1.
Constellation
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A constellation is formally defined as a region of the celestial sphere, with boundaries laid down by the International Astronomical Union. The constellation areas mostly had their origins in Western-traditional patterns of stars from which the constellations take their names, in 1922, the International Astronomical Union officially recognized the 88 modern constellations, which cover the entire sky. They began as the 48 classical Greek constellations laid down by Ptolemy in the Almagest, Constellations in the far southern sky are late 16th- and mid 18th-century constructions. 12 of the 88 constellations compose the zodiac signs, though the positions of the constellations only loosely match the dates assigned to them in astrology. The term constellation can refer to the stars within the boundaries of that constellation. Notable groupings of stars that do not form a constellation are called asterisms, when astronomers say something is “in” a given constellation they mean it is within those official boundaries. Any given point in a coordinate system can unambiguously be assigned to a single constellation. Many astronomical naming systems give the constellation in which an object is found along with a designation in order to convey a rough idea in which part of the sky it is located. For example, the Flamsteed designation for bright stars consists of a number, the word constellation seems to come from the Late Latin term cōnstellātiō, which can be translated as set of stars, and came into use in English during the 14th century. It also denotes 88 named groups of stars in the shape of stellar-patterns, the Ancient Greek word for constellation was ἄστρον. Colloquial usage does not draw a distinction between constellation in the sense of an asterism and constellation in the sense of an area surrounding an asterism. The modern system of constellations used in astronomy employs the latter concept, the term circumpolar constellation is used for any constellation that, from a particular latitude on Earth, never sets below the horizon. From the North Pole or South Pole, all constellations south or north of the equator are circumpolar constellations. In the equatorial or temperate latitudes, the term equatorial constellation has sometimes been used for constellations that lie to the opposite the circumpolar constellations. They generally include all constellations that intersect the celestial equator or part of the zodiac, usually the only thing the stars in a constellation have in common is that they appear near each other in the sky when viewed from the Earth. In galactic space, the stars of a constellation usually lie at a variety of distances, since stars also travel on their own orbits through the Milky Way, the star patterns of the constellations change slowly over time. After tens to hundreds of thousands of years, their familiar outlines will become unrecognisable, the terms chosen for the constellation themselves, together with the appearance of a constellation, may reveal where and when its constellation makers lived. The earliest direct evidence for the constellations comes from inscribed stones and it seems that the bulk of the Mesopotamian constellations were created within a relatively short interval from around 1300 to 1000 BC
2.
Earth
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Earth, otherwise known as the World, or the Globe, is the third planet from the Sun and the only object in the Universe known to harbor life. It is the densest planet in the Solar System and the largest of the four terrestrial planets, according to radiometric dating and other sources of evidence, Earth formed about 4.54 billion years ago. Earths gravity interacts with objects in space, especially the Sun. During one orbit around the Sun, Earth rotates about its axis over 365 times, thus, Earths axis of rotation is tilted, producing seasonal variations on the planets surface. The gravitational interaction between the Earth and Moon causes ocean tides, stabilizes the Earths orientation on its axis, Earths lithosphere is divided into several rigid tectonic plates that migrate across the surface over periods of many millions of years. About 71% of Earths surface is covered with water, mostly by its oceans, the remaining 29% is land consisting of continents and islands that together have many lakes, rivers and other sources of water that contribute to the hydrosphere. The majority of Earths polar regions are covered in ice, including the Antarctic ice sheet, Earths interior remains active with a solid iron inner core, a liquid outer core that generates the Earths magnetic field, and a convecting mantle that drives plate tectonics. Within the first billion years of Earths history, life appeared in the oceans and began to affect the Earths atmosphere and surface, some geological evidence indicates that life may have arisen as much as 4.1 billion years ago. Since then, the combination of Earths distance from the Sun, physical properties, in the history of the Earth, biodiversity has gone through long periods of expansion, occasionally punctuated by mass extinction events. Over 99% of all species that lived on Earth are extinct. Estimates of the number of species on Earth today vary widely, over 7.4 billion humans live on Earth and depend on its biosphere and minerals for their survival. Humans have developed diverse societies and cultures, politically, the world has about 200 sovereign states, the modern English word Earth developed from a wide variety of Middle English forms, which derived from an Old English noun most often spelled eorðe. It has cognates in every Germanic language, and their proto-Germanic root has been reconstructed as *erþō, originally, earth was written in lowercase, and from early Middle English, its definite sense as the globe was expressed as the earth. By early Modern English, many nouns were capitalized, and the became the Earth. More recently, the name is simply given as Earth. House styles now vary, Oxford spelling recognizes the lowercase form as the most common, another convention capitalizes Earth when appearing as a name but writes it in lowercase when preceded by the. It almost always appears in lowercase in colloquial expressions such as what on earth are you doing, the oldest material found in the Solar System is dated to 4. 5672±0.0006 billion years ago. By 4. 54±0.04 Gya the primordial Earth had formed, the formation and evolution of Solar System bodies occurred along with the Sun
3.
