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Soft Gamma Repeaters
A soft gamma repeater (SGR) is an astronomical object which emits large bursts of gamma-rays and X-rays at irregular intervals. It is conjectured that they are a type of magnetar or, alternatively, neutron stars with fossil disks around them. History On March 5, 1979 a powerful gamma-ray burst was noted. As a number of receivers at different locations in the Solar System saw the burst at slightly different times, its direction could be determined, and it was shown to originate from near a supernova remnant in the Large Magellanic Cloud. Over time it became clear that this was not a normal gamma-ray burst. The photons were less energetic in the soft gamma-ray and hard X-ray range, and repeated bursts came from the same region. Astronomer Chryssa Kouveliotou of the Universities Space Research Association (USRA) at NASA's Marshall Space Flight Center decided to test the theory that soft gamma repeaters were magnetars. According to the theory, the bursts would cause the object to ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Astronomy
Astronomy () is a natural science that studies celestial objects and phenomena. It uses mathematics, physics, and chemistry in order to explain their origin and evolution. Objects of interest include planets, moons, stars, nebulae, 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 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 Babylonians, Greeks, Indians, Egyptians, Chinese, Maya, and many ancient indigenous peoples of the Americas. In the past, astronomy included disciplines as diverse as astrometry, celestial navigation, observational astronomy, and the making of calendars. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Gauss (unit)
The gauss, symbol (sometimes Gs), is a unit of measurement of magnetic induction, also known as '' magnetic flux density''. The unit is part of the Gaussian system of units, which inherited it from the older CGS-EMU system. It was named after the German mathematician and physicist Carl Friedrich Gauss in 1936. One gauss is defined as one maxwell per square centimetre. As the cgs system has been superseded by the International System of Units (SI), the use of the gauss has been deprecated by the standards bodies, but is still regularly used in various subfields of science. The SI unit for magnetic flux density is the tesla (symbol T), which corresponds to . Name, symbol, and metric prefixes Albeit not a component of the International System of Units, the usage of the gauss generally follows the rules for SI units. Since the name is derived from a person's name, its symbol is the uppercase letter ''G''. When the unit is spelled out, it is written in lowercase ("gauss"), unless ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
European Space Agency
, owners = , headquarters = Paris, Île-de-France, France , coordinates = , spaceport = Guiana Space Centre , seal = File:ESA emblem seal.png , seal_size = 130px , image = Views in the Main Control Room (12052189474).jpg , size = , caption = , acronym = , established = , employees = 2,200 , administrator = Director General Josef Aschbacher , budget = €7.2 billion (2022) , language = English and French (working languages) , website = , logo = European Space Agency logo.svg , logo_caption = Logo , image_caption = European Space Operations Centre (ESOC) Main Control Room The European Space Agency (ESA; french: Agence spatiale européenne , it, Agenzia Spaziale Europea, es, Agencia Espacial Europea ASE; german: Europäische Weltraumorganisation) is an intergovernmental organisation of 22 member states dedicated to the exploration of space. Established in 1975 and headquartere ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
SGR 0501+4516
SGR 0501+4516 is a magnetar that is a soft gamma repeater (SGR). Currently, the phenomenons of SGRs and the related Anomalous X-ray pulsars (AXP) are explained as arising from magnetars. SGR 0501+4516 is located approximately 15,000 light years from Earth and has a magnetic field 100 trillion times stronger than the Earth's. SGR 0501+4516 is remarkable in that it has been the first SGR to have been discovered after ten years without SGR detections. N. Rea, G. L. Israel, R. Turoll et al., ''The first outburst of the new magnetar candidate SGR 0501+4516'', Monthly Notices of the Royal Astronomical Society, Volume 396, Issue 4, pages 2419–2432, July 2009, , It has been suggested that SGR 0501+4516, together with 1E 1547.0-5408, should be considered as tools for a final unification of SGRs, AXPs and the “transient AXPs (TAXPs)” into a single class of “magnetars candidates”. Discovery Its existence was reported on Aug. 22, 2008, by NASA's Swift satellite, which repor ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Space
Space is the boundless three-dimensional extent in which objects and events have relative position and direction. In classical physics, physical space is often conceived in three linear dimensions, although modern physicists usually consider it, with time, to be part of a boundless four-dimensional continuum known as spacetime. The concept of space is considered to be of fundamental importance to an understanding of the physical universe. However, disagreement continues between philosophers over whether it is itself an entity, a relationship between entities, or part of a conceptual framework. Debates concerning the nature, essence and the mode of existence of space date back to antiquity; namely, to treatises like the ''Timaeus'' of Plato, or Socrates in his reflections on what the Greeks called '' khôra'' (i.e. "space"), or in the ''Physics'' of Aristotle (Book IV, Delta) in the definition of ''topos'' (i.e. place), or in the later "geometrical conception of place" ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
SGR J1550−5418
