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A megacryometeor is a very large chunk of ice which, despite sharing many textural, hydro-chemical and isotopic features detected in large hailstones, is formed under unusual atmospheric conditions which clearly differ from those of the cumulonimbus cloud scenario (i.e. clear-sky conditions). They are sometimes called huge hailstones, but do not need to form under thunderstorm conditions. Jesús Martínez-Frías, a planetary geologist and astrobiologist at Institute of Geosciences (Spanish : Instituto de Geociencias, IGEO) in the Spanish National Research Council (Spanish : Consejo Superior de Investigaciones Científicas, CSIC) in Madrid, pioneered research into megacryometeors in January 2000 after ice chunks weighing up to 6.6 pounds (3.0 kg) rained on Spain out of cloudless skies for ten days.
Ice is water frozen into a solid state. Depending on the presence of impurities such as particles of soil or bubbles of air, it can appear transparent or a more or less opaque bluish-white color.
Hail is a form of solid precipitation. It is distinct from ice pellets, though the two are often confused. It consists of balls or irregular lumps of ice, each of which is called a hailstone. Ice pellets fall generally in cold weather while hail growth is greatly inhibited during cold surface temperatures.
Cumulonimbus is a dense, towering vertical cloud, forming from water vapor carried by powerful upward air currents. If observed during a storm, these clouds may be referred to as thunderheads. Cumulonimbus can form alone, in clusters, or along cold front squall lines. These clouds are capable of producing lightning and other dangerous severe weather, such as tornadoes. Cumulonimbus progress from overdeveloped cumulus congestus clouds and may further develop as part of a supercell. Cumulonimbus is abbreviated Cb.
More than 50 megacryometeors have been recorded since the year 2000. They vary in mass between 0.5 kilograms (1.1 lb) to several tens of kilograms. One in Brazil weighed in at more than 50 kilograms (110 lb). Chunks about 2 m (6 ft 7 in) in size fell in Scotland on 13 August 1849.
Brazil, officially the Federative Republic of Brazil, is the largest country in both South America and Latin America. At 8.5 million square kilometers and with over 208 million people, Brazil is the world's fifth-largest country by area and the fifth most populous. Its capital is Brasília, and its most populated city is São Paulo. The federation is composed of the union of the 26 states, the Federal District, and the 5,570 municipalities. It is the largest country to have Portuguese as an official language and the only one in the Americas; it is also one of the most multicultural and ethnically diverse nations, due to over a century of mass immigration from around the world.
The process that creates megacryometeors is not completely understood, mainly with respect to the atmospheric dynamics necessary to produce them. They may have a similar mechanism of formation to that leading to production of hailstones.Scientific studies show that their composition matches normal tropospheric rainwater for the areas in which they fall. In addition, megacryometeors display textural variations of the ice and hydro-chemical and isotopic heterogeneity, which evidence a complex formation process in the atmosphere. It is known that they do not form from airplane toilet leakage because the large chunks of ice that occasionally do fall from airliners are distinctly blue due to the disinfectant used.
Rain is liquid water in the form of droplets that have condensed from atmospheric water vapor and then become heavy enough to fall under gravity. Rain is a major component of the water cycle and is responsible for depositing most of the fresh water on the Earth. It provides suitable conditions for many types of ecosystems, as well as water for hydroelectric power plants and crop irrigation.
An atmosphere is a layer or a set of layers of gases surrounding a planet or other material body, that is held in place by the gravity of that body. An atmosphere is more likely to be retained if the gravity it is subject to is high and the temperature of the atmosphere is low.
Disinfectants are antimicrobial agents that are applied to the surface of non-living objects to destroy microorganisms that are living on the objects. Disinfection does not necessarily kill all microorganisms, especially resistant bacterial spores; it is less effective than sterilization, which is an extreme physical and/or chemical process that kills all types of life. Disinfectants are different from other antimicrobial agents such as antibiotics, which destroy microorganisms within the body, and antiseptics, which destroy microorganisms on living tissue. Disinfectants are also different from biocides — the latter are intended to destroy all forms of life, not just microorganisms. Disinfectants work by destroying the cell wall of microbes or interfering with their metabolism.
