as François-René de Chateaubriand, Jean-Baptiste Henri Lacordaire, and Charles Forbes René de Montalembert. Ozanam was beatified by Pope John Paul II in 1998.

Work in electromagnetism

In September 1820, Ampère’s friend and eventual eulogist François Arago showed the members of the French Academy of Sciences the surprising discovery of Danish physicist Hans Christian Ørsted that a magnetic needle is deflected by an adjacent electric current. Ampère began developing a mathematical and physical theory to understand the relationship between electricity and magnetism. Furthering Ørsted’s experimental work, Ampère showed that two parallel wires carrying electric currents attract or repel each other, depending on whether the currents flow in the same or opposite directions, respectively - this laid the foundation of electrodynamics. He also applied mathematics in generalizing physical laws from these experimental results. The most important of these was the principle that came to be called Ampère’s law, which states that the mutual action of two lengths of current-carrying wire is proportional to their lengths and to the intensities of their currents. Ampère also applied this same principle to magnetism, showing the harmony between his law and French physicist Charles Augustin de Coulomb’s law of magnetic action. Ampère’s devotion to, and skill with, experimental techniques anchored his science within the emerging fields of experimental physics.

Ampère also provided a physical understanding of the electromagnetic relationship, theorizing the existence of an “electrodynamic molecule” (the forerunner of the idea of the electron) that served as the component element of both electricity and magnetism. Using this physical explanation of electromagnetic motion, Ampère developed a physical account of electromagnetic phenomena that was both empirically demonstrable and mathematically predictive. In 1827 Ampère published his magnum opus, Mémoire sur la théorie mathématique des phénomènes électrodynamiques uniquement déduite de l’experience (Memoir on the Mathematical Theory of Electrodynamic Phenomena, Uniquely Deduced from Experience), the work that coined the name of his new science, electrodynamics, and became known ever after as its founding treatise.

In 1827 Ampère was elected a Foreign Member of the Royal Society and in 1828, a foreign member of the Royal Swedish Academy of Science. In recognition of his contribution to the creation of modern electrical science, an international convention signed in 1881 established the ampere as a standard unit of electrical measurement, along with the coulomb, volt, ohm, and watt, which are named, respectively, after Ampère’s contemporaries Charles-Augustin de Coulomb of France, Alessandro Volta of Italy, Georg Ohm of Germany, and James Watt of Scotland. His name is one of the 72 names inscribed on the Eiffel Tower.

Anders Celsius

About Anders Celsius

Anders Celsius (27 November 1701 – 25 April 1744) was a Swedish astronomer, physicist and mathematician. He was professor of astronomy at Uppsala University from 1730 to 1744, but traveled from 1732 to 1735 visiting notable observatories in Germany, Italy and France. He founded the Uppsala Astronomical Observatory in 1741, and in 1742 proposed the Celsius temperature scale which bears his name.

Early life and education

Anders Celsius was born in Uppsala, Sweden on 27 November 1701. His family originated from Ovanåker in the province of Hälsingland. Their family estate was at Doma, also known as Höjen or Högen (locally as Högen 2). The name Celsius is a latinization of the estate's name (Latin celsus "mound").

As the son of an astronomy professor, Nils Celsius, and the grandson of the mathematician Magnus Celsius and the astronomer Anders Spole, Celsius chose a career in science. He was a talented mathematician from an early age. Anders Celsius studied at Uppsala University, where his father was a teacher, and in 1730 he too, became a professor of astronomy there.

Career

In 1730, Celsius published the Nova Methodus distantiam solis a terra determinandi (New Method for Determining the Distance from the Earth to the Sun). His research also involved the study of auroral phenomena, which he conducted with his assistant Olof Hiorter, and he was the first to suggest a connection between the aurora borealis and changes in the magnetic field of the Earth. He observed the variations of a compass needle and found that larger deflections correlated with stronger auroral activity. At Nuremberg in 1733, he published a collection of 316 observations of the aurora borealis made by himself and others over the period 1716–1732.

