Brovary
Brovary is a city in Kiev Oblast in northern Ukraine, an eastern suburb of the country's capital, Kiev. Administratively, it is incorporated as a town of oblast significance, it serves as the administrative centre of Brovary Raion, though it does not belong to the raion. Its population is 100,866 . Brovary is a historic town, first mentioned in 1630, its name, translated from Ukrainian, means "brewers". The city houses a railway station. International ill-fame came to the city in 2000 after one of its apartment blocks was hit by a stray surface-to-surface missile launched from a neighbouring army shooting range in Honcharivs'ke. Three people were killed. Today, Brovary is Ukraine's shoe-making capital with dozens of such companies located here. At Brovary, there is a broadcasting centre for long and shortwaves; the longwave transmitter, which works on 207 kHz, uses as its antenna two 259.6 m tall guyed mast radiators each equipped with a cage antenna at their lower part. Brovary is an important sport centre of Ukraine.
Several world and Olympic champions began their career here. Ukraine's national mint facility is located in Brovary. Brovary is a district centre in Kyiv region, it is situated 20 kilometers from the capital of Kyiv. Brovary district lies in the areas of mixed forests; the climate here is moderately continental with the middle temperature -6 C in January and +19 C in July. The territory of the region was populated ages ago by the ancestors of the current inhabitants – trypillians, who were the first in Europe to sow seeds of the well-known Ukrainian bread. Brovary was firstly mentioned in 1630. In that time there were only 60 or 70 houses in Brovary, but in 1649 a Cossack sotnya is known to have been formed there. Cossacks took; the town got its name after breweries. Travellers who went to Kiev stopped in Brovary, rested and drank the local tasty beer. Many famous people visited Brovary while travelling to Kiev. A Ukrainian poet, Taras Shevchenko, was among them, he visited this town many times in the period from 1829 to 1847.
Nowadays there is a monument to Shevchenko in the place from which Brovary began its history as a town, in its old centre. The modern centre of Brovary is the most beautiful part of the town. There, one will find a park with its peaceful alleys. In the central park you can see monuments to the past. There is a tank; some shops and cafes are situated there, so the streets are never empty in the evening. Traditionally the town is divided into 3 parts: the old town, the new town, the industrial part. There are a lot of plants and factories in the town, producing knitting, machine tools, plastic materials and other goods. There are 10 secondary schools, 2 music schools, a school of Arts, 3 libraries in Brovary. In the city center lies “Prometey”, the historical museum in Gagarin street, which attracts many visitors. If you are fond of sports, you may go to the swimming pools or to the “Spartak” stadium, or enter the sport college. In September the citizens of Brovary celebrate the Holiday of the Town’s Day.
It’s the time when everyone can watch and listen to concerts of musicians and singers, see performances by dancers who live in the district. On that day, all the competitions are for show, but Brovary itself is known to be a famous sports town, where a lot of well-known sportsmen have started their career. Oleksandra Kononova won three medals at the 2010 Paralympic games in Vancouver and became the 2010 Ukrainian sports personality of the year. Brovary is twinned with: Missile blasts Ukraine flats. History of broadcasting in Brovary Paspolini Studio
Lick Observatory
The Lick Observatory is an astronomical observatory and operated by the University of California. It is situated on the summit of Mount Hamilton, in the Diablo Range just east of San Jose, California, US; the observatory is managed by the University of California Observatories, with headquarters on the University of California, Santa Cruz campus, where its scientific staff moved in the mid-1960s. It is named after James Lick. Lick Observatory is the world's first permanently occupied mountain-top observatory; the observatory, in a Classical Revival style structure, was constructed between 1876 and 1887, from a bequest from James Lick of $700,000. Lick a carpenter and piano maker, chose the site atop Mount Hamilton and was buried there in 1887 under the future site of the telescope, with a brass tablet bearing the inscription, "Here lies the body of James Lick". Lick additionally requested that Santa Clara County construct a "first-class road" to the summit, completed in 1876. Lick chose John Wright, of San Francisco's Wright & Sanders firm of architects, to design both the Observatory and the Astronomer's House.
