FACTOID # 28: Austin, Texas has more people than Alaska.

 Home Encyclopedia Statistics States A-Z Flags Maps FAQ About

 WHAT'S NEW

SEARCH ALL

Search encyclopedia, statistics and forums:

(* = Graphable)

Encyclopedia > Galileo Galilei
Galileo Galilei

Portrait of Galileo Galilei by Giusto Sustermans
Born February 15, 1564[1]
Pisa, Italy[1]
Died January 8, 1642 (aged 77)[1]
Arcetri, Italy[1]
Residence Grand Duchy of Tuscany
Field Astronomy, Physics and Mathematics
Alma mater University of Pisa
Known for Kinematics
Telescope
Solar System
Religion Roman Catholic

Galileo has been called the "father of modern observational astronomy",[3] the "father of modern physics",[4] the "father of science",[4] and “the Father of Modern Science.”[5] The motion of uniformly accelerated objects, taught in nearly all high school and introductory college physics courses, was studied by Galileo as the subject of kinematics. His contributions to observational astronomy include the discovery of the four largest satellites of Jupiter, named the Galilean moons in his honour, and the observation and analysis of sunspots. Galileo also worked in applied science and technology, improving compass design. For other uses, see Astronomy (disambiguation). ... A magnet levitating above a high-temperature superconductor demonstrates the Meissner effect. ... Part of a scientific laboratory at the University of Cologne. ... Kinematics (Greek ÎºÎ¹Î½ÎµÎ¹Î½,kinein, to move) is a branch of mechanics which describes the motion of objects without the consideration of the masses or forces that bring about the motion. ... Jupiters 4 Galilean moons, in a composite image comparing their sizes and the size of Jupiter (Great Red Spot visible). ... 400 year sunspot history A sunspot is a region on the Suns surface (photosphere) that is marked by a lower temperature than its surroundings, and intense magnetic activity. ... This article is about the navigational instrument. ...

Galileo was born in Pisa (then part of the Grand Duchy of Tuscany), the first of six children of Vincenzo Galilei, a famous lutenist and music theorist, and Giulia Ammannati. Although he seriously considered the priesthood as a young man, he enrolled for a medical degree at the University of Pisa at his father's urging. He did not complete this degree, but instead studied mathematics and in 1589 was appointed to the chair of mathematics in Pisa. In 1591 his father died and he was entrusted with the care of his younger brother Michelagnolo. In 1592 he moved to the University of Padua, teaching geometry, mechanics, and astronomy until 1610. During this period Galileo made significant discoveries in both pure science (for example, kinematics of motion, and astronomy) and applied science (for example, strength of materials, improvement of the telescope). His multiple interests included the study of astrology, which in premodern disciplinary practice was seen as correlated to the studies of mathematics and astronomy.[7] Leaning Tower of Pisa. ... The Grand Duchy of Tuscany was a state in central Italy which came into existence in 1569, replacing the Duchy of Florence, which had been created out of the old Republic of Florence in 1532, and which annexed the Republic of Siena in 1557. ... Vincenzo Galilei (1520 â€“ July 2, 1591) was an Italian lutenist, composer, and music theorist, and the father of the famous astronomer Galileo Galilei. ... The lute is a plucked string instrument with a fretted neck and a deep round back. ... Music theory is a field of study that investigates the nature or mechanics of music. ... Michelagnolo Galilei (also sometimes spelled Michelangelo) (December 18, 1575 â€“ January 3, 1631) was an Italian composer and lutenist of the late Renaissance and early Baroque eras, active mainly in Bavaria and Poland. ... Gymnasivm Patavinum: The Universitys main Bo palace shown in a 1654 woodcut The University of Padua (Italian UniversitÃ  degli Studi di Padova, UNIPD) located in Padua, Italy was founded in 1222. ... Calabi-Yau manifold Geometry (Greek Î³ÎµÏ‰Î¼ÎµÏ„ÏÎ¯Î±; geo = earth, metria = measure) is a part of mathematics concerned with questions of size, shape, and relative position of figures and with properties of space. ... For other uses, see Mechanic (disambiguation). ... For other uses, see Astronomy (disambiguation). ... Hand-coloured version of the anonymous Flammarion woodcut (1888). ...

Although a devout Roman Catholic, Galileo fathered three children out of wedlock with Marina Gamba. They had two daughters (Virginia in 1600 and Livia in 1601) and one son (Vincenzio, in 1606). Because of their illegitimate birth, their father considered the girls unmarriageable. Their only worthy alternative was the religious life. Both girls were sent to the convent of San Matteo in Arcetri and remained there for the rest of their lives.[8] Virginia (b. 1600) took the name Maria Celeste upon entering the convent. She died on April 2, 1634, and is buried with Galileo at the Basilica di Santa Croce di Firenze. Livia (b. 1601) took the name Suor Arcangela and was ill for most of her life. Vincenzio (b. 1606) was later legitimized and married Sestilia Bocchineri. The Roman Catholic Church, most often spoken of simply as the Catholic Church, is the largest Christian church, with over one billion members. ... It has been suggested that this article or section be merged with Legitimacy (law). ... Marina Gamba was the lover of Galileo Galilei. ... Sister Maria Celeste, born Virginia Gamba on August 16, 1600, was the daughter of Galileo Galilei and Marina Gamba. ... is the 92nd day of the year (93rd in leap years) in the Gregorian calendar. ... Events Moses Amyrauts Traite de la predestination is published CuraÃ§ao captured by the Dutch Treaty of Polianovska First meeting of the AcadÃ©mie franÃ§aise The witchcraft affair at Loudun Jean Nicolet lands at Green Bay, Wisconsin Opening of Covent Garden Market in London English establish a settlement... FaÃ§ade. ...

