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Light Fantastic (TV Series)
''Light Fantastic'' is the title of a television documentary series that explores the phenomenon of light and aired in December 2004 on BBC Four. The series comprised four programmes respectively titled: "Let There Be Light"; "The Light of Reason"; "The Stuff of Light"; and "Light, the Universe and Everything." The material was presented by Cambridge academic Simon Schaffer.http://www.bbc.co.uBBC Light Fantastic/ref> Let There Be Light The first episode shows how the desire, by Greek, Arab and Christian scholars to penetrate the divine nature of light led to modern science's origins. The programme explores the contributions of Empedocles; Euclid; Al Hazen; Roger Bacon; Descartes and Isaac Newton.''Let There Be Light'' 7 August 2006 01:50 BBC Four Greek scholars The nature of light, and how we see, was first investigated by the early Greek philosophers. Light seemed to fill all space while allowing a kind of penetration of the world thus offering a clue to the structure of the w ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Documentary Series
Television documentaries are televised media productions that screen documentaries. Television documentaries exist either as a television documentary series or as a television documentary film. *Television documentary series, sometimes called docuseries, are television series screened within an ordered collection of two or more televised episodes. *Television documentary films exist as a singular documentary film to be broadcast via a documentary channel or a news-related channel. Occasionally, documentary films that were initially intended for televised broadcasting may be screened in a cinema. Documentary television rose to prominence during the 1940s, spawning from earlier cinematic documentary filmmaking ventures. Early production techniques were highly inefficient compared to modern recording methods. Early television documentaries typically featured historical, wartime, investigative or event-related subject matter. Contemporary television documentaries have extended ... [...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", Euc ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Galileo
Galileo di Vincenzo Bonaiuti de' Galilei (15 February 1564 – 8 January 1642) was an Italian astronomer, physicist and engineer, sometimes described as a polymath. Commonly referred to as Galileo, his name was pronounced (, ). He was born in the city of Pisa, then part of the Duchy of Florence. Galileo has been called the "father" of observational astronomy, modern physics, the scientific method, and modern science. Galileo studied speed and velocity, gravity and free fall, the principle of relativity, inertia, projectile motion and also worked in applied science and technology, describing the properties of pendulums and " hydrostatic balances". He invented the thermoscope and various military compasses, and used the telescope for scientific observations of celestial objects. His contributions to observational astronomy include telescopic confirmation of the phases of Venus, observation of the four largest satellites of Jupiter, observation of Satu ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Tycho Brahe
Tycho Brahe ( ; born Tyge Ottesen Brahe; generally called Tycho (14 December 154624 October 1601) was a Danish astronomer, known for his comprehensive astronomical observations, generally considered to be the most accurate of his time. He was known during his lifetime as an astronomer, astrologer, and alchemist. He was the last major astronomer before the invention of the telescope. An heir to several noble families, Tycho was well-educated. He took an interest in astronomy and in the creation of more accurate instruments of measurement. He worked to combine what he saw as the geometrical benefits of Copernican heliocentrism with the philosophical benefits of the Ptolemaic system, and devised the Tychonic system, his own version of a model of the universe, with the Sun orbiting the Earth, and the planets as orbiting the Sun. In ''De nova stella'' (1573), he refuted the Aristotelian belief in an unchanging celestial realm. His measurements indicated that "new stars" (''st ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Opus Majus
The ''Opus Majus'' (Latin for "Greater Work") is the most important work of Roger Bacon. It was written in Medieval Latin, at the request of Pope Clement IV, to explain the work that Bacon had undertaken. The 878-page treatise ranges over all aspects of natural science, from grammar and logic to mathematics, physics, and philosophy. Bacon sent his work to the Pope in 1267. It was followed later the same year by a smaller second work, his '' Opus Minus'', which was intended as an abstract or summary of the longer work, followed shortly by a third work, ''Opus Tertium'', as a preliminary introduction to the other two. Contents The ''Opus Majus'' is divided into seven parts: #Part one considers the obstacles to real wisdom and truth, classifying the causes of error (''offendicula'') into four categories: following a weak or unreliable authority, custom, the ignorance of others, and concealing one's own ignorance by pretended knowledge. #Part two considers the relationship between ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Book Of Optics
The ''Book of Optics'' ( ar, كتاب المناظر, Kitāb al-Manāẓir; la, De Aspectibus or ''Perspectiva''; it, Deli Aspecti) is a seven-volume treatise on optics and other fields of study composed by the medieval Arab scholar Ibn al-Haytham, known in the West as Alhazen or Alhacen (965–c. 1040 AD). The ''Book of Optics'' presented experimentally founded arguments against the widely held extramission theory of vision (as held by Euclid in his ''Optica''), and proposed the modern intromission theory, the now accepted model that vision takes place by light entering the eye.D. C. Lindberg (1976), ''Theories of Vision from al-Kindi to Kepler'', Chicago, Univ. of Chicago Press The book is also noted for its early use of the scientific method, its description of the camera obscura, and its formulation of Alhazen's problem. The book extensively affected the development of optics, physics and mathematics in Europe between the 13th and 17th centuries. Vision t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Reflection (physics)
