Heliocentrism Andreas Cellarius's illustration of the Copernican system, from the Harmonia Macrocosmica (1660). Heliocentrism, or heliocentricism,[1] is the astronomical model in which the Earth and planets revolve around a relatively stationary Sun at the center of the Solar System. The word comes from the Greek (ἥλιος helios "sun" and κέντρον kentron "center"). Historically, heliocentrism was opposed to geocentrism, which placed the Earth at the center. It was not until the 16th century that a fully predictive mathematical model of a heliocentric system was presented, by the Renaissance mathematician, astronomer, and Catholic cleric Nicolaus Copernicus of Poland, leading to the Copernican Revolution. With the observations of William Herschel, Friedrich Bessel, and others, astronomers realized that the sun was not the center of the universe as heliocentrists at the time of Copernicus had supposed. Early developments[edit] Greek and Hellenistic world[edit] Pythagoreans Aristarchus of Samos India[edit]
Alhazen In medieval Europe, he was honored as Ptolemaeus Secundus ("Ptolemy the Second")[10] or simply called "The Physicist".[11] He is also sometimes called al-Basri (Arabic: البصري) after Basra, his birthplace.[12] He spent most of his life close to the court of the Caliphate in Cairo and earned his living authoring various treatises and tutoring members of the nobilities.[13] Overview[edit] Biography[edit] Born c. 965 in Basra, which was then part of the Buyid emirate,[1] to an Arab family.[14][15] Legacy[edit] Front page of the Opticae Thesaurus, which included the first printed Latin translation of Alhazen's Book of Optics. Alhazen made significant contributions to optics, number theory, geometry, astronomy and natural philosophy. One of the major scientific anniversaries that will be celebrated during the 2015 International Year of Light is: the works on optics by Ibn Al-Haytham (1015). Book of Optics[edit] Main article: Book of Optics Theory of vision[edit] Alhazen on Iraqi 10 dinars G. A.
Second law of thermodynamics The second law of thermodynamics states that every process occurring in nature proceeds in the sense in which the sum of the entropies of all bodies taking part in the process is increased. In the limit, i.e. for reversible processes, the sum of the entropies remains unchanged.[1][2][3] The second law is an empirical finding that has been accepted as an axiom of thermodynamic theory. Statistical thermodynamics, classical or quantum, explains the law. The second law has been expressed in many ways. Introduction[edit] The first law of thermodynamics provides the basic definition of thermodynamic energy, also called internal energy, associated with all thermodynamic systems, but unknown in classical mechanics, and states the rule of conservation of energy in nature.[4][5] The concept of energy in the first law does not, however, account for the observation that natural processes have a preferred direction of progress. For mathematical analysis of processes, entropy is introduced as follows. .
Philosophiæ Naturalis Principia Mathematica Philosophiæ Naturalis Principia Mathematica, Latin for "Mathematical Principles of Natural Philosophy", often referred to as simply the Principia, is a work in three books by Sir Isaac Newton, in Latin, first published 5 July 1687.[1][2] After annotating and correcting his personal copy of the first edition,[3] Newton also published two further editions, in 1713 and 1726.[4] The Principia states Newton's laws of motion, forming the foundation of classical mechanics, also Newton's law of universal gravitation, and a derivation of Kepler's laws of planetary motion (which Kepler first obtained empirically). The Principia is "justly regarded as one of the most important works in the history of science".[5] The French mathematical physicist Alexis Clairaut assessed it in 1747: "The famous book of mathematical Principles of natural Philosophy marked the epoch of a great revolution in physics. Contents[edit] Expressed aim and topics covered[edit] In the preface of the Principia, Newton wrote[10]
Galileo Galilei Galileo Galilei (Italian pronunciation: [ɡaliˈlɛːo ɡaliˈlɛi]; 15 February 1564[3] – 8 January 1642), often known mononymously as Galileo, was an Italian physicist, mathematician, engineer, astronomer, and philosopher who played a major role in the scientific revolution during the Renaissance. His achievements include improvements to the telescope and consequent astronomical observations and support for Copernicanism. Galileo has been called the "father of modern observational astronomy",[4] the "father of modern physics",[5][6] the "father of science",[6][7] and "the father of modern science".[8] Early life Galileo was born in Pisa (then part of the Duchy of Florence), Italy, in 1564,[15] the first of six children of Vincenzo Galilei, a famous lutenist, composer, and music theorist, and Giulia Ammannati. Although a genuinely pious Roman Catholic,[17] Galileo fathered three children out of wedlock with Marina Gamba. Career as a scientist Galileo, Kepler and theories of tides
Occam's razor The sun, moon and other solar system planets can be described as revolving around the Earth. However that explanation's ideological and complex assumptions are completely unfounded compared to the modern consensus that all solar system planets revolve around the Sun. Ockham's razor (also written as Occam's razor and in Latin lex parsimoniae) is a principle of parsimony, economy, or succinctness used in problem-solving devised by William of Ockham (c. 1287 - 1347). It states that among competing hypotheses, the one with the fewest assumptions should be selected. Other, more complicated solutions may ultimately prove correct, but—in the absence of certainty—the fewer assumptions that are made, the better. Solomonoff's theory of inductive inference is a mathematically formalized Occam's Razor:[2][3][4][5][6][7] shorter computable theories have more weight when calculating the probability of the next observation, using all computable theories which perfectly describe previous observations.
