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Natural science
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Natural science is a branch of science concerned with the description, prediction, and understanding of natural phenomena, based on observational and empirical evidence. Mechanisms such as review and repeatability of findings are used to try to ensure the validity of scientific advances. Natural science can be divided into two branches, life science and physical science. Physical science is subdivided into branches, including physics, space science, chemistry and these branches of natural science may be further divided into more specialized branches. Modern natural science succeeded more classical approaches to natural philosophy, usually traced to ancient Greece, galileo, Descartes, Francis Bacon, and Newton debated the benefits of using approaches which were more mathematical and more experimental in a methodical way. Still, philosophical perspectives, conjectures, and presuppositions, often overlooked, systematic data collection, including discovery science, succeeded natural history, which emerged in the 16th century by describing and classifying plants, animals, minerals, and so on. Today, natural history suggests observational descriptions aimed at popular audiences, philosophers of science have suggested a number of criteria, including Karl Poppers controversial falsifiability criterion, to help them differentiate scientific endeavors from non-scientific ones. Validity, accuracy, and quality control, such as peer review and this field encompasses a set of disciplines that examines phenomena related to living organisms. The scale of study can range from sub-component biophysics up to complex ecologies, biology is concerned with the characteristics, classification and behaviors of organisms, as well as how species were formed and their interactions with each other and the environment. The biological fields of botany, zoology, and medicine date back to periods of civilization. However, it was not until the 19th century that became a unified science. Once scientists discovered commonalities between all living things, it was decided they were best studied as a whole, modern biology is divided into subdisciplines by the type of organism and by the scale being studied. Molecular biology is the study of the chemistry of life, while cellular biology is the examination of the cell. At a higher level, anatomy and physiology looks at the internal structures, constituting the scientific study of matter at the atomic and molecular scale, chemistry deals primarily with collections of atoms, such as gases, molecules, crystals, and metals. The composition, statistical properties, transformations and reactions of these materials are studied, chemistry also involves understanding the properties and interactions of individual atoms and molecules for use in larger-scale applications. Most chemical processes can be studied directly in a laboratory, using a series of techniques for manipulating materials, chemistry is often called the central science because of its role in connecting the other natural sciences. Early experiments in chemistry had their roots in the system of Alchemy, the science of chemistry began to develop with the work of Robert Boyle, the discoverer of gas, and Antoine Lavoisier, who developed the theory of the Conservation of mass. The success of science led to a complementary chemical industry that now plays a significant role in the world economy
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Ancient Greek philosophy
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Ancient Greek philosophy arose in the 6th century BC and continued throughout the Hellenistic period and the period in which Ancient Greece was part of the Roman Empire. Philosophy was used to sense out of the world in a non-religious way. It dealt with a variety of subjects, including political philosophy, ethics, metaphysics, ontology, logic, biology, rhetoric. Many philosophers around the world agree that Greek philosophy has influenced much of Western culture since its inception, alfred North Whitehead once noted, The safest general characterization of the European philosophical tradition is that it consists of a series of footnotes to Plato. Clear, unbroken lines of lead from ancient Greek and Hellenistic philosophers to Early Islamic philosophy, the European Renaissance. Some claim that Greek philosophy, in turn, was influenced by the wisdom literature. But they taught themselves to reason, Philosophy as we understand it is a Greek creation. Subsequent philosophic tradition was so influenced by Socrates as presented by Plato that it is conventional to refer to philosophy developed prior to Socrates as pre-Socratic philosophy. The periods following this, up to and after the wars of Alexander the Great, are those of classical Greek, the pre-Socratics were primarily concerned with cosmology, ontology and mathematics. They were distinguished from non-philosophers insofar as they rejected mythological explanations in favor of reasoned discourse, Thales of Miletus, regarded by Aristotle as the first philosopher, held that all things arise from water. It is not because he gave a cosmogony that John Burnet calls him the first man of science, according to tradition, Thales was able to predict an eclipse and taught the Egyptians how to measure the height of the pyramids. He began from the observation that the world seems to consist of opposites, therefore, they cannot truly be opposites but rather must both be manifestations of some underlying unity that is neither. This underlying unity could not be any of the classical elements, for example, water is wet, the opposite of dry, while fire is dry, the opposite of wet. Anaximenes in turn held that the arche was air, although John Burnet argues that by this he meant that it was a transparent mist, the aether. Xenophanes was born in Ionia, where the Milesian school was at its most powerful, Burnet says that Xenophanes was not, however, a scientific man, with many of his naturalistic explanations having no further support than that they render the Homeric gods superfluous or foolish. He has been claimed as an influence on Eleatic philosophy, although that is disputed, and a precursor to Epicurus, a representative of a total break between science and religion. Pythagoras lived at roughly the time that Xenophanes did and, in contrast to the latter. Parmenides of Elea cast his philosophy against those who held it is and is not the same, and all travel in opposite directions, —presumably referring to Heraclitus
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Aristotle
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Aristotle was an ancient Greek philosopher and scientist born in the city of Stagira, Chalkidice, on the northern periphery of Classical Greece. His father, Nicomachus, died when Aristotle was a child, at seventeen or eighteen years of age, he joined Platos Academy in Athens and remained there until the age of thirty-seven. Shortly after Plato died, Aristotle left Athens and, at the request of Philip II of Macedon, teaching Alexander the Great gave Aristotle many opportunities and an abundance of supplies. He established a library in the Lyceum which aided in the production of many of his hundreds of books and he believed all peoples concepts and all of their knowledge was ultimately based on perception. Aristotles views on natural sciences represent the groundwork underlying many of his works, Aristotles views on physical science profoundly shaped medieval scholarship. Their influence extended from Late Antiquity and the Early Middle Ages into the Renaissance, some of Aristotles zoological observations, such as on the hectocotyl arm of the octopus, were not confirmed or refuted until the 19th century. His works contain the earliest known study of logic, which was incorporated in the late 19th century into modern formal logic. Aristotle was well known among medieval Muslim intellectuals and revered as The First Teacher and his ethics, though always influential, gained renewed interest with the modern advent of virtue ethics. All aspects of Aristotles philosophy continue to be the object of academic study today. Though Aristotle wrote many elegant treatises and dialogues – Cicero described his style as a river of gold – it is thought that only around a third of his original output has survived. Aristotle, whose means the best purpose, was born in 384 BC in Stagira, Chalcidice. His father Nicomachus was the physician to King Amyntas of Macedon. Aristotle was orphaned at a young age, although there is little information on Aristotles childhood, he probably spent some time within the Macedonian palace, making his first connections with the Macedonian monarchy. At the age of seventeen or eighteen, Aristotle moved to Athens to continue his education at Platos Academy and he remained there for nearly twenty years before leaving Athens in 348/47 BC. Aristotle then accompanied Xenocrates to the court of his friend Hermias of Atarneus in Asia Minor, there, he traveled with Theophrastus to the island of Lesbos, where together they researched the botany and zoology of the island. Aristotle married Pythias, either Hermiass adoptive daughter or niece and she bore him a daughter, whom they also named Pythias. Soon after Hermias death, Aristotle was invited by Philip II of Macedon to become the tutor to his son Alexander in 343 BC, Aristotle was appointed as the head of the royal academy of Macedon. During that time he gave not only to Alexander
4.
Common Era
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Common Era or Current Era is a year-numbering system for the Julian and Gregorian calendars that refers to the years since the start of this era, i. e. since AD1. The preceding era is referred to as before the Common or Current Era, the Current Era notation system can be used as a secular alternative to the Dionysian era system, which distinguishes eras as AD and BC. The two notation systems are equivalent, thus 2017 CE corresponds to AD2017 and 400 BCE corresponds to 400 BC. The year-numbering system for the Gregorian calendar is the most widespread civil calendar used in the world today. For decades, it has been the standard, recognized by international institutions such as the United Nations. The expression has been traced back to Latin usage to 1615, as vulgaris aerae, the term Common Era can be found in English as early as 1708, and became more widely used in the mid-19th century by Jewish academics. He attempted to number years from a reference date, an event he referred to as the Incarnation of Jesus. Dionysius labeled the column of the table in which he introduced the new era as Anni Domini Nostri Jesu Christi, numbering years in this manner became more widespread in Europe with its usage by Bede in England in 731. Bede also introduced the practice of dating years before what he supposed was the year of birth of Jesus, in 1422, Portugal became the last Western European country to switch to the system begun by Dionysius. The first use of the Latin term vulgaris aerae discovered so far was in a 1615 book by Johannes Kepler, Kepler uses it again in a 1616 table of ephemerides, and again in 1617. A1635 English edition of that book has the title page in English – so far, a 1701 book edited by John LeClerc includes Before Christ according to the Vulgar Æra,6. A1716 book in English by Dean Humphrey Prideaux says, before the beginning of the vulgar æra, a 1796 book uses the term vulgar era of the nativity. The first so-far-discovered usage of Christian Era is as the Latin phrase aerae christianae on the page of a 1584 theology book. In 1649, the Latin phrase æræ Christianæ appeared in the title of an English almanac, a 1652 ephemeris is the first instance so-far-found for English usage of Christian Era. The English phrase common Era appears at least as early as 1708, a 1759 history book uses common æra in a generic sense, to refer to the common era of the Jews. The first-so-far found usage of the phrase before the era is in a 1770 work that also uses common era and vulgar era as synonyms. The 1797 edition of the Encyclopædia Britannica uses the terms vulgar era, the Catholic Encyclopedia in at least one article reports all three terms being commonly understood by the early 20th century. Thus, the era of the Jews, the common era of the Mahometans, common era of the world
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Physics (Aristotle)
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The Physics of Aristotle is one of the foundational books of Western science and philosophy. As Martin Heidegger once wrote, The Physics is a lecture in which he seeks to determine beings that arise on their own, τὰ φύσει ὄντα, with regard to their being. This book determines the warp and woof of the whole of Western thinking, even at that place where it, as modern thinking, but opposition is invariably comprised of a decisive, and often even perilous, dependence. Without Aristotles Physics there would have been no Galileo, bertrand Russell, however, says of Physics and On the Heavens that they were. extremely influential, and dominated science until the time of Galileo. The historian of philosophy, accordingly, must study them, in spite of the fact that hardly a sentence in either can be accepted in the light of modern science. The chief purpose of the work is to discover the principles and causes of change, or movement, or motion, the Physics is composed of eight books, which are further divided into chapters. In this article, books are referenced with Roman numerals, chapters with Arabic numerals, additionally, the Bekker numbers give the page and line numbers used in the Prussian Academy of Sciences edition of Aristotles works. Book I discusses the scientists approach to nature and the world of changing things, Topics include, remarks on method, a discussion of how some ancestors viewed nature, and the basic elements of change. Change elements include, a lack, which is overcome by its opposite, the 1966 monograph by Connell is a particularly good expansion and defense of the contents of this book. Aristotles approach to the world as summarized in chapter 1 is to start with the most general albeit vague aspects of the world before proceeding to specifics. This approach contrasts sharply with that of science, which starts with particulars before advancing to generalities. Chapter 2 begins his consideration of the first principles of motion by initiating a review of the opinions of previous thinkers, chapters 3 and 4 are among the most difficult in all of Aristotles works and involve subtle refutations of the thought of Parmenides, Melissus and Anaxagoras. In chapter 5, he continues his review of his predecessors, chapter 6 narrows down the number of principles to two or three. He presents his own account of the subject in chapter 7, Aristotles concept of matter is rather different from what we moderns might expect from the use of the word in modern mathematical science. Descartes axiomatically redefined the concept of matter in the Enlightenment to exclude any characteristics that would make it unsuitable for abstract, mathematical treatment, the matter is not specifically described, but consists of whatever remains in the change of substance from grass to horse. Matter in this understanding does not exist independently, but exists interdependently with form, Matter and form are analogical terms. It is helpful to conceive of the relationship of matter and form as very similar to that between parts and whole, parts existing separately do not remain parts, but become new wholes. Book II introduces the term nature as a source or cause of being moved, thus, those entities are natural which are capable of starting to move, e. g. growing, acquiring qualities, displacing themselves, and finally being born and dying
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Philosophy of mind