Celsius traveled frequently in the early 1730s, including to Germany, Italy and France, when he visited most of the major European observatories. In Paris he advocated the measurement of an arc of the meridian in Lapland. In 1736, he participated in the expedition organized for that purpose by the French Academy of Sciences, led by the French mathematician Pierre Louis Maupertuis (1698–1759) to measure a degree of latitude. The aim of the expedition was to measure the length of a degree along a meridian, close to the pole, and compare the result with a similar expedition to Peru, today in Ecuador, near the equator. The expeditions confirmed Isaac Newton's belief that the shape of the earth is an ellipsoid flattened at the poles.

In 1738, he published the De observationibus pro figura telluris determinanda (Observations on Determining the Shape of the Earth). Celsius' participation in the Lapland expedition won him much respect in Sweden with the government and his peers, and played a key role in generating interest from the Swedish authorities in donating the resources required to construct a new modern observatory in Uppsala. He was successful in the request, and Celsius founded the Uppsala Astronomical Observatory in 1741. The observatory was equipped with instruments purchased during his long voyage abroad, comprising the most modern instrumental technology of the period.

In astronomy, Celsius began a series of observations using colored glass plates to record the magnitude (a measure of brightness) of certain stars. This was the first attempt to measure the intensity of starlight with a tool other than the human eye. He made observations of eclipses and various astronomical objects and published catalogues of carefully determined magnitudes for some 300 stars using his own photometric system (mean error=0.4 mag).

Celsius was the first to perform and publish careful experiments aiming at the definition of an international temperature scale on scientific grounds. In his Swedish paper "Observations of two persistent degrees on a thermometer" he reports on experiments to check that the freezing point is independent of latitude (and of atmospheric pressure). He determined the dependence of the boiling of water with atmospheric pressure which was accurate even by modern day standards. He further gave a rule for the determination of the boiling point if the barometric pressure deviates from a certain standard pressure. He proposed the Celsius temperature scale in a paper to the Royal Society of Sciences in Uppsala, the oldest Swedish scientific society, founded in 1710. His thermometer was calibrated with a value of 100° for the freezing point of water and 0° for the boiling point. In 1745, a year after Celsius' death, the scale was reversed by Carl Linnaeus to facilitate more practical measurement. Celsius originally called his scale centigrade derived from the Latin for "hundred steps". For years it was simply referred to as the Swedish thermometer.

Celsius conducted many geographical measurements for the Swedish General map, and was one of earliest to note that much of Scandinavia is slowly rising above sea level, a continuous process which has been occurring since the melting of the ice from the latest ice age. However, he wrongly posed the notion that the water was evaporating.

In 1725 he became secretary of the Royal Society of Sciences in Uppsala, and served at this post until his death from tuberculosis in 1744. He supported the formation of the Royal Swedish Academy of Sciences in Stockholm in 1739 by Linnaeus and five others, and was elected a member at the first meeting of this academy. It was in fact Celsius who proposed the new academy's name.

Amedeo Avogadro

About Amedeo Avogadro

Lorenzo Romano Amedeo Carlo Avogadro di Quaregna e di Cerreto, Count of Quaregna and Cerreto (9 August 1776, Turin, Piedmont – 9 July 1856) was an Italian scientist. He is most noted for his contributions to molecular theory, including what is known as Avogadro's law. In tribute to him, the number of elementary entities (atoms, molecules, ions or other particles) in 1 mole of a substance, 6.02214179(30)×1023, is known as the Avogadro constant.

Biography

Amedeo Carlo Avogadro was born in Turin, Italy in 1776 to a noble family of Piedmont, Italy.

He graduated in ecclesiastical law at the early age of 31 and began to practice. Soon after, he dedicated himself to physics and mathematics (then called positive philosophy), and in 1809 started teaching them at a liceo (high school) in Vercelli, where his family lived and had some property.

