1.
Comet
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A comet is an icy small Solar System body that, when passing close to the Sun, warms and begins to evolve gasses, a process called outgassing. This produces an atmosphere or coma, and sometimes also a tail. These phenomena are due to the effects of radiation and the solar wind acting upon the nucleus of the comet. Comet nuclei range from a few hundred metres to tens of kilometres across and are composed of collections of ice, dust. The coma may be up to 15 times the Earths diameter, if sufficiently bright, a comet may be seen from the Earth without the aid of a telescope and may subtend an arc of 30° across the sky. Comets have been observed and recorded since ancient times by many cultures, Comets usually have highly eccentric elliptical orbits, and they have a wide range of orbital periods, ranging from several years to potentially several millions of years. Short-period comets originate in the Kuiper belt or its associated scattered disc, long-period comets are thought to originate in the Oort cloud, a spherical cloud of icy bodies extending from outside the Kuiper belt to halfway to the nearest star. Long-period comets are set in motion towards the Sun from the Oort cloud by gravitational perturbations caused by passing stars, hyperbolic comets may pass once through the inner Solar System before being flung to interstellar space. The appearance of a comet is called an apparition, Comets are distinguished from asteroids by the presence of an extended, gravitationally unbound atmosphere surrounding their central nucleus. This atmosphere has parts termed the coma and the tail, however, extinct comets that have passed close to the Sun many times have lost nearly all of their volatile ices and dust and may come to resemble small asteroids. Asteroids are thought to have a different origin from comets, having formed inside the orbit of Jupiter rather than in the outer Solar System, the discovery of main-belt comets and active centaur minor planets has blurred the distinction between asteroids and comets. As of November 2014 there are 5,253 known comets, however, this represents only a tiny fraction of the total potential comet population, as the reservoir of comet-like bodies in the outer Solar System is estimated to be one trillion. Roughly one comet per year is visible to the eye, though many of those are faint. Particularly bright examples are called Great Comets, the word comet derives from the Old English cometa from the Latin comēta or comētēs. That, in turn, is a latinisation of the Greek κομήτης, Κομήτης was derived from κομᾶν, which was itself derived from κόμη and was used to mean the tail of a comet. The astronomical symbol for comets is ☄, consisting of a disc with three hairlike extensions. The solid, core structure of a comet is known as the nucleus, cometary nuclei are composed of an amalgamation of rock, dust, water ice, and frozen gases such as carbon dioxide, carbon monoxide, methane, and ammonia. As such, they are described as dirty snowballs after Fred Whipples model
2.
Apsis
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An apsis is an extreme point in an objects orbit. The word comes via Latin from Greek and is cognate with apse, for elliptic orbits about a larger body, there are two apsides, named with the prefixes peri- and ap-, or apo- added to a reference to the thing being orbited. For a body orbiting the Sun, the point of least distance is the perihelion, the terms become periastron and apastron when discussing orbits around other stars. For any satellite of Earth including the Moon the point of least distance is the perigee, for objects in Lunar orbit, the point of least distance is the pericynthion and the greatest distance the apocynthion. For any orbits around a center of mass, there are the terms pericenter and apocenter, periapsis and apoapsis are equivalent alternatives. A straight line connecting the pericenter and apocenter is the line of apsides and this is the major axis of the ellipse, its greatest diameter. For a two-body system the center of mass of the lies on this line at one of the two foci of the ellipse. When one body is larger than the other it may be taken to be at this focus. Historically, in systems, apsides were measured from the center of the Earth. In orbital mechanics, the apsis technically refers to the distance measured between the centers of mass of the central and orbiting body. However, in the case of spacecraft, the family of terms are used to refer to the orbital altitude of the spacecraft from the surface of the central body. The arithmetic mean of the two limiting distances is the length of the axis a. The geometric mean of the two distances is the length of the semi-minor axis b, the geometric mean of the two limiting speeds is −2 ε = μ a which is the speed of a body in a circular orbit whose radius is a. The words pericenter and apocenter are often seen, although periapsis/apoapsis are preferred in technical usage, various related terms are used for other celestial objects. The -gee, -helion and -astron and -galacticon forms are used in the astronomical literature when referring to the Earth, Sun, stars. The suffix -jove is occasionally used for Jupiter, while -saturnium has very rarely used in the last 50 years for Saturn. The -gee form is used as a generic closest approach to planet term instead of specifically applying to the Earth. During the Apollo program, the terms pericynthion and apocynthion were used when referring to the Moon, regarding black holes, the term peri/apomelasma was used by physicist Geoffrey A. Landis in 1998 before peri/aponigricon appeared in the scientific literature in 2002
3.
