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Heliophysics Science Division
The ''Heliophysics Science Division'' of the Goddard Space Flight Center (NASA) conducts research on the Sun, its extended Solar System environment (the heliosphere), and interactions of Earth, other planets, small bodies, and interstellar gas with the heliosphere. Division research also encompasses geospace—Earth's uppermost atmosphere, the ionosphere, and the magnetosphere—and the changing environmental conditions throughout the coupled heliosphere (solar system weather). Scientists in the ''Heliophysics Science Division'' develop models, spacecraft missions and instruments, and systems to manage and disseminate heliophysical data. They interpret and evaluate data gathered from instruments, draw comparisons with computer simulations and theoretical models, and publish the results. The Division also conducts education and public outreach programs to communicate the excitement and social value of NASA heliophysics. Laboratories Goddard's Heliophysics Science Division cons ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Science Of IRIS Mission
Science is a systematic endeavor that builds and organizes knowledge in the form of testable explanations and predictions about the universe. Science may be as old as the human species, and some of the earliest archeological evidence for scientific reasoning is tens of thousands of years old. The earliest written records in the history of science come from Ancient Egypt and Mesopotamia in around 3000 to 1200 BCE. Their contributions to mathematics, astronomy, and medicine entered and shaped Greek natural philosophy of classical antiquity, whereby formal attempts were made to provide explanations of events in the physical world based on natural causes. After the fall of the Western Roman Empire, knowledge of Greek conceptions of the world deteriorated in Western Europe during the early centuries (400 to 1000 CE) of the Middle Ages, but was preserved in the Muslim world during the Islamic Golden Age and later by the efforts of Byzantine Greek scholars who brought Greek ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
THEMIS
In Greek mythology and religion, Themis (; grc, Θέμις, Themis, justice, law, custom) is one of the twelve Titan children of Gaia and Uranus, and the second wife of Zeus. She is the goddess and personification of justice, divine order, fairness, law, and custom, and her symbols include the Scales of Justice. She is also associated with oracles and prophecies, including the Oracle of Delphi. Name ''Themis'' means "divine law" rather than human ordinance, literally "that which is put in place", from the Greek verb ''títhēmi'' ( τίθημι), meaning "to put." To the ancient Greeks she was originally the organizer of the "communal affairs of humans, particularly assemblies." Moses Finley remarked of ''themis'', as the word was used by Homer in the 8th century BCE, to evoke the social order of the 10th- and 9th-century Greek Dark Ages: Finley adds, "There was ''themis''—custom, tradition, folk-ways, ''mores'', whatever we may call it, the enormous power of 'it is ( ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Solar Transition Region
The solar transition region is a region of the Sun's atmosphere between the upper chromosphere and corona. It is important because it is the site of several unrelated but important transitions in the physics of the solar atmosphere: * Below, gravity tends to dominate the shape of most features, so that the Sun may often be described in terms of layers and horizontal features (like sunspots); above, dynamic forces dominate the shape of most features, so that the transition region itself is not a well-defined layer at a particular altitude. * Below, most of the helium is not fully ionized, so that it radiates energy very effectively; above, it becomes fully ionized. This has a profound effect on the equilibrium temperature (see below). * Below, the material is opaque to the particular colors associated with spectral lines, so that most spectral lines formed below the transition region are absorption lines in infrared, visible light, and near ultraviolet, while most lines formed at ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Rutherford Backscattering Spectrometry
Rutherford backscattering spectrometry (RBS) is an analytical technique used in materials science. Sometimes referred to as high-energy ion scattering (HEIS) spectrometry, RBS is used to determine the structure and composition of materials by measuring the backscattering of a beam of high energy ions (typically protons or alpha particles) impinging on a sample. Geiger–Marsden experiment Rutherford backscattering spectrometry is named after Lord Rutherford, a physicist sometimes referred to as the father of nuclear physics. Rutherford supervised a series of experiments carried out by Hans Geiger and Ernest Marsden between 1909 and 1914 studying the scattering of alpha particles through metal foils. While attempting to eliminate "stray particles" they believed to be caused by an imperfection in their alpha source, Rutherford suggested that Marsden attempt to measure backscattering from a gold foil sample. According to the then-dominant plum-pudding model of the atom, in ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Solar Transition Region
The solar transition region is a region of the Sun's atmosphere between the upper chromosphere and corona. It is important because it is the site of several unrelated but important transitions in the physics of the solar atmosphere: * Below, gravity tends to dominate the shape of most features, so that the Sun may often be described in terms of layers and horizontal features (like sunspots); above, dynamic forces dominate the shape of most features, so that the transition region itself is not a well-defined layer at a particular altitude. * Below, most of the helium is not fully ionized, so that it radiates energy very effectively; above, it becomes fully ionized. This has a profound effect on the equilibrium temperature (see below). * Below, the material is opaque to the particular colors associated with spectral lines, so that most spectral lines formed below the transition region are absorption lines in infrared, visible light, and near ultraviolet, while most lines formed at ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Chromosphere