In 1810, he published an article with the title Essai d'une manière de déterminer les masses relatives des molécules élémentaires des corps, et les proportions selon lesquelles elles entrent dans ces combinaisons ("Essay on Determining the Relative Masses of the Elementary Molecules of Bodies and the Proportions by Which They Enter These Combinations"), which contains Avogadro's hypothesis. Avogadro submitted this essay to a French journal, Jean-Claude Delamétherie's Journal de Physique, de Chimie et d'Histoire naturelle (Journal of Physics, Chemistry and Natural History) so it was written in French, not Italian. (Note: France effectively controlled northern Italy from 1796 to 1814.)

In 1820, he became professor of physics at the University of Turin. After the downfall of the French Emperor Napoléon in 1815, Piedmont again came under the control of the King of Piedmont-Sardinia, ruling from Turin.

Avogadro was active in the revolutionary movements of 1821 against King Victor Emmanuel I. As a result, he lost his chair in 1823 (or, as the university officially declared, it was "very glad to allow this interesting scientist to take a rest from heavy teaching duties, in order to be able to give better attention to his researches").

Eventually, King Charles Albert granted a Constitution (Statuto Albertino) in 1848. Well before this, Avogadro had been recalled to the university in Turin in 1833, where he taught for another twenty years.

Little is known about Avogadro's private life, which appears to have been sober and religious. He married Felicita Mazzé and had six children.

Some historians[which?] suggest that he sponsored some Sardinian revolutionaries, who were stopped by the announcement of Charles Albert's constitution.

Avogadro held posts dealing with statistics, meteorology, and weights and measures (he introduced the metric system into Piedmont) and was a member of the Royal Superior Council on Public Instruction.

In honor of Avogadro's contributions to molecular theory, the number of molecules in one mole was named Avogadro's number, NA or "Avogadro's constant". It is approximately 6.0221415 × 1023. Avogadro's number is used to compute the results of chemical reactions. It allows chemists to determine amounts of substances produced in a given reaction to a great degree of accuracy.

Johann Josef Loschmidt first calculated the value of Avogadro's number, often referred to as the Loschmidt number in German-speaking countries (Loschmidt constant now has another meaning).

Alfred Wegener

About Alfred Wegener

Alfred Lothar Wegener (November 1, 1880 – November 1930) was a German polar researcher, geophysicist and meteorologist.

During his lifetime he was primarily known for his achievements in meteorology and as a pioneer of polar research, but today he is most remembered for advancing the theory of continental drift (Kontinentalverschiebung) in 1912, which hypothesized that the continents were slowly drifting around the Earth. His hypothesis was controversial and not widely accepted until the 1950s, when numerous discoveries such as palaeomagnetism provided strong support for continental drift, and thereby a substantial basis for today's model of Plate tectonics. Wegener was involved in several expeditions to Greenland to study polar air circulation before the existence of the jet stream was accepted. Expedition participants made many meteorological observations and achieved the first-ever overwintering on the inland Greenland ice sheet as well as the first-ever boring of ice cores on a moving Arctic glacier.

Biography

On November 1, 1880, Alfred Wegener was born in Berlin as the youngest of five children in a clergyman's family. His father, Richard Wegener, was a theologian and teacher of classical languages at the Berlinisches Gymnasium zum Grauen Kloster. In 1886 his family purchased a former manor house near Rheinsberg, which they used as a vacation home. Today there is an Alfred Wegener Memorial site and tourist information office in a nearby building that was once the local schoolhouse.

Wegener attended school at the Köllnische Gymnasium on Wallstrasse in Berlin (a fact which is memorialized on a plaque on this protected building, now a school of music), graduating as the best in his class. Afterward he studied Physics, meteorology and Astronomy in Berlin, Heidelberg and Innsbruck. From 1902 to 1903 during his studies he was an assistant at the Urania astronomical observatory. He obtained a doctorate in astronomy in 1905 based on a dissertation written under the supervision of Julius Bauschinger at Friedrich Wilhelms University (today Humboldt University), Berlin. Wegener had always maintained a strong interest in the developing fields of meteorology and climatology and his studies afterwards focused on these disciplines.