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Philosophy of mind is a branch of philosophy that studies the nature of the mind. The mind–body problem is an issue in philosophy of mind, although other issues are addressed, such as the hard problem of consciousness. Dualism and monism are the two schools of thought on the mind–body problem, although nuanced views have arisen that do not fit one or the other category neatly. Dualism is seen even in the Eastern tradition, in the Sankhya and Yoga schools of Hindu philosophy, and Plato, monism is the position that mind and body are not ontologically distinct kinds of entities. This view was first advocated in Western philosophy by Parmenides in the 5th century BC and was later espoused by the 17th century rationalist Baruch Spinoza. Physicalists argue that only entities postulated by physical theory exist, physicalists maintain various positions on the prospects of reducing mental properties to physical properties, and the ontological status of such mental properties remains unclear. Idealists maintain that the mind is all that exists and that the world is either mental itself. The most common monisms in the 20th and 21st centuries have all been variations of physicalism, these positions include behaviorism, most modern philosophers of mind adopt either a reductive or non-reductive physicalist position, maintaining in their different ways that the mind is not something separate from the body. These approaches have been influential in the sciences, especially in the fields of sociobiology, computer science, evolutionary psychology. Reductive physicalists assert that all states and properties will eventually be explained by scientific accounts of physiological processes and states. Continued neuroscientific progress has helped to some of these issues, however. Modern philosophers of mind continue to ask how the subjective qualities, the mind–body problem concerns the explanation of the relationship that exists between minds, or mental processes, and bodily states or processes. The main aim of working in this area is to determine the nature of the mind and mental states/processes. Someones desire for a slice of pizza, for example, will tend to cause that person to move his or her body in a specific manner and in a specific direction to obtain what he or she wants. The question, then, is how it can be possible for conscious experiences to arise out of a lump of gray matter endowed with nothing, a related problem is how someones propositional attitudes cause that individuals neurons to fire and his muscles to contract. These comprise some of the puzzles that have confronted epistemologists and philosophers of mind from at least the time of René Descartes, Dualism is a set of views about the relationship between mind and matter. It begins with the claim that mental phenomena are, in some respects, One of the earliest known formulations of mind–body dualism was expressed in the eastern Sankhya and Yoga schools of Hindu philosophy, which divided the world into purusha and prakriti. Specifically, the Yoga Sutra of Patanjali presents an approach to the nature of the mind
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Memory
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Memory is the faculty of the mind by which information is encoded, stored, and retrieved. Memory is vital to experiences and related to systems, it is the retention of information over time for the purpose of influencing future action. If we could not remember past events, we could not learn or develop language, relationships, often memory is understood as an informational processing system with explicit and implicit functioning that is made up of a sensory processor, short-term memory, and long-term memory. The sensory processor allows information from the world to be sensed in the form of chemical and physical stimuli and attended to with various levels of focus. Working memory serves as an encoding and retrieval processor, information in the form of stimuli is encoded in accordance with explicit or implicit functions by the working memory processor. The working memory also retrieves information from previously stored material, finally, the function of long-term memory is to store data through various categorical models or systems. Explicit and implicit functions of memory are known as declarative and non-declarative systems. These systems involve the purposeful intention of memory retrieval and storage, declarative, or explicit, memory is the conscious storage and recollection of data. Under declarative memory resides semantic and episodic memory, semantic memory refers to memory that is encoded with specific meaning, while episodic memory refers to information that is encoded along a spatial and temporal plane. Declarative memory is usually the primary process thought of when referencing memory, non-declarative, or implicit, memory is the unconscious storage and recollection of information. An example of a process would be the unconscious learning or retrieval of information by way of procedural memory. Memory is not a processor, and is affected by many factors. The manner information is encoded, stored, and retrieved can all be corrupted, the amount of attention given new stimuli can diminish the amount of information that becomes encoded for storage. Also, the process can become corrupted by physical damage to areas of the brain that are associated with memory storage. Finally, the retrieval of information from long-term memory can be disrupted because of decay within long-term memory, normal functioning, decay over time, and brain damage all affect the accuracy and capacity of memory. Sensory memory holds sensory information less than one second after an item is perceived, the ability to look at an item and remember what it looked like with just a split second of observation, or memorization, is the example of sensory memory. It is out of control and is an automatic response. With very short presentations, participants often report that they seem to see more than they can actually report, the first experiments exploring this form of sensory memory were precisely conducted by George Sperling using the partial report paradigm
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Anatomy
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Anatomy is the branch of biology concerned with the study of the structure of organisms and their parts. Anatomy is inherently tied to embryology, comparative anatomy, evolutionary biology, Human anatomy is one of the basic essential sciences of medicine. The discipline of anatomy is divided into macroscopic and microscopic anatomy, macroscopic anatomy, or gross anatomy, is the examination of an animals body parts using unaided eyesight. Gross anatomy also includes the branch of superficial anatomy, microscopic anatomy involves the use of optical instruments in the study of the tissues of various structures, known as histology, and also in the study of cells. The history of anatomy is characterized by an understanding of the functions of the organs. Anatomy and physiology, which study the structure and function of organisms and their parts, make a pair of related disciplines. Derived from the Greek ἀνατομή anatomē dissection, anatomy is the study of the structure of organisms including their systems, organs. It includes the appearance and position of the parts, the materials from which they are composed, their locations. Anatomy is quite distinct from physiology and biochemistry, which deal respectively with the functions of those parts, the discipline of anatomy can be subdivided into a number of branches including gross or macroscopic anatomy and microscopic anatomy. Gross anatomy is the study of large enough to be seen with the naked eye, and also includes superficial anatomy or surface anatomy. Microscopic anatomy is the study of structures on a scale, including histology. Anatomy can be studied using both invasive and non-invasive methods with the goal of obtaining information about the structure and organization of organs, angiography using X-rays or magnetic resonance angiography are methods to visualize blood vessels. The term anatomy is commonly taken to refer to human anatomy, however, substantially the same structures and tissues are found throughout the rest of the animal kingdom and the term also includes the anatomy of other animals. The term zootomy is also used to specifically refer to animals. The structure and tissues of plants are of a dissimilar nature, the kingdom Animalia or metazoa, contains multicellular organisms that are heterotrophic and motile. Most animals have bodies differentiated into separate tissues and these animals are known as eumetazoans. They have a digestive chamber, with one or two openings, the gametes are produced in multicellular sex organs, and the zygotes include a blastula stage in their embryonic development. Metazoans do not include the sponges, which have undifferentiated cells, unlike plant cells, animal cells have neither a cell wall nor chloroplasts
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Biology
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Biology is a natural science concerned with the study of life and living organisms, including their structure, function, growth, evolution, distribution, identification and taxonomy. Modern biology is a vast and eclectic field, composed of branches and subdisciplines. However, despite the broad scope of biology, there are certain unifying concepts within it that consolidate it into single, coherent field. In general, biology recognizes the cell as the unit of life, genes as the basic unit of heredity. It is also understood today that all organisms survive by consuming and transforming energy and by regulating their internal environment to maintain a stable, the term biology is derived from the Greek word βίος, bios, life and the suffix -λογία, -logia, study of. The Latin-language form of the term first appeared in 1736 when Swedish scientist Carl Linnaeus used biologi in his Bibliotheca botanica, the first German use, Biologie, was in a 1771 translation of Linnaeus work. In 1797, Theodor Georg August Roose used the term in the preface of a book, karl Friedrich Burdach used the term in 1800 in a more restricted sense of the study of human beings from a morphological, physiological and psychological perspective. The science that concerns itself with these objects we will indicate by the biology or the doctrine of life. Although modern biology is a recent development, sciences related to. Natural philosophy was studied as early as the ancient civilizations of Mesopotamia, Egypt, the Indian subcontinent, however, the origins of modern biology and its approach to the study of nature are most often traced back to ancient Greece. While the formal study of medicine back to Hippocrates, it was Aristotle who contributed most extensively to the development of biology. Especially important are his History of Animals and other works where he showed naturalist leanings, and later more empirical works that focused on biological causation and the diversity of life. Aristotles successor at the Lyceum, Theophrastus, wrote a series of books on botany that survived as the most important contribution of antiquity to the plant sciences, even into the Middle Ages. Scholars of the medieval Islamic world who wrote on biology included al-Jahiz, Al-Dīnawarī, who wrote on botany, biology began to quickly develop and grow with Anton van Leeuwenhoeks dramatic improvement of the microscope. It was then that scholars discovered spermatozoa, bacteria, infusoria, investigations by Jan Swammerdam led to new interest in entomology and helped to develop the basic techniques of microscopic dissection and staining. Advances in microscopy also had a impact on biological thinking. In the early 19th century, a number of biologists pointed to the importance of the cell. Thanks to the work of Robert Remak and Rudolf Virchow, however, meanwhile, taxonomy and classification became the focus of natural historians
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Corpus Aristotelicum
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The Corpus Aristotelicum is the collection of Aristotles works that have survived from antiquity through Medieval manuscript transmission. These texts, as opposed to Aristotles lost works, are technical philosophical treatises from within Aristotles school, reference to them is made according to the organization of Immanuel Bekkers nineteenth-century edition, which in turn is based on ancient classifications of these works. The extant works of Aristotle are broken down according to the five categories in the Corpus Aristotelicum, not all of these works are considered genuine, but differ with respect to their connection to Aristotle, his associates and his views. Some are regarded by most scholars as products of Aristotles school, other works, such as On Colors, may have been products of Aristotles successors at the Lyceum, e. g. Theophrastus and Strato of Lampsacus. Still others acquired Aristotles name through similarities in doctrine or content, such as the De Plantis, a final category, omitted here, includes medieval palmistries, astrological and magical texts whose connection to Aristotle is purely fanciful and self-promotional. In several of the treatises, there are references to works in the corpus. Based on such references, some scholars have suggested a possible order for a number of Aristotles writings. W. D. Ross, for instance, suggested the following chronology, Categories, Topics, Sophistici Elenchi, Analytics, Metaphysics Δ, the physical works, the Ethics. Many modern scholars, however, based simply on lack of evidence, are skeptical of such attempts to determine the order of Aristotles writings. According to a distinction that originates with Aristotle himself, his writings are divisible into two groups, the exoteric and the esoteric. Most scholars have understood this as a distinction between works Aristotle intended for the public, and the technical works intended for use within the Lyceum course / school. Modern scholars commonly assume these latter to be Aristotles own lecture notes, however, one classic scholar offers an alternative interpretation. Bekker numbers, the form of reference to works in the Corpus Aristotelicum, are based on the page numbers used in the Prussian Academy of Sciences edition of the complete works of Aristotle. They take their name from the editor of edition, the classical philologist August Immanuel Bekker. The titles are given in accordance with the set by the Revised Oxford Translation. Latin titles, still used by scholars, are also given. The Constitution of the Athenians was not included in Bekkers edition because it was first edited in 1891 from papyrus rolls acquired in 1890 by the British Museum, the standard reference to it is by section numbers. Surviving fragments of the many lost works of Aristotle were included in the volume of Bekkers edition
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Nature (philosophy)
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Nature has two inter-related meanings in philosophy. On the one hand, it means the set of all things which are natural, on the other hand, it means the essential properties and causes of individual things. The study of things and the regular laws which seem to govern them. Understandings of nature depend on the subject and age of the work where they appear, the Physics is Aristotles principal work on nature. In Physics II.1, Aristotle defines a nature as a source or cause of being moved, in other words, a nature is the principle within a natural raw material that is the source of tendencies to change or rest in a particular way unless stopped. For example, a rock would fall unless stopped, natural things stand in contrast to artifacts, which are formed by human artifice, not because of an innate tendency. In terms of Aristotles theory of four causes, the natural is applied both to the innate potential of matter cause and the forms which the matter tends to become naturally. In ancient Greek philosophy on the hand, Nature or natures are ways that are really universal in all times and places. What makes nature different is that it not only that not all customs and ways are equal. To put this discovery or invention into the terminology, what is by nature is contrasted to what is by convention. The concept of nature taken this far remains a tradition in modern western thinking. Science, according to Strauss commentary of Western history is the contemplation of nature, whether it was intended or not, Aristotles inquiries into this subject were long felt to have resolved the discussion about nature in favor of one solution. In this account, there are four different types of cause, one of the causes of a statue being what it is might be that it is bronze. All meanings of the word nature encompass this simple meaning, the efficient cause is the motion of another thing, which makes a thing change, for example a chisel hitting a rock causes a chip to break off. This is the way which the matter is forming into a form so that it become substance like what Aristotle said that a substance must have a form and this is the motion of changing a single being into two. This is the most obvious way in which cause and effect works, but according to Aristotle, this does not yet explain that of which the motion is, and we must apply ourselves to the question whether there is any other cause per se besides matter. The final cause is the aim towards which something is directed, for example, a human aims at something perceived to be good, as Aristotle says in the opening lines of the Nicomachean Ethics. The formal and final cause are a part of Aristotles Metaphysics - his attempt to go beyond nature
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Physics
