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28-422: These galaxies are in the process of colliding and merging with each other, as studies of their distributions of neutral and molecular hydrogen show, with the highest star-formation activity in the part where they overlap. However, the system is still in an early phase of interaction. In about 500 million years the galaxies will coalesce into a single elliptical galaxy. Four supernovae have been observed in

56-610: A bar structure , they are often reclassified as Magellanic spiral galaxies. The two galaxies are the following: The Magellanic clouds are visible to the unaided eye from the Southern Hemisphere , but cannot be observed from the most northern latitudes . An early possible mention of the Large Magellanic Cloud is in petroglyphs and rock drawings found in Chile . They may be the objects mentioned by

84-776: A galaxy merger . A giant galaxy interacting with its satellites is common. A satellite's gravity could attract one of the primary's spiral arms . Alternatively, the secondary satellite can dive into the primary galaxy, as in the Sagittarius Dwarf Elliptical Galaxy diving into the Milky Way . That can possibly trigger a small amount of star formation . Such orphaned clusters of stars were sometimes referred to as "blue blobs" before they were recognized as stars. Colliding galaxies are common during galaxy evolution . The extremely tenuous distribution of matter in galaxies means these are not collisions in

112-704: A first approach and we are witnessing the start of a galactic merger that may overlap with the Milky Way's expected merger with the Andromeda Galaxy (and perhaps the Triangulum Galaxy ) in the future. In 2019, astronomers discovered the young star cluster Price-Whelan 1 using Gaia data. The star cluster has a low metallicity and belongs to the leading arm of the Magellanic Clouds. The existence of this star cluster suggests that

140-545: A professional astronomer, in 964 CE, in his Book of Fixed Stars , mentioned the same quote, but with a different spelling. Under Argo Navis , he quoted that "unnamed others have claimed that beneath Canopus there are two stars known as the 'feet of Canopus', and beneath those there are bright white stars that are unseen in Iraq nor Najd , and that the inhabitants of Tihama call them al-Baqar [cows], and Ptolemy did not mention any of this so we [Al-Sufi] do not know if this

168-401: Is a stub . You can help Misplaced Pages by expanding it . Colliding and merging Interacting galaxies ( colliding galaxies ) are galaxies whose gravitational fields result in a disturbance of one another. An example of a minor interaction is a satellite galaxy disturbing the primary galaxy's spiral arms . An example of a major interaction is a galactic collision, which may lead to

196-499: Is about 70% larger than the diameter of the SMC (32,200 ly and 18,900 ly respectively). For comparison, the Milky Way is about 87,400 ly across. The total mass of these two galaxies is uncertain. Only a fraction of their gas seems to have coalesced into stars and they probably both have large dark matter halos. One recent estimate of the total mass of the LMC is about 1/10 that of

224-532: Is evidence that the SMC has been in orbit about the LMC for a very long time. The Magellanic system seems most similar to the distinct NGC 3109 system, which is on the edge of the Local Group. Astronomers have long assumed that the Magellanic Clouds have orbited the Milky Way at approximately their current distances, but evidence suggests that it is rare for them to come as close to the Milky Way as they are now. Observation and theoretical evidence suggest that

252-609: Is true or false." Both Ibn Qutaybah and Al-Sufi were probably quoting from the former's contemporary (and compatriot) and famed scientist Abu Hanifa Dinawari 's mostly lost work on Anwaa. Abu Hanifa was probably quoting earlier sources, which may be just travelers stories, and hence Al-Sufi's comments about their veracity. In Europe , the Clouds were reported by 16th century Italian authors Peter Martyr d'Anghiera and Andrea Corsali , both based on Portuguese voyages. Subsequently, they were reported by Antonio Pigafetta , who accompanied

280-488: The polymath Ibn Qutaybah (d. 889 CE), in his book on Al-Anwā̵’ (the stations of the Moon in pre-Islamic Arabian culture): وأسفل من سهيل قدما سهيل . وفى مجرى قدمى سهيل، من خلفهما كواكب زهر كبار، لا ترى بالعراق، يسميها أهل تهامة الأعبار And below Canopus , there are the feet of Canopus, and on their extension, behind them bright big stars, not seen in Iraq , the people of Tihama call them al-a‘bār . Later Al Sufi ,

308-507: The Butterfly Galaxies: SN 1990B ( type Ib , mag. 16), SN 2004cc (type Ic, mag. 17.5), SN 2020fqv ( type IIb , mag. 19), and SN 2023ijd (type II, mag. 16.8). The two galaxies were nicknamed "Siamese Twins" because they appear to be connected. On August 5, 2020, NASA announced that they would not use that nickname in an effort to avoid systemic discrimination in their terminology. This spiral galaxy article

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336-574: The Cepheid scales allowed Harlow Shapley to refine the measurement, and these were again revised in 1952 following further research. As of 2023 , some astronomers believe the Magellanic Clouds should be renamed, alleging that Magellan was a murderer and neither an astronomer nor the discoverer of the dwarf galaxies. The Large Magellanic Cloud and its neighbour and relative, the Small Magellanic Cloud , are conspicuous objects in

364-490: The Magellanic Clouds from South Africa, writing an 1847 report detailing 919 objects in the Large Magellanic Cloud and 244 objects in the Small Magellanic Cloud. In 1867 Cleveland Abbe suggested that they were separate satellites of the Milky Way. Distances were first estimated by Ejnar Hertzsprung in 1913 using 1912 measurements of Cepheid variables in the SMC by Henrietta Leavitt . Recalibration of

