Astrology is a pseudoscience that claims to divine information about human affairs and terrestrial events by studying the movements and relative positions of celestial objects. Astrology has been dated to at least the 2nd millennium BCE, has its roots in calendrical systems used to predict seasonal shifts and to interpret celestial cycles as signs of divine communications. Many cultures have attached importance to astronomical events, some—such as the Hindus and the Maya—developed elaborate systems for predicting terrestrial events from celestial observations. Western astrology, one of the oldest astrological systems still in use, can trace its roots to 19th–17th century BCE Mesopotamia, from which it spread to Ancient Greece, the Arab world and Central and Western Europe. Contemporary Western astrology is associated with systems of horoscopes that purport to explain aspects of a person's personality and predict significant events in their lives based on the positions of celestial objects.
Throughout most of its history, astrology was considered a scholarly tradition and was common in academic circles in close relation with astronomy, alchemy and medicine. It was present in political circles and is mentioned in various works of literature, from Dante Alighieri and Geoffrey Chaucer to William Shakespeare, Lope de Vega, Calderón de la Barca. Following the end of the 19th century and the wide-scale adoption of the scientific method, astrology has been challenged on both theoretical and experimental grounds, has been shown to have no scientific validity or explanatory power. Astrology thus lost its academic and theoretical standing, common belief in it has declined. While polls have demonstrated that one quarter of American and Canadian people say they continue to believe that star and planet positions affect their lives, astrology is now recognized as a pseudoscience—a belief, incorrectly presented as scientific; the word astrology comes from the early Latin word astrologia, which derives from the Greek ἀστρολογία—from ἄστρον astron and -λογία -logia.
Astrologia passed into meaning'star-divination' with astronomia used for the scientific term. Many cultures have attached importance to astronomical events, the Indians and Maya developed elaborate systems for predicting terrestrial events from celestial observations. In the West, astrology most consists of a system of horoscopes purporting to explain aspects of a person's personality and predict future events in their life based on the positions of the sun and other celestial objects at the time of their birth; the majority of professional astrologers rely on such systems. Astrology has been dated to at least the 2nd millennium BCE, with roots in calendrical systems used to predict seasonal shifts and to interpret celestial cycles as signs of divine communications. A form of astrology was practised in the first dynasty of Mesopotamia. Vedāṅga Jyotiṣa, is one of earliest known Hindu texts on astrology; the text is dated between 1400 BCE to final centuries BCE by various scholars according to astronomical and linguistic evidences.
Chinese astrology was elaborated in the Zhou dynasty. Hellenistic astrology after 332 BCE mixed Babylonian astrology with Egyptian Decanic astrology in Alexandria, creating horoscopic astrology. Alexander the Great's conquest of Asia allowed astrology to spread to Ancient Rome. In Rome, astrology was associated with'Chaldean wisdom'. After the conquest of Alexandria in the 7th century, astrology was taken up by Islamic scholars, Hellenistic texts were translated into Arabic and Persian. In the 12th century, Arabic texts were translated into Latin. Major astronomers including Tycho Brahe, Johannes Kepler and Galileo practised as court astrologers. Astrological references appear in literature in the works of poets such as Dante Alighieri and Geoffrey Chaucer, of playwrights such as Christopher Marlowe and William Shakespeare. Throughout most of its history, astrology was considered a scholarly tradition, it was accepted in political and academic contexts, was connected with other studies, such as astronomy, alchemy and medicine.
At the end of the 17th century, new scientific concepts in astronomy and physics called astrology into question. Astrology thus lost its academic and theoretical standing, common belief in astrology has declined. Astrology, in its broadest sense, is the search for meaning in the sky. Early evidence for humans making conscious attempts to measure and predict seasonal changes by reference to astronomical cycles, appears as markings on bones and cave walls, which show that lunar cycles were being noted as early as 25,000 years ago; this was a first step towards recording the Moon's influence upon tides and rivers, towards organising a communal calendar. Farmers addressed agricultural needs with increasing knowledge of the constellations that appear in the different seasons—and used the rising of particular star-groups to herald annual floods or seasonal activities. By the 3rd millennium BCE, civilisations had sophisticated awareness of celestial cycles, may have oriented temples in alignment with heliacal risings of the stars.