In 1905 Wegener became an assistant at the Aeronautischen Observatorium Lindenberg near Beeskow. He worked there with his brother Kurt, two years his senior, who was likewise a scientist with an interest in meteorology and polar research. The two pioneered the use of weather balloons to track air masses. On a balloon ascent undertaken to carry out meteorological investigations and to test a celestial navigation method using a particular type of quadrant (“Libellenquadrant”), the Wegener brothers set a new record for a continuous balloon flight, remaining aloft 52.5 hours from April 5–7, 1906.

In that same year 1906, Wegener participated in the first of his four Greenland expeditions, later regarding this experience as marking a decisive turning point in his life. The expedition was led by the Dane Ludvig Mylius-Erichsen and charged with studying the last unknown portion of the northeastern coast of Greenland. During the expedition Wegener constructed the first meteorological station in Greenland near Danmarkshavn, where he launched kites and tethered balloons to make meteorological measurements in an Arctic climatic zone. Here Wegener also made his first acquaintance with death in a wilderness of ice when the expedition leader and two of his colleagues died on an exploratory trip undertaken with sled dogs.

After his return in 1908 and until World War I, Wegener was a lecturer in meteorology, applied astronomy and cosmic physics at the University of Marburg. His students and colleagues in Marburg particularly valued his ability to clearly and understandably explain even complex topics and current research findings without sacrificing precision. His lectures formed the basis of what was to become a standard textbook in meteorology, first written In 1909/1910: Thermodynamik der Atmosphäre (Thermodynamics of the Atmosphere), in which he incorporated many of the results of the Greenland expedition.

On 6 January 1912 he publicized his first thoughts about continental drift in a lecture at a session of the Geologischen Vereinigung at the Senckenberg-Museum, Frankfurt am Main and in three articles in the journal Petermanns Geographischen Mitteilungen.

Thomas Alva Edison

About Thomas Alva Edison

Thomas Alva Edison (February 11, 1847 – October 18, 1931) was an American inventor and businessman. He developed many devices that greatly influenced life around the world, including the phonograph, the motion picture camera, and a long-lasting, practical electric light bulb. Dubbed "The Wizard of Menlo Park", he was one of the first inventors to apply the principles of mass production and large-scale teamwork to the process of invention, and because of that, he is often credited with the creation of the first industrial research laboratory.

Edison was a prolific inventor, holding 1,093 US patents in his name, as well as many patents in the United Kingdom, France, and Germany. More significant than the number of Edison's patents, are the impacts of his inventions, because Edison not only invented things, his inventions established major new industries world-wide, notably, electric light and power utilities, sound recording and motion pictures. Edison's inventions contributed to mass communication and, in particular, telecommunications. These included a stock ticker, a mechanical vote recorder, a battery for an electric car, electrical power, recorded music and motion pictures.

His advanced work in these fields was an outgrowth of his early career as a telegraph operator. Edison developed a system of electric-power generation and distribution to homes, businesses, and factories – a crucial development in the modern industrialized world. His first power station was on Pearl Street in Manhattan, New York.

Early life

Thomas Edison was born in Milan, Ohio, and grew up in Port Huron, Michigan. He was the seventh and last child of Samuel Ogden Edison, Jr. (1804–96, born in Marshalltown, Nova Scotia, Canada) and Nancy Matthews Elliott (1810–1871, born in Chenango County, New York). His father had to escape from Canada because he took part in the unsuccessful Mackenzie Rebellion of 1837. Edison reported being of Dutch ancestry.