Semi-major and semi-minor axes
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In geometry, the major axis of an ellipse is its longest diameter, a line segment that runs through the center and both foci, with ends at the widest points of the perimeter. The semi-major axis is one half of the axis, and thus runs from the centre, through a focus. Essentially, it is the radius of an orbit at the two most distant points. For the special case of a circle, the axis is the radius. One can think of the axis as an ellipses long radius. The semi-major axis of a hyperbola is, depending on the convention, thus it is the distance from the center to either vertex of the hyperbola. A parabola can be obtained as the limit of a sequence of ellipses where one focus is fixed as the other is allowed to move arbitrarily far away in one direction. Thus a and b tend to infinity, a faster than b, the semi-minor axis is a line segment associated with most conic sections that is at right angles with the semi-major axis and has one end at the center of the conic section. It is one of the axes of symmetry for the curve, in an ellipse, the one, in a hyperbola. The semi-major axis is the value of the maximum and minimum distances r max and r min of the ellipse from a focus — that is. In astronomy these extreme points are called apsis, the semi-minor axis of an ellipse is the geometric mean of these distances, b = r max r min. The eccentricity of an ellipse is defined as e =1 − b 2 a 2 so r min = a, r max = a. Now consider the equation in polar coordinates, with one focus at the origin, the mean value of r = ℓ / and r = ℓ /, for θ = π and θ =0 is a = ℓ1 − e 2. In an ellipse, the axis is the geometric mean of the distance from the center to either focus. The semi-minor axis of an ellipse runs from the center of the ellipse to the edge of the ellipse, the semi-minor axis is half of the minor axis. The minor axis is the longest line segment perpendicular to the axis that connects two points on the ellipses edge. The semi-minor axis b is related to the axis a through the eccentricity e. A parabola can be obtained as the limit of a sequence of ellipses where one focus is fixed as the other is allowed to move arbitrarily far away in one direction
4.
Astronomical unit
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The astronomical unit is a unit of length, roughly the distance from Earth to the Sun. However, that varies as Earth orbits the Sun, from a maximum to a minimum. Originally conceived as the average of Earths aphelion and perihelion, it is now defined as exactly 149597870700 metres, the astronomical unit is used primarily as a convenient yardstick for measuring distances within the Solar System or around other stars. However, it is also a component in the definition of another unit of astronomical length. A variety of symbols and abbreviations have been in use for the astronomical unit. In a 1976 resolution, the International Astronomical Union used the symbol A for the astronomical unit, in 2006, the International Bureau of Weights and Measures recommended ua as the symbol for the unit. In 2012, the IAU, noting that various symbols are presently in use for the astronomical unit, in the 2014 revision of the SI Brochure, the BIPM used the unit symbol au. In ISO 80000-3, the symbol of the unit is ua. Earths orbit around the Sun is an ellipse, the semi-major axis of this ellipse is defined to be half of the straight line segment that joins the aphelion and perihelion. The centre of the sun lies on this line segment. In addition, it mapped out exactly the largest straight-line distance that Earth traverses over the course of a year, knowing Earths shift and a stars shift enabled the stars distance to be calculated. But all measurements are subject to some degree of error or uncertainty, improvements in precision have always been a key to improving astronomical understanding. Improving measurements were continually checked and cross-checked by means of our understanding of the laws of celestial mechanics, the expected positions and distances of objects at an established time are calculated from these laws, and assembled into a collection of data called an ephemeris. NASAs Jet Propulsion Laboratory provides one of several ephemeris computation services, in 1976, in order to establish a yet more precise measure for the astronomical unit, the IAU formally adopted a new definition. Equivalently, by definition, one AU is the radius of an unperturbed circular Newtonian orbit about the sun of a particle having infinitesimal mass. As with all measurements, these rely on measuring the time taken for photons to be reflected from an object. However, for precision the calculations require adjustment for such as the motions of the probe. In addition, the measurement of the time itself must be translated to a scale that accounts for relativistic time dilation
5.