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Physics is the natural science that involves the study of matter and its motion and behavior through space and time, along with related concepts such as energy and force. One of the most fundamental disciplines, the main goal of physics is to understand how the universe behaves. Physics is one of the oldest academic disciplines, perhaps the oldest through its inclusion of astronomy, Physics intersects with many interdisciplinary areas of research, such as biophysics and quantum chemistry, and the boundaries of physics are not rigidly defined. New ideas in physics often explain the mechanisms of other sciences while opening new avenues of research in areas such as mathematics. Physics also makes significant contributions through advances in new technologies that arise from theoretical breakthroughs, the United Nations named 2005 the World Year of Physics. Astronomy is the oldest of the natural sciences, the stars and planets were often a target of worship, believed to represent their gods. While the explanations for these phenomena were often unscientific and lacking in evidence, according to Asger Aaboe, the origins of Western astronomy can be found in Mesopotamia, and all Western efforts in the exact sciences are descended from late Babylonian astronomy. The most notable innovations were in the field of optics and vision, which came from the works of many scientists like Ibn Sahl, Al-Kindi, Ibn al-Haytham, Al-Farisi and Avicenna. The most notable work was The Book of Optics, written by Ibn Al-Haitham, in which he was not only the first to disprove the ancient Greek idea about vision, but also came up with a new theory. In the book, he was also the first to study the phenomenon of the pinhole camera, many later European scholars and fellow polymaths, from Robert Grosseteste and Leonardo da Vinci to René Descartes, Johannes Kepler and Isaac Newton, were in his debt. Indeed, the influence of Ibn al-Haythams Optics ranks alongside that of Newtons work of the same title, the translation of The Book of Optics had a huge impact on Europe. From it, later European scholars were able to build the devices as what Ibn al-Haytham did. From this, such important things as eyeglasses, magnifying glasses, telescopes, Physics became a separate science when early modern Europeans used experimental and quantitative methods to discover what are now considered to be the laws of physics. Newton also developed calculus, the study of change, which provided new mathematical methods for solving physical problems. The discovery of new laws in thermodynamics, chemistry, and electromagnetics resulted from greater research efforts during the Industrial Revolution as energy needs increased, however, inaccuracies in classical mechanics for very small objects and very high velocities led to the development of modern physics in the 20th century. Modern physics began in the early 20th century with the work of Max Planck in quantum theory, both of these theories came about due to inaccuracies in classical mechanics in certain situations. Quantum mechanics would come to be pioneered by Werner Heisenberg, Erwin Schrödinger, from this early work, and work in related fields, the Standard Model of particle physics was derived. Areas of mathematics in general are important to this field, such as the study of probabilities, in many ways, physics stems from ancient Greek philosophy
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Aristarchus of Samos
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Aristarchus of Samos was an ancient Greek astronomer and mathematician who presented the first known model that placed the Sun at the center of the known universe with the Earth revolving around it. He was influenced by Philolaus of Croton, but he identified the central fire with the Sun, like Anaxagoras before him, he suspected that the stars were just other bodies like the Sun, albeit further away from Earth. His astronomical ideas were rejected in favor of the geocentric theories of Aristotle and Ptolemy. Nicolaus Copernicus had attributed the theory to Aristarchus. This is the account as you have heard from astronomers. Since stellar parallax is only detectable with telescopes, his accurate speculation was unprovable at the time and it is a common misconception that the heliocentric view was held as sacrilegious by the contemporaries of Aristarchus. This is due to Gilles Ménages translation of a passage from Plutarchs On the Apparent Face in the Orb of the Moon. Plutarch reported that Cleanthes as a worshipper of the Sun and opponent to the model, was jokingly told by Aristarchus that he should be charged with impiety. Gilles Ménage, shortly after the trials of Galileo and Giordano Bruno, amended an accusative with a nominative, the resulting misconception of an isolated and persecuted Aristarchus is still transmitted today. In his Naturalis Historia, Pliny the Elder later wondered whether errors in the predictions about the heavens could be attributed to a displacement of the Earth from its central position. Pliny and Seneca referred to planets retrograde motion as an apparent phenomenon, still, no stellar parallax was observed, and Plato, Aristotle and Ptolemy preferred the geocentric model, which was held as true throughout the Middle Ages. The heliocentric theory was revived by Copernicus, after which Johannes Kepler described planetary motions with greater accuracy with his three laws, isaac Newton later gave a theoretical explanation based on laws of gravitational attraction and dynamics. The only surviving work attributed to Aristarchus, On the Sizes and Distances of the Sun. The discrepancy may come from a misinterpretation of what unit of measure was meant by a certain Greek term in Aristarchus text, Aristarchus claimed that at half moon, the angle between the Sun and Moon was 87°. He might have proposed 87° as a bound, since gauging the lunar terminators deviation from linearity to 1° accuracy is beyond the unaided human ocular limit. Aristarchus is known to have also studied light and vision, using correct geometry, but the insufficiently accurate 87° datum, Aristarchus concluded that the Sun was between 18 and 20 times farther away than the Moon. The implicit false solar parallax of slightly under 3° was used by astronomers up to and including Tycho Brahe, Aristarchus inequality Belief Perseverance Heath, Sir Thomas. Gomez, A. G. Aristarchos of Samos, the Polymath, online Galleries, History of Science Collections, University of Oklahoma Libraries High resolution images of works by Aristarchus of Samos in. jpg and. tiff format
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Heliocentrism
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Heliocentrism is the astronomical model in which the Earth and planets revolve around the Sun at the center of the Solar System. Historically, Heliocentrism was opposed to geocentrism, which placed the Earth at the center, in the following century, Johannes Kepler elaborated upon and expanded this model to include elliptical orbits, and Galileo Galilei presented supporting observations made using a telescope. With the observations of William Herschel, Friedrich Bessel, and others, astronomers realized that the sun, the Ptolemaic system was a sophisticated astronomical system that managed to calculate the positions for the planets to a fair degree of accuracy. However, he rejected the idea of a spinning earth as absurd as he believed it would create huge winds and his planetary hypotheses were sufficiently real that the distances of moon, sun, planets and stars could be determined by treating orbits celestial spheres as contiguous realities. This system postulated the existence of a counter-earth collinear with the Earth and central fire, the Sun revolved around the central fire once a year, and the stars were stationary. The Earth maintained the same face towards the central fire. Kepler gave an explanation of the Pythagoreans central fire as the Sun. Heraclides of Pontus said that the rotation of the Earth explained the apparent daily motion of the celestial sphere and it used to be thought that he believed Mercury and Venus to revolve around the Sun, which in turn revolves around the Earth. Macrobius Ambrosius Theodosius later described this as the Egyptian System, stating that it did not escape the skill of the Egyptians, the first person known to have proposed a heliocentric system, however, was Aristarchus of Samos. Like Eratosthenes, Aristarchus calculated the size of the Earth, and measured the size and distance of the Moon and Sun, from his estimates, he concluded that the Sun was six to seven times wider than the Earth and thus hundreds of times more voluminous. His writings on the system are lost, but some information is known from surviving descriptions and critical commentary by his contemporaries. This is the account as you have heard from astronomers. The stars are in fact much farther away than the distance that was assumed in ancient times. Archimedes says that Aristarchus made the stars distance larger, suggesting that he was answering the natural objection that Heliocentrism requires stellar parallactic oscillations and he apparently agreed to the point but placed the stars so distant as to make the parallactic motion invisibly minuscule. Thus Heliocentrism opened the way for realization that the universe was larger than the geocentrists taught, according to one of Plutarchs characters in the dialogue, the philosopher Cleanthes had held that Aristarchus should be charged with impiety for moving the hearth of the world. Since Plutarch mentions the followers of Aristarchus in passing, it is likely there were other astronomers in the Classical period who also espoused Heliocentrism. Seleucus adopted the system of Aristarchus and is said to have proved the heliocentric theory. He may have used trigonometric methods that were available in his time
15.
Scientific method
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The scientific method is a body of techniques for investigating phenomena, acquiring new knowledge, or correcting and integrating previous knowledge. To be termed scientific, a method of inquiry is commonly based on empirical or measurable evidence subject to specific principles of reasoning, experiments need to be designed to test hypotheses. The most important part of the method is the experiment. The scientific method is a process, which usually begins with observations about the natural world. Human beings are naturally inquisitive, so often come up with questions about things they see or hear. The best hypotheses lead to predictions that can be tested in various ways, in general, the strongest tests of hypotheses come from carefully controlled and replicated experiments that gather empirical data. Depending on how well the tests match the predictions, the hypothesis may require refinement. If a particular hypothesis becomes very well supported a theory may be developed. Although procedures vary from one field of inquiry to another, identifiable features are shared in common between them. The overall process of the method involves making conjectures, deriving predictions from them as logical consequences. A hypothesis is a conjecture, based on knowledge obtained while formulating the question, the hypothesis might be very specific or it might be broad. Scientists then test hypotheses by conducting experiments, the purpose of an experiment is to determine whether observations agree with or conflict with the predictions derived from a hypothesis. Experiments can take anywhere from a college lab to CERNs Large Hadron Collider. There are difficulties in a statement of method, however. Though the scientific method is presented as a fixed sequence of steps. Not all steps take place in scientific inquiry, and are not always in the same order. Some philosophers and scientists have argued there is no scientific method, such as Lee Smolin. Nola and Sankey remark that For some, the idea of a theory of scientific method is yester-years debate
16.
Experiment
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An experiment is a procedure carried out to support, refute, or validate a hypothesis. Experiments provide insight into cause-and-effect by demonstrating what outcome occurs when a particular factor is manipulated, experiments vary greatly in goal and scale, but always rely on repeatable procedure and logical analysis of the results. There also exists natural experimental studies, a child may carry out basic experiments to understand gravity, while teams of scientists may take years of systematic investigation to advance their understanding of a phenomenon. Experiments and other types of activities are very important to student learning in the science classroom. Experiments can raise test scores and help a student become more engaged and interested in the material they are learning, experiments can vary from personal and informal natural comparisons, to highly controlled. Uses of experiments vary considerably between the natural and human sciences, experiments typically include controls, which are designed to minimize the effects of variables other than the single independent variable. This increases the reliability of the results, often through a comparison between control measurements and the other measurements, scientific controls are a part of the scientific method. Ideally, all variables in an experiment are controlled and none are uncontrolled, in such an experiment, if all controls work as expected, it is possible to conclude that the experiment works as intended, and that results are due to the effect of the tested variable. In the scientific method, an experiment is a procedure that arbitrates between competing models or hypotheses. Researchers also use experimentation to test existing theories or new hypotheses to support or disprove them, an experiment usually tests a hypothesis, which is an expectation about how a particular process or phenomenon works. However, an experiment may also aim to answer a question, without a specific expectation about what the experiment reveals. If an experiment is conducted, the results usually either support or disprove the hypothesis. According to some philosophies of science, an experiment can never prove a hypothesis, on the other hand, an experiment that provides a counterexample can disprove a theory or hypothesis. An experiment must also control the possible confounding factors—any factors that would mar the accuracy or repeatability of the experiment or the ability to interpret the results, confounding is commonly eliminated through scientific controls and/or, in randomized experiments, through random assignment. In engineering and the sciences, experiments are a primary component of the scientific method. They are used to test theories and hypotheses about how physical processes work under particular conditions, typically, experiments in these fields focus on replication of identical procedures in hopes of producing identical results in each replication. In medicine and the sciences, the prevalence of experimental research varies widely across disciplines. In contrast to norms in the sciences, the focus is typically on the average treatment effect or another test statistic produced by the experiment
17.
Telescope
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A telescope is an optical instrument that aids in the observation of remote objects by collecting electromagnetic radiation. The first known practical telescopes were invented in the Netherlands at the beginning of the 1600s and they found use in both terrestrial applications and astronomy. Within a few decades, the telescope was invented, which used mirrors to collect. In the 20th century many new types of telescopes were invented, including radio telescopes in the 1930s, the word telescope now refers to a wide range of instruments capable of detecting different regions of the electromagnetic spectrum, and in some cases other types of detectors. The word telescope was coined in 1611 by the Greek mathematician Giovanni Demisiani for one of Galileo Galileis instruments presented at a banquet at the Accademia dei Lincei, in the Starry Messenger, Galileo had used the term perspicillum. The earliest recorded working telescopes were the telescopes that appeared in the Netherlands in 1608. Their development is credited to three individuals, Hans Lippershey and Zacharias Janssen, who were spectacle makers in Middelburg, Galileo heard about the Dutch telescope in June 1609, built his own within a month, and improved upon the design in the following year. Also in 1609, Thomas Harriot became the first person known to point a telescope skyward in order to make observations of a celestial object. The idea that the objective, or light-gathering element, could be a mirror instead of a lens was being investigated soon after the invention of the refracting telescope. The potential advantages of using parabolic mirrors—reduction of spherical aberration and no chromatic aberration—led to many proposed designs, in 1668, Isaac Newton built the first practical reflecting telescope, of a design which now bears his name, the Newtonian reflector. The invention of the lens in 1733 partially corrected color aberrations present in the simple lens and enabled the construction of shorter. The largest reflecting telescopes currently have objectives larger than 10 m, the 20th century also saw the development of telescopes that worked in a wide range of wavelengths from radio to gamma-rays. The first purpose built radio telescope went into operation in 1937, since then, a tremendous variety of complex astronomical instruments have been developed. The name telescope covers a range of instruments. Most detect electromagnetic radiation, but there are differences in how astronomers must go about collecting light in different frequency bands. The near-infrared can be collected much like light, however in the far-infrared and submillimetre range. For example, the James Clerk Maxwell Telescope observes from wavelengths from 3 μm to 2000 μm, on the other hand, the Spitzer Space Telescope, observing from about 3 μm to 180 μm uses a mirror. Also using reflecting optics, the Hubble Space Telescope with Wide Field Camera 3 can observe in the range from about 0.2 μm to 1.7 μm
18.
