1.
Stratospheric Observatory for Infrared Astronomy
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The Stratospheric Observatory for Infrared Astronomy is an 80/20 joint project of NASA and the German Aerospace Center to construct and maintain an airborne observatory. NASA awarded the contract for the development of the aircraft, operation of the observatory, the DSI manages the German parts of the project which are primarily science and telescope related. SOFIAs telescope saw first light on May 26,2010, SOFIA is the successor to the Kuiper Airborne Observatory. This telescope is designed for infrared astronomy observations in the stratosphere at altitudes of about 12 kilometres, SOFIAs flight capability allows it to rise above almost all of the water vapor in the Earths atmosphere, which blocks some infrared wavelengths from reaching the ground. At the aircrafts cruising altitude, 85% of the infrared range will be available. The aircraft can travel to almost any point on the Earths surface. Once ready for use, observing flights were expected to be three or four nights a week. SOFIA uses a 2.5 m reflector telescope, which has an oversized,2.7 m diameter primary mirror, the optical system uses a Cassegrain reflector design with a parabolic primary mirror and a remotely configurable hyperbolic secondary. In order to fit the telescope into the fuselage, the primary is shaped to an f-number as low as 1.3, a flat, tertiary, dichroic mirror is used to deflect the infrared part of the beam to the Nasmyth focus where it can be analyzed. An optical mirror located behind the mirror is used for a camera guidance system. 3–1.1 μm. The main instruments are the FLITECAM, an infrared camera covering 1–5 μm, FORCAST, covering the mid-infrared range of 5–40 μm, and HAWC. The other four instruments include an optical photometer and infrared spectrometers with various spectral ranges, sOFIA’s telescope is by far the largest ever to be placed in an aircraft. For each mission one interchangeable science instrument will be attached to the telescope, two groups of general purpose instruments are available. In addition an investigator can also design and build a special purpose instrument, the open cavity housing the telescope will be exposed to high-speed turbulent winds. In addition, the vibrations and motions of the aircraft introduce observing difficulties, the telescope was designed to be very lightweight, with a honeycomb shape milled into the back of the mirror and polymer composite material used for the telescope assembly. The mount includes a system of bearings in pressurized oil to isolate the instrument from vibration, tracking is achieved through a system of gyroscopes, high speed cameras, and magnetic torque motors to compensate for motion, including vibrations from airflow and the aircraft engines. The telescope cabin must be cooled prior to aircraft takeoff to ensure the telescope matches the temperature to prevent thermally induced shape changes. Prior to landing the compartment is flooded with gas to prevent condensation of moisture on the chilled optics
2.
Telescope
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A telescope is an optical instrument that aids in the observation of remote objects by collecting electromagnetic radiation. The first known practical telescopes were invented in the Netherlands at the beginning of the 1600s and they found use in both terrestrial applications and astronomy. Within a few decades, the telescope was invented, which used mirrors to collect. In the 20th century many new types of telescopes were invented, including radio telescopes in the 1930s, the word telescope now refers to a wide range of instruments capable of detecting different regions of the electromagnetic spectrum, and in some cases other types of detectors. The word telescope was coined in 1611 by the Greek mathematician Giovanni Demisiani for one of Galileo Galileis instruments presented at a banquet at the Accademia dei Lincei, in the Starry Messenger, Galileo had used the term perspicillum. The earliest recorded working telescopes were the telescopes that appeared in the Netherlands in 1608. Their development is credited to three individuals, Hans Lippershey and Zacharias Janssen, who were spectacle makers in Middelburg, Galileo heard about the Dutch telescope in June 1609, built his own within a month, and improved upon the design in the following year. Also in 1609, Thomas Harriot became the first person known to point a telescope skyward in order to make observations of a celestial object. The idea that the objective, or light-gathering element, could be a mirror instead of a lens was being investigated soon after the invention of the refracting telescope. The potential advantages of using parabolic mirrors—reduction of spherical aberration and no chromatic aberration—led to many proposed designs, in 1668, Isaac Newton built the first practical reflecting telescope, of a design which now bears his name, the Newtonian reflector. The invention of the lens in 1733 partially corrected color aberrations present in the simple lens and enabled the construction of shorter. The largest reflecting telescopes currently have objectives larger than 10 m, the 20th century also saw the development of telescopes that worked in a wide range of wavelengths from radio to gamma-rays. The first purpose built radio telescope went into operation in 1937, since then, a tremendous variety of complex astronomical instruments have been developed. The name telescope covers a range of instruments. Most detect electromagnetic radiation, but there are differences in how astronomers must go about collecting light in different frequency bands. The near-infrared can be collected much like light, however in the far-infrared and submillimetre range. For example, the James Clerk Maxwell Telescope observes from wavelengths from 3 μm to 2000 μm, on the other hand, the Spitzer Space Telescope, observing from about 3 μm to 180 μm uses a mirror. Also using reflecting optics, the Hubble Space Telescope with Wide Field Camera 3 can observe in the range from about 0.2 μm to 1.7 μm
3.
Infrared
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It extends from the nominal red edge of the visible spectrum at 700 nanometers, to 1000000 nm. Most of the radiation emitted by objects near room temperature is infrared. Like all EMR, IR carries radiant energy, and behaves both like a wave and like its quantum particle, the photon, slightly more than half of the total energy from the Sun was eventually found to arrive on Earth in the form of infrared. The balance between absorbed and emitted infrared radiation has an effect on Earths climate. Infrared radiation is emitted or absorbed by molecules when they change their rotational-vibrational movements and it excites vibrational modes in a molecule through a change in the dipole moment, making it a useful frequency range for study of these energy states for molecules of the proper symmetry. Infrared spectroscopy examines absorption and transmission of photons in the infrared range, Infrared radiation is used in industrial, scientific, and medical applications. Night-vision devices using active near-infrared illumination allow people or animals to be observed without the observer being detected, Infrared thermal-imaging cameras are used to detect heat loss in insulated systems, to observe changing blood flow in the skin, and to detect overheating of electrical apparatuses. Thermal-infrared imaging is used extensively for military and civilian purposes, military applications include target acquisition, surveillance, night vision, homing, and tracking. Humans at normal body temperature radiate chiefly at wavelengths around 10 μm, Infrared radiation extends from the nominal red edge of the visible spectrum at 700 nanometers to 1 mm. This range of wavelengths corresponds to a range of approximately 430 THz down to 300 GHz. Below infrared is the portion of the electromagnetic spectrum. Sunlight, at a temperature of 5,780 kelvins, is composed of near thermal-spectrum radiation that is slightly more than half infrared. At zenith, sunlight provides an irradiance of just over 1 kilowatt per square meter at sea level, of this energy,527 watts is infrared radiation,445 watts is visible light, and 32 watts is ultraviolet radiation. Nearly all the radiation in sunlight is near infrared, shorter than 4 micrometers. On the surface of Earth, at far lower temperatures than the surface of the Sun, almost all thermal radiation consists of infrared in mid-infrared region, much longer than in sunlight. Of these natural thermal radiation processes only lightning and natural fires are hot enough to produce much visible energy, thermal infrared radiation also has a maximum emission wavelength, which is inversely proportional to the absolute temperature of object, in accordance with Wiens displacement law. Therefore, the band is often subdivided into smaller sections. Due to the nature of the blackbody radiation curves, typical hot objects, such as exhaust pipes, the three regions are used for observation of different temperature ranges, and hence different environments in space
4.
Electromagnetic spectrum
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The electromagnetic spectrum is the collective term for all known frequencies and their linked wavelengths of the known photons. The electromagnetic spectrum of an object has a different meaning, and is instead the characteristic distribution of radiation emitted or absorbed by that particular object. Visible light lies toward the end, with wavelengths from 400 to 700 nanometres. The limit for long wavelengths is the size of the universe itself, until the middle of the 20th century it was believed by most physicists that this spectrum was infinite and continuous. Nearly all types of radiation can be used for spectroscopy, to study. Other technological uses are described under electromagnetic radiation, for most of history, visible light was the only known part of the electromagnetic spectrum. The ancient Greeks recognized that light traveled in straight lines and studied some of its properties, the study of light continued, and during the 16th and 17th centuries conflicting theories regarded light as either a wave or a particle. The first discovery of electromagnetic radiation other than visible light came in 1800 and he was studying the temperature of different colors by moving a thermometer through light split by a prism. He noticed that the highest temperature was beyond red and he theorized that this temperature change was due to calorific rays that were a type of light ray that could not be seen. The next year, Johann Ritter, working at the end of the spectrum. These behaved similarly to visible light rays, but were beyond them in the spectrum. They were later renamed ultraviolet radiation, during the 1860s James Maxwell developed four partial differential equations for the electromagnetic field. Two of these equations predicted the possibility of, and behavior of, analyzing the speed of these theoretical waves, Maxwell realized that they must travel at a speed that was about the known speed of light. This startling coincidence in value led Maxwell to make the inference that light itself is a type of electromagnetic wave, maxwells equations predicted an infinite number of frequencies of electromagnetic waves, all traveling at the speed of light. This was the first indication of the existence of the electromagnetic spectrum. Maxwells predicted waves included waves at very low compared to infrared. Hertz found the waves and was able to infer that they traveled at the speed of light, Hertz also demonstrated that the new radiation could be both reflected and refracted by various dielectric media, in the same manner as light. For example, Hertz was able to focus the waves using a lens made of tree resin, in a later experiment, Hertz similarly produced and measured the properties of microwaves
5.
Absolute zero
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Absolute zero is the lower limit of the thermodynamic temperature scale, a state at which the enthalpy and entropy of a cooled ideal gas reaches its minimum value, taken as 0. The corresponding Kelvin and Rankine temperature scales set their zero points at absolute zero by definition, in the quantum-mechanical description, matter at absolute zero is in its ground state, the point of lowest internal energy. And a system at absolute zero still possesses quantum mechanical zero-point energy, the kinetic energy of the ground state cannot be removed. Scientists and technologists routinely achieve temperatures close to zero, where matter exhibits quantum effects such as superconductivity and superfluidity. At temperatures near 0 K, nearly all molecular motion ceases and ΔS =0 for any adiabatic process, in such a circumstance, pure substances can form perfect crystals as T →0. Max Plancks strong form of the law of thermodynamics states the entropy of a perfect crystal vanishes at absolute zero. The Nernst postulate identifies the isotherm T =0 as coincident with the adiabat S =0, although other isotherms, as no two adiabats intersect, no other adiabat can intersect the T =0 isotherm. Consequently no adiabatic process initiated at nonzero temperature can lead to zero temperature, a perfect crystal is one in which the internal lattice structure extends uninterrupted in all directions. The perfect order can be represented by translational symmetry along three axes, every lattice element of the structure is in its proper place, whether it is a single atom or a molecular grouping. For substances that exist in two crystalline forms, such as diamond and graphite for carbon, there is a kind of chemical degeneracy. The question remains whether both can have zero entropy at T =0 even though each is perfectly ordered, using the Debye model, the specific heat and entropy of a pure crystal are proportional to T3, while the enthalpy and chemical potential are proportional to T4. These quantities drop toward their T =0 limiting values and approach with zero slopes, for the specific heats at least, the limiting value itself is definitely zero, as borne out by experiments to below 10 K. Even the less detailed Einstein model shows this curious drop in specific heats, in fact, all specific heats vanish at absolute zero, not just those of crystals. Likewise for the coefficient of thermal expansion, maxwells relations show that various other quantities also vanish. Since the relation between changes in Gibbs free energy, the enthalpy and the entropy is Δ G = Δ H − T Δ S thus, as T decreases, ΔG and ΔH approach each other. Experimentally, it is found that all spontaneous processes result in a decrease in G as they proceed toward equilibrium, if ΔS and/or T are small, the condition ΔG <0 may imply that ΔH <0, which would indicate an exothermic reaction. However, this is not required, endothermic reactions can proceed spontaneously if the TΔS term is large enough, moreover, the slopes of the derivatives of ΔG and ΔH converge and are equal to zero at T =0. e. An actual process is the most exothermic one, one model that estimates the properties of an electron gas at absolute zero in metals is the Fermi gas
6.
