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Younger Dryas Impact Hypothesis
The Younger Dryas impact hypothesis (YDIH) proposes that the onset of the Younger Dryas (YD) cool period (stadial) at the end of the Last Glacial Period, around 12,900 years ago was the result of some kind of cosmic event with specific details varying between publications. The hypothesis is widely rejected by relevant experts. It is influenced by creationism, and has been compared to cold fusion by its critics due to the lack of reproducibility of results. It is an alternative to the long-standing and widely accepted explanation that the Younger Dryas was caused by a significant reduction in, or shutdown of the Shutdown of thermohaline circulation, North Atlantic Conveyor due to a sudden influx of freshwater from Lake Agassiz and deglaciation in North America.: "The prevailing hypothesis is that the cooling and stratification of the North Atlantic Ocean were a consequence of massive ice sheet discharge of meltwater and icebergs and resulted in reduction or cessation of the North Atl ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Younger Dryas
The Younger Dryas (YD, Greenland Stadial GS-1) was a period in Earth's geologic history that occurred circa 12,900 to 11,700 years Before Present (BP). It is primarily known for the sudden or "abrupt" cooling in the Northern Hemisphere, when the North Atlantic Ocean cooled and annual air temperatures decreased by ~ over North America, in Europe and up to in Greenland, in a few decades. Cooling in Greenland was particularly rapid, taking place over just 3 years or less. At the same time, the Southern Hemisphere experienced warming. This period ended as rapidly as it began, with dramatic warming over ~50 years, the transition from the glacial Pleistocene epoch into the current Holocene. The Younger Dryas onset was not fully synchronized; in the tropics, the cooling was spread out over several centuries, and the same was true of the early-Holocene warming. Even in the Northern Hemisphere, temperature change was highly seasonal, with much colder winters, cooler springs, yet no cha ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Tunguska Event
The Tunguska event was a large explosion of between 3 and 50 TNT equivalent, megatons that occurred near the Podkamennaya Tunguska River in Yeniseysk Governorate (now Krasnoyarsk Krai), Russia, on the morning of 30 June 1908. The explosion over the sparsely populated East Siberian taiga felled an estimated 80 million trees over an area of of forest, and eyewitness accounts suggest up to three people may have died. The explosion is attributed to a meteor air burst, the atmospheric explosion of a stony asteroid about wide. The asteroid approached from the east-south-east, probably with a relatively high speed of about . Though the incident is classified as an impact event, the object is thought to have exploded at an altitude of rather than hitting the Earth's surface, leaving no impact crater. The Tunguska event is the largest impact event on Earth in recorded history, though List of impact craters on Earth, much larger impacts are believed to have occurred in prehistoric ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Fullerene
A fullerene is an allotropes of carbon, allotrope of carbon whose molecules consist of carbon atoms connected by single and double bonds so as to form a closed or partially closed mesh, with fused rings of five to six atoms. The molecules may have hollow sphere- and ellipsoid-like forms, cylinder (geometry), tubes, or other shapes. Fullerenes with a closed mesh topology are informally denoted by their empirical formula C''n'', often written C''n'', where ''n'' is the number of carbon atoms. However, for some values of ''n'' there may be more than one isomer. The family is named after buckminsterfullerene (C60), the most famous member, which in turn is named after Buckminster Fuller. The closed fullerenes, especially C60, are also informally called buckyballs for their resemblance to the standard ball (association football), ball of association football. Nested closed fullerenes have been named bucky onions. Cylindrical fullerenes are also called carbon nanotubes or buckytubes ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Palladium
Palladium is a chemical element; it has symbol Pd and atomic number 46. It is a rare and lustrous silvery-white metal discovered in 1802 by the English chemist William Hyde Wollaston. He named it after the asteroid Pallas (formally 2 Pallas), which was itself named after the epithet of the Greek goddess Athena, acquired by her when she slew Pallas. Palladium, platinum, rhodium, ruthenium, iridium and osmium form together a group of elements referred to as the platinum group metals (PGMs). They have similar chemical properties, but palladium has the lowest melting point and is the least dense of them. More than half the supply of palladium and its congener platinum is used in catalytic converters, which convert as much as 90% of the harmful gases in automobile exhaust (hydrocarbons, carbon monoxide, and nitrogen dioxide) into nontoxic substances (nitrogen, carbon dioxide and water vapor). Palladium is also used in electronics, dentistry, medicine, hydrogen purification ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Platinum
Platinum is a chemical element; it has Symbol (chemistry), symbol Pt and atomic number 78. It is a density, dense, malleable, ductility, ductile, highly unreactive, precious metal, precious, silverish-white transition metal. Its name originates from Spanish language, Spanish , a diminutive of "silver". Platinum is a member of the platinum group of elements and group 10 element, group 10 of the periodic table of elements. It has six naturally occurring isotopes. It is one of the Abundance of elements in Earth's crust, rarer elements in Earth's crust, with an average abundance of approximately 5 microgram, μg/kg, making platinum about 30 times rarer than gold. It occurs in some nickel and copper ores along with some Native element mineral, native deposits, with 90% of current production from deposits across Russia's Ural Mountains, Colombia, the Sudbury Basin, Sudbury basin of Canada, and a large reserve in South Africa. Because of its scarcity in Earth's crust, only a f ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Iridium