A chromosphere ("sphere of color") is the second layer of a star's atmosphere, located above the photosphere and below the solar transition region and corona. The term usually refers to the Sun's chromosphere, but not exclusively. In the Sun's atmosphere, the chromosphere is roughly in height, or slightly more than 1% of the Sun's radius at maximum thickness. It possesses a homogeneous layer at the boundary with the photosphere. Hair-like jets of plasma, called spicules, rise from this homogeneous region and through the chromosphere, extending up to into the corona above. The chromosphere has a characteristic red color due to electromagnetic emissions in the ''H''α spectral line. Information about the chromosphere is primarily obtained by analysis of its emitted electromagnetic radiation. Chromospheres have also been observed on stars other than the Sun. On large stars, chromospheres sometimes make up a significant proportion of the entire star. For example, the chr ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Plasma (physics)
Plasma ()πλάσμα , Henry George Liddell, Robert Scott, ''A Greek English Lexicon'', on Perseus is one of the four fundamental states of matter. It contains a significant portion of charged particles – ions and/or s. The presence of these charged particles is what primarily sets plasma apart from the other fundamental states of matter. It is the most abundant form of [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Solar Corona
A corona ( coronas or coronae) is the outermost layer of a star's atmosphere. It consists of plasma. The Sun's corona lies above the chromosphere and extends millions of kilometres into outer space. It is most easily seen during a total solar eclipse, but it is also observable with a coronagraph. Spectroscopic measurements indicate strong ionization in the corona and a plasma temperature in excess of , much hotter than the surface of the Sun, known as the photosphere. The word ''corona'' is , in turn derived . History In 1724, French-Italian astronomer Giacomo F. Maraldi recognized that the aura visible during a solar eclipse belongs to the Sun, not to the Moon. In 1809, Spanish astronomer José Joaquín de Ferrer coined the term 'corona'. Based in his own observations of the 1806 solar eclipse at Kinderhook (New York), de Ferrer also proposed that the corona was part of the Sun and not of the Moon. English astronomer Norman Lockyer identified the first element unknow ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Photosphere
The photosphere is a star's outer shell from which light is radiated. The term itself is derived from Ancient Greek roots, φῶς, φωτός/''phos, photos'' meaning "light" and σφαῖρα/''sphaira'' meaning "sphere", in reference to it being a spherical surface that is perceived to emit light. It extends into a star's surface until the plasma becomes opaque, equivalent to an optical depth of approximately , or equivalently, a depth from which 50% of light will escape without being scattered. A photosphere is the deepest region of a luminous object, usually a star, that is transparent to photons of certain wavelengths. Temperature The surface of a star is defined to have a temperature given by the effective temperature in the Stefan–Boltzmann law. Stars, except neutron stars, have no solid or liquid surface. Therefore, the photosphere is typically used to describe the Sun's or another star's visual surface. Composition of the Sun The Sun is composed primari ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Interface Region Imaging Spectrograph
Interface Region Imaging Spectrograph (IRIS), also called Explorer 94 and SMEX-12, is a NASA solar observation satellite. The mission was funded through the Small Explorer program to investigate the physical conditions of the solar limb, particularly the interface region made up of the chromosphere and transition region. The spacecraft consists of a satellite bus and spectrometer built by the Lockheed Martin Solar and Astrophysics Laboratory (LMSAL), and a telescope provided by the Smithsonian Astrophysical Observatory (SAO). IRIS is operated by LMSAL and NASA's Ames Research Center. The satellite's instrument is a high-frame-rate ultraviolet imaging spectrometer, providing one image per second at 0.3 arcsecond angular resolution and sub-ångström spectral resolution. NASA announced, on 19 June 2009, that IRIS was selected from six Small Explorer mission candidates for further study, along with the Gravity and Extreme Magnetism (GEMS) space observatory. Mission IRIS i ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Geotail
Geotail was a satellite that observed the Earth's magnetosphere. It was developed by Japan's ISAS in association with the United States' NASA, and was launched by a Delta II rocket on 24 July 1992 from Cape Canaveral Air Force Station. The primary purpose of this mission is to study the structure and dynamics of the tail region of the magnetosphere with a comprehensive set of scientific instruments. For this purpose, the orbit has been designed to cover the magnetotail over a wide range of distances: to from the earth. This orbit also allowed it to study the boundary region of the magnetosphere as it skims the magnetopause at perigees. In the first two years the double lunar swing-by technique was used to keep apogees in the distant magnetotail. This involved 14 lunar flybys. In 1993 the computer that controls the Low Energy Particles experiment locked up. Attempts to reset it failed. This problem was solved by changing the trajectory of the craft during a lunar flyby that too ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cluster II (spacecraft)
Cluster II is a space mission of the European Space Agency, with NASA participation, to study the Earth's magnetosphere over the course of nearly two solar cycles. The mission is composed of four identical spacecraft flying in a tetrahedral formation. As a replacement for the original Cluster spacecraft which were lost in a launch failure in 1996, the four Cluster II spacecraft were successfully launched in pairs in July and August 2000 onboard two Soyuz-Fregat rockets from Baikonur, Kazakhstan. In February 2011, Cluster II celebrated 10 years of successful scientific operations in space. , its mission has been extended until the end of 2022. China National Space Administration/ESA Double Star mission operated alongside Cluster II from 2004 to 2007. Mission overview The four identical Cluster II satellites study the impact of the Sun's activity on the Earth's space environment by flying in formation around Earth. For the first time in space history, this mission is able to ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
