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127-415: The VLT is capable of observing both visible and infrared wavelengths . Each individual telescope can detect objects that are roughly four billion times fainter than what can be seen with the naked eye . When all the telescopes are combined, the facility can achieve an angular resolution of approximately 0.002 arcsecond. In single telescope mode, the angular resolution is about 0.05 arcseconds. The VLT

254-563: A cold desert climate ( Köppen BWk ) with abundant sunshine and strong maritime influence. The marked aridity and water scarcity are regulated by the Humboldt Current , in addition to the high humidity and morning fog known as "Camanchaca". Furthermore, the Pacific anticyclone generates winds from the south and southwest. The average annual temperature is 16.8 °C (62.2 °F). The average daily low temperature in

381-644: A secret treaty of defensive alliance with Peru. This would be used as an argument 5 years later in Chile, when it unleashed the War of the Pacific . The secret alliance forbade Bolivia from signing a border treaty with Chile, without consulting with Peru . However, in 1874 Chile and Bolivia signed a border treaty, which replaced the previous treaty of 1866 . One of its points was not to impose new taxes on individuals, industries and Chilean capital for 25 years. For Bolivia,

508-467: A surface brightness high enough to be observed in the mid-infrared, and objects must be at several thousands of degrees Celsius for near-infrared observations using the VLTI. This includes most of the stars in the solar neighborhood and many extragalactic objects such as bright active galactic nuclei , but this sensitivity limit rules out interferometric observations of most solar-system objects. Although

635-404: A "pulse theory" and compared the spreading of light to that of waves in water in his 1665 work Micrographia ("Observation IX"). In 1672 Hooke suggested that light's vibrations could be perpendicular to the direction of propagation. Christiaan Huygens (1629–1695) worked out a mathematical wave theory of light in 1678 and published it in his Treatise on Light in 1690. He proposed that light

762-523: A 1.1 metre lightweight beryllium secondary mirror. A flat tertiary mirror diverts the light to one of two instruments at the f/15 Nasmyth foci on either side, with a system focal length of 120 m, or the tertiary tilts aside to allow light through the primary mirror central hole to a third instrument at the Cassegrain focus. This allows switching between any of the three instruments within 5 minutes, to match observing conditions. Additional mirrors can send

889-609: A better representation of how "bright" a light appears to be than raw intensity. They relate to raw power by a quantity called luminous efficacy and are used for purposes like determining how to best achieve sufficient illumination for various tasks in indoor and outdoor settings. The illumination measured by a photocell sensor does not necessarily correspond to what is perceived by the human eye and without filters which may be costly, photocells and charge-coupled devices (CCD) tend to respond to some infrared , ultraviolet or both. Light exerts physical pressure on objects in its path,

1016-556: A body could be so massive that light could not escape from it. In other words, it would become what is now called a black hole . Laplace withdrew his suggestion later, after a wave theory of light became firmly established as the model for light (as has been explained, neither a particle or wave theory is fully correct). A translation of Newton's essay on light appears in The large scale structure of space-time , by Stephen Hawking and George F. R. Ellis . The fact that light could be polarized

1143-730: A broken pump in a giant washing machine and resolving a rigging issue. The procedure is part of routine scheduled maintenance. The area surrounding the Very Large Telescope was featured in the 2008 film Quantum of Solace . The ESO Hotel , the Residencia, served as a backdrop for part of the James Bond movie. Producer Michael G. Wilson said: "The Residencia of Paranal Observatory caught the attention of our director, Marc Forster and production designer, Dennis Gassner, both for its exceptional design and its remote location in

1270-467: A force of about 3.3 piconewtons on the object being illuminated; thus, one could lift a U.S. penny with laser pointers, but doing so would require about 30 billion 1-mW laser pointers.   However, in nanometre -scale applications such as nanoelectromechanical systems (NEMS), the effect of light pressure is more significant and exploiting light pressure to drive NEMS mechanisms and to flip nanometre-scale physical switches in integrated circuits

1397-527: A large set of instruments permitting observations to be performed from the near-ultraviolet to the mid-infrared (i.e. a large fraction of the light wavelengths accessible from the surface of the Earth ), with the full range of techniques including high-resolution spectroscopy, multi-object spectroscopy , imaging, and high-resolution imaging. In particular, the VLT has several adaptive optics systems, which correct for

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1524-411: A lasting molecular change (a change in conformation) in the visual molecule retinal in the human retina, which change triggers the sensation of vision. There exist animals that are sensitive to various types of infrared, but not by means of quantum-absorption. Infrared sensing in snakes depends on a kind of natural thermal imaging , in which tiny packets of cellular water are raised in temperature by

1651-450: A medium faster than the speed of light in that medium can produce visible Cherenkov radiation . Certain chemicals produce visible radiation by chemoluminescence . In living things, this process is called bioluminescence . For example, fireflies produce light by this means and boats moving through water can disturb plankton which produce a glowing wake. Certain substances produce light when they are illuminated by more energetic radiation,

1778-424: A phenomenon which can be deduced by Maxwell's equations , but can be more easily explained by the particle nature of light: photons strike and transfer their momentum. Light pressure is equal to the power of the light beam divided by c , the speed of light.   Due to the magnitude of c , the effect of light pressure is negligible for everyday objects.   For example, a one-milliwatt laser pointer exerts

1905-419: A process known as fluorescence . Some substances emit light slowly after excitation by more energetic radiation. This is known as phosphorescence . Phosphorescent materials can also be excited by bombarding them with subatomic particles. Cathodoluminescence is one example. This mechanism is used in cathode-ray tube television sets and computer monitors . Certain other mechanisms can produce light: When

2032-410: A source. One of Newton's arguments against the wave nature of light was that waves were known to bend around obstacles, while light travelled only in straight lines. He did, however, explain the phenomenon of the diffraction of light (which had been observed by Francesco Grimaldi ) by allowing that a light particle could create a localised wave in the aether . Newton's theory could be used to predict