Some have speculated that these ice chunks must have fallen from aircraft fuselages −10 to −20 °C (14 to −4 °F). They are sometimes confused with meteors because they can leave small impact craters.after plain water ice accumulating on those aircraft through normal atmospheric conditions has simply broken loose. However, similar events occurred prior to the invention of aircraft. Studies indicate that fluctuations in tropopause, associated with hydration of the lower stratosphere and stratospheric cooling, can be related to their formation. A detailed micro-Raman spectroscopic study made it possible to place the formation of the megacryometeors within a particular range of temperatures:
The tropopause is the boundary in the Earth's atmosphere between the troposphere and the stratosphere. It is a thermodynamic gradient stratification layer, marking the end of troposphere. It lies, on average, at 17 kilometres (11 mi) above equatorial regions, and above 9 kilometres (5.6 mi) over the polar regions.
The stratosphere is the second major layer of Earth's atmosphere, just above the troposphere, and below the mesosphere. The stratosphere is stratified (layered) in temperature, with warmer layers higher and cooler layers closer to the Earth; this increase of temperature with altitude is a result of the absorption of the Sun's ultraviolet radiation by the ozone layer. This is in contrast to the troposphere, near the Earth's surface, where temperature decreases with altitude. The border between the troposphere and stratosphere, the tropopause, marks where this temperature inversion begins. Near the equator, the stratosphere starts at as high as 20 km, around 10 km at midlatitudes, and at about 7 km at the poles. Temperatures range from an average of −51 °C near the tropopause to an average of −15 °C near the mesosphere. Stratospheric temperatures also vary within the stratosphere as the seasons change, reaching particularly low temperatures in the polar night (winter). Winds in the stratosphere can far exceed those in the troposphere, reaching near 60 m/s in the Southern polar vortex.
An impact crater is an approximately circular depression in the surface of a planet, moon, or other solid body in the Solar System or elsewhere, formed by the hypervelocity impact of a smaller body. In contrast to volcanic craters, which result from explosion or internal collapse, impact craters typically have raised rims and floors that are lower in elevation than the surrounding terrain. Impact craters range from small, simple, bowl-shaped depressions to large, complex, multi-ringed impact basins. Meteor Crater is a well-known example of a small impact crater on Earth.
The Eocene Epoch, lasting from 13C in the atmosphere was exceptionally low in comparison with the more common isotope 12C. The end is set at a major extinction event called the Grande Coupure or the Eocene–Oligocene extinction event, which may be related to the impact of one or more large bolides in Siberia and in what is now Chesapeake Bay. As with other geologic periods, the strata that define the start and end of the epoch are well identified, though their exact dates are slightly uncertain., is a major division of the geologic timescale and the second epoch of the Paleogene Period in the Cenozoic Era. The Eocene spans the time from the end of the Paleocene Epoch to the beginning of the Oligocene Epoch. The start of the Eocene is marked by a brief period in which the concentration of the carbon isotope
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Cirrus is a genus of atmospheric cloud generally characterized by thin, wispy strands, giving the type its name from the Latin word cirrus, meaning a ringlet or curling lock of hair. This cloud can form at any altitude between 16,500 ft and 45,000 ft above sea level. The strands of cloud sometimes appear in tufts of a distinctive form referred to by the common name of "mares' tails".
Water vapor, water vapour or aqueous vapor is the gaseous phase of water. It is one state of water within the hydrosphere. Water vapor can be produced from the evaporation or boiling of liquid water or from the sublimation of ice. Unlike other forms of water, water vapor is invisible. Under typical atmospheric conditions, water vapor is continuously generated by evaporation and removed by condensation. It is less dense than air and triggers convection currents that can lead to clouds.
A mushroom cloud is a distinctive pyrocumulus mushroom-shaped cloud of debris/smoke and usually condensed water vapor resulting from a large explosion. The effect is most commonly associated with a nuclear explosion, but any sufficiently energetic detonation or deflagration will produce the same effect. They can be caused by powerful conventional weapons, like thermobaric weapons, including the ATBIP and GBU-43/B Massive Ordnance Air Blast. Some volcanic eruptions and impact events can produce natural mushroom clouds.
Cloud physics is the study of the physical processes that lead to the formation, growth and precipitation of atmospheric clouds. These aerosols are found in the troposphere, stratosphere, and mesosphere, which collectively make up the greatest part of the homosphere. Clouds consist of microscopic droplets of liquid water, tiny crystals of ice, or both. Cloud droplets initially form by the condensation of water vapor onto condensation nuclei when the supersaturation of air exceeds a critical value according to Köhler theory. Cloud condensation nuclei are necessary for cloud droplets formation because of the Kelvin effect, which describes the change in saturation vapor pressure due to a curved surface. At small radii, the amount of supersaturation needed for condensation to occur is so large, that it does not happen naturally. Raoult's law describes how the vapor pressure is dependent on the amount of solute in a solution. At high concentrations, when the cloud droplets are small, the supersaturation required is smaller than without the presence of a nucleus.