All of the construction materials had to be brought to the site by horse and mule-drawn wagons, which could not negotiate a steep grade. To keep the grade below 6.5%, the road had to take a winding and sinuous path, which the modern-day road still follows. Tradition maintains that this road has 365 turns; the road is closed. The first telescope installed at the observatory was a 12-inch refractor made by Alvan Clark. Astronomer E. E. Barnard used the telescope to make "exquisite photographs of comets and nebulae", according to D. J. Warner of Warner & Swasey Company; the 36-inch refracting telescope on Mt. Hamilton was Earth's largest refracting telescope during the period from when it saw first light on January 3, 1888, until the construction of Yerkes Observatory in 1897. Warner & Swasey designed and built the telescope mounting, with the 36-inch lens manufactured by one of the Clark sons, Alvan Graham. E. E. Barnard used the telescope in 1892 to discover a fifth moon of Amalthea; this was the first addition to Jupiter's known moons since Galileo observed the planet through his parchment tube and spectacle lens.
The telescope provided spectra for W. W. Campbell's work on the radial velocities of stars. In May 1888, the observatory was turned over to the Regents of the University of California, it became the first permanently occupied mountain-top observatory in the world. Edward Singleton Holden was the first director; the location provided excellent viewing performance because of lack of ambient pollution. When low cloud cover is present below the peak, light pollution is cut to nothing. On May 21, 1939, during a nighttime fog that engulfed the summit, a U. S. Army Air Force Northrop A-17 two-seater attack plane crashed into the main building; because a scientific meeting was being held elsewhere, the only staff member present was Nicholas Mayall. Nothing caught the two individuals in the building were unharmed; the pilot of the plane, Lt. Richard F. Lorenz, passenger Private W. E. Scott were killed instantly; the telephone line was broken by the crash, so no help could be called for at first. Help arrived together with numerous reporters and photographers, who kept arriving all night long.
Evidence of their numbers could be seen the next day by the litter of flash bulbs carpeting the parking lot. The press covered the accident and many reports emphasized the luck in not losing a large cabinet of spectrograms, knocked over by the crash coming through an astronomer's office window. More notable was the lack of fire or damage to a telescope dome. In 1950, the California state legislature appropriated funds for a 120-inch reflector telescope, completed in 1959; the observatory additionally has a 24-inch Cassegrain reflector dedicated to photoelectric measurements of star brightness, received a pair of 20-inch astrographs from the Carnegie Corporation. In 1886, Lick Observatory begins supplying Railroad Standard Time to the Southern Pacific Railroad, to other businesses, over telegraph lines; the signal was generated by a clock manufactured by E. Howard & Co. for the Observatory, which included an electric apparatus for transmitting the time signal over telegraph lines. While most of the nation's railroads received their time signal from the U.
S. Naval Observatory time signal via Western Union's telegraph lines, the Lick Observatory Time-Signal was used by railroads from the West coast all the way to Colorado. With the growth of San Jose, the rest of Silicon Valley, light pollution became a problem for the observatory. In the 1970s, a site in the Santa Lucia Mountains at Junípero Serra Peak, southeast of Monterey, was evaluated for possible relocation of many of the telescopes. However, funding for the move was not available, in 1980 San Jose began a program to reduce the effects of lighting, most notably replacing all streetlamps with low pressure sodium lamps; the result is that the Mount Hamilton site remains a viable location for a major working observatory. The International Astronomical Union named Asteroid 6216 San Jose to honor the city's efforts toward reducing light pollution. In 2006, there were 23 f
Ukraine
Ukraine, sometimes called the Ukraine, is a country in Eastern Europe. Excluding Crimea, Ukraine has a population of about 42.5 million, making it the 32nd most populous country in the world. Its capital and largest city is Kiev. Ukrainian is the official language and its alphabet is Cyrillic; the dominant religions in the country are Greek Catholicism. Ukraine is in a territorial dispute with Russia over the Crimean Peninsula, which Russia annexed in 2014. Including Crimea, Ukraine has an area of 603,628 km2, making it the largest country within Europe and the 46th largest country in the world; the territory of modern Ukraine has been inhabited since 32,000 BC. During the Middle Ages, the area was a key centre of East Slavic culture, with the powerful state of Kievan Rus' forming the basis of Ukrainian identity. Following its fragmentation in the 13th century, the territory was contested and divided by a variety of powers, including Lithuania, Austria-Hungary, the Ottoman Empire and Russia. A Cossack republic emerged and prospered during the 17th and 18th centuries, but its territory was split between Poland and the Russian Empire, merged into the Russian-dominated Soviet Union in the late 1940s as the Ukrainian Soviet Socialist Republic.