Electromagnetic radiation
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In physics, electromagnetic radiation refers to the waves of the electromagnetic field, propagating through space carrying electromagnetic radiant energy. It includes radio waves, microwaves, infrared, light, ultraviolet, X-, classically, electromagnetic radiation consists of electromagnetic waves, which are synchronized oscillations of electric and magnetic fields that propagate at the speed of light through a vacuum. The oscillations of the two fields are perpendicular to other and perpendicular to the direction of energy and wave propagation. The wavefront of electromagnetic waves emitted from a point source is a sphere, the position of an electromagnetic wave within the electromagnetic spectrum can be characterized by either its frequency of oscillation or its wavelength. Electromagnetic waves are produced whenever charged particles are accelerated, and these waves can interact with other charged particles. EM waves carry energy, momentum and angular momentum away from their source particle, quanta of EM waves are called photons, whose rest mass is zero, but whose energy, or equivalent total mass, is not zero so they are still affected by gravity. Thus, EMR is sometimes referred to as the far field, in this language, the near field refers to EM fields near the charges and current that directly produced them, specifically, electromagnetic induction and electrostatic induction phenomena. In the quantum theory of electromagnetism, EMR consists of photons, quantum effects provide additional sources of EMR, such as the transition of electrons to lower energy levels in an atom and black-body radiation. The energy of a photon is quantized and is greater for photons of higher frequency. This relationship is given by Plancks equation E = hν, where E is the energy per photon, ν is the frequency of the photon, a single gamma ray photon, for example, might carry ~100,000 times the energy of a single photon of visible light. The effects of EMR upon chemical compounds and biological organisms depend both upon the power and its frequency. EMR of visible or lower frequencies is called non-ionizing radiation, because its photons do not individually have enough energy to ionize atoms or molecules, the effects of these radiations on chemical systems and living tissue are caused primarily by heating effects from the combined energy transfer of many photons. In contrast, high ultraviolet, X-rays and gamma rays are called ionizing radiation since individual photons of high frequency have enough energy to ionize molecules or break chemical bonds. These radiations have the ability to cause chemical reactions and damage living cells beyond that resulting from simple heating, Maxwell derived a wave form of the electric and magnetic equations, thus uncovering the wave-like nature of electric and magnetic fields and their symmetry. Because the speed of EM waves predicted by the wave equation coincided with the speed of light. Maxwell’s equations were confirmed by Heinrich Hertz through experiments with radio waves, according to Maxwells equations, a spatially varying electric field is always associated with a magnetic field that changes over time. Likewise, a varying magnetic field is associated with specific changes over time in the electric field. In an electromagnetic wave, the changes in the field are always accompanied by a wave in the magnetic field in one direction
7.
Gamma ray
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Gamma ray, denoted by the lower-case Greek letter gamma, is penetrating electromagnetic radiation of a kind arising from the radioactive decay of atomic nuclei. It consists of photons in the highest observed range of photon energy, paul Villard, a French chemist and physicist, discovered gamma radiation in 1900 while studying radiation emitted by radium. In 1903, Ernest Rutherford named this radiation gamma rays, Rutherford had previously discovered two other types of radioactive decay, which he named alpha and beta rays. Gamma rays are able to ionize atoms, and are thus biologically hazardous. The decay of a nucleus from a high energy state to a lower energy state. Natural sources of gamma rays on Earth are observed in the decay of radionuclides. There are rare terrestrial natural sources, such as lightning strikes and terrestrial gamma-ray flashes, However, a large fraction of such astronomical gamma rays are screened by Earths atmosphere and can only be detected by spacecraft. Gamma rays typically have frequencies above 10 exahertz, and therefore have energies above 100 keV and wavelengths less than 10 picometers, However, this is not a strict definition, but rather only a rule-of-thumb description for natural processes. Electromagnetic radiation from radioactive decay of nuclei is referred to as gamma rays no matter its energy. This radiation commonly has energy of a few hundred keV, in astronomy, gamma rays are defined by their energy, and no production process needs to be specified. The energies of gamma rays from astronomical sources range to over 10 TeV, a notable example is the extremely powerful bursts of high-energy radiation referred to as long duration gamma-ray bursts, of energies higher than can be produced by radioactive decay. These bursts of gamma rays are thought to be due to the collapse of stars called hypernovae, the first gamma ray source to be discovered historically was the radioactive decay process called gamma decay. In this type of decay, a nucleus emits a gamma ray almost immediately upon formation. Paul Villard, a French chemist and physicist, discovered gamma radiation in 1900, However, Villard did not consider naming them as a different fundamental type. Rutherford also noted that gamma rays were not deflected by a field, another property making them unlike alpha. Gamma rays were first thought to be particles with mass, like alpha, Rutherford initially believed that they might be extremely fast beta particles, but their failure to be deflected by a magnetic field indicated that they had no charge. In 1914, gamma rays were observed to be reflected from crystal surfaces, Rutherford and his coworker Edward Andrade measured the wavelengths of gamma rays from radium, and found that they were similar to X-rays, but with shorter wavelengths and higher frequency. This was eventually recognized as giving them more energy per photon
8.
X-ray
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X-radiation is a form of electromagnetic radiation. Most X-rays have a wavelength ranging from 0.01 to 10 nanometers, corresponding to frequencies in the range 30 petahertz to 30 exahertz, X-ray wavelengths are shorter than those of UV rays and typically longer than those of gamma rays. Spelling of X-ray in the English language includes the variants x-ray, xray, X-rays with high photon energies are called hard X-rays, while those with lower energy are called soft X-rays. Due to their ability, hard X-rays are widely used to image the inside of objects, e. g. in medical radiography. The term X-ray is metonymically used to refer to an image produced using this method. Since the wavelengths of hard X-rays are similar to the size of atoms they are useful for determining crystal structures by X-ray crystallography. By contrast, soft X-rays are easily absorbed in air, the length of 600 eV X-rays in water is less than 1 micrometer. There is no consensus for a definition distinguishing between X-rays and gamma rays, one common practice is to distinguish between the two types of radiation based on their source, X-rays are emitted by electrons, while gamma rays are emitted by the atomic nucleus. This definition has problems, other processes also can generate these high-energy photons. One common alternative is to distinguish X- and gamma radiation on the basis of wavelength, with radiation shorter than some arbitrary wavelength, such as 10−11 m and this criterion assigns a photon to an unambiguous category, but is only possible if wavelength is known. Occasionally, one term or the other is used in specific contexts due to precedent, based on measurement technique. Thus, gamma-rays generated for medical and industrial uses, for radiotherapy, in the ranges of 6–20 MeV. X-ray photons carry enough energy to ionize atoms and disrupt molecular bonds and this makes it a type of ionizing radiation, and therefore harmful to living tissue. A very high radiation dose over a period of time causes radiation sickness. In medical imaging this increased risk is generally greatly outweighed by the benefits of the examination. The ionizing capability of X-rays can be utilized in treatment to kill malignant cells using radiation therapy. It is also used for material characterization using X-ray spectroscopy, hard X-rays can traverse relatively thick objects without being much absorbed or scattered. For this reason, X-rays are widely used to image the inside of visually opaque objects, the most often seen applications are in medical radiography and airport security scanners, but similar techniques are also important in industry and research
9.
Ultra-violet
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Ultraviolet is an electromagnetic radiation with a wavelength from 10 nm to 400 nm, shorter than that of visible light but longer than X-rays. UV radiation constitutes about 10% of the light output of the Sun. It is also produced by electric arcs and specialized lights, such as lamps, tanning lamps. Consequently, the effects of UV are greater than simple heating effects. Suntan, freckling and sunburn are familiar effects of over-exposure, along with risk of skin cancer. Living things on dry land would be damaged by ultraviolet radiation from the Sun if most of it were not filtered out by the Earths atmosphere. More-energetic, shorter-wavelength extreme UV below 121 nm ionizes air so strongly that it is absorbed before it reaches the ground, Ultraviolet is also responsible for the formation of bone-strengthening vitamin D in most land vertebrates, including humans. The UV spectrum thus has both beneficial and harmful to human health. Ultraviolet rays are invisible to most humans, the lens in a human eye ordinarily filters out UVB frequencies or higher, and humans lack color receptor adaptations for ultraviolet rays. Under some conditions, children and young adults can see ultraviolet down to wavelengths of about 310 nm, near-UV radiation is visible to some insects, mammals, and birds. Small birds have a fourth color receptor for ultraviolet rays, this gives birds true UV vision, reindeer use near-UV radiation to see polar bears, who are poorly visible in regular light because they blend in with the snow. UV also allows mammals to see urine trails, which is helpful for animals to find food in the wild. The males and females of some species look identical to the human eye. Ultraviolet means beyond violet, violet being the color of the highest frequencies of visible light, Ultraviolet has a higher frequency than violet light. He called them oxidizing rays to emphasize chemical reactivity and to them from heat rays. The terms chemical and heat rays were eventually dropped in favour of ultraviolet and infrared radiation, in 1878 the effect of short-wavelength light on sterilizing bacteria was discovered. By 1903 it was known the most effective wavelengths were around 250 nm, in 1960, the effect of ultraviolet radiation on DNA was established. The discovery of the ultraviolet radiation below 200 nm, named vacuum ultraviolet because it is absorbed by air, was made in 1893 by the German physicist Victor Schumann
10.
