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2011 AG5
, provisional designation , is a sub-kilometer asteroid, classified as near-Earth object and potentially hazardous asteroid of the Apollo group. It has a diameter of about . It was removed from the Sentry Risk Table on 21 December 2012 and as such it now has a rating of 0 on the Torino Scale. It was recovered in December 2022 extending the observation arc from 4.8 years to 14 years. As of 2023, the distance between the orbits of Earth and is Description was discovered on 8 January 2011 by the Mount Lemmon Survey at an apparent magnitude of 19.6 using a reflecting telescope. Pan-STARRS precovery images from 8 November 2010 extended the observation arc to 317 days. Observations by the Gemini telescope at Mauna Kea recovered the asteroid on October 20, 21 and 27, 2012, and extended the observation arc to 719 days. The October 2012 observations reduced the orbit uncertainties by more than a factor of 60, meaning that the Earth's position in February 2040 no longer falls ...
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Mount Lemmon Survey
Mount Lemmon Survey (MLS) is a part of the Catalina Sky Survey with List of observatory codes, observatory code List of observatory codes#G96, G96. MLS uses a cassegrain reflector telescope (with 10560x10560-pixel camera at the f/1.6 prime focus, for a five square degree field of view) operated by the Steward Observatory at Mount Lemmon Observatory, which is located at in the Santa Catalina Mountains northeast of Tucson, Arizona. It is currently one of the most prolific surveys worldwide, especially for discovering near-Earth objects. MLS ranks among the top discoverers on the Minor Planet Center's discovery chart with a total of more than 50,000 numbered minor planets. History Andrea Boattini and the survey accidentally rediscovered 206P/Barnard-Boattini, a lost comet, on 7 October 2008. The comet has made 20 revolutions since 1892 and passed within 0.3–0.4 Astronomical unit, AU of Jupiter in 1922, 1934 and 2005. This comet was also the first comet to be discovered b ...
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Curve Fitting
Curve fitting is the process of constructing a curve, or mathematical function, that has the best fit to a series of data points, possibly subject to constraints. Curve fitting can involve either interpolation, where an exact fit to the data is required, or smoothing, in which a "smooth" function is constructed that approximately fits the data. A related topic is regression analysis, which focuses more on questions of statistical inference such as how much uncertainty is present in a curve that is fit to data observed with random errors. Fitted curves can be used as an aid for data visualization, to infer values of a function where no data are available, and to summarize the relationships among two or more variables. Extrapolation refers to the use of a fitted curve beyond the range of the observed data, and is subject to a degree of uncertainty since it may reflect the method used to construct the curve as much as it reflects the observed data. For linear-algebraic analysis o ...
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Palermo Technical Scale
The Palermo Technical Impact Hazard Scale is a logarithmic scale used by astronomers to rate the potential hazard of impact of a near-Earth object (NEO). It combines two types of data—probability of impact and estimated kinetic yield—into a single "hazard" value. A rating of 0 means the hazard is equivalent to the background hazard (defined as the average risk posed by objects of the same size or larger over the years until the date of the potential impact). A rating of +2 would indicate the hazard is 100 times as great as a random background event. Scale values less than −2 reflect events for which there are no likely consequences, while Palermo Scale values between −2 and 0 indicate situations that merit careful monitoring. A similar but less complex scale is the Torino Scale, which is used for simpler descriptions in the non-scientific media. As of December 2022, one asteroid has a cumulative Palermo Scale value above −2: 101955 Bennu (−1.41). Five have cumu ...
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Gravitational Keyhole
A gravitational keyhole is a tiny region of space where a planet's gravity would alter the orbit of a passing asteroid such that the asteroid would collide with that planet on a given future orbital pass. The word "keyhole" contrasts the large uncertainty of trajectory calculations (between the time of the observations of the asteroid and the first encounter with the planet) with the relatively narrow bundle(s) of critical trajectories. The term was coined by P. W. Chodas in 1999. It gained some public interest when it became clear, in January 2005, that the Asteroid 99942 Apophis would miss the Earth in 2029 but may go through one or another keyhole leading to impacts in 2036 or 2037. Further research has since been done, however, which revealed the probability of Apophis passing through the keyhole was extremely low. Keyholes for the nearer or further future are named by the numbers of orbital periods of the planet and the asteroid, respectively, between the two encounters (for ...
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Tsar Bomba
The Tsar Bomba () ( code name: ''Ivan'' or ''Vanya''), also known by the alphanumerical designation "AN602", was a thermonuclear aerial bomb, and the most powerful nuclear weapon ever created and tested. Overall, the Soviet physicist Andrei Sakharov oversaw the project at Arzamas-16, while the main work of design was by Sakharov, Viktor Adamsky, Yuri Babayev, Yuri Smirnov, and Yuri Trutnev. The project was ordered by Nikita Khrushchev in July 1961 as part of the Soviet resumption of nuclear testing after the Test Ban Moratorium, with the detonation timed to coincide with the 22nd Congress of the Communist Party of the Soviet Union. Tested on 30 October 1961, the test verified new design principles for high-yield thermonuclear charges, allowing, as its final report put it, the design of a nuclear device "of practically unlimited power". The bomb was dropped by parachute from a Tu-95V aircraft, and detonated autonomously above the cape Sukhoy Nos of Severny Island, N ...