In 1991 Ukraine gained its independence from the Soviet Union in the aftermath of its dissolution at the end of the Cold War. Before its independence, Ukraine was referred to in English as "The Ukraine", but most sources have since moved to drop "the" from the name of Ukraine in all uses. Following its independence, Ukraine declared itself a neutral state. In 2013, after the government of President Viktor Yanukovych had decided to suspend the Ukraine-European Union Association Agreement and seek closer economic ties with Russia, a several-months-long wave of demonstrations and protests known as the Euromaidan began, which escalated into the 2014 Ukrainian revolution that led to the overthrow of Yanukovych and the establishment of a new government; these events formed the background for the annexation of Crimea by Russia in March 2014, the War in Donbass in April 2014. On 1 January 2016, Ukraine applied the economic component of the Deep and Comprehensive Free Trade Area with the European Union.
Ukraine is ranks 88th on the Human Development Index. As of 2018, Ukraine has the second lowest GDP per capita in Europe. At US$40, it has the lowest median wealth per adult in the world, it suffers from a high poverty rate and severe corruption. However, because of its extensive fertile farmlands, Ukraine is one of the world's largest grain exporters. Ukraine maintains the second-largest military in Europe after that of Russia; the country is home to a multi-ethnic population, 77.8 percent of whom are Ukrainians, followed by a large Russian minority, as well as Georgians, Belarusians, Crimean Tatars, Jews and Hungarians. Ukraine is a unitary republic under a semi-presidential system with separate powers: legislative and judicial branches; the country is a member of the United Nations, the Council of Europe, the OSCE, the GUAM organization, one of the founding states of the Commonwealth of Independent States. There are different hypotheses as to the etymology of the name Ukraine. According to the older widespread hypothesis, it means "borderland", while some more recent linguistic studies claim a different meaning: "homeland" or "region, country"."The Ukraine" used to be the usual form in English, but since the Declaration of Independence of Ukraine, "the Ukraine" has become less common in the English-speaking world, style-guides recommend not using the definite article.
"The Ukraine" now implies disregard for the country's sovereignty, according to U. S. ambassador William Taylor. The Ukrainian position is that the usage of "'The Ukraine' is incorrect both grammatically and politically." Neanderthal settlement in Ukraine is seen in the Molodova archaeological sites which include a mammoth bone dwelling. The territory is considered to be the location for the human domestication of the horse. Modern human settlement in Ukraine and its vicinity dates back to 32,000 BC, with evidence of the Gravettian culture in the Crimean Mountains. By 4,500 BC, the Neolithic Cucuteni–Trypillia culture flourished in wide areas of modern Ukraine including Trypillia and the entire Dnieper-Dniester region. During the Iron Age, the land was inhabited by Cimmerians and Sarmatians. Between 700 BC and 200 BC it was Scythia. Beginning in the sixth century BC, colonies of Ancient Greece, Ancient Rome and the Byzantine Empire, such as Tyras and Chersonesus, were founded on the northeastern shore of the Black Sea.
These colonies thrived well into the 6th century AD. The Goths stayed in the area but came under the sway of the Huns from the 370s AD. In the 7th century AD, the territory of eastern Ukraine was the centre of Old Great Bulgaria. At the end of the century, the majority of Bulgar tribes migrated in different directions, the Khazars took over much of the land. In the 5th and 6th centuries, the Antes were located in the territory of; the Antes were the ancestors of Ukrainians: White Croats, Polans, Dulebes and Tiverians. Migrations from Ukraine throughout the Balkans established many Southern Slavic nations. Northern migrations, reaching to the Ilmen l
Australia
Australia the Commonwealth of Australia, is a sovereign country comprising the mainland of the Australian continent, the island of Tasmania and numerous smaller islands. It is the world's sixth-largest country by total area; the neighbouring countries are Papua New Guinea and East Timor to the north. The population of 25 million is urbanised and concentrated on the eastern seaboard. Australia's capital is Canberra, its largest city is Sydney; the country's other major metropolitan areas are Melbourne, Brisbane and Adelaide. Australia was inhabited by indigenous Australians for about 60,000 years before the first British settlement in the late 18th century, it is documented. After the European exploration of the continent by Dutch explorers in 1606, who named it New Holland, Australia's eastern half was claimed by Great Britain in 1770 and settled through penal transportation to the colony of New South Wales from 26 January 1788, a date which became Australia's national day; the population grew in subsequent decades, by the 1850s most of the continent had been explored and an additional five self-governing crown colonies established.