Iridium is a chemical element; it has the symbol Ir and atomic number 77. This very hard, brittle, silvery-white transition metal of the platinum group, is considered the second-densest naturally occurring metal (after osmium) with a density of as defined by experimental X-ray crystallography. 191Ir and 193Ir are the only two naturally occurring isotopes of iridium, as well as the only stable isotopes; the latter is the more abundant. It is one of the most corrosion-resistant metals, even at temperatures as high as . Iridium was discovered in 1803 in the acid-insoluble residues of platinum ores by the English chemist Smithson Tennant. The name ''iridium'', derived from the Greek word ''iris'' (rainbow), refers to the various colors of its compounds. Iridium is one of the rarest elements in Earth's crust, with an estimated annual production of only in 2023. The dominant uses of iridium are the metal itself and its alloys, as in high-performance spark plugs, crucibles for ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Microspherulite
Microspherulites are microscopic spherical particles with diameter less than two mm, usually in the 100 micrometre range, mainly consisting of mineral material (the Greek ''litos'' means "stone"). Only bodies created by natural physico-chemical processes, with no contribution of either biological (in aqueous depositional environment, sedimentary environments this contribution is possible) or human activity, are considered to be microspherulites. Generally speaking, the common feature (sphericity) indicates that each sphere represents an internal equilibrium of forces within a fluid medium (water, air). Classification Several types of these forms are found in nature. Depending on the formational environment, microspherulites can be classed as oolites, micrometeorites, impact spherulites, iberulites, pisolites, Meteorite, aerolites, chondrules, biolites, pellets, bubbles, or carbonaceous microspherules. Aqueous environment * Oolites are internally structured spheres, composed ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Nanodiamonds
Nanodiamonds, or diamond nanoparticles, are diamonds with a size below 100 nanometers. They can be produced by impact events such as an explosion or meteoritic impacts. Because of their inexpensive, large-scale synthesis, potential for surface functionalization, and high biocompatibility, nanodiamonds are widely investigated as a potential material in biological and electronic applications and quantum engineering. History In 1963, Soviet scientists at the All-Union Research Institute of Technical Physics noticed that nanodiamonds were created by nuclear explosions that used carbon-based trigger explosives. Structure and composition There are three main aspects in the structure of diamond nanoparticles to be considered: the overall shape, the core, and the surface. Through multiple diffraction experiments, it has been determined that the overall shape of diamond nanoparticles is either spherical or elliptical. At the core of diamond nanoparticles lies a diamond cage, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Science News
''Science News'' (''SN'') is an American monthly magazine devoted to articles about new scientific and technical developments, typically gleaned from recent scientific and technical journals. The periodical has been described as having a scope across "all sciences" and as having "up to date" coverage. History ''Science News'' has been published since 1922 by the Society for Science & the Public, a non-profit organization founded by E. W. Scripps in 1920. American chemist Edwin Slosson served as the publication's first editor. From 1922 to 1966, it was called ''Science News Letter''. The title was changed to ''Science News'' with the March 12, 1966, issue (vol. 89, no. 11). Tom Siegfried was the editor from 2007 to 2012. In 2012, Siegfried stepped down, and Eva Emerson became the Editor in Chief of the magazine. In 2017, Eva Emerson stepped down to become the editor of a new digital magazine, ''Annual Reviews''. On February 1, 2018, Nancy Shute became the Editor in Chief of ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Marker Horizon
Marker horizons (also referred to as chronohorizons, key beds or marker beds) are stratigraphic units of the same age and of such distinctive composition and appearance, that, despite their presence in separate geographic locations, there is no doubt about their being of equivalent age (isochronous) and of common origin. Such clear markers facilitate the correlation of strata, and used in conjunction with fossil floral and faunal assemblages and paleomagnetism, permit the mapping of land masses and bodies of water throughout the history of the earth. They usually consist of a relatively thin layer of sedimentary rock that is readily recognized on the basis of either its distinct physical characteristics or fossil content and can be mapped over a very large geographic area.Neuendorf, K.K.E., J.P. Mehl, Jr., and J.A. Jackson, J.A., eds. (2005) ''Glossary of Geology'' (5th ed.). Alexandria, Virginia, American Geological Institute. 779 pp. As a result, a key bed is useful for correlati ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Retraction In Academic Publishing
In academic publishing, a retraction is a mechanism by which a published paper in an academic journal is flagged for being seriously flawed to the extent that their results and conclusions can no longer be relied upon. Retracted articles are not removed from the published literature but marked as retracted. In some cases it may be necessary to remove an article from publication, such as when the article is clearly defamatory, violates personal privacy, is the subject of a court order, or might pose a serious health risk to the general public. Although the majority of retractions are linked to scientific misconduct, they are often cited as evidence of the self-correcting nature of science. However, some scholars argue this view is misleading, describing it as a myth. Procedure A retraction may be initiated by the editors of a journal, or by the author(s) of the papers (or their institution). Retractions are typically accompanied by a retraction notice written by the editors or ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Scientific Reports
''Scientific Reports'' is a peer-reviewed open-access scientific mega journal published by Nature Portfolio, covering all areas of the natural sciences. The journal was established in 2011. The journal states that their aim is to assess solely the scientific validity of a submitted paper, rather than its perceived importance, significance, or impact. In September 2016, the journal became the largest in the world by number of articles, overtaking '' PLOS ONE''. Abstracting and indexing The journal is abstracted and indexed in the Chemical Abstracts Service, the Science Citation Index Expanded, and selectively in Index Medicus/MEDLINE/PubMed. According to the ''Journal Citation Reports'', the journal has a 2023 impact factor 3.8. Reviewing policy The ''Guide to Referees'' states that to be published, "a paper must be scientifically valid and technically sound in methodology and analysis", and reviewers have to ensure manuscripts "are not assessed based on their perceived impor ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