2159-414: A surface between one transparent material and another. It is described by Snell's Law : where θ 1 is the angle between the ray and the surface normal in the first medium, θ 2 is the angle between the ray and the surface normal in the second medium and n 1 and n 2 are the indices of refraction , n = 1 in a vacuum and n > 1 in a transparent substance . When a beam of light crosses

2286-557: A value of 298 000 000  m/s in 1862. Albert A. Michelson conducted experiments on the speed of light from 1877 until his death in 1931. He refined Foucault's methods in 1926 using improved rotating mirrors to measure the time it took light to make a round trip from Mount Wilson to Mount San Antonio in California. The precise measurements yielded a speed of 299 796 000  m/s . The effective velocity of light in various transparent substances containing ordinary matter ,

2413-466: Is a port city in northern Chile , about 1,100 kilometres (700 mi) north of Santiago . It is the capital of Antofagasta Province and Antofagasta Region . According to the 2015 census, the city has a population of 402,669. Once claimed by Bolivia following the Spanish American wars of independence , Antofagasta was captured by Chile on February 14, 1879, triggering the War of

2540-530: Is also affected by the colour spectrum of light, a process known as photomorphogenesis . The speed of light in vacuum is defined to be exactly 299 792 458  m/s (approximately 186,282 miles per second). The fixed value of the speed of light in SI units results from the fact that the metre is now defined in terms of the speed of light. All forms of electromagnetic radiation move at exactly this same speed in vacuum. Different physicists have attempted to measure

2667-459: Is an active area of research. At larger scales, light pressure can cause asteroids to spin faster, acting on their irregular shapes as on the vanes of a windmill .   The possibility of making solar sails that would accelerate spaceships in space is also under investigation. Although the motion of the Crookes radiometer was originally attributed to light pressure, this interpretation

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2794-399: Is by far the most important mining activity for Antofagasta, fueling a steady growth in the areas of construction, retail, hotel accommodations, population growth and skyline development until the end of the 2000s commodities boom in 2013. Since the 2010s Antofagasta is also a service hub for lithium mining. In 2012, Antofagasta has the highest GDP per capita of Chile, US$ 37,000 and

2921-429: Is caused by the surface roughness of the reflecting surfaces, and internal scatterance is caused by the difference of refractive index between the particles and medium inside the object. Like transparent objects, translucent objects allow light to transmit through, but translucent objects also scatter certain wavelength of light via internal scatterance. Refraction is the bending of light rays when passing through

3048-466: Is directly elected every four years. As of 2021, the mayor is Jonathan Velásquez. The communal council has the following members: Within the electoral divisions of Chile , Antofagasta is represented in the Chamber of Deputies by Marcela Hernando ( PRSD ) and Paulina Nuñez ( RN ) as part of the 4th electoral district, together with Mejillones , Sierra Gorda and Taltal . The commune is represented in

3175-471: Is done using 1.8 meter Auxiliary Telescopes (ATs), which are dedicated to full-time interferometric measurements. The first observations using a pair of ATs were conducted in February 2005, and all the four ATs have now been commissioned. For interferometric observations on the brightest objects, there is little benefit in using 8 meter telescopes rather than 1.8 meter telescopes. The first two instruments at

3302-462: Is incorrect; the characteristic Crookes rotation is the result of a partial vacuum. This should not be confused with the Nichols radiometer , in which the (slight) motion caused by torque (though not enough for full rotation against friction) is directly caused by light pressure. As a consequence of light pressure, Einstein in 1909 predicted the existence of "radiation friction" which would oppose

3429-447: Is introduced, the limiting magnitude of the VLTI is expected to improve by a factor of almost 1000, reaching a magnitude of about 14. This is similar to what is expected for other fringe tracking interferometers. In spectroscopic mode, the VLTI can currently reach a magnitude of 1.5. The VLTI can work in a fully integrated way, so that interferometric observations are actually quite simple to prepare and execute. The VLTI has become worldwide

3556-654: Is less than in vacuum. For example, the speed of light in water is about 3/4 of that in vacuum. Two independent teams of physicists were said to bring light to a "complete standstill" by passing it through a Bose–Einstein condensate of the element rubidium , one team at Harvard University and the Rowland Institute for Science in Cambridge, Massachusetts and the other at the Harvard–Smithsonian Center for Astrophysics , also in Cambridge. However,

3683-401: Is mainly based on copper mining and nonmetallic minerals such as nitrate and iodine . There are refinery furnaces for the copper industry. Cement and lime are mined to aid copper refining. The area also has iron ore deposits, for steel. The second industrial area is located in the north of the city, where they have installed multiple operating centers of different companies, mainly along

3810-409: Is one of the fundamental constants of nature. Like all types of electromagnetic radiation, visible light propagates by massless elementary particles called photons that represents the quanta of electromagnetic field, and can be analyzed as both waves and particles . The study of light, known as optics , is an important research area in modern physics . The main source of natural light on Earth

3937-559: Is one of the most productive facilities for astronomy, second only to the Hubble Space Telescope in terms of the number of scientific papers produced from facilities operating at visible wavelengths. Some of the pioneering observations made using the VLT include the first direct image of an exoplanet , the tracking of stars orbiting around the supermassive black hole at the centre of the Milky Way , and observations of

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4064-514: Is public, University of Antofagasta , and other private, Catholic University of the North . Several private autonomous universities have been open since 2002. Previously, the now-defunct "University José Santos Ossa" was the only private autonomous university in Antofagasta. Although the public schools are distributed almost uniformly throughout the city, the private schools operate mainly in

4191-449: Is regarded as the start of modern physical optics. Pierre Gassendi (1592–1655), an atomist, proposed a particle theory of light which was published posthumously in the 1660s. Isaac Newton studied Gassendi's work at an early age and preferred his view to Descartes's theory of the plenum . He stated in his Hypothesis of Light of 1675 that light was composed of corpuscles (particles of matter) which were emitted in all directions from

