Saturday, October 27, 2012

Stephen William Hawking

Stephen Hawking, (8 January 1942) 

Stephen William Hawking, (born 8 January 1942) is a British theoretical physicist and author. His significant scientific works to date have been a collaboration with Roger Penrose on theorems on gravitational singularities in the framework of general relativity, and the theoretical prediction that black holes should emit radiation, often called Hawking radiation.

He is an Honorary Fellow of the Royal Society of Arts, a lifetime member of the Pontifical Academy of Sciences, and a recipient of thePresidential 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. Subsequently, he became research director at the university's Centre for Theoretical Cosmology.

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 neurone disease related to amyotrophic lateral sclerosis, a condition that has progressed over the years. He is now almost entirely paralysed and communicates through a speech generating device. He married twice and has three children.



Life & Character - Stephen William Hawking was born on 8 January 1942 (300 years after the death of Galileo) in Oxford, England. His parents' house was in north London, but during the second world war, Oxford was considered a safer place to have babies. When he was eight, his family moved to St. Albans, a town about 20 miles north of London. At the age of eleven, Stephen went to St. Albans School and then on to University College, Oxford; his father's old college. Stephen wanted to study Mathematics, although his father would have preferred medicine. Mathematics was not available at University College, so he pursued Physics instead. After three years and not very much work, he was awarded a first class honours degree in Natural Science.
Stephen then went on to Cambridge to do research in Cosmology, there being no one working in that area in Oxford at the time. His supervisor was Denis Sciama, although he had hoped to get Fred Hoyle who was working in Cambridge. After gaining his Ph.D. he became first a Research Fellow and later on a Professorial Fellow at Gonville and Caius College. After leaving the Institute of Astronomy in 1973, Stephen came to the Department of Applied Mathematics and Theoretical Physics in 1979, and held the post of Lucasian Professor of Mathematics from 1979 until 2009. The chair was founded in 1663 with money left in the will of the Reverend Henry Lucas who had been the Member of Parliament for the University. It was first held by Isaac Barrow and then in 1669 by Isaac Newton. Stephen is still an active part of Cambridge University and retains an office at the Department for Applied Maths and Theoretical Physics . His title is now Director of Research at the Centre for Theoretical Cosmology.

Stephen Hawking has worked on the basic laws which govern the universe. With Roger Penrose he showed that Einstein's General Theory of Relativity implied space and time would have a beginning in the Big Bang and an end in black holes. These results indicated that it was necessary to unify General Relativity with Quantum Theory, the other great Scientific development of the first half of the 20th Century. One consequence of such a unification that he discovered was that black holes should not be completely black, but rather should emit radiation and eventually evaporate and disappear. Another conjecture is that the universe has no edge or boundary in imaginary time. This would imply that the way the universe began was completely determined by the laws of science.
His many publications include The Large Scale Structure of Spacetime with G F R Ellis, General Relativity: An Einstein Centenary Survey, with W Israel, and 300 Years of Gravity, with W Israel. Stephen Hawking has three popular books published; his best seller A Brief History of Time, Black Holes and Baby Universes and Other Essays, The Universe in a Nutshell, and most recently in 2010, The Grand Design.

Professor Hawking has twelve honorary degrees. He was awarded the CBE in 1982, and was made a Companion of Honour in 1989. He is the recipient of many awards, medals and prizes, is a Fellow of The Royal Society and a Member of the US National Academy of Sciences.

Stephen was diagnosed with ALS, a form of Motor Neurone Disease, shortly after his 21st birthday. In spite of being wheelchair bound and dependent on a computerised voice system for communication Stephen Hawking continues to combine family life (he has three children and three grandchildren), and his research into theoretical physics together with an extensive programme of travel and public lectures. He still hopes to make it into space one day.

