Cosmology (from Greek κοσμολογία - κόσμος, kosmos, "universe"; and -λογία, -logia, "study"), in strict usage, refers to the study of the Universe in its totality as it now is (or at least as it can be observed now), and by extension, humanity's place in it. Though the word cosmology is recent (first used in 1730 in Christian Wolff's Cosmologia Generalis), the study of the universe has a long history involving science, philosophy, esotericism, and religion. (See Cosmogony for the study of origins of the Universe.)
In recent times, physics and astrophysics have played a central role in shaping the understanding of the universe through scientific observation and experiment; or what is known as physical cosmology shaped through both mathematics and observation in the analysis of the whole universe. In other words, in this discipline, which focuses on the universe as it exists on the largest scale and at the earliest moments, it is generally understood to begin with the Big Bang (possibly combined with cosmic inflation) – an expansion of space from which the universe itself is thought to have emerged ~13.7±0.2×109 (13.7 billion) years ago.
Sunday, November 28, 2010
Intergalactic space
Intergalactic space is the physical space between galaxies. Generally free of dust and debris, intergalactic space is very close to a total vacuum. The space between galaxy clusters, called the voids, is probably nearly empty. Some theories put the average density of the Universe as the equivalent of one hydrogen atom per cubic meter. The density of the universe, however, is clearly not uniform; it ranges from relatively high density in galaxies (including very high density in structures within galaxies, such as planets, stars, and black holes) to conditions in vast voids that have much lower density than the universe's average.
Galaxy
A galaxy is a massive, gravitationally bound system that consists of stars and stellar remnants, an interstellar medium of gas dust, and an important but poorly understood component tentatively dubbed dark matter.The name is from the Greek root galaxias [γαλαξίας], literally meaning "milky", a reference to the Milky Way galaxy. Typical galaxies range from dwarfs with as few as ten million (107) stars, up to giants with a hundred trillion (1014) stars, all orbiting the galaxy's center of mass. Galaxies may contain many star systems, star clusters, and various interstellar clouds. The Sun is one of the stars in the Milky Way galaxy; the Solar System includes the Earth and all the other objects that orbit the Sun.
Astronomy
Astronomy is a natural science that deals with the study of celestial objects (such as stars, planets, comets, nebulae, star clusters and galaxies) and phenomena that originate outside the Earth's atmosphere (such as the cosmic background radiation). It is concerned with the evolution, physics, chemistry, meteorology, and motion of celestial objects, as well as the formation and development of the universe.
Astronomy is one of the oldest sciences. Prehistoric cultures left behind astronomical artifacts such as the Egyptian monuments and Stonehenge, and early civilizations such as the Babylonians, Greeks, Chinese, Indians, and Maya performed methodical observations of the night sky. However, the invention of the telescope was required before astronomy was able to develop into a modern science. Historically, astronomy has included disciplines as diverse as astrometry, celestial navigation, observational astronomy, the making of calendars, and even astrology, but professional astronomy is nowadays often considered to be synonymous with astrophysics.
Astronomy is one of the oldest sciences. Prehistoric cultures left behind astronomical artifacts such as the Egyptian monuments and Stonehenge, and early civilizations such as the Babylonians, Greeks, Chinese, Indians, and Maya performed methodical observations of the night sky. However, the invention of the telescope was required before astronomy was able to develop into a modern science. Historically, astronomy has included disciplines as diverse as astrometry, celestial navigation, observational astronomy, the making of calendars, and even astrology, but professional astronomy is nowadays often considered to be synonymous with astrophysics.
almanac
An almanac (also spelled almanack and almanach) is an annual publication that includes information such as weather forecasts, farmers' planting dates, astronomical information, and tide tables, containing tabular information in a particular field or fields often arranged according to the calendar etc. Astronomical data and various statistics are also found in almanacs, such as the times of the rising and setting of the sun and moon, eclipses, hours of full tide, stated festivals of churches, terms of courts, lists of all types, timelines, and more.