Vacuum pump
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A vacuum pump is a device that removes gas molecules from a sealed volume in order to leave behind a partial vacuum. The first vacuum pump was invented in 1650 by Otto von Guericke, and was preceded by the suction pump, the predecessor to the vacuum pump was the suction pump, which was known to the Romans. Dual-action suction pumps were found in the city of Pompeii, arabic engineer Al-Jazari also described suction pumps in the 13th century. He said that his model was a version of the siphons the Byzantines used to discharge the Greek fire. The suction pump later reappeared in Europe from the 15th century, by the 17th century, water pump designs had improved to the point that they produced measurable vacuums, but this was not immediately understood. What was known was that suction pumps could not pull water beyond a certain height,18 Florentine yards according to a measurement taken around 1635. This limit was a concern to irrigation projects, mine drainage, Galileo advertised the puzzle to other scientists, including Gaspar Berti who replicated it by building the first water barometer in Rome in 1639. Bertis barometer produced a vacuum above the column, but he could not explain it. The breakthrough was made by Evangelista Torricelli in 1643, building upon Galileos notes, he built the first mercury barometer and wrote a convincing argument that the space at the top was a vacuum. Robert Boyle improved Guerickes design and conducted experiments on the properties of vacuum, robert Hooke also helped Boyle produce an air pump which helped to produce the vacuum. The study of vacuum then lapsed until 1855, when Heinrich Geissler invented the mercury displacement pump, a number of electrical properties become observable at this vacuum level, and this renewed interest in vacuum. This, in turn, led to the development of the vacuum tube, in the 19th century, Nikola Tesla designed an apparatus that contains a Sprengel pump to create a high degree of exhaustion. Momentum transfer pumps, also called molecular pumps, use high speed jets of dense fluid or high speed rotating blades to knock gas molecules out of the chamber, entrapment pumps capture gases in a solid or adsorbed state. This includes cryopumps, getters, and ion pumps, positive displacement pumps are the most effective for low vacuums. Momentum transfer pumps in conjunction with one or two positive displacement pumps are the most common used to achieve high vacuums. In this configuration the positive displacement pump serves two purposes, second the positive displacement pump backs up the momentum transfer pump by evacuating to low vacuum the accumulation of displaced molecules in the high vacuum pump. Entrapment pumps can be added to reach ultrahigh vacuums, but they require periodic regeneration of the surfaces that trap air molecules or ions, due to this requirement their available operational time can be unacceptably short in low and high vacuums, thus limiting their use to ultrahigh vacuums. A partial vacuum may be generated by increasing the volume of a container, to continue evacuating a chamber indefinitely without requiring infinite growth, a compartment of the vacuum can be repeatedly closed off, exhausted, and expanded again
19.
Petrus Apianus
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Petrus Apianus, also known as Peter Apian, was a German humanist, known for his works in mathematics, astronomy and cartography. The lunar crater Apianus and minor planet 19139 Apian are named in his honour and he was born as Peter Bienewitz in Leisnig in Saxony, his father was a shoemaker. The family was well off, belonging to the middle-class citizenry of Leisnig. Apianus was educated at the Latin school in Rochlitz, from 1516 to 1519 he studied at the University of Leipzig, during this time, he Latinized his name to Apianus. When the plague broke out in Vienna in 1521, he completed his studies with a B. A. and moved to Regensburg and he married the daughter of a councilman of Landshut, Katharina Mosner, in 1526. They would have 14 children together, five girls and nine sons, in 1527, Peter Apian was called to the University of Ingolstadt as a mathematician and printer. Among the first books he printed were the writings of Johann Eck, later, his print shop soon became well known for its high-quality editions of geographic and cartographic works. Through his work, Apian became a favourite of emperor Charles V. Charles had praised his work at the Imperial Diet of 1530, in 1535, the emperor made Apian an armiger, i. e. granted him the right to display a coat of arms. All this furthered Apians reputation as an eminent scientist, Apian is also remembered for publishing the only known depiction of the Bedouin constellations in 1533. On this map Ursa Minor is an old woman and three maidens, Draco is four camels and Cepheus was illustrated as a shepherd with sheep, despite many calls from other universities, including Leipzig, Padua, Tübingen, and Vienna, Apian remained in Ingolstadt until his death. Although he neglected his duties, the university evidently was proud to host such an esteemed scientist. Apians work included in mathematics—in 1527 he published a variation of Pascals triangle, in 1531, he observed a comet and discovered that a comets tail always point away from the sun. Apian was followed by his son Philipp, who, in addition to his own research, ein newe und wolgegründete underweisung aller Kauffmanns Rechnung in dreyen Büchern, mit schönen Regeln und fragstücken begriffen, Ingolstadt 1527. A handbook of commercial arithmetic, depicted in the painting The Ambassadors by Hans Holbein the Younger, Cosmographiae introductio, cum quibusdam Geometriae ac Astronomiae principiis ad eam rem necessariis, Ingolstadt 1529. Ein kurtzer bericht der Observation unnd urtels des jüngst erschinnen Cometen, a scientific book on astronomical instruments in German. ^1 Whether Apian ever received the money is uncertain, in any case he wrote a letter to the emperor in 1549 asking him to finally pay the promised sum. Röttel, K. Peter Apian, Astronomie, Kosmographie und Mathematik am Beginn der Neuzeit, Polygon-Verlag 1995, Peter and Philipp Apian, in German. Volume 1, Vom Astrolab zum mathematischen Besteck, oConnor, John J. Robertson, Edmund F. Petrus Apianus, MacTutor History of Mathematics archive, University of St Andrews
20.
Meteorite
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When the object enters the atmosphere, various factors like friction, pressure, and chemical interactions with the atmospheric gases cause it to heat up and radiate that energy. It then becomes a meteor and forms a fireball, also known as a shooting/falling star, meteorites that survive atmospheric entry and impact vary greatly in size. For geologists, a bolide is a large enough to create a crater. Meteorites that are recovered after being observed as they transit the atmosphere or impact the Earth are called meteorite falls, all others are known as meteorite finds. As of April 2016, there were about 1,140 witnessed falls that have specimens in the worlds collections, there are more than 38,660 well-documented meteorite finds. Modern classification schemes divide meteorites into groups according to their structure, chemical and isotopic composition, meteorites smaller than 2 mm are classified as micrometeorites. Extraterrestrial meteorites are such objects that have impacted other celestial bodies and they have been found on the Moon and Mars. Meteorites are always named for the places they were found, usually a town or geographic feature. In cases where many meteorites were found in one place, the name may be followed by a number or letter, the name designated by the Meteoritical Society is used by scientists, catalogers, and most collectors. Most meteoroids disintegrate when entering the Earths atmosphere, usually, five to ten a year are observed to fall and are subsequently recovered and made known to scientists. Few meteorites are large enough to create large impact craters, instead, they typically arrive at the surface at their terminal velocity and, at most, create a small pit. Large meteoroids may strike the ground with a significant fraction of their escape velocity, the kind of crater will depend on the size, composition, degree of fragmentation, and incoming angle of the impactor. The force of such collisions has the potential to cause widespread destruction, the most frequent hypervelocity cratering events on the Earth are caused by iron meteoroids, which are most easily able to transit the atmosphere intact. In contrast, even relatively large stony or icy bodies like small comets or asteroids, up to millions of tons, are disrupted in the atmosphere, and do not make impact craters. Although such disruption events are uncommon, they can cause a concussion to occur. Very large stony objects, hundreds of meters in diameter or more, weighing tens of millions of tons or more, can reach the surface and cause large craters, such events are generally so energetic that the impactor is completely destroyed, leaving no meteorites. Several phenomena are well documented during witnessed meteorite falls too small to produce hypervelocity craters, various colors have been reported, including yellow, green, and red. Flashes and bursts of light can occur as the object breaks up, explosions, detonations, and rumblings are often heard during meteorite falls, which can be caused by sonic booms as well as shock waves resulting from major fragmentation events
21.
Comet
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A comet is an icy small Solar System body that, when passing close to the Sun, warms and begins to evolve gasses, a process called outgassing. This produces an atmosphere or coma, and sometimes also a tail. These phenomena are due to the effects of radiation and the solar wind acting upon the nucleus of the comet. Comet nuclei range from a few hundred metres to tens of kilometres across and are composed of collections of ice, dust. The coma may be up to 15 times the Earths diameter, if sufficiently bright, a comet may be seen from the Earth without the aid of a telescope and may subtend an arc of 30° across the sky. Comets have been observed and recorded since ancient times by many cultures, Comets usually have highly eccentric elliptical orbits, and they have a wide range of orbital periods, ranging from several years to potentially several millions of years. Short-period comets originate in the Kuiper belt or its associated scattered disc, long-period comets are thought to originate in the Oort cloud, a spherical cloud of icy bodies extending from outside the Kuiper belt to halfway to the nearest star. Long-period comets are set in motion towards the Sun from the Oort cloud by gravitational perturbations caused by passing stars, hyperbolic comets may pass once through the inner Solar System before being flung to interstellar space. The appearance of a comet is called an apparition, Comets are distinguished from asteroids by the presence of an extended, gravitationally unbound atmosphere surrounding their central nucleus. This atmosphere has parts termed the coma and the tail, however, extinct comets that have passed close to the Sun many times have lost nearly all of their volatile ices and dust and may come to resemble small asteroids. Asteroids are thought to have a different origin from comets, having formed inside the orbit of Jupiter rather than in the outer Solar System, the discovery of main-belt comets and active centaur minor planets has blurred the distinction between asteroids and comets. As of November 2014 there are 5,253 known comets, however, this represents only a tiny fraction of the total potential comet population, as the reservoir of comet-like bodies in the outer Solar System is estimated to be one trillion. Roughly one comet per year is visible to the eye, though many of those are faint. Particularly bright examples are called Great Comets, the word comet derives from the Old English cometa from the Latin comēta or comētēs. That, in turn, is a latinisation of the Greek κομήτης, Κομήτης was derived from κομᾶν, which was itself derived from κόμη and was used to mean the tail of a comet. The astronomical symbol for comets is ☄, consisting of a disc with three hairlike extensions. The solid, core structure of a comet is known as the nucleus, cometary nuclei are composed of an amalgamation of rock, dust, water ice, and frozen gases such as carbon dioxide, carbon monoxide, methane, and ammonia. As such, they are described as dirty snowballs after Fred Whipples model
22.
Planet symbols
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A planet symbol is a graphical symbol either in astrology or astronomy representing either a classical planet or one of the eight modern planets. In alchemy, the symbols are used to represent the metals which are associated with the respective planets. The use of symbols is based in ancient Greco-Roman tradition. In certain cases where planetary symbols might be used, such as in the headings of tables, the planet symbols are encoded by Unicode in the Miscellaneous Symbols block. The written symbols for Mercury, Venus, Jupiter, and Saturn have been traced to forms found in late Greek papyri, early forms are also found in medieval Byzantine codices in which many ancient horoscopes were preserved. These cross-marks first appear in the late 15th or early 16th century, according to Maunder, the addition of crosses appears to be an attempt to give a savour of Christianity to the symbols of the old pagan gods. Earth is not, of course, one of the classical planets and its status as planet is a consequence of the development of heliocentrism. Alternatively, there is the globus cruciger, now most commonly used as planetary symbol, the globus cruciger symbol is also used as an alchemical symbol of antimony. Uranus, The symbols for Uranus were created shortly after its discovery in 1781, one symbol, invented by J. G. This symbol also combines the symbols of Mars and the Sun because in Greek Mythology, Uranus represented heaven, and represents the power of Mars spear. Another symbol, was suggested by Lalande in 1784, in a letter to Herschel, Lalande described it as un globe surmonté par la première lettre de votre nom. Neptune, Several symbols were proposed for Neptune to accompany the suggested names for the planet. In October, he sought to name the planet Leverrier, after himself, and he had support in this from the observatory director, François Arago. However, this met with stiff resistance outside France. French almanacs quickly reintroduced the name Herschel for Uranus, after that planets discoverer Sir William Herschel, professor James Pillans of the University of Edinburgh defended the name Janus for the new planet, and proposed a key for its symbol. Meanwhile, Struve presented the name Neptune on December 29,1846, in August 1847, the Bureau des Longitudes announced its decision to follow prevailing astronomical practice and adopt the choice of Neptune, with Arago refraining from participating in this decision. Pluto was also considered a planet from its discovery in 1930 until its re-classification as a planet in 2007. The symbol used for Pluto was a ligature of the letters P and L
23.