In school, the young Edison's mind often wandered, and his teacher, the Reverend Engle, was overheard calling him "addled". This ended Edison's three months of official schooling. Edison recalled later, "My mother was the making of me. She was so true, so sure of me; and I felt I had something to live for, someone I must not disappoint." His mother taught him at home. Much of his education came from reading R.G. Parker's School of Natural Philosophy and The Cooper Union.

Edison developed hearing problems at an early age. The cause of his deafness has been attributed to a bout of scarlet fever during childhood and recurring untreated middle-ear infections. Around the middle of his career, Edison attributed the hearing impairment to being struck on the ears by a train conductor when his chemical laboratory in a boxcar caught fire and he was thrown off the train in Smiths Creek, Michigan, along with his apparatus and chemicals. In his later years, he modified the story to say the injury occurred when the conductor, in helping him onto a moving train, lifted him by the ears.

Edison's family moved to Port Huron, Michigan, after the railroad bypassed Milan in 1854 and business declined; his life there was bittersweet. Edison sold candy and newspapers on trains running from Port Huron to Detroit, and sold vegetables to supplement his income. He also studied qualitative analysis, and conducted chemical experiments on the train until an accident prohibited further work of the kind.

Edison obtained the exclusive right to sell newspapers on the road, and, with the aid of four assistants, he set in type and printed the Grand Trunk Herald, which he sold with his other papers. This began Edison's long streak of entrepreneurial ventures, as he discovered his talents as a businessman. These talents eventually led him to found 14 companies, including General Electric, which is still one of the largest publicly traded companies in the world.

Telegrapher

Edison became a telegraph operator after he saved three-year-old Jimmie MacKenzie from being struck by a runaway train. Jimmie's father, station agent J.U. MacKenzie of Mount Clemens, Michigan, was so grateful that he trained Edison as a telegraph operator. Edison's first telegraphy job away from Port Huron was at Stratford Junction, Ontario, on the Grand Trunk Railway.

In 1866, at the age of 19, Edison moved to Louisville, Kentucky, where, as an employee of Western Union, he worked the Associated Press bureau news wire. Edison requested the night shift, which allowed him plenty of time to spend at his two favorite pastimes—reading and experimenting. Eventually, the latter pre-occupation cost him his job. One night in 1867, he was working with a lead–acid battery when he spilled sulfuric acid onto the floor. It ran between the floorboards and onto his boss's desk below. The next morning Edison was fired.

One of his mentors during those early years was a fellow telegrapher and inventor named Franklin Leonard Pope, who allowed the impoverished youth to live and work in the basement of his Elizabeth, New Jersey, home. Some of Edison's earliest inventions were related to telegraphy, including a stock ticker. His first patent was for the electric vote recorder, (U.S. Patent 90,646), which was granted on June 1, 1869.

Beginning his career

Edison began his career as an inventor in Newark, New Jersey, with the automatic repeater and his other improved telegraphic devices, but the invention that first gained him notice was the phonograph in 1877. This accomplishment was so unexpected by the public at large as to appear almost magical. Edison became known as "The Wizard of Menlo Park," New Jersey.

His first phonograph recorded on tinfoil around a grooved cylinder. Despite its limited sound quality and that the recordings could be played only a few times, the phonograph made Edison a celebrity. Joseph Henry, president of the National Academy of Sciences and one of the most renowned electrical scientists in the US, described Edison as "the most ingenious inventor in this country... or in any other". In April 1878, Edison travelled to Washington to demonstrate the phonograph before the National Academy of Sciences, Congressmen, Senators and US President Hayes. The Washington Post described Edison as a "genius" and his presentation as "a scene... that will live in history". Although Edison obtained a patent for the phonograph in 1878, he did little to develop it until Alexander Graham Bell, Chichester Bell, and Charles Tainter produced a phonograph-like device in the 1880s that used wax-coated cardboard cylinders.