Orbital eccentricity
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The orbital eccentricity of an astronomical object is a parameter that determines the amount by which its orbit around another body deviates from a perfect circle. A value of 0 is an orbit, values between 0 and 1 form an elliptical orbit,1 is a parabolic escape orbit. The term derives its name from the parameters of conic sections and it is normally used for the isolated two-body problem, but extensions exist for objects following a rosette orbit through the galaxy. In a two-body problem with inverse-square-law force, every orbit is a Kepler orbit, the eccentricity of this Kepler orbit is a non-negative number that defines its shape. The limit case between an ellipse and a hyperbola, when e equals 1, is parabola, radial trajectories are classified as elliptic, parabolic, or hyperbolic based on the energy of the orbit, not the eccentricity. Radial orbits have zero angular momentum and hence eccentricity equal to one, keeping the energy constant and reducing the angular momentum, elliptic, parabolic, and hyperbolic orbits each tend to the corresponding type of radial trajectory while e tends to 1. For a repulsive force only the trajectory, including the radial version, is applicable. For elliptical orbits, a simple proof shows that arcsin yields the projection angle of a circle to an ellipse of eccentricity e. For example, to view the eccentricity of the planet Mercury, next, tilt any circular object by that angle and the apparent ellipse projected to your eye will be of that same eccentricity. From Medieval Latin eccentricus, derived from Greek ἔκκεντρος ekkentros out of the center, from ἐκ- ek-, eccentric first appeared in English in 1551, with the definition a circle in which the earth, sun. Five years later, in 1556, a form of the word was added. The eccentricity of an orbit can be calculated from the state vectors as the magnitude of the eccentricity vector, e = | e | where. For elliptical orbits it can also be calculated from the periapsis and apoapsis since rp = a and ra = a, where a is the semimajor axis. E = r a − r p r a + r p =1 −2 r a r p +1 where, rp is the radius at periapsis. For Earths annual orbit path, ra/rp ratio = longest_radius / shortest_radius ≈1.034 relative to center point of path, the eccentricity of the Earths orbit is currently about 0.0167, the Earths orbit is nearly circular. Venus and Neptune have even lower eccentricity, over hundreds of thousands of years, the eccentricity of the Earths orbit varies from nearly 0.0034 to almost 0.058 as a result of gravitational attractions among the planets. The table lists the values for all planets and dwarf planets, Mercury has the greatest orbital eccentricity of any planet in the Solar System. Such eccentricity is sufficient for Mercury to receive twice as much solar irradiation at perihelion compared to aphelion, before its demotion from planet status in 2006, Pluto was considered to be the planet with the most eccentric orbit
6.
Orbital inclination
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Orbital inclination measures the tilt of an objects orbit around a celestial body. It is expressed as the angle between a plane and the orbital plane or axis of direction of the orbiting object. For a satellite orbiting the Earth directly above the equator, the plane of the orbit is the same as the Earths equatorial plane. The general case is that the orbit is tilted, it spends half an orbit over the northern hemisphere. If the orbit swung between 20° north latitude and 20° south latitude, then its orbital inclination would be 20°, the inclination is one of the six orbital elements describing the shape and orientation of a celestial orbit. It is the angle between the plane and the plane of reference, normally stated in degrees. For a satellite orbiting a planet, the plane of reference is usually the plane containing the planets equator, for planets in the Solar System, the plane of reference is usually the ecliptic, the plane in which the Earth orbits the Sun. This reference plane is most practical for Earth-based observers, therefore, Earths inclination is, by definition, zero. Inclination could instead be measured with respect to another plane, such as the Suns equator or the invariable plane, the inclination of orbits of natural or artificial satellites is measured relative to the equatorial plane of the body they orbit, if they orbit sufficiently closely. The equatorial plane is the perpendicular to the axis of rotation of the central body. An inclination of 30° could also be described using an angle of 150°, the convention is that the normal orbit is prograde, an orbit in the same direction as the planet rotates. Inclinations greater than 90° describe retrograde orbits, thus, An inclination of 0° means the orbiting body has a prograde orbit in the planets equatorial plane. An inclination greater than 0° and less than 90° also describe prograde orbits, an inclination of 63. 4° is often called a critical inclination, when describing artificial satellites orbiting the Earth, because they have zero apogee drift. An inclination of exactly 90° is an orbit, in which the spacecraft passes over the north and south poles of the planet. An inclination greater than 90° and less than 180° is a retrograde orbit, an inclination of exactly 180° is a retrograde equatorial orbit. For gas giants, the orbits of moons tend to be aligned with the giant planets equator, the inclination of exoplanets or members of multiple stars is the angle of the plane of the orbit relative to the plane perpendicular to the line-of-sight from Earth to the object. An inclination of 0° is an orbit, meaning the plane of its orbit is parallel to the sky. An inclination of 90° is an orbit, meaning the plane of its orbit is perpendicular to the sky
7.