On 1 January 1901, the six colonies federated. Australia has since maintained a stable liberal democratic political system that functions as a federal parliamentary constitutional monarchy, comprising six states and ten territories. Being the oldest and driest inhabited continent, with the least fertile soils, Australia has a landmass of 7,617,930 square kilometres. A megadiverse country, its size gives it a wide variety of landscapes, with deserts in the centre, tropical rainforests in the north-east and mountain ranges in the south-east. A gold rush began in Australia in the early 1850s, its population density, 2.8 inhabitants per square kilometre, remains among the lowest in the world. Australia generates its income from various sources including mining-related exports, telecommunications and manufacturing. Indigenous Australian rock art is the oldest and richest in the world, dating as far back as 60,000 years and spread across hundreds of thousands of sites. Australia is a developed country, with the world's 14th-largest economy.
It has a high-income economy, with the world's tenth-highest per capita income. It is a regional power, has the world's 13th-highest military expenditure. Australia has the world's ninth-largest immigrant population, with immigrants accounting for 26% of the population. Having the third-highest human development index and the eighth-highest ranked democracy globally, the country ranks in quality of life, education, economic freedom, civil liberties and political rights, with all its major cities faring well in global comparative livability surveys. Australia is a member of the United Nations, G20, Commonwealth of Nations, ANZUS, Organisation for Economic Co-operation and Development, World Trade Organization, Asia-Pacific Economic Cooperation, Pacific Islands Forum and the ASEAN Plus Six mechanism; the name Australia is derived from the Latin Terra Australis, a name used for a hypothetical continent in the Southern Hemisphere since ancient times. When Europeans first began visiting and mapping Australia in the 17th century, the name Terra Australis was applied to the new territories.
Until the early 19th century, Australia was best known as "New Holland", a name first applied by the Dutch explorer Abel Tasman in 1644 and subsequently anglicised. Terra Australis still saw occasional usage, such as in scientific texts; the name Australia was popularised by the explorer Matthew Flinders, who said it was "more agreeable to the ear, an assimilation to the names of the other great portions of the earth". The first time that Australia appears to have been used was in April 1817, when Governor Lachlan Macquarie acknowledged the receipt of Flinders' charts of Australia from Lord Bathurst. In December 1817, Macquarie recommended to the Colonial Office. In 1824, the Admiralty agreed that the continent should be known by that name; the first official published use of the new name came with the publication in 1830 of The Australia Directory by the Hydrographic Office. Colloquial names for Australia include "Oz" and "the Land Down Under". Other epithets include "the Great Southern Land", "the Lucky Country", "the Sunburnt Country", "the Wide Brown Land".
The latter two both derive from Dorothea Mackellar's 1908 poem "My Country". Human habitation of the Australian continent is estimated to have begun around 65,000 to 70,000 years ago, with the migration of people by land bridges and short sea-crossings from what is now Southeast Asia; these first inhabitants were the ancestors of modern Indigenous Australians. Aboriginal Australian culture is one of the oldest continual civilisations on earth. At the time of first European contact, most Indigenous Australians were hunter-gatherers with complex economies and societies. Recent archaeological finds suggest. Indigenous Australians have an oral culture with spiritual values based on reverence for the land and a belief in the Dreamtime; the Torres Strait Islanders, ethnically Melanesian, obtained their livelihood from seasonal horticulture and the resources of their reefs and seas. The northern coasts and waters of Australia were visited s
Wolf–Rayet star
Wolf–Rayet stars abbreviated as WR stars, are a rare heterogeneous set of stars with unusual spectra showing prominent broad emission lines of ionised helium and ionised nitrogen or carbon. The spectra indicate high surface enhancement of heavy elements, depletion of hydrogen, strong stellar winds, their surface temperatures range from 30,000 K to around 200,000 K, hotter than all other stars. Classic Wolf–Rayet stars are evolved, massive stars that have lost their outer hydrogen and are fusing helium or heavier elements in the core. A subset of the population I WR stars show hydrogen lines in their spectra and are known as WNh stars. A separate group of stars with WR spectra are the central stars of planetary nebulae, post asymptotic giant branch stars that were similar to the Sun while on the main sequence, but have now ceased fusion and shed their atmospheres to reveal a bare carbon-oxygen core. All Wolf–Rayet stars are luminous objects due to their high temperatures—thousands of times the bolometric luminosity of the Sun for the CSPNe, hundreds of thousands L☉ for the Population I WR stars, to over a million L☉ for the WNh stars—although not exceptionally bright visually since most of their radiation output is in the ultraviolet.