Light
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Light is electromagnetic radiation within a certain portion of the electromagnetic spectrum. The word usually refers to light, which is visible to the human eye and is responsible for the sense of sight. Visible light is defined as having wavelengths in the range of 400–700 nanometres, or 4.00 × 10−7 to 7.00 × 10−7 m. This wavelength means a range of roughly 430–750 terahertz. The main source of light on Earth is the Sun, sunlight provides the energy that green plants use to create sugars mostly in the form of starches, which release energy into the living things that digest them. This process of photosynthesis provides virtually all the used by living things. Historically, another important source of light for humans has been fire, with the development of electric lights and power systems, electric lighting has effectively replaced firelight. Some species of animals generate their own light, a process called bioluminescence, for example, fireflies use light to locate mates, and vampire squids use it to hide themselves from prey. Visible light, as all types of electromagnetic radiation, is experimentally found to always move at this speed in a vacuum. In physics, the term sometimes refers to electromagnetic radiation of any wavelength. In this sense, gamma rays, X-rays, microwaves and radio waves are also light, like all types of light, visible light is emitted and absorbed in tiny packets called photons and exhibits properties of both waves and particles. This property is referred to as the wave–particle duality, the study of light, known as optics, is an important research area in modern physics. Generally, EM radiation, or EMR, is classified by wavelength into radio, microwave, infrared, 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 the amount of energy per quantum it carries. There exist animals that are sensitive to various types of infrared, infrared sensing in snakes depends on a kind of natural thermal imaging, in which tiny packets of cellular water are raised in temperature by 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 nanometers and the internal lens below 400. Furthermore, the rods and cones located in the retina of the eye cannot detect the very short ultraviolet wavelengths and are in fact damaged by ultraviolet. Many animals with eyes that do not require lenses are able to detect ultraviolet, by quantum photon-absorption mechanisms, various sources define visible light as narrowly as 420 to 680 to as broadly as 380 to 800 nm
11.
William Herschel
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Frederick William Herschel, KH, FRS was a British astronomer and composer of German origin, and brother of fellow astronomer Caroline Herschel, with whom he worked. Born in the Electorate of Hanover, Herschel followed his father into the Military Band of Hanover, Herschel constructed his first large telescope in 1774, after which he spent nine years carrying out sky surveys to investigate double stars. The resolving power of the Herschel telescopes revealed that the nebulae in the Messier catalogue were clusters of stars, Herschel published catalogues of nebulae in 1802 and in 1820. In the course of an observation on 13 March 1781, he realized that one celestial body he had observed was not a star and this was the first planet to be discovered since antiquity and Herschel became famous overnight. As a result of this discovery, George III appointed him Court Astronomer and he was elected as a Fellow of the Royal Society and grants were provided for the construction of new telescopes. Herschel pioneered the use of astronomical spectrophotometry as a tool, using prisms. Other work included a determination of the rotation period of Mars, the discovery that the Martian polar caps vary seasonally. In addition, Herschel discovered infrared radiation, Herschel was made a Knight of the Royal Guelphic Order in 1816. He was the first President of the Royal Astronomical Society when it was founded in 1820 and he died in August 1822, and his work was continued by his only son, John Herschel. Herschel was born in the Electorate of Hanover in Germany, then part of the Holy Roman Empire and his father was an oboist in the Hanover Military Band. In 1755 the Hanoverian Guards regiment, in whose band Wilhelm, at the time the crowns of Great Britain and Hanover were united under King George II. As the threat of war with France loomed, the Hanoverian Guards were recalled from England to defend Hanover, after they were defeated at the Battle of Hastenbeck, Herschels father Isaak sent his two sons to seek refuge in England in late 1757. Although his older brother Jakob had received his dismissal from the Hanoverian Guards, Wilhelm, nineteen years old at this time, was a quick student of the English language. In England he went by the English rendition of his name, in addition to the oboe, he played the violin and harpsichord and later the organ. He composed numerous works, including 24 symphonies and many concertos. Six of his symphonies were recorded in April 2002 by the London Mozart Players, Herschel moved to Sunderland in 1761 when Charles Avison immediately engaged him as first violin and soloist for his Newcastle orchestra, where he played for one season. In ‘Sunderland in the County of Durh, apprill 20th 1761’ he wrote his Symphony No.8 in C Minor. He was head of the Durham Militia band 1760–61 and visited the home of Sir Ralph Milbanke at Halnaby Hall in 1760, after Newcastle he moved to Leeds and Halifax where he was the first organist at St John the Baptist church
12.
Samuel Pierpont Langley
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Samuel Pierpont Langley was an American astronomer, physicist, inventor of the bolometer and pioneer of aviation. He was born in Roxbury, Boston on 22 August 1834, Langley was the founder of the Smithsonian Astrophysical Observatory. In 1888 Langley was elected a member of the American Antiquarian Society, by then, the department was in disarray – equipment was broken, there was no library and the building needed repairs. Through the friendship and aid of William Thaw, a Pittsburgh industrial leader, Langley was able to improve the observatory equipment, one of the new instruments was a small transit telescope used to observe the position of the stars as they cross the celestial meridian. He raised money for the department in large part by distributing standard time to cities, up until then, correct time had only occasionally been sent from American observatories for public use. Clocks were manually wound in those days and time tended to be imprecise, exact time had not been especially necessary. It was enough to know that at noon the sun was directly above the head, all that until railroad tracks were installed. As railroads became operational, that unpredictability of time became dangerous, trains ran by a published schedule, but the scheduling was chaotic. If the watches of an engineer and a switch operator differed by even a minute or two, it could mean disaster, two trains could be on the same track at the same time and crash. Using astronomical observations obtained from the new telescope, Langley devised a time standard – including time zones – that became known as the Allegheny Time System. Initially he broadcast time signals to Allegheny city business and the Pennsylvania Railroad, eventually, twice a day, the Allegheny time signals broadcast the correct time via 4713 miles of telegraph lines to all railroads in the US and Canada. Langley used the money from the railroads to finance the observatory, from about 1868, revenues from the Allegheny Time continued to fund the observatory until the US Naval Observatory provided the signals for free in 1883. Once funding was secure, Langley devoted his time at the Observatory initially in researching the sun and he used his draftsman skills to produce hundreds of drawings of solar phenomena, many of which were the first the world had seen. His 1873 remarkably detailed illustration of a sun spot, observed while using the observatorys 13-inch Fitz-Clark refractor became a classic and it is featured on page 21 of his book, The New Astronomy, but was also widely reprinted – in the Americas as well as throughout Europe. In 1886, Langley received the inaugural Henry Draper Medal from the National Academy of Sciences for his contributions to solar physics, in 1898, Langley received the Prix Jules Janssen, the highest award of the Société astronomique de France. Langley attempted to make a working piloted heavier-than-air aircraft and his models flew, but his two attempts at piloted flight were not successful. Langley began experimenting with rubber-band powered models and gliders in 1887 and he built a rotating arm and made larger flying models powered by miniature steam engines. It flew on trial over two hundred yards, and drowned itself in the waters of the Potomac, which was cause of great mirth, Langley took it coolly enough and said to me that, though he would never live till then, I should see the aeroplane established
13.
Bolometer
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A bolometer is a device for measuring the power of incident electromagnetic radiation via the heating of a material with a temperature-dependent electrical resistance. It was invented in 1878 by the American astronomer Samuel Pierpont Langley, a bolometer consists of an absorptive element, such as a thin layer of metal, connected to a thermal reservoir through a thermal link. The result is that any radiation impinging on the absorptive element raises its temperature above that of the reservoir – the greater the absorbed power, the higher the temperature. The temperature change can be measured directly with an attached resistive thermometer, metal bolometers usually work without cooling. They are produced from thin foils or metal films, today, most bolometers use semiconductor or superconductor absorptive elements rather than metals. These devices can be operated at cryogenic temperatures, enabling significantly greater sensitivity, bolometers are directly sensitive to the energy left inside the absorber. The most sensitive bolometers are very slow to reset, on the other hand, compared to more conventional particle detectors, they are extremely efficient in energy resolution and in sensitivity. They are also known as thermal detectors, the first bolometer used by Langley consisted of two platinum strips covered with lampblack. One strip was shielded from radiation and one exposed to it, the strips formed two branches of a Wheatstone bridge which was fitted with a sensitive galvanometer and connected to a battery. Electromagnetic radiation falling on the strip would heat it and change its resistance. By 1880, Langleys bolometer was refined enough to detect radiation from a cow a quarter of a mile away. This radiant-heat detector is sensitive to differences in temperature of one hundred-thousandth of a degree Celsius and this instrument enabled him to thermally detect across a broad spectrum, noting all the chief Fraunhofer lines. He also discovered new atomic and molecular absorption lines in the infrared portion of the electromagnetic spectrum. Nikola Tesla personally asked Dr. Langley if he could use his bolometer for his power transmission experiments in 1892, thanks to that first use, he succeeded in making the first demonstration between West Point and his laboratory on Houston Street. While bolometers can be used to measure radiation of any frequency, for sub-millimeter wavelengths, bolometers are among the most sensitive available detectors, and are therefore used for astronomy at these wavelengths. To achieve the best sensitivity, they must be cooled to a fraction of a degree above absolute zero, notable examples of bolometers employed in submillimeter astronomy include the Herschel Space Observatory, the James Clerk Maxwell Telescope, and the Stratospheric Observatory for Infrared Astronomy. The term bolometer is also used in physics to designate an unconventional particle detector. They use the principle described above
14.
Tasimeter
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The tasimeter, or Microtasimeter, or measurer of infinitesimal pressure, is a device designed by Thomas Edison to measure infrared radiation. To satisfy those needs Edison devised a microtasimeter employing a carbon button, the value of the instrument lies in its ability to detect small variations of temperature. During the total eclipse of the sun in 1878, it demonstrated the existence of heat in the corona. It is also of service in ascertaining the relative expansion of substances due to a rise of temperature, the functional parts are represented in the partial cross section, which shows its construction and mode of operation. The substance whose expansion is to be measured is shown at A and it is firmly clamped at B, its lower end fitting into a slot in the metal plate, M, which rests upon the carbon-button. The latter is in a circuit, which includes also a delicate galvanometer. Any variation in the length of the rod changes the pressure upon the carbon and this causes a deflection of the galvanometer-needle—a movement in one direction denoting expansion of A, while an opposite motion signifies contraction. To avoid any deflection which might arise from change in strength of battery, the screw works a second screw, causing the rod to ascend or descend, and the exact distance through which the rod moves is indicated by the needle, N, on the dial. The instrument can also be used to measure changes in the humidity of the atmosphere. In this case the strip of vulcanite is replaced by one of gelatine, the basic problem seemed to be to keep the burner, or bulb, from being consumed by preventing it from overheating. Edison thought he would be able to solve this by fashioning a microtasimeter-like device to control the current and he boldly announced that he would invent a safe, mild, and inexpensive electric light that would replace the gaslight. Eclipse Vicissitudes, Thomas Edison and the Chickens, J. Donald Fernie, Edison the scientist, John A. Eddy, Applied Optics
15.