Periodic comet
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Periodic comets are comets having orbital periods of less than 200 years or that have been observed during more than a single perihelion passage. Periodic comet is sometimes used to mean any comet with a periodic orbit. Periodic comets receive a permanent number prefix usually after the perihelion passage. In nearly all cases, comets are named after their discoverer, even so, quite a few comets were lost because their orbits are also affected by non-gravitational effects such as the release of gas and other material that forms the comets coma and tail. Unlike a long-period comet, the perihelion passage of a numbered periodic comet can be predicted with a high degree of accuracy. Periodic comets sometimes bear the same name repeatedly, the IAU system distinguishes between them either through the prefix or by the full designation. In the literature, a numbering system is applied to periodic comets, thus 181P and 192P are known as Comet Shoemaker–Levy 6 and Comet Shoemaker–Levy 1. Non-periodic Shoemaker–Levy comets are interleaved in this sequence, C/1991 B1 between 2 and 3, C/1991 T2 between 5 and 6, C/1993 K1 and C/1994 E2 after Shoemaker–Levy 9. In comet nomenclature, the letter before the / is either C, P, D, X, or A for an object that was identified as a comet. Some lists retain the C prefix for comets of periods larger than about 30 years until their return is confirmed
8.
Solar System
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The Solar System is the gravitationally bound system comprising the Sun and the objects that orbit it, either directly or indirectly. Of those objects that orbit the Sun directly, the largest eight are the planets, with the remainder being significantly smaller objects, such as dwarf planets, of the objects that orbit the Sun indirectly, the moons, two are larger than the smallest planet, Mercury. The Solar System formed 4.6 billion years ago from the collapse of a giant interstellar molecular cloud. The vast majority of the mass is in the Sun. The four smaller inner planets, Mercury, Venus, Earth and Mars, are terrestrial planets, being composed of rock. The four outer planets are giant planets, being more massive than the terrestrials. All planets have almost circular orbits that lie within a flat disc called the ecliptic. The Solar System also contains smaller objects, the asteroid belt, which lies between the orbits of Mars and Jupiter, mostly contains objects composed, like the terrestrial planets, of rock and metal. Beyond Neptunes orbit lie the Kuiper belt and scattered disc, which are populations of trans-Neptunian objects composed mostly of ices, within these populations are several dozen to possibly tens of thousands of objects large enough that they have been rounded by their own gravity. Such objects are categorized as dwarf planets, identified dwarf planets include the asteroid Ceres and the trans-Neptunian objects Pluto and Eris. In addition to two regions, various other small-body populations, including comets, centaurs and interplanetary dust clouds. Six of the planets, at least four of the dwarf planets, each of the outer planets is encircled by planetary rings of dust and other small objects. The solar wind, a stream of charged particles flowing outwards from the Sun, the heliopause is the point at which pressure from the solar wind is equal to the opposing pressure of the interstellar medium, it extends out to the edge of the scattered disc. The Oort cloud, which is thought to be the source for long-period comets, the Solar System is located in the Orion Arm,26,000 light-years from the center of the Milky Way. For most of history, humanity did not recognize or understand the concept of the Solar System, the invention of the telescope led to the discovery of further planets and moons. The principal component of the Solar System is the Sun, a G2 main-sequence star that contains 99. 86% of the known mass. The Suns four largest orbiting bodies, the giant planets, account for 99% of the mass, with Jupiter. The remaining objects of the Solar System together comprise less than 0. 002% of the Solar Systems total mass, most large objects in orbit around the Sun lie near the plane of Earths orbit, known as the ecliptic
9.
