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Hanny's Voorwerp
, (Dutch for ''Hanny's object'') is a rare type of astronomical object called a quasar ionization echo. It was discovered in 2007 by Dutch schoolteacher Hanny van Arkel while she was participating as a volunteer in the Galaxy Zoo project, part of the Zooniverse group of citizen science websites. Photographically, it appears as a bright blob close to spiral galaxy IC 2497 in the constellation Leo Minor. Description Hanny's Voorwerp (HsV) is about the size of a small galaxy and has a central hole over 16,000 light years across. In an image taken with the Hubble Space Telescope, HsV is colored green, a standard false color that is used to represent the presence of several luminous emission lines of glowing oxygen. HsV has been shown to be at the same distance from Earth as the adjacent galaxy IC 2497, which is about 650 million light-years away. Star birth is occurring in the region of HsV that faces IC 2497. Radio observations indicate that this is due to an outflow of gas from ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
J2000
In astronomy, an epoch or reference epoch is a instant, moment in time used as a reference point for some time-varying astronomical quantity. It is useful for the celestial coordinates or orbital elements of a Astronomical object, celestial body, as they are subject to Perturbation (astronomy), perturbations and vary with time. These time-varying astronomical quantities might include, for example, the mean longitude or mean anomaly of a body, the node of its orbit relative to a reference plane, the direction of the apogee or Perihelion and aphelion, aphelion of its orbit, or the size of the major axis of its orbit. The main use of astronomical quantities specified in this way is to calculate other relevant parameters of motion, in order to predict future positions and velocities. The applied tools of the disciplines of celestial mechanics or its subfield orbital mechanics (for predicting orbital paths and positions for bodies in motion under the gravitational effects of other bodi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
False Color
False color (or pseudo color) refers to a group of color rendering methods used to display images in color which were recorded in the visible or non-visible parts of the electromagnetic spectrum. A false-color image is an image that depicts an object in colors that differ from those a photograph (a true-color image) would show. In this image, colors have been assigned to three different wavelengths that our eyes cannot normally see. In addition, variants of ''false color'' such as pseudocolor, density slicing, and choropleths are used for information visualization of either data gathered by a single grayscale channel or data not depicting parts of the electromagnetic spectrum (e.g. elevation in relief maps or tissue types in magnetic resonance imaging). Types of color renderings True color The concept behind true color can help in understanding false color. An image is called a ''true-color'' image when it offers a natural color rendition, or when it comes close to it. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Phys
Physics is the natural science that studies matter, its fundamental constituents, its motion and behavior through space and time, and the related entities of energy and force. "Physical science is that department of knowledge which relates to the order of nature, or, in other words, to the regular succession of events." Physics is one of the most fundamental scientific disciplines, with its main goal being to understand how the universe behaves. "Physics is one of the most fundamental of the sciences. Scientists of all disciplines use the ideas of physics, including chemists who study the structure of molecules, paleontologists who try to reconstruct how dinosaurs walked, and climatologists who study how human activities affect the atmosphere and oceans. Physics is also the foundation of all engineering and technology. No engineer could design a flat-screen TV, an interplanetary spacecraft, or even a better mousetrap without first understanding the basic laws of physics. (. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Transient Astronomical Event
The asterisk ( ), from Late Latin , from Ancient Greek , ''asteriskos'', "little star", is a typographical symbol. It is so called because it resembles a conventional image of a heraldic star. Computer scientists and mathematicians often vocalize it as star (as, for example, in ''the A* search algorithm'' or ''C*-algebra''). In English, an asterisk is usually five- or six-pointed in sans-serif typefaces, six-pointed in serif typefaces, and six- or eight-pointed when handwritten. Its most common use is to call out a footnote. It is also often used to censor offensive words. In computer science, the asterisk is commonly used as a wildcard character, or to denote pointers, repetition, or multiplication. History The asterisk has already been used as a symbol in ice age cave paintings. There is also a two thousand-year-old character used by Aristarchus of Samothrace called the , , which he used when proofreading Homeric poetry to mark lines that were duplicated. Origen is know ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Annual Review Of Astronomy And Astrophysics
The ''Annual Review of Astronomy and Astrophysics'' is an annual peer reviewed scientific journal published by Annual Reviews. The co-editors are Ewine van Dishoeck and Robert C. Kennicutt. The journal reviews scientific literature pertaining to local and distant celestial entities throughout the observable universe, as well as cosmology, instrumentation, techniques, and the history of developments. It was established in 1963. History In November of 1960, the board of directors of the nonprofit publisher Annual Reviews began investigating the need for a new journal of review articles that covered developments in astronomy and astrophysics. The board consulted an advisory group of experts, including Ronald Bracewell, Robert Jastrow, Joseph Kaplan, Paul Merrill, Otto Struve, and Harold Urey. The editorial committee met in August 1961 to determine the authors and topics for the first volume, which was published in 1963. As of 2020, it was published both in print and electronicall ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
