Misplaced Pages

#561438

38-784: The main targets of the experiment are the Magellanic Clouds and the Galactic Bulge , because of the large number of intervening stars that can be used for microlensing during a stellar transit . Most of the observations have been made at the Las Campanas Observatory in Chile . Cooperating institutions include Princeton University and the Carnegie Institution . The project is now in its fourth phase. The first phase, OGLE-I (1992–1995) used

76-692: A landform or the surrounding terrain, such as rivers and other geographic features. Some petroglyph maps, depicting trails, as well as containing symbols communicating the time and distances travelled along those trails, exist; other petroglyph maps act as astronomical markers. As well as holding geographic and astronomical importance, other petroglyphs may also have been a by-product of various rituals: sites in India, for example, have seen some petroglyphs identified as musical instruments or " rock gongs ". Some petroglyphs likely formed types of symbolic communication, such as types of proto-writing . Later glyphs from

114-491: A significant distance from stars around which they revolve despite there being other stars near them. In January 2022 in collaboration with Microlensing Observations in Astrophysics (MOA) they reported in a preprint the first rogue black hole . While there have been other candidates this is the most solid detection so far as their technique allowed to measure not only the amplification of light but also its deflection by

152-851: A temporary rock shelter were noticed adjacent to a Murugan temple which is in ruins on top of the Kothaiyurumbu hill. During recent years a large number of rock carvings has been identified in different parts of Iran. The vast majority depict the ibex . Rock drawings were found in December 2016 near Golpayegan , Iran , which may be the oldest drawings discovered, with one cluster possibly 40,000 years old. Accurate estimations were unavailable due to US sanctions. The oldest pictographs in Iran are seen in Yafteh cave in Lorestan that date back 40,000 and

190-771: Is harder to explain the common styles. This could be mere coincidence, an indication that certain groups of people migrated widely from some initial common area, or indication of a common origin. In 1853, George Tate presented a paper to the Berwick Naturalists' Club, at which a John Collingwood Bruce agreed that the carvings had "... a common origin, and indicate a symbolic meaning, representing some popular thought." In his cataloguing of Scottish rock art, Ronald Morris summarized 104 different theories on their interpretation. Other theories suggest that petroglyphs were carved by spiritual leaders, such as shamans , in an altered state of consciousness , perhaps induced by

228-535: 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 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,

266-645: The Nordic Bronze Age in Scandinavia seem to refer to some form of territorial boundary between tribes , in addition to holding possible religious meanings. Petroglyph styles have been recognised as having local or regional "dialects" from similar or neighboring peoples. Siberian inscriptions loosely resemble an early form of runes , although no direct relationship has been established. Petroglyphs from different continents show similarities. While people would be inspired by their direct surroundings, it

304-674: 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 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

342-641: The southern celestial hemisphere . Orbiting the Milky Way galaxy , these satellite galaxies are members of the Local Group . Because both show signs of 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

380-484: The 1.0-metre (3 ft 3 in) Swope telescope and a single-chip CCD sensor. For OGLE-II (1996–2000), a 1.3-metre (4 ft 3 in) telescope dedicated to the project (the Warsaw telescope) was constructed at Las Campanas Observatory. It was equipped with a single 2048×2048 pixel sensor with a field of view 0.237 degrees wide. OGLE-III (2001–2009) expanded the camera to a mosaic of eight 2048×4096 pixel CCDs, and

418-744: 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 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

SECTION 10

#1732779777562

456-502: The BH from the microlensing data. At least seventeen planets have so far been discovered by the OGLE project. Eight of the planets were discovered by the transit method and six by the gravitational microlensing method . Planets are shown in the order of discovery. Planets in multiple-planet systems are highlighted in yellow. The list below may not be complete. Notes: For events detected by

494-538: 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 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

532-540: 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 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

570-581: 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 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

608-594: The Large Magellanic Cloud is in petroglyphs and rock drawings found in Chile . They may be the objects mentioned by 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 ,

646-503: 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 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

684-431: The Milky Way and to each other, and both resemble disrupted barred spiral galaxies . Their gravity has affected the Milky Way as well, distorting 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

722-473: 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 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

760-463: 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 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

798-486: 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 is due to a past interaction with the LMC splitting the SMC, and that the two sections are still moving apart. They have dubbed this smaller remnant the Mini Magellanic Cloud. This hypothesis

SECTION 20

#1732779777562

836-676: The Witwatersrand studies present-day links between religion and rock art among the San people of the Kalahari Desert . Though the San people's artworks are predominantly paintings, the beliefs behind them can perhaps be used as a basis for understanding other types of rock art, including petroglyphs. To quote from the RARI website: Using knowledge of San beliefs, researchers have shown that