Reflection is the change in direction of a wavefront at an interface between two different media so that the wavefront returns into the medium from which it originated. Common examples include the reflection of light, sound and water waves. The ''law of reflection'' says that for specular reflection (for example at a mirror) the angle at which the wave is incident on the surface equals the angle at which it is reflected. In acoustics, reflection causes echoes and is used in sonar. In geology, it is important in the study of seismic waves. Reflection is observed with surface waves in bodies of water. Reflection is observed with many types of electromagnetic wave, besides visible light. Reflection of VHF and higher frequencies is important for radio transmission and for radar. Even hard X-rays and gamma rays can be reflected at shallow angles with special "grazing" mirrors. Reflection of light Reflection of light is either '' specular'' (mirror-like) or '' diffuse'' (retai ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Refraction
In physics, refraction is the redirection of a wave as it passes from one medium to another. The redirection can be caused by the wave's change in speed or by a change in the medium. Refraction of light is the most commonly observed phenomenon, but other waves such as sound waves and water waves also experience refraction. How much a wave is refracted is determined by the change in wave speed and the initial direction of wave propagation relative to the direction of change in speed. For light, refraction follows Snell's law, which states that, for a given pair of media, the ratio of the sines of the angle of incidence ''θ1'' and angle of refraction ''θ2'' is equal to the ratio of phase velocities (''v''1 / ''v''2) in the two media, or equivalently, to the refractive indices (''n''2 / ''n''1) of the two media. :\frac =\frac=\frac Optical prisms and lenses use refraction to redirect light, as does the human eye. The refractive index of materials varies with the wa ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Intromission Theory
Visual perception is the ability to interpret the surrounding environment through photopic vision (daytime vision), color vision, scotopic vision (night vision), and mesopic vision (twilight vision), using light in the visible spectrum reflected by objects in the environment. This is different from visual acuity, which refers to how clearly a person sees (for example "20/20 vision"). A person can have problems with visual perceptual processing even if they have 20/20 vision. The resulting perception is also known as vision, sight, or eyesight (adjectives ''visual'', ''optical'', and ''ocular'', respectively). The various physiological components involved in vision are referred to collectively as the visual system, and are the focus of much research in linguistics, psychology, cognitive science, neuroscience, and molecular biology, collectively referred to as vision science. Visual system In humans and a number of other mammals, light enters the eye through the cornea a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Flooding Of The Nile
The flooding of the Nile has been an important natural cycle in Egypt since ancient times. It is celebrated by Egyptians as an annual holiday for two weeks starting August 15, known as ''Wafaa El-Nil''. It is also celebrated in the Coptic Church by ceremonially throwing a martyr's relic into the river, hence the name, The Martyr's Finger (, ). The flooding of the Nile was poetically described in myth as Isis's tears of sorrow for Osiris when killed by their brother Set. Flooding cycle The flooding of the Nile is the result of the yearly monsoon between May and August causing enormous precipitations on the Ethiopian Highlands whose summits reach heights of up to 4550 m (14,928 ft). Most of this rainwater is taken by the Blue Nile and by the Atbarah River into the Nile, while a less important amount flows through the Sobat and the White Nile into the Nile. During this short period, those rivers contribute up to ninety percent of the water of the Nile and most of the sedimentati ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cairo
Cairo ( ; ar, القاهرة, al-Qāhirah, ) is the capital of Egypt and its largest city, home to 10 million people. It is also part of the largest urban agglomeration in Africa, the Arab world and the Middle East: The Greater Cairo metropolitan area, with a population of 21.9 million, is the 12th-largest in the world by population. Cairo is associated with ancient Egypt, as the Giza pyramid complex and the ancient cities of Memphis and Heliopolis are located in its geographical area. Located near the Nile Delta, the city first developed as Fustat, a settlement founded after the Muslim conquest of Egypt in 640 next to an existing ancient Roman fortress, Babylon. Under the Fatimid dynasty a new city, ''al-Qāhirah'', was founded nearby in 969. It later superseded Fustat as the main urban centre during the Ayyubid and Mamluk periods (12th–16th centuries). Cairo has long been a centre of the region's political and cultural life, and is titled "the city of a thousa ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Fatimid Caliphate
The Fatimid Caliphate was an Ismaili Shi'a caliphate extant from the tenth to the twelfth centuries AD. Spanning a large area of North Africa, it ranged from the Atlantic Ocean in the west to the Red Sea in the east. The Fatimids, a dynasty of Arab origin, trace their ancestry to Muhammad's daughter Fatima and her husband ‘Ali b. Abi Talib, the first Shi‘a imam. The Fatimids were acknowledged as the rightful imams by different Isma‘ili communities, but also in many other Muslim lands, including Persia and the adjacent regions. Originating during the Abbasid Caliphate, the Fatimids conquered Tunisia and established the city of "Mahdia, al-Mahdiyya" ( ar, المهدية). The Ismaili dynasty ruled territories across the Mediterranean coast of Africa and ultimately made Egypt the center of the caliphate. At its height, the caliphate included – in addition to Egypt – varying areas of the Maghreb, Sudan, Sicily, the Levant, and the Hijaz. Between 902 to 909 th ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