Corona
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A corona is an aura of plasma that surrounds the sun and other stars. The Suns corona extends millions of kilometres into space and is most easily seen during a solar eclipse. The word corona is a Latin word meaning crown, from the Ancient Greek κορώνη, the high temperature of the Suns corona gives it unusual spectral features, which led some in the 19th century to suggest that it contained a previously unknown element, coronium. Instead, these features have since been explained by highly ionized iron. Bengt Edlén, following the work of Grotrian, first identified the coronal spectral lines in 1940 as transitions from low-lying metastable levels of the configuration of highly ionised metals. These high stages of ionisation indicate a temperature in excess of 1,000,000 kelvins. Light from the corona comes from three sources, from the same volume of space. The suns corona is much hotter than the surface of the Sun. The corona is 10−12 times as dense as the photosphere, the corona is separated from the photosphere by the relatively shallow chromosphere. The exact mechanism by which the corona is heated is still the subject of some debate, the outer edges of the Suns corona are constantly being transported away due to open magnetic flux and hence generating the solar wind. The corona is not always evenly distributed across the surface of the sun, during periods of quiet, the corona is more or less confined to the equatorial regions, with coronal holes covering the polar regions. However, during the Suns active periods, the corona is evenly distributed over the equatorial and polar regions, the solar cycle spans approximately 11 years, from solar minimum to the following minimum. Associated with sunspots are coronal loops, loops of magnetic flux, the magnetic flux pushes the hotter photosphere aside, exposing the cooler plasma below, thus creating the relatively dark sun spots. The astronomers usually distinguish several regions, as described below, active regions are ensembles of loop structures connecting points of opposite magnetic polarity in the photosphere, the so-called coronal loops. They generally distribute in two zones of activity, which are parallel to the solar equator, the average temperature is between two and four million kelvins, while the density goes from 109 to 1010 particle per cm3. If flares are very violent, they can also perturb the photosphere, on the contrary, quiescent prominences are large, cool dense structures which are observed as dark, snake-like Hα ribbons on the solar disc. Their temperature is about 5000–8000 K, and so they are considered as chromospheric features. In 2013, images from the High Resolution Coronal Imager revealed never-before-seen magnetic braids of plasma within the layers of these active regions
16.
Liquid nitrogen
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Liquid nitrogen is nitrogen in a liquid state at an extremely low temperature. It is a clear liquid with a density of 0.807 g/ml at its boiling point. Nitrogen was first liquefied at the Jagiellonian University on 15 April 1883 by Polish physicists, Zygmunt Wróblewski and it is produced industrially by fractional distillation of liquid air. Liquid nitrogen is often referred to by the abbreviation, LN2 or LIN or LN and has the UN number 1977, Liquid nitrogen is a diatomic liquid, which means that the diatomic character of the covalent N bonding in N2 gas is retained after liquefaction. Liquid nitrogen is a fluid that can cause rapid freezing on contact with living tissue. When appropriately insulated from ambient heat, liquid nitrogen can be stored and transported, the temperature is held constant at 77 K by slow boiling of the liquid, resulting in the evolution of nitrogen gas. Depending on the size and design, the time of vacuum flasks ranges from a few hours to a few weeks. The development of pressurised super-insulated vacuum vessels has enabled liquefied nitrogen to be stored and transported over longer periods with losses reduced to 2% per day or less. The temperature of liquid nitrogen can readily be reduced to its freezing point 63 K by placing it in a vacuum chamber pumped by a vacuum pump. Liquid nitrogens efficiency as a coolant is limited by the fact that it immediately on contact with a warmer object. This effect, known as the Leidenfrost effect, applies to any liquid in contact with an object significantly hotter than its boiling point, faster cooling may be obtained by plunging an object into a slush of liquid and solid nitrogen rather than liquid nitrogen alone. Liquid nitrogen is a compact and readily transported source of dry nitrogen gas, as it not require pressurization. g. As an energy storage medium branding cattle The culinary use of nitrogen is mentioned in an 1890 recipe book titled Fancy Ices authored by Mrs. The rapidity of chilling also leads to the formation of ice crystals. The technique is employed by chef Heston Blumenthal who has used it at his restaurant, The Fat Duck to create frozen dishes such as egg, Liquid nitrogen has also become popular in the preparation of cocktails because it can be used to quickly chill glasses or freeze ingredients. It is also added to drinks to create a smoky effect, because the liquid-to-gas expansion ratio of nitrogen is 1,694 at 20 °C, a tremendous amount of force can be generated if liquid nitrogen is rapidly vaporized in an enclosed space. In an incident on January 12,2006 at Texas A&M University, as a result of the subsequent pressure buildup, the tank failed catastrophically. Because of its low temperature, careless handling of liquid nitrogen
17.
Harold Johnson (astronomer)
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Harold Lester Johnson was an American astronomer. Johnson was awarded the Helen B, warner Prize by the American Astronomical Society in 1956. He is mostly remembered for introducing the UBV photometric system, along with William Wilson Morgan in 1953 and he died of a heart attack in Mexico City in 1980
18.
Photometer
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A photometer, generally, is an instrument that measures light intensity or the optical properties of solutions or surfaces. The relative luminous flux of a source was compared with a standard source, the photometer is placed such that the illuminance from the source being investigated is equal to the standard source, as the human eye can judge equal illuminance. The relative luminous fluxes can then be calculated as the illuminance decreases proportionally to the square of distance. A standard example of such a photometer consists of a piece of paper with an oil spot on it makes the paper slightly more transparent. When the spot is not visible from side, the illuminance from the two sides is equal. By 1861, three types were in common use and these were Rumfords photometer, Ritchies photometer, and photometers that used the extinction of shadows, which was considered to be the most precise. Most photometers detect the light with photoresistors, photodiodes or photomultipliers, some photometers measure light by counting individual photons rather than incoming flux. The operating principles are the same but the results are given in such as photons/cm2 or photons·cm−2·sr−1 rather than W/cm2 or W·cm−2·sr−1. Due to their individual photon counting nature, these instruments are limited to observations where the irradiance is low, the irradiance is limited by the time resolution of its associated detector readout electronics. With current technology this is in the megahertz range, the maximum irradiance is also limited by the throughput and gain parameters of the detector itself. The light sensing element in photon counting devices in NIR, visible, in airborne and space-based remote sensing such photon counters are used at the upper reaches of the electromagnetic spectrum such as the X-ray to far ultraviolet. Conversely, radiometers are typically used for remote sensing from the visible, photometers are used to determine the correct exposure in photography. In modern cameras, the photometer is usually built in, historically, a photometer was separate from the camera and known as an exposure meter. A reflectance photometer measures the reflectance of a surface as a function of wavelength, the surface is illuminated with white light, and the reflected light is measured after passing through a monochromator. This type of measurement has mainly practical applications, for instance in the paint industry to characterize the colour of a surface objectively and these are optical instruments for measurement of the absorption of light of a given wavelength of coloured substances in solution. From the light absorption, Beers law makes it possible to calculate the concentration of the substance in the solution. Due to its range of application and its reliability and robustness. Absorption photometers for work in aqueous solution work in the ultraviolet and visible ranges, the principle of spectrophotometers and filter photometers is that monochromatic light is allowed to pass through a container with optically flat windows containing the solution
19.
Germanium
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Germanium is a chemical element with symbol Ge and atomic number 32. It is a lustrous, hard, grayish-white metalloid in the group, chemically similar to its group neighbors tin. Pure germanium is a semiconductor with a similar to elemental silicon. Like silicon, germanium naturally reacts and forms complexes with oxygen in nature, unlike silicon, it is too reactive to be found naturally on Earth in the free state. Because it seldom appears in high concentration, germanium was discovered late in the history of chemistry. Germanium ranks near fiftieth in relative abundance of the elements in the Earths crust, in 1869, Dmitri Mendeleev predicted its existence and some of its properties from its position on his periodic table, and called the element ekasilicon. Nearly two decades later, in 1886, Clemens Winkler found the new element along with silver and sulfur, although the new element somewhat resembled arsenic and antimony in appearance, the combining ratios in compounds agreed with Mendeleevs predictions for a relative of silicon. Winkler named the element after his country, Germany, today, germanium is mined primarily from sphalerite, though germanium is also recovered commercially from silver, lead, and copper ores. Germanium metal is used as a semiconductor in transistors and various electronic devices. Historically, the first decade of semiconductor electronics was based entirely on germanium, today, the amount of germanium produced for semiconductor electronics is one fiftieth the amount of ultra-high purity silicon produced for the same. Presently, the end uses are fibre-optic systems, infrared optics, solar cell applications. Germanium compounds are used for polymerization catalysts and have most recently found use in the production of nanowires. This element forms a number of organometallic compounds, such as tetraethylgermane. Germanium is not thought to be an element for any living organism. Some complex organic compounds are being investigated as possible pharmaceuticals. Similar to silicon and aluminum, natural germanium compounds tend to be insoluble in water, however, synthetic soluble germanium salts are nephrotoxic, and synthetic chemically reactive germanium compounds with halogens and hydrogen are irritants and toxins. Because of its position in his Periodic Table, Mendeleev called it ekasilicon, in mid-1885, at a mine near Freiberg, Saxony, a new mineral was discovered and named argyrodite because of the high silver content. The chemist Clemens Winkler analyzed this new mineral, which proved to be a combination of silver, sulfur, Winkler was able to isolate the new element in 1886 and found it similar to antimony
20.
Liquid helium
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At standard pressure, the chemical element helium exists in a liquid form only at the extremely low temperature of −269 °C. Its boiling point and critical point depend on which isotope of helium is present and these are the only two stable isotopes of helium. See the table below for the values of physical quantities. The density of liquid helium-4 at its point and a pressure of one atmosphere is about 0.125 grams per cm3. Helium was first liquefied on July 10,1908, by the Dutch physicist Heike Kamerlingh Onnes at the University of Leiden in the Netherlands, at that time, helium-3 was unknown because the mass spectrometer had not yet been invented. The temperature required to produce liquid helium is low because of the weakness of the attractions between the helium atoms. These interatomic forces in helium are weak to begin with because helium is a noble gas and these are significant in helium because of its low atomic mass of about four atomic mass units. The zero point energy of helium is less if its atoms are less confined by their neighbors. Hence in liquid helium, its ground state energy can decrease by a naturally occurring increase in its average interatomic distance, however at greater distances, the effects of the interatomic forces in helium are even weaker. Because of the very weak interatomic forces in helium, this element would remain a liquid at atmospheric pressure all the way from its liquefaction point down to absolute zero, liquid helium solidifies only under very low temperatures and great pressures. At temperatures below their liquefaction points, both helium-4 and helium-3 undergo transitions to superfluids, liquid helium-4 and the rare helium-3 are not completely miscible. Below 0.9 kelvin at their saturated vapor pressure, a mixture of the two isotopes undergoes a separation into a normal fluid that floats on a denser superfluid consisting mostly of helium-4. This phase separation happens because the mass of liquid helium can reduce its thermodynamic enthalpy by separating. At extremely low temperatures, the phase, rich in helium-4. This makes possible the use of the dilution refrigerator, which is capable of reaching temperatures of a few millikelvins. Superfluid helium-4 has substantially different properties from ordinary liquid helium, general He-3 and He-4 phase diagrams, etc. Onness liquifaction of helium Kamerlingh Onness 1908 article, online and analyzed on BibNum
21.