Leonardo Da Vinci

Leonardo da Vinci (April 15, 1452 – May 2, 1519)



Leonardo di ser Piero da Vinci (April 15, 1452 – May 2, 1519) was an Italian Renaissance polymath: painter, sculptor, architect, musician, scientist, mathematician, engineer, inventor, anatomist, geologist, cartographer,botanist, and writer. His genius, perhaps more than that of any other figure, epitomized the Renaissance humanist ideal. Leonardo has often been described as the archetype of the Renaissance Man, a man of "unquenchable curiosity" and "feverishly inventive imagination". He is widely considered to be one of the greatest painters of all time and perhaps the most diversely talented person ever to have lived. According to art historian Helen Gardner, the scope and depth of his interests were without precedent and "his mind and personality seem to us superhuman, the man himself mysterious and remote". Marco Rosci states that while there is much speculation about Leonardo, his vision of the world is essentially logical rather than mysterious, and that the empirical methods he employed were unusual for his time.
Born out of wedlock to a notary, Piero da Vinci, and a peasant woman, Caterina, at Vinci in the region of Florence, Leonardo was educated in the studio of the renowned Florentine painter, Verrocchio. Much of his earlier working life was spent in the service of Ludovico il Moro in Milan. He later worked in Rome, Bologna and Venice, and he spent his last years in France at the home awarded him by Francis I.
Leonardo was and is renowned primarily as a painter. Among his works, the Mona Lisa is the most famous and most parodied portrait and The Last Supper the most reproduced religious painting of all time, with their fame approached only by Michelangelo's The Creation of Adam. Leonardo's drawing of the Vitruvian Man is also regarded as a cultural icon, being reproduced on items as varied as the euro, textbooks, and T-shirts. Perhaps fifteen of his paintings survive, the small number because of his constant, and frequently disastrous, experimentation with new techniques, and his chronic procrastination. Nevertheless, these few works, together with his notebooks, which contain drawings, scientific diagrams, and his thoughts on the nature of painting, compose a contribution to later generations of artists rivalled only by that of his contemporary, Michelangelo.
Leonardo is revered for his technological ingenuity. He conceptualised a helicopter, a tank, concentrated solar power, a calculator, and the double hull, and he outlined a rudimentary theory of plate tectonics. Relatively few of his designs were constructed or were even feasible during his lifetime, but some of his smaller inventions, such as an automated bobbin winder and a machine for testing the tensile strength of wire, entered the world of manufacturing unheralded. He made important discoveries in anatomy, civil engineering, optics, and hydrodynamics, but he did not publish his findings and they had no direct influence on later science.



Life & Character - Born on April 15, 1452, in Vinci, Italy, Leonardo da Vinci was the love child of a landowner and a peasant girl. Raised by his father, he began apprenticing at the age of 14 under the artist Verrocchio. Within six years, he was a master artist and began taking commissions from wealthy clients. His best-known works are two of the most famous paintings of all time, the Mona Lisa and The Last Supper. His scientific inquiries fill 13,000 pages, ranging from anatomy to war machines.

Humble Beginnings

Born out of wedlock, the love child of a respected notary and a young peasant woman, Leonardo da Vinci (b. April 15, 1452, in Vinci, Italy) was raised by his father, Ser Piero, and his stepmothers. At the age of 14, Leonardo began apprenticing with the artist Verrocchio. For six years, he learned a wide breadth of technical skills, including metalworking, leather arts, carpentry, drawing and sculpting. By the age of 20, he qualified as a master artist in the Guild of St. Luke and established his own workshop.
Florentine court records show that he was charged with and acquitted of sodomy at the age of 22, and for two years, his whereabouts went entirely undocumented.


Meteoric Rise
In 1482, Lorenzo de’ Medici, a man from a prominent Italian family, commissioned Leonardo to create a silver lyre and bring it to Ludovico il Moro, the Duke of Milan, as a gesture of peace. Leonardo did so and then wrote Ludovico a letter describing how his engineering and artistic talents would be of great service to Ludovico’s court. His letter successfully endeared him to Ludovico, and from 1482 until 1499, Leonardo was commissioned to work on a great many projects. It was during this time that he painted The Last Supper. Leonardo’s most well-known painting, arguably the most famous painting in the world, the Mona Lisa, was a privately commissioned work and was completed sometime between 1505 and 1507.


