An invaluable resource for working programmers, as well as a fount of useful algorithmic tools for computer scientists, astronomers, and other calendar enthusiasts, The Ultimate Edition updates and expands the previous edition to achieve more accurate results and present new calendar variants. The book now includes coverage of Unix dates, Italian time, the Akan, Icelandic, Saudi Arabian Umm al-Qura, and Babylonian calendars. There are also expanded treatments of the observational Islamic and Hebrew calendars and brief discussions of the Samaritan and Nepalese calendars. Several of the astronomical functions have been rewritten to produce more accurate results and to include calculations of moonrise and moonset. The authors frame the calendars of the world in a completely algorithmic form, allowing easy conversion among these calendars and the determination of secular and religious holidays. LISP code for all the algorithms is available in machine-readable form.

The Gregorian calendar reform of 1582, which provided the basis for the civil and Western ecclesiastical calendars still in use today, has often been seen as a triumph of early modern scientific culture or an expression of papal ambition in the wake of the Counter-Reformation. Much less attention has been paid to reform's intellectual roots in the European Middle Ages, when the reckoning of time by means of calendrical cycles was a topic of central importance to learned culture, as impressively documented by the survival of relevant texts and tables in thousands of manuscripts copied before 1500. For centuries prior to the Gregorian reform, astronomers, mathematicians, theologians, and even Church councils had been debating the necessity of improving or emending the existing ecclesiastical calendar, which throughout the Middle Ages kept losing touch with the astronomical phenomena at an alarming pace. Scandalous Error is the first comprehensive study of the medieval literature devoted to the calendar problem and its cultural and scientific contexts. It examines how the importance of ordering liturgical time by means of a calendar that comprised both solar and lunar components posed a technical-astronomical problem to medieval society and details the often sophisticated ways in which computists and churchmen reacted to this challenge. By drawing attention to the numerous connecting paths that existed between calendars and mathematical astronomy between the Fall of Rome and the end of the fifteenth century, the volume offers substantial new insights on the place of exact science in medieval culture.

The prophet Muhammad and the early Islamic community radically redefined the concept of time that they had inherited from earlier religions' beliefs and practices. This new temporal system, based on a lunar calendar and era, was complex and required sophistication and accuracy. From the ninth to the sixteenth centuries, it was the Muslim astronomers of the Ottoman, Safavid and Mughal empires who were responsible for the major advances in mathematics, astronomy and astrology. This fascinating study compares the Islamic concept of time, and its historical and cultural significance, across these three great empires. Each empire, while mindful of earlier models, created a new temporal system, fashioning a new solar calendar and era and a new round of rituals and ceremonies from the cultural resources at hand. This book contributes to our understanding of the Muslim temporal system and our appreciation of the influence of Islamic science on the Western world.

The Letter and Prologue on Easter of Theophilus of Alexandria (385-412), the 95-year list of Paschal data compiled by Cyril (412-444), and the Prologue or Praefatio to that list written in Latin about 482 in the persona of Cyril are among the foundational documents for our knowledge of the Alexandrian Easter cycle. That cycle, through the Latin versions of Dionysius Exiguus, Bede, and others was the standard method for determining the date of Easter in the western churches until the end of the sixteenth century. There has been no modern critical edition of either Prologue since those of Bruno Krusch in 1880. This new edition of the texts is based on Alden A. Mosshammer's discovery or rediscovery of manuscript witnesses unknown to Krusch and overlooked by more recent scholars who have engaged these texts. The historical introduction summarizes current knowledge about the history of Easter calculations in early Christian communities, including a new hypothesis attributing the Alexandrian cycle in its final form to the mathematician and astronomer Theon of Alexandria working in the 370's. Although both texts have already been translated into English, Mosshammer's new translations are based on his new reconstruction of the texts. The commentaries address many issues currently under debate in historical scholarship, such as the origin of 21 March as the conventional date of the vernal equinox. The newly reconstructed text of the Prologue attributed to Cyril and Mosshammer's extensive commentary make that difficult text intelligible for the first time.