The naked-eye stars Gamma Velorum and Theta Muscae, as well as the most massive known star, R136a1 in 30 Doradus, are all Wolf–Rayet stars. In 1867, using the 40 cm Foucault telescope at the Paris Observatory, astronomers Charles Wolf and Georges Rayet discovered three stars in the constellation Cygnus that displayed broad emission bands on an otherwise continuous spectrum. Most stars only display absorption lines or bands in their spectra, as a result of overlying elements absorbing light energy at specific frequencies, so these were unusual objects; the nature of the emission bands in the spectra of a Wolf–Rayet star remained a mystery for several decades. Edward C. Pickering theorized that the lines were caused by an unusual state of hydrogen, it was found that this "Pickering series" of lines followed a pattern similar to the Balmer series, when half-integer quantum numbers were substituted, it was shown that the lines resulted from the presence of helium. Pickering noted similarities between Wolf–Rayet spectra and nebular spectra, this similarity led to the conclusion that some or all Wolf Rayet stars were the central stars of planetary nebulae.
By 1929, the width of the emission bands was being attributed to Doppler broadening, hence that the gas surrounding these stars must be moving with velocities of 300–2400 km/s along the line of sight. The conclusion was that a Wolf–Rayet star is continually ejecting gas into space, producing an expanding envelope of nebulous gas; the force ejecting the gas at the high velocities observed is radiation pressure. It was well known that many stars with Wolf Rayet type spectra were the central stars of planetary nebulae, but that many were not associated with an obvious planetary nebula or any visible nebulosity at all. In addition to helium, emission lines of carbon and nitrogen were identified in the spectra of Wolf–Rayet stars. In 1938, the International Astronomical Union classified the spectra of Wolf–Rayet stars into types WN and WC, depending on whether the spectrum was dominated by lines of nitrogen or carbon-oxygen respectively. In 1969, several CSPNe with strong OVI emissions lines were grouped under a new "OVI sequence", or just OVI type.
These were subsequently referred to as stars. Similar stars not associated with planetary nebulae were described shortly after and the WO classification was also adopted for population I WR stars; the understanding that certain late, sometimes not-so-late, WN stars with hydrogen lines in their spectra are at a different stage of evolution from hydrogen-free WR stars has led to the introduction of the term WNh to distinguish these stars from other WN stars. They were referred to as WNL stars, although there are late-type WN stars without hydrogen as well as WR stars with hydrogen as early as WN5. Wolf–Rayet stars were named on the basis of the strong broad emission lines in their spectra, identified with helium, carbon and oxygen, but with hydrogen lines weak or absent; the first system of classification split these into stars with dominant lines of ionised nitrogen and those with dominant lines of ionised carbon and sometimes oxygen, referred to as WN and WC respectively. The two classes WN and WC were further split into temperature sequences WN5-WN8 and WC6-WC8 based on the relative strengths of the 541.1nm HeII and 587.5 nm HeI lines.
Wolf–Rayet emission lines have a broadened absorption wing suggesting circumstellar material. A WO sequence has been separated from the WC sequence for hotter stars where emission of ionised oxygen dominates that of ionised carbon, although the actual proportions of those elements in the stars are to be comparable. WC and WO spectra are formally distinguished based on the absence of CIII emission. WC spectra generally lack the OVI lines that are strong in WO spectra; the WN spectral sequence was expanded to include WN2 - WN9, the definitions refined based on the relative strengths of the NIII lines at 463.4-464.1 nm and 531.4 nm, the NIV lines at 347.9-348.4 nm and 405.8 nm, the NV lines at 460.3 nm, 461.9 nm, 493.3-4
Campbell (lunar crater)
Campbell is a large lunar impact crater, located in the northern hemisphere on the far side of the Moon. It lies to the southwest of the walled plain D'Alembert, an larger formation. If Campbell were located on the near side of the Moon as seen from the Earth, it would form one of the largest visible craters, being larger than Schickard, it is bordered by several craters of note, with Wiener to the southwest, Von Neumann just to the south, Ley overlying the southeast rim, Pawsey to the west. This formation has been worn and eroded by a history of impacts, leaving a circular rim, an irregular ring of ridges and peaks. Multiple small craters lie along the inner wall, as well as across the interior floor; the most notable of these are Campbell X along the northeast inner rim and Campbell N near the southern inner wall. Much of the inner floor is covered by a multitude of lesser impacts; this area has a lower albedo than its surroundings, thus appearing dark. It stretches from the center of Campbell towards the western rim, has an irregular perimeter.