Space telescope
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A space telescope or space observatory is an instrument located in outer space to observe distant planets, galaxies and other astronomical objects. Space telescopes avoid many of the problems of ground-based observatories, such as pollution and distortion of electromagnetic radiation. In addition, ultraviolet frequencies, X-rays and gamma rays are blocked by the Earths atmosphere, Space telescopes are distinct from other imaging satellites pointed toward Earth for purposes of espionage, weather analysis and other types of information gathering. Spitzers proposal called for a telescope that would not be hindered by Earths atmosphere. Performing astronomy from ground-based observatories on Earth is limited by the filtering, some terrestrial telescopes can reduce atmospheric effects with adaptive optics. A telescope orbiting Earth outside the atmosphere is subject neither to twinkling nor to light pollution from artificial light sources on Earth, as a result, the angular resolution of space telescopes is often much smaller than a ground-based telescope with a similar aperture. Infrared and ultraviolet are also largely blocked, however, all these advantages do come with a price. Space telescopes are much more expensive to build than ground-based telescopes, due to their location, space telescopes are also extremely difficult to maintain. The Hubble Space Telescope was serviced by the Space Shuttle while many other space telescopes cannot be serviced at all, Space observatories can generally be divided into two classes, missions which map the entire sky, and observatories which focus on selected astronomical objects or parts of the sky. Many space observatories have already completed their missions, while others continue operating, satellites have been launched and operated by NASA, ISRO, ESA, Japanese Space Agency and the Soviet space program later succeeded by Roskosmos of Russia. Many space telescopes have been launched, as of February 2017, over 20 telescopes are known to be operational
22.
Cryogenics
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In physics, cryogenics is the study of the production and behaviour of materials at very low temperatures. It is not well-defined at what point on the temperature scale refrigeration ends and cryogenics begins, but scientists assume a gas to be cryogenic if it can be liquefied at or below −150 °C. The U. S. National Institute of Standards and Technology has chosen to consider the field of cryogenics as that involving temperatures below −180 °C or −292.00 °F or 93.15 K. A person who studies elements that have been subjected to cold temperatures is called a cryogenicist. Cryogenicists use the Kelvin or Rankine temperature scales present in nature, Cryogenics The branches of physics and engineering that involve the study of very low temperatures, how to produce them, and how materials behave at those temperatures. Cryobiology The branch of biology involving the study of the effects of low temperatures on organisms, cryoconservation of animal genetic resources The conservation of genetic material with the intention of conserving a breed. Cryosurgery The branch of surgery applying very low temperatures to destroy malignant tissue, cryoelectronics The field of research regarding superconductivity at low temperatures. Cryotronics The practical application of cryoelectronics, Cryonics Cryopreserving humans and animals with the intention of future revival. Cryogenics is sometimes used to mean Cryonics in popular culture. The word cryogenics stems from Greek kρύο – cold + genic – having to do with production, Cryogenic fluids with their boiling point in kelvins Liquefied gases, such as liquid nitrogen and liquid helium, are used in many cryogenic applications. Liquid nitrogen is the most commonly used element in cryogenics and is legally purchasable around the world, Liquid helium is also commonly used and allows for the lowest attainable temperatures to be reached. These liquids may be stored in Dewar flasks, which are double-walled containers with a vacuum between the walls to reduce heat transfer into the liquid. Typical laboratory Dewar flasks are spherical, made of glass and protected in a metal outer container, Dewar flasks for extremely cold liquids such as liquid helium have another double-walled container filled with liquid nitrogen. Dewar flasks are named after their inventor, James Dewar, the man who first liquefied hydrogen, thermos bottles are smaller vacuum flasks fitted in a protective casing. Cryogenic barcode labels are used to mark dewar flasks containing these liquids, Cryogenic transfer pumps are the pumps used on LNG piers to transfer liquefied natural gas from LNG carriers to LNG storage tanks, as are cryogenic valves. The field of cryogenics advanced during World War II when scientists found that metals frozen to low temperatures showed more resistance to wear, based on this theory of cryogenic hardening, the commercial cryogenic processing industry was founded in 1966 by Ed Busch. This evolved in the late 1990s into the treatment of other parts, cryogens, such as liquid nitrogen, are further used for specialty chilling and freezing applications. Some chemical reactions, like those used to produce the active ingredients for the popular statin drugs, special cryogenic chemical reactors are used to remove reaction heat and provide a low temperature environment
23.
Water vapor
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Water vapor, water vapour or aqueous vapor, is the gaseous phase of water. It is one state of water within the hydrosphere, water vapor can be produced from the evaporation or boiling of liquid water or from the sublimation of ice. Unlike other forms of water, water vapor is invisible, under typical atmospheric conditions, water vapor is continuously generated by evaporation and removed by condensation. It is lighter than air and triggers convection currents that can lead to clouds, use of water vapor, as steam, has been important to humans for cooking and as a major component in energy production and transport systems since the industrial revolution. Likewise the detection of water vapor would indicate a similar distribution in other planetary systems. Water vapor is significant in that it can be evidence supporting the presence of extraterrestrial liquid water in the case of some planetary mass objects. Whenever a water molecule leaves a surface and diffuses into a surrounding gas, each individual water molecule which transitions between a more associated and a less associated state does so through the absorption or release of kinetic energy. The aggregate measurement of kinetic energy transfer is defined as thermal energy. Liquid water that becomes water vapor takes a parcel of heat with it, the amount of water vapor in the air determines how fast each molecule will return to the surface. When a net evaporation occurs, the body of water will undergo a net cooling directly related to the loss of water, in the US, the National Weather Service measures the actual rate of evaporation from a standardized pan open water surface outdoors, at various locations nationwide. Others do likewise around the world, the US data is collected and compiled into an annual evaporation map. The measurements range from under 30 to over 120 inches per year, formulas can be used for calculating the rate of evaporation from a water surface such as a swimming pool. In some countries, the evaporation rate far exceeds the precipitation rate, evaporative cooling is restricted by atmospheric conditions. Humidity is the amount of vapor in the air. The vapor content of air is measured with devices known as hygrometers, the measurements are usually expressed as specific humidity or percent relative humidity. This condition is referred to as complete saturation. Humidity ranges from 0 gram per cubic metre in dry air to 30 grams per cubic metre when the vapor is saturated at 30 °C, another form of evaporation is sublimation, by which water molecules become gaseous directly, leaving the surface of ice without first becoming liquid water. Sublimation accounts for the slow disappearance of ice and snow at temperatures too low to cause melting
24.
Boeing 747
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The Boeing 747 is an American wide-body commercial jet airliner and cargo aircraft, often referred to by its original nickname, Jumbo Jet. Its distinctive hump upper deck along the part of the aircraft makes it among the worlds most recognizable aircraft. First flown commercially in 1970, the 747 held the passenger capacity record for 37 years, as of January 2017, the 747 has been involved in 60 hull losses, resulting in 3722 fatalities. The four-engine 747 uses a configuration for part of its length. It is available in passenger, freighter and other versions, the 747 was expected to become obsolete after 400 were sold, but it exceeded critics expectations with production passing the 1,000 mark in 1993. By February 2017,1,528 aircraft had been built, the 747-400, the most common passenger version in service, has a high-subsonic cruise speed of Mach 0. 85–0.855 with an intercontinental range of 7,260 nautical miles. The newest version of the aircraft, the 747-8, is in production, deliveries of the 747-8F freighter version began in October 2011, deliveries of the 747-8I passenger version began in May 2012. In 1963, the United States Air Force started a series of projects on a very large strategic transport aircraft. The payload bay had to be 17 feet wide by 13.5 feet high and 100 feet long with access doors at the front. Featuring only four engines, the design required new engine designs with greatly increased power and better fuel economy. After a downselect, Boeing, Douglas, and Lockheed were given study contracts for the airframe, along with General Electric. All three of the airframe proposals shared a number of features, as the CX-HLS needed to be able to be loaded from the front, a door had to be included where the cockpit usually was. In 1965 Lockheeds aircraft design and General Electrics engine design were selected for the new C-5 Galaxy transport, the nose door and raised cockpit concepts would be carried over to the design of the 747. The 747 was conceived while air travel was increasing in the 1960s, the era of commercial jet transportation, led by the enormous popularity of the Boeing 707 and Douglas DC-8, had revolutionized long-distance travel. In 1965, Joe Sutter was transferred from Boeings 737 development team to manage the design studies for a new airliner, Sutter initiated a design study with Pan Am and other airlines, to better understand their requirements. At the time, it was thought that the 747 would eventually be superseded by supersonic transport aircraft. Boeing responded by designing the 747 so that it could be adapted easily to carry freight, in the freighter role, the clear need was to support the containerized shipping methodologies that were being widely introduced at about the same time. Standard containers are 8 ft square at the front and available in 20 and 40 ft lengths and this meant that it would be possible to support a 2-wide 2-high stack of containers two or three ranks deep with a fuselage size similar to the earlier CX-HLS project
25.
IRAS
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The Infrared Astronomical Satellite was the first-ever space telescope to perform a survey of the entire night sky at infrared wavelengths. Launched on 25 January 1983, its mission lasted ten months, the telescope was a joint project of the United States, the Netherlands, and the United Kingdom. Over 250,000 infrared sources were observed at 12,25,60, support for the processing and analysis of data from IRAS was contributed from the Infrared Processing and Analysis Center at the California Institute of Technology. Currently, the Infrared Science Archive at IPAC holds the IRAS archive, the success of early infrared space astronomy led to further missions, such as the Infrared Space Observatory and the Hubble Space Telescopes NICMOS instrument. IRAS was the first observatory to perform a survey at infrared wavelengths. It mapped 96% of the sky four times, at 12,25,60 and 100 micrometers and it discovered about 350,000 sources, many of which are still awaiting identification. About 75,000 of those are believed to be starburst galaxies, many other sources are normal stars with disks of dust around them, possibly the early stage of planetary system formation. New discoveries included a dust disk around Vega and the first images of the Milky Ways core, IRASs life, like that of most infrared satellites that followed, was limited by its cooling system. To effectively work in the domain, a telescope must be cooled to cryogenic temperatures. In IRASs case,73 kilograms of superfluid helium kept the telescope at a temperature of 2 K, the on-board supply of liquid helium was depleted after 10 months on 21 November 1983, causing the telescope temperature to rise, preventing further observations. The spacecraft continues to orbit the Earth, IRAS was designed to catalog fixed sources, so it scanned the same region of sky several times. Jack Meadows led a team at Leicester University, including John Davies and Simon Green and this led to the discovery of three asteroids, including 3200 Phaethon, six comets, and a huge dust trail associated with comet 10P/Tempel. The comets included 126P/IRAS, 161P/Hartley–IRAS, and comet IRAS–Araki–Alcock, which made an approach to the Earth in 1983. Out of the six comets IRAS found, four were long period, further analysis revealed that, of several unidentified objects, nine were distant galaxies and the tenth was intergalactic cirrus. None were found to be Solar System bodies, during its mission, IRAS detected odd infrared signatures around several stars. This led to the systems being targeted by the Hubble Space Telescopes NICMOS instrument between 1999 and 2006, but nothing was detected, in 2014, using new image processing techniques on the Hubble data, researchers discovered planetary disks around these stars. A next generation of infrared space telescopes began when NASAs Wide-field Infrared Survey Explorer launched on 14 December 2009 aboard a Delta II rocket from Vandenberg Air Force Base. A. Neugebauer, G. Habing, H. J. Clegg, P. E. Chester, Infrared Astronomical Satellite, Catalogs and Atlases
26.