## Scientific methods

Galileo Galilei pioneered the use of quantitative experiments whose results could be analyzed with mathematical precision (More typical of science at the time were the qualitative studies of William Gilbert, on magnetism and electricity). Galileo's father, Vincenzo Galilei, a lutenist and music theorist, had performed experiments establishing perhaps the oldest known non-linear relation in physics: for a stretched string, the pitch varies as the square root of the tension. These observations lay within the framework of the Pythagorean tradition of music, well-known to instrument makers, which included the fact that subdividing a string by a whole number produces a harmonious scale. Thus, a limited amount of mathematics had long related music and physical science, and young Galileo could see his own father's observations expand on that tradition. Galileo is perhaps the first to clearly state that the laws of nature are mathematical. In The Assayer he wrote "Philosophy is written in this grand book, the universe ... It is written in the language of mathematics, and its characters are triangles, circles, and other geometric figures; ...".[10] His mathematical analyses are a further development of a tradition employed by late scholastic natural philosophers, which Galileo learned when he studied philosophy.[11] Although he tried to remain loyal to the Catholic Church, his adherence to experimental results, and their most honest interpretation, led to a rejection of blind allegiance to authority, both philosophical and religious, in matters of science. In broader terms, this aided to separate science from both philosophy and religion; a major development in human thought. For other persons named William Gilbert, see William Gilbert (disambiguation). ... Vincenzo Galilei (1520 â€“ July 2, 1591) was an Italian lutenist, composer, and music theorist, and the father of the famous astronomer Galileo Galilei. ... A medieval era lute. ... Pythagoras of Samos (Greek: ; between 580 and 572 BCâ€“between 500 and 490 BC) was an Ionian (Greek) philosopher[1] and founder of the religious movement called Pythagoreanism. ... In 1616 Galileo[1] may have been silenced on Copernicanism, but he bounced back with gusto in 1623. ... For other uses, see Philosophy (disambiguation). ...

By the standards of his time, Galileo was often willing to change his views in accordance with observation. Philosopher of science Paul Feyerabend also noted the supposedly improper aspects of Galileo's methodology, but he argued that Galileo's methods could be justified retroactively by their results. The bulk of Feyerabend's major work, Against Method (1975), was devoted to an analysis of Galileo, using his astronomical research as a case study to support Feyerabend's own anarchistic theory of scientific method. As he put it: 'Aristotelians [...] demanded strong empirical support while the Galileans were content with far-reaching, unsupported and partially refuted theories. I do not criticize them for that; on the contrary, I favour Niels Bohr's "this is not crazy enough."'[12] In order to perform his experiments, Galileo had to set up standards of length and time, so that measurements made on different days and in different laboratories could be compared in a reproducible fashion. For measurements of particularly short intervals of time, Galileo sang songs with whose timing he was familiar. Paul Karl Feyerabend (January 13, 1924 â€“ February 11, 1994) was an Austrian-born philosopher of science best known for his work as a professor of philosophy at the University of California, Berkeley, where he worked for three decades (1958-1989). ... Scientific method is a body of techniques for investigating phenomena, acquiring new knowledge, or correcting and integrating previous knowledge. ... Niels Henrik David Bohr (October 7, 1885 â€“ November 18, 1962) was a Danish physicist who made fundamental contributions to understanding atomic structure and quantum mechanics, for which he received the Nobel Prize in 1922. ...

Galileo showed a remarkably modern appreciation for the proper relationship between mathematics, theoretical physics, and experimental physics. He understood the parabola, both in terms of conic sections and in terms of the ordinate (y) varying as the square of the abscissa (x). Galilei further asserted that the parabola was the theoretically-ideal trajectory for uniformly accelerated motion, in the absence of friction and other disturbances. He also noted that there are limits to the validity of this theory, stating that it was appropriate only for laboratory-scale and battlefield-scale trajectories, and noting on theoretical grounds that the parabola could not possibly apply to a trajectory so large as to be comparable to the size of the planet.[13] Thirdly, Galilei recognized that his experimental data would never agree exactly with any theoretical or mathematical form, because of the imprecision of measurement, irreducible friction, and other factors. Wikibooks has more on the topic of Conic section Types of conic sections Table of conics, Cyclopaedia, 1728 In mathematics, a conic section (or just conic) is a curve that can be formed by intersecting a cone (more precisely, a right circular conical surface) with a plane. ...

According to Stephen Hawking, Galileo probably bears more of the responsibility for the birth of modern science than anybody else,[14] and Albert Einstein called him the father of modern science.[15] Stephen William Hawking, CH, CBE, FRS, FRSA, (born 8 January 1942) is a British theoretical physicist. ... â€œEinsteinâ€ redirects here. ...

## Astronomy

### Contributions

Based only on sketchy descriptions of the telescope, invented in the Netherlands in 1608, during that same year Galileo made a telescope with about 3x magnification, and later made others with up to about 32x magnification. With this improved device he could see magnified, upright images on the earth - it was what is now known as a terrestrial telescope, or spyglass. He could also use it to observe the sky; for a time he was one of very few who could construct telescopes good enough for that purpose. On 25 August 1609, he demonstrated his first telescope to Venetian lawmakers. His work on the device made for a profitable sideline with merchants who found it useful for their shipping businesses and trading issues. He published his initial telescopic astronomical observations in March 1610 in a short treatise entitled Sidereus Nuncius (Starry Messenger). is the 237th day of the year (238th in leap years) in the Gregorian calendar. ... // Events April 4 â€“ King of Spain signs an edit of expulsion of all moriscos from Spain April 9 â€“ Spain recognizes Dutch independence May 23 - Official ratification of the Second Charter of Virginia. ... For other uses, see Venice (disambiguation). ... Sidereus Nuncius (usually translated into English as Sidereal Messenger, although Starry Messenger and Sidereal Message are also seen) is a short treatise published in Latin by Galileo Galilei in March 1610. ...

It was on this page that Galileo first noted an observation of the moons of Jupiter. This observation upset the notion that all celestial bodies must revolve around the Earth. Galileo published a full description in Sidereus Nuncius in March 1610

Galileo also observed the planet Saturn, and at first mistook its rings for planets, thinking it was a three-bodied system. When he observed the planet later, Saturn's rings were directly oriented at Earth, causing him to think that two of the bodies had disappeared. The rings reappeared when he observed the planet in 1616, further confusing him.[16] Atmospheric characteristics Atmospheric pressure 140 kPa Hydrogen >93% Helium >5% Methane 0. ...

