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Experiment To Detect The Global EoR Signature
The Experiment to Detect the Global EoR Signature (EDGES) is an experiment and radio telescope located in a radio quiet zone at the Murchison Radio-astronomy Observatory in Western Australia. It is a collaboration between Arizona State University and Haystack Observatory, with infrastructure provided by CSIRO. EoR stands for epoch of reionization, a time in cosmic history when neutral atomic hydrogen gas became ionised due to ultraviolet light from the first stars. Low-band instruments The experiment has two low-band instruments, each of which has a dipole antenna pointed to the zenith and observing a single polarisation. The antenna is around in size, sat on a ground shield. It is coupled with a radio receiver, with a 100m cable run to a digital spectrometer. The instruments operate at , and are separated by 150m. Observations started in August 2015. 78 MHz absorption profile In March 2018 the collaboration published a paper in ''Nature'' announcing the discovery of a br ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Radio Quiet Zone
A radio quiet zone is an area where radio transmissions are restricted in order to protect a radio telescope or a communications station from radio frequency interference. The Radio Regulations of the International Telecommunication Union (ITU) define interference as being detrimental to radio astronomy if it increases measurement uncertainty by 10%. In particular, the applicable regulation is known as ITU-R Recommendation RA.769, "Protection criteria used for radio astronomical measurements". Equipment that can cause interference includes mobile phones, television transmitters, and CB radios, as well as other electrical equipment. Quiet zones are located in areas that are sparsely populated, and may be enforced by government legislation. A radio quiet zone is often divided into two zones: an exclusion zone where all radio emissions are prohibited, and a larger coordination zone of up to 100 km2 where the power levels of radio transmissions are suitably limited so as not to i ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Wouthuysen–Field Coupling
Wouthuysen–Field coupling, or the Wouthuysen–Field effect, is a mechanism that couples the excitation temperature, also called the spin temperature, of neutral hydrogen to Lyman-alpha radiation. This coupling plays a role in producing a difference in the temperature of neutral hydrogen and the cosmic microwave background at the end of the Dark Ages and the beginning of the epoch of reionization. It is named for Siegfried Adolf Wouthuysen and George B. Field. Background The period after recombination occurred and before stars and galaxies formed is known as the "dark ages". During this time, the majority of matter in the universe is neutral hydrogen. This hydrogen has yet to be observed, but there are experiments underway to detect the hydrogen line produced during this era. The hydrogen line is produced when an electron in a neutral hydrogen atom is excited to the triplet spin state, or de-excited as the electron and proton spins go to the singlet state. The energy diff ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Physical Cosmology
Physical cosmology is a branch of cosmology concerned with the study of cosmological models. A cosmological model, or simply cosmology, provides a description of the largest-scale structures and dynamics of the universe and allows study of fundamental questions about its Cosmogony, origin, structure, Chronology of the universe, evolution, and ultimate fate.For an overview, see Cosmology as a science originated with the Copernican principle, which implies that astronomical object, celestial bodies obey identical physical laws to those on Earth, and Newtonian mechanics, which first allowed those physical laws to be understood. Physical cosmology, as it is now understood, began with the development in 1915 of Albert Einstein's general relativity, general theory of relativity, followed by major observational discoveries in the 1920s: first, Edwin Hubble discovered that the universe contains a huge number of external Galaxy, galaxies beyond the Milky Way; then, work by Vesto Sli ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Quanta Magazine
''Quanta Magazine'' is an editorially independent online publication of the Simons Foundation covering developments in physics, mathematics, biology and computer science. ''Undark Magazine'' described ''Quanta Magazine'' as "highly regarded for its masterful coverage of complex topics in science and math." The science news aggregator ''RealClearScience'' ranked ''Quanta Magazine'' first on its list of "The Top 10 Websites for Science in 2018." In 2020, the magazine received a National Magazine Award for General Excellence from the American Society of Magazine Editors for its "willingness to tackle some of the toughest and most difficult topics in science and math in a language that is accessible to the lay reader without condescension or oversimplification." The articles in the magazine are freely available to read online. ''Scientific American'', ''Wired'', ''The Atlantic'', and ''The Washington Post'', as well as international science publications like ''Spektrum der Wissensch ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
List Of Radio Telescopes
This is a list of radio telescopes – over one hundred – that are or have been used for radio astronomy. The list includes both single dishes and interferometric arrays. The list is sorted by region, then by name; unnamed telescopes are in reverse size order at the end of the list. The first radio telescope was invented in 1932, when Karl Jansky at Bell Telephone Laboratories observed radiation coming from the Milky Way. Africa Antarctica Asia Australia Europe North America South America Arctic Ocean Atlantic Ocean Indian Ocean Pacific Ocean Space-based Under construction or planned construction Proposed telescopes Gallery of big dishes File:FastTelescope*8sep2015.jpg, alt=Five hundred meter Aperture Spherical Telescope under construction, The 500 meter Five hundred meter Aperture Spherical Telescope (FAST), under construction, China (2016) File:GBT.png, alt=Green Bank Telescope, The 100 meter Green Bank Telescope, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
List Of Astronomical Societies