Scattered evidence suggests that the oldest known astrological references are copies of texts made in the ancient world. The Venus tablet of Ammisaduqa is thought to be compiled in Babylon around 1700 BCE. A scroll documenting an early use of electional astrology is doubtfully ascribed to the reign of the Sumerian ruler Gud
Ian William Ridpath is an English science writer and broadcaster best known as a popularizer of astronomy and a biographer of constellation history. As a UFO sceptic, he investigated and explained the Rendlesham Forest Incident of December 1980. Ridpath attended Beal Grammar School in Ilford where he wrote astronomy articles for the school magazine. Before entering publishing he was an assistant in the lunar research group at the University of London Observatory, Mill Hill, he now lives in Middlesex. He is editor of the Oxford Dictionary of Astronomy and Norton's Star Atlas, author of observing guides such as The Monthly Sky Guide and the Collins Stars and Planets Guide, his other books include Star Tales, about the origins and mythology of the constellations, the children's book Exploring Stars and Planets, now in its fifth edition. He is a contributor to the Dorling Kindersley encyclopedia Universe, a former editor of the UK quarterly magazine Popular Astronomy, he is currently editor of The Antiquarian Astronomer, the journal of the Society for the History of Astronomy.
His early books on the subject of extraterrestrial life and interstellar travel – Worlds Beyond, Messages from the Stars and Life off Earth – led him to investigate UFOs. But he became a sceptic, a position reinforced by his findings about the Rendlesham case, he was one of the first to offer an explanation for the so-called Sirius Mystery involving the advanced astronomical knowledge of the Dogon people of Mali, west Africa. He was a space expert for LBC Radio from the 1970s into the 1990s, was seen on BBC TV's Breakfast Time programme in its early years, it was for Breakfast Time. His star show Planet Earth ran at the London Planetarium from February 1993 to January 1995. In 2012 he received the Astronomical Society of the Pacific's Klumpke-Roberts Award for outstanding contributions to the public understanding and appreciation of astronomy. In 1990 he won an award in The Aventis Prizes for Science Books for The Giant Book of Space. From 1993 to 1995 he was Race Director of the Polytechnic Marathon from Windsor to Chiswick, Britain's oldest marathon race which traced its origins back to the 1908 Olympic Marathon.
In that role, he was involved in a public controversy over the ownership of the Sporting Life marathon trophy awarded to winners of the Polytechnic Marathon, claimed in 1994 by the London Marathon. The Polytechnic Marathon was last held in 1996. A keen astro-philatelist, he is chairman of the Astro Space Stamp Society. Stars and Planets Guide. Collins. ISBN 978-0-00-823927-5. Princeton University Press. ISBN 978-0-691-17788-5. Monthly Sky Guide. Cambridge University Press. ISBN 978-0-521-13369-2. Gem Stars. Collins. ISBN 978-0-00-717858-2. Times Universe. Times Books. ISBN 978-0-00-716930-6. Exploring Stars and Planets. Philip's. ISBN 978-1-84907-144-4. Star Tales. Lutterworth. ISBN 978-0-7188-9478-8. Oxford Dictionary of Astronomy. Oxford University Press. ISBN 978-0-19-921493-8. Norton’s Star Alas and Reference Handbook. Dutton. ISBN 978-0-13-145164-3. Personal website CV Who's Who entry Rendlesham Forest UFO investigation pages Article on astronomical causes of UFOs Star Tales – History and mythology of the constellations Astro stamp pages Ian Ridpath's page at Amazon Author Central US Ian Ridpath's page at Amazon Author Central UK
Natural history is a domain of inquiry involving organisms including animals and plants in their environment. A person who studies natural history is called natural historian. Natural history is not limited to it, it involves the systematic study of any category of natural organisms. So while it dates from studies in the ancient Greco-Roman world and the mediaeval Arabic world, through to European Renaissance naturalists working in near isolation, today's natural history is a cross discipline umbrella of many specialty sciences; the meaning of the English term "natural history" has narrowed progressively with time. In antiquity, "natural history" covered anything connected with nature, or which used materials drawn from nature, such as Pliny the Elder's encyclopedia of this title, published circa 77 to 79 AD, which covers astronomy, geography and their technology and superstition, as well as animals and plants. Medieval European academics considered knowledge to have two main divisions: the humanities and divinity, with science studied through texts rather than observation or experiment.
