|
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, based on the close approach database of the Center for Near-Earth Object Studies (CNEOS). 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. Five asteroids ( 2018 BD, , 2018 UA, , and ) are confirmed to have passed within this distance, and unconfirmed or confirmed but poorly observed asteroids A106fgF, A107j4q, ZB0A262, , ZGBE54F, A1080DC , ZW87F01, and ZW900BE may have also passed within this distance. The largest asteroid to pass within 1 LD of Earth in 2018 was with an estimated diameter of around 137 meters and an absolute magnitude of 22.5. The fastest asteroid to pass within 1 LD of Earth in 2018 was ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
2018 UA
2018 UA is a small Near-Earth object#Near-Earth asteroids, 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, it was probably the second closest non-impacting List of asteroid close approaches to Earth in 2018, 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 * * * Apollo asteroids, # 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] |
List Of Asteroid Close Approaches To Earth In 2016
Below is the list of asteroid close approaches to Earth in 2016. Timeline of known close approaches less than one Lunar distance from Earth in 2016 A list of known near-Earth asteroid close approaches less than 1 lunar distance () from Earth in 2016, based on the close approach database of the Center for Near-Earth Object Studies (CNEOS). For reference, the radius of Earth is approximately or 0.0166 Lunar distances.The orbit of geosynchronous satellites, however, is or 0.110 Lunar distances. This year, 6 (possibly 7) asteroids traveled nearer than this, most notably , which approached a mere 1.25 Earth radii (8000 km) from the surface. The CNEOS database of close approaches lists some close approaches a full orbit or more before the discovery of the object, derived by orbit calculation. The list below only includes close approaches that are evidenced by observations, thus the pre-discovery close approaches would only be included if the object was found by precovery, but ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
List Of Predicted Asteroid Impacts On Earth
This is a list of asteroids that have impacted Earth after discovery and orbit calculation that predicted the impact in advance, which are cataloged by the Center for Near-Earth Object Studies (CNEOS). , all of the asteroids with predicted impacts were under in size that were discovered just hours before impact, and burned up in the atmosphere as meteors A meteor, known colloquially as a shooting star, is a glowing streak of a small body (usually meteoroid) going through Earth's atmosphere, after being heated to incandescence by collisions with air molecules in the upper atmosphere, creating a .... References {{Planetary defense Near-Earth asteroids Planetary defense * ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Precovery
In astronomy, precovery (short for pre-discovery recovery) is the process of finding the image of a celestial 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 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Temporary Satellite
A temporary satellite is an object which has been captured by the gravitational field of a planet and thus has become the planet's natural satellite, but, unlike irregular moons of the larger outer planets of the Solar System, will eventually either leave its orbit around the planet or collide with the planet. The only observed examples are , a temporary satellite of Earth for twelve months from July 2006 to July 2007, and 2022 NX1. Some defunct space probes or rockets have also been observed on temporary satellite orbits. In astrophysics, a temporary satellite is any body that enters the Hill sphere of a planet at a sufficiently low velocity such that it becomes gravitationally bound to the planet for some period of time. Capture of asteroids The dynamics of the capture of asteroids by Earth was explored in simulations conducted on a supercomputer, with results published in 2012. Of 10 million virtual near-Earth asteroids, 18,000 have been temporarily captured. Earth has ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Apsis
An apsis (; ) is the farthest or nearest point in the orbit of a planetary body about its primary body. The line of apsides (also called apse line, or major axis of the orbit) is the line connecting the two extreme values. Apsides pertaining to orbits around different bodies have distinct names to differentiate themselves from other apsides. Apsides pertaining to geocentric orbits, orbits around the Earth, are at the farthest point called the ''apogee'', and at the nearest point the ''perigee'', like with orbits of satellites and the Moon around Earth. Apsides pertaining to orbits around the Sun are named ''aphelion'' for the farthest and ''perihelion'' for the nearest point in a heliocentric orbit. Earth's two apsides are the farthest point, ''aphelion'', and the nearest point, ''perihelion'', of its orbit around the host Sun. The terms ''aphelion'' and ''perihelion'' apply in the same way to the orbits of Jupiter and the other planets, the comets, and the asteroids of t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
2018 CB
