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Transit Of Venus
A transit of Venus takes place when Venus passes directly between the Sun and the Earth (or any other superior planet), becoming visible against (and hence obscuring a small portion of) the solar disk. During a transit, Venus is visible as a small black circle moving across the face of the Sun. Transits of Venus reoccur periodically. A pair of transits takes place eight years apart in December (Gregorian calendar) followed by a gap of 121.5 years, before another pair occurs eight years apart in June, followed by another gap, of 105.5 years. The dates advance by about two days per 243-year cycle. The periodicity is a reflection of the fact that the orbital periods of Earth and Venus are close to 8:13 and 243:395 commensurabilities. The last pairs of transits occurred on 8 June 2004 and 5–6 June 2012. The next pair of transits will occur on 10–11 December 2117 and 8 December 2125. Transits of Venus were in the past used to determine the size of the Solar System. The ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
2012 Transit Of Venus
The 2012 transit of Venus, when the planet Venus appeared as a small, dark spot passing across the face of the Sun, began at 22:09 UTC on 5 June 2012, and finished at 04:49 UTC on 6 June. Depending on the position of the observer, the exact times varied by up to ±7 minutes. Transits of Venus are among the rarest of predictable celestial phenomena and occur in pairs. Consecutive transits per pair are spaced 8 years apart, and consecutive pairs occur more than a century apart: The previous transit of Venus took place on 8 June 2004 (preceded by transits on 9 December 1874 and 6 December 1882); the next pair of transits will occur on 10–11 December 2117 and December 2125 within the 22nd century. Observations of the event The entire transit was visible from the western Pacific Ocean, northwesternmost North America, northeastern Asia, Japan, the Philippines, eastern Australia, New Zealand, and high Arctic locations including northernmost Scandinavia, and Greenland. In North ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Orbital Inclination
Orbital inclination measures the tilt of an object's orbit around a celestial body. It is expressed as the angle between a reference plane and the orbital plane or axis of direction of the orbiting object. For a satellite orbiting the Earth directly above the Equator, the plane of the satellite's orbit is the same as the Earth's equatorial plane, and the satellite's orbital inclination is 0°. The general case for a circular orbit is that it is tilted, spending half an orbit over the northern hemisphere and half over the southern. If the orbit swung between 20° north latitude and 20° south latitude, then its orbital inclination would be 20°. Orbits The inclination is one of the six orbital elements describing the shape and orientation of a celestial orbit. It is the angle between the orbital plane and the plane of reference, normally stated in degrees. For a satellite orbiting a planet, the plane of reference is usually the plane containing the planet's equator. For pla ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hesperus
In Greek mythology, Hesperus (; ) is the Evening Star, the planet Venus in the evening. A son of the dawn goddess Eos ( Roman Aurora), he is the half-brother of her other son, Phosphorus (also called Eosphorus; the "Morning Star"). Hesperus' Roman equivalent is Vesper (cf. "evening", "supper", "evening star", "west"). By one account, Hesperus' father was Cephalus, a mortal, while Phosphorus was the star god Astraeus. Other sources, however, state that Hesperus was the brother of Atlas, and thus the son of Iapetus. Variant names Hesperus is the personification of the "evening star", the planet Venus in the evening. His name is sometimes conflated with the names for his brother, the personification of the planet as the "morning star" Eosphorus (Greek , "bearer of dawn") or Phosphorus (Ancient Greek: , "bearer of light", often translated as "Lucifer" in Latin), since they are all personifications of the same planet Venus. "Heosphoros" in the Greek Septuagint and "Lucifer" in ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Phosphorus (morning Star)