Star system
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A star system or stellar system is a small number of stars that orbit each other, bound by gravitational attraction. A large number of stars bound by gravitation is generally called a cluster or galaxy, although, broadly speaking. Star systems are not to be confused with planetary systems, which include planets, a star system of two stars is known as a binary star, binary star system or physical double star. Examples of binary systems are Sirius, Procyon and Cygnus X-1, the last of which consists of a star. A multiple star system consists of three or more stars that appear from Earth to be close to one another in the sky, physical multiple stars are also commonly called multiple stars or multiple star systems. Most multiple star systems are triple stars, systems with four or more components are less likely to occur. These systems are smaller than open star clusters, which have more complex dynamics, most multiple star systems known are triple, for higher multiplicities, the number of known systems with a given multiplicity decreases exponentially with multiplicity. For example, in the 1999 revision of Tokovinins catalog of physical multiple stars,551 out of the 728 systems described are triple, however, because of selection effects, knowledge of these statistics is very incomplete. Each of these groups must also be hierarchical, which means that they must be divided into smaller subgroups which themselves are hierarchical. Each level of the hierarchy can be treated as a problem by considering close pairs as if they were a single star. In a physical triple star system, each orbits the center of mass of the system. Usually, two of the form a close binary system, and the third orbits this pair at a distance much larger than that of the binary orbit. The reason for this is if the inner and outer orbits are comparable in size. Triple stars that are not all gravitationally bound might comprise a physical binary and a companion, such as Beta Cephei, or rarely. Hierarchical multiple star systems with more than three stars can produce a number of more complicated arrangements, which can be illustrated by what Evans has called a mobile diagram and these are similar to ornamental mobiles hung from the ceiling. Some examples can be seen in the figure to the right, each level of the diagram illustrates the decomposition of the system into two or more systems with smaller size. Evans calls a diagram multiplex if there is a node with more than two children, i. e. if the decomposition of some subsystem involves two or more orbits with comparable size. Because, as we have seen for triple stars, this may be unstable, multiple stars are expected to be simplex
4.