The study of nature revived in the Renaissance, became a third branch of academic knowledge, itself divided into descriptive natural history and natural philosophy, the analytical study of nature. In modern terms, natural philosophy corresponded to modern physics and chemistry, while natural history included the biological and geological sciences; the two were associated. During the heyday of the gentleman scientists, many people contributed to both fields, early papers in both were read at professional science society meetings such as the Royal Society and the French Academy of Sciences – both founded during the seventeenth century. Natural history had been encouraged by practical motives, such as Linnaeus' aspiration to improve the economic condition of Sweden; the Industrial Revolution prompted the development of geology to help find useful mineral deposits. Modern definitions of natural history come from a variety of fields and sources, many of the modern definitions emphasize a particular aspect of the field, creating a plurality of definitions with a number of common themes among them.
For example, while natural history is most defined as a type of observation and a subject of study, it can be defined as a body of knowledge, as a craft or a practice, in which the emphasis is placed more on the observer than on the observed. Definitions from biologists focus on the scientific study of individual organisms in their environment, as seen in this definition by Marston Bates: "Natural history is the study of animals and Plants – of organisms.... I like to think of natural history as the study of life at the level of the individual – of what plants and animals do, how they react to each other and their environment, how they are organized into larger groupings like populations and communities" and this more recent definition by D. S. Wilcove and T. Eisner: "The close observation of organisms—their origins, their evolution, their behavior, their relationships with other species"; this focus on organisms in their environment is echoed by H. W. Greene and J. B. Losos: "Natural history focuses on where organisms are and what they do in their environment, including interactions with other organisms.
It encompasses changes in internal states insofar as they pertain to what organisms do". Some definitions go further, focusing on direct observation of organisms in their environment, both past and present, such as this one by G. A. Bartholomew: "A student of natural history, or a naturalist, studies the world by observing plants and animals directly; because organisms are functionally inseparable from the environment in which they live and because their structure and function cannot be adequately interpreted without knowing some of their evolutionary history, the study of natural history embraces the study of fossils as well as physiographic and other aspects of the physical environment". A common thread in many definitions of natural history is the inclusion of a descriptive component, as seen in a recent definition by H. W. Greene: "Descriptive ecology and ethology". Several authors have argued for a more expansive view of natural history, including S. Herman, who defines the field as "the scientific study of plants and animals in their natural environments.
It is concerned with levels of organization from the individual organism to the ecosystem, stresses identification, life history, distribution and inter-relationships. It and appropriately includes an esthetic component", T. Fleischner, who defines the field more broadly, as "A practice of intentional, focused attentiveness and receptivity to the more-than-human world, guided by honesty and accuracy"; these definitions explicitly include the arts in the field of natural history, are aligned with the broad definition outlined by B. Lopez, who defines the field as the "Patient interrogation of a landscape" while referring to the natural history knowledge of the Eskimo. A different framework for natural history, covering a similar range of themes, is implied in the scope of work encompassed by many leading natural history museums, which include elements of anthropology, geology and astronomy along with botany and zoology, or include both cultural and natural components of the world; the pl
A hobby is a regular activity done for enjoyment during one's leisure time. Hobbies include collecting themed items and objects, engaging in creative and artistic pursuits, playing sports, or pursuing other amusements. Participation in hobbies encourages acquiring substantial skills and knowledge in that area. A list of hobbies changes with renewed interests and developing fashions, making it diverse and lengthy. Hobbies tend to follow trends in society, for example stamp collecting was popular during the nineteenth and twentieth centuries as postal systems were the main means of communication, while video games are more popular nowadays following technological advances; the advancing production and technology of the nineteenth century provided workers with more availability in leisure time to engage in hobbies. Because of this, the efforts of people investing in hobbies has increased with time. Hobbyists may be identified under three sub-categories: casual leisure, serious leisure, project-based leisure.