4318-465: Is subject to a climate of extreme aridity, and therefore generates a low average annual rainfall of 3.4 mm (0.13 in) (1970–2000), and the Town of Antofagasta itself receives an annual average of less than 0.1 mm (0.004 in) of rainfall per year, earning it the record as the world's driest town. However, the sporadic occurrence of heavy rainfall, together with the geomorphologic situation of

4445-825: Is the Sun . Historically, another important source of light for humans has been fire , from ancient campfires to modern kerosene lamps . With the development of electric lights and power systems , electric lighting has effectively replaced firelight. Generally, electromagnetic radiation (EMR) is classified by wavelength into radio waves , microwaves , infrared , the visible spectrum that we perceive as light, ultraviolet , X-rays and gamma rays . The designation " radiation " excludes static electric , magnetic and near fields . The behavior of EMR depends on its wavelength. Higher frequencies have shorter wavelengths and lower frequencies have longer wavelengths. When EMR interacts with single atoms and molecules, its behavior depends on

4572-571: Is the gravitational redshift . In fact, the observation has been conducted for over 26 years with the SINFONI and NACO adaptive optics instruments in the VLT while the new approach in 2018 also used the beam-combiner instrument GRAVITY. The Galactic Centre team at the Max Planck Institute for Extraterrestrial Physics (MPE) used these observations to reveal these effects for the first time. Other discoveries with VLT's signature include

4699-567: Is the capital to write about the implications of these names. It drew many entries dealing with the cultural heritage of ESO's host country. The winning essay was submitted by 17-year-old Jorssy Albanez Castilla from Chuquicamata near the city of Calama . She received the prize, an amateur telescope, during the inauguration of the Paranal site. Unit Telescopes 1–4 are since known as Antu (Sun), Kueyen (Moon), Melipal ( Southern Cross ), and Yepun (Evening Star), respectively. Originally there

4826-559: The Calidris and mammals like the culpeo fox , inhabit or visit the wetlands. Some of these wetlands are threatened by garbage, street dogs , extraction of water, establishments of shacks ( Spanish : ruco ) and the diversion of water courses. As of January 2024 the municipality of Antofagasta plans to declare the wetlands official urban wetlands in accordance with the Urban Wetlands Law . The town of Antofagasta has

4953-504: The Académie des Sciences in 1817. Siméon Denis Poisson added to Fresnel's mathematical work to produce a convincing argument in favor of the wave theory, helping to overturn Newton's corpuscular theory. By the year 1821, Fresnel was able to show via mathematical methods that polarization could be explained by the wave theory of light if and only if light was entirely transverse, with no longitudinal vibration whatsoever. The weakness of

5080-625: The GRAVITY instrument on their Very Large Telescope Interferometer (VLTI), announced the first direct detection of an exoplanet , HR 8799 e , using optical interferometry . One of the large mirrors of the telescopes was the subject of an episode of the National Geographic Channel 's reality series World's Toughest Fixes , where a crew of engineers removed and transported the mirror to be cleaned and re-coated with aluminium . The job required battling strong winds, fixing

5207-568: The Senate by Pedro Araya ( Progressive Convergence , 2014–2022) and Alejandro Guillier ( Progressive Convergence , 2014–2022) as part of the 2nd senatorial constituency (Antofagasta Region). The township has three local police courts. In addition, the Municipality of Antofagasta has a number of municipal headquarters, which are entities created to meet and control certain community needs a more specific way. Antofagasta's economic development

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5334-607: The University of Chile . On 18 June 1991, a mudslide devastated much of the city , undermining land, damaged 2,464 houses and destroyed 493 buildings. Material damage was estimated at $ 70,000,000. The disaster left 92 dead, 16 missing and about 20,000 homeless. On 30 July 1995, the city was hit by an earthquake measuring 7.3 on the Richter Scale , with an intensity VII to VIII on the Mercalli Scale . The city

5461-428: The aurora borealis offer many clues as to the nature of light. A transparent object allows light to transmit or pass through. Conversely, an opaque object does not allow light to transmit through and instead reflecting or absorbing the light it receives. Most objects do not reflect or transmit light specularly and to some degree scatters the incoming light, which is called glossiness . Surface scatterance

5588-573: The infrared (with longer wavelengths and lower frequencies) and the ultraviolet (with shorter wavelengths and higher frequencies), called collectively optical radiation . In physics , the term "light" may refer more broadly to electromagnetic radiation of any wavelength, whether visible or not. In this sense, gamma rays , X-rays , microwaves and radio waves are also light. The primary properties of light are intensity , propagation direction, frequency or wavelength spectrum , and polarization . Its speed in vacuum , 299 792 458  m/s ,

5715-431: The reflection of light, but could only explain refraction by incorrectly assuming that light accelerated upon entering a denser medium because the gravitational pull was greater. Newton published the final version of his theory in his Opticks of 1704. His reputation helped the particle theory of light to hold sway during the eighteenth century. The particle theory of light led Pierre-Simon Laplace to argue that

5842-624: The refraction of light in his book Optics . In ancient India , the Hindu schools of Samkhya and Vaisheshika , from around the early centuries AD developed theories on light. According to the Samkhya school, light is one of the five fundamental "subtle" elements ( tanmatra ) out of which emerge the gross elements. The atomicity of these elements is not specifically mentioned and it appears that they were actually taken to be continuous. The Vishnu Purana refers to sunlight as "the seven rays of

5969-441: The "Hoya La Chimba", "Hoya Caracoles", "Hoya La Cadena", "Hoya La Negra" and "Hoya El Way". These watersheds and their streams ( Quebrada ), such as "Quebrada sin nombre", "Quebrada Baquedano", "Quebrada El Toro", "Quebrada El Carrizo" and "Quebrada Jardines del Sur", which helped cause the flood of 1991. The coastal edge of Antofagasta is rocky and steep, so there are no natural beaches, the majority being artificial. Just north of

6096-505: The "Pedro Aguirre Cerda Avenue." Since the 2010s Antofagasta is a hub for lithium mining. Chile has the largest reserves of lithium worldwide and was the second largest producer in 2024, after Australia, and it is shipped from Antofagasta. Trade is concentrated mainly in the center of Antofagasta, around the Plaza Colón , where within the last 2 decades several national retail chains were in place. Moreover, in different parts of