Planetary nebula
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A planetary nebula, often abbreviated as PN or plural PNe, is a kind of emission nebula consisting of an expanding, glowing shell of ionized gas ejected from old red giant stars late in their lives. Herschels name for these objects was popularly adopted and has not been changed and they are a relatively short-lived phenomenon, lasting a few tens of thousands of years, compared to a typical stellar lifetime of several billion years. After most of the red giants atmosphere is dissipated, the radiation of the hot luminous core, called a planetary nebula nucleus. Absorbed ultraviolet light energises the shell of gas around the central star. Planetary nebulae likely play a role in the chemical evolution of the Milky Way by expelling elements to the interstellar medium from stars where those elements were created. Planetary nebulae are also observed in distant galaxies, yielding useful information about their chemical abundances. Starting from the 1990s, Hubble Space Telescope images have revealed many planetary nebulae to have extremely complex, about one-fifth are roughly spherical, but the majority are not spherically symmetric. The mechanisms that produce such a variety of shapes and features are not yet well understood. The first planetary nebula discovered was the Dumbbell Nebula in the constellation of Vulpecula and it was observed by Charles Messier in 1764 and listed as M27 in his catalogue of nebulous objects. To early observers with telescopes, M27 and subsequently discovered planetary nebulae resembled the giant planets like Uranus. William Herschel, discoverer of Uranus, eventually coined the term planetary nebula, the nature of planetary nebulae was unknown until the first spectroscopic observations were made in the mid-19th century. Using a prism to disperse their light, William Huggins was one of the earliest astronomers to study the spectra of astronomical objects. On August 29,1864, Huggins was the first to analyze the spectrum of a planetary nebula when he observed Cats Eye Nebula and his observations of stars showed that their spectra consisted of a continuum of radiation with many dark lines superimposed. He later found that many objects such as the Andromeda Nebula had spectra that were quite similar. Those nebulae were later shown to be collections of stars now called galaxies, however, when Huggins looked at the Cats Eye Nebula, he found a very different spectrum. Rather than a strong continuum with absorption lines superimposed, the Cats Eye Nebula, the brightest of these was at a wavelength of 500.7 nanometres, which did not correspond with a line of any known element. At first, it was hypothesized that the line might be due to an unknown element, a similar idea had led to the discovery of helium through analysis of the Suns spectrum in 1868. While helium was isolated on Earth soon after its discovery in the spectrum of the Sun, nebulium was not
5.
Star
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A star is a luminous sphere of plasma held together by its own gravity. The nearest star to Earth is the Sun, many other stars are visible to the naked eye from Earth during the night, appearing as a multitude of fixed luminous points in the sky due to their immense distance from Earth. Historically, the most prominent stars were grouped into constellations and asterisms, astronomers have assembled star catalogues that identify the known stars and provide standardized stellar designations. However, most of the stars in the Universe, including all stars outside our galaxy, indeed, most are invisible from Earth even through the most powerful telescopes. Almost all naturally occurring elements heavier than helium are created by stellar nucleosynthesis during the stars lifetime, near the end of its life, a star can also contain degenerate matter. Astronomers can determine the mass, age, metallicity, and many properties of a star by observing its motion through space, its luminosity. The total mass of a star is the factor that determines its evolution. Other characteristics of a star, including diameter and temperature, change over its life, while the environment affects its rotation. A plot of the temperature of stars against their luminosities produces a plot known as a Hertzsprung–Russell diagram. Plotting a particular star on that allows the age and evolutionary state of that star to be determined. A stars life begins with the collapse of a gaseous nebula of material composed primarily of hydrogen, along with helium. When the stellar core is sufficiently dense, hydrogen becomes steadily converted into helium through nuclear fusion, the remainder of the stars interior carries energy away from the core through a combination of radiative and convective heat transfer processes. The stars internal pressure prevents it from collapsing further under its own gravity, a star with mass greater than 0.4 times the Suns will expand to become a red giant when the hydrogen fuel in its core is exhausted. In some cases, it will fuse heavier elements at the core or in shells around the core, as the star expands it throws a part of its mass, enriched with those heavier elements, into the interstellar environment, to be recycled later as new stars. Meanwhile, the core becomes a remnant, a white dwarf. Binary and multi-star systems consist of two or more stars that are bound and generally move around each other in stable orbits. When two such stars have a close orbit, their gravitational interaction can have a significant impact on their evolution. Stars can form part of a much larger gravitationally bound structure, historically, stars have been important to civilizations throughout the world
6.