A list of notable groups devoted to promoting astronomy research and education. Africa * African Astronomical Society South Africa *Astronomical Society of Southern Africa Asia China * Chinese Astronomical Society India * Akash Mitra Mandal *Astronomical Society of India *Bangalore Astronomical Society (BAS) *Confederation of Indian Amateur Astronomers * IUCAA * Jyotirvidya Parisanstha *Khagol Mandal * Khagol Vishwa Europe * European Astronomical Society * European Association for Astronomy Education France *Société astronomique de France * Société Française d'Astronomie et d'Astrophysique (SF2A) Germany * Astronomische Gesellschaft Greece *Hellenic Astronomical Society Ireland * Irish Astronomical Society * Irish Federation of Astronomical Societies Italy * Unione Astrofili Italiani Norway *Norwegian Astronomical Society Poland *Polish Astronomical Society Serbia *Astronomical Society Ruđer Bošković Turkey *Spaceturk United Kingdom *Airdrie Astronomical A ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
List Of Astronomical Observatories
This is a list of astronomical observatories ordered by name, along with initial dates of operation (where an accurate date is available) and location. The list also includes a final year of operation for many observatories that are no longer in operation. While other sciences, such as volcanology and meteorology, also use facilities called observatories for research and observations, this list is limited to observatories that are used to observe celestial objects. Astronomical observatories are mainly divided into four categories: space-based, airborne, ground-based, and underground-based. Many modern telescopes and observatories are located in space to observe astronomical objects in wavelengths of the electromagnetic spectrum that cannot penetrate the Earth's atmosphere (such as ultraviolet radiation, X-rays, and gamma rays) and are thus impossible to observe using ground-based telescopes. Being above the atmosphere, these space observatories can also avoid the effects of atmo ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
ARCADE
Arcade most often refers to: * Arcade game, a coin-operated game machine ** Arcade cabinet, housing which holds an arcade game's hardware ** Arcade system board, a standardized printed circuit board * Amusement arcade, a place with arcade games * Arcade (architecture), a series of adjoining arches * Shopping mall, one or more buildings forming a complex of shops, also sometimes called a shopping arcade Arcade or The Arcade may also refer to: Places Greece *Arcades (Crete), a town and city-state of ancient Crete, Greece Italy * Arcade, Italy, a town and commune in the region of Veneto United States * Arcade Building (Asheville, North Carolina) * Arden-Arcade, California * Arcade, Georgia, a city in Jackson County * Arcade (village), New York * Arcade (town), New York * The Arcade (Oak Bluffs, Massachusetts), a historic site in Oak Bluffs, Massachusetts * The Arcade (Providence, Rhode Island), a historic shopping center * Arcade, Texas Arts and entertainment Books and comics ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Large Aperture Experiment To Detect The Dark Ages
The Large-Aperture Experiment to Detect the Dark Ages (LEDA) is designed to detect the spectrum of the 21 cm Hydrogen line from the Intergalactic Medium (IGM) at redshifts of 15-30, when the Universe was just ~1% of its present age. It is located at the Long Wavelength Array site, adjacent to the Very Large Array. LEDA principally comprises a "large-N" array correlator (512 inputs over ~ 60 MHz), calibration & imaging system, and instrumentation for measurement of calibrated total-power. These systems will use the station 1 of the Long Wavelength Array as an aperture. LEDA is one of several efforts seeking to study cosmological reionization and the preceding Dark Ages. Others include the Precision Array for Probing the Epoch of Reionization (PAPER), Low Frequency Array (LOFAR), Murchison Widefield Array (MWA), and Giant Metrewave Radio Telescope (GMRT). LEDA will feature array-based calibration to improve the accuracy of foreground subtraction from the total-power sig ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Raman Research Institute
The Raman Research Institute (RRI) is an institute for scientific research located in Bangalore, India. It was founded by Nobel laureate C. V. Raman in 1948. Although it began as an institute privately owned by Sir C. V. Raman, it is now funded by the government of India. History Before Raman considered founding a research institute, he had approached the former Maharaja of Mysore seeking land to build office and conference premises for the Indian Academy of Sciences (IAS). The Maharaja acceded to Raman's request and a plot of land in the Malleshwaram suburb of Bangalore was allotted to the Indian Academy of Sciences in 1934. However, the Academy (then headed by Raman) made no use of the land for seven years. According to the terms of the deal with the Maharaja, the land could be to another use by the government of Mysore if it still remained unused at the end of 1941. Raman, as President of the IAS, held an extraordinary meeting of the academy in 1941, and proposed that a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Baryon
In particle physics, a baryon is a type of composite subatomic particle which contains an odd number of valence quarks (at least 3). Baryons belong to the hadron family of particles; hadrons are composed of quarks. Baryons are also classified as fermions because they have half-integer spin. The name "baryon", introduced by Abraham Pais, comes from the Greek word for "heavy" (βαρύς, ''barýs''), because, at the time of their naming, most known elementary particles had lower masses than the baryons. Each baryon has a corresponding antiparticle (antibaryon) where their corresponding antiquarks replace quarks. For example, a proton is made of two up quarks and one down quark; and its corresponding antiparticle, the antiproton, is made of two up antiquarks and one down antiquark. Because they are composed of quarks, baryons participate in the strong interaction, which is mediated by particles known as gluons. The most familiar baryons are protons and neutrons, both of which ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Dark Matter
Dark matter is a hypothetical form of matter thought to account for approximately 85% of the matter in the universe. Dark matter is called "dark" because it does not appear to interact with the electromagnetic field, which means it does not absorb, reflect, or emit electromagnetic radiation and is, therefore, difficult to detect. Various astrophysical observationsincluding gravitational effects which cannot be explained by currently accepted theories of gravity unless more matter is present than can be seenimply dark matter's presence. For this reason, most experts think that dark matter is abundant in the universe and has had a strong influence on its structure and evolution. The primary evidence for dark matter comes from calculations showing that many galaxies would behave quite differently if they did not contain a large amount of unseen matter. Some galaxies would not have formed at all and others would not move as they currently do. Other lines of evidence include observa ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
