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433 Eros is a near-Earth asteroid (NEA) discovered in 1898, and the first asteroid to be orbited by a probe (in 2000). It is an S-type asteroid approximately 34.4 11.2 11.2 km in size, the second-largest NEA after 1036 Ganymed, and belongs to the Amor group. Eros is a Mars-crosser asteroid, the first known to come within the orbit of Mars. Objects in such an orbit can remain there for only a few hundred million years before the orbit is perturbed by gravitational interactions. Dynamical integrations suggest that Eros may evolve into an Earth-crosser within as short an interval as 2 million years, and has a roughly 50% chance of doing so over a time scale of 108 109 years.[1] It is a potential Earth impactor,[1] believed to be larger than the impactor that created the Chicxulub Crater that led to the extinction of the dinosaurs.[2] The NEAR Shoemaker probe visited Eros twice, first with a 1998 flyby, and then by orbiting it in 2000 when it extensively photographed its surface. On February 12, 2001, at the end of its mission, it landed on the asteroid's surface using its maneuvering jets. The rarely used adjectival form of the name Eros is Erotian (). Eros is pronounced and the Greek is . It is named after the Greek god of love, Eros.
Physical characteristics  A composite image of the north polar region NEAR scientists have found that most of the larger rocks strewn across Eros were ejected from a single crater in a meteor collision approximately 1 billion years ago. This impact may also be responsible for the 40 percent of the Erotian surface that is devoid of craters smaller than 0.5 kilometers across. It was originally thought that the debris thrown up by the collision filled in the smaller craters. An analysis of crater densities over the surface indicates that the areas with lower crater density are within 9 kilometers of the impact point. Some of the lower density areas were found on the opposite side of the asteroid but still within 9 kilometers.[3] It is theorized that seismic shockwaves propagated through the asteroid, shaking smaller craters into rubble. Since Eros is irregularly shaped, parts of the surface antipodal to the point of impact can be within 9 kilometres of the impact point (measured in a straight line through the asteroid) even though some intervening parts of the surface are more than 9 kilometres away in straight-line distance. A suitable analogy would be the distance from the top centre of a bun to the bottom centre as compared to the distance from the top centre to a point on the bun's circumference: top-to-bottom is a longer distance than top-to-periphery when measured along the surface but shorter than it in direct straight-line terms.[3] History  Animation of the rotation of Eros.  View from one end of Eros across the gouge on its side towards the opposite end.(greyscale) As one of the larger near-Earth asteroids (NEAs), Eros has played a significant role in history. It was discovered on the same night (13 August 1898) by Gustav Witt in Berlin and Auguste Charlois at Nice.[4] Witt was taking a 2-hour exposure of Beta Aquarii to secure astrometric positions of asteroid 185 Eunike.[5] During the opposition of 1900 1901, a worldwide program was launched to make parallax measurements of the asteroid to determine the solar parallax (or distance to the sun), with the results published in 1910 by Arthur Hinks of Cambridge.[6] A similar program was then carried out, during a closer approach, in 1930 1931 by Harold Spencer Jones.[7] The value obtained by this program was considered definitive until 1968, when greater faith was placed in radar and dynamical parallax methods. Eros was one of the first asteroids to be visited by a spacecraft, and the first to be orbited and soft-landed on. NASA spacecraft NEAR Shoemaker entered orbit around Eros in 2000, and came to rest on its surface in 2001. Visibility from Earth On January 31, 2012, Eros passed the Earth at ,[8][9] about 70 times the distance to the Moon, with a visual magnitude of +8.1.[10] During rare oppositions, every 81 years, such as in 1975 and 2056, Eros can reach a magnitude of +7.0,[11] which is brighter than Neptune and brighter than any main-belt asteroid except 4 Vesta and, rarely, 2 Pallas and 7 Iris. Under this condition, the asteroid actually appears to stop, but unlike the normal condition for a body in heliocentric conjunction with the Earth, its retrograde motion is very small. For example, in January and February of 2137, it moves retrograde only 34 minutes in right ascension[12]. Its synodic period of over 846 earth days is among the largest of any body in the Solar System. Legal controversy In an experimental legal case, Eros was claimed as property by Gregory W. Nemitz of OrbDev. Nemitz argued that, according to the homestead principle, he had the right to claim ownership of any celestial body that he made use of; he claimed he had designated Eros a spacecraft parking facility and wished to charge NASA a parking and storage fee of twenty cents per year for NEAR Shoemaker. An expert in extraterrestrial real estate issues, Virgiliu Pop, responded by using the same novelty-deed registry Nemitz had used for Eros to claim ownership of the Sun, stating: Nemitz's case was dismissed and an appeal denied.[13] See also References and notes Further reading External links ast:433 Eros be:(433) bg:433 bs:433 Eros ca:(433) Eros cs:Eros (planetka) cy:433 Eros da:433 Eros (1898 DQ) de:(433) Eros el:433 eml:Eros (astronom ) es:(433) Eros eo:433 Eroso eu:433 Eros fa: fr:(433) ros gl:433 Eros ko:433 id:433 Eros it:433 Eros he: ( ) kn: ka: ( ) la:433 Eros lb:(433) Eros lt:433 Erotas hu:433 Eros nl:Eros (planeto de) ja: ( ) no:433 Eros nn:433 Eros pl:433 Eros pt:433 Eros ru:(433) simple:433 Eros sk:433 Eros sl:433 Eros sr:433 fi:433 Eros sv:433 Eros tl:433 Eros tr:Eros (astronomi) uk:433 vi:433 Eros zh:
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