|
History Of Optics
Optics began with the development of lenses by the ancient Egyptians and Mesopotamians, followed by theories on light and vision developed by ancient Greek philosophers, and the development of geometrical optics in the Greco-Roman world. The word ''optics'' is derived from the Greek term meaning 'appearance, look'. Optics was significantly reformed by the developments in the medieval Islamic world, such as the beginnings of physical and physiological optics, and then significantly advanced in early modern Europe, where diffractive optics began. These earlier studies on optics are now known as "classical optics". The term "modern optics" refers to areas of optical research that largely developed in the 20th century, such as wave optics and quantum optics. Early history In ancient India, the philosophical schools of Samkhya and Vaisheshika, from around the 6th–5th century BC, developed theories on light. According to the Samkhya school, light is one of the five fundamental ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Orbit 2
In celestial mechanics, an orbit is the curved trajectory of an physical body, object such as the trajectory of a planet around a star, or of a natural satellite around a planet, or of an satellite, artificial satellite around an object or position in space such as a planet, moon, asteroid, or Lagrange point. Normally, orbit refers to a regularly repeating trajectory, although it may also refer to a non-repeating trajectory. To a close approximation, planets and satellites follow elliptic orbits, with the barycenter, center of mass being orbited at a focal point of the ellipse, as described by Kepler's laws of planetary motion. For most situations, orbital motion is adequately approximated by Newtonian mechanics, which explains Newton's law of universal gravitation, gravity as a force obeying an inverse-square law. However, Albert Einstein's general theory of relativity, which accounts for gravity as due to curvature of spacetime, with orbits following geodesics, provides a mor ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Samkhya
''Samkhya'' or ''Sankya'' (; Sanskrit सांख्य), IAST: ') is a Dualism (Indian philosophy), dualistic Āstika and nāstika, school of Indian philosophy. It views reality as composed of two independent principles, ''purusha, puruṣa'' ('consciousness' or spirit); and ''prakṛti'', (nature or matter, including the human mind and emotions). ''Puruṣa'' is the witness-consciousness. It is absolute, independent, free, beyond perception, above any experience by mind or senses, and impossible to describe in words. Unmanifest ''prakriti'' is matter or nature. It is inactive, unconscious, and is a balance of the three ''guṇas'' (qualities or innate tendencies), namely ''sattva'' , ''rajas'', and ''Tamas (philosophy), tamas''. When prakṛti comes into contact with Purusha this balance is disturbed, and Prakriti becomes manifest, evolving twenty-three tattvas, namely intellect (buddhi, mahat), ego (ahamkara) mind (Manas (early Buddhism), manas); the five sensory capacitie ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Greek Mathematics
Greek mathematics refers to mathematics texts and ideas stemming from the Archaic through the Hellenistic and Roman periods, mostly extant from the 7th century BC to the 4th century AD, around the shores of the Eastern Mediterranean. Greek mathematicians lived in cities spread over the entire Eastern Mediterranean from Italy to North Africa but were united by Greek culture and the Greek language. The word "mathematics" itself derives from the grc, , máthēma , meaning "subject of instruction". The study of mathematics for its own sake and the use of generalized mathematical theories and proofs is an important difference between Greek mathematics and those of preceding civilizations. Origins of Greek mathematics The origin of Greek mathematics is not well documented. The earliest advanced civilizations in Greece and in Europe were the Minoan and later Mycenaean civilizations, both of which flourished during the 2nd millennium BCE. While these civilizations possessed writing and ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Euclid's Optics
Euclid's ''Optics'' ( grc-gre, Ὀπτικά), is a work on the geometry of vision written by the Greek mathematician Euclid around 300 BC. The earliest surviving manuscript of ''Optics'' is in Greek and dates from the 10th century AD. The work deals almost entirely with the geometry of vision, with little reference to either the physical or psychological aspects of sight. No Western scientist had previously given such mathematical attention to vision. Euclid's ''Optics'' influenced the work of later Greek, Islamic, and Western European Renaissance scientists and artists. Historical significance Writers before Euclid had developed theories of vision. However, their works were mostly philosophical in nature and lacked the mathematics that Euclid introduced in his ''Optics''. Efforts by the Greeks prior to Euclid were concerned primarily with the physical dimension of vision. Whereas Plato and Empedocles thought of the visual ray as "luminous and ethereal emanation", Euclid ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Association Of Asia Pacific Physical Societies
Association may refer to: *Club (organization), an association of two or more people united by a common interest or goal *Trade association, an organization founded and funded by businesses that operate in a specific industry *Voluntary association, a body formed by individuals to accomplish a purpose, usually as volunteers Association in various fields of study *Association (archaeology), the close relationship between objects or contexts. *Association (astronomy), combined or co-added group of astronomical exposures *Association (chemistry) *Association (ecology), a type of ecological community *Genetic association, when one or more genotypes within a population co-occur *Association (object-oriented programming), defines a relationship between classes of objects *Association (psychology), a connection between two or more concepts in the mind or imagination *Association (statistics), a statistical relationship between two variables *File association, associates a file with a so ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Courier Dover