An accessible and thought-provoking introduction to timespans in the natural world, featuring more than 80 beautifully designed diagrams. Which organisms live the longest? How does the natural world recover from fire? How long do eggs take to hatch? What are the world's fastest and slowest growing plants? Which species invest the most in parental care? How Nature Keeps Time discovers the natural world's most important and intriguing patterns of time. Beautifully designed with stunning colour photography and more than 80 reader-friendly charts and diagrams, this witty book examines a broad range of species from across the world and throughout time. From the lifecycle of immortal jellyfish and identifying the perfect amount of time for a 'good sleep' to mass extinction and the destruction of the coral reef, Helen Pilcher tackles highly relevant and fascinating topics in this deeply entertaining read.

Our engagement with time is a ubiquitous feature of our lives. We are aware of time on many scales, from the briefest flicker of change to the way our lives unfold over many years. But to what extent does this encounter reveal the true nature of temporal reality? To the extent that temporal reality is as it seems, how do we come to be aware of it? And to the extent that temporal reality is not as it seems, why does it seem that way? These are the central questions addressed by Simon Prosser in Experiencing Time. These questions take on a particular importance in philosophy for two reasons. Firstly, there is a view concerning the metaphysics of time, known as the B-theory of time, according to which the apparently dynamic quality of change, the special status of the present, and even the passage of time are all illusions. Instead, the world is a four-dimensional space-time block, lacking any of the apparent dynamic features of time. If the B-theory is correct, as the book argues, then it must be explained why our experiences seem to tell us otherwise. Secondly, experiences of temporal features such as changes, rates and durations are of independent interest because of certain puzzles that they raise, the solutions to which may shed light on broader issues in the philosophy of mind.

Originally published in 1926, this book contains a general history of the measurement of time now known as the week. Colson begins with the seven-day cycle devised by the Jews and examines how different theologies gave rise to different names and systems of measurement for each day of the week and how the week eventually became standardised. This book will be of value to anyone with an interest in ancient astronomy and the history of time keeping.

As new networks of railways, steamships, and telegraph communications brought distant places into unprecedented proximity, previously minor discrepancies in local time-telling became a global problem. Vanessa Ogle's chronicle of the struggle to standardize clock times and calendars from 1870 to 1950 highlights the many hurdles that proponents of uniformity faced in establishing international standards. Time played a foundational role in nineteenth-century globalization. Growing interconnectedness prompted contemporaries to reflect on the annihilation of space and distance and to develop a global consciousness. Time-historical, evolutionary, religious, social, and legal-provided a basis for comparing the world's nations and societies, and it established hierarchies that separated "advanced" from "backward" peoples in an age when such distinctions underwrote European imperialism. Debates and disagreements on the varieties of time drew in a wide array of observers: German government officials, British social reformers, colonial administrators, Indian nationalists, Arab reformers, Muslim scholars, and League of Nations bureaucrats. Such exchanges often heightened national and regional disparities. The standardization of clock times therefore remained incomplete as late as the 1940s, and the sought-after unification of calendars never came to pass. The Global Transformation of Time reveals how globalization was less a relentlessly homogenizing force than a slow and uneven process of adoption and adaptation that often accentuated national differences.

This fascinating work begins with a scientific appraisal of time and its relationship with 3D space. It explains in clear, understandable language, the complex theories of such famous men as Newton, Einstein, and Stephen Hawking. Is time infinite, or does it have a beginning and an end? Do Black Holes and White Vortices distort time, or penetrate it? The authors also analyse and evaluate puzzling, well documented reports of time travel and reincarnation, and strange cases of deja vu. Can time travel account for such anachronistic discoveries as a 20th century sparkplug found encased among fossils half a million years old? Finally, the authors bring all the unsolved time-related mysteries together in a unified field theory that suggests an awesome answer to the mysteries of time-travel and reincarnation.