Firmament
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In Biblical cosmology, the firmament is the structure above the atmosphere, conceived as a vast solid dome. According to the Genesis creation narrative, God created the firmament to separate the waters above the earth from the waters below the earth, the word is anglicized from Latin firmamentum, which appears in the Vulgate, a late fourth-century Latin translation of the Bible. The firmament is described in Genesis 1, 6–8 in the Genesis creation narrative, Then God said, “Let there be a firmament in the midst of the waters, and let it divide the waters from the waters. ”Thus God made the firmament, and divided the waters which were under the firmament from the waters which were above the firmament, and it was so. And God called the firmament Heaven, so the evening and the morning were the second day. The word firmament is first recorded in a Middle English narrative based on scripture dated 1250 and it later appeared in the King James Bible. The word is anglicised from Latin firmamentum, used in the Vulgate and this in turn is derived from the Latin root firmus, a cognate with firm. The word is a Latinization of the Greek stereōma, which appears in the Septuagint, the word firmament is used to translate rāqîa‘, a word used in Biblical Hebrew. It is derived from the root raqqə‘, meaning to beat or spread out, like most ancient peoples, the Hebrews believed the sky was a solid dome with the Sun, Moon, planets and stars embedded in it. According to The Jewish Encyclopedia, The Hebrews regarded the earth as a plain or a hill figured like a hemisphere, over this is arched the solid vault of heaven. To this vault are fastened the lights, the stars, so slight is this elevation that birds may rise to it and fly along its expanse. Augustine wrote that too much learning had been expended on the nature of the firmament and we may understand this name as given to indicate not it is motionless but that it is solid. Saint Basil argued for a fluid firmament, according to St. Thomas Aquinas, the firmament had a solid nature and stood above a region of fire, wherein all vapor must be consumed. The Copernican Revolution of the 16th century led to reconsideration of these matters, in 1554, John Calvin proposed that firmament be interpreted as clouds. He who would learn astronomy and other arts, let him go elsewhere. As it became a theologian, had to respect us rather than the stars, calvins doctrine of accommodation allowed Protestants to accept the findings of science without rejecting the authority of scripture. The Greeks and Stoics adopted a model of celestial spheres after the discovery of the spherical Earth in the 4th to 3rd centuries BC, the Medieval Scholastics adopted a cosmology that fused the ideas of the Greek philosophers Aristotle and Ptolemy. This cosmology involved celestial orbs, nested concentrically inside one another, the outermost orb contained the stars and the term firmament was then transferred to this orb. There were seven inner orbs for the seven wanderers of the sky, even Copernicus heliocentric model included an outer sphere that held the stars
24.
Constellation
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A constellation is formally defined as a region of the celestial sphere, with boundaries laid down by the International Astronomical Union. The constellation areas mostly had their origins in Western-traditional patterns of stars from which the constellations take their names, in 1922, the International Astronomical Union officially recognized the 88 modern constellations, which cover the entire sky. They began as the 48 classical Greek constellations laid down by Ptolemy in the Almagest, Constellations in the far southern sky are late 16th- and mid 18th-century constructions. 12 of the 88 constellations compose the zodiac signs, though the positions of the constellations only loosely match the dates assigned to them in astrology. The term constellation can refer to the stars within the boundaries of that constellation. Notable groupings of stars that do not form a constellation are called asterisms, when astronomers say something is “in” a given constellation they mean it is within those official boundaries. Any given point in a coordinate system can unambiguously be assigned to a single constellation. Many astronomical naming systems give the constellation in which an object is found along with a designation in order to convey a rough idea in which part of the sky it is located. For example, the Flamsteed designation for bright stars consists of a number, the word constellation seems to come from the Late Latin term cōnstellātiō, which can be translated as set of stars, and came into use in English during the 14th century. It also denotes 88 named groups of stars in the shape of stellar-patterns, the Ancient Greek word for constellation was ἄστρον. Colloquial usage does not draw a distinction between constellation in the sense of an asterism and constellation in the sense of an area surrounding an asterism. The modern system of constellations used in astronomy employs the latter concept, the term circumpolar constellation is used for any constellation that, from a particular latitude on Earth, never sets below the horizon. From the North Pole or South Pole, all constellations south or north of the equator are circumpolar constellations. In the equatorial or temperate latitudes, the term equatorial constellation has sometimes been used for constellations that lie to the opposite the circumpolar constellations. They generally include all constellations that intersect the celestial equator or part of the zodiac, usually the only thing the stars in a constellation have in common is that they appear near each other in the sky when viewed from the Earth. In galactic space, the stars of a constellation usually lie at a variety of distances, since stars also travel on their own orbits through the Milky Way, the star patterns of the constellations change slowly over time. After tens to hundreds of thousands of years, their familiar outlines will become unrecognisable, the terms chosen for the constellation themselves, together with the appearance of a constellation, may reveal where and when its constellation makers lived. The earliest direct evidence for the constellations comes from inscribed stones and it seems that the bulk of the Mesopotamian constellations were created within a relatively short interval from around 1300 to 1000 BC
25.
Axial precession
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In astronomy, axial precession is a gravity-induced, slow, and continuous change in the orientation of an astronomical bodys rotational axis. The term precession typically refers only to this largest part of the motion, other changes in the alignment of Earths axis—nutation and this term is still used in non-technical discussions, that is, when detailed mathematics are absent. Their combination was named general precession, instead of precession of the equinoxes, lunisolar precession is caused by the gravitational forces of the Moon and Sun on Earths equatorial bulge, causing Earths axis to move with respect to inertial space. Lunisolar precession is about 500 times greater than planetary precession, many references to the old terms exist in publications predating the change. Etymologically, precession and procession are both terms that relate to motion, Precession is derived from the Latin praecedere, to precede, to come before or earlier), while procession is derived from the Latin procedere, to march forward, to advance). Generally the term procession is used to describe a group of objects moving forward, the stars viewed from Earth are seen to proceed in a procession from east to west daily, due to the Earth’s diurnal motion, and yearly, due to the Earth’s revolution around the Sun. At the same time the stars can be observed to anticipate slightly such motion, at the rate of approximately 50 arc seconds per year, in describing this motion astronomers generally have shortened the term to simply precession. This issue is further obfuscated by the fact that many astronomers are physicists or astrophysicists, the precession of the Earths axis has a number of observable effects. First, the positions of the south and north celestial poles appear to move in circles against the backdrop of stars. Thus, while today the star Polaris lies approximately at the celestial pole, this will change over time. In approximately 3200 years, the star Gamma Cephei in the Cepheus constellation will succeed Polaris for this position, the south celestial pole currently lacks a bright star to mark its position, but over time precession also will cause bright stars to become south stars. As the celestial poles shift, there is a gradual shift in the apparent orientation of the whole star field. Secondly, the position of the Earth in its orbit around the Sun at the solstices, equinoxes, or other time defined relative to the seasons, slowly changes. For example, suppose that the Earths orbital position is marked at the summer solstice, in other words, the solstice occurred a little earlier in the orbit. Thus, the year, measuring the cycle of seasons, is about 20 minutes shorter than the sidereal year. For further details, see Changing pole stars and Polar shift and equinoxes shift, according to Ptolemys Almagest, Hipparchus measured the longitude of Spica and other bright stars. Comparing his measurements with data from his predecessors, Timocharis and Aristillus and he also compared the lengths of the tropical year and the sidereal year, and found a slight discrepancy. Virtually all of the writings of Hipparchus are lost, including his work on precession and they are mentioned by Ptolemy, who explains precession as the rotation of the celestial sphere around a motionless Earth
26.
Prime mover theory
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The unmoved mover or prime mover is a monotheistic concept advanced by Aristotle, a polytheist, as a primary cause or mover of all the motion in the universe. As is implicit in the name, the unmoved mover moves other things, in Book 12 of his Metaphysics, Aristotle describes the unmoved mover as being perfectly beautiful, indivisible, and contemplating only the perfect contemplation, itself contemplating. He equates this concept also with the active intellect, st. Thomas Aquinas, for example, elaborated on the unmoved mover in the Quinque viae. In the Physics Aristotle finds surprising difficulties explaining even commonplace change, Aristotles first philosophy, or Metaphysics, develops his peculiar theology of the prime mover, as πρῶτον κινοῦν ἀκίνητον, an independent divine eternal unchanging immaterial substance. While the number of spheres in the model itself was subject to change, Aristotles account of aether, as such, it would be physically impossible for them to move material objects of any size by pushing, pulling or collision. Their influence on lesser beings is purely the result of an aspiration or desire, the first heaven, the outmost sphere of fixed stars, is moved by a desire to emulate the prime mover, in relation to whom, the subordinate movers suffer an accidental dependency. Many of Aristotles contemporaries complained that oblivious, powerless gods are unsatisfactory, nonetheless, it was a life which Aristotle enthusiastically endorsed as one most enviable and perfect, the unembellished basis of theology. As the whole of nature depends on the inspiration of the unmoved movers. It is through the action of the Sun upon the terrestrial spheres. The intellect, nous, or whatever else it be that is thought to rule and lead us by nature and it is also the most sustainable, pleasant, self-sufficient activity, something which is aimed at for its own sake. This aim is not strictly human, to achieve it means to live in accordance not with mortal thoughts, according to Aristotle, contemplation is the only type of happy activity which it would not be ridiculous to imagine the gods having. In Aristotles psychology and biology, the intellect is the soul and he argues that in the beginning, if the cosmos had come to be, its first motion would lack an antecedent state, and as Parmenides said, nothing comes from nothing. The Cosmological argument, later attributed to Aristotle, thereby draws the conclusion that God exists, however, if the cosmos had a beginning, Aristotle argued, it would require an efficient first cause, a notion that Aristotle took to demonstrate a critical flaw. The purpose of Aristotles cosmological argument, that at least one eternal unmoved mover must exist, is to support everyday change, of things that exist, substances are the first. But if substances can, then all things can perish. and yet, time, now, the only continuous change is that of place, and the only continuous change of place is circular motion. Therefore, there must be a circular motion and this confirmed by the fixed stars which are moved by the eternal actual substance substance thats purely actual. Even though the foregoing might have suggested that generation of substances is fundamental for all the kinds of changes. Aristotle argues at the opening of Physics bk.8 that motion and change in the universe can have no beginning, with this argument Aristotle can establish an eternal chain of motions and refute those who hold that there could have been a previous stationary state of the universe
27.