Siding Spring Observatory
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The observatory is situated 1,165 metres above sea level in the Warrumbungle National Park on Mount Woorat, also known as Siding Spring Mountain. Siding Spring Observatory is owned by the Australian National University and is part of the Mount Stromlo, more than A$100 million worth of research equipment is located at the observatory. There are 52 telescopes on site, the original Mount Stromlo Observatory was set up by the Commonwealth Government in 1924. After duty supplying optical components to the military in World War II, between 1953 and 1974, the 74-inch reflecting telescope at Mount Stromlo was the largest optical telescope in Australia. Already in the 1950s, the lights of Canberra, ACT, had brightened the sky at Mount Stromlo to such an extent that many faint astronomical objects had been overwhelmed by light pollution. The search for a new site was initiated by Bart Bok, after a site survey was undertaken the number of possible locations was narrowed down to two — Siding Spring and Mount Bingar near Griffith, also in New South Wales. Siding Spring was first suggested for astronomy by Harley Wood, the New South Wales Government Astronomer at the time, arthur Hogg did much of the preliminary site testing. The Siding Spring site was selected by the ANU in 1962 from many possible locations because of the dark. By the mid-1960s the ANU had set up three telescopes, together with supporting facilities, such as sealed roads, staff accommodation, electricity and water. In 1984, the Prime Minister, Bob Hawke, opened the ANUs largest telescope, since the 1950s, and quite independently of developments at Siding Spring, the Australian and British governments had been negotiating about the construction of a very large telescope. During the construction of the AAT in the early 1970s, the British Science Research Council also built the UK Schmidt Telescope,1 kilometre to the northeast of the AAT dome. The considerably wider field of view of the Schmidt optical design complements the narrower field of the AAT, interesting objects so discovered are then studied in greater detail on the larger instrument. In 1987, the Schmidt Telescope was amalgamated with the AAT, Siding Spring Observatory also houses many telescopes from institutions across the world including, Korea, America, the U. K. Poland, Hungary, Germany and Russia. In 1990, the earth-satellite tracking facility of the Royal Greenwich Observatory was closed down after 10 years of operation, las Cumbres Observatory Global Telescope Network operate a 2-metre Ritchey Chretien telescope used for research, citizen science, and education purposes by users across the globe. Currently there are one thousand registered users of the Faulkes Telescopes. The wide field of view and the fast response permit measurements inaccessible to conventional instruments. HAT-South is a project to search for transiting planets in the Southern Hemisphere. It uses a network of telescopes to monitor hundreds of thousands of bright stars
7.
Boomerang
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A boomerang is a tool, typically constructed as a flat air foil that, when thrown, is designed to spin about an axis perpendicular to the direction of its flight. A returning boomerang is designed to return to the thrower and it is well known as a weapon used by Indigenous Australians for hunting. Boomerangs have been used for hunting, as well as a sport. They are commonly thought of as an Australian icon, and come in shapes and sizes. A boomerang is traditionally a wooden device, although historically boomerang-like devices have also been made from bones. Modern boomerangs used for sport are often made from thin aircraft plywood, plastics such as ABS, polypropylene, phenolic paper, Boomerangs come in many shapes and sizes depending on their geographic or tribal origins and intended function. An important distinction should be made between returning boomerangs and non-returning boomerangs, Returning boomerangs fly and are examples of the earliest heavier-than-air man-made flight. While a throwing stick can also be shaped overall like a boomerang, it is designed to travel as straight as possible so that it can be aimed. Its surfaces therefore are symmetrical and not uneven like the aerofoils which give the returning boomerang its characteristic curved flight, Returning boomerangs were also used to decoy birds of prey, thrown above long grass to frighten game birds into flight and into waiting nets. Modern returning boomerangs can be of various shapes or sizes as can be seen in a photo in the Modern use section. Historical evidence also points to the use of non-returning boomerangs by the Native Americans of California and Arizona, indeed, some boomerangs were not thrown at all, but were used in hand to hand combat by Indigenous Australians. Ancient Egyptian examples, however, have recovered and experiments have shown that they functioned as returning boomerangs. Boomerangs can be used as hunting weapons, percussive musical instruments, battle clubs, fire-starters, decoys for hunting waterfowl. The smallest boomerang may be less than 10 centimetres from tip to tip, tribal boomerangs may be inscribed and/or painted with designs meaningful to their makers. Most boomerangs seen today are of the tourist or competition sort, the origin of the term is mostly certain, but many researchers have different theories on how the word entered into the English vocabulary. The boomerang was first encountered by people at Farm Cove, Australia, in December 1804. David Collins listed Wo-mur-rāng as one of eight aboriginal Names of clubs in 1798, a 1790 anonymous manuscript on aboriginal language of New South Wales reported Boo-mer-rit as the Scimiter. In 1822 it was described in detail and recorded as a bou-mar-rang, the Turawal used other words for their hunting sticks but used boomerang to refer to a returning throw-stick
8.