Renaissance Man
Leonardo has been called a genius and the archetypal Renaissance man; his talents extended far beyond his artistic works. Like many leaders of Renaissance humanism, he did not see a divide between science and art. His observations and inventions were recorded in 13,000 pages of notes and drawings, including designs for flying machines (some 400 years before the Wright brothers’ first success), plant studies, war machinery, anatomy and architecture. His ideas were mainly theoretical explanations, laid out in exacting detail, but they were rarely experimental. His drawings of a fetus in utero, the heart and vascular system, sex organs, and other bone and muscular structures, are some of the first on human record. One of his last commissioned works was a mechanical lion that could walk and open its chest to reveal a bouquet of lilies. On May 2, 1519, Leonardo’s first assistant and perhaps his lover, Francesco Melzi, became the principal heir and executor of his estate.


Friday, October 26, 2012

Albert Einstien

Albert Einstein (14 March 1879 – 18 April 1955)

Albert Einstein (14 March 1879 – 18 April 1955) was a German-born theoretical physicist who developed the general theory of relativity, effecting a revolution in physics. For this achievement, Einstein is often regarded as the father ofmodern physics and the most influential physicist of the 20th century. While best known for his mass–energy equivalence formula E = mc2 (which has been dubbed "the world's most famous equation"), he received the 1921 Nobel Prize in Physics "for his services to theoretical physics, and especially for his discovery of the law of the photoelectric effect". The latter was pivotal in establishing quantum theory within physics.

Near the beginning of his career, Einstein thought that Newtonian mechanics was no longer enough to reconcile the laws of classical mechanics with the laws of the electromagnetic field. This led to the development of his special theory of relativity. He realized, however, that the principle of relativity could also be extended to gravitational fields, and with his subsequent theory of gravitation in 1916, he published a paper on the general theory of relativity. He continued to deal with problems of statistical mechanics and quantum theory, which led to his explanations of particle theory and the motion of molecules. He also investigated the thermal properties of light which laid the foundation of the photon theory of light. In 1917, Einstein applied the general theory of relativity to model the structure of the universe as a whole.

He was visiting the United States when Adolf Hitler came to power in 1933, and did not go back to Germany, where he had been a professor at theBerlin Academy of Sciences. He settled in the U.S., becoming a citizen in 1940. On the eve of World War II, he helped alert President Franklin D. Roosevelt that Germany might be developing an atomic weapon, and recommended that the U.S. begin similar research; this eventually led to what would become the Manhattan Project. Einstein was in support of defending the Allied forces, but largely denounced using the new discovery of nuclear fission as a weapon. Later, with the British philosopher Bertrand Russell, Einstein signed the Russell–Einstein Manifesto, which highlighted the danger of nuclear weapons. Einstein was affiliated with the Institute for Advanced Study in Princeton, New Jersey, until his death in 1955.

Einstein published more than 300 scientific papers along with over 150 non-scientific works. His great intellectual achievements and originality have made the word "Einstein" synonymous with genius.


Life & Character - Albert Einstein was born at Ulm, in Württemberg, Germany, on March 14, 1879. Six weeks later the family moved to Munich, where he later on began his schooling at the Luitpold Gymnasium. Later, they moved to Italy and Albert continued his education at Aarau, Switzerland and in 1896 he entered the Swiss Federal Polytechnic School in Zurich to be trained as a teacher in physics and mathematics. In 1901, the year he gained his diploma, he acquired Swiss citizenship and, as he was unable to find a teaching post, he accepted a position as technical assistant in the Swiss Patent Office. In 1905 he obtained his doctor's degree.

During his stay at the Patent Office, and in his spare time, he produced much of his remarkable work and in 1908 he was appointed Privatdozent in Berne. In 1909 he became Professor Extraordinary at Zurich, in 1911 Professor of Theoretical Physics at Prague, returning to Zurich in the following year to fill a similar post. In 1914 he was appointed Director of the Kaiser Wilhelm Physical Institute and Professor in the University of Berlin. He became a German citizen in 1914 and remained in Berlin until 1933 when he renounced his citizenship for political reasons and emigrated to America to take the position of Professor of Theoretical Physics at Princeton*. He became a United States citizen in 1940 and retired from his post in 1945.