Though, some hobbyists engage in leisure pursuits that overlap multiple boundaries of the groups. Hobbies are found within the second category, serious leisure. In the 16th century, the term "hobyn" had the meaning of "small horse and pony"; the term "hobby horse" was documented in a 1557 payment confirmation for a "Hobbyhorse" from Reading, England. The item called a "Tourney Horse", was made of a wooden or basketwork frame with an artificial tail and head, it was designed for a child to mimic riding a real horse. By 1816 the derivative, "hobby", was introduced into the vocabulary of a number of English people. Over the course of subsequent centuries, the term came to be associated with leisure. In the 17th century, the term was used in a pejorative sense by suggesting that a hobby was a childish pursuit, however, in the 18th century with a more industrial society and more leisure time, hobbies took on greater respectability A hobby is called a pastime, derived from the use of hobbies to pass the time.
A hobby became an activity, practised and with some worthwhile purpose. Hobbies are but not always, practised for interest and enjoyment, rather than financial reward. Hobbies were described as pursuits that others thought somewhat childish or trivial. However, as early as 1676 Sir Matthew Hale, in Contemplations Moral and Divine, wrote "Almost every person hath some hobby horse or other wherein he prides himself." He was acknowledging. By the mid 18th century there was a flourishing of hobbies as working people had more regular hours of work and greater leisure time, they spent more time to pursue interests. However, there was concern that these working people might not use their leisure time in worthwhile pursuits. "The hope of weaning people away from bad habits by the provision of counter-attractions came to the fore in the 1830s, has waned since. The bad habits were perceived to be of a sensual and physical nature, the counter attractions, or more alternatives, deliberately cultivated rationality and the intellect."
The flourishing book and magazine trade of the day encouraged worthwhile pursuits. The burgeoning manufacturing trade made materials used in hobbies cheap and was responsive to the changing interests of hobbyists; the English have been identified as enthusiastic hobbyists. "nother English characteristic, so much a part of us that we notice it … is the addiction to hobbies and spare-time occupations, the privateness of English life. We are a nation of flower-lovers, but a nation of stamp-collectors, pigeon-fanciers, amateur carpenters, coupon-snippers, darts-players, crossword-puzzle fans. All the culture, most native centres round things which when they are communal are not official—the pub, the football match, the back garden, the fireside and the'nice cup of tea'."Deciding what to include in a list of hobbies provokes debate because it is difficult to decide which pleasurable pass-times can be described as hobbies. During the 20th century the term hobby suggested activities, such as stamp collecting, knitting, painting and photography.
The description did not include activities like listening to music, watching television, or reading. These latter activities bring pleasure, but lack the sense of achievement associated with a hobby, they are not structured, organised pursuits, as most hobbies are. The pleasure of a hobby is associated with making something of value or achieving something of value. "Such leisure is valorised because it produces feelings of satisfaction with something that looks much like work but, done of its own sake." "Hobbies are a contradiction: they take work and turn it into leisure, take leisure and turn it into work."Hobbies change with time. In the 21st century, the video game industry is a large hobby involving millions of kids and adults in various forms of'play'. Stamp collecting declined along with the importance of the postal system. Woodwork and knitting declined as hobbies, because manufactured goods provide cheap alternatives for handmade goods. Through the internet, an online community has become a hobby for many people.
Hobbyists are a part of a wider group of people engaged in leisure pursuits where the boundaries of each group overlap to some extent. The Serious Leisure Perspective groups hobbyists with amateurs and volunteers and identifies three broa
Astronomy is a natural science that studies celestial objects and phenomena. It applies mathematics and chemistry in an effort to explain the origin of those objects and phenomena and their evolution. Objects of interest include planets, stars, nebulae and comets. More all phenomena that originate outside Earth's atmosphere are within the purview of astronomy. A related but distinct subject is physical cosmology, the study of the Universe as a whole. Astronomy is one of the oldest of the natural sciences; the early civilizations in recorded history, such as the Babylonians, Indians, Nubians, Chinese and many ancient indigenous peoples of the Americas, performed methodical observations of the night sky. Astronomy has included disciplines as diverse as astrometry, celestial navigation, observational astronomy, the making of calendars, but professional astronomy is now considered to be synonymous with astrophysics. Professional astronomy is split into theoretical branches. Observational astronomy is focused on acquiring data from observations of astronomical objects, analyzed using basic principles of physics.
