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History Of Lensmaking
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 ... [...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] |