First Invention

Edison did not invent the first electric light bulb, but instead invented the first commercially practical incandescent light. Many earlier inventors had previously devised incandescent lamps, including Alessandro Volta's demonstration of a glowing wire in 1800 and inventions by Henry Woodward and Mathew Evans. Others who developed early and commercially impractical incandescent electric lamps included Humphry Davy, James Bowman Lindsay, Moses G. Farmer, William E. Sawyer, Joseph Swan and Heinrich Göbel. Some of these early bulbs had such flaws as an extremely short life, high expense to produce, and high electric current drawn, making them difficult to apply on a large scale commercially.

After many experiments, first with carbon filaments in the early 1880s and then with platinum and other metals, in the end Edison returned to a carbon filament. The first successful test was on October 22, 1879;:186 it lasted 13.5 hours. Edison continued to improve this design and by November 4, 1879, filed for U.S. patent 223,898 (granted on January 27, 1880) for an electric lamp using "a carbon filament or strip coiled and connected to platina contact wires".

Although the patent described several ways of creating the carbon filament including "cotton and linen thread, wood splints, papers coiled in various ways", it was not until several months after the patent was granted that Edison and his team discovered a carbonized bamboo filament that could last over 1,200 hours. The idea of using this particular raw material originated from Edison's recalling his examination of a few threads from a bamboo fishing pole while relaxing on the shore of Battle Lake in the present-day state of Wyoming, where he and other members of a scientific team had traveled so that they could clearly observe a total eclipse of the sun on July 29, 1878, from the Continental Divide.

In 1878, Edison formed the Edison Electric Light Company in New York City with several financiers, including J. P. Morgan and the members of the Vanderbilt family. Edison made the first public demonstration of his incandescent light bulb on December 31, 1879, in Menlo Park. It was during this time that he said: "We will make electricity so cheap that only the rich will burn candles."

Henry Villard, president of the Oregon Railroad and Navigation Company, had attended Edison's 1879 demonstration. Villard quickly became impressed and requested Edison install his electric lighting system aboard his company's new steamer, the Columbia. Although hesitant at first, Edison relented and agreed to Villard's request. Following most of its completion in May 1880, the Columbia was sent to New York City, where Edison and his personnel installed Columbia's new lighting system. Due to this, the Columbia became Edison's first commercial application for his incandescent light bulb. The Edison equipment was eventually removed from Columbia in 1895.

Lewis Latimer joined the Edison Electric Light Company in 1884. Latimer had received a patent in January 1881 for the "Process of Manufacturing Carbons", an improved method for the production of carbon filaments for lightbulbs. Latimer worked as an engineer, a draftsman and an expert witness in patent litigation on electric lights.

George Westinghouse's company bought Philip Diehl's competing induction lamp patent rights (1882) for $25,000, forcing the holders of the Edison patent to charge a more reasonable rate for the use of the Edison patent rights and lowering the price of the electric lamp.

On October 8, 1883, the US patent office ruled that Edison's patent was based on the work of William Sawyer and was therefore invalid. Litigation continued for nearly six years, until October 6, 1889, when a judge ruled that Edison's electric-light improvement claim for "a filament of carbon of high resistance" was valid. To avoid a possible court battle with Joseph Swan, whose British patent had been awarded a year before Edison's, he and Swan formed a joint company called Ediswan to manufacture and market the invention in Britain.

Mahen Theatre in Brno (in what is now the Czech Republic), which opened in 1882, was the first public building in the world to use Edison's electric lamps, with the installation supervised by Edison's assistant in the invention of the lamp, Francis Jehl. In September 2010, a sculpture of three giant light bulbs was erected in Brno, in front of the theatre.

Electric power distribution

Edison patented a system for electricity distribution in 1880, which was essential to capitalize on the invention of the electric lamp. On December 17, 1880, Edison founded the Edison Illuminating Company. The company established the first investor-owned electric utility in 1882 on Pearl Street Station, New York City. It was on September 4, 1882, that Edison switched on his Pearl Street generating station's electrical power distribution system, which provided 110 volts direct current (DC) to 59 customers in lower Manhattan.