6223-594: The 3rd place for Human Development Index just after Metropolitana de Santiago Region and Magallanes and Antártica Chilena Region . The territory of Antofagasta was included in maps of the Captaincy General of Chile in the 18th century, depending from the city of Copiapó . The territory was disputed between Chile and Bolivia until the signing of the Boundary Treaty of 1866 . On 18 September 1866, José Santos Ossa and Francisco Puelma achieved

6350-546: The 54% of copper at the national level, business events are held in Antofagasta. Events are held annually with the assistance of several mining countries of the world, and one of the most important is Exponor organized by the Asociación de Industriales Antofagasta, guild formed by the major copper producers in the region. Exponor is a show that promotes the gestation of chains, new business and exchanging knowledge and experiences among entrepreneurs from different countries of

6477-577: The Atacama desert. It is a true oasis and the perfect hide out for Dominic Greene, our villain, whom 007 is tracking in our new James Bond film." Visible light Light , visible light , or visible radiation is electromagnetic radiation that can be perceived by the human eye . Visible light spans the visible spectrum and is usually defined as having wavelengths in the range of 400–700 nanometres (nm), corresponding to frequencies of 750–420 terahertz . The visible band sits adjacent to

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6604-700: The British community ( La Colonia Britanica ) erected a clock tower, replicating Big Ben , in Plaza Colón to celebrate the republic's centenary. In 1956, the Universidad del Norte (now the Catholic University of the North ) was founded, due to support from the Catholic University of Valparaíso . On 9 October, of the same year began the negotiations for the creation of the "Centro Universitario Zona Norte" (University Center North Zone), part of

6731-688: The Chilean occupation of Antofagasta, on 14 February 1879. According to the Chilean version of events, the tax of 10 cents violated the treaty of 1874 since according to this, new taxes should not have been imposed on Chilean companies operating in Bolivia. At the breaking of the boundary treaty by Bolivia, and the cancellation of the contract of the CSFA, Chile seized Antofagasta, then in Bolivian territory, whose sovereignty had been ratified before 1866. After

6858-414: The Pacific (1879–83). Chilean sovereignty was officially recognised by Bolivia under the terms of the 1904 Treaty of Peace and Friendship . The city of Antofagasta is closely linked to mining activity, being a port and the chief service hub for one of Chile's major mining areas. While silver and saltpeter mining have been historically important for Antofagasta, since the mid-19th century copper mining

6985-580: The UTs are 8.2 meters in diameter but, in practice, the pupil of the telescopes is defined by their secondary mirrors, effectively reducing the usable diameter to 8.0 meters at the Nasmyth focus and 8.1 meters at the Cassegrain focus . The 8.2 m-diameter telescopes are housed in compact, thermally controlled buildings, which rotate synchronously with the telescopes. This design minimises any adverse effects on

7112-571: The UTs started operating in May 1998 and was offered to the astronomical community on 1 April 1999. The other telescopes became operational in 1999 and 2000, enabling multi-telescope VLT capability. Four 1.8-metre Auxiliary Telescopes (ATs) have been added to the VLTI to make it available when the UTs are being used for other projects. These ATs were installed and became operational between 2004 and 2007. The VLT's 8.2-meter telescopes were originally designed to operate in three modes: The UTs are equipped with

7239-418: The VLTI lab, along with ESPRESSO fed via fibre-optics (not interferometric). From 2014 to 2020 it underwent a major upgrade to CRIRES+ to provide ten times larger simultaneous wavelength coverage. A new detector focal plane array of three Hawaii 2RG detectors with a 5.3 μm cut-off wavelength replaced the existing detectors, a new spectropolarimetric unit is added, and the calibration system is enhanced. One of

7366-495: The VLTI were VINCI (a test instrument used to set up the system, now decommissioned) and MIDI, which only allow two telescopes to be used at any one time. With the installation of the three-telescope AMBER closure-phase instrument in 2005, the first imaging observations from the VLTI are expected soon. Deployment of the Phase Referenced Imaging and Microarcsecond Astrometry (PRIMA) instrument started 2008 with

7493-440: The afterglow of the furthest known gamma-ray burst . The VLT consists of an arrangement of four large (8.2 metre diameter) telescopes (called Unit Telescopes or UTs) with optical elements that can combine them into an astronomical interferometer (VLTI), which is used to resolve small objects. The interferometer also includes a set of four 1.8 meter diameter movable telescopes dedicated to interferometric observations. The first of

7620-570: The aim to allow phase-referenced measurements in either an astrometric two-beam mode or as a fringe-tracker successor to VINCI, operated concurrent with one of the other instruments. After falling drastically behind schedule and failing to meet some specifications, in December 2004 the VLT Interferometer became the target of a second ESO "recovery plan". This involves additional effort concentrated on improvements to fringe tracking and

7747-456: The amount of energy per quantum it carries. EMR in the visible light region consists of quanta (called photons ) that are at the lower end of the energies that are capable of causing electronic excitation within molecules, which leads to changes in the bonding or chemistry of the molecule. At the lower end of the visible light spectrum, EMR becomes invisible to humans (infrared) because its photons no longer have enough individual energy to cause

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7874-676: The angular diameters of four red dwarfs including Proxima Centauri . During this operation it achieved an angular resolution of ±0.08 milli-arc-seconds (0.388 nano-radians). This is comparable to the resolution achieved using other arrays such as the Navy Prototype Optical Interferometer and the CHARA array . Unlike many earlier optical and infrared interferometers, the Astronomical Multi-Beam Recombiner (AMBER) instrument on VLTI

8001-470: The apparent size of images. Magnifying glasses , spectacles , contact lenses , microscopes and refracting telescopes are all examples of this manipulation. There are many sources of light. A body at a given temperature emits a characteristic spectrum of black-body radiation . A simple thermal source is sunlight , the radiation emitted by the chromosphere of the Sun at around 6,000  K (5,730  °C ; 10,340  °F ). Solar radiation peaks in