Galileo was one of the first Europeans to observe sunspots. He also reinterpreted a sunspot observation from the time of Charlemagne, which formerly had been attributed (impossibly) to a transit of Mercury. The very existence of sunspots showed another difficulty with the unchanging perfection of the heavens as assumed in the older philosophy. And the annual variations in their motions, first noticed by Francesco Sizzi, presented great difficulties for both the geocentric system and that of Tycho Brahe. A dispute over priority in the discovery of sunspots, and in their interpretation, led Galileo to a long and bitter feud with the Jesuit Christoph Scheiner; in fact, there is little doubt that both of them were beaten by David Fabricius and his son Johannes. Scheiner quickly adopted Kepler's 1615 proposal of the modern telescope design, which gave larger magnification at the cost of inverted images; Galileo apparently never changed to Kepler's design. For other uses, see Sunspot (disambiguation). ... Charlemagne (left) and Pippin the Hunchback. ... This article is about the planet. ... Monument of Tycho Brahe and Johannes Kepler in Prague Tycho Brahe, born Tyge Ottesen Brahe (December 14, 1546 â€“ October 24, 1601), was a Danish nobleman from the region of Scania (in modern-day Sweden), best known today as an early astronomer, though in his lifetime he was also well known... Christoph Scheiner (July 25, 1573 or 1575 â€“ June 18, 1650) was a German astronomer and Jesuit. ... David and Johannes Fabricius were father and son astronomers from Frisia. ... David and Johannes Fabricius were father and son astronomers from Frisia. ...

Galileo was the first to report lunar mountains and craters, whose existence he deduced from the patterns of light and shadow on the Moon's surface. He even estimated the mountains' heights from these observations. This led him to the conclusion that the Moon was "rough and uneven, and just like the surface of the Earth itself," rather than a perfect sphere as Aristotle had claimed. Galileo observed the Milky Way, previously believed to be nebulous, and found it to be a multitude of stars packed so densely that they appeared to be clouds from Earth. He located many other stars too distant to be visible with the naked eye. Galileo also observed the planet Neptune in 1612, but did not realize that it was a planet and took no particular notice of it. It appears in his notebooks as one of many unremarkable dim stars. For other uses, see Mountain (disambiguation). ... Tycho crater on Earths moon. ... A sphere is a symmetrical geometrical object. ... For other uses, see Milky Way (disambiguation). ... The Triangulum Emission Nebula NGC 604 The Pillars of Creation from the Eagle Nebula For other uses, see Nebula (disambiguation). ... STAR is an acronym for: Organizations Society of Ticket Agents and Retailers], the self-regulatory body for the entertainment ticket industry in the UK. Society for Telescopy, Astronomy, and Radio, a non-profit New Jersey astronomy club. ... Atmospheric characteristics Surface pressure â‰«100 MPa Hydrogen - H2 80% Â±3. ...

## Technology

Galileo Galilei. Portrait in crayon by Leoni
A replica of the earliest surviving telescope attributed to Galileo Galilei, on display at the Griffith Observatory

In 1612, having determined the orbital periods of Jupiter's satellites, Galileo proposed that with sufficiently accurate knowledge of their orbits one could use their positions as a universal clock, and this would make possible the determination of longitude. He worked on this problem from time to time during the remainder of his life; but the practical problems were severe. The method was first successfully applied by Giovanni Domenico Cassini in 1681 and was later used extensively for large land surveys; this method, for example, was used by Lewis and Clark. For sea navigation, where delicate telescopic observations were more difficult, the longitude problem eventually required development of a practical portable marine chronometer, such as that of John Harrison. Longitude is the east-west geographic coordinate measurement most commonly utilized in cartography and global navigation. ... Giovanni Domenico (Jean-Dominique) Cassini Portrait Giovanni Domenico Cassini (June 8, 1625â€“September 14, 1712) was an Italian astronomer, engineer, and astrologer. ... The Lewis and Clark expedition (1804-1806) was the first American overland expedition to the Pacific coast and back. ... A marine chronometer is a timekeeper precise enough to be used as a portable time standard, used to determine longitude by means of celestial navigation. ... John Harrison John Harrison (March 24, 1693â€“March 24, 1776) was an English clockmaker, who designed and built the worlds first successful chronometer (maritime clock), one whose accuracy was great enough to allow the determination of longitude over long distances. ...

In his last year, when totally blind, he designed an escapement mechanism for a pendulum clock, a vectorial model of which may be seen here. The first fully operational pendulum clock was made by Christiaan Huygens in the 1650s. Galilei created sketches of various inventions, such as a candle and mirror combination to reflect light throughout a building, an automatic tomato picker, a pocket comb that doubled as an eating utensil, and what appears to be a ballpoint pen. A simple escapement. ... There are very few or no other articles that link to this one. ... Christiaan Huygens (pronounced in English (IPA): ; in Dutch: ) (April 14, 1629 â€“ July 8, 1698), was a Dutch mathematician, astronomer and physicist; born in The Hague as the son of Constantijn Huygens. ...

### Controversy over comets and The Assayer

Main article: The Assayer

In 1619 Galileo became embroiled in a controversy with Father Horatio Grassi, the professor of mathematics at the Jesuit Collegio Romano. It began as a dispute over the nature of comets, but by the time Galileo had published The Assayer (Il Saggiatore) in 1623, his last salvo in the dispute, it had become a much wider argument over the very nature of Science itself. Because The Assayer contains such a wealth of Galileo's ideas on how Science should be practised, it has been referred to as his scientific manifesto.[23] In 1616 Galileo[1] may have been silenced on Copernicanism, but he bounced back with gusto in 1623. ... In 1616 Galileo[1] may have been silenced on Copernicanism, but he bounced back with gusto in 1623. ... The North American College at the Gregorian The Pontifical Gregorian University is a Roman Catholic theological seminary in Rome. ...

Early in 1619 Father Grassi had anonymously published a pamphlet, An Astronomical Disputation on the Three Comets of the Year 1618,[24] which discussed the nature of a comet that had appeared late in November of the previous year. Grassi concluded that the comet was a fiery body which had moved along a segment of a great circle at a constant distance from the earth,[25] and that it had been located well beyond the moon. In 1616 Galileo[1] may have been silenced on Copernicanism, but he bounced back with gusto in 1623. ...

Grassi's arguments and conclusions were criticised in a subsequent article, Discourse on the Comets,[26] published under the name of one of Galileo's disciples, a Florentine lawyer named Mario Guiducci, although it had been largely written by Galileo himself.[27] Galileo and Guiducci offered no definitive theory of their own on the nature of comets, [28] although they did present some tentative conjectures which we now know to be mistaken. In 1616 Galileo[1] may have been silenced on Copernicanism, but he bounced back with gusto in 1623. ...