James Clerk Maxwell James Clerk Maxwell FRS FRSE (13 June 1831 – 5 November 1879) was a Scottish[2][3] mathematical physicist.[4] His most notable achievement was to formulate the classical theory of electromagnetic radiation, bringing together for the first time electricity, magnetism, and light as manifestations of the same phenomenon. Maxwell's equations for electromagnetism have been called the "second great unification in physics"[5] after the first one realised by Isaac Newton. With the publication of A Dynamical Theory of the Electromagnetic Field in 1865, Maxwell demonstrated that electric and magnetic fields travel through space as waves moving at the speed of light. Maxwell proposed that light is an undulation in the same medium that is the cause of electric and magnetic phenomena.[6] The unification of light and electrical phenomena led to the prediction of the existence of radio waves. Life[edit] Early life, 1831–39[edit] Education, 1839–47[edit] Edinburgh Academy, where Maxwell was schooled ...
Zipf's law Zipf's law /ˈzɪf/, an empirical law formulated using mathematical statistics, refers to the fact that many types of data studied in the physical and social sciences can be approximated with a Zipfian distribution, one of a family of related discrete power law probability distributions. The law is named after the American linguist George Kingsley Zipf (1902–1950), who first proposed it (Zipf 1935, 1949), though the French stenographer Jean-Baptiste Estoup (1868–1950) appears to have noticed the regularity before Zipf.[1] It was also noted in 1913 by German physicist Felix Auerbach[2] (1856–1933). Motivation[edit] Zipf's law states that given some corpus of natural language utterances, the frequency of any word is inversely proportional to its rank in the frequency table. The same relationship occurs in many other rankings unrelated to language, such as the population ranks of cities in various countries, corporation sizes, income rankings, and so on. Theoretical review[edit] Formally, let:
Leonardo da Vinci Leonardo is revered for his technological ingenuity. He conceptualised flying machines, an armoured vehicle, concentrated solar power, an adding machine,[7] and the double hull, also outlining a rudimentary theory of plate tectonics. Relatively few of his designs were constructed or were even feasible during his lifetime,[nb 2] 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.[nb 3] He made substantial discoveries in anatomy, civil engineering, optics, and hydrodynamics, but he did not publish his findings and they had no direct influence on later science.[8] Life Childhood, 1452–1466 Leonardo's earliest known drawing, the Arno Valley (1473), Uffizi Verrocchio's workshop, 1466–1476 Professional life, 1476–1513 In 1482 Leonardo, who according to Vasari was a most talented musician,[25] created a silver lyre in the shape of a horse's head. Old age, 1513–1519 Personal life
Albert Einstein Albert Einstein (/ˈælbərt ˈaɪnʃtaɪn/; German: [ˈalbɐrt ˈaɪnʃtaɪn]; 14 March 1879 – 18 April 1955) was a German-born theoretical physicist. Einstein's work is also known for its influence on the philosophy of science.[4][5] He developed the general theory of relativity, one of the two pillars of modern physics (alongside quantum mechanics).[3][6]:274 Einstein is best known in popular culture for his mass–energy equivalence formula E = mc2 (which has been dubbed "the world's most famous equation").[7] He received the 1921 Nobel Prize in Physics for his "services to theoretical physics", in particular his discovery of the law of the photoelectric effect, a pivotal step in the evolution of quantum theory.[8] 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. Life Early life and education Death
Charles Darwin Charles Robert Darwin, FRS (/ˈdɑrwɪn/;[1] 12 February 1809 – 19 April 1882) was an English naturalist and geologist,[2] best known for his contributions to evolutionary theory.[I] He established that all species of life have descended over time from common ancestors,[3] and in a joint publication with Alfred Russel Wallace introduced his scientific theory that this branching pattern of evolution resulted from a process that he called natural selection, in which the struggle for existence has a similar effect to the artificial selection involved in selective breeding.[4] Darwin published his theory of evolution with compelling evidence in his 1859 book On the Origin of Species, overcoming scientific rejection of earlier concepts of transmutation of species.[5][6] By the 1870s the scientific community and much of the general public had accepted evolution as a fact. Biography Early life and education Painting of seven-year-old Charles Darwin in 1816. Voyage of the Beagle Death and funeral Works
Edward Witten Edward Witten (/ˈwɪtən/; born August 26, 1951) is an American theoretical physicist and professor of mathematical physics at the Institute for Advanced Study in Princeton, New Jersey. Witten is a researcher in string theory, quantum gravity, supersymmetric quantum field theories, and other areas of mathematical physics. Birth and education[edit] Witten was born in Baltimore, Maryland. Witten attended the Park School of Baltimore (class of '68), and received his Bachelor of Arts with a major in history and minor in linguistics from Brandeis University in 1971. Witten attended the University of Wisconsin–Madison for one semester as an economics graduate student before dropping out.[4] He returned to academia, enrolling in applied mathematics at Princeton University in 1973, then shifting departments and receiving a Ph.D. in physics in 1976 under David Gross,[4] the 2004 Nobel laureate in Physics. Research[edit] Fields medal work[edit] M-theory[edit] Other work[edit] Awards and honors[edit]