Wide-field Infrared Survey Explorer
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Wide-field Infrared Survey Explorer is a NASA infrared-wavelength astronomical space telescope launched in December 2009, and placed in hibernation in February 2011 when its transmitter turned off. WISE discovered thousands of planets and numerous star clusters. Its observations also supported the discovery of the first Y Dwarf, WISE performed an all-sky astronomical survey with images in 3.4,4.6,12 and 22 μm wavelength range bands, over ten months using a 40 cm diameter infrared telescope in Earth orbit. After its hydrogen coolant depleted, a mission extension called NEOWISE was conducted to search for near-Earth objects such as comets. The All-Sky data including processed images, source catalogs and raw data, was released to the public on March 14,2012, in August 2013, NASA announced it would reactivate the WISE telescope for a new three-year mission to search for asteroids that could collide with Earth. Science operations and data processing for WISE and NEOWISE take place at the Infrared Processing, the mission was planned to create infrared images of 99 percent of the sky, with at least eight images made of each position on the sky in order to increase accuracy. The spacecraft was placed in a 525 km, circular, polar, Sun-synchronous orbit for its mission, during which it has taken 1.5 million images. Each image covers a 47-arcminute field of view, which means a 6-arcsecond resolution, each area of the sky was scanned at least 10 times at the equator, the poles were scanned at theoretically every revolution due to the overlapping of the images. The produced image library contains data on the local Solar System, the Milky Way, among the objects WISE studied are asteroids, cool, dim stars such as brown dwarfs, and the most luminous infrared galaxies. Stellar nurseries, which are covered by interstellar dust, are detectable in infrared, Infrared measurements from the WISE astronomical survey have been particularly effective at unveiling previously undiscovered star clusters. Examples of such embedded star clusters are Camargo 18, Camargo 440, Majaess 101, in addition, galaxies of the young Universe and interacting galaxies, where star formation is intensive, are bright in infrared. On this wavelength the interstellar gas clouds are also detectable, as well as proto-planetary discs, WISE satellite was expected to find at least 1,000 of those proto-planetary discs. WISE was not able to detect Kuiper belt objects, because their temperatures are too low and it was able to detect any objects warmer than 70–100 K. A Neptune-sized object would be out to 700 AU, a Jupiter-mass object out to 1 light year. A larger object of 2–3 Jupiter masses would be visible at a distance of up to 7–10 light years and that translates to about 1000 new main-belt asteroids per day, and 1–3 NEOs per day. The peak of magnitude distribution for NEOs will be about 21–22 V, WISE would detect each typical Solar System object 10–12 times over about 36 hours in intervals of 3 hours. Construction of the WISE telescope was divided between Ball Aerospace & Technologies, SSG Precision Optronics, Inc, DRS and Rockwell, Lockheed Martin, and Space Dynamics Laboratory. The program was managed through the Jet Propulsion Laboratory, the WISE instrument was built by the Space Dynamics Laboratory in Logan, Utah
27.
Infrared astronomy
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Infrared astronomy is the branch of astronomy and astrophysics that studies astronomical objects visible in infrared radiation. The wavelength of infrared light ranges from 0.75 to 300 micrometers, Infrared falls in between visible radiation, which ranges from 380 to 750 nanometers, and submillimeter waves. Infrared astronomy began in the 1830s, a few decades after the discovery of infrared light by William Herschel in 1800. Early progress was limited, and it was not until the early 20th century that conclusive detections of astronomical objects other than the Sun, both fields also use solid state detectors, though the specific type of solid state detectors used are different. Infrared light is absorbed at many wavelengths by water vapor in the Earths atmosphere, so most infrared telescopes are at elevations in dry places. There are also infrared observatories in space, including the Spitzer Space Telescope, the discovery of infrared radiation is attributed to William Herschel, who performed an experiment where he placed a thermometer in sunlight of different colors after it passed through a prism. He noticed that the temperature increase induced by sunlight was highest outside the visible spectrum and he dubbed this radiation calorific rays, and went on to show that it could be reflected, transmitted, and absorbed just like visible light. Efforts were made starting in the 1830s and continuing through the 19th century to detect infrared radiation from astronomical sources. Radiation from the Moon was first detected in 1873 by William Parsons, ernest Fox Nichols used a modified Crookes radiometer in an attempt to detect infrared radiation from Arcturus and Vega, but Nichols deemed the results inconclusive. The field was mostly neglected by traditional astronomers though until the 1960s, Infrared radiation with wavelengths just longer than visible light, known as near-infrared, behaves in a very similar way to visible light, and can be detected using similar solid state devices. For this reason, the infrared region of the spectrum is commonly incorporated as part of the optical spectrum. Many optical telescopes, such as those at Keck Observatory, operate effectively in the infrared as well as at visible wavelengths. The far-infrared extends to submillimeter wavelengths, which are observed by such as the James Clerk Maxwell Telescope at Mauna Kea Observatory. Like all other forms of radiation, infrared is utilized by astronomers to study the universe. Indeed, infrared measurements taken by the 2MASS and WISE astronomical surveys have been effective at unveiling previously undiscovered star clusters. Examples of such embedded star clusters are FSR1424, FSR1432, Camargo 394, Camargo 399, Majaess 30, and Majaess 99. Infrared telescopes, which includes most major optical telescopes as well as a few dedicated infrared telescopes, need to be chilled with liquid nitrogen, the reason for this is that objects with temperatures of a few hundred Kelvin emit most of their thermal energy at infrared wavelengths. If infrared detectors were not kept cooled, the radiation from the detector itself would contribute noise that would dwarf the radiation from any celestial source and this is particularly important in the mid-infrared and far-infrared regions of the spectrum
28.
Submillimetre astronomy
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Submillimetre astronomy or submillimeter astronomy is the branch of observational astronomy that is conducted at submillimetre wavelengths of the electromagnetic spectrum. Astronomers place the submillimetre waveband between the far-infrared and microwave wavebands, typically taken to be between a few hundred micrometres and a millimetre and it is still common in submillimetre astronomy to quote wavelengths in microns, the old name for micrometre. Using submillimetre observations, astronomers examine molecular clouds and dark cloud cores with a goal of clarifying the process of formation from earliest collapse to stellar birth. Submillimetre observations of dark clouds can be used to determine chemical abundances. In addition, submillimetre observations give information on the mechanisms for the formation and evolution of galaxies, the most significant limitation to the detection of astronomical emission at submillimetre wavelengths with ground based observatories is atmospheric emission, noise and attenuation. Like the infrared, the atmosphere is dominated by numerous water vapour absorption bands. The ideal submillimetre observing site is dry, cool, has stable weather conditions and is away from population centres. There are only a handful of sites identified, they include Mauna Kea, the Llano de Chajnantor Observatory on the Atacama Plateau, the South Pole. Comparisons show that all four sites are excellent for submillimetre astronomy, there has been some recent interest in high-altitude Arctic sites, particularly Summit Station in Greenland where the PWV measure is always better than at Mauna Kea. The Submillimeter Array is another interferometer, located at Mauna Kea, the largest existing submillimetre telescope, the James Clerk Maxwell Telescope, is also located on Mauna Kea. With high-altitude balloons and aircraft, one can get even more of the atmosphere. The BLAST experiment and SOFIA are two examples, respectively, although SOFIA can also handle near infrared observations, space-based observations at the submillimetre wavelengths remove the ground-based limitations of atmospheric absorption. The Submillimeter Wave Astronomy Satellite was launched into low Earth orbit on December 5,1998 as one of NASAs Small Explorer Program missions, the mission of the spacecraft is to make targeted observations of giant molecular clouds and dark cloud cores. The focus of SWAS is five spectral lines, water, isotopic water, isotopic carbon monoxide, molecular oxygen, the SWAS satellite was repurposed in June,2005 to provide support for the NASA Deep Impact mission. SWAS provided water production data on the comet until the end of August 2005, the European Space Agency launched a space-based mission known as the Herschel Space Observatory in 2009. Herschel deploys the largest mirror ever launched into space and studies radiation in the far infrared, rather than an Earth orbit, Herschel entered into a Lissajous orbit around L2, the second Lagrangian point of the Earth-Sun system. L2 is located approximately 1.5 million km from Earth, herschels mission focuses primarily on the origins of galaxies and galactic formation
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Infrared Space Observatory
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The Infrared Space Observatory was a space telescope for infrared light designed and operated by the European Space Agency, in cooperation with ISAS and NASA. The ISO was designed to study infrared light at wavelengths of 2.5 to 240 micrometres, the €480. 1-million satellite was launched on 17 November 1995 from the ELA-2 launch pad at the Guiana Space Centre near Kourou in French Guiana. The launch vehicle, an Ariane 44P rocket, placed ISO successfully into an elliptical geocentric orbit. The primary mirror of its Ritchey-Chrétien telescope measured 60 cm in diameter and was cooled to 1.7 Kelvin by means of superfluid helium. The ISO satellite contained four instruments that allowed for imaging and photometry from 2.5 to 240 micrometres, currently, ESA and IPAC continue efforts to improve the data pipelines and specialized software analysis tools to yield the best quality calibration and data reduction methods from the mission. IPAC supports ISO observers and data archive users through in-house visits, in 1983 the US-Dutch-British IRAS inaugurated space-based infrared astronomy by performing the first-ever all-sky survey at infrared wavelengths. The resulting map of the infrared sky pinpointed some 350,000 infrared sources waiting to be explored by IRAS successors. In 1979 IRAS was in a stage of planning and the expected results from IRAS led to the first proposal for ISO made to ESA in the same year. With the rapid improvements in infrared detector-technology, ISO was to provide detailed observations for some 30,000 infrared sources with much improved sensitivity, ISO was to perform 1000 times better in sensitivity and 100 times better in angular resolution at 12 micrometres compared to IRAS. A number of follow-up studies resulted in the selection of ISO as the installment for the ESA Scientific Programme in 1983. Next came a Call for Experiment and Mission Scientist Proposals to the scientific community, the four instruments chosen were developed by teams of researchers from France, Germany, the Netherlands and United Kingdom. Final assembly took place at the Cannes Mandelieu Space Center, the basic design of ISO was strongly influenced by that of its immediate predecessor. Like IRAS, ISO was composed of two components, Payload module, composed of a large cryostat holding the telescope and the four scientific instruments. Service module, supports the activities of the module by providing electrical power, thermal control, attitude and orbit control. The payload module also held a sun shade, to prevent stray light from reaching the telescope. The latter were part of the Attitude and Orbit Control Subsystem which provided three-axis stabilisation of ISO with an accuracy of one arc second. It consisted of Sun and Earth sensors, the star trackers. An complementary reaction control system, using hydrazine propellant, was responsible for orbital direction, the complete satellite weighed just under 2500 kg, was 5.3 m high,3.6 m wide and measured 2.3 m in depth