8128-487: The award of the concession of nitrate lands, following a request taken to the Bolivian government . The exploring of the Chilean miners found rich deposits of saltpeter ( nitratine ) in the field of Salar del Carmen , to the east of the present Antofagasta. Agreed to form the " Sociedad Exploradora del Desierto de Atacama " (Explorer Society of Atacama Desert). After the formation of the company, began to fill with what

8255-605: The beam from the eye travels infinitely fast this is not a problem. In 55 BC, Lucretius , a Roman who carried on the ideas of earlier Greek atomists , wrote that "The light & heat of the sun; these are composed of minute atoms which, when they are shoved off, lose no time in shooting right across the interspace of air in the direction imparted by the shove." (from On the nature of the Universe ). Despite being similar to later particle theories, Lucretius's views were not generally accepted. Ptolemy (c. second century) wrote about

8382-513: The body of "Municipal Agents", composed of two Germans, one Englishman and six Chileans. On 27 November 1873, the "Compañía de Salitres y Ferrocarril de Antofagasta" (CSFA), a Chilean mining company, signed a contract with the government of Bolivia, in which taxes were removed from mineral exploitation for 15 years. This contract was not ratified by the Congress of Bolivia, which was then analyzed negotiations with Chile. In 1873, Bolivia signed

8509-452: The boundary between a vacuum and another medium, or between two different media, the wavelength of the light changes, but the frequency remains constant. If the beam of light is not orthogonal (or rather normal) to the boundary, the change in wavelength results in a change in the direction of the beam. This change of direction is known as refraction . The refractive quality of lenses is frequently used to manipulate light in order to change

8636-408: The city large supermarket chains like " Líder ", "Tottus", "Unimarc", "Santa Isabel" and "Jumbo" are set up. In 2006, the national chain "Mall Plaza" was built in the coastal area and the "Casino Enjoy Antofagasta" was built in the south of the city. Because of the important administrative position of Antofagasta in the region, the historical relationship with the mining sector, and the production of

8763-409: The city, make it susceptible to be affected by mud flows and landslides. Between 1916 and 1999, the city was affected by floods or landslides on seven occasions: 1925, 1930, twice in 1940, 1982, 1987 and 1991 , of which the most important episodes in 1940 and 1991. There are about fifteen streams that have watersheds with accumulation of sand and gravel. Within the broader watershed ( hoya ) are

8890-486: The city, natural beaches extend to the areas of "La Portada", "Las Losetas" and "La Rinconada". Within the water resources of the commune, there are different dry lakes (salar), among which include the Salar de Pajonales, Salar Mar Muerto, Salar Punta Negra and the Salar de Navidad. As a commune , Antofagasta is a third-level administrative division of Chile administered by a municipal council , headed by an alcalde who

9017-500: The commune, 295,792 (99.6%) lived in urban areas and 1,113 (0.4%) in rural areas. The population grew by 30.0% (68,497 persons) between the 1992 and 2002 censuses. A 2009 population projection by the National Institute of Statistics of Chile estimated the city has an estimated population of 360,473 inhabitants. The city has several public and private educational universities. Two major traditional universities , one that

9144-592: The concept of light is intended to include very-high-energy photons (gamma rays), additional generation mechanisms include: Light is measured with two main alternative sets of units: radiometry consists of measurements of light power at all wavelengths, while photometry measures light with wavelength weighted with respect to a standardized model of human brightness perception. Photometry is useful, for example, to quantify Illumination (lighting) intended for human use. The photometry units are different from most systems of physical units in that they take into account how

9271-407: The contract of 1873 between the government and CSFA was not yet in force, because, according to the Bolivian constitution, all contracts with the Bolivian government had to be approved by the congress. According to the Bolivian version of events, the contract with the saltpeter company was incomplete so the congress, to approve the contract, decided to enforce a tax of 10 cents, which did not violate

9398-541: The detection of carbon monoxide molecules in a galaxy located almost 11 billion light-years away for the first time, a feat that had remained elusive for 25 years. This has allowed astronomers to obtain the most precise measurement of the cosmic temperature at such a remote epoch. Another important study was that of the violent flares from the supermassive black hole at the centre of the Milky Way. The VLT and APEX teamed up to reveal material being stretched out as it orbits in

9525-451: The diameter of Earth's orbit. However, its size was not known at that time. If Rømer had known the diameter of the Earth's orbit, he would have calculated a speed of 227 000 000  m/s . Another more accurate measurement of the speed of light was performed in Europe by Hippolyte Fizeau in 1849. Fizeau directed a beam of light at a mirror several kilometers away. A rotating cog wheel

9652-412: The effects of atmospheric turbulence, providing images almost as sharp as if the telescope were in space. In the near-infrared, the adaptive optics images of the VLT are up to three times sharper than those of the Hubble Space Telescope , and the spectroscopic resolution is many times better than Hubble. The VLTs are noted for their high level of observing efficiency and automation. The primary mirrors of

9779-464: The enclosure and transporter are mechanically isolated from the telescope, to ensure that no vibrations compromise the data collected. The transporter section runs on tracks, so the ATs can be moved to 30 different observing locations. As the VLTI acts rather like a single telescope as large as the group of telescopes combined, changing the positions of the ATs means that the VLTI can be adjusted according to

9906-406: The exoplanetary atmosphere . This important wavelength region is covered by CRIRES+, which will additionally allow tracking multiple absorption lines simultaneously. In its interferometric operating mode, the light from the telescopes is reflected off mirrors and directed through tunnels to a central beam combining laboratory. In the year 2001, during commissioning, the VLTI successfully measured

10033-497: The eye. Another supporter of the wave theory was Leonhard Euler . He argued in Nova theoria lucis et colorum (1746) that diffraction could more easily be explained by a wave theory. In 1816 André-Marie Ampère gave Augustin-Jean Fresnel an idea that the polarization of light can be explained by the wave theory if light were a transverse wave . Later, Fresnel independently worked out his own wave theory of light and presented it to