In its opening passage, Galileo and Guiducci's Discourse gratuitously insulted the Jesuit Christopher Scheiner, [29] and various uncomplimentary remarks about the professors of the Collegio Romano were scattered throughout the work.[30] The Jesuits were offended,[31] and Grassi soon replied with a polemical tract of his own, The Astronomical and Philosophical Balance,[32] under the pseudonym Lothario Sarsi, purporting to be one of his own pupils. Christoph Scheiner (July 25, 1573 or 1575 &#8211; June 18, 1650) was a German astronomer and Jesuit. ... In 1616 Galileo[1] may have been silenced on Copernicanism, but he bounced back with gusto in 1623. ...

The Assayer,[33] was Galileo's devastating reply to the Astronomical Balance. It has been widely regarded as a masterpiece of polemical literature,[34] in which "Sarsi's" arguments are subjected to withering scorn.[35] It was greeted with wide acclaim, and particularly pleased the new pope, Urban VIII, to whom it had been dedicated.[36] Urban VIII, né Maffeo Barberini (April 1568 - July 29, 1644) was pope from 1623-1644. ...

Galileo's dispute with Grassi permanently alienated many of the Jesuits who had previously been sympathetic to his ideas,[37] and Galileo and his friends were convinced that these Jesuits were responsible for bringing about his later condemnation.[38] The evidence for this is at best equivocal, however.[39]

### Galileo, Kepler and theories of tides

Cardinal Bellarmine had written in 1615 that the Copernican system could not be defended without "a true [physical] demonstration that the sun does not circle the earth but the earth circles the sun".[40] Galileo considered his theory of the tides to provide the required physical proof of the motion of the earth. This theory was so important to Galileo that he originally intended to entitle his Dialogue on the Two Chief World Systems the Dialogue on the Ebb and Flow of the Sea.[41] For Galileo, the tides were caused by the sloshing back and forth of water in the seas as a point on the Earth's surface speeded up and slowed down because of the Earth's rotation on its axis and revolution around the Sun. Galileo circulated his first account of the tides in 1616, addressed to Cardinal Orsini.[42] This article is about tides in the Earths oceans. ...

If this theory were correct, there would be only one high tide per day. Galileo and his contemporaries were aware of this inadequacy because there are two daily high tides at Venice instead of one, about twelve hours apart. Galileo dismissed this anomaly as the result of several secondary causes, including the shape of the sea, its depth, and other factors.[43] Against the assertion that Galileo was deceptive in making these arguments, Albert Einstein expressed the opinion that Galileo developed his "fascinating arguments" and accepted them uncritically out of a desire for physical proof of the motion of the Earth.[44] For other uses, see Venice (disambiguation). ... â€œEinsteinâ€ redirects here. ...

Galileo dismissed as a "useless fiction" the idea, held by his contemporary Johannes Kepler, that the moon caused the tides.[45] Galileo also refused to accept Kepler's elliptical orbits of the planets,[46] considering the circle the "perfect" shape for planetary orbits. Johannes Kepler (December 27, 1571 â€“ November 15, 1630) was a German mathematician, astronomer and astrologer, and a key figure in the 17th century astronomical revolution. ... Johannes Kepler (December 27, 1571 â€“ November 15, 1630) was a German mathematician, astronomer and astrologer, and a key figure in the 17th century astronomical revolution. ...

## Physics

Galileo's theoretical and experimental work on the motions of bodies, along with the largely independent work of Kepler and René Descartes, was a precursor of the classical mechanics developed by Sir Isaac Newton. He was a pioneer, at least in the European tradition, in performing rigorous experiments and insisting on a mathematical description of the laws of nature. â€œDescartesâ€ redirects here. ... Classical mechanics (commonly confused with Newtonian mechanics, which is a subfield thereof) is used for describing the motion of macroscopic objects, from projectiles to parts of machinery, as well as astronomical objects, such as spacecraft, planets, stars, and galaxies. ... Sir Isaac Newton FRS (4 January 1643 â€“ 31 March 1727) [ OS: 25 December 1642 â€“ 20 March 1727][1] was an English physicist, mathematician, astronomer, natural philosopher, and alchemist. ... Euclid, Greek mathematician, 3rd century BC, as imagined by by Raphael in this detail from The School of Athens. ...

Galileo is said to have dropped balls of different masses from the Leaning Tower of Pisa to demonstrate that their time of descent was independent of their mass (excluding the limited effect of air resistance). This was contrary to what Aristotle had taught: that heavy objects fall faster than lighter ones, in direct proportion to weight. Although the story of the tower first appeared in a biography by Galileo's pupil Vincenzo Viviani, it is not now generally accepted as true. Moreover, Giambattista Benedetti had reached the same scientific conclusion years before, in 1553. However, Galileo did perform experiments involving rolling balls down inclined planes, one of which is in Florence, called the bell and ball experiment, which proved the same thing: falling or rolling objects (rolling is a slower version of falling, as long as the distribution of mass in the objects is the same) are accelerated independently of their mass. Galileo was the first person to demonstrate this via experiment, but he was not—contrary to popular belief—the first to argue that it was true. John Philoponus had argued this centuries earlier. For other uses, see Ball (disambiguation). ... This article or section is in need of attention from an expert on the subject. ... The Leaning Tower of Pisa (Italian: ) or simply The Tower of Pisa (La Torre di Pisa) is the campanile, or freestanding bell tower, of the cathedral of the Italian city of Pisa. ... Vincenzo Viviani. ... Giambattista (Gianbattista) Benedetti (1530â€“1590) was a Venetian mathematician who wrote La gnomonica. ... In the scientific method, an experiment (Latin: ex- periri, of (or from) trying) is a set of observations performed in the context of solving a particular problem or question, to support or falsify a hypothesis or research concerning phenomena. ... The inclined plane is one of the classical simple machines; as the name suggests, it is a flat surface whose endpoints are at different heights. ... Acceleration is the time rate of change of velocity and/or direction, and at any point on a velocity-time graph, it is given by the slope of the tangent to the curve at that point. ... It has been suggested that this article or section be merged with Joannes Philoponus. ... The Oxford Calculators were a group of 14th-century thinkers, almost all associated with Merton College, Oxford, who took a strikingly logico-mathematical approach to philosophical problems. ...