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Spitzer Space Telescope
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The Spitzer Space Telescope, formerly the Space Infrared Telescope Facility, is an infrared space telescope launched in 2003. It is the fourth and final of the NASA Great Observatories program, the planned mission period was to be 2.5 years with a pre-launch expectation that the mission could extend to five or slightly more years until the onboard liquid helium supply was exhausted. This occurred on 15 May 2009, without liquid helium to cool the telescope to the very low temperatures needed to operate, most of the instruments are no longer usable. All Spitzer data, from both the primary and warm phases, are archived at the Infrared Science Archive, in keeping with NASA tradition, the telescope was renamed after its successful demonstration of operation, on 18 December 2003. Unlike most telescopes that are named after famous deceased astronomers by a board of scientists, the contest led to the telescope being named in honor of astronomer Lyman Spitzer, who had promoted the concept of space telescopes in the 1940s. Spitzer wrote a 1946 report for RAND Corporation describing the advantages of an extraterrestrial observatory, the US$720 million Spitzer was launched on 25 August 2003 at 05,35,39 UTC from Cape Canaveral SLC-17B aboard a Delta II 7920H rocket. It follows a heliocentric instead of orbit, trailing and drifting away from Earths orbit at approximately 0.1 astronomical unit per year. The primary mirror is 85 centimeters in diameter, f/12, made of beryllium and was cooled to 5.5 K, by the early 1970s, astronomers began to consider the possibility of placing an infrared telescope above the obscuring effects of Earths atmosphere. Anticipating the major results from an upcoming Explorer satellite and from the Shuttle mission, long-duration spaceflights of infrared telescopes cooled to cryogenic temperatures. Earlier infrared observations had been made by both space-based and ground-based observatories, ground-based observatories have the drawback that at infrared wavelengths or frequencies, both the Earths atmosphere and the telescope itself will radiate strongly. Additionally, the atmosphere is opaque at most infrared wavelengths and this necessitates lengthy exposure times and greatly decreases the ability to detect faint objects. It could be compared to trying to observe the stars at noon, previous space observatories were launched during the 1980s and 1990s and great advances in astronomical technology have been made since then. Most of the early concepts envisioned repeated flights aboard the NASA Space Shuttle and this approach was developed in an era when the Shuttle program was expected to support weekly flights of up to 30 days duration. A May 1983 NASA proposal described SIRTF as a Shuttle-attached mission, several flights were anticipated with a probable transition into a more extended mode of operation, possibly in association with a future space platform or space station. SIRTF would be a 1-meter class, cryogenically cooled, multi-user facility consisting of a telescope, the first flight was expected to occur about 1990, with the succeeding flights anticipated beginning approximately one year later. By September 1983 NASA was considering the possibility of a long duration SIRTF mission, Spitzer is the only one of the Great Observatories not launched by the Space Shuttle, as was originally intended. However, after the 1986 Challenger disaster, the Centaur LH2–LOX upper stage, the mission underwent a series of redesigns during the 1990s, primarily due to budget considerations. This resulted in a smaller but still fully capable mission that could use the smaller Delta II expendable launch vehicle
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Akari (Astro-F)
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Akari is an infrared astronomy satellite developed by Japan Aerospace Exploration Agency, in cooperation with institutes of Europe and Korea. It was launched on 21 February 2006 at 21,28 UTC by M-V rocket into Earth sun-synchronous orbit, after its launch it was named Akari, which means light in Japanese. Earlier on, the project was known as IRIS and its primary mission was to survey the entire sky in near-, mid- and far-infrared, through its 68.5 cm aperture telescope. Its designed lifespan, of far- and mid-infrared sensors, is 550 days and its telescope mirror is made of silicon carbide to save weight. The budget for the satellite was ¥13,4 billion, by mid-August 2006, Akari finished around 50 percent of the all sky survey. By early November 2006, first all-sky survey finished, second all-sky survey started on 10 November 2006. Due to the malfunction of sun-sensor after the launch, ejection of telescope aperture lid was delayed, however, after JAXA estimated the remaining helium during early March 2007 observation time will be extended at least until 9 September. On 11 July 2007, JAXA informed that 90 percent of the sky was scanned twice, also around 3,500 selected targets have been observed so far. On 26 August 2007, liquid-Helium coolant depleted, which means the completion of far-,94 percent of the sky was scanned and more than 5,000 pointed observations were done. British and Japanese project team members were awarded a Daiwa Adrian Prize in 2004 by The Daiwa Anglo-Japanese Foundation in recognition of their collaboration, during December 2007, JAXA performed orbit correction manoeuvres to bring Akari back into its ideal orbit. This was necessary because the boiled off helium led to an increase in altitude, if this would have continued energy supply would have been cut off. In May 2011, Akari suffered an electrical failure that rendered its science instruments inoperable when the satellite is in the Earths shadow. The operation of satellite was terminated officially on 24 November 2011, star formation over three generations in the nebula IC4954/4955 in the constellation Vulpecula. Astronomy and Astrophysics, Vol.514 was an issue of Akaris result. Infrared astronomy List of space telescopes SPICA, Akaris successor space telescope JAXA/ISAS Akari mission information
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Herschel Space Observatory
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The Herschel Space Observatory was a space observatory built and operated by the European Space Agency. It was active from 2009 to 2013, and was the largest infrared telescope ever launched, carrying a single 3. 5-metre mirror and instruments sensitive to the far infrared and submillimetre wavebands. Herschel was the fourth and final mission in the Horizon 2000 programme, following SOHO/Cluster II, XMM-Newton. The observatory was carried into orbit in May 2009, reaching the second Lagrangian point of the Earth–Sun system,1,500,000 kilometres from Earth, about two months later. Herschel is named after Sir William Herschel, the discoverer of the spectrum and planet Uranus. The observatory was capable of seeing the coldest and dustiest objects in space, for example, cool cocoons where stars form, the observatory sifted through star-forming clouds—the slow cookers of star ingredients—to trace the path by which potentially life-forming molecules, such as water, form. The telescopes lifespan was governed by the amount of coolant available for its instruments, when that coolant ran out, at the time of its launch, operations were estimated to last 3.5 years. It continued to operate until 29 April 201315,20 UTC, in 1982 the Far Infrared and Sub-millimetre Telescope was proposed to ESA. The ESA long-term policy-plan Horizon 2000, produced in 1984, called for a High Throughput Heterodyne Spectroscopy mission as one of its cornerstone missions, in 1986, FIRST was adopted as this cornerstone mission. It was selected for implementation in 1993, following a study in 1992–1993. The mission concept was redesigned from Earth-orbit to the Lagrangian point L2, in 2000, FIRST was renamed Herschel. After being put out to tender in 2000, industrial activities began in 2001, as of 2010, the Herschel mission is estimated to cost 1,100 million €. This figure includes spacecraft and payload, launch and mission expenses, during the mission, Herschel made over 35,000 scientific observations and amass more than 25,000 hours worth of science data from about 600 different observing programs. The mission involved the first space observatory to cover the far infrared. At 3.5 metres wide, Herschel carried the largest optical telescope ever deployed in space and it was made not from glass but from sintered silicon carbide. The light reflected by the mirror was focused onto three instruments, whose detectors were kept at temperatures below 2 K, the instruments were cooled with over 2,300 litres of liquid helium, boiling away in a near vacuum at a temperature of approximately 1.4 K. The supply of helium on board the spacecraft was a limit to the operational lifetime of the space observatory. Herschel carried three detectors, PACS An imaging camera and low-resolution spectrometer covering wavelengths from 55 to 210 micrometres, the spectrometer had a spectral resolution between R=1000 and R=5000 and was able to detect signals as weak as −63 dB
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James Webb Space Telescope
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The James Webb Space Telescope, previously known as Next Generation Space Telescope, is a part of NASAs ongoing Flagship program. It is under construction and scheduled to launch in October 2018, the JWST will offer unprecedented resolution and sensitivity from long-wavelength visible light, through near-infrared to the mid-infrared. While the Hubble Space Telescope has a 2. 4-meter mirror, a large sunshield will keep its mirror and four science instruments below 50 K. JWSTs capabilities will enable a broad range of investigations across the fields of astronomy and cosmology. One particular goal involves observing some of the most distant events and objects in the Universe and these types of targets are beyond the reach of current ground and space-based instruments. Another goal is understanding the formation of stars and planets and this will include direct imaging of exoplanets. In gestation since 1996, the project represents a collaboration of the European Space Agency, Canadian Space Agency. It is named after James E. Webb, the administrator of NASA. NASA has described JWST as the successor of the Hubble Space Telescope. JWST has the objective to see objects, typically both older and farther away than previous instruments could assess. The result was to extend the life of Hubble until JWST as the next generation telescope could go online. This led to an altered design for JWST to obtain images deeper into the infrared than Hubble. The JWST originated in 1996 as the Next Generation Space Telescope, in 2002 it was renamed after NASAs second administrator James E. Webb, noted for playing a key role in the Apollo program and establishing scientific research as a core NASA activity. The telescope has a mass about half of Hubble Space Telescopes. The JWST is oriented toward near-infrared astronomy, but can also see orange and red light, as well as the mid-infrared region. The JWST will operate near the Earth-Sun L2 point, approximately 930,000 mi beyond the Earth, by way of comparison, Hubble orbits 340 miles above Earths surface, and the Moon is roughly 250,000 miles from Earth. This distance makes post-launch repair or upgrade of the JWST hardware virtually impossible and this will keep the temperature of the spacecraft below 50 K, necessary for infrared observations. The prime contractor is Northrop Grumman and its nominal mission time is five years, with a goal of ten years. JWST needs to use propellant to maintain its orbit around L2, which provides an upper limit to its designed lifetime
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NASA Infrared Telescope Facility
