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Chinese Pulsar Timing Array
The Five-hundred-meter Aperture Spherical Telescope (FAST; ), nicknamed Tianyan (, lit. "Sky's/Heaven's Eye"), is a radio telescope located in the Dawodang depression (), a natural basin in Pingtang County, Guizhou, southwestern China. FAST has a diameter dish constructed in a natural depression in the landscape. It is the world's largest single-dish telescope. It has a novel design, using an active surface made of 4,500 metal panels which form a moving parabola shape in real time. The cabin containing the antenna feed, feed antenna, suspended on cables above the dish, can move automatically by using winches to steer the instrument to receive signals from different directions. It observes at wavelengths of 10 cm to 4.3 m. Construction of FAST began in 2011. It observed First light (astronomy), first light in September 2016. After three years of testing and commissioning, it was declared fully operational on 11 January 2020. The telescope made its first discovery, o ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Radio Telescope
A radio telescope is a specialized antenna (radio), antenna and radio receiver used to detect radio waves from astronomical radio sources in the sky. Radio telescopes are the main observing instrument used in radio astronomy, which studies the radio frequency portion of the electromagnetic spectrum, just as optical telescopes are used to make observations in the visible light, visible portion of the spectrum in traditional optical astronomy. Unlike optical telescopes, radio telescopes can be used in the daytime as well as at night. Since astronomical radio sources such as planets, stars, nebulas and galaxy, galaxies are very far away, the radio waves coming from them are extremely weak, so radio telescopes require very large antennas to collect enough radio energy to study them, and extremely sensitive receiving equipment. Radio telescopes are typically large Parabolic antenna, parabolic ("dish") antennas similar to those employed in tracking and communicating with satellites an ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Identifying Reliable Sources
Identification or identify may refer to: *Identity document, any document used to verify a person's identity Arts, entertainment and media *Identify (album), ''Identify'' (album) by Got7, 2014 *Identify (song), "Identify" (song), by Natalie Imbruglia, 1999 *Identification (album), ''Identification'' (album), by Benjamin Ingrosso, 2018 * Station identification, or ident, radio or TV stations identifying themselves on-air *''Kill Command'', also known as ''Identify'', a 2016 film Science and technology * Identification (information), for data storage * Identifiability, in statistics * Identification (biology), assigning a taxon to an individual organism * Identification scheme, in metadata, used to identify unique records in a set Social sciences * Identification (psychology), a concept in psychoanalysis * Identification in rhetoric, a rhetorical theory of persuasion * Identification (literature), the audience identifying with a character, or a narrative device See also ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Parabolic Antenna
A parabolic antenna is an antenna that uses a parabolic reflector, a curved surface with the cross-sectional shape of a parabola, to direct the radio waves. The most common form is shaped like a dish and is popularly called a dish antenna or parabolic dish. The main advantage of a parabolic antenna is that it has high directivity. It functions similarly to a searchlight or flashlight reflector to direct radio waves in a narrow beam, or receive radio waves from one particular direction only. Parabolic antennas have some of the highest gains, meaning that they can produce the narrowest beamwidths, of any antenna type. In order to achieve narrow beamwidths, the parabolic reflector must be much larger than the wavelength of the radio waves used, so parabolic antennas are used in the high frequency part of the radio spectrum, at UHF and microwave ( SHF) frequencies, at which the wavelengths are small enough that conveniently sized reflectors can be used. Parabolic antennas a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Active Optics
Active optics is a technology used with reflecting telescopes developed in the 1980s, which actively shapes a telescope's mirrors to prevent deformation due to external influences such as wind, temperature, and mechanical stress. Without active optics, the construction of 8 metre class telescopes is not possible, nor would telescopes with segmented mirrors be feasible. This method is used by, among others, the Nordic Optical Telescope, the New Technology Telescope, the Telescopio Nazionale Galileo and the Keck telescopes, as well as all of the largest telescopes built since the mid-1990s. Active optics is not to be confused with adaptive optics, which operates at a shorter timescale and corrects atmospheric distortions. In astronomy Most modern telescopes are reflectors, with the primary element being a very large mirror. Historically, primary mirrors were quite thick in order to maintain the correct surface figure in spite of forces tending to deform it, like wind and the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Geodesic Dome
A geodesic dome is a hemispherical thin-shell structure (lattice-shell) based on a geodesic polyhedron. The rigid triangular elements of the dome distribute stress throughout the structure, making geodesic domes able to withstand very heavy loads for their size. History The first geodesic dome was designed after World War I by Walther Bauersfeld, chief engineer of Carl Zeiss Jena, an optical company, for a planetarium to house his planetarium projector. An initial, small dome was patented and constructed by the firm of Dykerhoff and Wydmann on the roof of the Carl Zeiss Werke in Jena, Germany. A larger dome, called "The Wonder of Jena", opened to the public on July 18, 1926. Twenty years later, Buckminster Fuller coined the term "geodesic" from field experiments with artist Kenneth Snelson at Black Mountain College in 1948 and 1949. Although Fuller was not the original inventor, he is credited with the U.S. popularization of the idea for which he received on 29 J ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Karst