After World War II, Einstein was a leading figure in the World Government Movement, he was offered the Presidency of the State of Israel, which he declined, and he collaborated with Dr. Chaim Weizmann in establishing the Hebrew University of Jerusalem.

Einstein always appeared to have a clear view of the problems of physics and the determination to solve them. He had a strategy of his own and was able to visualize the main stages on the way to his goal. He regarded his major achievements as mere stepping-stones for the next advance.

At the start of his scientific work, Einstein realized the inadequacies of Newtonian mechanics and his special theory of relativity stemmed from an attempt to reconcile the laws of mechanics with the laws of the electromagnetic field. He dealt with classical problems of statistical mechanics and problems in which they were merged with quantum theory: this led to an explanation of the Brownian movement of molecules. He investigated the thermal properties of light with a low radiation density and his observations laid the foundation of the photon theory of light.

In his early days in Berlin, Einstein postulated that the correct interpretation of the special theory of relativity must also furnish a theory of gravitation and in 1916 he published his paper on the general theory of relativity. During this time he also contributed to the problems of the theory of radiation and statistical mechanics.

In the 1920's, Einstein embarked on the construction of unified field theories, although he continued to work on the probabilistic interpretation of quantum theory, and he persevered with this work in America. He contributed to statistical mechanics by his development of the quantum theory of a monatomic gas and he has also accomplished valuable work in connection with atomic transition probabilities and relativistic cosmology.

After his retirement he continued to work towards the unification of the basic concepts of physics, taking the opposite approach, geometrisation, to the majority of physicists.

Einstein's researches are, of course, well chronicled and his more important works includeSpecial Theory of Relativity (1905), Relativity (English translations, 1920 and 1950), General Theory of Relativity (1916), Investigations on Theory of Brownian Movement (1926), and The Evolution of Physics (1938). Among his non-scientific works, About Zionism (1930), Why War?(1933), My Philosophy (1934), and Out of My Later Years (1950) are perhaps the most important.

Albert Einstein received honorary doctorate degrees in science, medicine and philosophy from many European and American universities. During the 1920's he lectured in Europe, America and the Far East and he was awarded Fellowships or Memberships of all the leading scientific academies throughout the world. He gained numerous awards in recognition of his work, including the Copley Medal of the Royal Society of London in 1925, and the Franklin Medal of the Franklin Institute in 1935.

Einstein's gifts inevitably resulted in his dwelling much in intellectual solitude and, for relaxation, music played an important part in his life. He married Mileva Maric in 1903 and they had a daughter and two sons; their marriage was dissolved in 1919 and in the same year he married his cousin, Elsa Löwenthal, who died in 1936. He died on April 18, 1955 at Princeton, New Jersey.

Sir Issac Newton



Isaac Newton (1642-1727)



Newton, Sir Isaac (1642-1727), English physicist, mathematician, astronomer, natural philosopher, alchemist and theologian, generally regarded as the most original and influential theorist in the history of science, who has been "considered by many to be the greatest and most influential scientist who ever lived." In addition to his invention of the infinitesimal calculus and a new theory of light and color, Newton transformed the structure of physical science with his three laws of motion and the law of universal gravitation. As the keystone of the scientific revolution of the 17th century, Newton's work combined the contributions of Copernicus, Kepler, Galileo, Descartes, and others into a new and powerful synthesis. Three centuries later the resulting structure - classical mechanics - continues to be a useful but no less elegant monument to his genius.


Life & Character - Isaac Newton was born prematurely on Christmas day 1642 (4 January 1643, New Style) in Woolsthorpe, a hamlet near Grantham in Lincolnshire. The posthumous son of an illiterate yeoman (also named Isaac), the fatherless infant was small enough at birth to fit 'into a quartpot.' When he was barely three years old Newton's mother, Hanna (Ayscough), placed her first born with his grandmother in order to remarry and raise a second family with Barnabas Smith, a wealthy rector from nearby North Witham. Much has been made of Newton's posthumous birth, his prolonged separation from his mother, and his unrivaled hatred of his stepfather. Until Hanna returned to Woolsthorpe in 1653 after the death of her second husband, Newton was denied his mother's attention, a possible clue to his complex character. Newton's childhood was anything but happy, and throughout his life he verged on emotional collapse, occasionally falling into violent and vindictive attacks against friend and foe alike.

