Active Regions
An active region is a temporary region in the Sun's atmosphere characterized by a strong and complex magnetic field. They are often associated with sunspots and are commonly the source of violent eruptions such as coronal mass ejections and solar flares. The number and location of active regions on the solar disk at any given time is dependent on the solar cycle. Region numbers Newly observed active regions on the solar disk are assigned 4-digit region numbers by the Space Weather Prediction Center (SWPC) on the day following the initial observation. The region number assigned to a particular active region is one added to the previously assigned number. For example, the first observation of active region 8090, or AR8090, was followed by AR8091. According to the SWPC, a number is assigned to a region if it meets at least one of the following criteria: # It contains a sunspot group of class C or larger based on the Modified Zurich Class sunspot classification system. # It contain ...
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Stellar Atmosphere
The stellar atmosphere is the outer region of the volume of a star, lying above the stellar core, radiation zone and convection zone. Overview The stellar atmosphere is divided into several regions of distinct character: * The photosphere, which is the atmosphere's lowest and coolest layer, is normally its only visible part. Light escaping from the surface of the star stems from this region and passes through the higher layers. The Sun's photosphere has a temperature in the 5,770  K to 5,780 K range. Starspots, cool regions of disrupted magnetic field lie on the photosphere. * Above the photosphere lies the chromosphere. This part of the atmosphere first cools down and then starts to heat up to about 10 times the temperature of the photosphere. * Above the chromosphere lies the transition region, where the temperature increases rapidly on a distance of only around 100 km. * The outermost part of the stellar atmosphere is the corona, a tenuous plasma which has a tem ...
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Convection
Convection is single or multiphase fluid flow that occurs spontaneously due to the combined effects of material property heterogeneity and body forces on a fluid, most commonly density and gravity (see buoyancy). When the cause of the convection is unspecified, convection due to the effects of thermal expansion and buoyancy can be assumed. Convection may also take place in soft solids or mixtures where particles can flow. Convective flow may be transient (such as when a multiphase mixture of oil and water separates) or steady state (see Convection cell). The convection may be due to gravitational, electromagnetic or fictitious body forces. Heat transfer by natural convection plays a role in the structure of Earth's atmosphere, its oceans, and its mantle. Discrete convective cells in the atmosphere can be identified by clouds, with stronger convection resulting in thunderstorms. Natural convection also plays a role in stellar physics. Convection is often categorised or d ...
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Solar And Heliospheric Observatory
The Solar and Heliospheric Observatory (SOHO) is a European Space Agency (ESA) spacecraft built by a European industrial consortium led by Matra Marconi Space (now Airbus Defence and Space) that was launched on a Lockheed Martin Atlas IIAS launch vehicle on 2 December 1995, to study the Sun. It has also discovered over 4,000 comets.(2,703 discoveries as of 21 April 2014)
It began normal operations in May 1996. It is a joint project between the (ESA) and . SOHO was part of the Interna ...
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Phoebus Group
The Phoebus group is an international team of European, Japanese and American scientists aiming at detecting the solar g modes. As of October 5, 2009, the group has finally produced a review summarising the work performed over the past 12 years.The quest for solar g modes, 2009, Astronomy and Astrophysics Review, available at http://adsabs.harvard.edu/abs/2010A%26ARv..18..197A Scientific Rationale Since the beginnings of global helioseismology in the late 1970s, the detection of g modes has been the quest for the Grail. The detection of g modes would be key to the understanding of the internal structure and dynamics of the solar core, as much as the p modes are key to that of the structure of the radiative and convective zones. The impact of g-mode detection would be so large that we could expect a wealth of information to be returned. The structure and dynamics of the energy-generating core will be seen, analyzed and understood. The hydrostatic structure of the core, in particula ...
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Orbiting Solar Observatory
The Orbiting Solar Observatory (abbreviated OSO) Program was the name of a series of American space telescopes primarily intended to study the Sun, though they also included important non-solar experiments. Eight were launched successfully into low Earth orbit by NASA between 1962 and 1975 using Delta rockets. Their primary mission was to observe an 11-year sun spot cycle in UV and X-ray spectra. The initial seven (OSO 1–7) were built by Ball Aerospace, then known as Ball Brothers Research Corporation (BBRC), in Boulder, Colorado.Todd Neff (2010From Jars to the Stars: How Ball Came to Build a Comet-Hunting Machine Denver, CO.: Earthview Media. OSO 8 was built by Hughes Space and Communications Company, in Culver City, California. History The basic design of the entire series featured a rotating section, the "Wheel", to provide gyroscopic stability. A second section, the "Sail", was driven electrically against the Wheel's rotation, and stabilized to point at the Sun. The Sa ...
