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Kreutz Sungrazers
The Kreutz sungrazers ( ) are a family of sungrazing comets, characterized by orbits taking them extremely close to the Sun at perihelion. They are believed to be fragments of one large comet that broke up several centuries ago and are named for German astronomer Heinrich Kreutz, who first demonstrated that they were related. A Kreutz sungrazers's aphelion is about from the Sun; these sungrazers make their way from the distant outer Solar System from a patch in the sky in Canis Major, to the inner Solar System, to their perihelion point near the Sun, and then leave the inner Solar System in their return trip to their aphelion. Several members of the Kreutz family have become great comets, occasionally visible near the Sun in the daytime sky. The most recent of these was Comet Ikeya–Seki in 1965, which may have been one of the brightest comets in the last millennium. It has been suggested that another cluster of bright Kreutz system comets may begin to arrive in the inner Sola ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sungrazing Comet
A sungrazing comet is a comet that passes extremely close to the Sun at perihelion – sometimes within a few thousand kilometres of the Sun's surface. Although small sungrazers can completely evaporate during such a close approach to the Sun, larger sungrazers can survive many perihelion passages. However, the strong evaporation and tidal forces they experience often lead to their fragmentation. Up until the 1880s, it was thought that all bright comets near the Sun were the repeated return of a single sungrazing comet. Then, German astronomer Heinrich Kreutz and American astronomer Daniel Kirkwood determined that, instead of the return of the same comet, each appearance was a different comet, but each were related to a group of comets that had separated from each other at an earlier passage near the Sun (at perihelion). Very little was known about the population of sungrazing comets until 1979 when coronagraphic observations allowed the detection of sungrazers. As of October 2 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Earth
Earth is the third planet from the Sun and the only astronomical object known to harbor life. While large volumes of water can be found throughout the Solar System, only Earth sustains liquid surface water. About 71% of Earth's surface is made up of the ocean, dwarfing Earth's polar ice, lakes, and rivers. The remaining 29% of Earth's surface is land, consisting of continents and islands. Earth's surface layer is formed of several slowly moving tectonic plates, which interact to produce mountain ranges, volcanoes, and earthquakes. Earth's liquid outer core generates the magnetic field that shapes the magnetosphere of the Earth, deflecting destructive solar winds. The atmosphere of the Earth consists mostly of nitrogen and oxygen. Greenhouse gases in the atmosphere like carbon dioxide (CO2) trap a part of the energy from the Sun close to the surface. Water vapor is widely present in the atmosphere and forms clouds that cover most of the planet. More solar e ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Naked Eye
Naked eye, also called bare eye or unaided eye, is the practice of engaging in visual perception unaided by a magnifying, light-collecting optical instrument, such as a telescope or microscope, or eye protection. Vision corrected to normal acuity using corrective lenses is still considered "naked". In astronomy, the naked eye may be used to observe celestial events and objects visible without equipment, such as conjunctions, passing comets, meteor showers, and the brightest asteroids, including 4 Vesta. Sky lore and various tests demonstrate an impressive variety of phenomena visible to the unaided eye. Basic properties Some basic properties of the human eye are: *Quick autofocus from distances of 25 cm (young people) to 50 cm (most people 50 years and older) to infinity. * Angular resolution: about 1 arcminute, approximately 0.017° or 0.0003 radians, which corresponds to 0.3 m at a 1 km distance. *Field of view (FOV): simultaneous visual percepti ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Comet Hyakutake
Comet Hyakutake (, formally designated C/1996 B2) is a comet, discovered on 31 January 1996, that passed very close to Earth in March of that year. It was dubbed the Great Comet of 1996; its passage near the Earth was one of the closest cometary approaches of the previous 200 years. Hyakutake appeared very bright in the night sky and was widely seen around the world. The comet temporarily upstaged the much anticipated Comet Hale–Bopp, which was approaching the inner Solar System at the time. Scientific observations of the comet led to several discoveries. Most surprising to cometary scientists was the first discovery of X-ray emission from a comet, believed to have been caused by ionised solar wind particles interacting with neutral atoms in the coma of the comet. The ''Ulysses'' spacecraft unexpectedly crossed the comet's tail at a distance of more than from the nucleus, showing that Hyakutake had the longest tail known for a comet. Hyakutake is a long-period comet. B ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Monthly Notices Of The Royal Astronomical Society
''Monthly Notices of the Royal Astronomical Society'' (MNRAS) is a peer-reviewed scientific journal covering research in astronomy and astrophysics. It has been in continuous existence since 1827 and publishes letters and papers reporting original research in relevant fields. Despite the name, the journal is no longer monthly, nor does it carry the notices of the Royal Astronomical Society. History The first issue of MNRAS was published on 9 February 1827 as ''Monthly Notices of the Astronomical Society of London'' and it has been in continuous publication ever since. It took its current name from the second volume, after the Astronomical Society of London became the Royal Astronomical Society (RAS). Until 1960 it carried the monthly notices of the RAS, at which time these were transferred to the newly established ''Quarterly Journal of the Royal Astronomical Society'' (1960–1996) and then to its successor journal ''Astronomy & Geophysics'' (since 1997). Until 1965, MNRAS ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Great Comet Of 371 BC