Polar stratospheric clouds (PSCs), also known as nacreous clouds, are clouds in the winter polar stratosphere at altitudes of 15,000–25,000 m (49,000–82,000 ft). They are best observed during civil twilight, when the Sun is between 1 and 6 degrees below the horizon, as well as in winter and in more northerly latitudes. They are implicated in the formation of ozone holes. The effects on ozone depletion arise because they support chemical reactions that produce active chlorine which catalyzes ozone destruction, and also because they remove gaseous nitric acid, perturbing nitrogen and chlorine cycles in a way which increases ozone depletion.
Santiago Martínez Delgado (1906–1954) was a Colombian painter, sculptor, art historian and writer. He established a reputation as a prominent muralist during the 1940s and is also known for his watercolors, oil paintings, illustrations and woodcarvings.
The Arthur L. Day Prize and Lectureship is awarded by the U.S. National Academy of Sciences "to a scientist making new contributions to the physics of the Earth whose four to six lectures would prove a solid, timely, and useful addition to the knowledge and literature in the field." The prize was established by the physicist Arthur L. Day.
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The term Middle Miocene disruption, alternatively the Middle Miocene extinction or Middle Miocene extinction peak, refers to a wave of extinctions of terrestrial and aquatic life forms that occurred around the middle of the Miocene, roughly 14 million years ago, during the Langhian stage of the Miocene. This era of extinction is believed to be caused by a relatively steady period of cooling that resulted in the growth of ice sheet volumes globally, and the reestablishment of the ice of the East Antarctic Ice Sheet (EAIS). Cooling that led to the Middle Miocene disruption has been attributed to CO2 being pulled out of the atmosphere by organic material before becoming caught in different locations like the Monterey Formation. Other ideas as to the cause for this cooling are connected to changes in oceanic and atmospheric circulation. This period was preceded by the Miocene Climatic Optimum, a period of relative warmth from 18 to 14 Ma.
The atmosphere of Titan is the layer of gases surrounding Titan, the largest moon of Saturn. It is the only thick atmosphere of a natural satellite in the Solar System.
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The Allende meteorite is the largest carbonaceous chondrite ever found on Earth. The fireball was witnessed at 01:05 on February 8, 1969, falling over the Mexican state of Chihuahua. After breaking up in the atmosphere, an extensive search for pieces was conducted and over 2 tonnes (tons) of meteorite were recovered. The availability of large quantities of samples of the scientifically-important chondrite class has enabled numerous investigations by a large number of scientists; it is often described as "the best-studied meteorite in history." The Allende meteorite has abundant, large calcium-aluminium-rich inclusions, which are among the oldest objects formed in the Solar System.
John Hoffman is a space scientist who developed instruments for Apollo 15, Apollo 16, Apollo 17, the Pioneer Venus project, and Giotto mission. He also designed the mass spectrometer for the Phoenix Mars Lander mission in May 2008. He is currently a professor of physics at the University of Texas at Dallas.
Stratospheric sulfur aerosols are sulfur-rich particles which exist in the stratosphere region of the Earth's atmosphere. The layer of the atmosphere in which they exist is known as the Junge layer, or simply the stratospheric aerosol layer. These particles consist of a mixture of sulfuric acid and water. They are created naturally, such as by photochemical decomposition of sulfur-containing gases, e.g. carbonyl sulfide. When present in high levels, e.g. after a strong volcanic eruption such as Mount Pinatubo, they produce a cooling effect, by reflecting sunlight, and by modifying clouds as they fall out of the stratosphere. This cooling may persist for a few years before the particles fall out.
The ability of stratospheric sulfate aerosols to create a global dimming effect has made them a possible candidate for use in solar radiation management climate engineering projects to limit the effect and impact of climate change due to rising levels of greenhouse gases. Delivery of precursor sulfide gases such as sulfuric acid, hydrogen sulfide or sulfur dioxide by artillery, aircraft and balloons has been proposed. It presently appears that this proposed method could counter most climatic changes, take effect rapidly, have very low direct implementation costs, and be reversible in its direct climatic effects; although other effects are possible.
Raman Laser Spectrometer (RLS) is a miniature Raman spectrometer that is part of the science payload on board the European Space Agency'sRosalind Franklin rover, tasked to search for biosignatures and biomarkers on Mars. The rover is planned to be launched in July 2020 and land on Mars in March 2021.
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