Dover Publications, also known as Dover Books, is an American book publisher founded in 1941 by Hayward and Blanche Cirker. It primarily reissues books that are out of print from their original publishers. These are often, but not always, books in the public domain. The original published editions may be scarce or historically significant. Dover republishes these books, making them available at a significantly reduced cost. Classic reprints Dover reprints classic works of literature, classical sheet music, and public-domain images from the 18th and 19th centuries. Dover also publishes an extensive collection of mathematical, scientific, and engineering texts. It often targets its reprints at a niche market, such as woodworking. Starting in 2015, the company branched out into graphic novel reprints, overseen by Dover acquisitions editor and former comics writer and editor Drew Ford. Most Dover reprints are photo facsimiles of the originals, retaining the original pagination and t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Aphrodite
Aphrodite ( ; grc-gre, Ἀφροδίτη, Aphrodítē; , , ) is an ancient Greek goddess associated with love, lust, beauty, pleasure, passion, and procreation. She was syncretized with the Roman goddess . Aphrodite's major symbols include myrtles, roses, doves, sparrows, and swans. The cult of Aphrodite was largely derived from that of the Phoenician goddess Astarte, a cognate of the East Semitic goddess Ishtar, whose cult was based on the Sumerian cult of Inanna. Aphrodite's main cult centers were Cythera, Cyprus, Corinth, and Athens. Her main festival was the Aphrodisia, which was celebrated annually in midsummer. In Laconia, Aphrodite was worshipped as a warrior goddess. She was also the patron goddess of prostitutes, an association which led early scholars to propose the concept of "sacred prostitution" in Greco-Roman culture, an idea which is now generally seen as erroneous. In Hesiod's ''Theogony'', Aphrodite is born off the coast of Cythera from the foam (, ) ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Classical Element
Classical elements typically refer to earth, water, air, fire, and (later) aether which were proposed to explain the nature and complexity of all matter in terms of simpler substances. Ancient cultures in Greece, Tibet, and India had similar lists which sometimes referred, in local languages, to "air" as "wind" and the fifth element as "void". 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 (the idea of very small, indivisible portions of matter), but other interpretations considered the elements to be divisible into infinitely small pieces without changing their nature. While the classification of the material world in ancient Indian, Hellenistic Egypt, and ancient Greece into Air, Earth, Fire and Water was ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Empedocles
Empedocles (; grc-gre, Ἐμπεδοκλῆς; , 444–443 BC) was a Greek pre-Socratic philosopher and a native citizen of Akragas, a Greek city in Sicily. Empedocles' philosophy is best known for originating the cosmogonic theory of the four classical elements. He also proposed forces he called Love and Strife which would mix and separate the elements, respectively. Empedocles challenged the practice of animal sacrifice and killing animals for food. He developed a distinctive doctrine of reincarnation. He is generally considered the last Greek philosopher to have recorded his ideas in verse. Some of his work 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. Life Although the exact dates of Empedocles birth and death are unknown and ancient accounts of his life conflict on the exact details, they agree that he was born in the early 5th ce ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Vishnu Purana
The Vishnu Purana (IAST:, sa, विष्णुपुराण) is one of the eighteen Puranas#Mahapuranas, Mahapuranas, a genre of ancient and medieval texts of Hinduism. It is an important Pancharatra text in the Vaishnavism literature corpus. The manuscripts of ''Vishnu Purana'' have survived into the modern era in many versions. More than any other major Purana, the ''Vishnu Purana'' presents its contents in ''Pancalaksana'' format – ''Sarga'' (cosmogony), ''Pratisarga'' (cosmology), ''Vamśa'' (genealogy of the gods, sages and kings), ''Manvantara'' (cosmic cycles), and ''Vamśānucaritam'' (legends during the times of various kings). Some manuscripts of the text are notable for not including sections found in other major Puranas, such as those on ''Mahatmyas'' and tour guides on pilgrimage, but some versions include chapters on temples and travel guides to sacred pilgrimage sites. The text is also notable as the earliest Purana to have been translated and published ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Atom
Every atom is composed of a nucleus and one or more electrons bound to the nucleus. The nucleus is made of one or more protons and a number of neutrons. Only the most common variety of hydrogen has no neutrons. Every solid, liquid, gas, and plasma is composed of neutral or ionized atoms. Atoms are extremely small, typically around 100 picometers across. They are so small that accurately predicting their behavior using classical physics, as if they were tennis balls for example, is not possible due to quantum effects. More than 99.94% of an atom's mass is in the nucleus. The protons have a positive electric charge, the electrons have a negative electric charge, and the neutrons have no electric charge. If the number of protons and electrons are equal, then the atom is electrically neutral. If an atom has more or fewer electrons than protons, then it has an overall negative or positive charge, respectively – such atoms are called ions. The electrons of an atom are a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Atomism
Atomism (from Greek , ''atomon'', i.e. "uncuttable, indivisible") is a natural philosophy proposing that the physical universe is composed of fundamental indivisible components known as atoms. References to the concept of atomism and its atoms appeared in both ancient Greek and ancient Indian philosophical traditions. Leucippus is the earliest figure whose commitment to atomism is well attested and he is usually credited with inventing atomism. He and other ancient Greek atomists theorized that nature consists of two fundamental principles: ''atom'' and ''void''. Clusters of different shapes, arrangements, and positions give rise to the various macroscopic substances in the world.Berryman, Sylvia, "Ancient Atomism", ''The Stanford Encyclopedia of Philosophy'' (Fall 2008 Edition), Edward N. Zalta (ed.)online/ref> The particles of chemical matter for which chemists and other natural philosophers of the early 19th century found experimental evidence were thought to be indivisibl ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