Hubble Space Telescope
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The Hubble Space Telescope is a space telescope that was launched into low Earth orbit in 1990 and remains in operation. Although not the first space telescope, Hubble is one of the largest and most versatile, with a 2. 4-meter mirror, Hubbles four main instruments observe in the near ultraviolet, visible, and near infrared spectra. Hubbles orbit outside the distortion of Earths atmosphere allows it to take extremely high-resolution images, Hubble has recorded some of the most detailed visible light images ever, allowing a deep view into space and time. Many Hubble observations have led to breakthroughs in astrophysics, such as determining the rate of expansion of the universe. The HST was built by the United States space agency NASA, the Space Telescope Science Institute selects Hubbles targets and processes the resulting data, while the Goddard Space Flight Center controls the spacecraft. Space telescopes were proposed as early as 1923, Hubble was funded in the 1970s, with a proposed launch in 1983, but the project was beset by technical delays, budget problems, and the Challenger disaster. When finally launched in 1990, Hubbles main mirror was found to have been ground incorrectly, the optics were corrected to their intended quality by a servicing mission in 1993. Hubble is the telescope designed to be serviced in space by astronauts. After launch by Space Shuttle Discovery in 1990, five subsequent Space Shuttle missions repaired, upgraded, the fifth mission was canceled on safety grounds following the Columbia disaster. However, after spirited public discussion, NASA administrator Mike Griffin approved the fifth servicing mission, the telescope is operating as of 2017, and could last until 2030–2040. Its scientific successor, the James Webb Space Telescope, is scheduled for launch in 2018, the history of the Hubble Space Telescope can be traced back as far as 1946, to the astronomer Lyman Spitzers paper Astronomical advantages of an extraterrestrial observatory. In it, he discussed the two advantages that a space-based observatory would have over ground-based telescopes. First, the resolution would be limited only by diffraction, rather than by the turbulence in the atmosphere. Second, a telescope could observe infrared and ultraviolet light. Spitzer devoted much of his career to pushing for the development of a space telescope, space-based astronomy had begun on a very small scale following World War II, as scientists made use of developments that had taken place in rocket technology. An orbiting solar telescope was launched in 1962 by the United Kingdom as part of the Ariel space program, oAO-1s battery failed after three days, terminating the mission. It was followed by OAO-2, which carried out observations of stars and galaxies from its launch in 1968 until 1972. The continuing success of the OAO program encouraged increasingly strong consensus within the community that the LST should be a major goal
9.
Swedish-ESO Submillimetre Telescope
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The Swedish-ESO Submillimetre Telescope was a radio telescope of diameter 15 metres located at the La Silla Observatory in Chile. The telescope was built in 1987 as a project between ESO and Onsala Space Observatory, with contributions from Finland and Australia. It was then the large telescope for submillimetre astronomy in the southern hemisphere. In 1995 observations made with SEST showed that the Boomerang Nebula is the coldest known location in the universe, with a temperature lower than the background radiation
10.