The Economist
''The Economist'' is a British weekly newspaper printed in demitab format and published digitally. It focuses on current affairs, international business, politics, technology, and culture. Based in London, the newspaper is owned by The Economist Group, with its core editorial offices in the United States, as well as across major cities in continental Europe, Asia, and the Middle East. In 2019, its average global print circulation was over 909,476; this, combined with its digital presence, runs to over 1.6 million. Across its social media platforms, it reaches an audience of 35 million, as of 2016. The newspaper has a prominent focus on data journalism and interpretive analysis over original reporting, to both criticism and acclaim. Founded in 1843, ''The Economist'' was first circulated by Scottish economist James Wilson to muster support for abolishing the British Corn Laws (1815–1846), a system of import tariffs. Over time, the newspaper's coverage expanded further into ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hypothesis
A hypothesis (plural hypotheses) is a proposed explanation for a phenomenon. For a hypothesis to be a scientific hypothesis, the scientific method requires that one can test it. Scientists generally base scientific hypotheses on previous observations that cannot satisfactorily be explained with the available scientific theories. Even though the words "hypothesis" and "theory" are often used interchangeably, a scientific hypothesis is not the same as a scientific theory. A working hypothesis is a provisionally accepted hypothesis proposed for further research in a process beginning with an educated guess or thought. A different meaning of the term ''hypothesis'' is used in formal logic, to denote the antecedent of a proposition; thus in the proposition "If ''P'', then ''Q''", ''P'' denotes the hypothesis (or antecedent); ''Q'' can be called a consequent. ''P'' is the assumption in a (possibly counterfactual) ''What If'' question. The adjective ''hypothetical'', meaning "hav ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Atlanta
Atlanta ( ) is the capital and most populous city of the U.S. state of Georgia. It is the seat of Fulton County, the most populous county in Georgia, but its territory falls in both Fulton and DeKalb counties. With a population of 498,715 living within the city limits, it is the eighth most populous city in the Southeast and 38th most populous city in the United States according to the 2020 U.S. census. It is the core of the much larger Atlanta metropolitan area, which is home to more than 6.1 million people, making it the eighth-largest metropolitan area in the United States. Situated among the foothills of the Appalachian Mountains at an elevation of just over above sea level, it features unique topography that includes rolling hills, lush greenery, and the most dense urban tree coverage of any major city in the United States. Atlanta was originally founded as the terminus of a major state-sponsored railroad, but it soon became the convergence point among several rai ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Dragon Con
Dragon Con (previously Dragon*Con and sometimes DragonCon) is a North American multigenre convention, founded in 1987, which takes place annually over the Labor Day weekend in Atlanta, Georgia. , the convention draws attendance of over 80,000, features hundreds of guests, encompasses five hotels in the Peachtree Center neighborhood of downtown Atlanta near Centennial Olympic Park, and runs thousands of hours of programming for fans of science fiction, fantasy, comic books, and other elements of fan culture. It is owned and operated by a private for-profit corporation, with the help of a 1,500-member volunteer staff. Dragon Con has hosted the 1990 Origins Game Fair and the 1995 North American Science Fiction Convention (NASFiC). History Dragon Con was launched in 1987, as a project of a local science fiction and gaming group, the Dragon Alliance of Gamers and Role-Players (DAGR). It was founded by a board of directors including John Bunnell, David Cody, Robert Dennis, Mike Helb ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
European Southern Observatory
The European Organisation for Astronomical Research in the Southern Hemisphere, commonly referred to as the European Southern Observatory (ESO), is an intergovernmental organization, intergovernmental research organisation made up of 16 member states for ground-based astronomy. Created in 1962, ESO has provided astronomers with state-of-the-art research facilities and access to the southern sky. The organisation employs about 730 staff members and receives annual member state contributions of approximately €162 million. Its observatories are located in northern Chile. ESO has built and operated some of the largest and most technologically advanced telescopes. These include the 3.6 m New Technology Telescope, an early pioneer in the use of active optics, and the Very Large Telescope (VLT), which consists of four individual 8.2 m telescopes and four smaller auxiliary telescopes which can all work together or separately. The Atacama Large Millimeter Array observes the un ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Stellar Evolution
Stellar evolution is the process by which a star changes over the course of time. Depending on the mass of the star, its lifetime can range from a few million years for the most massive to trillions of years for the least massive, which is considerably longer than the age of the universe. The table shows the lifetimes of stars as a function of their masses. All stars are formed from collapsing clouds of gas and dust, often called nebulae or molecular clouds. Over the course of millions of years, these protostars settle down into a state of equilibrium, becoming what is known as a main-sequence star. Nuclear fusion powers a star for most of its existence. Initially the energy is generated by the fusion of hydrogen atoms at the core of the main-sequence star. Later, as the preponderance of atoms at the core becomes helium, stars like the Sun begin to fuse hydrogen along a spherical shell surrounding the core. This process causes the star to gradually grow in size, passing throug ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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