Phosphorus () is the god of the planet Venus in its appearance as the Morning Star. Another Greek name for the Morning Star is "Eosphorus" (), which means "dawn-bringer". The term "eosphorus" is sometimes met in English. As an adjective, the word "phosphorus" is applied in the sense of "light-bringing" (for instance, the dawn, the god Dionysus, pine torches and the day) and "torch-bearing" as an epithet of several gods and goddesses, especially of Hecate but also of Artemis/ Diana and Hephaestus. Seasonally, Venus is the "light bringer" in the northern hemisphere, appearing most brightly in December (an optical illusion due to shorter days), signalling the "rebirth" of longer days as winter wanes. Venus The morning star is an appearance of the planet Venus, an inferior planet, meaning that its orbit lies between the Earth and the Sun. Depending on the orbital locations of both Venus and Earth, it can be seen in the eastern morning sky for an hour or so before the Sun rises ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pythagoras
Pythagoras of Samos (; BC) was an ancient Ionian Greek philosopher, polymath, and the eponymous founder of Pythagoreanism. His political and religious teachings were well known in Magna Graecia and influenced the philosophies of Plato, Aristotle, and, through them, Western philosophy. Modern scholars disagree regarding Pythagoras's education and influences, but most agree that he travelled to Croton in southern Italy around 530 BC, where he founded a school in which initiates were allegedly sworn to secrecy and lived a communal, ascetic lifestyle. In antiquity, Pythagoras was credited with mathematical and scientific discoveries, such as the Pythagorean theorem, Pythagorean tuning, the five regular solids, the theory of proportions, the sphericity of the Earth, the identity of the morning and evening stars as the planet Venus, and the division of the globe into five climatic zones. He was reputedly the first man to call himself a philosopher ("lover of wi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ancient China
The history of China spans several millennia across a wide geographical area. Each region now considered part of the Chinese world has experienced periods of unity, fracture, prosperity, and strife. Chinese civilization first emerged in the Yellow River valley, which along with the Yangtze River, Yangtze basin constitutes the geographic core of the Sinosphere, Chinese cultural sphere. China maintains a rich diversity of ethnic and linguistic people groups. The Chinese historiography, traditional lens for viewing Chinese history is the Dynasties of China, dynastic cycle: imperial dynasties rise and fall, and are ascribed certain achievements. This lens also tends to assume Chinese civilization can be traced as an unbroken thread Five thousand years of Chinese civilization, many thousands of years into the past, making it one of the Cradle of civilization, cradles of civilization. At various times, states representative of a dominant Chinese culture have directly controlled areas ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Babylonia
Babylonia (; , ) was an Ancient history, ancient Akkadian language, Akkadian-speaking state and cultural area based in the city of Babylon in central-southern Mesopotamia (present-day Iraq and parts of Kuwait, Syria and Iran). It emerged as an Akkadian-populated but Amorites, Amorite-ruled state . During the reign of Hammurabi and afterwards, Babylonia was retrospectively called "the country of Akkad" ( in Akkadian), a deliberate archaism in reference to the previous glory of the Akkadian Empire. It was often involved in rivalry with the older ethno-linguistically related state of Assyria in the north of Mesopotamia and Elam to the east in Ancient Iran. Babylonia briefly became the major power in the region after Hammurabi (floruit, fl. –1752 BC middle chronology, or –1654 BC, short chronology timeline, short chronology) created a short-lived empire, succeeding the earlier Akkadian Empire, Third Dynasty of Ur, and Old Assyrian Empire. The Babylonian Empire rapidly fell apar ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ancient Egypt
Ancient Egypt () was a cradle of civilization concentrated along the lower reaches of the Nile River in Northeast Africa. It emerged from prehistoric Egypt around 3150BC (according to conventional Egyptian chronology), when Upper and Lower Egypt were amalgamated by Menes, who is believed by the majority of List of Egyptologists, Egyptologists to have been the same person as Narmer. The history of ancient Egypt unfolded as a series of stable kingdoms interspersed by the "Periodization of ancient Egypt, Intermediate Periods" of relative instability. These stable kingdoms existed in one of three periods: the Old Kingdom of Egypt, Old Kingdom of the Early Bronze Age; the Middle Kingdom of Egypt, Middle Kingdom of the Middle Bronze Age; or the New Kingdom of Egypt, New Kingdom of the Late Bronze Age. The pinnacle of ancient Egyptian power was achieved during the New Kingdom, which extended its rule to much of Nubia and a considerable portion of the Levant. After this period, Egypt ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ancient Greek