Galileo determined the correct mathematical law for acceleration: the total distance covered, starting from rest, is proportional to the square of the time ($d propto t^2$). He expressed this law using geometrical constructions and mathematically-precise words, adhering to the standards of the day. (It remained for others to re-express the law in algebraic terms). He also concluded that objects retain their velocity unless a force—often friction—acts upon them, refuting the generally accepted Aristotelian hypothesis that objects "naturally" slow down and stop unless a force acts upon them (again this was not a new idea: Ibn al-Haytham had proposed it centuries earlier, as had Jean Buridan, and according to Joseph Needham, Mo Tzu had proposed it centuries before either of them, but this was the first time that it had been mathematically expressed). Galileo's Principle of Inertia stated: "A body moving on a level surface will continue in the same direction at constant speed unless disturbed." This principle was incorporated into Newton's laws of motion (first law). its made by jaypeeng magandang google wikepedia For other uses, see Force (disambiguation). ... For other uses, see Friction (disambiguation). ... (Arabic: Ø£Ø¨Ùˆ Ø¹Ù„ÙŠ Ø§Ù„Ø­Ø³Ù† Ø¨Ù† Ø§Ù„Ø­Ø³Ù† Ø¨Ù† Ø§Ù„Ù‡ÙŠØ«Ù…, Latinized: Alhacen or (deprecated) Alhazen) (965 â€“ 1039), was an Arab[1] Muslim polymath[2][3] who made significant contributions to the principles of optics, as well as to anatomy, astronomy, engineering, mathematics, medicine, ophthalmology, philosophy, physics, psychology, visual perception, and to science in general with his introduction of the... Jean Buridan, in Latin Joannes Buridanus (1300 - 1358) was a French priest who sowed the seeds of religious scepticism in Europe. ... Joseph Terence Montgomery Needham (December 9, 1900 â€“ March 24, 1995) was a British biochemist and pre-eminent authority on the history of Chinese science. ... Mozi (c. ... Newtons First and Second laws, in Latin, from the original 1687 edition of the Principia Mathematica. ...

Dome of the cathedral of Pisa with the "lamp of Galileo"

In 1638 Galileo described an experimental method to measure the speed of light by arranging that two observers, each having lanterns equipped with shutters, observe each other's lanterns at some distance. The first observer opens the shutter of his lamp, and, the second, upon seeing the light, immediately opens the shutter of his own lantern. The time between the first observer's opening his shutter and seeing the light from the second observer's lamp indicates the time it takes light to travel back and forth between the two observers. Galileo reported that when he tried this at a distance of less than a mile, he was unable to determine whether or not the light appeared instantaneously.[47] Sometime between Galileo's death and 1667, the members of the Florentine Accademia del Cimento repeated the experiment over a distance of about a mile and obtained a similarly inconclusive result.[48] The Accademia del Cimento (Academy of Experiment), a early scientific society, was founded in Florence 1657 by students of Galileo, Evangelista Torricelli and Vincenzo Viviani. ...

Galileo is lesser known for, yet still credited with, being one of the first to understand sound frequency. By scraping a chisel at different speeds, he linked the pitch of the sound produced to the spacing of the chisel's skips, a measure of frequency.

In his 1632 Dialogue Galileo presented a physical theory to account for tides, based on the motion of the Earth. If correct, this would have been a strong argument for the reality of the Earth's motion. In fact, the original title for the book described it as a dialogue on the tides; the reference to tides was removed by order of the Inquisition. His theory gave the first insight into the importance of the shapes of ocean basins in the size and timing of tides; he correctly accounted, for instance, for the negligible tides halfway along the Adriatic Sea compared to those at the ends. As a general account of the cause of tides, however, his theory was a failure. Kepler and others correctly associated the Moon with an influence over the tides, based on empirical data; a proper physical theory of the tides, however, was not available until Newton. Frontispiece and title page of the Dialogue The Dialogue Concerning the Two Chief World Systems (Dialogo sopra i due massimi sistemi del mondo) was a 1632 book by Galileo, comparing the Copernican system, and the traditional Ptolemaic system. ... This article is about tides in the Earths oceans. ... A satellite image of the Adriatic Sea. ...

Galileo also put forward the basic principle of relativity, that the laws of physics are the same in any system that is moving at a constant speed in a straight line, regardless of its particular speed or direction. Hence, there is no absolute motion or absolute rest. This principle provided the basic framework for Newton's laws of motion and is central to Einstein's special theory of relativity. Galilean invariance is a principle which states that the fundamental laws of physics are the same in all inertial (uniform-velocity) frames of reference. ... â€œEinsteinâ€ redirects here. ... Special relativity (SR) or the special theory of relativity is the physical theory published in 1905 by Albert Einstein. ...

## Mathematics

While Galileo's application of mathematics to experimental physics was innovative, his mathematical methods were the standard ones of the day. The analysis and proofs relied heavily on the Eudoxian theory of proportion, as set forth in the fifth book of Euclid's Elements. This theory had become available only a century before, thanks to accurate translations by Tartaglia and others; but by the end of Galileo's life it was being superseded by the algebraic methods of Descartes. Another article concerns Eudoxus of Cyzicus. ... The frontispiece of Sir Henry Billingsleys first English version of Euclids Elements, 1570 Euclids Elements (Greek: ) is a mathematical and geometric treatise, consisting of 13 books, written by the Hellenistic mathematician Euclid in Alexandria circa 300 BC. It comprises a collection of definitions, postulates (axioms), propositions (theorems... NiccolÃ² Fontana Tartaglia. ... â€œDescartesâ€ redirects here. ...

Galileo produced one piece of original and even prophetic work in mathematics: Galileo's paradox, which shows that there are as many perfect squares as there are whole numbers, even though most numbers are not perfect squares. Such seeming contradictions were brought under control 250 years later in the work of Georg Cantor. Galileos paradox is a demonstration of one of the surprising properties of infinite sets. ... Georg Ferdinand Ludwig Philipp Cantor (March 3, 1845[1] â€“ January 6, 1918) was a German mathematician. ...

## Church controversy

Main article: Galileo affair
Cristiano Banti's 1857 painting Galileo facing the Roman Inquisition

Western Christian biblical references "Psalm 93:1", "Psalm 96:10", and "Chronicles 16:30" include text stating that "the world is firmly established, it cannot be moved." In the same tradition, "Psalm 104:5" says, "[the LORD] set the earth on its foundations; it can never be moved." Further, "Ecclesiastes 1:5" states that "the sun rises and the sun sets, and hurries back to where it rises." Galileo before the Holy Office, a 19th century painting by Joseph-Nicolas Robert-Fleury The Galileo affair, in which Galileo Galilei came into conflict with the Catholic Church over his support of Copernican astronomy, is often considered a defining moment in the history of the relationship between religion and science. ... Image File history File links Galileo_facing_the_Roman_Inquisition. ... Image File history File links Galileo_facing_the_Roman_Inquisition. ...

