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2018 UA
2018 UA is a small near-Earth Apollo asteroid that flew very close to the Earth on 19 October 2018. It was discovered about 90 minutes before closest approach. After A106fgF Below is the list of asteroid close approaches to Earth in 2018. Timeline of known close approaches less than one lunar distance from Earth A list of known near-Earth asteroid close approaches less than 1 lunar distance () from Earth in 201 ..., it was probably the second closest non-impacting approach of an asteroid in 2018. External links Asteroid 2018 UA flew past Earth at 0.04 LD, 4th closest on record Truck-size asteroid makes fourth-closest pass by Earth on recordSmall asteroid passed closer than TV satellitesMinor Planet Center * * * # Minor planet object articles (unnumbered) Near-Earth objects in 2018 Astronomical objects discovered in 2018 {{NE-asteroid-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Astronomical Unit
The astronomical unit (symbol: au, or or AU) is a unit of length, roughly the distance from Earth to the Sun and approximately equal to or 8.3 light-minutes. The actual distance from Earth to the Sun varies by about 3% as Earth orbits the Sun, from a maximum (aphelion) to a minimum (perihelion) and back again once each year. The astronomical unit was originally conceived as the average of Earth's aphelion and perihelion; however, since 2012 it has been defined as exactly (see below for several conversions). The astronomical unit is used primarily for measuring distances within the Solar System or around other stars. It is also a fundamental component in the definition of another unit of astronomical length, the parsec. History of symbol usage A variety of unit symbols and abbreviations have been in use for the astronomical unit. In a 1976 resolution, the International Astronomical Union (IAU) had used the symbol ''A'' to denote a length equal to the astronomical ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Julian Year (astronomy)
In astronomy, a Julian year (symbol: a or aj) is a unit of measurement of time defined as exactly 365.25 days of SI seconds each.P. Kenneth Seidelmann, ed.''The explanatory supplement to the Astronomical Almanac'' (Mill Valley, Cal.: University Science Books, 1992), pp. 8, 696, 698–9, 704, 716, 730. Reprinted from the "IAU Style Manual" by G.A. Wilkinson, Comm. 5, in IAU Transactions XXB (1987).Harold Rabinowitz and Suzanne Vogel''The manual of scientific style''(Burlington, MA: Academic Press, 2009) 369. The length of the Julian year is the average length of the year in the Julian calendar that was used in Western societies until the adoption of the Gregorian Calendar, and from which the unit is named. Nevertheless, because astronomical Julian years are measuring duration rather than designating dates, this Julian year does not correspond to years in the Julian calendar or any other calendar. Nor does it correspond to the many other ways of defining a year. Usage The J ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Degree (angle)
A degree (in full, a degree of arc, arc degree, or arcdegree), usually denoted by ° (the degree symbol), is a measurement of a plane (mathematics), plane angle in which one Turn (geometry), full rotation is 360 degrees. It is not an SI unit—the SI unit of angular measure is the radian—but it is mentioned in the SI Brochure, SI brochure as an Non-SI units mentioned in the SI, accepted unit. Because a full rotation equals 2 radians, one degree is equivalent to radians. History The original motivation for choosing the degree as a unit of rotations and angles is unknown. One theory states that it is related to the fact that 360 is approximately the number of days in a year. Ancient astronomers noticed that the sun, which follows through the ecliptic path over the course of the year, seems to advance in its path by approximately one degree each day. Some ancient calendars, such as the Iranian calendar, Persian calendar and the Babylonian calendar, used 360 days for a year. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Near-Earth Object
A near-Earth object (NEO) is any small Solar System body whose orbit brings it into proximity with Earth. By convention, a Solar System body is a NEO if its closest approach to the Sun (perihelion) is less than 1.3 astronomical units (AU). If a NEO's orbit crosses the Earth's orbit, and the object is larger than across, it is considered a potentially hazardous object (PHO). Most known PHOs and NEOs are asteroids, but a small fraction are comets. There are over 30,503 known near-Earth asteroids (NEAs) and over a hundred known short-period near-Earth comets (NECs). A number of solar-orbiting meteoroids were large enough to be tracked in space before striking the Earth. It is now widely accepted that collisions in the past have had a significant role in shaping the geological and biological history of the Earth. Asteroids as small as in diameter can cause significant damage to the local environment and human populations. Larger asteroids penetrate the atmosphere to the surf ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