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Magnetic Cloud
A coronal mass ejection (CME) is a significant release of plasma and accompanying magnetic field from the Sun's corona into the heliosphere. CMEs are often associated with solar flares and other forms of solar activity, but a broadly accepted theoretical understanding of these relationships has not been established. If a CME enters interplanetary space, it is referred to as an interplanetary coronal mass ejection (ICME). ICMEs are capable of reaching and colliding with Earth's magnetosphere, where they can cause geomagnetic storms, aurorae, and in rare cases damage to electrical power grids. The largest recorded geomagnetic perturbation, resulting presumably from a CME, was the solar storm of 1859. Also known as the Carrington Event, it disabled parts of the at the time newly created United States telegraph network, starting fires and shocking some telegraph operators. Near solar maxima, the Sun produces about three CMEs every day, whereas near solar minima, there is abo ...
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Hyder Flare
A Hyder flare is slow, large-scale brightening that occurs in the solar chromosphere.Space Weather Services: Hyder Flares
at the Australian Government Bureau of Meteorology; retrieved February 6, 2016 It resembles a large but feeble and is identifiable as the signature of the sudden disappearance of a

List Of Solar Storms
Solar storms of different types are caused by disturbances on the Sun, most often from coronal mass ejections (CMEs) and solar flares from active regions, or, less often, from coronal holes. Minor to active solar storms (i.e. storming restricted to higher latitudes) may occur under elevated background solar wind conditions when the interplanetary magnetic field (IMF) orientation is southward, toward the Earth (which also leads to much stronger storming conditions from CME-related sources). Background Active stars produce disturbances in space weather and, if strong enough, in their own space climate. Science studies such phenomena with the field of heliophysics, which is an interdisciplinary combination of solar physics and planetary science. In the Solar System, the Sun can produce intense Geomagnetic storm, geomagnetic and Solar particle event, energetic particle storms capable of causing severe damage to technology. It can result in large scale power outages, disruption or Com ...
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List Of Solar Cycles
Solar cycles are nearly periodic 11-year changes in the Sun's activity that are based on the number of sunspots present on the Sun's surface. The first solar cycle conventionally is said to start in 1755 when Rudolf Wolf began extensive reporting of sunspot activity. The source data are the revised International Sunspot Numbers (ISN v2.0), as available at SILSO. Sunspot counts exist since 1610 but the cycle numbering is not well defined during the Maunder minimum. It was proposed that one cycle might have been lost in the late 18th century, but this remains not fully confirmed. Solar cycles can be reconstructed indirectly, using the radiocarbon Carbon-14, C-14, or radiocarbon, is a radioactive isotope of carbon with an atomic nucleus containing 6 protons and 8 neutrons. Its presence in organic materials is the basis of the radiocarbon dating method pioneered by Willard Libby and coll ... 14C proxy, for the last millennium. The smoothing is done using the traditional SIDC smo ...
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Black Body Radiation
Black-body radiation is the thermal electromagnetic radiation within, or surrounding, a body in thermodynamic equilibrium with its environment, emitted by a black body (an idealized opaque, non-reflective body). It has a specific, continuous spectrum of wavelengths, inversely related to intensity, that depend only on the body's temperature, which is assumed, for the sake of calculations and theory, to be uniform and constant., Chapter 13. A perfectly insulated enclosure which is in thermal equilibrium internally contains black-body radiation, and will emit it through a hole made in its wall, provided the hole is small enough to have a negligible effect upon the equilibrium. The thermal radiation spontaneously emitted by many ordinary objects can be approximated as black-body radiation. Of particular importance, although planets and stars (including the Earth and Sun) are neither in thermal equilibrium with their surroundings nor perfect black bodies, black-body radiation is s ...
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Growing Sunspots Tracking Closeup - February 2011
Growing may refer to: * Growth (other) * Growing (band), a noise band based in Brooklyn, New York * ''Growing'' (Sleeping People album), 2007 *Growing (Rina Chinen album) * Growing, a children's song sung on the television program Barney & Friends * ''Growing'', an autobiographical book by Leonard Woolf See also * * * Grow (other) Grow or GROW may refer to: * Growth (other), an increase in some quantity over time or a measure of some principal * GROW model, a technique for problem solving or goal setting * Graphical ROMable Object Windows, a windowing system that ...

Magnetic Field
A magnetic field is a vector field that describes the magnetic influence on moving electric charges, electric currents, and magnetic materials. A moving charge in a magnetic field experiences a force perpendicular to its own velocity and to the magnetic field. A permanent magnet's magnetic field pulls on ferromagnetic materials such as iron, and attracts or repels other magnets. In addition, a nonuniform magnetic field exerts minuscule forces on "nonmagnetic" materials by three other magnetic effects: paramagnetism, diamagnetism, and antiferromagnetism, although these forces are usually so small they can only be detected by laboratory equipment. Magnetic fields surround magnetized materials, and are created by electric currents such as those used in electromagnets, and by electric fields varying in time. Since both strength and direction of a magnetic field may vary with location, it is described mathematically by a function assigning a vector to each point of space, cal ...
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