There is an unusual crater lying to the west of Von Neumann. This is formed by two or more overlapping craters, the most recent being Wiener F, a nearly hexagonal formation with a rugged interior. By convention these features are identified on lunar maps by placing the letter on the side of the crater midpoint, closest to Campbell
Spectroscopy
Spectroscopy is the study of the interaction between matter and electromagnetic radiation. Spectroscopy originated through the study of visible light dispersed according to its wavelength, by a prism; the concept was expanded to include any interaction with radiative energy as a function of its wavelength or frequency, predominantly in the electromagnetic spectrum, though matter waves and acoustic waves can be considered forms of radiative energy. Spectroscopic data are represented by an emission spectrum, a plot of the response of interest as a function of wavelength or frequency. Spectroscopy in the electromagnetic spectrum, is a fundamental exploratory tool in the fields of physics and astronomy, allowing the composition, physical structure and electronic structure of matter to be investigated at atomic scale, molecular scale, macro scale, over astronomical distances. Important applications arise from biomedical spectroscopy in the areas of tissue analysis and medical imaging. Spectroscopy and spectrography are terms used to refer to the measurement of radiation intensity as a function of wavelength and are used to describe experimental spectroscopic methods.
Spectral measurement devices are referred to as spectrometers, spectrophotometers, spectrographs or spectral analyzers. Daily observations of color can be related to spectroscopy. Neon lighting is a direct application of atomic spectroscopy. Neon and other noble gases have characteristic emission frequencies. Neon lamps use collision of electrons with the gas to excite these emissions. Inks and paints include chemical compounds selected for their spectral characteristics in order to generate specific colors and hues. A encountered molecular spectrum is that of nitrogen dioxide. Gaseous nitrogen dioxide has a characteristic red absorption feature, this gives air polluted with nitrogen dioxide a reddish-brown color. Rayleigh scattering is a spectroscopic scattering phenomenon. Spectroscopic studies were central to the development of quantum mechanics and included Max Planck's explanation of blackbody radiation, Albert Einstein's explanation of the photoelectric effect and Niels Bohr's explanation of atomic structure and spectra.
Spectroscopy is used in physical and analytical chemistry because atoms and molecules have unique spectra. As a result, these spectra can be used to detect and quantify information about the atoms and molecules. Spectroscopy is used in astronomy and remote sensing on Earth. Most research telescopes have spectrographs; the measured spectra are used to determine the chemical composition and physical properties of astronomical objects. One of the central concepts in spectroscopy is its corresponding resonant frequency. Resonances were first characterized in mechanical systems such as pendulums. Mechanical systems that vibrate or oscillate will experience large amplitude oscillations when they are driven at their resonant frequency. A plot of amplitude vs. excitation frequency will have a peak centered at the resonance frequency. This plot is one type of spectrum, with the peak referred to as a spectral line, most spectral lines have a similar appearance. In quantum mechanical systems, the analogous resonance is a coupling of two quantum mechanical stationary states of one system, such as an atom, via an oscillatory source of energy such as a photon.
The coupling of the two states is strongest when the energy of the source matches the energy difference between the two states. The energy of a photon is related to its frequency by E = h ν where h is Planck's constant, so a spectrum of the system response vs. photon frequency will peak at the resonant frequency or energy. Particles such as electrons and neutrons have a comparable relationship, the de Broglie relations, between their kinetic energy and their wavelength and frequency and therefore can excite resonant interactions. Spectra of atoms and molecules consist of a series of spectral lines, each one representing a resonance between two different quantum states; the explanation of these series, the spectral patterns associated with them, were one of the experimental enigmas that drove the development and acceptance of quantum mechanics. The hydrogen spectral series in particular was first explained by the Rutherford-Bohr quantum model of the hydrogen atom. In some cases spectral lines are well separated and distinguishable, but spectral lines can overlap and appear to be a single transition if the density of energy states is high enough.
Named series of lines include the principal, sharp and fundamental series. Spectroscopy is a sufficiently broad field that many sub-disciplines exist, each with numerous implementations of specific spectroscopic techniques; the various implementations and techniques can be classified in several ways. The types of spectroscopy are distinguished by the type of radiative energy involved in the interaction. In many applications, the spectrum is determined by measuring changes in the intensity or frequency of this energy; the types of radiative energy studied include: Electromagnetic radiation was the first source of energy used for spectroscopic studies. Techniques that employ electromagnetic radiation are classified by the wavelength region of the spectrum and include microwave, terahe
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