Mercury is the closest planet to the Sun and lacks any natural satellites. An undiscovered moon orbiting the planet was hypothesized to exist in the early 1970s, but it turned out to be misinterpreted data from the star 31 Crateris.[1] Observation of a moon of Mercury from Earth would be difficult because Mercury is relatively close to the Sun.[2] For example, Mercury was not observed in the infrared spectrum until 1995.[2]NASA's MESSENGER spacecraft, which orbited Mercury from 2011 to 2015, did not detect any moon.[3][4] Mercury's small Hill sphere limits the potential for a natural satellite to exist.[5]
A moon of Mercury was for a short time thought to exist. On March 27, 1974, two days before Mariner 10 made its flyby of Mercury, instruments began registering large amounts of ultraviolet radiation in the vicinity of Mercury that, according to one astronomer, "had no right to be there".[1] By the next day, the radiation had disappeared; it reappeared three days later, appearing to originate from an object that was, seemingly, detached from Mercury.[1] Some astronomers speculated that they had detected a star, but others argued that the object must be a moon, citing not only the two different directions from which the radiation had emanated but also the belief that such high-energy radiation could not penetrate very far through the interstellar medium.[1] Arguments in favor of a moon were strengthened when the object's speed was calculated to be 4 kilometres per second (2.5 mi/s), which matched the expected speed of a moon.[1]
A "moon" was detected moving away from Mercury in 1974, and was eventually identified as a background star, 31 Crateris. 31 Crateris is a spectroscopic binary with a period of 2.9 days, and this may have been the source of the ultraviolet radiation detected in 1974.[6] The 'moon of Mercury' misidentification in 1974 sparked an important discovery in astronomy: ultraviolet radiation is not as completely absorbed by the interstellar medium as was formerly thought.
MESSENGER missionedit
In an April Fools' Day joke in 2012, NASA announced that the MESSENGER spacecraft supposedly discovered a moon in orbit around Mercury, which they named jokingly Caduceus, in reference to the caduceus, the staff carried by the Roman god Mercury.[7] The MESSENGER mission used the spacecraft to search for moons of Mercury in 2011 and 2013, and confirmed that Mercury had none.[8]
^MESSENGER to Capture Images of Earth and Moon During Search for Satellites of Mercury (2013) 2013-07-25 at the Wayback Machine
April 11, 2024
hypothetical, moon, mercury, mercury, closest, planet, lacks, natural, satellites, undiscovered, moon, orbiting, planet, hypothesized, exist, early, 1970s, turned, misinterpreted, data, from, star, crateris, observation, moon, mercury, from, earth, would, diff. Mercury is the closest planet to the Sun and lacks any natural satellites An undiscovered moon orbiting the planet was hypothesized to exist in the early 1970s but it turned out to be misinterpreted data from the star 31 Crateris 1 Observation of a moon of Mercury from Earth would be difficult because Mercury is relatively close to the Sun 2 For example Mercury was not observed in the infrared spectrum until 1995 2 NASA s MESSENGER spacecraft which orbited Mercury from 2011 to 2015 did not detect any moon 3 4 Mercury s small Hill sphere limits the potential for a natural satellite to exist 5 Contents 1 Mariner 10 mission 1 1 31 Crateris 2 MESSENGER mission 3 See also 4 ReferencesMariner 10 mission editA moon of Mercury was for a short time thought to exist On March 27 1974 two days before Mariner 10 made its flyby of Mercury instruments began registering large amounts of ultraviolet radiation in the vicinity of Mercury that according to one astronomer had no right to be there 1 By the next day the radiation had disappeared it reappeared three days later appearing to originate from an object that was seemingly detached from Mercury 1 Some astronomers speculated that they had detected a star but others argued that the object must be a moon citing not only the two different directions from which the radiation had emanated but also the belief that such high energy radiation could not penetrate very far through the interstellar medium 1 Arguments in favor of a moon were strengthened when the object s speed was calculated to be 4 kilometres per second 2 5 mi s which matched the expected speed of a moon 1 31 Crateris edit nbsp 31 Crateris may be an eclipsing binary 6 Main article 31 Crateris A moon was detected moving away from Mercury in 1974 and was eventually identified as a background star 31 Crateris 31 Crateris is a spectroscopic binary with a period of 2 9 days and this may have been the source of the ultraviolet radiation detected in 1974 6 The moon of Mercury misidentification in 1974 sparked an important discovery in astronomy ultraviolet radiation is not as completely absorbed by the interstellar medium as was formerly thought MESSENGER mission editIn an April Fools Day joke in 2012 NASA announced that the MESSENGER spacecraft supposedly discovered a moon in orbit around Mercury which they named jokingly Caduceus in reference to the caduceus the staff carried by the Roman god Mercury 7 The MESSENGER mission used the spacecraft to search for moons of Mercury in 2011 and 2013 and confirmed that Mercury had none 8 See also editHypothetical astronomical object Claimed moons of EarthReferences edit a b c d e Mercury s Moon Hypothetical Planets Paul Schlyter 2009 a b Malcolm W Browne An Airborne Telescope Risks a Look At Mercury 1995 The New York Times MESSENGER Provides New Look at Mercury s Landscape Metallic Core and Polar Shadows Press release Johns Hopkins University March 21 2012 Archived from the original on May 13 2013 Retrieved 2012 03 22 A lot of moons or no moons at all NASA 5 November 2015 Q amp A Why doesn t Mercury have any moons Retrieved 2019 07 08 a b Stratford R L October 1980 31 Crateris reexamined The Observatory 100 168 Bibcode 1980Obs 100 168S HD 104337 near 11 58 17 515 19 22 50 18 NASA Featured Image Note inset seems to show 243 Ida MESSENGER to Capture Images of Earth and Moon During Search for Satellites of Mercury 2013 Archived 2013 07 25 at the Wayback Machine Retrieved from https en wikipedia org w index php title Hypothetical moon of Mercury amp oldid 1189399969, wikipedia, wiki, book, books, library,