Galileo defended heliocentrism, and claimed it was not contrary to those Scripture passages. He took Augustine's position on Scripture: not to take every passage literally, particularly when the scripture in question is a book of poetry and songs, not a book of instructions or history. The writers of the Scripture wrote from the perspective of the terrestrial world, and from that vantage point the sun does rise and set. In fact, it is the earth's rotation which gives the impression of the sun in motion across the sky. Heliocentric Solar System Heliocentrism (lower panel) in comparison to the geocentric model (upper panel) In astronomy, heliocentrism is the theory that the sun is at the centre of the Universe and/or the Solar System. ... â€œAugustinusâ€ redirects here. ...

Pope Urban VIII personally asked Galileo to give arguments for and against heliocentrism in the book, and to be careful not to advocate heliocentrism. He made another request, that his own views on the matter be included in Galileo's book. Only the latter of those requests was fulfilled by Galileo. Whether unknowingly or deliberate, Simplicius, the defender of the Aristotelian Geocentric view in Dialogue Concerning the Two Chief World Systems, was often caught in his own errors and sometimes came across as a fool. This fact made Dialogue Concerning the Two Chief World Systems appear as an advocacy book; an attack on Aristotelian geocentrism and defense of the Copernican theory. To add insult to injury, Galileo put the words of Pope Urban VIII into the mouth of Simplicius. Most historians agree Galileo did not act out of malice and felt blindsided by the reaction to his book. However, the Pope did not take the public ridicule lightly, nor the blatant bias. Galileo had alienated one of his biggest and most powerful supporters, the Pope, and was called to Rome to defend his writings.

With the loss of many of his defenders

` in Rome because of Dialogue Concerning the Two Chief World Systems, Galileo was ordered to stand trial on suspicion of heresy in 1633. The sentence of the Inquisition was in three essential parts: `
• Galileo was required to recant his heliocentric ideas; the idea that the Sun is stationary was condemned as "formally heretical." However, while there is no doubt that Pope Urban VIII and the vast majority of Church officials did not believe in heliocentrism, heliocentrism was never formally or officially condemned by the Catholic Church, except insofar as it held (for instance, in the formal condemnation of Galileo) that "The proposition that the sun is in the center of the world and immovable from its place is absurd, philosophically false, and formally heretical; because it is expressly contrary to Holy Scriptures", and the converse as to the Sun's not revolving around the Earth.[49]
• He was ordered imprisoned; the sentence was later commuted to house arrest.
• His offending Dialogue was banned; and in an action not announced at the trial, publication of any of his works was forbidden, including any he might write in the future.[50]
Tomb of Galileo Galilei, Santa Croce

Galileo died on January 8, 1642, and was buried the next day in his family grave in the Santa Croce basilica of Firenze. He was reburied on sacred ground after a monument was erected in his honor at Santa Croce in 1737. He was formally rehabilitated in 1741, when Pope Benedict XIV authorized the publication of Galileo's complete scientific works (a censored edition had been published in 1718), and in 1758 the general prohibition against heliocentrism was removed from the Index Librorum Prohibitorum. On 31 October 1992, Pope John Paul II expressed regret for how the Galileo affair was handled, as the result of a study conducted by the Pontifical Council for Culture.[51] FaÃ§ade. ... In various religions, sacred (from Latin, sacrum, sacrifice) or holy, objects, places or concepts are believed by followers to be intimately connected with the supernatural, or divinity, and are thus greatly revered. ... FaÃ§ade. ... Benedict XIV, born Prospero Lorenzo Lambertini (Bologna, March 31, 1675 â€“ May 3, 1758 in Rome), was Pope from 17 August 1740 to 3 May 1758. ... Venetiis, M. D. LXIIII. The Index Librorum Prohibitorum (List of Prohibited Books) is a list of publications which the Catholic Church censored for being a danger to itself and the faith of its members. ... is the 304th day of the year (305th in leap years) in the Gregorian calendar. ... Year 1992 (MCMXCII) was a leap year starting on Wednesday (link will display full 1992 Gregorian calendar). ... Coat of Arms of Pope John Paul II. The Letter M is for Mary, the mother of Jesus, to whom he held strong devotion Pope John Paul II (Latin: , Italian: Giovanni Paolo II, Polish: Jan PaweÅ‚ II) born   []; 18 May 1920 â€“ 2 April 2005) reigned as the 264th Pope of... The Pontifical Council for Culture (Pontificium Consilium de Cultura) dates back to the Second Vatican Council. ...

