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Anders Jonas Ångström
Anders Jonas Ångström (; 13 August 181421 June 1874) was a Swedish physicist and one of the founders of the science of spectroscopy.P.Murdin (2000): "Angstrom" chapter in ''Encyclopedia of Astronomy and Astrophysics''. Ångström is also well known for his studies of astrophysics, heat transfer, terrestrial magnetism, and the aurora borealis. In 1852, Ångström formulated in ''Optiska undersökningar'' (Optical investigations), a law of absorption, later modified somewhat and known as Kirchhoff's law of thermal radiation. Biography Anders Jonas Ångström was born in Medelpad to Johan Ångström, and schooled in Härnösand. He moved to Uppsala in 1833 and was educated at Uppsala University, where in 1839 he became docent in physics. In 1842 he went to the Stockholm Observatory to gain experience in practical astronomical work, and the following year he was appointed keeper of the Uppsala Astronomical Observatory. Intrigued by terrestrial magnetism he recorded observati ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Timrå Municipality
Timrå Municipality (''Timrå kommun'') is a municipality in Västernorrland County, Sweden. The town of Timrå is the municipal seat. The rural municipality ''Timrå'' was made a market town (''köping'') in 1947. The present municipality was created in 1971 when Timrå was amalgamated with ''Hässjö''. Geography Timrå is located in a terrain of forest and hills. Traditionally the industry has been dominated by forestry. The timber was transported through the rivers and streams to their destination, most often to sawmills. In tribute to this, the city arms depicts trees and water. Localities * Bergeforsen * Stavreviken * Söråker * Sörberge * Timrå (seat) Notable citizens *Lennart Svedberg Jan Lennart "Lill-Strimma" Svedberg (29 February 1944 – 29 July 1972) was a Swedish ice hockey defenceman. He played for Timrå IK and Brynäs IF. He also played on the Swedish national team during six IIHF World Championships and t ... (1944-1972), ice hockey p ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Earth's Magnetic Field
Earth's magnetic field, also known as the geomagnetic field, is the magnetic field that extends from Earth's interior out into space, where it interacts with the solar wind, a stream of charged particles emanating from the Sun. The magnetic field is generated by electric currents due to the motion of convection currents of a mixture of molten iron and nickel in Earth's outer core: these convection currents are caused by heat escaping from the core, a natural process called a geodynamo. The magnitude of Earth's magnetic field at its surface ranges from . As an approximation, it is represented by a field of a magnetic dipole currently tilted at an angle of about 11° with respect to Earth's rotational axis, as if there were an enormous bar magnet placed at that angle through the center of Earth. The North geomagnetic pole actually represents the South pole of Earth's magnetic field, and conversely the South geomagnetic pole corresponds to the north pole of Earth's magneti ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Heat
In thermodynamics, heat is defined as the form of energy crossing the boundary of a thermodynamic system by virtue of a temperature difference across the boundary. A thermodynamic system does not ''contain'' heat. Nevertheless, the term is also often used to refer to the thermal energy contained in a system as a component of its internal energy and that is reflected in the temperature of the system. For both uses of the term, heat is a form of energy. An example of formal vs. informal usage may be obtained from the right-hand photo, in which the metal bar is "conducting heat" from its hot end to its cold end, but if the metal bar is considered a thermodynamic system, then the energy flowing within the metal bar is called internal energy, not heat. The hot metal bar is also transferring heat to its surroundings, a correct statement for both the strict and loose meanings of ''heat''. Another example of informal usage is the term '' heat content'', used despite the fact that ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Terrestrial Magnetism
Earth's magnetic field, also known as the geomagnetic field, is the magnetic field that extends from Earth's interior out into space, where it interacts with the solar wind, a stream of charged particles emanating from the Sun. The magnetic field is generated by electric currents due to the motion of convection currents of a mixture of molten iron and nickel in Earth's outer core: these convection currents are caused by heat escaping from the core, a natural process called a geodynamo. The magnitude of Earth's magnetic field at its surface ranges from . As an approximation, it is represented by a field of a magnetic dipole currently tilted at an angle of about 11° with respect to Earth's rotational axis, as if there were an enormous bar magnet placed at that angle through the center of Earth. The North geomagnetic pole actually represents the South pole of Earth's magnetic field, and conversely the South geomagnetic pole corresponds to the north pole of Earth's magnetic fiel ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Uppsala Astronomical Observatory
The Uppsala Astronomical Observatory (UAO), Astronomiska observatoriet i Uppsala) is the oldest astronomical observatory in Sweden. It was founded in 1741, though there was a professorial chair of astronomy at the University of Uppsala from 1593 and the university archives include lecture notes in astronomy from the 1480s. In the 18th century, Anders Celsius performed his research there and built the first observatory proper in 1741. Celsius got the university consistory to buy a large stone house of medieval origin in central Uppsala, where he had an observatory constructed on the rooftop. Celsius both worked and had his personal living quarters in the house. This observatory remained in use until the new observatory, now known as the "old observatory", was built in 1853. The Celsius house itself remains as one of few older buildings on a modern shopping street, but the observatory on the roof was demolished in 1857. In the 19th century Anders Jonas Ångström was keeper of t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Stockholm Observatory