Unmoved mover
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The unmoved mover or prime mover is a monotheistic concept advanced by Aristotle, a polytheist, as a primary cause or mover of all the motion in the universe. As is implicit in the name, the unmoved mover moves other things, in Book 12 of his Metaphysics, Aristotle describes the unmoved mover as being perfectly beautiful, indivisible, and contemplating only the perfect contemplation, itself contemplating. He equates this concept also with the active intellect, st. Thomas Aquinas, for example, elaborated on the unmoved mover in the Quinque viae. In the Physics Aristotle finds surprising difficulties explaining even commonplace change, Aristotles first philosophy, or Metaphysics, develops his peculiar theology of the prime mover, as πρῶτον κινοῦν ἀκίνητον, an independent divine eternal unchanging immaterial substance. While the number of spheres in the model itself was subject to change, Aristotles account of aether, as such, it would be physically impossible for them to move material objects of any size by pushing, pulling or collision. Their influence on lesser beings is purely the result of an aspiration or desire, the first heaven, the outmost sphere of fixed stars, is moved by a desire to emulate the prime mover, in relation to whom, the subordinate movers suffer an accidental dependency. Many of Aristotles contemporaries complained that oblivious, powerless gods are unsatisfactory, nonetheless, it was a life which Aristotle enthusiastically endorsed as one most enviable and perfect, the unembellished basis of theology. As the whole of nature depends on the inspiration of the unmoved movers. It is through the action of the Sun upon the terrestrial spheres. The intellect, nous, or whatever else it be that is thought to rule and lead us by nature and it is also the most sustainable, pleasant, self-sufficient activity, something which is aimed at for its own sake. This aim is not strictly human, to achieve it means to live in accordance not with mortal thoughts, according to Aristotle, contemplation is the only type of happy activity which it would not be ridiculous to imagine the gods having. In Aristotles psychology and biology, the intellect is the soul and he argues that in the beginning, if the cosmos had come to be, its first motion would lack an antecedent state, and as Parmenides said, nothing comes from nothing. The Cosmological argument, later attributed to Aristotle, thereby draws the conclusion that God exists, however, if the cosmos had a beginning, Aristotle argued, it would require an efficient first cause, a notion that Aristotle took to demonstrate a critical flaw. The purpose of Aristotles cosmological argument, that at least one eternal unmoved mover must exist, is to support everyday change, of things that exist, substances are the first. But if substances can, then all things can perish. and yet, time, now, the only continuous change is that of place, and the only continuous change of place is circular motion. Therefore, there must be a circular motion and this confirmed by the fixed stars which are moved by the eternal actual substance substance thats purely actual. Even though the foregoing might have suggested that generation of substances is fundamental for all the kinds of changes. Aristotle argues at the opening of Physics bk.8 that motion and change in the universe can have no beginning, with this argument Aristotle can establish an eternal chain of motions and refute those who hold that there could have been a previous stationary state of the universe
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Celestial sphere
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In astronomy and navigation, the celestial sphere is an imaginary sphere of arbitrarily large radius, concentric with Earth. All objects in the sky can be thought of as projected upon the inside surface of the celestial sphere. The celestial sphere is a tool for spherical astronomy, allowing observers to plot positions of objects in the sky when their distances are unknown or unimportant. Because astronomical objects are at such distances, casual observation of the sky offers no information on the actual distances. All objects seem equally far away, as if fixed to the inside of a sphere of large but unknown radius, which rotates from east to west overhead while underfoot, the celestial sphere can be considered to be infinite in radius. This means any point within it, including that occupied by the observer, all parallel planes will seem to intersect the sphere in a coincident great circle. On an infinite-radius celestial sphere, all observers see the things in the same direction. For some objects, this is over-simplified, objects which are relatively near to the observer will seem to change position against the distant celestial sphere if the observer moves far enough, say, from one side of the Earth to the other. This effect, known as parallax, can be represented as an offset from a mean position. The celestial sphere can be considered to be centered at the Earths center, the Suns center, or any convenient location. Individual observers can work out their own small offsets from the mean positions, in many cases in astronomy, the offsets are insignificant. The celestial sphere can thus be thought of as a kind of astronomical shorthand, for many rough uses, this position, as seen from the Earths center, is adequate. This greatly abbreviates the amount of detail necessary in such almanacs and these concepts are important for understanding celestial coordinate systems – frameworks for measuring the positions of objects in the sky. Certain reference lines and planes on Earth, when projected onto the celestial sphere and these include the Earths equator, axis, and the Earths orbit. At their intersections with the sphere, these form the celestial equator, the north and south celestial poles. As the celestial sphere is considered infinite in radius, all observers see the celestial equator, celestial poles, from these bases, directions toward objects in the sky can be quantified by constructing celestial coordinate systems. Similar to terrestrial longitude and latitude, the coordinate system specifies positions relative to the celestial equator and celestial poles. The ecliptic coordinate system specifies positions relative to the Earths orbit, besides the equatorial and ecliptic systems, some other celestial coordinate systems, such as the galactic coordinate system, are more appropriate for particular purposes
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Classical element
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Ancient cultures in Egypt, Babylonia, Japan, Tibet, and India had similar lists, sometimes referring in local languages to air as wind and the fifth element as void. The Chinese Wu Xing system lists Wood, Fire, Earth, Metal and these different cultures and even individual philosophers had widely varying explanations concerning their attributes and how they related to observable phenomena as well as cosmology. Sometimes these theories overlapped with mythology and were personified in deities, some of these interpretations included atomism but other interpretations considered the elements to be divisible into infinitely small pieces without changing their nature. Centuries of empirical investigation have proven that all the ancient systems were incorrect explanations of the physical world. It is now known that atomic theory is an explanation, and that atoms can be classified into more than a hundred chemical elements such as oxygen, iron. These elements form chemical compounds and mixtures, and under different temperatures and pressures, the concept of the five elements formed a basis of analysis in both Hinduism and Buddhism. In Hinduism, particularly in a context, the four states-of-matter describe matter. Similar lists existed in ancient China and Japan, in Buddhism the four great elements, to which two others are sometimes added, are not viewed as substances, but as categories of sensory experience. A Greek text called the Kore Kosmou ascribed to Hermes Trismegistus, names the four fire, water, air. And, on the contrary, again some are made enemies of fire, and some of water, some of earth, and some of air, and some of two of them, and some of three, and some of all. For instance, son, the locust and all flies flee fire, the eagle and the hawk and all high-flying birds flee water, fish, air and earth, the snake avoids the open air. Not that some of the animals as well do not love fire, for instance salamanders and it is because one or another of the elements doth form their bodies outer envelope. Each soul, accordingly, while it is in its body is weighted and constricted by these four. According to Galen, these elements were used by Hippocrates in describing the body with an association with the four humours, yellow bile, black bile, blood. Medical care was flexible and primarily about helping the patient stay in or return to his/her own personal natural balanced state. In other Babylonian texts these phenomena are considered independent of their association with deities, though they are not treated as the component elements of the universe, the five elements are associated with the five senses, and act as the gross medium for the experience of sensations. The basest element, earth, created using all the elements, can be perceived by all five senses – hearing, touch, sight, taste. The next higher element, water, has no odor but can be heard, felt, seen, next comes fire, which can be heard, felt and seen
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Celestial spheres
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The celestial spheres, or celestial orbs, were the fundamental entities of the cosmological models developed by Plato, Eudoxus, Aristotle, Ptolemy, Copernicus and others. Since it was believed that the stars did not change their positions relative to one another. In modern thought, the orbits of the planets are viewed as the paths of those planets through mostly empty space, when scholars applied Ptolemys epicycles, they presumed that each planetary sphere was exactly thick enough to accommodate them. In Greek antiquity the ideas of celestial spheres and rings first appeared in the cosmology of Anaximander in the early 6th century BC, all these wheel rims had originally been formed out of an original sphere of fire wholly encompassing the Earth, which had disintegrated into many individual rings. Hence, in Anaximanderss cosmogony, in the beginning was the sphere, out of which celestial rings were formed, as viewed from the Earth, the ring of the Sun was highest, that of the Moon was lower, and the sphere of the stars was lowest. Following Anaximander, his pupil Anaximenes held that the stars, Sun, Moon, and planets are all made of fire. But whilst the stars are fastened on a crystal sphere like nails or studs, the Sun, Moon, and planets. And unlike Anaximander, he relegated the fixed stars to the region most distant from the Earth, after Anaximenes, Pythagoras, Xenophanes and Parmenides all held that the universe was spherical. And much later in the fourth century BC Platos Timaeus proposed that the body of the cosmos was made in the most perfect and uniform shape, but it posited that the planets were spherical bodies set in rotating bands or rings rather than wheel rims as in Anaximanders cosmology. Each planet is attached to the innermost of its own set of spheres. In his Metaphysics, Aristotle developed a cosmology of spheres. Aristotle considers that these spheres are made of a fifth element. Each of these concentric spheres is moved by its own god—an unchanging divine unmoved mover, by using eccentrics and epicycles, his geometrical model achieved greater mathematical detail and predictive accuracy than had been exhibited by earlier concentric spherical models of the cosmos. In Ptolemys physical model, each planet is contained in two or more spheres, but in Book 2 of his Planetary Hypotheses Ptolemy depicted thick circular slices rather than spheres as in its Book 1. The planetary spheres were arranged outwards from the spherical, stationary Earth at the centre of the universe in order, the spheres of the Moon, Mercury, Venus, Sun, Mars, Jupiter. In more detailed models the seven planetary spheres contained other secondary spheres within them, in antiquity the order of the lower planets was not universally agreed. Plato and his followers ordered them Moon, Sun, Mercury, Venus, a series of astronomers, beginning with the Muslim astronomer al-Farghānī, used the Ptolemaic model of nesting spheres to compute distances to the stars and planetary spheres. Al-Farghānīs distance to the stars was 20,110 Earth radii which, on the assumption that the radius of the Earth was 3,250 miles, came to 65,357,500 miles
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Earth (classical element)
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Earth is one of the classical elements, in some systems numbering four along with air, fire, and water. Earth is one of the four elements in ancient Greek philosophy. It was commonly associated with qualities of heaviness, matter and the terrestrial world, due to the hero cults, and chthonic underworld deities, the element of earth is also associated with the sensual aspects of both life and death in later occultism. Empedocles of Acragas proposed four archai by which to understand the cosmos, fire, air, water, plato believed the elements were geometric forms and he assigned the cube to the element of earth in his dialogue Timaeus. Aristotle, believed earth was the heaviest element, and his theory of natural place suggested that any earth–laden substances, would fall quickly, straight down, in ancient Greek medicine, each of the four humours became associated with an element. Black bile was the humor identified with earth, since both were cold and dry, in alchemy, earth was believed to be primarily dry, and secondarily cold. Beyond those classical attributes, the chemical substance salt, was associated with earth and its symbol was a downward-pointing triangle. Prithvi is the Hindu earth and mother goddess, according to one such tradition, she is the personification of the Earth itself, according to another, its actual mother, being Prithvi Tattwa, the essence of the element earth. As Prithvi Mata, or Mother Earth, she contrasts with Dyaus Pita, in the Rigveda, earth and sky are frequently addressed as a duality, often indicated by the idea of two complementary half-shells. In addition, the element Earth is associated with Budha or Mercury who represents communication, business, mathematics, people born under the astrological signs of Taurus, Virgo and Capricorn are thought to have dominant earth personalities. Earth and the other Greek classical elements were incorporated into the Golden Dawn system, zelator is the elemental grade attributed to earth, this grade is also attributed to the Qabbalistic sphere Malkuth. The elemental weapon of earth is the Pentacle, each of the elements has several associated spiritual beings. The archangel of earth is Uriel, the angel is Phorlakh, the ruler is Kerub, the king is Ghob, and the earth elementals are called gnomes. Earth is considered to be passive, it is represented by the symbol for Taurus, many of these associations have since spread throughout the occult community. It is sometimes represented by its Tattva or by a downward pointing triangle with a line through it. Earth is one of the five elements appear in most Wiccan and Pagan traditions. Wicca in particular was influenced by the Golden Dawn system of magic, and Aleister Crowleys mysticism which was in turn inspired by the Golden Dawn. In East Asia, metal is seen as the equivalent of earth and is represented by the White Tiger, known as 白虎 in Chinese, Byakko in Japanese, Bạch Hổ in Vietnamese
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Air (classical element)
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Air is often seen as a universal power or pure substance. Its fundamental importance to life can be seen in such as aspire, inspire, perspire and spirit. Air is one of the four elements in ancient Greek philosophy. According to Plato, it is associated with the octahedron, air is considered to be hot and wet. The ancient Greeks used two words for air, aer meant the dim lower atmosphere, and aether meant the bright upper atmosphere above the clouds. Plato, for instance writes that So it is air, there is the brightest variety which we call aether, the muddiest which we call mist and darkness. Among the early Greek Pre-Socratic philosophers, Anaximenes named air as the arche, aristophanes parodied such teachings in his play The Clouds by putting a prayer to air in the mouth of Socrates. Air was one of many proposed by the Pre-socratics, most of whom tried to reduce all things to a single substance. However, Empedocles of Acragas selected four archai for his four roots, Air, fire, water, Ancient and modern opinions differ as to whether he identified air by the divine name Hera, Aidoneus or even Zeus. Empedocles’ roots became the four elements of Greek philosophy. Plato took over the four elements of Empedocles, in the Timaeus, his major cosmological dialogue, the Platonic solid associated with air is the octahedron which is formed from eight equilateral triangles. This places air between fire and water which Plato regarded as appropriate because it is intermediate in its mobility, sharpness and he also said of air that its minuscule components are so smooth that one can barely feel them. Platos student Aristotle developed a different explanation for the elements based on pairs of qualities, the four elements were arranged concentrically around the center of the universe to form the sublunary sphere. According to Aristotle, air is hot and wet and occupies a place between fire and water among the elemental spheres. Aristotle definitively separated air from aether, for him, aether was an unchanging, almost divine substance that was found only in the heavens, where it formed celestial spheres. In ancient Greek medicine, each of the four humours became associated with an element, blood was the humor identified with air, since both were hot and wet. The alchemical symbol for air is a triangle, bisected by a horizontal line. In Hinduism, Vayu, also known as Vāta वात, Pavana पवन, or Prāna, is a deity, who is the father of Bhima