## Galileo's writings

Statue outside the Uffizi, Florence

## Notes

1. ^ a b c d e J J O'Connor and E F Robertson. Galileo Galilei. The MacTutor History of Mathematics archive. University of St Andrews, Scotland. Retrieved on 2007-07-24.
2. ^ "Galileo Galilei" in the 1913 Catholic Encyclopedia. by John Gerard. Retrieved 11 August 2007
3. ^ Singer, Charles (1941), A Short History of Science to the Nineteenth Century, Clarendon Press, <http://www.google.com.au/books?id=mPIgAAAAMAAJ&pgis=1> (page 217)
4. ^ a b Weidhorn, Manfred (2005). The Person of the Millennium: The Unique Impact of Galileo on World History. iUniverse, p. 155. ISBN 0595368778.
5. ^ Maurice A. Finocchiaro, “Review of The Person of the Millennium: The Unique Impact of Galileo on World History,” The Historian 69.3 (Fall, 2007): 602.
6. ^ Sharratt (1996, pp.127-131), McMullin (2005a).
7. ^ H. Darrel Rutkin. Galileo, Astrology, and the Scientific Revolution: Another Look. Program in History & Philosophy of Science & Technology, Stanford University. Retrieved on 2007-04-15.
8. ^ Sobel (2000, p.5). Chapter 1. Retrieved on August 26, 2007. "But because he never married Virginia's mother, he deemed the girl herself unmarriageable. Soon after her thirteenth birthday, he placed her at the Convent of San Matteo in Arcetri."
9. ^ There are contradictory documents describing the nature of this admonition and the circumstances of its delivery. Finocchiaro, The Galileo Affair, pp.147–149, 153
10. ^ In Drake (1957, pp.237−238)
11. ^ Wallace, (1984)
12. ^ Paul Feyerabend, Against Method (third edition, London: Verso, 1993), p. 129.
13. ^ Galilei (1954, p.250); Favaro (1898, 8:274) (Italian).
14. ^ Hawking (1988, p.179).
15. ^ Einstein (1954, p.271). "Propositions arrived at by purely logical means are completely empty as regards reality. Because Galileo realised this, and particularly because he drummed it into the scientific world, he is the father of modern physics—indeed, of modern science altogether."
16. ^ Baalke, Ron. Historical Background of Saturn's Rings. Jet Propulsion Laboratory, California Institute of Technology, NASA. Retrieved on 2007-03-11
17. ^ Drake (1978, p.163-164), Favaro (1892, 3:163-164)(Latin).
18. ^ Probably in 1623, according to Drake (1978, p.286).
19. ^ Drake (1978, p.289), Favaro (1903, 13:177) (Italian).
20. ^ Drake (1978, p.286), Favaro (1903, 13:208)(Italian). The inventors of the telescope and microscope remain debatable. A general view on this can be found in Hans Lippershey (last updated 2003-08-01), © 1995-2007 by Davidson, Michael W. and the Florida State University. Retrieved 2007-08-28
21. ^ Van Helden, Al. Galileo Timeline (last updated 1995), The Galileo Project. Retrieved 2007-08-28. See also Timeline of microscope technology.
22. ^ Drake (1978, p.286).
23. ^ Drake (1960, pp.vii,xxiii-xxiv), Sharratt (1996, pp.139-140).
24. ^ Grassi (1960a).
25. ^ Drake (1978, p.268), Grassi (1960a, p.16).
26. ^ Galilei & Guiducci (1960).
27. ^ Drake (1960, p.xvi).
28. ^ Drake (1957, p.222), Drake (1960, p.xvii).
29. ^ Sharratt (1996, p.135), Drake (1960, p.xii), Galilei & Guiducci (1960, p.24).
30. ^ Sharratt (1996, p.135).
31. ^ Sharratt (1996, p.135), Drake (1960, p.xvii).
32. ^ Grassi (1960b).
33. ^ Galilei (1960).
34. ^ Sharratt (1996, p.137), Drake (1957, p.227).
35. ^ Sharratt (1996, p.138-142).
36. ^ Drake (1960, p.xix).
37. ^ Drake (1960, p.vii).
38. ^ Sharratt (1996, p.175).
39. ^ Sharratt (1996, pp.175-178).
40. ^ Finocchiaro (1989), pp. 67–9.
41. ^ Finocchiaro (1989), p. 354, n. 52
42. ^ Finocchiaro (1989), pp.119–133
43. ^ Finocchiaro (1989), pp.127–131 and Drake (1953), pp. 432–6
44. ^ Einstein (1952) p. xvii
45. ^ Finocchiaro (1989), p. 128
46. ^ Sachiko Kusukawa. Starry Messenger. The Telescope, Department of History and Philosophy of Science of the University of Cambridge. Retrieved on 2007-03-10
47. ^ Galileo Galilei, Two New Sciences, (Madison: Univ. of Wisconsin Pr., 1974) p. 50.
48. ^ I. Bernard Cohen, "Roemer and the First Determination of the Velocity of Light (1676)," Isis, 31 (1940): 327–379, see pp. 332–333
49. ^ The Crime of Galileo: Indictment and Abjuration of 1633. Modern History Sourcebook. Retrieved on 2007-07-24.
50. ^ Drake (1978, p.367), Sharratt (1996, p.184), Favaro (1905, 16:209, 230)(Italian). See Galileo affair for further details.
51. ^ Vatican admits Galileo was right. New Scientist 07 November 1992. Retrieved on 09 August 2007.