The Stockholm Observatory ( sv, Stockholms observatorium, 050) is an astronomical observatory and institution in Stockholm, Sweden, founded in the 18th century and today part of Stockholm University. In 1931, the new Stockholm Observatory ( sv, Saltsjöbaden Observatory, 052), nicknamed "Saltis", was inaugurated on the Karlsbaderberget at Saltsjöbaden, near Stockholm, and operated until 2001. There are records of daily weather observations from the observatory going back to 1754. The Stockholm Observatory site at Saltsjöbaden was established with a 40-inch (102 cm) reflecting telescope from Grubb, built in 1931. Also of historical interest is a double telescope by Grubb, the 24/20-inch refractor, with has one 24-inch aperture another 20-inch on the same mount established in 1931. The old observatory is in modern times a museum (Observatory Museum) and because it is on a hill is known for a good view of city of Stockholm from the dome, and it also has some sculptures and ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Docent
The title of docent is conferred by some European universities to denote a specific academic appointment within a set structure of academic ranks at or below the full professor rank, similar to a British readership, a French " ''maître de conférences''" (MCF), and equal to or above the title of " associate professor". Docent is also used at some (mainly German) universities generically for a person who has the right to teach. The term is derived from the Latin word ''docēns'', which is the present active participle of ''docēre'' (to teach, to lecture). Becoming a docent is often referred to as Habilitation or doctor of science and is an academic qualification that shows that the holder is qualified to be employed at the level of associate or full professor. Docent is the highest academic title in several countries, and the qualifying criteria are research output that corresponds to 3-5 doctoral dissertations, supervision of PhD students, and experience in teaching at the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Härnösand
Härnösand () is a locality and the seat of Härnösand Municipality in Västernorrland County, Sweden with 17,556 inhabitants in 2010. It is called "the gate to the High Coast" because of the world heritage landscape just a few miles north of Härnösand. Härnösand is the seat of the Diocese of Härnösand. History On 10 December 1885, Härnösand became the first town in Sweden with electric street lighting, following the Gådeå power station being taken into use. Education Härnösand is the seat of The National Agency for Special Needs Education and Schools (''Specialpedagogiska skolmyndigheten''). The Swedish International Development Cooperation Agency (Sida) operates its training programme Sida Partnership Forum in Härnösand. Industry One of the biggest employers in Härnösand is the cable-TV and Cable internet service provider Com Hem. Sports The women's team of the bandy club Härnösands AIK plays in the highest division and the men's team ha ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Kirchhoff's Law Of Thermal Radiation
In heat transfer, Kirchhoff's law of thermal radiation refers to wavelength-specific radiative emission and absorption by a material body in thermodynamic equilibrium, including radiative exchange equilibrium. It is a special case of Onsager reciprocal relations as a consequence of the time reversibility of microscopic dynamics, also known as microscopic reversibility. A body at temperature radiates electromagnetic energy. A perfect black body in thermodynamic equilibrium absorbs all light that strikes it, and radiates energy according to a unique law of radiative emissive power for temperature (Stefan–Boltzmann law), universal for all perfect black bodies. Kirchhoff's law states that: Here, the dimensionless coefficient of absorption (or the absorptivity) is the fraction of incident light (power) that is absorbed by the body when it is radiating and absorbing in thermodynamic equilibrium. In slightly different terms, the emissive power of an arbitrary opaque body ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Aurora (astronomy)
An aurora (plural: auroras or aurorae), also commonly known as the polar lights, is a natural light display in Earth's sky, predominantly seen in high-latitude regions (around the Arctic and Antarctic). Auroras display dynamic patterns of brilliant lights that appear as curtains, rays, spirals, or dynamic flickers covering the entire sky. Auroras are the result of disturbances in the magnetosphere caused by the solar wind. Major disturbances result from enhancements in the speed of the solar wind from coronal holes and coronal mass ejections. These disturbances alter the trajectories of charged particles in the magnetospheric plasma. These particles, mainly electrons and protons, precipitate into the upper atmosphere ( thermosphere/ exosphere). The resulting ionization and excitation of atmospheric constituents emit light of varying colour and complexity. The form of the aurora, occurring within bands around both polar regions, is also dependent on the amount of accelerat ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Astrophysics
Astrophysics is a science that employs the methods and principles of physics and chemistry in the study of astronomical objects and phenomena. As one of the founders of the discipline said, Astrophysics "seeks to ascertain the nature of the heavenly bodies, rather than their positions or motions in space–''what'' they are, rather than ''where'' they are." Among the subjects studied are the Sun, other stars, galaxies, extrasolar planets, the interstellar medium and the cosmic microwave background. Emissions from these objects are examined across all parts of the electromagnetic spectrum, and the properties examined include luminosity, density, temperature, and chemical composition. Because astrophysics is a very broad subject, ''astrophysicists'' apply concepts and methods from many disciplines of physics, including classical mechanics, electromagnetism, statistical mechanics, thermodynamics, quantum mechanics, relativity, nuclear and particle physics, and atomic and ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Medelpad
Medelpad ( or ) is a historical province or ''landskap'' in the north of Sweden. It borders Hälsingland, Härjedalen, Jämtland, Ångermanland and the Gulf of Bothnia. The province is a part of Norrland and as such considered to be Northern Sweden, although the province geographically is located in the middle of Sweden. It is a common misconception that the name ''Medelpad'' ("middle land" or "middle ground") reflects this, but the name actually refers to the fact that most of the province lies between its two rivers Ljungan and Indalsälven. Administration The traditional provinces of Sweden serve no administrative or political purposes, but are historical and cultural entities. In the case of Medelpad the province roughly comprises the southern part of the administrative county, ''län'', Västernorrland County. Three municipalities have their seats in Medelpad: * Sundsvall * Timrå * Ånge Heraldry The arms of Medelpad symbolises the land between the two ri ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
