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Coronal Radiative Losses
In astronomy and in astrophysics, for radiative losses of the solar corona, it is meant the energy flux radiated from the external atmosphere of the Sun (traditionally divided into chromosphere, transition region and corona), and, in particular, the processes of production of the radiation coming from the solar corona and transition region, where the plasma is optically-thin. On the contrary, in the chromosphere, where the temperature decreases from the photospheric value of 6000 K to the minimum of 4400 K, the optical depth is about 1, and the radiation is thermal. The corona extends much further than a solar radius from the photosphere and looks very complex and inhomogeneous in the X-rays images taken by satellites (see the figure on the right taken by the XRT on board Hinode). The structure and dynamics of the corona are dominated by the solar magnetic field. There are strong evidences that even the heating mechanism, responsible for its high temperature of million deg ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Astronomy
Astronomy () is a natural science that studies astronomical object, celestial objects and phenomena. It uses mathematics, physics, and chemistry in order to explain their origin and chronology of the Universe, evolution. Objects of interest include planets, natural satellite, moons, stars, nebulae, galaxy, galaxies, and comets. Relevant phenomena include supernova explosions, gamma ray bursts, quasars, blazars, pulsars, and cosmic microwave background radiation. More generally, astronomy studies everything that originates beyond atmosphere of Earth, Earth's atmosphere. Cosmology is a branch of astronomy that studies the universe as a whole. Astronomy is one of the oldest natural sciences. The early civilizations in recorded history made methodical observations of the night sky. These include the Babylonian astronomy, Babylonians, Greek astronomy, Greeks, Indian astronomy, Indians, Egyptian astronomy, Egyptians, Chinese astronomy, Chinese, Maya civilization, Maya, and many anc ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Galactic Halo
A galactic halo is an extended, roughly spherical component of a galaxy which extends beyond the main, visible component. Several distinct components of galaxies comprise the halo: * the stellar halo * the galactic corona (hot gas, i.e. a plasma) * the dark matter halo The distinction between the halo and the main body of the galaxy is clearest in spiral galaxies, where the spherical shape of the halo contrasts with the flat disc. In an elliptical galaxy, there is no sharp transition between the other components of the galaxy and the halo. A halo can be studied by observing its effect on the passage of light from distant bright objects like quasars that are in line of sight beyond the galaxy in question. Components of the galactic halo Stellar halo The stellar halo is a nearly spherical population of field stars and globular clusters. It surrounds most disk galaxies as well as some elliptical galaxies of type cD. A low amount (about one percent) of a galaxy's stellar mas ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Astronomical X-ray Source
Astrophysical X-ray sources are astronomical objects with physical properties which result in the emission of X-rays. Several types of astrophysical objects emit X-rays. They include galaxy clusters, black holes in active galactic nuclei (AGN), galactic objects such as supernova remnants, stars, and binary stars containing a white dwarf (cataclysmic variable stars and super soft X-ray sources), neutron star or black hole (X-ray binaries). Some Solar System bodies emit X-rays, the most notable being the Moon, although most of the X-ray brightness of the Moon arises from reflected solar X-rays. Furthermore, celestial entities in space are discussed as celestial X-ray sources. The origin of all observed astronomical X-ray sources is in, near to, or associated with a coronal cloud or gas at coronal cloud temperatures for however long or brief a period. A combination of many unresolved X-ray sources is thought to produce the observed X-ray background. The X-ray continuum can arise f ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Plasma (physics)
Plasma () 1, where \nu_ is the electron gyrofrequency and \nu_ is the electron collision rate. It is often the case that the electrons are magnetized while the ions are not. Magnetized plasmas are ''anisotropic'', meaning that their properties in the direction parallel to the magnetic field are different from those perpendicular to it. While electric fields in plasmas are usually small due to the plasma high conductivity, the electric field associated with a plasma moving with velocity \mathbf in the magnetic field \mathbf is given by the usual Lorentz force, Lorentz formula \mathbf = -\mathbf\times\mathbf, and is not affected by Debye shielding. Mathematical descriptions To completely describe the state of a plasma, all of the particle locations and velocities that describe the electromagnetic field in the plasma region would need to be written down. However, it is generally not practical or necessary to keep track of all the particles in a plasma. Therefore, plasma physicist ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Photons