SGR J1550−5418 is a soft gamma repeater (SGR), the sixth to be discovered, located in the constellation Norma. Long known as an X-ray source, it was noticed to have become active on 23 October 2008, and then after a relatively quiescent interval, became much more active on 22 January 2009. It has been observed by the Swift satellite, and by the Fermi Gamma-ray Space Telescope, launched in 2008, as well as in X-ray and radio emission. It has been observed to emit intense bursts of gamma rays at a rate of up to several per minute. At its estimated distance of 30,000 light years (~10 kpc), the most intense flares equal the total energy emission of the Sun in ~20 years. The underlying object is believed to be a rotating neutron star, of the type known as ''magnetars'', which have magnetic fields up to 1015 gauss, about 1000 times that of more typical neutron star X-ray sources. See orders of magnitude (magnetic field) for examples of other magnetic field strengths. The rotation per ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
SGR 1627−41
SGR 1627−41, is a soft gamma repeater (SGR), located in the constellation of Ara. It was discovered June 15, 1998 using the Burst and transient Source Experiment ( BATSE) and was the first soft gamma repeater to be discovered since 1979. During a period of 6 weeks, the star bursted approximately 100 times, and then went quiet. The measured bursts lasted an average of 100 milliseconds, but ranged from 25 ms to 1.8 seconds. SGR 1627−41 is a persistent X-ray source. It is located at a distance of 11 kpc in the radio complex CTB 33, a star forming region that includes the supernova remnant G337.0-0.1. This object is believed to be a neutron star that undergoes random outbursts of hard and soft X-rays. This may be caused by the loss of angular momentum of a highly magnetized neutron star, or magnetar. Alternatively, it may be a quark star A quark star is a hypothetical type of compact, exotic star, where extremely high core temperature and pressure has forced nucle ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Earth's Atmosphere
The atmosphere of Earth is the layer of gases, known collectively as air, retained by Earth's gravity that surrounds the planet and forms its planetary atmosphere. The atmosphere of Earth protects life on Earth by creating pressure allowing for liquid water to exist on the Earth's surface, absorbing ultraviolet solar radiation, warming the surface through heat retention ( greenhouse effect), and reducing temperature extremes between day and night (the diurnal temperature variation). By mole fraction (i.e., by number of molecules), dry air contains 78.08% nitrogen, 20.95% oxygen, 0.93% argon, 0.04% carbon dioxide, and small amounts of other gases. Air also contains a variable amount of water vapor, on average around 1% at sea level, and 0.4% over the entire atmosphere. Air composition, temperature, and atmospheric pressure vary with altitude. Within the atmosphere, air suitable for use in photosynthesis by terrestrial plants and breathing of terrestrial animals is fo ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
SGR 1806−20
SGR 1806−20 is a magnetar, a type of neutron star with a very powerful magnetic field, that was discovered in 1979 and identified as a soft gamma repeater. SGR 1806−20 is located about 13 kiloparsecs (42,000 light-years) from Earth on the far side of the Milky Way in the constellation of Sagittarius. It has a diameter of no more than and rotates on its axis every 7.5 seconds ( rotation speed at the surface). , SGR 1806-20 is the most highly magnetized object ever observed, with a magnetic field over 1015 gauss (G) (1011 tesla) in intensity (compared to the Sun's 1–5 G and Earth's 0.25–0.65 G). Explosion Fifty thousand years after a starquake occurred on the surface of SGR 1806-20, the radiation from the resultant explosion reached Earth on December 27, 2004 ( GRB 041227). In terms of gamma rays, the burst had an absolute magnitude around −29. It was the brightest event known to have been sighted on this planet from an origin outside the Solar System, unti ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
SGR 0525−66
SGR may refer to: * Heart Colchester and Heart Ipswich, radio stations in Suffolk, England both once known as SGR * Sagittarius (constellation) abbreviation * ''Scary Go Round'', a webcomic * Scientists for Global Responsibility, a United Kingdom group that promotes the ethical practice and use of science and technology * Segar LRT station in Bukit Panjang, Singapore (LRT station abbreviation) * Select Graphic Rendition (ANSI), an ANSI X3.64 escape sequence * Service Général du Renseignement et de la Sécurité, the French name of the Belgian General Information and Security Service * SGR (band), a ska band from New Jersey, United States * Shale Gouge Ratio, a mathematical algorithm aiming to predict the fault rock types for simple fault zones * The Shaw Group, a company which formerly used as its ticker symbol * Slade Green railway station in London, England (National Rail station code) * Smart Green Resilient (planning concept) abbreviation * Societa' di Gestione del Risp ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Satellite
A satellite or artificial satellite is an object intentionally placed into orbit in outer space. Except for passive satellites, most satellites have an electricity generation system for equipment on board, such as solar panels or radioisotope thermoelectric generators (RTGs). Most satellites also have a method of communication to ground stations, called transponders. Many satellites use a standardized bus to save cost and work, the most popular of which is small CubeSats. Similar satellites can work together as a group, forming constellations. Because of the high launch cost to space, satellites are designed to be as lightweight and robust as possible. Most communication satellites are radio relay stations in orbit and carry dozens of transponders, each with a bandwidth of tens of megahertz. Satellites are placed from the surface to orbit by launch vehicles, high enough to avoid orbital decay by the atmosphere. Satellites can then change or maintain the orbit by p ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