is a very bright micro-asteroid, classified as a near-Earth object of the Apollo group, less than in diameter. It was first observed by astronomers of the Catalina Sky Survey at Mount Lemmon Observatory, Arizona, on 4 February 2018, during its sub-lunar close encounter with Earth. 2018 flyby On 9 February 2018, the asteroid passed about from Earth, traveling relative to Earth and briefly reaching apparent magnitude 13. It was observed by the Goldstone Observatory, which constrained its size to no more than 20 meters. During the flyby its period was changed from 1.48 years to 1.67 years. Flyby gallery File:2018CB skypath.png, Its path across the sky on February 9 was north to south (30 minute positions shown) File:2018CB earthflyby.png, Seen from space, it passes just outside geosynchronous orbit File:2018 CB Northolt Branch Observatory Feb7 video.gif, 20 minute timelapse, taken two days before closest approach. The asteroid can be seen near the center of the image, moving ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
2018 CC
is a micro-asteroid, classified as a near-Earth object of the Apollo group, approximately in diameter. Its official first observation was made by the Catalina Sky Survey at Mount Lemmon Observatory, Arizona, United States, on 4 February 2018. Two days later, the asteroid crossed the orbit of the Moon and made a very close approach to Earth. Orbit and classification belongs to the Apollo asteroids, which cross the orbit of Earth. Apollo's are the largest group of near-Earth objects with nearly 10 thousand known members. It orbits the Sun at a distance of 0.84–1.73 AU once every 18 months (531 days; semi-major axis of 1.28 AU). Its orbit has an eccentricity of 0.35 and an inclination of 8 ° with respect to the ecliptic. With an aphelion of 1.73 AU, it is also a Mars-crosser, as it crosses the orbit of the Red Planet at 1.66 AU. The body's observation arc begins with its first recorded observation by Pan-STARRS on 20 January 2018. Close approaches ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
2018 AH
2018 AH is a sub-kilometer asteroid, classified as near-Earth object of the Apollo group, approximately in diameter. It was first observed on 4 January 2018, by the Asteroid Terrestrial-impact Last Alert System (ATLAS) on Mauna Loa and quickly followed-up by many other surveys, with precovery observations found from Pan-STARRS and PTF from the day previous. It is the largest known asteroid to pass so close to Earth () since in 1971, and until in 2028, although it was only discovered two days after its closest approach on 2 January 2018, at 04:25 UTC. The Tunguska asteroid was likely of a similar size, if not slightly smaller. Before being recovered on 4 January 2022 11:49 UTC at an Earth distance of 9.8 million km, the asteroid only had an observation arc of 46 days and had not been observed since February 2018. Being a short arc object that had not been observed for years generated an uncertainty that is relatively large. Between 24–31 December 2021 it was only known to ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Moon
The Moon is Earth's only natural satellite. It Orbit of the Moon, orbits around Earth at Lunar distance, an average distance of (; about 30 times Earth diameter, Earth's diameter). The Moon rotation, rotates, with a rotation period (lunar day) that is synchronized to its orbital period (Lunar month#Synodic month, lunar month) of 29.5 Earth days. This is the product of Earth's gravitation having tidal forces, tidally pulled on the Moon until one part of it stopped rotating away from the near side of the Moon, near side, making always the same lunar surface face Earth. Conversley, the gravitational pull of the Moon, on Earth, is the main driver of Earth's tides. In geophysical definition of planet, geophysical terms, the Moon is a planetary-mass object or satellite planet. Its mass is 1.2% that of the Earth, and its diameter is , roughly one-quarter of Earth's (about as wide as the contiguous United States). Within the Solar System, it is the List of Solar System objects by ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Metre
The metre (or meter in US spelling; symbol: m) is the base unit of length in the International System of Units (SI). Since 2019, the metre has been defined as the length of the path travelled by light in vacuum during a time interval of of a second, where the second is defined by a hyperfine transition frequency of caesium. The metre was originally defined in 1791 by the French National Assembly as one ten-millionth of the distance from the equator to the North Pole along a great circle, so the Earth's polar circumference is approximately . In 1799, the metre was redefined in terms of a prototype metre bar. The bar used was changed in 1889, and in 1960 the metre was redefined in terms of a certain number of wavelengths of a certain emission line of krypton-86. The current definition was adopted in 1983 and modified slightly in 2002 to clarify that the metre is a measure of proper length. From 1983 until 2019, the metre was formally defined as the length of the pat ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
NASA
The National Aeronautics and Space Administration (NASA ) is an independent agencies of the United States government, independent agency of the federal government of the United States, US federal government responsible for the United States's civil list of government space agencies, space program, aeronautics research and outer space, space research. National Aeronautics and Space Act, Established in 1958, it succeeded the National Advisory Committee for Aeronautics (NACA) to give the American space development effort a distinct civilian orientation, emphasizing peaceful applications in space science. It has since led most of America's space exploration programs, including Project Mercury, Project Gemini, the 1968–1972 Apollo program missions, the Skylab space station, and the Space Shuttle. Currently, NASA supports the International Space Station (ISS) along with the Commercial Crew Program and oversees the development of the Orion (spacecraft), Orion spacecraft and the Sp ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