## References

• Allan-Olney, Mary. The private Life of Galileo: Compiled primarily from his correspondence and that of his eldest daughter, Sister Maria Celeste, (nun in the Franciscan convent of St. Matthew, in Arcetri), 1870, Boston : Nichols and Noyes. - Google Books: The private Life of Galileo - The Internet Archive
• Biagioli, Mario (1993). Galileo, Courtier: The Practice of Science in the Culture of Absolutism. Chicago: University of Chicago Press.
• Consolmagno, Guy; Schaefer, Marta (1994). Worlds Apart, A Textbook in Planetary Science. Englewood, New Jersey: Prentice-Hall, Inc. ISBN 0-13-964131-9
• Drake, Stillman (1953), trans. Dialogue Concerning the Two Chief World Systems. Berkeley: University of California Press.
• Drake, Stillman (1957). Discoveries and Opinions of Galileo. New York: Doubleday & Company. ISBN 0-385-09239-3
• Drake, Stillman (1960). Introduction to the Controversy on the Comets of 1618, In Drake & O'Malley (1960, pp.vii–xxv).
• Drake, Stillman (1973). "Galileo's Discovery of the Law of Free Fall". Scientific American v. 228, #5, pp. 84–92.
• Drake, Stillman (1978). Galileo At Work. Chicago: University of Chicago Press. ISBN 0-226-16226-5
• Drake, Stillman, and O'Malley, C.D. (translators) (1960). The Controversy on the Comets of 1618. Philadelphia, PA: University of Philadelphia Press.
• Einstein, Albert (1952). Foreword to (Drake, 1953)
• Einstein, Albert (1954). Ideas and Opinions, translated by Sonja Bargmann, London: Crown Publishers. ISBN 0-285-64724-5.
• Fantoli, Annibale (2003). Galileo — For Copernicanism and the Church, third English edition. Vatican Observatory Publications. ISBN 88-209-7427-4
• Favaro, Antonio (1890–1909), ed.[1]. Le Opere di Galileo Galilei, Edizione Nazionale (Italian). (The Works of Galileo Galilei, National Edition, 20 vols.), Florence: Barbera, 1890–1909; reprinted 1929–1939 and 1964–1966. ISBN 88-09-20881-1. Searchable online copy from the Institute and Museum of the History of Science, Florence . Brief overview of "Le Opere" @ Finns Fine Books, [2] and here [3]
• Fillmore, Charles (1931, 17th printing July 2004). Metaphysical Bible Dictionary. Unity Village, Missouri: Unity House. ISBN 0-87159-067-0
• Finocchiaro, Maurice A. (1989). The Galileo Affair: A Documentary History. Berkeley: University of California Press. ISBN 0-520-06662-6
• Galilei, Galileo [1623] (1960). The Assayer, translated by Stillman Drake. In Drake & O'Malley (1960, pp.151–336).
• Galilei, Galileo [1638,1914] (1954), Henry Crew and Alfonso de Salvio, translators, Dialogues Concerning Two New Sciences, Dover Publications Inc., New York, NY. ISBN 486-60099-8
• Galilei, Galileo, and Guiducci, Mario [1619] (1960). Discourse on the Coments, translated by Stillman Drake. In Drake & O'Malley (1960, pp.21–65).
• Gebler, Karl von. Galileo Galilei and the Roman Curia : from authentic sources, London, C.K. Paul & co., 1879; Merrick, N.Y. : Richwood Pub. Co., 1977. - Google Books ISBN 0-915172-11-9
• Geymonat, Ludovico (1965), Galileo Galilei, A biography and inquiry into his philosophy and science, translation of the 1957 Italian edition, with notes and appendix by Stillman Drake, McGraw-Hill
• Grassi, Horatio [1619] (1960a). On the Three Comets of the Year MDCXIII, translated by C.D. O'Malley. In Drake & O'Malley (1960, pp.3–19).
• Grassi, Horatio [1619] (1960b). The Astronomical and Philosophical Balance, translated by C.D. O'Malley. In Drake & O'Malley (1960, pp.67–132).
• Grisar, Hartmann, S.J., Professor of Church history at the University of Innsbruck (1882). Historisch theologische Untersuchungen über die Urtheile Römischen Congegationen im Galileiprocess (Historico-theological Discussions concerning the Decisions of the Roman Congregations in the case of Galileo), Regensburg: Pustet. - Google Books ISBN 0-7905-6229-4. (LCC # QB36 - microfiche) Reviewed here (1883), pp.211–213
• Hawking, Stephen (1988). A Brief History of Time. New York, NY: Bantam Books. ISBN 0-553-34614-8.
• Hellman, Hal (1988). Great Feuds in Science. Ten of the Liveliest Disputes Ever. New York: Wiley
• Kelter, Irving A. (2005). The Refusal to Accommodate. Jesuit Exegetes and the Copernican System, In McMullin (2005, pp.38–53).
• Koestler, Arthur. The Sleepwalkers: A History of Man's Changing Vision of the Universe 1958, Penguin (Non-Classics); Reprint edition (June 5, 1990). ISBN 0-14-019246-8
• Lattis, James M. (1994). Between Copernicus and Galileo: Christopher Clavius and the Collapse of Ptolemaic Cosmology, Chicago: the University of Chicago Press
• Langford, Jerome, Galileo, Science and the Church, third edition, St. Augustine's Press, 1998. ISBN 1-890318-25-6
• Lessl, Thomas, "The Galileo Legend". New Oxford Review, 27–33 (June 2000).
• McMullin, Ernan, ed. (2005). The Church and Galileo. Notre Dame, IN: University of Notre Dame Press. ISBN 0-268-03483-4.
• McMullin, Ernan, (2005a). The Church's Ban on Copernicanism, 1616, In McMullin (2005, pp.150–190).
• Naylor, Ronald H. (1990). "Galileo's Method of Analysis and Synthesis," Isis, 81: 695–707
• Newall, Paul (2004). "The Galileo Affair"
• Remmert, Volker R. (2005). Galileo, God, and Mathematics. In: Bergmans, Luc/Koetsier, Teun (eds.): Mathematics and the Divine. A Historical Study, Amsterdam et al., 347–360
• Settle, Thomas B. (1961). "An Experiment in the History of Science". Science, 133:19–23
• Sharratt, Michael (1996), Galileo: Decisive Innovator. Cambridge University Press, Cambridge. ISBN 0-521-56671-1
• Sobel, Dava [1999] 2000. Galileo's Daughter. Fourth Estate, London. ISBN 1-85702-712-4
• Wallace, William A. (1984) Galileo and His Sources: The Heritage of the Collegio Romano in Galileo's Science, (Princeton: Princeton Univ. Pr.), ISBN 0-691-08355-X
• White, Andrew Dickson (1898). A History of the Warfare of Science with Theology in Christendom. New York 1898.
• White, Michael. (2007). Galileo: Antichrist: A Biography. Weidenfeld & Nicolson:London, ISBN 978-0-297-84868-4.
• Wisan, Winifred Lovell (1984). "Galileo and the Process of Scientific Creation," Isis, 75: 269–286.
• Zik Yaakov, "Science and Instruments: The telescope as a scientific instrument at the beginning of the seventeenth century", Perspectives on Science 2001, Vol. 9, 3, 259–284.

// Google offers a variety of services and tools besides its basic web search. ... Internet Archive headquarters. ... â€œEinsteinâ€ redirects here. ... This article is about the city in Italy. ... // Google offers a variety of services and tools besides its basic web search. ... // Google offers a variety of services and tools besides its basic web search. ... Stephen William Hawking, CH, CBE, FRS, FRSA, (born 8 January 1942) is a British theoretical physicist. ... Arthur Koestler (September 5, 1905, Budapest â€“ March 3, 1983, London) was a Hungarian polymath who became a naturalized British subject. ...

Results from FactBites:

 Galileo Galilei (2434 words) Galileo Galilei was an Italian natural philosopher, astronomer, and mathematician who made fundamental contributions to the sciences of motion, astronomy, and strength of materials and to the development of the scientific method. Galileo was born in Pisa, Tuscany, on February 15, 1564, the oldest son of Vincenzo Galilei, a musician who made important contributions to the theory and practice of music and who may have performed some experiments with Galileo in 1588-89 on the relationship between pitch and the tension of strings. Galileo here treated for the first time the bending and breaking of beams and summarized his mathematical and experimental investigations of motion, including the law of falling bodies and the parabolic path of projectiles as a result of the mixing of two motions, constant speed and uniform acceleration.
 Galileo Galilei (1595 words) Galileo tried to create this using a variety of lenses and he soon succeeded in making a basic telescope using a concave and a convex lens at either end of a lead tube. Galileo remained silent on the subject for a number of years, working on a method of determining longitudes at sea by using his predictions of the positions of Jupiter's satellites. Galileo was summoned to Rome to face the Inquisition and to stand trial for "grave suspicion of heresy." This charge was grounded on a report that Galileo had been personally ordered in 1616 not to discuss Coperican theory either orally or in writing.
More results at FactBites »

Share your thoughts, questions and commentary here

Want to know more?
Search encyclopedia, statistics and forums:

Press Releases |  Feeds | Contact