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Fire (classical element)
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Fire has been an important part of all cultures and religions from pre-history to modern day and was vital to the development of civilization. It has been regarded in many different contexts throughout history, Fire is one of the four classical elements in ancient Greek philosophy and science. It was commonly associated with the qualities of energy, assertiveness, in one Greek myth, Prometheus stole fire from the gods to protect the otherwise helpless humans, but was punished for this charity. Fire was one of many proposed by the Pre-socratics, most of whom sought to reduce the cosmos, or its creation. Heraclitus considered fire to be the most fundamental of all elements and he believed fire gave rise to the other three elements, All things are an interchange for fire, and fire for all things, just like goods for gold and gold for goods. He had a reputation for obscure philosophical principles and for speaking in riddles and this is a concept that anticipates both the four classical elements of Empedocles and Aristotles transmutation of the four elements into one another. This world, which is the same for all, no one of gods or men has made, but it always was and will be, an ever-living fire, with measures of it kindling, and measures going out. Heraclitus regarded the soul as being a mixture of fire and water, with fire being the noble part. He believed the goal of the soul is to be rid of water and become pure fire and he was known as the weeping philosopher and died of hydropsy, a swelling due to abnormal accumulation of fluid beneath the skin. However, Empedocles of Acragas, is best known for having selected all elements as his archai and by the time of Plato, the four Empedoclian elements were well established. This also makes fire the element with the smallest number of sides, and Plato regarded it as appropriate for the heat of fire, which he felt is sharp and stabbing. Fire the hot and dry element, like the elements, was an abstract principle and not identical with the normal solids, liquids and combustion phenomena we experience. According to Aristotle, the four elements rise or fall toward their natural place in concentric layers surrounding the center of the earth, in ancient Greek medicine, each of the four humours became associated with an element. Yellow bile was the humor identified with fire, since both were hot and dry, in alchemy the chemical element of sulfur was often associated with fire and its alchemical symbol and its symbol was an upward-pointing triangle. In alchemic tradition, metals are incubated by fire in the womb of the Earth, Agni is a Hindu and Vedic deity. The word agni is Sanskrit for fire, cognate with Latin ignis, Russian огонь, Agni has three forms, fire, lightning and the sun. Agni is one of the most important of the Vedic gods and he is the god of fire and the acceptor of sacrifices. The sacrifices made to Agni go to the deities because Agni is a messenger from and he is ever-young, because the fire is re-lit every day, yet he is also immortal
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Water (classical element)
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Water is one of the elements in ancient Greek philosophy, in the Asian Indian system Panchamahabhuta, and in the Chinese cosmological and physiological system Wu Xing. In contemporary esoteric traditions, it is associated with the qualities of emotion and intuition. Water was one of many proposed by the Pre-socratics, most of whom tried to reduce all things to a single substance. However, Empedocles of Acragas selected four archai for his four roots, air, fire, water, Empedocles roots became the four classical elements of Greek philosophy. Plato took over the four elements of Empedocles, in the Timaeus, his major cosmological dialogue, the Platonic solid associated with water is the icosahedron which is formed from twenty equilateral triangles. This makes water the element with the greatest number of sides, plato’s student Aristotle developed a different explanation for the elements based on pairs of qualities. The four elements were arranged concentrically around the center of the Universe to form the sublunary sphere, according to Aristotle, water is both cold and wet and occupies a place between air and earth among the elemental spheres. In ancient Greek medicine, each of the four humours became associated with an element, phlegm was the humor identified with water, since both were cold and wet. In alchemy, the element of mercury was often associated with water. Ap is the Vedic Sanskrit term for water, in Classical Sanskrit occurring only in the plural is not an element. v, āpas, the term is from PIE hxap water. In Hindu philosophy, the term refers to water as an element, one of the Panchamahabhuta, in Hinduism, it is also the name of the deva, a personification of water. The element water is associated with Chandra or the moon and Shukra. People born under the signs of Cancer, Scorpio and Pisces are thought to have dominant water personalities. Water personalities tend to be emotional, deep, nurturing, sympathetic, empathetic, water and the other Greek classical elements were incorporated into the Golden Dawn system. The elemental weapon of water is the cup, each of the elements has several associated spiritual beings. The archangel of water is Gabriel, the angel is Taliahad, the ruler is Tharsis, the king is Nichsa and it is referred to the upper right point of the pentagram in the Supreme Invoking Ritual of the Pentagram. Many of these associations have since spread throughout the occult community, water is one of the five elements that appear in most Wiccan traditions. Wicca in particular was influenced by the Golden Dawn system of magic and Aleister Crowleys mysticism, water Sea and river deity Different versions of the classical elements
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Aether (classical element)
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According to ancient and medieval science, aether, also spelled æther or ether, also called quintessence, is the material that fills the region of the universe above the terrestrial sphere. The concept of aether was used in several theories to explain natural phenomena, such as the traveling of light. The word αἰθήρ in Homeric Greek means pure, fresh air or clear sky, in Greek mythology, it was thought to be the pure essence that the gods breathed, filling the space where they lived, analogous to the air breathed by mortals. It is also personified as a deity, Aether, the son of Erebus, Aether is related to αἴθω to incinerate, and intransitive to burn, to shine. In Platos Timaeus speaking about air, Plato mentions that there is the most translucent kind which is called by the name of aether, but otherwise he adopted the classical system of four elements. Aristotle, who had been Platos student at the Akademia, agreed on this point with his former mentor, however, in his Book On the Heavens he introduced a new first element to the system of the classical elements of Ionian philosophy. He noted that the four classical elements were subject to change. The first element however, located in the regions and heavenly bodies. It was neither hot nor cold, neither wet nor dry, Aether did not follow Aristotelian physics either. Aether was also incapable of motion of quality or motion of quantity, Aether was only capable of local motion. Aether naturally moved in circles, and had no contrary, or unnatural, aristotle also noted that crystalline spheres made of aether held the celestial bodies. The idea of spheres and natural circular motion of aether led to Aristotles explanation of the observed orbits of stars. Medieval scholastic philosophers granted aether changes of density, in which the bodies of the planets were considered to be more dense than the medium which filled the rest of the universe, Robert Fludd stated that the aether was of the character that it was subtler than light. Fludd cites the 3rd-century view of Plotinus, concerning the aether as penetrative, Quintessence is the Latinate name of the fifth element used by medieval alchemists for a medium similar or identical to that thought to make up the heavenly bodies. It was noted there was very little presence of quintessence within the terrestrial sphere. Due to the low presence of quintessence, earth could be affected by what takes place within the heavenly bodies and this theory was developed in the 14th century text The testament of Lullius, attributed to Ramon Llull. The use of quintessence became popular within medieval alchemy and this elemental system spread rapidly throughout all of Europe and became popular with alchemists, especially in medicinal alchemy. Medicinal alchemy then sought to isolate quintessence and incorporate it within medicine, due to quintessences pure and heavenly quality, it was thought that through consumption one may rid oneself of any impurities or illnesses
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Iron
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Iron is a chemical element with symbol Fe and atomic number 26. It is a metal in the first transition series and it is by mass the most common element on Earth, forming much of Earths outer and inner core. It is the fourth most common element in the Earths crust, like the other group 8 elements, ruthenium and osmium, iron exists in a wide range of oxidation states, −2 to +6, although +2 and +3 are the most common. Elemental iron occurs in meteoroids and other low oxygen environments, but is reactive to oxygen, fresh iron surfaces appear lustrous silvery-gray, but oxidize in normal air to give hydrated iron oxides, commonly known as rust. Unlike the metals that form passivating oxide layers, iron oxides occupy more volume than the metal and thus flake off, Iron metal has been used since ancient times, although copper alloys, which have lower melting temperatures, were used even earlier in human history. Pure iron is soft, but is unobtainable by smelting because it is significantly hardened and strengthened by impurities, in particular carbon. A certain proportion of carbon steel, which may be up to 1000 times harder than pure iron. Crude iron metal is produced in blast furnaces, where ore is reduced by coke to pig iron, further refinement with oxygen reduces the carbon content to the correct proportion to make steel. Steels and iron alloys formed with metals are by far the most common industrial metals because they have a great range of desirable properties. Iron chemical compounds have many uses, Iron oxide mixed with aluminium powder can be ignited to create a thermite reaction, used in welding and purifying ores. Iron forms binary compounds with the halogens and the chalcogens, among its organometallic compounds is ferrocene, the first sandwich compound discovered. Iron plays an important role in biology, forming complexes with oxygen in hemoglobin and myoglobin. Iron is also the metal at the site of many important redox enzymes dealing with cellular respiration and oxidation and reduction in plants. A human male of average height has about 4 grams of iron in his body and this iron is distributed throughout the body in hemoglobin, tissues, muscles, bone marrow, blood proteins, enzymes, ferritin, hemosiderin, and transport in plasma. The mechanical properties of iron and its alloys can be evaluated using a variety of tests, including the Brinell test, Rockwell test, the data on iron is so consistent that it is often used to calibrate measurements or to compare tests. An increase in the content will cause a significant increase in the hardness. Maximum hardness of 65 Rc is achieved with a 0. 6% carbon content, because of the softness of iron, it is much easier to work with than its heavier congeners ruthenium and osmium. Because of its significance for planetary cores, the properties of iron at high pressures and temperatures have also been studied extensively
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Empedocles
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Empedocles was a Greek pre-Socratic philosopher and a citizen of Acragas, a Greek city in Sicily. Empedocles philosophy is best known for originating the theory of the four classical elements. He also proposed forces he called Love and Strife which would mix as well as separate the elements and these physical speculations were part of a history of the universe which also dealt with the origin and development of life. Influenced by the Pythagoreans, Empedocles was a vegetarian who supported the doctrine of reincarnation and he is generally considered the last Greek philosopher to have recorded his ideas in verse. Some of his survives, more than is the case for any other pre-Socratic philosopher. Empedocles death was mythologized by ancient writers, and has been the subject of a number of literary treatments, Empedocles was born, c.490 BC, at Acragas in Sicily to a distinguished family. Very little is known about his life and his father Meto seems to have been instrumental in overthrowing the tyrant of Agrigentum, presumably Thrasydaeus in 470 BC. Empedocles continued this tradition by helping to overthrow the succeeding oligarchic government, Empedocles was acquainted or connected by friendship with the physicians Pausanias and Acron, with various Pythagoreans, and even, it is said, with Parmenides and Anaxagoras. The only pupil of Empedocles who is mentioned is the sophist, according to Aristotle, he died at the age of sixty, even though other writers have him living up to the age of one hundred and nine. The contemporary Life of Empedocles by Xanthus has been lost, Empedocles is considered the last Greek philosopher to write in verse and the surviving fragments of his teaching are from two poems, Purifications and On Nature. Lucretius speaks of him with enthusiasm, and evidently viewed him as his model, the two poems together comprised 5000 lines. About 550 lines of his survive, although because ancient writers rarely mentioned which poem they were quoting. Some scholars now believe there was only one poem. We possess only about 100 lines of his Purifications and it seems to have given a mythical account of the world which may, nevertheless, have been part of Empedocles philosophical system. Humans, animals, and even plants are such spirits, the moral conduct recommended in the poem may allow us to become like gods again. There are about 450 lines of his poem On Nature extant, the poem originally consisted of 2000 lines of hexameter verse, and was addressed to Pausanias. It was this poem which outlined his philosophical system, although acquainted with the theories of the Eleatics and the Pythagoreans, Empedocles did not belong to any one definite school. An eclectic in his thinking, he combined much that had been suggested by Parmenides, Pythagoras and he was a firm believer in Orphic mysteries, as well as a scientific thinker and a precursor of physical science
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Scientific revolution
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While its dates are debated, the publication in 1543 of Nicolaus Copernicuss De revolutionibus orbium coelestium is often cited as marking the beginning of the scientific revolution. By the end of the 18th century, the revolution had given way to the Age of Reflection. Great advances in science have been termed revolutions since the 18th century, in 1747, Clairaut wrote that Newton was said in his own lifetime to have created a revolution. The word was used in the preface to Lavoisiers 1789 work announcing the discovery of oxygen. Few revolutions in science have immediately excited so much general notice as the introduction of the theory of oxygen, lavoisier saw his theory accepted by all the most eminent men of his time, and established over a great part of Europe within a few years from its first promulgation. In the 19th century, William Whewell described the revolution in science itself -- the scientific method -- that had taken place in the 15th–16th century. This gave rise to the view of the scientific revolution today, A new view of nature emerged. Science became a discipline, distinct from both philosophy and technology and came to be regarded as having utilitarian goals. The scientific revolution is traditionally assumed to start with the Copernican Revolution, in the 20th century, Alexandre Koyré introduced the term scientific revolution, centering his analysis on Galileo. The term was popularized by Butterfield in his Origins of Modern Science, the scientific revolution led to the establishment of several modern sciences. In 1984, Joseph Ben-David wrote, Rapid accumulation of knowledge, the new kind of scientific activity emerged only in a few countries of Western Europe, and it was restricted to that small area for about two hundred years. Many contemporary writers and modern historians claim that there was a change in world view. Looms so large as the origin both of the modern world and of the modern mentality that our customary periodization of European history has become an anachronism. Some scholars have noted a direct tie between particular aspects of traditional Christianity and the rise of science, the Aristotelian tradition was still an important intellectual framework in the 17th century, although by that time natural philosophers had moved away from much of it. Key scientific ideas dating back to classical antiquity had changed drastically over the years, the ideas that remained, which were transformed fundamentally during the scientific revolution, include, Aristotles cosmology that placed the Earth at the center of a spherical hierarchic cosmos. The terrestrial and celestial regions were made up of different elements which had different kinds of natural movement, the terrestrial region, according to Aristotle, consisted of concentric spheres of the four elements—earth, water, air, and fire. All bodies naturally moved in straight lines until they reached the sphere appropriate to their elemental composition—their natural place, all other terrestrial motions were non-natural, or violent. The celestial region was made up of the element, aether