10160-434: The eyes and rays from a source such as the sun. In about 300 BC, Euclid wrote Optica , in which he studied the properties of light. Euclid postulated that light travelled in straight lines and he described the laws of reflection and studied them mathematically. He questioned that sight is the result of a beam from the eye, for he asks how one sees the stars immediately, if one closes one's eyes, then opens them at night. If

10287-437: The fifth century BC, Empedocles postulated that everything was composed of four elements ; fire, air, earth and water. He believed that goddess Aphrodite made the human eye out of the four elements and that she lit the fire in the eye which shone out from the eye making sight possible. If this were true, then one could see during the night just as well as during the day, so Empedocles postulated an interaction between rays from

10414-427: The first extrasolar planet so imaged, tracking individual stars moving around the supermassive black hole at the centre of the Milky Way, and observing the afterglow of the furthest known gamma-ray burst . In 2018, the VLT helped to perform the first successful test of Albert Einstein 's General Relativity on the motion of a star passing through the extreme gravitational field near the supermassive black hole, that

10541-464: The first general user optical/infrared interferometric facility offered with this kind of service to the astronomical community. Because of the many mirrors involved in the optical train, about 95% of the light is lost before reaching the instruments at a wavelength of 1 μm, 90% at 2 μm and 75% at 10 μm. This refers to reflection off 32 surfaces including the Coudé train, the star separator,

10668-430: The first time using the VLT. The planet, which is known as GJ 1214b , was studied as it passed in front of its parent star and some of the starlight passed through the planet's atmosphere. In all, of the top 10 discoveries done at ESO's observatories, seven made use of the VLT. Each Unit Telescope is a Ritchey-Chretien Cassegrain telescope with a 22-tonne 8.2 metre Zerodur primary mirror of 14.4 m focal length, and

10795-425: The force of pressure acting on the back. Hence, as the resultant of the two forces, there remains a force that counteracts the motion of the plate and that increases with the velocity of the plate. We will call this resultant 'radiation friction' in brief." Usually light momentum is aligned with its direction of motion. However, for example in evanescent waves momentum is transverse to direction of propagation. In

10922-535: The four VLT Unit Telescopes, to replace the original technical designations of UT1 to UT4. In March 1999, at the time of the Paranal inauguration, four meaningful names of objects in the sky in the Mapuche language were chosen. This indigenous people lives mostly south of Santiago de Chile. An essay contest was arranged in this connection among schoolchildren of the Chilean II Region of which Antofagasta

11049-518: The four smaller 1.8-metre ATs are available and dedicated to interferometry to allow the VLTI to operate every night. The top part of each AT is a round enclosure, made from two sets of three segments, which open and close. Its job is to protect the delicate 1.8-metre telescope from the desert conditions. The enclosure is supported by the boxy transporter section, which also contains electronics cabinets, liquid cooling systems, air-conditioning units, power supplies, and more. During astronomical observations

11176-421: The human eye responds to light. The cone cells in the human eye are of three types which respond differently across the visible spectrum and the cumulative response peaks at a wavelength of around 555 nm. Therefore, two sources of light which produce the same intensity (W/m ) of visible light do not necessarily appear equally bright. The photometry units are designed to take this into account and therefore are

11303-456: The individual telescopes. The light beams are combined in the VLTI using a complex system of mirrors in tunnels where the light paths must be kept equal within differences of less than 1 μm over a light path of a hundred metres. With this kind of precision, the VLTI can reconstruct images with an angular resolution of milliarcseconds. It had long been ESO's intention to provide "real" names to

11430-418: The infrared and only a fraction in the visible spectrum. The peak of the black-body spectrum is in the deep infrared, at about 10 micrometre wavelength, for relatively cool objects like human beings. As the temperature increases, the peak shifts to shorter wavelengths, producing first a red glow, then a white one and finally a blue-white colour as the peak moves out of the visible part of the spectrum and into

11557-401: The infrared radiation. EMR in this range causes molecular vibration and heating effects, which is how these animals detect it. Above the range of visible light, ultraviolet light becomes invisible to humans, mostly because it is absorbed by the cornea below 360 nm and the internal lens below 400 nm. Furthermore, the rods and cones located in the retina of the human eye cannot detect

11684-505: The inner structure of the mysterious Eta Carinae . In March 2011, the PIONIER instrument for the first time simultaneously combined the light of the four Unit Telescopes, potentially making VLTI the biggest optical telescope in the world. However, this attempt was not really a success. The first successful attempt was in February 2012, with four telescopes combined into a 130-meter diameter mirror. In March 2019, ESO astronomers, employing

11811-457: The intense gravity close to the central black hole. Using the VLT, astronomers have also estimated the age of extremely old stars in the NGC 6397 cluster. Based on stellar evolution models, two stars were found to be 13.4 ± 0.8 billion years old, that is, they are from the earliest era of star formation in the Universe. They have also analysed the atmosphere around a super-Earth exoplanet for

11938-399: The light via tunnels to the central VLTI beam-combiners. The maximum field-of-view (at Nasmyth foci) is around 27 arcminutes diameter, slightly smaller than the full moon, though most instruments view a narrower field. Each telescope has an alt-azimuth mount with total mass around 350 tonnes, and uses active optics with 150 supports on the back of the primary mirror to control the shape of

12065-426: The luminous body, rejecting the "forms" of Ibn al-Haytham and Witelo as well as the "species" of Roger Bacon , Robert Grosseteste and Johannes Kepler . In 1637 he published a theory of the refraction of light that assumed, incorrectly, that light travelled faster in a denser medium than in a less dense medium. Descartes arrived at this conclusion by analogy with the behaviour of sound waves. Although Descartes

12192-418: The main delay line, beam compressor and feeding optics. Additionally, the interferometric technique is such that it is very efficient only for objects that are small enough that all their light is concentrated. For instance, an object with a relatively low surface brightness such as the moon cannot be observed, because its light is too diluted. Only targets which are at temperatures of more than 1,000° C have