Great may refer to: Descriptions or measurements * Great, a relative measurement in physical space, see Size * Greatness, being divine, majestic, superior, majestic, or transcendent People * List of people known as "the Great" *Artel Great (born 1981), American actor Other uses * ''Great'' (1975 film), a British animated short about Isambard Kingdom Brunel * ''Great'' (2013 film), a German short film * Great (supermarket), a supermarket in Hong Kong * GReAT, Graph Rewriting and Transformation, a Model Transformation Language * Gang Resistance Education and Training Gang Resistance Education And Training, abbreviated G.R.E.A.T., provides a school-based, police officer instructed program that includes classroom instruction and various learning activities. Their intention is to teach the students to avoid gan ..., or GREAT, a school-based and police officer-instructed program * Global Research and Analysis Team (GReAT), a cybersecurity team at Kaspersky Lab *'' Great!'', a 20 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
X/1106 C1
X/1106 C1, also known as the Great Comet of 1106, was a great comet that appeared on 2 February 1106, and was observed around the world from the beginning of February through to mid-March. It was recorded by astronomers in Wales, England, Japan, Korea, China and Continental Europe. It was observed to split into many pieces, forming the Great Comet of 1882 and Comet Ikeya–Seki as well as over 4000 small sungrazing comets observed by the SOHO space telescope. It is a member of the Kreutz Group, known as Subfragment I, a split from an earlier large (~150 km) comet that progressively fragmented under the influence of the Sun. Observations Britain A brief note in the Welsh manuscript known as the ''Brut y Tywysogion'' reads: 1106 Yn y vlwydyn honno y gwelat seren anryued y gwelet yn anuon paladyr oheuni yn ol y chefyn ac o prafter colofyn y veint a diruawr oleuat idaw, yn darogan yr hyn a vei rac llaw: kanys Henri, amherawdyr Rufein, gwedy diruawryon vudugolyaetheu a chrefud ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Longitude Of Ascending Node
The longitude of the ascending node (☊ or Ω) is one of the orbital elements used to specify the orbit of an object in space. It is the angle from a specified reference direction, called the ''origin of longitude'', to the direction of the ascending node, as measured in a specified reference plane. The ascending node is the point where the orbit of the object passes through the plane of reference, as seen in the adjacent image. Commonly used reference planes and origins of longitude include: * For geocentric orbits, Earth's equatorial plane as the reference plane, and the First Point of Aries as the origin of longitude. In this case, the longitude is also called the right ascension of the ascending node (RAAN). The angle is measured eastwards (or, as seen from the north, counterclockwise) from the First Point of Aries to the node. [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Inclination
Orbital inclination measures the tilt of an object's orbit around a celestial body. It is expressed as the angle between a Plane of reference, reference plane and the orbital plane or Axis of rotation, 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 degree (angle), degrees. For a satellite orbiting a planet, the plane of reference is usually ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Comet Pereyra
Comet Pereyra (formal designations: C/1963 R1, 1963 V, and 1963e) was a bright comet which appeared in 1963. It was a member of the Kreutz Sungrazers, a group of comets which pass extremely close to the Sun. Discovery The comet was first seen on 14 September 1963, by Z.M. Pereyra of Cordoba observatory in Argentina. British observer George Alcock later reported that he had observed a thin pencil-like beam of light low in the sky on 12 September, which may have been the comet's tail. It was bright, at apparent magnitude 2, and had a short tail about 1 degree long. Over the next few days, the comet faded rapidly, having evidently already passed perihelion, although its tail grew to about 10° in length by late September. During its short period of naked eye visibility it was widely observed throughout the southern hemisphere. Orbital studies As the comet receded from the Sun, orbital studies showed that Pereyra had been a sungrazing comet, passing just 60,000 kilometre ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Great Southern Comet Of 1887
The Great Southern Comet of 1887, or C/1887 B1 using its International Astronomical Union (IAU) designation, was a bright comet seen from the Southern Hemisphere during January 1887. Later calculations indicated it to be part of the Kreutz Sungrazing group. A curious feature of the comet was that few, if any observations were made of a cometary head or nucleus. As a result, some older astronomical texts refer to it as the "Headless Wonder".Bortle, JThe Bright Comet Chronicles ''International Comet Quarterly'', 1998 Discovery The comet was officially discovered by astronomer John Macon Thome at Córdoba, Argentina, on January 19, at which point it was located in the constellation Grus.Kronk, G. W. ''Cometography'', v2, CUP, 2003, p.588 However, correspondence from William Henry Finlay suggests that it may also have been seen from Blauwberg, South Africa, on January 18. At the time of discovery the comet had already passed perihelion a week earlier, and its closest approa ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Great Comet Of 1882
The Great Comet of 1882 formally designated C/1882 R1, 1882 II, and 1882b, was a comet which became very bright in September 1882. It was a member of the Kreutz Sungrazers, a family of comets which pass within of the Sun's photosphere at perihelion. The comet was bright enough to be visible next to the Sun in the daytime sky at its perihelion. Discovery The comet appeared in the morning skies of September 1882. Reports suggest that it was first seen as early as 1 September 1882, from the Cape of Good Hope as well as the Gulf of Guinea, and over the next few days many observers in the southern hemisphere reported the new comet. The first astronomer to record observations of the comet was W. H. Finlay, the Chief Assistant at the Royal Observatory in Cape Town, South Africa. Finlay's observation on 7 September at 16h GMT was also an independent discovery, and he reported that the comet had an apparent magnitude of about 3, and a tail about a degree in length. The comet brigh ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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