With his mother's return to Woolsthorpe in 1653, Newton was taken from school to fulfill his birthright as a farmer. Happily, he failed in this calling, and returned to King's School at Grantham to prepare for entrance to Trinity College, Cambridge. Numerous anecdotes survive from this period about Newton's absent-mindedness as a fledging farmer and his lackluster performance as a student. But the turning point in Newton's life came in June 1661 when he left Woolsthorpe for Cambridge University. Here Newton entered a new world, one he could eventually call his own.

Although Cambridge was an outstanding center of learning, the spirit of the scientific revolution had yet to penetrate its ancient and somewhat ossified curriculum. Little is known of Newton's formal studies as an undergraduate, but he likely received large doses of Aristotle as well as other classical authors. And by all appearances his academic performance was undistinguished. In 1664 Isaac Barrow, Lucasian Professor of Mathematics at Cambridge, examined Newton's understanding of Euclid and found it sorely lacking. We now know that during his undergraduate years Newton was deeply engrossed in private study, that he privately mastered the works of René Descartes, Pierre Gassendi, Thomas Hobbes, and other major figures of the scientific revolution. A series of extant notebooks shows that by 1664 Newton had begun to master Descartes' Géométrie and other forms of mathematics far in advance of Euclid's Elements. Barrow, himself a gifted mathematician, had yet to appreciate Newton's genius.

In 1665 Newton took his bachelor's degree at Cambridge without honors or distinction. Since the university was closed for the next two years because of plague, Newton returned to Woolsthorpe in midyear. There, in the following 18 months, he made a series of original contributions to science. As he later recalled, 'All this was in the two plague years of 1665 and 1666, for in those days I was in my prime of age for invention, and minded mathematics and philosophy more than at any time since.' In mathematics Newton conceived his 'method of fluxions' (infinitesimal calculus), laid the foundations for his theory of light and color, and achieved significant insight into the problem of planetary motion, insights that eventually led to the publication of his Principia (1687).

In April 1667, Newton returned to Cambridge and, against stiff odds, was elected a minor fellow at Trinity. Success followed good fortune. In the next year he became a senior fellow upon taking his master of arts degree, and in 1669, before he had reached his 27th birthday, he succeeded Isaac Barrow as Lucasian Professor of Mathematics. The duties of this appointment offered Newton the opportunity to organize the results of his earlier optical researches, and in 1672, shortly after his election to the Royal Society, he communicated his first public paper, a brilliant but no less controversial study on the nature of color.

In the first of a series of bitter disputes, Newton locked horns with the society's celebrated curator of experiments, the bright but brittle Robert Hooke. The ensuing controversy, which continued until 1678, established a pattern in Newton's behavior. After an initial skirmish, he quietly retreated. Nonetheless, in 1675 Newton ventured another yet another paper, which again drew lightning, this time charged with claims that he had plagiarized from Hooke. The charges were entirely ungrounded. Twice burned, Newton withdrew.

In 1678, Newton suffered a serious emotional breakdown, and in the following year his mother died. Newton's response was to cut off contact with others and engross himself in alchemical research. These studies, once an embarrassment to Newton scholars, were not misguided musings but rigorous investigations into the hidden forces of nature. Newton's alchemical studies opened theoretical avenues not found in the mechanical philosophy, the world view that sustained his early work. While the mechanical philosophy reduced all phenomena to the impact of matter in motion, the alchemical tradition upheld the possibility of attraction and repulsion at the particulate level. Newton's later insights in celestial mechanics can be traced in part to his alchemical interests. By combining action-at-a-distance and mathematics, Newton transformed the mechanical philosophy by adding a mysterious but no less measurable quantity, gravitational force.

In 1666, as tradition has it, Newton observed the fall of an apple in his garden at Woolsthorpe, later recalling, 'In the same year I began to think of gravity extending to the orb of the Moon.' Newton's memory was not accurate. In fact, all evidence suggests that the concept of universal gravitation did not spring full-blown from Newton's head in 1666 but was nearly 20 years in gestation. Ironically, Robert Hooke helped give it life. In November 1679, Hooke initiated an exchange of letters that bore on the question of planetary motion. Although Newton hastily broke off the correspondence, Hooke's letters provided a conceptual link between central attraction and a force falling off with the square of distance. Sometime in early 1680, Newton appears to have quietly drawn his own conclusions.