Earlier in the year, in January 1882, he had switched on the first steam-generating power station at Holborn Viaduct in London. The DC supply system provided electricity supplies to street lamps and several private dwellings within a short distance of the station. On January 19, 1883, the first standardized incandescent electric lighting system employing overhead wires began service in Roselle, New Jersey.

Nikola Tesla worked for Edison for two years at the Continental Edison Company in France starting in 1882, and another year at the Edison Machine Works in New York City ending in a disagreement over pay.

War of currents

Edison's true success, like that of his friend Henry Ford, was in his ability to maximize profits through establishment of mass-production systems and intellectual property rights. George Westinghouse and Edison became adversaries because of Edison's promotion of direct current (DC) for electric power distribution instead of the more easily transmitted alternating current (AC) system promoted by Westinghouse. Unlike DC, AC could be stepped up to very high voltages with transformers, sent over thinner and cheaper wires, and stepped down again at the destination for distribution to users.

In 1887, there were 121 Edison power stations in the United States delivering DC electricity to customers. When the limitations of DC were discussed by the public, Edison launched a propaganda campaign to convince people that AC was far too dangerous to use. The problem with DC was that the power plants could economically deliver DC electricity only to customers within about one and a half miles (about 2.4 km) from the generating station, so that it was suitable only for central business districts. When George Westinghouse suggested using high-voltage AC instead, as it could carry electricity hundreds of miles with marginal loss of power, Edison waged a "War of Currents" to prevent AC from being adopted.

The war against AC led him to become involved in the development and promotion of the electric chair (using AC) as an attempt to portray AC to have greater lethal potential than DC. Edison went on to carry out a brief but intense campaign to ban the use of AC or to limit the allowable voltage for safety purposes. As part of this campaign, Edison's employees publicly electrocuted stray or unwanted animals to demonstrate the dangers of AC; alternating electric currents are slightly more dangerous in that frequencies near 60 Hz have a markedly greater potential for inducing fatal "cardiac fibrillation" than do direct currents. On one of the more notable occasions, in 1903, Edison's workers electrocuted Topsy the elephant at Luna Park, near Coney Island, after she had killed several men and her owners wanted her put to death. His company filmed the electrocution.

AC replaced DC in most instances of generation and power distribution, enormously extending the range and improving the efficiency of power distribution. Though widespread use of DC ultimately lost favor for distribution, it exists today primarily in long-distance high-voltage direct current (HVDC) transmission systems. Low-voltage DC distribution continued to be used in high-density downtown areas for many years but was eventually replaced by AC low-voltage network distribution in many of them.

DC had the advantage that large battery banks could maintain continuous power through brief interruptions of the electric supply from generators and the transmission system. Utilities such as Commonwealth Edison in Chicago had rotary converters or motor-generator sets, which could change DC to AC and AC to various frequencies in the early to mid-20th century. Utilities supplied rectifiers to convert the low voltage AC to DC for such DC loads as elevators, fans and pumps. There were still 1,600 DC customers in downtown New York City as of 2005, and service was finally discontinued only on November 14, 2007. Most subway systems are still powered by direct current.

Alfred Nobel

About Alfred Nobel

Alfred Bernhard Nobel (Swedish pronunciation: [ˈalfrɛd noˈbɛl] About this sound listen (help·info); 21 October 1833 – 10 December 1896) was a Swedish chemist, engineer, innovator, and armaments manufacturer.

He was the inventor of dynamite. Nobel also owned Bofors, which he had redirected from its previous role as primarily an iron and steel producer to a major manufacturer of cannon and other armaments. Nobel held 350 different patents, dynamite being the most famous. His fortune was used posthumously to institute the Nobel Prizes. The synthetic element nobelium was named after him. His name also survives in modern-day companies such as Dynamit Nobel and AkzoNobel, which are descendants of or mergers with companies Nobel himself established.