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The NASA Infrared Telescope Facility is a 3-meter telescope optimized for use in infrared astronomy and located at the Mauna Kea Observatory in Hawaii. The IRTF is operated by the University of Hawaii under an agreement with NASA. According to the IRTFs time allocation rules, at least 50% of the time is devoted to planetary science. The IRTF is a 3.0 m classical Cassegrain telescope, the Cassegrain focus f/ratio is f/38 and the primary mirror f/ratio is 2.5. Several aspects of the design of IRTF are optimized for IR observations, the secondary mirror is undersized to prevent the instrument from seeing the thermal emission from the telescope structure around the primary mirror. The primary mirror itself is 126 in diameter, but only the center 118 is used, a small mirror in the center of the secondary mirror prevents the instrument from seeing its own thermal emission. The f/ratio is long to have a secondary mirror, again to minimize the telescopes thermal emission. The mirror coatings are chosen to have minimal thermal emission, the emissivity of the telescope is usually below 4%. The secondary mirror is mounted on a mechanism to rapidly switch the pointing of the telescope from target to sky at up to 4 Hz. The IRTF is mounted on a large English yoke equatorial mount, the mount is very stiff, reducing flexure and allowing for accurate pointing of the telescope. Since the telescope is on a mount, the telescope can observe targets through the zenith without concern for field rotation. The yoke mount prevents the telescope from pointing north of +69 degrees declination, since the telescope was primarily intended for planetary science, this restriction was considered to be acceptable. Since the telescope is on a heavy mounting, it is immune from vibration or wind shake. The IRTF hosts 4 facility instruments, SpeX, NSFCam2, CSHELL, IRTF also hosts a number of visiting instruments. SpeX is a medium-resolution 0. 8-5.4 µm spectrograph built at the Institute for Astronomy, for the NASA Infrared Telescope Facility on Mauna Kea. This requirement has resulted in an instrument which provides spectral resolutions of R~1000-2000 across 0. 8-2.4 µm,2. 0-4.1 µm, single order long slit modes are also availavble. A high throughput prism mode is a provided for 0. 8-2.5 µm spectroscopy at R~100 for solid state features, a Raytheon Aladdin 3 1024x1024 InSb array is used in the spectrograph. SpeX also contains an infrared slit-viewer/guider covering a 60x60arcsec field-of-view at 0. 12arcsec/pixel, a Raytheon Aladdin 2 512x512 InSb array in the infrared slit-viewer
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Infrared Optical Telescope Array
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The Infrared Optical Telescope Array was a stellar interferometer array. On site construction went on for all 1993 and 1994, with first fringes in December 1993 and it is located at Fred Lawrence Whipple Observatory. In 2000 the third telescope came online providing closure phase observations, the array was decommissioned and disassembled in summer 2006 due to lack of funding. List of astronomical interferometers at visible and infrared wavelengths Infrared and Optical Telescope Array on the internet
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United Kingdom Infrared Telescope
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UKIRT, the United Kingdom Infra-Red Telescope, is a 3.8 metre infrared reflecting telescope, the second largest dedicated infrared telescope in the world. Until 2014 it was operated by the Joint Astronomy Centre in Hilo and located on Mauna Kea and it was owned by the United Kingdom Science and Technology Facilities Council. The telescope is set to be decommissioned in the future as part of the Mauna Kea Comprehensive Management Plan. Like related telescopes on Tenerife, it is a Cassegrain device with a primary mirror, around 2/3 thinner than in other contemporary devices. The mirror is held in a steel cell of 20 tonnes which is linked to the supports by Serrurier trusses. The instrument is held and pointed by a massive English Equatorial mounting or yoke which sits on ball-bearings on steel piers, swinging east-west and rotating around north-south. The geometry of the mount limits the access to objects between +60 and -40 degrees of declination but it is extremely sturdy and free from deformation. The telescope was built between 1975 and 1978, the systems were built by Dunford Hadfields of Sheffield and the optics by Grubb Parsons of Newcastle. Originally known as the Infrared Flux Collector it began operation in October 1979, with the delivery of the wide-field imager WFCAM in 2004, UKIRT began a revolutionary large-scale sky survey. This project takes some 80% of the telescope time in wide-field mode. Wide-field takes some 60% of the telescope, the other 40% is devoted to operations with the Cassegrain instrumentation, in December 2008 it was announced that the telescope would be moving to wide-field mode full-time. Since December 13,2010 UKIRT is operated remotely from Hilo in a minimalist operation mode, most of the time is used by the UKIRT Infrared Deep Sky Survey, but some 60+ nights per year are used by Korean institutes. A UKIRT infrared survey was used to discover a redshift distance record breaking Quasar in 2011, the Quasar could not be seen in visible light, but could in the longer wavelengths observed by UKIRT. The UKIDSS observations allowed astronomers to find the most distant quasar in 2011 and it took five years to find this item but once found, other telescopes such as the VLT further analyzed it. UKIRT was used for UKIDSS, which provided a big improvement over 2MASS, UKIRT has four Cassegrain instruments of which 3 can be on the telescope at the same time and a wide-field imager placed forward of the Cassegrain focus. CGS4 is a spectrometer with a 90-arcsecond long slit, at spectral resolutions between about 1,000 and 30,000. Michelle is a 320x240 pixel mid-infrared imager/spectrometer operating between 10 and 20 micrometres, UFTI is a 1024x1024 pixel imager operating between 0.8 and 2.5 micrometres. UIST is a 1024x1024 pixel imager/spectrometer operating between 0.8 and 5 micrometres, and offering an integral field mode 3x6 arcseconds in size
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Wide Field Infrared Survey Telescope
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On February 17,2016, WFIRST was formally designated as a mission by NASA. WFIRST is based on an existing 2. 4m wide field-of-view telescope, the Wide-Field Instrument is a 288-megapixel multi-band near-infrared camera, providing a sharpness of images comparable to that achieved by the Hubble Space Telescope over 100 times the area. The Coronagraphic Instrument is a high contrast small field of view camera and spectrometer covering visible, the design of WFIRST is based on one of the proposed designs for the Joint Dark Energy Mission between NASA and DOE. WFIRST adds some extra capabilities to the original JDEM proposal, including a search for planets using gravitational microlensing. The original design of WFIRST, studied in 2011–2012, featured a 1.3 m diameter unobstructed three-mirror anastigmat telescope and it contained a single instrument, a visible to near-infrared imager/slitless prism spectrometer. In 2012, another possibility emerged, NASA could use a second-hand National Reconnaissance Office telescope made by Harris Corporation to accomplish a mission like the one planned for WFIRST. NRO offered to donate two telescopes, the size as the Hubble Space Telescope but with a shorter focal length. This mission concept, called WFIRST-AFTA, was matured by a scientific and technical team, the WFIRST baseline design includes a coronagraph to enable the direct imaging of exoplanets. WFIRST has had a number of different implementations studied, in the most recent report, WFIRST was considered for both geosynchronous and L2 orbits. Some science cases are improved at L2, and the possibility of robotic servicing at either of the locations requires further study, the project is led by a team at NASAs Goddard Space Flight Center in Greenbelt, Maryland. If the cause is a new component, is its energy density constant in space and time. What kinds of planets exist in the cold, outer regions of planetary systems, – What determines the habitability of Earth-like worlds. Provide a coronagraph for exoplanet direct imaging that will provide the first direct images and it includes a grism for wide-field slitless spectroscopy and an integral field spectrograph for small-field spectroscopy. The second instrument is a high contrast coronagraph covering shorter wavelengths using novel starlight-suppression technology and it is intended to achieve a part-per-billion suppression of starlight to enable the detection of planets only 0.1 arcseconds away from their host stars. In fiscal year 2014, Congress provided $56 million for WFIRST, the fiscal year 2016 spending bill provided $90 million for WFIRST, far above NASAs request of $14 million, allowing the mission to enter the formulation phase in February 2016. WFIRST is on a plan for a mid-2020s launch, the total cost of WFIRST is expected at more than $2 billion, NASAs latest estimate is around $2.0 billion in 2010 dollars, which corresponds to around $2.7 billion in real year dollars. James Webb Space Telescope WFIRST page at Goddard Space Flight Center site WFIRST Science Data Center page at the Infrared Processing, $1.6 Billion Telescope Would Search Alien Planets and Probe Dark Energy — Space
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Wayback Machine
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The Internet Archive launched the Wayback Machine in October 2001. It was set up by Brewster Kahle and Bruce Gilliat, and is maintained with content from Alexa Internet, the service enables users to see archived versions of web pages across time, which the archive calls a three dimensional index. Since 1996, the Wayback Machine has been archiving cached pages of websites onto its large cluster of Linux nodes and it revisits sites every few weeks or months and archives a new version. Sites can also be captured on the fly by visitors who enter the sites URL into a search box, the intent is to capture and archive content that otherwise would be lost whenever a site is changed or closed down. The overall vision of the machines creators is to archive the entire Internet, the name Wayback Machine was chosen as a reference to the WABAC machine, a time-traveling device used by the characters Mr. Peabody and Sherman in The Rocky and Bullwinkle Show, an animated cartoon. These crawlers also respect the robots exclusion standard for websites whose owners opt for them not to appear in search results or be cached, to overcome inconsistencies in partially cached websites, Archive-It. Information had been kept on digital tape for five years, with Kahle occasionally allowing researchers, when the archive reached its fifth anniversary, it was unveiled and opened to the public in a ceremony at the University of California, Berkeley. Snapshots usually become more than six months after they are archived or, in some cases, even later. The frequency of snapshots is variable, so not all tracked website updates are recorded, Sometimes there are intervals of several weeks or years between snapshots. After August 2008 sites had to be listed on the Open Directory in order to be included. As of 2009, the Wayback Machine contained approximately three petabytes of data and was growing at a rate of 100 terabytes each month, the growth rate reported in 2003 was 12 terabytes/month, the data is stored on PetaBox rack systems manufactured by Capricorn Technologies. In 2009, the Internet Archive migrated its customized storage architecture to Sun Open Storage, in 2011 a new, improved version of the Wayback Machine, with an updated interface and fresher index of archived content, was made available for public testing. The index driving the classic Wayback Machine only has a bit of material past 2008. In January 2013, the company announced a ground-breaking milestone of 240 billion URLs, in October 2013, the company announced the Save a Page feature which allows any Internet user to archive the contents of a URL. This became a threat of abuse by the service for hosting malicious binaries, as of December 2014, the Wayback Machine contained almost nine petabytes of data and was growing at a rate of about 20 terabytes each week. Between October 2013 and March 2015 the websites global Alexa rank changed from 162 to 208, in a 2009 case, Netbula, LLC v. Chordiant Software Inc. defendant Chordiant filed a motion to compel Netbula to disable the robots. Netbula objected to the motion on the ground that defendants were asking to alter Netbulas website, in an October 2004 case, Telewizja Polska USA, Inc. v. Echostar Satellite, No.02 C3293,65 Fed. 673, a litigant attempted to use the Wayback Machine archives as a source of admissible evidence, Telewizja Polska is the provider of TVP Polonia and EchoStar operates the Dish Network