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Chemical element
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A chemical element or element is a species of atoms having the same number of protons in their atomic nuclei. There are 118 elements that have identified, of which the first 94 occur naturally on Earth with the remaining 24 being synthetic elements. There are 80 elements that have at least one stable isotope and 38 that have exclusively radioactive isotopes, iron is the most abundant element making up Earth, while oxygen is the most common element in the Earths crust. Chemical elements constitute all of the matter of the universe. The two lightest elements, hydrogen and helium, were formed in the Big Bang and are the most common elements in the universe. The next three elements were formed mostly by cosmic ray spallation, and are rarer than those that follow. Formation of elements with from 6 to 26 protons occurred and continues to occur in main sequence stars via stellar nucleosynthesis, the high abundance of oxygen, silicon, and iron on Earth reflects their common production in such stars. The term element is used for atoms with a number of protons as well as for a pure chemical substance consisting of a single element. A single element can form multiple substances differing in their structure, when different elements are chemically combined, with the atoms held together by chemical bonds, they form chemical compounds. Only a minority of elements are found uncombined as relatively pure minerals, among the more common of such native elements are copper, silver, gold, carbon, and sulfur. All but a few of the most inert elements, such as gases and noble metals, are usually found on Earth in chemically combined form. While about 32 of the elements occur on Earth in native uncombined forms. For example, atmospheric air is primarily a mixture of nitrogen, oxygen, and argon, the history of the discovery and use of the elements began with primitive human societies that found native elements like carbon, sulfur, copper and gold. Later civilizations extracted elemental copper, tin, lead and iron from their ores by smelting, using charcoal, alchemists and chemists subsequently identified many more, almost all of the naturally occurring elements were known by 1900. Save for unstable radioactive elements with short half-lives, all of the elements are available industrially, almost all other elements found in nature were made by various natural methods of nucleosynthesis. On Earth, small amounts of new atoms are produced in nucleogenic reactions, or in cosmogenic processes. Of the 94 naturally occurring elements, those with atomic numbers 1 through 82 each have at least one stable isotope, Isotopes considered stable are those for which no radioactive decay has yet been observed. Elements with atomic numbers 83 through 94 are unstable to the point that radioactive decay of all isotopes can be detected, the very heaviest elements undergo radioactive decay with half-lives so short that they are not found in nature and must be synthesized
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Dynamics of the celestial spheres
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Ancient, medieval and Renaissance astronomers and philosophers developed many different theories about the dynamics of the celestial spheres. Most of these models were qualitative, although a few of them incorporated quantitative analyses that related speed, in considering the physics of the celestial spheres, scholars followed two different views about the material composition of the celestial spheres. For Plato, the regions were made mostly out of fire on account of fires mobility. This account was compatible with Aristotles meteorology of a region in the upper air. Earth and water had a natural heaviness, which they expressed by moving downward toward the center of the universe, fire and air had a natural lightness, such that they moved upward, away from the center. Aether, being neither heavy nor light, moved naturally around the center, as early as Plato, philosophers considered the heavens to be moved by immaterial agents. Plato believed the cause to be a world-soul, created according to principles, which governed the daily motion of the heavens. Aristotle proposed the existence of divine unmoved movers which act as final causes, in his Metaphysics, Aristotle maintained that an individual unmoved mover would be required to insure each individual motion in the heavens. In his Planetary Hypotheses, Ptolemy rejected the Aristotelian concept of a prime mover, maintaining instead that the planets have souls. John Philoponus considered that the heavens were made of fire, not of aether and this is interpreted as an application of the concept of impetus to the motion of the celestial spheres. The Islamic philosophers al-Farabi and Avicenna, following Plotinus, maintained that Aristotles movers, called intelligences, a first intelligence emanated from God, and from the first intelligence emanated a sphere, its soul, and a second intelligence. The process continued down through the celestial spheres until the sphere of the Moon, its soul, and they considered that each sphere was moved continually by its soul, seeking to emulate the perfection of its intelligence. Avicenna maintained that besides an intelligence and its soul, each sphere was moved by a natural inclination. The spheres thus moved with a natural nonviolent motion, considering how the soul acts, he maintained that the soul moves its sphere without effort, for the celestial material has no tendency to a contrary motion. He maintained that the spheres were imaginary things and more tenuous than a spiders web. In the Early Middle Ages, Platos picture of the heavens was dominant among European philosophers, the soul shares the motion of its sphere and causes the sphere to move through its love and desire for the unmoved separate intelligence. Moreover, Aquinas rejected the idea that bodies are moved by an internal nature. Attributing souls to the spheres was theologically controversial, as that could make them animals, after the Condemnations of 1277, most philosophers came to reject the idea that the celestial spheres had souls
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Sublunary sphere
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The sublunary sphere is a concept in Aristotelian physics derived from Greek astronomy. It is the region of the geocentric cosmos below the Moon, consisting of the four elements, earth, water, air. The sublunary sphere was the realm of changing nature, beginning with the Moon, up to the limits of the universe, everything was permanent, regular and unchanging – the region of aether where the planets and stars are located. Only in the sublunary sphere did the powers of physics hold sway, plato and Aristotle helped to formulate the original theory of a sublunary sphere in antiquity - the idea usually going hand in hand with geocentrism and the concept of a spherical Earth. Avicenna carried forward into the Middle Ages the Aristotelian idea of generation and corruption being limited to the sublunary sphere, the result for medieval/Renaissance mentalities was a pervasive awareness of the existence, at the Moon, of what C. S. Lewis called this great divide. In their wake Tycho Brahes observations of a new star and of comets in the supposedly unchanging heavens further undermined the Aristotelian view, Thomas Kuhn saw scientists new ability to see change in the incorruptible heavens as a classic example of the new possibilities opened up by a paradigm shift. Dante envisaged Mt Purgatory as being so high that it reached above the sublunary sphere, samuel Johnson praised Shakespeares plays as “exhibiting the real state of sublunary nature, which partakes of good and evil, joy and sorrow, intermingled”. J. Barnes, Aristotle M. A. Orr, Dante and the Medieval Astronomers Thomas Kuhn, The Copernican Revolution The Geocentric or Ptolemaic Notion of the Universe
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Homer
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Homer is the name ascribed by the ancient Greeks to the semi-legendary author of the Iliad and the Odyssey, two epic poems which are the central works of Greek literature. The Odyssey focuses on the home of Odysseus, king of Ithaca. Many accounts of Homers life circulated in classical antiquity, the most widespread being that he was a bard from Ionia. The modern scholarly consensus is that these traditions do not have any historical value, the Homeric question - by whom, when, where and under what circumstances were the Iliad and Odyssey composed - continues to be debated. Broadly speaking, modern scholarly opinion on the authorship question falls into two camps, one group holds that most of the Iliad and the Odyssey is the work of a single poet of genius. The other considers the Homeric poems to be the crystallization of a process of working and re-working by many contributors and it is generally accepted that the poems were composed at some point around the late eighth or early seventh century B. C. Most researchers believe that the poems were transmitted orally. The Homeric epics were the greatest influence on ancient Greek culture and education, to Plato, the chronological period of Homer depends on the meaning to be assigned to the word Homer. Was Homer a single person, an imaginary person representing a group of poets and this information is often called the world of Homer. The Homeric period would in that cover a number of historical periods, especially the Mycenaean Age. Considered word-for-word, the texts as we know them are the product of the scholars of the last three centuries. Each edition of the Iliad or Odyssey is a different, as the editors rely on different manuscripts and fragments. The term accuracy reveals a belief in an original uniform text. The manuscripts of the work currently available date to no earlier than the 10th century. These are at the end of a missing thousand-year chain of copies made as each generation of manuscripts disintegrated or were lost or destroyed and these numerous manuscripts are so similar that a single original can be postulated. The time gap in the chain is bridged by the scholia, or notes, on the existing manuscripts, librarian of the Library of Alexandria, he had noticed a wide divergence in the works attributed to Homer, and was trying to restore a more authentic copy. He had collected several manuscripts, which he named, the Sinopic, the one he selected for correction was the koine, which Murray translates as the Vulgate. Aristarchus was known for his selection of material
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Aether (mythology)
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Aether /ˈiːθər/ or Aither, in ancient Greece, was one of the primordial deities. Aether is the personification of the upper air and he embodies the pure upper air that the gods breathe, as opposed to the normal air breathed by mortals. Like Tartarus and Erebus, Aether may have had shrines in ancient Greece, in Hesiods Theogony, Aether, was the son of Erebus and Nyx, and the brother of Hemera. The Roman mythographer Hyginus, says Aether was the son of Chaos, started his Fabulae with a strange hodgepodge of Greek and Roman cosmogonies and early genealogies. It begins as follows, Ex Caligine Chaos, Ex Chao et Caligine Nox Dies Erebus Aether. His genealogy looks like a derivation from Hesiod, but it starts with the un-Hesiodic and un-Roman Caligo, darkness probably did occur in a cosmogonic poem of Alcman, but it seems only fair to say that it was not prominent in Greek cosmogonies. Aristophanes states that Aether was the son of Erebus, however, Damascius says that Aether, Erebus and Chaos were siblings, and the offspring of Chronos. According to Epiphanius, the world began as an egg, encircled by Time. Together they constricted the egg, squeezing its matter with great force, after that, the atoms sorted themselves out. The lighter and finer ones floated above and became the Bright Air and the rarefied Wind, while the heavier and denser atoms sank and became the Earth, see also Platos Myth of Er. The fifth Orphic hymn to Aether describes the substance as the high-reigning, ever indestructible power of Zeus, the best element, Greek Religion and Culture, the Bible and the Ancient Near East. Jerusalem Studies in Religion and Culture, gantz, Timothy, Early Greek Myth, A Guide to Literary and Artistic Sources, Johns Hopkins University Press,1996, Two volumes, ISBN 978-0-8018-5360-9, ISBN 978-0-8018-5362-3. Grimal, Pierre, The Dictionary of Classical Mythology, Wiley-Blackwell,1996, Hesiod, Theogony, in The Homeric Hymns and Homerica with an English Translation by Hugh G. Evelyn-White, Cambridge, MA. Harvard University Press, London, William Heinemann Ltd.1914. Hammond, N. G. L. and H. H. Scullard, The Oxford Classical Dictionary, Second Edition, Hyginus, Gaius Julius, The Myths of Hyginus. Edited and translated by Mary A. Grant, Lawrence, University of Kansas Press,1960, smith, William, Dictionary of Greek and Roman Biography and Mythology, London
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Mount Olympus
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Mount Olympus is the highest mountain in Greece. It is located in the Olympus Range on the border between Thessaly and Macedonia, between the units of Pieria and Larissa, about 80 km southwest from Thessaloniki. Mount Olympus has 52 peaks, deep gorges, and exceptional biodiversity, the highest peak Mytikas, meaning nose, rises to 2,918 metres. It is one of the highest peaks in Europe in terms of topographic prominence, Olympus was notable in Greek mythology as the home of the Greek gods, on the Mytikas peak. Mount Olympus is also noted for its rich flora with several species. It has been a National Park, the first in Greece, since 1938 and it is also a Worlds Biosphere Reserve. Every year thousands of people visit Olympus to admire its fauna and flora, to tour its slopes, organized mountain refuges and various mountaineering and climbing routes are available to visitors who want to explore it. The usual starting point is the town of Litochoro, on the foothills of the mountain,100 km from Thessaloniki, where, in the beginning of every summer. The shape of Olympus was formed by rain and wind, which produced an isolated tower almost 3,000 metres above the sea, Olympus has many peaks and an almost circular shape. The mountain has a circumference of 150 kilometres, a diameter of 26 kilometres. To the northwest lies the Vlach village of Kokkinoplou, the Makryrema stream separates Olympus from the massif of Voulgara. The villages Petra, Vrontou and Dion lie to the northwest, while on the side there is the town of Litochoro. On its southeastern side, the Ziliana gorge divides Mount Olympus from Kato Olympos, while on its foothills, there are the villages Sykaminea. The Aghias Triadas Sparmou Monastery and the village Pythion lie to the west, Olympus dry foothills are known as the Xirokampi, containing chaparral and small animals. Further east, the plain of Dion is fertile and watered by the streams originate on Olympus. Mount Olympus is formed of rock laid down 200 million years ago in a shallow sea. Various geological events that caused the emergence of the whole region. Around one million years ago glaciers covered Olympus and created its plateaus, the complicated geological past of the region is obvious on the morphology of Olympus and its National Park
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Classical planet
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The word planet comes from the Greek word πλανήτης, planētēs wanderer, expressing the fact that these objects move across the celestial sphere relative to the fixed stars. In the original papyri of these Greek horoscopes, there are found a circle with one ray for the Sun, the written symbols for Mercury, Venus, Jupiter, and Saturn have been traced to forms found in late Greek papyri. The symbols for Jupiter and Saturn are identified as monograms of the letters of the corresponding Greek names. A. S. D. Maunder finds antecedents of the symbols in earlier sources. The modern sun symbol, pictured as a circle with a dot, the Ptolemaic system used in Greek astronomy placed the planets in order, closest to Earth to furthest, as the Moon, Mercury, Venus, Sun, Mars, Jupiter, and Saturn. In addition the day was divided into 7-hour intervals, each ruled by one of the planets, the first hour of each day was named after the ruling planet, giving rise to the names and order of the Roman seven-day week. The modern English days of the week were inherited from gods of the old Germanic Norse culture—Thursday = Thor, Friday = Frige. It can be correlated that the Norse gods were attributed to each Roman planet and its god, in alchemy, each classical planet was associated with one of the seven metals known to the classical world. As a result, the glyphs for the metal and associated planet coincide. Alchemists believed the other metals were variants of these seven. Astrology has used the concept of elements from antiquity up until the present day today. Most modern astrologers use the four classical elements extensively, and indeed they are viewed as a critical part of interpreting the astrological chart. Traditionally, each of the seven planets in the system as known to the ancients was associated with, held dominion over. Mercury and Venus are visible only in twilight hours because their orbits are interior to that of Earth, Venus is the third-brightest object in the sky and the most prominent planet. Mercury is more difficult to see due to its proximity to the Sun, lengthy twilight and an extremely low angle at maximum elongations make optical filters necessary to see Mercury from extreme polar locations. Mars is at its brightest when it is in opposition, which occurs approximately every twenty-five months, Jupiter and Saturn are the largest of the five planets, but are farther from the Sun, and therefore receive less sunlight. Nonetheless, Jupiter is often the next brightest object in the sky after Venus
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