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Megatons
TNT equivalent is a convention for expressing energy, typically used to describe the energy released in an explosion. The is a unit of energy defined by that convention to be , which is the approximate energy released in the detonation of a metric ton (1,000 kilograms) of TNT. In other words, for each gram of TNT exploded, (or 4184 joules) of energy is released. This convention intends to compare the destructiveness of an event with that of conventional explosive materials, of which TNT is a typical example, although other conventional explosives such as dynamite contain more energy. Kiloton and megaton The "kiloton (of TNT)" is a unit of energy equal to 4.184 terajoules (). The "megaton (of TNT)" is a unit of energy equal to 4.184 petajoules (). The kiloton and megaton of TNT have traditionally been used to describe the energy output, and hence the destructive power, of a nuclear weapon. The TNT equivalent appears in various nuclear weapon control treaties, and has ...
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Lunar Distance (astronomy)
The instantaneous Earth–Moon distance, or distance to the Moon, is the distance from the center of Earth to the center of the Moon. Lunar distance (LD or \Delta_), or Earth–Moon characteristic distance, is a unit of measure in astronomy. More technically, it is the semi-major axis of the geocentric lunar orbit. The lunar distance is on average approximately , or 1.28 light-seconds; this is roughly 30 times Earth's diameter or 9.5 times Earth's circumference. A little less than 400 lunar distances make up an astronomical unit. The semi-major axis has a value of . The time-averaged distance between the centers of Earth and the Moon is . The actual distance varies over the course of the orbit of the Moon, from at the perigee to at apogee, resulting in a differential range of . Lunar distance is commonly used to express the distance to near-Earth object encounters. Lunar semi-major axis is an important astronomical datum; the few millimeter precision of the range measurements ...
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Uncertainty Parameter U
The uncertainty parameter ''U'' is introduced by the Minor Planet Center (MPC) to quantify the uncertainty of a perturbed orbital solution for a minor planet. The parameter is a logarithmic scale from 0 to 9 that measures the anticipated longitudinal uncertainty in the minor planet's mean anomaly after 10 years. The larger the number, the larger the uncertainty. The uncertainty parameter is also known as condition code in JPL's Small-Body Database Browser. The ''U'' value should not be used as a predictor for the uncertainty in the future motion of near-Earth objects. Orbital uncertainty Orbital uncertainty is related to several parameters used in the orbit determination process including the number of observations (measurements), the time spanned by those observations (observation arc), the quality of the observations (e.g. radar vs. optical), and the geometry of the observations. Of these parameters, the time spanned by the observations generally has the greatest effect o ...
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Gemini Observatory
The Gemini Observatory is an astronomical observatory consisting of two 8.1-metre (26.6 ft) telescopes, Gemini North and Gemini South, which are located at two separate sites in Hawaii and Chile, respectively. The twin Gemini telescopes provide almost complete coverage of both the northern and southern skies. They are currently among the largest and most advanced optical/infrared telescopes available to astronomers. ''(See List of largest optical reflecting telescopes)''. The National Science Foundation (NSF) of the United States, the National Research Council of Canada, CONICYT of Chile, MCTI of Brazil, and MCTIP of Argentina own and operate the Gemini Observatory. The NSF is currently (2017) the majority partner, contributing approximately 70% of the funding needed to operate and maintain both telescopes. The operations and maintenance of the observatory is managed by the Association of Universities for Research in Astronomy (AURA), through a cooperative agreement with NSF. ...
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Precovery
In astronomy, precovery (short for pre-discovery recovery) is the process of finding the image of an object in images or photographic plates predating its discovery, typically for the purpose of calculating a more accurate orbit. This happens most often with minor planets, but sometimes a comet, a dwarf planet, a natural satellite, or a star is found in old archived images; even exoplanet precovery observations have been obtained. "Precovery" refers to a pre-discovery image; "recovery" refers to imaging of a body which was lost to our view (as behind the Sun), but is now visible again ''(also see lost minor planet and lost comet)''. Orbit determination requires measuring an object's position on multiple occasions. The longer the interval between observations, the more accurately the orbit can be calculated; however, for a newly discovered object, only a few days' or weeks' worth of measured positions may be available, sufficient only for a preliminary (imprecise) orbit calculatio ...
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Pan-STARRS
The Panoramic Survey Telescope and Rapid Response System (Pan-STARRS1; List of observatory codes, obs. code: IAU code#F51, F51 and Pan-STARRS2 obs. code: IAU code#F52, F52) located at Haleakala Observatory, Hawaii, US, consists of astronomical cameras, telescopes and a computing facility that is Astronomical survey, surveying the sky for moving or variable objects on a continual basis, and also producing accurate astrometry and photometry (astronomy), photometry of already-detected objects. In January 2019 the second Pan-STARRS data release was announced. At 1.6 petabytes, it is the largest volume of astronomical data ever released. Description The Pan-STARRS Project is a collaboration between the University of Hawaii Institute for Astronomy (Hawaii), Institute for Astronomy, MIT Lincoln Laboratory, MHPCC#Maui High Performance Computing Center (MHPCC), Maui High Performance Computing Center and Science Applications International Corporation. Telescope construction was funded b ...
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Reflecting Telescope
A reflecting telescope (also called a reflector) is a telescope that uses a single or a combination of curved mirrors that reflect light and form an image. The reflecting telescope was invented in the 17th century by Isaac Newton as an alternative to the refracting telescope which, at that time, was a design that suffered from severe chromatic aberration. Although reflecting telescopes produce other types of optical aberrations, it is a design that allows for very large diameter objectives. Almost all of the major telescopes used in astronomy research are reflectors. Many variant forms are in use and some employ extra optical elements to improve image quality or place the image in a mechanically advantageous position. Since reflecting telescopes use mirrors, the design is sometimes referred to as a catoptrics, catoptric telescope. From the time of Newton to the 1800s, the mirror itself was made of metal usually speculum metal. This type included Newton's first designs and eve ...
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