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Water Hole (radio)
The waterhole, or water hole, is an especially quiet band of the electromagnetic spectrum between 1420 and 1662 megahertz, corresponding to wavelengths of 21 and 18 centimeters, respectively. 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 involv ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Atmospheric Electromagnetic Opacity
An atmosphere () is a layer of gas or layers of gases that envelop a planet, and is held in place by the gravity of the planetary body. 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 to produce 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, the solar wind, and cosmic rays to protect organisms from genetic damage. The cu ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Radio Noise
In radio reception, radio noise is unwanted random radio frequency electrical signals, fluctuating voltages, always present in a radio receiver in addition to the desired radio signal. Radio noise near in frequency to the radio signal being received (in the receiver's passband) interferes with it in the receiver's circuits. Radio noise is a combination of natural electromagnetic atmospheric noise ("spherics", static) created by electrical processes in the atmosphere like lightning, manmade radio frequency interference (RFI) from other electrical devices picked up by the receiver's antenna, and thermal noise present in the receiver input circuits, caused by the random thermal motion of molecules. The level of noise determines the maximum sensitivity and reception range of a radio receiver; if no noise were picked up with radio signals, even weak transmissions could be received at virtually any distance by making a radio receiver that was sensitive enough. With noise present, if a ... [...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. The concept was introduced by the American economist Thomas Schelling in his book ''The Strategy of Conflict'' (1960). Schelling states that "(p)eople ''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 (at page 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. The most famous one is the New York City question: if you are to meet a stranger in New York City, but you cannot communicate with the person, then when and where will you choose to meet? This is a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Radio Source SHGb02+14a
SHGb02+14a is an astronomical radio source and a candidate in the Search for Extra-Terrestrial Intelligence (SETI), discovered in March 2003 by SETI@home and announced in ''New Scientist'' on September 1, 2004. Observation The source was originally detected by Oliver Voelker of Logpoint in Nuremberg, Germany and Nate Collins of Farin and Associates in Wisconsin, USA using the giant Arecibo Telescope in Puerto Rico. It was observed three times (for a total of about one minute) at a frequency of about 1420 MHz, one of the frequencies in the waterhole region, which is theorized to be a good candidate for frequencies used by extraterrestrial intelligence to broadcast contact signals. There are a number of puzzling features of this candidate, which have led to a large amount of skepticism. The source is located between the constellations Pisces and Aries, a direction in which no stars are observed within 1000 light years from Earth. It is also a very weak signal. The frequency of t ... [...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 the 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 several subsequent attempts by Ehman and others. Many hypotheses have been advanced on the origin of the emission, including natural and human-made sources, but none o ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Search For Extraterrestrial Intelligence
The search for extraterrestrial intelligence (SETI) is a collective term for scientific searches for intelligent extraterrestrial life, for example, monitoring electromagnetic radiation for signs of transmissions from civilizations on other planets. Scientific investigation began shortly after the advent of radio in the early 1900s, and focused international efforts have been ongoing since the 1980s. In 2015, Stephen Hawking and Israeli billionaire Yuri Milner announced a project called Breakthrough Listen. History Early work There have been many earlier searches for extraterrestrial intelligence within the Solar System. In 1896, Nikola Tesla suggested that an extreme version of his wireless electrical transmission system could be used to contact beings on Mars. In 1899, while conducting experiments at his Colorado Springs experimental station, he thought he had detected a signal from Mars since an odd repetitive static signal seemed to cut off when Mars set in the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Vernacular
A vernacular or vernacular language is in contrast with a "standard language". It refers to the language or dialect that is spoken by people that are inhabiting a particular country or region. The vernacular is typically the native language, normally spoken informally rather than written, and seen as of lower status than more codified forms. It may vary from more prestigious speech varieties in different ways, in that the vernacular can be a distinct stylistic register, a regional dialect, a sociolect, or an independent language. Vernacular is a term for a type of speech variety, generally used to refer to a local language or dialect, as distinct from what is seen as a standard language. The vernacular is contrasted with higher-prestige forms of language, such as national, literary, liturgical or scientific idiom, or a '' lingua franca'', used to facilitate communication across a large area. According to another definition, a vernacular is a language that has not deve ... [...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, where animals tend to gather to obtain water. A watering hole is "a sunken area of land that fills with water". Watering holes can form through a number of processes, one being from elephants digging up termite mounds for nutrients in the soil, repeatedly digging at the same location until a depression large enough to hold a substantial amount of water. Watering holes may be ephemeral or seasonal. A common misconception associated with watering holes is that, due to the common need for water, predator animals will not attack prey animals in the vicinity of the watering hole. This trope was exploited, for example, by Rudyard Kipling in ''The Jungle Book'', which describes a "truce" at the watering hole as a plot point. In fact, it has been observed that "lion The lion (''Panthera leo'') is a large cat of the genus '' Panthera'' native to Africa and India. ... [...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: 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 communication, such ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Bernard M
Bernard (''Bernhard'') is a French language, French and West Germanic masculine given name. It 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 reflex was ''Beornheard'', which was replaced by 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). Bernard is the second most common surname in France. Geographical distribution 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), 2.7% of Burundi (1:894), 1.9% of Belgium (1:1,500), 1.6% of Rwanda (1:1,745), 1 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