Chile
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Chile, officially the Republic of Chile, is a South American country occupying a long, narrow strip of land between the Andes to the east and the Pacific Ocean to the west. It borders Peru to the north, Bolivia to the northeast, Argentina to the east, Chilean territory includes the Pacific islands of Juan Fernández, Salas y Gómez, Desventuradas, and Easter Island in Oceania. Chile also claims about 1,250,000 square kilometres of Antarctica, the arid Atacama Desert in northern Chile contains great mineral wealth, principally copper. Southern Chile is rich in forests and grazing lands, and features a string of volcanoes and lakes, the southern coast is a labyrinth of fjords, inlets, canals, twisting peninsulas, and islands. Spain conquered and colonized Chile in the century, replacing Inca rule in northern and central Chile. After declaring its independence from Spain in 1818, Chile emerged in the 1830s as a relatively stable authoritarian republic, in the 1960s and 1970s the country experienced severe left-right political polarization and turmoil. The regime, headed by Augusto Pinochet, ended in 1990 after it lost a referendum in 1988 and was succeeded by a coalition which ruled through four presidencies until 2010. Chile is today one of South Americas most stable and prosperous nations and it leads Latin American nations in rankings of human development, competitiveness, income per capita, globalization, state of peace, economic freedom, and low perception of corruption. It also ranks high regionally in sustainability of the state, Chile is a founding member of the United Nations, the Union of South American Nations and the Community of Latin American and Caribbean States. There are various theories about the origin of the word Chile, another theory points to the similarity of the valley of the Aconcagua with that of the Casma Valley in Peru, where there was a town and valley named Chili. Another origin attributed to chilli is the onomatopoeic cheele-cheele—the Mapuche imitation of the warble of a locally known as trile. The Spanish conquistadors heard about this name from the Incas, ultimately, Almagro is credited with the universalization of the name Chile, after naming the Mapocho valley as such. The older spelling Chili was in use in English until at least 1900 before switching over to Chile, stone tool evidence indicates humans sporadically frequented the Monte Verde valley area as long as 18,500 years ago. About 10,000 years ago, migrating Native Americans settled in fertile valleys, settlement sites from very early human habitation include Monte Verde, Cueva del Milodon and the Pali Aike Craters lava tube. They fought against the Sapa Inca Tupac Yupanqui and his army, the result of the bloody three-day confrontation known as the Battle of the Maule was that the Inca conquest of the territories of Chile ended at the Maule river. The next Europeans to reach Chile were Diego de Almagro and his band of Spanish conquistadors, the Spanish encountered various cultures that supported themselves principally through slash-and-burn agriculture and hunting. The conquest of Chile began in earnest in 1540 and was carried out by Pedro de Valdivia, one of Francisco Pizarros lieutenants, who founded the city of Santiago on 12 February 1541. Although the Spanish did not find the gold and silver they sought, they recognized the agricultural potential of Chiles central valley
11.
Big Bang
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The Big Bang theory is the prevailing cosmological model for the universe from the earliest known periods through its subsequent large-scale evolution. If the known laws of physics are extrapolated to the highest density regime, detailed measurements of the expansion rate of the universe place this moment at approximately 13.8 billion years ago, which is thus considered the age of the universe. After the initial expansion, the universe cooled sufficiently to allow the formation of subatomic particles, giant clouds of these primordial elements later coalesced through gravity in halos of dark matter, eventually forming the stars and galaxies visible today. Since Georges Lemaître first noted in 1927 that a universe could be traced back in time to an originating single point. More recently, measurements of the redshifts of supernovae indicate that the expansion of the universe is accelerating, the known physical laws of nature can be used to calculate the characteristics of the universe in detail back in time to an initial state of extreme density and temperature. American astronomer Edwin Hubble observed that the distances to faraway galaxies were strongly correlated with their redshifts, assuming the Copernican principle, the only remaining interpretation is that all observable regions of the universe are receding from all others. Since we know that the distance between galaxies increases today, it must mean that in the past galaxies were closer together, the continuous expansion of the universe implies that the universe was denser and hotter in the past. Large particle accelerators can replicate the conditions that prevailed after the early moments of the