392-414: The Magellanic Clouds have both been greatly distorted by tidal interaction with the Milky Way as they travel close to it. The LMC maintains a very clear spiral structure in radio-telescope images of neutral hydrogen. Streams of neutral hydrogen connect them to the Milky Way and to each other, and both resemble disrupted barred spiral galaxies . Their gravity has affected the Milky Way as well, distorting

420-417: The Milky Way is taken as evidence for the theory. Galaxy harassment is a type of interaction between a low-luminosity galaxy and a brighter one that takes place within rich galaxy clusters , such as Virgo and Coma , where galaxies are moving at high relative speeds and suffering frequent encounters with other systems of the cluster due to the high galactic density. According to computer simulations ,

448-467: The Milky Way. That would make the LMC rather a large galaxy in the current observable universe. Since the sizes of relatively nearby galaxies are highly skewed, the average mass can be a misleading statistic. In terms of rank, the LMC appears to be the fourth most massive member of over 50 galaxies in the local group. Suggesting that the Magellanic cloud system is historically not a part of the Milky Way

476-561: The Virgo Cluster and finding structures, such as disks and spiral arms, which suggest they are former disc systems transformed by the above-mentioned interactions. The existence of similar structures in isolated early-type dwarf galaxies, such as LEDA 2108986 , has undermined this hypothesis. Astronomers have estimated the Milky Way Galaxy will collide with the Andromeda Galaxy in about 4.5 billion years. Some think

504-468: The colliding galaxies is much larger than the other, it will remain largely intact after the merger. The larger galaxy will look much the same, while the smaller galaxy will be stripped apart and become part of the larger galaxy. When galaxies pass through each other, unlike during mergers, they largely retain their material and shape after the pass. Galactic collisions are now frequently simulated on computers, which use realistic physics principles, including

532-629: The expedition of Ferdinand Magellan on its circumnavigation of the world in 1519–1522. However, naming the clouds after Magellan did not become widespread until much later. In Bayer's Uranometria they are designated as nubecula major and nubecula minor . In the 1756 star map of the French astronomer Lacaille , they are designated as le Grand Nuage and le Petit Nuage ("the Large Cloud" and "the Small Cloud"). John Herschel studied

560-429: The interactions convert the affected galaxy disks into disturbed barred spiral galaxies and produces starbursts followed by, if more encounters occur, loss of angular momentum and heating of their gas. The result would be the conversion of (late type) low-luminosity spiral galaxies into dwarf spheroidals and dwarf ellipticals . Evidence for the hypothesis had been claimed by studying early-type dwarf galaxies in

588-476: The leading arm of the Magellanic Clouds is 90,000 light-years away from the Milky Way—closer than previously thought. Astrophysicists D. S. Mathewson, V. L. Ford and N. Visvanathan proposed that the SMC may in fact be split in two, with a smaller section of this galaxy behind the main part of the SMC (as seen from Earth's perspective), and separated by about 30,000 light years. They suggest the reason for this

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616-517: The outer parts of the galactic disk . Aside from their different structure and lower mass, they differ from our galaxy in two major ways. They are gas-rich; a higher fraction of their mass is hydrogen and helium compared to the Milky Way. They are also more metal-poor than the Milky Way; the youngest stars in the LMC and SMC have a metallicity of 0.5 and 0.25 times solar, respectively. Both are noted for their nebulae and young stellar populations , but as in our own galaxy their stars range from

644-560: The process in which a large galaxy , through tidal gravitational interactions with a companion, merges with that companion. The most common result of the gravitational merger between two or more galaxies is a larger irregular galaxy , but elliptical galaxies may also result. It has been suggested that galactic cannibalism is currently occurring between the Milky Way and the Large and Small Magellanic Clouds . Streams of gravitationally-attracted hydrogen arcing from these dwarf galaxies to

672-484: The simulation of gravitational forces, gas dissipation phenomena, star formation, and feedback. Dynamical friction slows the relative motion of galaxy pairs, which may possibly merge at some point, according to the initial relative energy of the orbits. A library of simulated galaxy collisions can be found at the Paris Observatory website GALMER. Galactic cannibalism is a common phenomenon. It refers to

700-407: The southern hemisphere, looking like separated pieces of the Milky Way to the naked eye. Roughly 21 ° apart in the night sky, the true distance between them is roughly 75,000 light-years . Until the discovery of the Sagittarius Dwarf Elliptical Galaxy in 1994, they were the closest known galaxies to our own. The LMC lies about 160,000 light years away, while the SMC is around 200,000. The LMC

728-446: The traditional sense of the word, but rather gravitational interactions. Colliding may lead to merging if two galaxies collide and do not have enough momentum to continue traveling after the collision. As with other galaxy collisions , the merging of two galaxies may create a starburst region of new stars. In that case, they fall back into each other and eventually merge into one galaxy after many passes through each other. If one of

756-483: The two spiral galaxies will eventually merge to become an elliptical galaxy or perhaps a large disc galaxy . Magellanic Clouds The Magellanic Clouds ( Magellanic system or Nubeculae Magellani ) are two irregular dwarf galaxies in the southern celestial hemisphere . Orbiting the Milky Way galaxy , these satellite galaxies are members of the Local Group . Because both show signs of

784-536: The very young to the very old, indicating a long stellar formation history. The Large Magellanic Cloud was the host galaxy to a supernova ( SN 1987A ), the brightest observed in over four centuries. Measurements with the Hubble Space Telescope, announced in 2006, suggest the Magellanic Clouds may be moving too fast to be long term companions of the Milky Way . If they are in orbit, that orbit takes at least 4 billion years. They are possibly on

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