A106fgF
Below is the list of asteroid close approaches to Earth in 2018. Timeline of known close approaches less than one lunar distance from Earth A list of known near-Earth asteroid close approaches less than 1 lunar distance () from Earth in 2018.For a list of current Earth close approaches seNEO Earth Close Approaches/ref> For reference, the radius of Earth is approximately or 0.0166 lunar distances.Geosynchronous satellites have an orbit with semi-major axis length of or 0.110 lunar distances. Eight known asteroids ( 2018 BD, A106fgF, 2018 LA, A107j4q, , 2018 UA, , and ) are confirmed to have passed within this distance, and poorly-observed asteroids ZB0A262, , ZGBE54F, A1080DC , ZW87F01, and ZW900BE may have also passed within this distance. While most asteroids on this list are confirmed, well-observed unconfirmed objects with a 50% or greater chance of passing within 1 LD of the Earth are included as well. Warning Times by Size This sub-section visual ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
List Of Asteroid Close Approaches To Earth In 2018
Below is the list of asteroid close approaches to Earth in 2018. Timeline of known close approaches less than one lunar distance from Earth A list of known near-Earth asteroid close approaches less than 1 lunar distance () from Earth in 2018.For a list of current Earth close approaches seNEO Earth Close Approaches/ref> For reference, the radius of Earth is approximately or 0.0166 lunar distances.Geosynchronous satellites have an orbit with semi-major axis length of or 0.110 lunar distances. Eight known asteroids ( 2018 BD, A106fgF, 2018 LA, A107j4q, , 2018 UA, , and ) are confirmed to have passed within this distance, and poorly-observed asteroids ZB0A262, , ZGBE54F, A1080DC , ZW87F01, and ZW900BE may have also passed within this distance. While most asteroids on this list are confirmed, well-observed unconfirmed objects with a 50% or greater chance of passing within 1 LD of the Earth are included as well. Warning Times by Size This sub-section visual ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Apollo Asteroids
The Apollo asteroids are a group of near-Earth asteroids named after 1862 Apollo, discovered by German astronomer Karl Reinmuth in the 1930s. They are Earth-crossing asteroids that have an orbital semi-major axis greater than that of the Earth (a > 1 AU) but perihelion distances less than the Earth's aphelion distance (q < 1.017 AU). , the number of known Apollo asteroids is 10,485, making the class the largest group of s (''cf''. the , Amor and Atira asteroids), [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Minor Planet Object Articles (unnumbered)
Minor may refer to: * Minor (law), a person under the age of certain legal activities. ** A person who has not reached the age of majority * Academic minor, a secondary field of study in undergraduate education Music theory *Minor chord ** Barbershop seventh chord or minor seventh chord *Minor interval *Minor key *Minor scale Mathematics * Minor (graph theory), the relation of one graph to another given certain conditions * Minor (linear algebra), the determinant of a certain submatrix People * Charles Minor (1835–1903), American college administrator * Charles A. Minor (21st-century), Liberian diplomat * Dan Minor (1909–1982), American jazz trombonist * Dave Minor (1922–1998), American basketball player * James T. Minor, US academic administrator and sociologist * Jerry Minor (born 1969), American actor, comedian and writer * Kyle Minor (born 1976), American writer * Mike Minor (actor) (born 1940), American actor * Mike Minor (baseball) (born 1987), American baseball pi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Near-Earth Objects In 2018
A near-Earth object (NEO) is any small Solar System body whose orbit brings it into proximity with Earth. By convention, a Solar System body is a NEO if its closest approach to the Sun ( perihelion) is less than 1.3 astronomical units (AU). If a NEO's orbit crosses the Earth's orbit, and the object is larger than across, it is considered a potentially hazardous object (PHO). Most known PHOs and NEOs are asteroids, but a small fraction are comets. There are over 30,503 known near-Earth asteroids (NEAs) and over a hundred known short-period near-Earth comets (NECs). A number of solar-orbiting meteoroids were large enough to be tracked in space before striking the Earth. It is now widely accepted that collisions in the past have had a significant role in shaping the geological and biological history of the Earth. Asteroids as small as in diameter can cause significant damage to the local environment and human populations. Larger asteroids penetrate the atmosphere to the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