12319-496: The monotony of the desert and is located in the coastal plains, south of Mejillones Peninsula and north of " Cerro Coloso ". The Tropic of Capricorn passes in the north of the city, outside the urban area, which is located the Cerro Moreno International Airport . The Tropic of Capricorn Monument was opened on 21 December 2000 in celebration of this. Designed by the architect Eleonora Roman, it

12446-413: The movement of matter. He wrote, "radiation will exert pressure on both sides of the plate. The forces of pressure exerted on the two sides are equal if the plate is at rest. However, if it is in motion, more radiation will be reflected on the surface that is ahead during the motion (front surface) than on the back surface. The backwardacting force of pressure exerted on the front surface is thus larger than

12573-483: The needs of the observing project. The reconfigurable nature of the VLTI is similar to that of the Very Large Array . Results from the VLT have led to the publication of an average of more than one peer-reviewed scientific paper per day. For instance in 2017, over 600 refereed scientific papers were published based on VLT data. The telescope's scientific discoveries include direct imaging of Beta Pictoris b ,

12700-503: The observing conditions, for instance from air turbulence in the telescope tube, which might otherwise occur due to variations in the temperature and wind flow. The principal role of the main VLT telescopes is to operate as four independent telescopes. The interferometry (combining light from multiple telescopes) is used about 20 percent of the time for very high-resolution on bright objects, for example, on Betelgeuse . This mode allows astronomers to see details up to 25 times finer than with

12827-498: The opposite. At that time, the speed of light could not be measured accurately enough to decide which theory was correct. The first to make a sufficiently accurate measurement was Léon Foucault , in 1850. His result supported the wave theory, and the classical particle theory was finally abandoned (only to partly re-emerge in the twentieth century as photons in quantum theory ). Antofagasta Antofagasta ( Spanish pronunciation: [antofaˈɣasta] )

12954-414: The performance of the main delay lines . Note that this only applies to the interferometer and not other instruments on Paranal. In 2005, the VLTI was routinely producing observations, although with a brighter limiting magnitude and poorer observing efficiency than expected. As of March 2008, the VLTI had already led to the publication of 89 peer-reviewed publications and had published a first-ever image of

13081-436: The popular description of light being "stopped" in these experiments refers only to light being stored in the excited states of atoms, then re-emitted at an arbitrary later time, as stimulated by a second laser pulse. During the time it had "stopped", it had ceased to be light. The study of light and the interaction of light and matter is termed optics . The observation and study of optical phenomena such as rainbows and

13208-511: The scientific objectives of CRIRES+ is in-transit spectroscopy of exoplanets, which currently provides us with the only means of studying exoplanetary atmospheres. Transiting planets are almost always close-in planets that are hot and radiate most of their light in the infrared (IR) . Furthermore, the IR is a spectral region where lines of molecular gases like carbon monoxide (CO) , ammonia (NH 3 ) , and methane (CH 4 ) , etc. are expected from

13335-601: The spectrum of each atom. Emission can be spontaneous , as in light-emitting diodes , gas discharge lamps (such as neon lamps and neon signs , mercury-vapor lamps , etc.) and flames (light from the hot gas itself—so, for example, sodium in a gas flame emits characteristic yellow light). Emission can also be stimulated , as in a laser or a microwave maser . Deceleration of a free charged particle, such as an electron , can produce visible radiation: cyclotron radiation , synchrotron radiation and bremsstrahlung radiation are all examples of this. Particles moving through

13462-435: The speed of light throughout history. Galileo attempted to measure the speed of light in the seventeenth century. An early experiment to measure the speed of light was conducted by Ole Rømer , a Danish physicist, in 1676. Using a telescope , Rømer observed the motions of Jupiter and one of its moons , Io . Noting discrepancies in the apparent period of Io's orbit, he calculated that light takes about 22 minutes to traverse

13589-406: The sun". The Indian Buddhists , such as Dignāga in the fifth century and Dharmakirti in the seventh century, developed a type of atomism that is a philosophy about reality being composed of atomic entities that are momentary flashes of light or energy. They viewed light as being an atomic entity equivalent to energy. René Descartes (1596–1650) held that light was a mechanical property of

13716-483: The thin (177mm thick) mirror by computers. The VLT instrumentation programme is the most ambitious programme ever conceived for a single observatory. It includes large-field imagers, adaptive optics corrected cameras and spectrographs, as well as high-resolution and multi-object spectrographs and covers a broad spectral region, from deep ultraviolet (300 nm) to mid-infrared (24 μm) wavelengths. In addition to these, GRAVITY and MATISSE are currently installed in

13843-430: The treaty of 1874 , since the contract was not yet in force at that date. Bolivia suspended the tax in deference to the government of Chile, but following a note from the Chilean foreign minister, it reactivated the tax law, then cancelled and closed the "Compañía de Salitres". Faced with a looming conflict with Chile, Bolivia decided to claim support under the agreement signed with Peru, and the treaty became effective with

13970-486: The ultraviolet. These colours can be seen when metal is heated to "red hot" or "white hot". Blue-white thermal emission is not often seen, except in stars (the commonly seen pure-blue colour in a gas flame or a welder 's torch is in fact due to molecular emission, notably by CH radicals emitting a wavelength band around 425 nm and is not seen in stars or pure thermal radiation). Atoms emit and absorb light at characteristic energies. This produces " emission lines " in

14097-484: The use of large telescope diameters and adaptive optics correction can improve the sensitivity, this cannot extend the reach of optical interferometry beyond nearby stars and the brightest active galactic nuclei . Because the Unit Telescopes are used most of the time independently, they are used in the interferometric mode mostly during bright time (that is, close to full moon). At other times, interferometry

14224-624: The very short (below 360 nm) ultraviolet wavelengths and are in fact damaged by ultraviolet. Many animals with eyes that do not require lenses (such as insects and shrimp) are able to detect ultraviolet, by quantum photon-absorption mechanisms, in much the same chemical way that humans detect visible light. Various sources define visible light as narrowly as 420–680 nm to as broadly as 380–800 nm. Under ideal laboratory conditions, people can see infrared up to at least 1,050 nm; children and young adults may perceive ultraviolet wavelengths down to about 310–313 nm. Plant growth