Physical Relativity explores the nature of the distinction at the heart of Einstein's 1905 formulation of his special theory of relativity: that between kinematics and dynamics. Einstein himself became increasingly uncomfortable with this distinction, and with the limitations of what he called the "principle theory" approach inspired by the logic of thermodynamics. A handful of physicists and philosophers have over the last century likewise expressed doubts about Einstein's treatment of the relativistic behavior of rigid bodies and clocks in motion in the kinematical part of his great paper, and suggested that the dynamical understanding of length contraction and time dilation intimated by the immediate precursors of Einstein is more fundamental. Harvey Brown both examines and extends these arguments (which support a more "constructive" approach to relativistic effects in Einstein's terminology), after giving a careful analysis of key features of the pre-history of relativity theory. He argues furthermore that the geometrization of the theory by Minkowski in 1908 brought illumination, but not a causal explanation of relativistic effects. Finally, Brown tries to show that the dynamical interpretation of special relativity defended in the book is consistent with the role this theory must play as a limiting case of Einstein's 1915 theory of gravity: the general theory of relativity.
Physical Relativity is an original, critical examination of the way Einstein formulated his theory. It also examines in detail certain specific historical and conceptual issues that have long given rise to debate in both special and general relativity theory, such as the conventionality of simultaneity, the principle of general covariance, and the consistency or otherwise of the special theory with quantum mechanics. Harvey Brown's new interpretation of relativity theory will interest anyone working on these central topics in modern physics.

Modern physics has revealed a universe that is a much stranger place than we could have imagined, filled with black holes and dark matter and parallel lines meeting in space. And the puzzle at the center of our present understanding of the universe is time.
Now, in The Labyrinth of Time, Michael Lockwood takes the reader on a fascinating journey into the nature of things. A brilliant writer, Lockwood illuminates the philosophical questions about past, present, and future, our experience of time, and the possibility of time travel, in a book that is both challenging and great fun. Indeed, he provides the most careful, lively, and up-to-date introduction to the physics of time and the structure of the universe to be found anywhere in print. He guides us step by step through relativity theory and quantum physics, introducing and explaining the ground-breaking ideas of Newton and Boltzmann, Einstein and Schroedinger, Penrose and Hawking. We zoom in on the behavior of molecules and atoms, and pull back to survey the expansion of the universe. We learn about entropy and gravity, black holes and wormholes, about how it all began and where we are all headed.
Lockwood's aim is not just to boggle the mind but to lead us towards an understanding of the science and philosophy. Things will never seem the same again after a voyage through The Labyrinth of Time.
A model of balance and clarity.
--Paul Davies, Times Higher Education Supplement

Brings together the output of a forty-year collaborative research project that unpicked and put into practice the fine details of John Harrison's extraordinary pendulum clock system. Harrison predicted that his unique method of making pendulum clocks could provide as much as one-hundred-times the stability of those made by his contemporaries. However, his final publication, which promised to describe the system, was a chaotic jumble of information, much of which had nothing to do with clockwork. One contemporary reviewer of Harrison's book could only suggest that the end result was a product of Harrison's 'superannuated dotage.' The focus of this book centres on the making, adjusting, and testing of Clock B which was the subject of various trials at the Royal Observatory, Greenwich. The modern history of Clock B is accompanied by scientific analysis of the clock system, Clock B's performance, the methods of data-gathering alongside historical perspectives on Harrison's clockmaking, that of his contemporaries, and some evaluation of the possible influence of early 18th century scientific thought.

