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Waterhole (radio)
The waterhole, or water hole, is an especially quiet band of the electromagnetic spectrum between 1420 and 1662 megahertz, corresponding to wavelengths of 18–21 centimeters. It is a popular observing frequency used by radio telescopes in radio astronomy. The strongest hydroxyl radical spectral line radiates at 18 centimeters, and atomic hydrogen at 21 centimeters (the hydrogen line). These two molecules, which combine to form water, are widespread in interstellar gas, which means this gas tends to absorb radio noise at these frequencies. Therefore, the spectrum between these frequencies forms a relatively "quiet" channel in the interstellar radio noise background. Bernard M. Oliver, who coined the term in 1971, theorized that the waterhole would be an obvious band for communication with extraterrestrial intelligence, hence the name, which is a pun: in English, a watering hole is a vernacular reference to a common place to meet and talk. Several programs involved in the searc ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Atmospheric Electromagnetic Opacity
An atmosphere () is a layer of gases that envelop an astronomical object, held in place by the gravity of the object. A planet retains an atmosphere when the gravity is great and the temperature of the atmosphere is low. A stellar atmosphere is the outer region of a star, which includes the layers above the opaque photosphere; stars of low temperature might have outer atmospheres containing compound molecules. The atmosphere of Earth is composed of nitrogen (78%), oxygen (21%), argon (0.9%), carbon dioxide (0.04%) and trace gases. Most organisms use oxygen for respiration; lightning and bacteria perform nitrogen fixation which produces ammonia that is used to make nucleotides and amino acids; plants, algae, and cyanobacteria use carbon dioxide for photosynthesis. The layered composition of the atmosphere minimises the harmful effects of sunlight, ultraviolet radiation, solar wind, and cosmic rays and thus protects the organisms from genetic damage. The current composition o ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Radio Noise
In radio reception, radio noise (commonly referred to as radio static) is unwanted random radio frequency electrical signals, fluctuating voltages, always present in a radio receiver in addition to the desired radio signal. Radio noise is a combination of natural electromagnetic atmospheric noise ("spherics", static) created by electrical processes in the atmosphere like lightning; human-made radio frequency interference () from other electrical devices picked up by the receiver's antenna (radio), antenna; and thermal noise present in the receiver input circuits, mostly caused by the random thermal motion of molecules inside resistors. Effects of noise on radio Radio noise near in frequency to a received radio signal (in the receiver's passband) radio frequency interference, interferes (radio frequency interference, ) with the operation of the receiver's circuitry. The level of noise determines the maximum sensitivity and reception range of a radio receiver; if no noise were pi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Schelling Point
In game theory, a focal point (or Schelling point) is a solution that people tend to choose by default in the absence of communication in order to avoid coordination failure. The concept was introduced by the American economist Thomas Schelling in his book ''The Strategy of Conflict'' (1960). Schelling states that " ople ''can'' often concert their intentions or expectations with others if each knows that the other is trying to do the same" in a cooperative situation (p. 57), so their action would converge on a focal point which has some kind of prominence compared with the environment. However, the conspicuousness of the focal point depends on time, place and people themselves. It may not be a definite solution. Existence The existence of the focal point is first demonstrated by Schelling with a series of questions. Here is one example: to determine the time and place to meet a stranger in New York City, but without being able to communicate in person beforehand. In this coordin ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Radio Source SHGb02+14a
Radio is the technology of communicating using radio waves. Radio waves are electromagnetic waves of frequency between 3 hertz (Hz) and 300 gigahertz (GHz). They are generated by an electronic device called a transmitter connected to an antenna which radiates the waves. They can be received by other antennas connected to a radio receiver; this is the fundamental principle of radio communication. In addition to communication, radio is used for radar, radio navigation, remote control, remote sensing, and other applications. In radio communication, used in radio and television broadcasting, cell phones, two-way radios, wireless networking, and satellite communication, among numerous other uses, radio waves are used to carry information across space from a transmitter to a receiver, by modulating the radio signal (impressing an information signal on the radio wave by varying some aspect of the wave) in the transmitter. In radar, used to locate and track objects like air ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Wow! Signal
The Wow! signal was a strong narrowband radio signal detected on August 15, 1977, by Ohio State University's Big Ear radio telescope in the United States, then used to support the search for extraterrestrial intelligence. The signal appeared to come from the direction of the constellation Sagittarius and bore expected hallmarks of extraterrestrial origin. Astronomer Jerry R. Ehman discovered the anomaly a few days later while reviewing the recorded data. He was so impressed by the result that he circled on the computer printout the reading of the signal's intensity, "6EQUJ5", and wrote the comment "Wow!" beside it, leading to the event's widely used name. The entire signal sequence lasted for the full 72-second window during which Big Ear was able to observe it, but has not been detected since, despite many subsequent attempts by Ehman and others. Several hypotheses have been advanced on the origin of the emission, including natural and human-made sources. Background I ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
BLC1