Karst () is a topography formed from the dissolution of soluble carbonate rocks such as limestone and Dolomite (rock), dolomite. It is characterized by features like poljes above and drainage systems with sinkholes and caves underground. There is some evidence that karst may occur in more weathering-resistant rocks such as quartzite given the right conditions. Subterranean drainage may limit surface water, with few to no rivers or lakes. In regions where the dissolved bedrock is covered (perhaps by debris) or confined by one or more superimposed non-soluble rock strata, distinctive karst features may occur only at subsurface levels and can be totally missing above ground. The study of ''paleokarst'' (buried karst in the stratigraphic column) is important in petroleum geology because as much as 50% of the world's Oil and gas reserves and resource quantification, hydrocarbon reserves are hosted in carbonate rock, and much of this is found in porous karst systems. Etymology ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sinkhole
A sinkhole is a depression or hole in the ground caused by some form of collapse of the surface layer. The term is sometimes used to refer to doline, enclosed depressions that are also known as shakeholes, and to openings where surface water enters into underground passages known as ''ponor'', swallow hole or swallet. A ''cenote'' is a type of sinkhole that exposes groundwater underneath. ''Sink'', and ''stream sink'' are more general terms for sites that drain surface water, possibly by infiltration into sediment or crumbled rock. Most sinkholes are caused by Karst topography, karst processes – the chemical dissolution of carbonate rocks, collapse or suffosion processes. Sinkholes are usually circular and vary in size from tens to hundreds of Metre, meters both in diameter and depth, and vary in form from soil-lined bowls to bedrock-edged chasms. Sinkholes may form gradually or suddenly, and are found worldwide. Formation Natural processes Sinkholes may capture surf ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
The New York Times
''The New York Times'' (''NYT'') is an American daily newspaper based in New York City. ''The New York Times'' covers domestic, national, and international news, and publishes opinion pieces, investigative reports, and reviews. As one of the longest-running newspapers in the United States, the ''Times'' serves as one of the country's Newspaper of record, newspapers of record. , ''The New York Times'' had 9.13 million total and 8.83 million online subscribers, both by significant margins the List of newspapers in the United States, highest numbers for any newspaper in the United States; the total also included 296,330 print subscribers, making the ''Times'' the second-largest newspaper by print circulation in the United States, following ''The Wall Street Journal'', also based in New York City. ''The New York Times'' is published by the New York Times Company; since 1896, the company has been chaired by the Ochs-Sulzberger family, whose current chairman and the paper's publ ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
SETI
Seti or SETI may refer to: Astrobiology * SETI, the search for extraterrestrial intelligence. ** SETI Institute, an astronomical research organization *** SETIcon, a former convention organized by the SETI Institute ** Berkeley SETI Research Center, an astronomical research organization *** SETI@home, a distributed computing project ** Active SETI, the attempt to send messages to intelligent aliens Egyptology * Seti (commander), grandfather of Seti I * Seti (Viceroy of Kush) * Seti I (died 1279 BC), pharaoh * Seti II (died 1197 BC), pharaoh * Seti-Merenptah, a son of Seti II * Seti, son of Amun-her-khepeshef * Sethi, one of List of children of Ramesses II#, the sons of Ramesses II Music * SETI (band), an ambient music band from New York City * SETI (The Kovenant album), ''SETI'' (The Kovenant album), an album by metal band The Kovenant Places * Seti River, a tributary of the Karnali River in Nepal * Seti Gandaki River or Seti River, a tributary of the Trishuli River in Nepal * S ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Dan Werthimer
Dan Werthimer is co-founder and chief scientist of the SETI@home project and directs other UC Berkeley SETI searches at radio, infrared and visible wavelengths, including the Search for Extra-Terrestrial Radio Emissions from Nearby Developed Intelligent Populations (SERENDIP). He is also the principal investigator for the worldwide Collaboration for Astronomy Signal Processing and Electronics Research (CASPER). Werthimer was associate professor in the engineering and physics departments of San Francisco State University and a visiting professor at Beijing Normal University, the University of St. Charles in Marseille, Eotvos University in Budapest. His father, Jerrold Werthimer, was Professor of Journalism at San Francisco State University for many years. Werthimer has taught courses at universities in Peru, Egypt, Ghana, Ethiopia, Zimbabwe, Uganda and Kenya. He has published numerous papers in the fields of SETI, radio astronomy, instrumentation and science education; he is ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Earth & Sky
''Earth & Sky'' was a daily radio series that presented information about science and nature. It began broadcasting in 1991 and ceased operations in 2013. ''EarthSky'' is the ongoing website, serving 21 million users in 2019, according to Google Analytics. History ''Earth & Sky'' was the creation of producers Deborah Byrd and Joel Block, who were also the hosts. Byrd had previously created the radio program '' Star Date'' that began broadcasting in the US in 1978, and Block was ''Star Dates original host. Several producers researched topics, interviewed scientists and wrote radio scripts for the program through the years, including Jorge Salazar and Marc Airhart. The final episode of ''Earth & Sky'' was broadcast on June 2, 2013. President and co-founder Deborah Byrd said that although funding options existed to continue the radio program, a decision was made to stop producing the radio show in order to concentrate on the EarthSky.org website and social media. Content ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