Why should there be anything at all? Why, in particular, should a material world exist? Bede Rundle advances clear, non-technical answers to these perplexing questions. If, as the theist maintains, God is a being who cannot but exist, his existence explains why there is something rather than nothing. However, this can also be explained on the basis of a weaker claim. Not that there is some particular being that has to be, but simply that there has to be something or other. Rundle proffers arguments for thinking that that is indeed how the question is to be put to rest. Traditionally, the existence of the physical universe is held to depend on God, but the theist faces a major difficulty in making clear how a being outside space and time, as God is customarily conceived to be, could stand in an intelligible relation to the world, whether as its creator or as the author of events within it. Rundle argues that a creator of physical reality is not required, since there is no alternative to its existence. There has to be something, and a physical universe is the only real possibility. He supports this claim by eliminating rival contenders; he dismisses the supernatural, and argues that, while other forms of being, notably the abstract and the mental, are not reducible to the physical, they presuppose its existence. The question whether ultimate explanations can ever be given is forever in the background, and the book concludes with an investigation of this issue and of the possibility that the universe could have existed for an infinite time. Other topics discussed include causality, space, verifiability, essence, existence, necessity, spirit, fine tuning, and laws of Nature. Why There Is Something Rather Than Nothing offers an explanation of fundamental facts of existence in purely philosophical terms, without appeal either to theology or cosmology. It will provoke and intrigue anyone who wonders about these questions.

Modern physics has revealed the universe as a much stranger place than we could have imagined. The puzzle at the centre of our knowledge of the universe is time. Michael Lockwood takes the reader on a fascinating journey into the nature of things. He investigates philosophical questions about past, present, and future, our experience of time, and the possibility of time travel. And he provides the most careful, lively, and up-to-date introduction to the physics of time and the structure of the universe.He guides us step by step through relativity theory and quantum physics, introducing and explaining the ground-breaking ideas of Newton and Boltzmann, Einstein and Schroedinger, Penrose and Hawking. We zoom in on the behaviour of molecules and atoms, and pull back to survey the expansion of the universe. We learn about entropy and gravity, black holes and wormholes, about how it all began and where we are all headed. Lockwood's aim is not just to boggle the mind but to lead us towards an understanding of the science and philosophy. Things will never seem the same again after a voyage through The Labyrinth of Time.

This comprehensive collection of calendars could only have been assembled by the authors of the definitive text on calendar algorithms, Calendrical Calculations. Using the algorithms outlined in their earlier book, Reingold and Dershowitz have achieved the near impossible task of simultaneously displaying the date on thirteen different calendars over a three-hundred year period. Represented here are the Gregorian, ISO, Hebrew, Chinese, Coptic, Ethiopic, Persian, Hindu lunar, Hindu solar, and Islamic calendars; another three are easily obtained from the tables with minimal arithmetic (JD, R.D., and Julian). The tables also include phases of the moon, dates of solstices and equinoxes, and religious and other special holidays for all the calendars shown. These beautifully-produced tables will be of use for centuries by anyone with an interest in calendars and the societies that produce them.

2013 Reprint of 1923 Edition. Exact facsimile of the original edition, not reproduced with Optical Recognition Software. Sir Arthur Stanley Eddington was a British astrophysicist of the early 20th century. He was also a philosopher of science and a popularizer of science. The Eddington limit, the natural limit to the luminosity of stars, or the radiation generated by accretion onto a compact object, is named in his honor. He is also famous for his work regarding the theory of relativity. He wrote a number of articles which announced and explained Einstein's theory of general relativity to the English-speaking world. World War I severed many lines of scientific communication and new developments in German science were not well known in England, and vice versa. He also conducted an expedition to observe the Solar eclipse of 29 May 1919 that provided one of the earliest confirmations of relativity, and he became known for his popular expositions and interpretations of the theory.

IN Time:A Traveller's Guide. CLifford A. Pickover takes readers to the forefront of science as he illuminates the most mysterious phenomenon in the universe - time itself. Is time travel possible? Is time real? Does it flow in one direction only? Does it have a beginning or an end? What is eternity? These are questions that Pickover tackles in this stimulating blend of Chopin, philosophy, Einstein and modern physics, spiced with diverting side-trips to such topics as the history of clocks, the nature of free will and the reason that gold glitters. By the time we finish this book, we understand such seemingly arcane concepts as space time diagrams, light cones, cosmic moment lines, transcendent infinite speeds, Lorentz transformations, superluminal and ultra-luminal motions, closed timelike curves, and Tipler cylinders. And most important, we will understand that time travel need not be confined to myth, science fiction, Hollywood fantasies, or scientific speculation. Time travel, we will realise, is possible.