Theoretical astronomy is oriented toward the development of computer or analytical models to describe astronomical objects and phenomena. The two fields complement each other, with theoretical astronomy seeking to explain observational results and observations being used to confirm theoretical results. Astronomy is one of the few sciences in which amateurs still play an active role in the discovery and observation of transient events. Amateur astronomers have made and contributed to many important astronomical discoveries, such as finding new comets. Astronomy means "law of the stars". Astronomy should not be confused with astrology, the belief system which claims that human affairs are correlated with the positions of celestial objects. Although the two fields share a common origin, they are now distinct. Both of the terms "astronomy" and "astrophysics" may be used to refer to the same subject. Based on strict dictionary definitions, "astronomy" refers to "the study of objects and matter outside the Earth's atmosphere and of their physical and chemical properties," while "astrophysics" refers to the branch of astronomy dealing with "the behavior, physical properties, dynamic processes of celestial objects and phenomena."
In some cases, as in the introduction of the introductory textbook The Physical Universe by Frank Shu, "astronomy" may be used to describe the qualitative study of the subject, whereas "astrophysics" is used to describe the physics-oriented version of the subject. However, since most modern astronomical research deals with subjects related to physics, modern astronomy could be called astrophysics; some fields, such as astrometry, are purely astronomy rather than astrophysics. Various departments in which scientists carry out research on this subject may use "astronomy" and "astrophysics" depending on whether the department is affiliated with a physics department, many professional astronomers have physics rather than astronomy degrees; some titles of the leading scientific journals in this field include The Astronomical Journal, The Astrophysical Journal, Astronomy and Astrophysics. In early historic times, astronomy only consisted of the observation and predictions of the motions of objects visible to the naked eye.
In some locations, early cultures assembled massive artifacts that had some astronomical purpose. In addition to their ceremonial uses, these observatories could be employed to determine the seasons, an important factor in knowing when to plant crops and in understanding the length of the year. Before tools such as the telescope were invented, early study of the stars was conducted using the naked eye; as civilizations developed, most notably in Mesopotamia, Persia, China and Central America, astronomical observatories were assembled and ideas on the nature of the Universe began to develop. Most early astronomy consisted of mapping the positions of the stars and planets, a science now referred to as astrometry. From these observations, early ideas about the motions of the planets were formed, the nature of the Sun and the Earth in the Universe were explored philosophically; the Earth was believed to be the center of the Universe with the Sun, the Moon and the stars rotating around it. This is known as the geocentric model of the Ptolemaic system, named after Ptolemy.
A important early development was the beginning of mathematical and scientific astronomy, which began among the Babylonians, who laid the foundations for the astronomical traditions that developed in many other civilizations. The Babylonians discovered. Following the Babylonians, significant advances in astronomy were made in ancient Greece and the Hellenistic world. Greek astronomy is characterized from the start by seeking a rational, physical explanation for celestial phenomena. In the 3rd century BC, Aristarchus of Samos estimated the size and distance of the Moon and Sun, he proposed a model of the Solar System where the Earth and planets rotated around the Sun, now called the heliocentric model. In the 2nd century BC, Hipparchus discovered precession, calculated the size and distance of the Moon and inven
A star is type of astronomical object consisting of a luminous spheroid of plasma held together by its own gravity. The nearest star to Earth is the Sun. Many other stars are visible to the naked eye from Earth during the night, appearing as a multitude of fixed luminous points in the sky due to their immense distance from Earth; the most prominent stars were grouped into constellations and asterisms, the brightest of which gained proper names. Astronomers have assembled star catalogues that identify the known stars and provide standardized stellar designations. However, most of the estimated 300 sextillion stars in the Universe are invisible to the naked eye from Earth, including all stars outside our galaxy, the Milky Way. For at least a portion of its life, a star shines due to thermonuclear fusion of hydrogen into helium in its core, releasing energy that traverses the star's interior and radiates into outer space. All occurring elements heavier than helium are created by stellar nucleosynthesis during the star's lifetime, for some stars by supernova nucleosynthesis when it explodes.