Meanwhile, in the coffeehouses of London, Hooke, Edmund Halley, and Christopher Wren struggled unsuccessfully with the problem of planetary motion. Finally, in August 1684, Halley paid a legendary visit to Newton in Cambridge, hoping for an answer to his riddle: What type of curve does a planet describe in its orbit around the sun, assuming an inverse square law of attraction? When Halley posed the question, Newton's ready response was 'an ellipse.' When asked how he knew it was an ellipse Newton replied that he had already calculated it. Although Newton had privately answered one of the riddles of the universe--and he alone possessed the mathematical ability to do so--he had characteristically misplaced the calculation. After further discussion he promised to send Halley a fresh calculation forthwith. In partial fulfillment of his promise Newton produced his De Motu of 1684. From that seed, after nearly two years of intense labor, the Philosophiae Naturalis Principia Mathematica appeared. Arguably, it is the most important book published in the history of science. But if the Principia was Newton's brainchild, Hooke and Halley were nothing less than midwives.

Although the Principia was well received, its future was cast in doubt before it appeared. Here again Hooke was center stage, this time claiming (not without justification) that his letters of 1679-1680 earned him a role in Newton's discovery. But to no effect. Newton was so furious with Hooke that he threatened to suppress Book III of the Principia altogether, finally denouncing science as 'an impertinently litigious lady.' Newton calmed down and finally consented to publication. But instead of acknowledging Hooke's contribution Newton systematically deleted every possible mention of Hooke's name. Newton's hatred for Hooke was consumptive. Indeed, Newton later withheld publication of his Opticks (1704) and virtually withdrew from the Royal Society until Hooke's death in 1703.

After publishing the Principia, Newton became more involved in public affairs. In 1689 he was elected to represent Cambridge in Parliament, and during his stay in London he became acquainted with John Locke, the famous philosopher, and Nicolas Fatio de Duillier, a brilliant young mathematician who became an intimate friend. In 1693, however, Newton suffered a severe nervous disorder, not unlike his breakdown of 1677-1678. The cause is open to interpretation: overwork; the stress of controversy; the unexplained loss of friendship with Fatio; or perhaps chronic mercury poisoning, the result of nearly three decades of alchemical research. Each factor may have played a role. We only know Locke and Samuel Pepys received strange and seemingly deranged letters that prompted concern for Newton's 'discomposure in head, or mind, or both.' Whatever the cause, shortly after his recovery Newton sought a new position in London. In 1696, with the help of Charles Montague, a fellow of Trinity and later earl of Halifax, Newton was appointed Warden and then Master of the Mint. His new position proved 'most proper,' and he left Cambridge for London without regret.

During his London years Newton enjoyed power and worldly success. His position at the Mint assured a comfortable social and economic status, and he was an active and able administrator. After the death of Hooke in 1703, Newton was elected president of the Royal Society and was annually reelected until his death. In 1704 he published his second major work, the Opticks, based largely on work completed decades before. He was knighted in 1705.

Although his creative years had passed, Newton continued to exercise a profound influence on the development of science. In effect, the Royal Society was Newton's instrument, and he played it to his personal advantage. His tenure as president has been described as tyrannical and autocratic, and his control over the lives and careers of younger disciples was all but absolute. Newton could not abide contradiction or controversy - his quarrels with Hooke provide singular examples. But in later disputes, as president of the Royal Society, Newton marshaled all the forces at his command. For example, he published Flamsteed's astronomical observations - the labor of a lifetime - without the author's permission; and in his priority dispute with Leibniz concerning the calculus, Newton enlisted younger men to fight his war of words, while behind the lines he secretly directed charge and countercharge. In the end, the actions of the Society were little more than extensions of Newton's will, and until his death he dominated the landscape of science without rival. He died in London on March 20, 1727 (March 31, New Style).