874-686: The art played a fundamental part in the religious lives of its painters. The art captured things from the San's world behind the rock-face: the other world inhabited by spirit creatures, to which dancers could travel in animal form, and where people of ecstasy could draw power and bring it back for healing, rain-making and capturing the game. Tunisia Eight sites in Hong Kong : Kethaiyurumpu, Tamil Nadu. Situated 28 km north west of Dindigal, Tamil Nadu nearby Idaiyakottai and six km south west of Oddanchartam has revealed several petroglyphs mostly represent abstract symbols on two rocks, which looks like

912-498: 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 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

950-464: The fourth and current phase, OGLE-IV, was started using a 32-chip mosaic CCD camera which fills the Warsaw telescope's 1.5° field of view. The main goal for this phase is to increase the number of planetary detections using microlensing, enabled by the new camera. Recently the OGLE team, in cooperation with scientists mostly from the US, New Zealand and Japan, proved that small, Earth-like planets can exist at

988-563: The gravitational microlensing method, year stands for OGLE season, BLG means that an event detected is in the Galactic B u LG e, and the following 3-digit number is an ordinal number of microlensing event in that season. For events detected by the transit method TR stands for TR ansit and the following 3-digit number is an ordinal number of transit event. Magellanic Clouds The Magellanic Clouds ( Magellanic system or Nubeculae Magellani ) are two irregular dwarf galaxies in

1026-587: The ground, are also quite different. Inuksuit are not petroglyphs, but human-made rock forms found in Arctic regions. Petroglyphs have been found in all parts of the globe except Antarctica , with highest concentrations in parts of Africa, Scandinavia and Siberia, many examples of petroglyphs found globally are dated to approximately the Neolithic and late Upper Paleolithic boundary (roughly 10,000 to 12,000 years ago). Around 7,000 to 9,000 years ago, following

1064-477: 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 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 ,

1102-459: The introduction of a number of precursors of writing systems , the existence and creation of petroglyphs began to suffer and tail off, with different forms of art, such as pictographs and ideograms , taking their place. However, petroglyphs continued to be created and remained somewhat common, with various cultures continuing to use them for differing lengths of time, including cultures who continued to create them until contact with Western culture

1140-467: The oldest petroglyph discovered belongs to Timareh dating back to 40,800 years ago. Iran provides demonstrations of script formation from pictogram, ideogram, linear (2300 BC) or proto Elamite, geometric old Elamite script, Pahlevi script, Arabic script (906 years ago), Kufi script, and Farsi script back to at least 250 years ago. More than 50000 petroglyphs have been discovered, extended over all Iran's states. The oldest reliably dated rock art in

1178-424: The people of Tihama call them al-a‘bār . Later Al Sufi , 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

Optical Gravitational Lensing Experiment - Misplaced Pages Continue

1216-483: The technique to refer to such images. Petroglyphs, estimated to be 20,000 years old are classified as protected monuments and have been added to the tentative list of UNESCO 's World Heritage Sites . Petroglyphs are found worldwide, and are often associated with prehistoric peoples. The word comes from the Greek prefix petro- , from πέτρα petra meaning " stone ", and γλύφω glýphō meaning "carve", and

1254-461: The use of natural hallucinogens . Many of the geometric patterns (known as form constants ) which recur in petroglyphs and cave paintings have been shown by David Lewis-Williams to be hardwired into the human brain. They frequently occur in visual disturbances and hallucinations brought on by drugs, migraine , and other stimuli. The Rock Art Research Institute (RARI) of the University of

1292-479: 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 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

1330-446: Was able to search for gravitational microlensing events and transiting planets in four fields: the Galactic Bulge , the constellation Carina , and toward both Magellanic Clouds . As a byproduct of the constant monitoring of hundreds of millions of stars, the largest catalogs of variable stars were constructed, and the first exoplanets discovered using the microlensing technique were detected. In 2010, following engineering work in 2009,

1368-466: Was confirmed in 2023. The part of the SMC which is closer to Earth lies 196,000 light-years (60 kiloparsecs) away, whereas the farther part lies 215,000 light-years (66 kiloparsecs) away. Petroglyph A petroglyph is an image created by removing part of a rock surface by incising, picking, carving, or abrading , as a form of rock art . Outside North America , scholars often use terms such as "carving", "engraving", or other descriptions of

1406-485: Was made in the 19th and 20th centuries. Many hypotheses exist as to the purpose of petroglyphs, depending on their location, age, and subject matter. Some petroglyph images most likely held a deep cultural and religious significance for the societies that created them. Many petroglyphs are thought to represent a type of symbolic or ritualistic language or communication style that remains not fully understood. Others, such as geocontourglyphs , more clearly depict or represent

1444-417: Was originally coined in French as pétroglyphe . In scholarly texts, a petroglyph is a rock engraving, whereas a petrograph (or pictograph ) is a rock painting. In common usage, the words are sometimes used interchangeably. Both types of image belong to the wider and more general category of rock art or parietal art . Petroforms , or patterns and shapes made by many large rocks and boulders over

#561438