14351-427: The visible region of the electromagnetic spectrum when plotted in wavelength units, and roughly 44% of the radiation that reaches the ground is visible. Another example is incandescent light bulbs , which emit only around 10% of their energy as visible light and the remainder as infrared. A common thermal light source in history is the glowing solid particles in flames , but these also emit most of their radiation in

14478-522: The war, a pact of truce was signed between Bolivia and Chile in 1884, which stated that the territory between the Loa River and parallel 23 would be under the administration of Chile, while Bolivia would be allowed access to the ports of Arica and Antofagasta. The Treaty of Peace and Friendship between Chile and Bolivia , signed on 20 October 1904, and promulgated on 21 March 1905, established in perpetuity border between Chile and Bolivia. In 1912,

14605-578: The warmest month, January, is 17.5 °C (63.5 °F) while the average daily high temperature is 23.2 °C (73.8 °F). The coldest month, July, sees an average low temperature of 11.8 °C (53.2 °F) and an average high temperature of 16.5 °C (61.7 °F). The highest temperature recorded is 30.0 °C (86.0 °F) in January 1998 and the lowest recorded is 3.0 °C (37.4 °F) in September 1978. The Atacama Desert coast

14732-480: The wave theory was that light waves, like sound waves, would need a medium for transmission. The existence of the hypothetical substance luminiferous aether proposed by Huygens in 1678 was cast into strong doubt in the late nineteenth century by the Michelson–Morley experiment . Newton's corpuscular theory implied that light would travel faster in a denser medium, while the wave theory of Huygens and others implied

14859-609: The world. This important trade fair generated a portfolio of U.S. $ 41,291 million (63.48% world total), for the period 2007–2015. In 2024, Antofagasta is the fifth most expensive city in Chile as to cost of living. Santiago, Punta Arenas, Puerto Varas and San Antonio have a higher cost of living. According to the 2002 census of the National Statistics Institute , Antofagasta had 296,905 inhabitants spread over an area of 30,718 km (11,860 sq mi), of which 143,685 are women and 153,220 were men. In

14986-531: Was awarded the installation of the Casino Enjoy Antofagasta . In the municipal elections of 2008, the first female mayor of the city, Dra. Marcela Hernando, was elected, who retired from her political party to run as an independent. This allowed her to have diverse support from all sectors of the population of Antofagasta. The city has an average elevation of 40 m (131 ft). The urban area of Antofagasta begins abruptly, breaking

15113-604: Was called " La Chimba ". After the tsunami in Iquique and the [ On 8 May 1872, Antofagasta was designated by the Bolivian Government as Puerto Mayor , opening trade worldwide. Next year, on 25 January 1872, following a session led by the prefect of the Provincial Department of Mejillones , Manuel Buitrago founded the Municipality of Antofagasta under Bolivian Law of Municipalities, which formed

15240-630: Was created to point the Tropic of Capricorn and to work as a Solar Calendar. Antofagasta was declared a partial common in the border area 20 July 1999, by Supreme Decree No. 1166 of the Ministry of Foreign Affairs . The city has little vegetation because it is situated in the Atacama Desert , which is the world's driest nonpolar desert. However, among the vegetated areas are a series of urban wetlands . Native reptiles, arthropods , birds like

15367-576: Was emitted in all directions as a series of waves in a medium called the luminiferous aether . As waves are not affected by gravity, it was assumed that they slowed down upon entering a denser medium. The wave theory predicted that light waves could interfere with each other like sound waves (as noted around 1800 by Thomas Young ). Young showed by means of a diffraction experiment that light behaved as waves. He also proposed that different colours were caused by different wavelengths of light and explained colour vision in terms of three-coloured receptors in

15494-432: Was for the first time qualitatively explained by Newton using the particle theory. Étienne-Louis Malus in 1810 created a mathematical particle theory of polarization. Jean-Baptiste Biot in 1812 showed that this theory explained all known phenomena of light polarization. At that time the polarization was considered as the proof of the particle theory. To explain the origin of colours , Robert Hooke (1635–1703) developed

15621-404: Was incorrect about the relative speeds, he was correct in assuming that light behaved like a wave and in concluding that refraction could be explained by the speed of light in different media. Descartes is not the first to use the mechanical analogies but because he clearly asserts that light is only a mechanical property of the luminous body and the transmitting medium, Descartes's theory of light

15748-427: Was initially designed to perform coherent integration (which requires signal-to-noise greater than one in each atmospheric coherence time). Using the big telescopes and coherent integration, the faintest object the VLTI can observe is magnitude 7 in the near infrared for broadband observations, similar to many other near infrared / optical interferometers without fringe tracking. In 2011, an incoherent integration mode

15875-505: Was introduced called AMBER "blind mode", which is more similar to the observation mode used at earlier interferometer arrays such as COAST, IOTA and CHARA. In this "blind mode", AMBER can observe sources as faint as K=10 in medium spectral resolution. At more challenging mid-infrared wavelengths, the VLTI can reach magnitude 4.5, significantly fainter than the Infrared Spatial Interferometer . When fringe tracking

16002-521: Was placed in the path of the light beam as it traveled from the source, to the mirror and then returned to its origin. Fizeau found that at a certain rate of rotation, the beam would pass through one gap in the wheel on the way out and the next gap on the way back. Knowing the distance to the mirror, the number of teeth on the wheel and the rate of rotation, Fizeau was able to calculate the speed of light as 313 000 000  m/s . Léon Foucault carried out an experiment which used rotating mirrors to obtain

16129-420: Was some confusion as to whether Yepun actually stands for the evening star Venus, because a Spanish-Mapuche dictionary from the 1940s wrongly translated Yepun as "Sirius". Although the four 8.2-metre Unit Telescopes can be combined in the VLTI , their observation time is spent mostly on individual observations, and are used for interferometric observations for a limited number of nights every year. However,

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