Life and career

Born in Stockholm, Alfred Nobel was the fourth son of Immanuel Nobel (1801–1872), an inventor and engineer, and Karolina Andriette (Ahlsell) Nobel (1805–1889). The couple married in 1827 and had eight children. The family was impoverished, and only Alfred and his three brothers survived past childhood. Through his father, Alfred Nobel was a descendant of the Swedish scientist Olaus Rudbeck (1630–1702), and in his turn the boy was interested in engineering, particularly explosives, learning the basic principles from his father at a young age. His interest in technology was inherited from his father, an alumnus of Royal Institute of Technology in Stockholm.

Following various business failures, Nobel's father moved to Saint Petersburg in 1837 and grew successful there as a manufacturer of machine tools and explosives. He invented modern plywood and started work on the "torpedo". In 1842, the family joined him in the city. Now prosperous, his parents were able to send Nobel to private tutors and the boy excelled in his studies, particularly in chemistry and languages, achieving fluency in English, French, German, and Russian. For 18 months, from 1841 to 1842, Nobel went to the only school he ever attended as a child, the Jacobs Apologistic School in Stockholm.

As a young man, Nobel studied with chemist Nikolai Zinin; then, in 1850, went to Paris to further the work; and, at 18, he went to the United States for four years to study chemistry, collaborating for a short period under inventor John Ericsson, who designed the American Civil War ironclad USS Monitor. Nobel filed his first patent, for a gas meter, in 1857.

The family factory produced armaments for the Crimean War (1853–1856); but, had difficulty switching back to regular domestic production when the fighting ended and they filed for bankruptcy. In 1859, Nobel's father left his factory in the care of the second son, Ludvig Nobel (1831–1888), who greatly improved the business. Nobel and his parents returned to Sweden from Russia and Nobel devoted himself to the study of explosives, and especially to the safe manufacture and use of nitroglycerine (discovered in 1847 by Ascanio Sobrero, one of his fellow students under Théophile-Jules Pelouze at the University of Turin). Nobel invented a detonator in 1863; and, in 1865, he designed the blasting cap.

On 3 September 1864, a shed, used for the preparation of nitroglycerin, exploded at the factory in Heleneborg Stockholm, killing five people, including Nobel's younger brother Emil. Dogged by more minor accidents but unfazed, Nobel went on to build further factories, focusing on improving the stability of the explosives he was developing. Nobel invented dynamite in 1867, a substance easier and safer to handle than the more unstable nitroglycerin. Dynamite was patented in the US and the UK and was used extensively in mining and the building of transport networks internationally. In 1875 Nobel invented gelignite, more stable and powerful than dynamite, and in 1887 patented ballistite, a forerunner of cordite.

Nobel was elected a member of the Royal Swedish Academy of Sciences in 1884, the same institution that would later select laureates for two of the Nobel prizes, and he received an honorary doctorate from Uppsala University in 1893.

Nobel's brothers Ludvig and Robert exploited oilfields along the Caspian Sea and became hugely rich in their own right. Nobel invested in these and amassed great wealth through the development of these new oil regions. During his life Nobel issued 350 patents internationally and by his death had established 90 armaments factories, despite his belief in pacifism.

In 1888, the death of his brother Ludvig caused several newspapers to publish obituaries of Alfred in error. A French obituary stated "Le marchand de la mort est mort" ("The merchant of death is dead").

In 1891, following the death of his mother and his brother Ludvig and the end of a longstanding relationship, Nobel moved from Paris to San Remo, Italy. Suffering from angina, Nobel died at home, of a cerebral hemorrhage in 1896. Unbeknownst to his family, friends or colleagues, he had left most of his wealth in trust, in order to fund the awards that would become known as the Nobel Prizes. He is buried in Norra begravningsplatsen in Stockholm.