A photon () is an elementary particle that is a quantum of the electromagnetic field, including electromagnetic radiation such as light and radio waves, and the force carrier for the electromagnetic force. Photons are massless, so they always move at the speed of light in vacuum, (or about ). The photon belongs to the class of bosons. As with other elementary particles, photons are best explained by quantum mechanics and exhibit wave–particle duality, their behavior featuring properties of both waves and particles. The modern photon concept originated during the first two decades of the 20th century with the work of Albert Einstein, who built upon the research of Max Planck. While trying to explain how matter and electromagnetic radiation could be in thermal equilibrium with one another, Planck proposed that the energy stored within a material object should be regarded as composed of an integer number of discrete, equal-sized parts. To explain the photoelectric effect, Ein ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
TRACE
Trace may refer to: Arts and entertainment Music * Trace (Son Volt album), ''Trace'' (Son Volt album), 1995 * Trace (Died Pretty album), ''Trace'' (Died Pretty album), 1993 * Trace (band), a Dutch progressive rock band * The Trace (album), ''The Trace'' (album) Other uses in arts and entertainment * Trace (magazine), ''Trace'' (magazine), British hip-hop magazine * Trace (manhwa), ''Trace'' (manhwa), a Korean internet cartoon * Trace (novel), ''Trace'' (novel), a novel by Patricia Cornwell * The Trace (film), ''The Trace'' (film), a 1994 Turkish film * The Trace (video game), ''The Trace'' (video game), 2015 video game * Sama (film), ''Sama'' (film), alternate title ''The Trace'', a 1988 Tunisian film * Trace, a fictional character in the game ''Metroid Prime Hunters'' * Trace, the protagonist of ''Axiom Verge'' * Trace, another name for List of One Piece characters#Portgas D. Ace, Portgas D. Ace, a fictional character in the manga ''One Piece'' * TRACE, the main brand for a numb ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Yohkoh
Yohkoh (, ''Sunbeam'' in Japanese), known before launch as Solar-A, was a Solar observatory spacecraft of the Institute of Space and Astronautical Science (Japan), in collaboration with space agencies in the United States and the United Kingdom. It was launched into Earth orbit on August 30, 1991 by the M-3SII rocket from Kagoshima Space Center. It took its first soft X-ray image on September 13, 1991, 21:53:40, and movie representations of the X-ray corona over 1991-2001 are available at thYohkoh Legacy site Description The satellite was three-axis stabilized and in a near-circular orbit. It carried four instruments: a Soft X-ray Telescope (SXT), a Hard X-ray Telescope (HXT), a Bragg Crystal Spectrometer (BCS), and a Wide Band Spectrometer (WBS). About 50 MB were generated each day and stored on board by a 10.5 MB bubble memory recorder. Because SXT utilized a charge-coupled device (CCD) as its readout device, perhaps being the first X-ray astronomical telescope to do ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
NIXT
The NIXT, or Normal Incidence X-ray Telescope, was a sounding rocket payload flown in the 1990s by Professor Leon Golub of the Smithsonian Astrophysical Observatory, to prototype normal-incidence (conventional) optical designs in extreme ultraviolet (EUV) solar imaging. In the EUV, the surface of the Sun appears dark, and hot structures in the solar corona appear bright; this allows study of the structure and dynamics of the solar corona near the surface of the Sun, which is not possible using visible light. NIXT and its sister rocket, the MSSTA, were the prototypes for all normal-incidence EUV imaging instruments in use today, including SOHO/EIT, TRACE, and STEREO/SECCHI. In 1989, a NIXT sounding rocket launch detected soft X-Rays coming from a Solar flare. It was launched when the solar event was detected to allow high resolution imaging of the Sun's corona Corona (from the Latin for 'crown') most commonly refers to: * Stellar corona, the outer atmosphere of the Sun ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Solar Maximum Mission
The Solar Maximum Mission satellite (or SolarMax) was designed to investigate Sun, Solar phenomena, particularly solar flares. It was launched on February 14, 1980. The SMM was the first satellite based on the Multimission Modular Spacecraft bus manufactured by Fairchild Industries, a platform which was later used for Landsat 4, Landsats 4 and Landsat 5, 5 as well as the Upper Atmosphere Research Satellite. After an attitude control failure in Nov 1980 it was put in standby mode until April 1984 when it was repaired by a Shuttle mission. The Solar Maximum Mission ended on December 2, 1989, when the spacecraft Atmospheric reentry, re-entered the atmosphere and burned up over the Indian Ocean. Instruments Failure and repair The white-light coronagraph/polarimeter (C/P) took coronal images for about six months from March 1980 before suffering an electronics failure in September that prevented operation. In November 1980, the second of four fuses in SMM's attitude control system ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