The earliest documented use of the word in any language is in 1267 by Roger Bacon. One etymology expert says: "The ultimate source of the word is obscure. Its first syllable, al-, and its general relevance to medieval science and technology, strongly suggest an Arabic origin, but no convincing candidate has been found." Another expert similarly says of Almanac: "First seen in Roger Bacon. Apparently from Spanish Arabic, al-manakh, but this is not an Arabic word [interpret: this is not a word found in Arabic texts].. The word remains a puzzle."
The earliest documented use of the word in any language is in 1267 by Roger Bacon. One etymology expert says: "The ultimate source of the word is obscure. Its first syllable, al-, and its general relevance to medieval science and technology, strongly suggest an Arabic origin, but no convincing candidate has been found." Another expert similarly says of Almanac: "First seen in Roger Bacon. Apparently from Spanish Arabic, al-manakh, but this is not an Arabic word [interpret: this is not a word found in Arabic texts].. The word remains a puzzle."
hoax
The British philologist Robert Nares (1753–1829) says that the word hoax was coined in the late 18th century as a contraction of the verb hocus, which means "to cheat", "to impose upon" or "to befuddle often with drugged liquor". Hocus is a shortening of the magic incantation hocus pocus, which in turn is a contraction of the phrase Hocus pocus, tontus talontus, vade celeriter jubeo, mentioned in Thomas Ady's 1656 book A candle in the dark, or a treatise on the nature of witches and witchcraft. According to the book, the Latin-like gibberish phrase was uttered by a conjuror to distract his audience from his sleight of hand.
The term hoax is occasionally used in reference to urban legends and rumors, but the folklorist Jan Harold Brunvand argues that most of them lack evidence of deliberate creations of falsehood and are passed along in good faith by believers or as jokes, so the term should be used for only those with a probable conscious attempt to deceive.As for the closely related terms practical joke and prank, Brunvand states that although there are instances they overlap, hoax tends to indicate "relatively complex and large-scale fabrications" and includes deceptions that go beyond the merely playful and "cause material loss or harm to the victim".
P. T. Barnum's Fiji mermaid (1842)
According to Professor Lynda Walsh of the University of Nevada, Reno, some hoaxes—such as the Great Stock Exchange Fraud of 1814, labeled as a hoax by contemporary commentators—are financial in nature, and successful hoaxers—such as P. T. Barnum, whose Fiji mermaid contributed to his wealth—often acquire monetary gain or fame through their fabrications, so the distinction between hoax and fraud is not necessarily clear. Alex Boese, the creator of the Museum of Hoaxes, states that the only distinction between them is the reaction of the public, because a fraud can be classified as a hoax when its method of acquiring financial gain creates a broad public impact or captures the imagination of the masses.
The term hoax is occasionally used in reference to urban legends and rumors, but the folklorist Jan Harold Brunvand argues that most of them lack evidence of deliberate creations of falsehood and are passed along in good faith by believers or as jokes, so the term should be used for only those with a probable conscious attempt to deceive.As for the closely related terms practical joke and prank, Brunvand states that although there are instances they overlap, hoax tends to indicate "relatively complex and large-scale fabrications" and includes deceptions that go beyond the merely playful and "cause material loss or harm to the victim".
P. T. Barnum's Fiji mermaid (1842)
According to Professor Lynda Walsh of the University of Nevada, Reno, some hoaxes—such as the Great Stock Exchange Fraud of 1814, labeled as a hoax by contemporary commentators—are financial in nature, and successful hoaxers—such as P. T. Barnum, whose Fiji mermaid contributed to his wealth—often acquire monetary gain or fame through their fabrications, so the distinction between hoax and fraud is not necessarily clear. Alex Boese, the creator of the Museum of Hoaxes, states that the only distinction between them is the reaction of the public, because a fraud can be classified as a hoax when its method of acquiring financial gain creates a broad public impact or captures the imagination of the masses.
Tuesday, November 2, 2010
ththe social network
a new movie called thesocialnetwork is released and running successfully in los angeles,usa,it has grossed more than 50 million$ and is my favorite movie of all time
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