"Patience, patience, because the great movements of history have always begun in those small parenthesis that we call 'in the meantime.'" --John Berger The last book that John Berger wrote was this precious little volume about time titled What Time Is It?, now posthumously published for the first time in English by Notting Hill Editions. Berger died before it was completed, but the text has been assembled and illustrated by his longtime collaborator and friend Sel uk Demirel, and has an introduction by Maria Nadotti. What Time Is It? is a profound and playful meditation on the illusory nature of time. Berger, the great art critic and Man Booker Prize-winning author, reflects on what time has come to mean to us in modern life. Our perception of time assumes a uniform and ceaseless passing of time, yet time is turbulent. It expands and contracts according to the intensity of the lived moment. We talk of time "saved" in a hundred household appliances; time, like money, is exchanged for the content it lacks. Berger posits the idea that time can lengthen lifetimes once we seize the present moment. "What-is-to-come, what-is-to-be-gained empties what-is."

What is time? What does it mean for time to pass? Is it possible to travel in time? What is the difference between the past and future? Until the work of Newton, these questions were purely topics of philosophical speculation. Since then we've learned a great deal about time, and its study has moved from a subject of philosophical reflection to instead became part of the subject matter of physics. This Very Short Introduction introduces readers to the current physical understanding of the direction of time, from the Second Law of Thermodynamics to the emergence of complexity and life. Jenann Ismael charts the line of development in physical theory from Newton, via Einstein's Theory of Relativity, to the current day. Einstein's innovations led to a vision of time very different from the familiar time of everyday sense. In this new vision, time is one of the dimensions in which the universe is extended alongside the spatial dimensions. The universe appears as a static block of events, in which there is no more a difference between past and future than there is between east and west. Discussing the controversy and philosophical confusion which surrounded the reception of this new vision, Ismael also covers the contemporary mixture of statistical mechanics, cognitive science, and phenomenology that point the way to reconciling the familiar time of everyday sense with the vision of time presented in Einstein's theories. Very Short Introductions: Brilliant, Sharp, Inspiring ABOUT THE SERIES: The Very Short Introductions series from Oxford University Press contains hundreds of titles in almost every subject area. These pocket-sized books are the perfect way to get ahead in a new subject quickly. Our expert authors combine facts, analysis, perspective, new ideas, and enthusiasm to make interesting and challenging topics highly readable.

What is time? The 5th-century philosopher St Augustine famously said that he knew what time was, so long as no one asked him. Is time a fourth dimension similar to space or does it flow in some sense? And if it flows, does it make sense to say how fast? Does the future exist? Is time travel possible? Why does time seem to pass in only one direction? These questions and others are among the deepest and most subtle that one can ask, but Introducing Time presents them - many for the first time - in an easily accessible, lucid and engaging manner, wittily illustrated by Ralph Edney.

Sundials, which decorate church walls, public plazas, and elegant gardens, are first and foremost astronomical instruments. Before understanding how sundials work, one must first understand the apparent motion of the Sun in the sky. In this book, Denis Savoie presents the basics of astronomy required to understand sundials and describes how to design and build your own classical sundial. Written to engage all levels of science readers, the author shows the calculations involved in the sundial's construction and also gives a comprehensive history of time measurement.

The book begins with an introduction to cosmography through a study of the Sun's annual and diurnal motions. The Celestial Sphere and the local Celestial Sphere, the hour angle of the sun and the equation of Time are all discussed. The author then moves to a brief history of both sundials and time, giving the general principles behind the sundial, the conversion of solar time to clock time, and discussing the local meridian line. The gnomon and the use of its shadow are also explained in detail. In addition, many types of sundials and their different uses are described. These include the polar, horizontal, and north-facing sundial, just to name a few.

The practical and observational aspects of sundials will enable readers to create custom-made sundial of their own, adding whatever special features they wish to include. Most of these designs have been tested by people with no previous knowledge of astronomy. To aid the reader, the book is full of clear and instructive illustrations and diagrams.