Near the end of its life, a star can contain degenerate matter. Astronomers can determine the mass, age and many other properties of a star by observing its motion through space, its luminosity, spectrum respectively; the total mass of a star is the main factor. Other characteristics of a star, including diameter and temperature, change over its life, while the star's environment affects its rotation and movement. A plot of the temperature of many stars against their luminosities produces a plot known as a Hertzsprung–Russell diagram. Plotting a particular star on that diagram allows the age and evolutionary state of that star to be determined. A star's life begins with the gravitational collapse of a gaseous nebula of material composed of hydrogen, along with helium and trace amounts of heavier elements; when the stellar core is sufficiently dense, hydrogen becomes converted into helium through nuclear fusion, releasing energy in the process. The remainder of the star's interior carries energy away from the core through a combination of radiative and convective heat transfer processes.
The star's internal pressure prevents it from collapsing further under its own gravity. A star with mass greater than 0.4 times the Sun's will expand to become a red giant when the hydrogen fuel in its core is exhausted. In some cases, it will fuse heavier elements in shells around the core; as the star expands it throws a part of its mass, enriched with those heavier elements, into the interstellar environment, to be recycled as new stars. Meanwhile, the core becomes a stellar remnant: a white dwarf, a neutron star, or if it is sufficiently massive a black hole. Binary and multi-star systems consist of two or more stars that are gravitationally bound and move around each other in stable orbits; when two such stars have a close orbit, their gravitational interaction can have a significant impact on their evolution. Stars can form part of a much larger gravitationally bound structure, such as a star cluster or a galaxy. Stars have been important to civilizations throughout the world, they have used for celestial navigation and orientation.
Many ancient astronomers believed that stars were permanently affixed to a heavenly sphere and that they were immutable. By convention, astronomers grouped stars into constellations and used them to track the motions of the planets and the inferred position of the Sun; the motion of the Sun against the background stars was used to create calendars, which could be used to regulate agricultural practices. The Gregorian calendar used nearly everywhere in the world, is a solar calendar based on the angle of the Earth's rotational axis relative to its local star, the Sun; the oldest dated star chart was the result of ancient Egyptian astronomy in 1534 BC. The earliest known star catalogues were compiled by the ancient Babylonian astronomers of Mesopotamia in the late 2nd millennium BC, during the Kassite Period; the first star catalogue in Greek astronomy was created by Aristillus in 300 BC, with the help of Timocharis. The star catalog of Hipparchus included 1020 stars, was used to assemble Ptolemy's star catalogue.
Hipparchus is known for the discovery of the first recorded nova. Many of the constellations and star names in use today derive from Greek astronomy. In spite of the apparent immutability of the heavens, Chinese astronomers were aware that new stars could appear. In 185 AD, they were the first to observe and write about a supernova, now known as the SN 185; the brightest stellar event in recorded history was the SN 1006 supernova, observed in 1006 and written about by the Egyptian astronomer Ali ibn Ridwan and several Chinese astronomers. The SN 1054 supernova, which gave birth to the Crab Nebula, was observed by Chinese and Islamic astronomers. Medieval Islamic astronomers gave Arabic names to many stars that are still used today and they invented numerous astronomical instruments that could compute the positions of the stars, they built the first large observatory research institutes for the purpose of producing Zij star catalogues. Among these, the Book of Fixed Stars was written by the Persian astronomer Abd al-Rahman al-Sufi, who observed a number of stars, star clusters and galaxies.
According to A. Zahoor, in the 11th century, the Persian polymath scholar Abu Rayhan Biruni described the Milky