Ancient Greek (, ; ) includes the forms of the Greek language used in ancient Greece and the classical antiquity, ancient world from around 1500 BC to 300 BC. It is often roughly divided into the following periods: Mycenaean Greek (), Greek Dark Ages, Dark Ages (), the Archaic Greece, Archaic or Homeric Greek, Homeric period (), and the Classical Greece, Classical period (). Ancient Greek was the language of Homer and of fifth-century Athens, fifth-century Athenian historians, playwrights, and Ancient Greek philosophy, philosophers. It has contributed many words to English vocabulary and has been a standard subject of study in educational institutions of the Western world since the Renaissance. This article primarily contains information about the Homeric Greek, Epic and Classical periods of the language, which are the best-attested periods and considered most typical of Ancient Greek. From the Hellenistic period (), Ancient Greek was followed by Koine Greek, which is regar ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ancient Indian
The following Outline (list), outline is provided as an overview of and topical guide to ancient India: Ancient India is the Indian subcontinent from prehistoric times to the start of Medieval India, which is typically dated (when the term is still used) to the end of the Gupta Empire around 500 Common Era, CE. General history of Ancient India An elaborate periodisation may be as follows: Pre-history (Neolithic Age) (c. 8000–3500 BCE) * Indian Pre-history Age (–3300 BCE) * Bhirrana, Bhirrana culture (7570–6200 BCE) * Mehrgarh culture () Proto-history (Bronze Age) (c. 3500–1800 BCE) * Indus Valley Civilisation (), including the "first urbanisation" * Ahar–Banas culture () * Ochre Coloured Pottery culture (–1200 BCE) * Cemetery H culture (–1300 BCE) Iron Age (c. 1800–200 BCE) *Iron Age India () **Vedic civilization () ***Black and red ware culture (–700 BCE) in Western Ganges plain ***Northern Black Polished Ware (–500 BCE)Strickland, K. M., R. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Synodic Period
The orbital period (also revolution period) is the amount of time a given astronomical object takes to complete one orbit around another object. In astronomy, it usually applies to planets or asteroids orbiting the Sun, moons orbiting planets, exoplanets orbiting other stars, or binary stars. It may also refer to the time it takes a satellite orbiting a planet or moon to complete one orbit. For celestial objects in general, the orbital period is determined by a 360° revolution of orbiting body, one body around its primary body, primary, ''e.g.'' Earth around the Sun. Periods in astronomy are expressed in units of time, usually hours, days, or years. Its reciprocal is the orbital frequency, a kind of revolution speed, revolution frequency, in units of hertz. Small body orbiting a central body According to Kepler's laws of planetary motion, Kepler's Third Law, the orbital period ''T'' of two point masses orbiting each other in a circular or elliptic orbit is: :T = 2\pi\sqrt ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sidereal Year
A sidereal year (, ; ), also called a sidereal orbital period, is the time that Earth or another planetary body takes to orbit the Sun once with respect to the fixed stars. Hence, for Earth, it is also the time taken for the Sun to return to the same position relative to Earth with respect to the fixed stars after apparently travelling once around the ecliptic. It equals for the J2000.0 epoch, or a little over 366 sidereal days. The sidereal year differs from the solar year, "the period of time required for the ecliptic longitude of the Sun to increase 360 degrees", due to the precession of the equinoxes. The sidereal year is 20 min 24.5 s longer than the mean tropical year at J2000.0 . At present, the rate of axial precession corresponds to a period of 25,772 years, so sidereal year is longer than tropical year by 1,224.5 seconds (20 min 24.5 s, ~365.24219*86400/25772). Before the discovery of the precession of the equinoxes by Hipparchus in the Hellenistic peri ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