BLC1 (''Breakthrough Listen Candidate 1'') was a candidate SETI radio signal detected and observed during April and May 2019, and first reported on 18 December 2020, spatially coincident with the direction of the Solar System's closest neighboring star, Proxima Centauri. Signal The apparent shift in its frequency, consistent with the Doppler effect, was suggested to be inconsistent with what would be caused by the movement of Proxima b, a planet of Proxima Centauri. The Doppler shift in the signal was the opposite of what would be expected from the Earth's spin, in that the signal was observed to increase in frequency rather than decrease. Although the signal was detected by Parkes Radio Telescope during observations of Proxima Centauri, due to the beam angle of Parkes Radio telescope, the signal would be more accurately described as having come from within a circle roughly 16 arcminutes (approximately 1/4 of a degree, half the angular width of Earth's moon) in angular diameter, c ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
SETI@home
SETI@home ("SETI at home") is a project of the Berkeley SETI Research Center to analyze radio signals with the aim of Search for extraterrestrial intelligence, searching for signs of extraterrestrial intelligence. Until March 2020, it was run as an Internet-based public volunteer computing project that employed the Berkeley Open Infrastructure for Network Computing, BOINC software platform. It is hosted by the Space Sciences Laboratory at the University of California, Berkeley, and is one of many activities undertaken as part of the worldwide SETI effort. SETI@home software was released to the public on May 17, 1999, making it the third large-scale use of volunteer computing over the Internet for research purposes, after Great Internet Mersenne Prime Search (GIMPS) was launched in 1996 and distributed.net in 1997. Along with MilkyWay@home and Einstein@home, it is the third major computing project of this type that has the investigation of phenomena in interstellar space as its ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Search For Extraterrestrial Intelligence
The search for extraterrestrial intelligence (usually shortened as SETI) is an expression that refers to the diverse efforts and scientific projects intended to detect extraterrestrial signals, or any evidence of intelligent life beyond Earth. Researchers use methods such as monitoring electromagnetic radiation, searching for optical signals, and investigating potential extraterrestrial artifacts for any signs of transmission from civilizations present on other planets. Some initiatives have also attempted to send messages to hypothetical alien civilizations, such as NASA's Voyager Golden Record, Golden Record. Modern SETI research began in the early 20th century after the advent of radio, expanding with projects like Project Ozma, the Wow! signal detection, and the Breakthrough Listen initiative; a $100 million, 10-year attempt to detect signals from nearby stars, announced in 2015 by Stephen Hawking and Yuri Milner. Since the 1980s, international efforts have been ongoing, wit ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Vernacular
Vernacular is the ordinary, informal, spoken language, spoken form of language, particularly when perceptual dialectology, perceived as having lower social status or less Prestige (sociolinguistics), prestige than standard language, which is more codification (linguistics), codified, institutionally promoted, literary language, literary, or formal. More narrowly, a particular language variety that does not hold a widespread high-status perception, and sometimes even carries social stigma, is also called a vernacular, vernacular dialect, nonstandard dialect, etc. and is typically its speakers' native language, native variety. Regardless of any such stigma, all nonstandard dialects are full-fledged varieties of language with their own consistent grammatical structure, phonology, sound system, body of vocabulary, etc. Overview Like any native language variety, a vernacular has an internally coherent system of grammar. It may be associated with a particular set of vocabulary, and sp ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Watering Hole
A watering hole or waterhole is a geological depression in which a body of water forms, usually a pond or a small lake. A watering hole is "a sunken area of land that fills with water". Watering holes may be ephemeral or seasonal. Ephemeral rivers sometimes form waterholes in geological depressions or areas scoured by erosion, and are common in arid regions of Australia. In Australia, the term " billabong", often defined as a type of oxbow lake (an isolated crescentic pond left behind after a river loop is cut off when the river channel changes course), is also used to refer to other types of waterholes. While they exist in both wetlands and arid lands, they are of particular importance in desert areas of Australia, where they are often the only water source for native animals, people, and livestock, and provide critical habitat for a number of wildlife species. Their existence is being threatened by climate change. Desert waterholes are often found in dry hilly areas, sust ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Communication With Extraterrestrial Intelligence
The communication with extraterrestrial intelligence (CETI) is a branch of the search for extraterrestrial intelligence (SETI) that focuses on composing and deciphering interstellar messages that theoretically could be understood by another technological civilization. The best-known CETI experiment of its kind was the 1974 Arecibo message composed by Frank Drake. There are multiple independent organizations and individuals engaged in CETI research; the generic application of abbreviations CETI and SETI (search for extraterrestrial intelligence) in this article should not be taken as referring to any particular organization (such as the SETI Institute). CETI research has focused on four broad areas: mathematics, mathematical languages, pictorial systems such as the Arecibo message, algorithmic communication systems (ACETI), and computational approaches to detecting and deciphering "natural" language communication. There remain many undeciphered writing systems in human communicat ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Bernard M
Bernard (''Bernhard'') is a French and West Germanic masculine given name. It has West Germanic origin and is also a surname. The name is attested from at least the 9th century. West Germanic ''Bernhard'' is composed from the two elements ''bern'' "bear" and ''hard'' "brave, hardy". Its native Old English cognate was ''Beornheard'', which was replaced or merged with the French form ''Bernard'' that was brought to England after the Norman Conquest. The name ''Bernhard'' was notably popular among Old Frisian speakers. Its wider use was popularized due to Saint Bernhard of Clairvaux (canonized in 1174). In Ireland, the name was an anglicized form of Brian. Geographical distribution Bernard is the second most common surname in France. As of 2014, 42.2% of all known bearers of the surname ''Bernard'' were residents of France (frequency 1:392), 12.5% of the United States (1:7,203), 7.0% of Haiti (1:382), 6.6% of Tanzania (1:1,961), 4.8% of Canada (1:1,896), 3.6% of Nigeria (1:12,221) ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