universe, resulting in confirmation, however, these accelerators can only probe so far into high energy regimes. Consequently, the state of the universe in the earliest instants of the Big Bang expansion is still poorly understood, the first subatomic particles to be formed included protons, neutrons, and electrons. Though simple atomic nuclei formed within the first three minutes after the Big Bang, thousands of years passed before the first electrically neutral atoms formed, the majority of atoms produced by the Big Bang were hydrogen, along with helium and traces of lithium. Giant clouds of primordial elements later coalesced through gravity to form stars and galaxies. The framework for the Big Bang model relies on Albert Einsteins theory of relativity and on simplifying assumptions such as homogeneity. The governing equations were formulated by Alexander Friedmann, and similar solutions were worked on by Willem de Sitter, extrapolation of the expansion of the universe backwards in time using general relativity yields an infinite density and temperature at a finite time in the past. This singularity indicates that general relativity is not a description of the laws of physics in this regime. How closely models based on general relativity alone can be used to extrapolate toward the singularity is debated—certainly no closer than the end of the Planck epoch. This primordial singularity is itself called the Big Bang, but the term can also refer to a more generic early hot. The agreement of independent measurements of this age supports the model that describes in detail the characteristics of the universe. The earliest phases of the Big Bang are subject to much speculation, in the most common models the universe was filled homogeneously and isotropically with a very high energy density and huge temperatures and pressures and was very rapidly expanding and cooling
12.
Atacama Large Millimeter Array
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The Atacama Large Millimeter Array is an astronomical interferometer of radio telescopes in the Atacama desert of northern Chile. ALMA is a partnership among Europe, the United States, Canada, Japan, South Korea, Taiwan. Costing about US$1.4 billion, it is the most expensive ground-based telescope in operation, ALMA began scientific observations in the second half of 2011 and the first images were released to the press on 3 October 2011. The array has been operational since March 2013. The initial ALMA array is composed of 66 high-precision antennas, the high sensitivity is mainly achieved through the large numbers of antenna dishes that will make up the array. The telescopes were provided by the European, North American and East Asian partners of ALMA, the American and European partners each provided twenty-five 12-meter diameter antennas, that compose the main array. The participating East Asian countries are contributing 16 antennas in the form of the Atacama Compact Array, by using smaller antennas than the main ALMA array, larger fields of view can be imaged at a given frequency using ACA. Placing the antennas closer together enables the imaging of sources of larger angular extent, the ACA works together with the main array in order to enhance the latters wide-field imaging capability. ALMA has its roots in three astronomical projects — the Millimeter Array of the United States, the Large Southern Array of Europe. The merged array combined the sensitivity of the LSA with the frequency coverage, ESO and NRAO worked together in technical, science, and management groups to define and organize a joint project between the two observatories with participation by Canada and Spain. A groundbreaking ceremony was held on November 6,2003 and the ALMA logo was unveiled and this was mainly for political reasons. Although very different approaches have been chosen by the providers, each of the antenna designs appears to be able to meet ALMAs stringent requirements, ALMA is the largest and most expensive ground-based astronomical project, costing between US$1.4 and 1.5 billion. S. Japanese, and Canadian companies and universities, three prototype antennas have undergone evaluation at the Very Large Array since 2002. The first antenna was delivered in 2008, the last in 2011, the solution chosen is to use two custom 28-wheel self-loading heavy haulers. The vehicles were made by Scheuerle Fahrzeugfabrik in Germany and are 10 m wide,20 m long and 6 m high and they are powered by twin turbocharged 500 kW Diesel engines. The transporters, which feature a drivers seat designed to accommodate an oxygen tank to aid breathing the thin high-altitude air, the first vehicle was completed and tested in July 2007. Both transporters were delivered to the ALMA Operations Support Facility in Chile on 15 February 2008, on 7 July 2008, an ALMA transporter moved an antenna for the first time, from inside the antenna assembly building to a pad outside the building for testing. During Autumn 2009, the first three antennas were transported one-by-one to the Array Operations Site, linking three antennas allows corrections of errors that can arise when only two antennas are used, thus paving the way for precise, high-resolution imaging