Edwin Holmes (astronomer)
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Edwin Alfred Holmes was an English amateur astronomer who is best remembered as the discoverer of Comet 17P/Holmes. Edwin Holmes was born in Sheffield, Yorkshire, in 1839 and he later moved to London where he worked as a seller of glass. He lived at Hornsey Rise in North London from where he observed with a 12-inch aperture reflecting telescope he had manufactured himself, Holmes was a regular contributor to the British Astronomical Association and to the magazine The English Mechanic and World of Science. He became well known for his letters to the English Mechanic, often criticising the opinions of other amateur astronomers. In particular, he argued for the use of reflecting telescopes in preference to refractors of similar cost, edwin Holmes discovered the periodic comet 17P/Holmes on 6 November 1892, and his discovery was confirmed within days at the Royal Observatory Greenwich. Holmes discovered the comet after it suddenly brightened, allowing him to notice it close in the sky to the great Andromeda Galaxy, the comet remained visible to the unaided eye for another three weeks until it faded away. 75 days later the comet once again brightened to naked-eye visibility, Holmes was later awarded the Donohoe Comet Medal of the Astronomical Society of the Pacific. He was appointed an associate of the Astronomical Society of Wales, a form of honorary membership
10.
Coma (cometary)
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The coma is the nebulous envelope around the nucleus of a comet, formed when the comet passes close to the Sun on its highly elliptical orbit, as the comet warms, parts of it sublimes. This gives a comet a fuzzy appearance when viewed in telescopes and distinguishes it from stars, the word coma comes from the Greek kome, which means hair and is the origin of the word comet itself. The coma is generally made of ice and comet dust, water dominates up to 90% of the volatiles that outflow from the nucleus when the comet is within 3-4 AU of the Sun. The parent molecule is destroyed primarily through photodissociation and to a smaller extent photoionization. The solar wind plays a role in the destruction of water compared to photochemistry. Larger dust particles are left along the orbital path while smaller particles are pushed away from the Sun into the comets tail by light pressure. Comas typically grow in size as comets approach the Sun, and they can be as large as the diameter of Jupiter, about a month after an outburst in October 2007, comet 17P/Holmes briefly had a tenuous dust atmosphere larger than the Sun. The Great Comet of 1811 also had a coma roughly the diameter of the Sun, even though the coma can become quite large, its size can actually decrease about the time it crosses the orbit of Mars around 1.5 AU from the Sun. At this distance the solar wind becomes strong enough to blow the gas and dust away from the coma, Comets were found to emit X-rays in late-March 1996. This surprised researchers, because X-ray emission is associated with very high-temperature bodies. This ripping off leads to the emission of X-rays and far ultraviolet photons, with basic Earth-surface based telescope and some technique, the size of the Coma can be calculated. Called the drift method, one locks the telescope in position and that time multiplied by the cosine of comets declination, times.25 should equal the comas diameter in arcminutes. If the distance to the comet is known, then the apparent size of the coma can be determined. In 2015, it was noted that the ALICE instrument on the ESA Rosetta spacecraft to comet 67/P, detected hydrogen, oxygen, carbon and nitrogen in the Coma, which they also called the Comets atmosphere. Alice is a spectrograph, and it found that electrons created by UV light were colliding and breaking up molecules of water. OAO-2 discovered large halos of hydrogen gas around comets, space probe Giotto detected hydrogen ions at distance of 7.8 million km away from Halley when it did close flyby of the comet in 1986. A hydrogen gas halo was detected to be 15 times the diameter of Sun and this triggered NASA to point the Pioneer Venus mission at the Comet, and it was determined that the Comet emitting 12 tons of water per second. The hydrogen gas emission has not been detected from Earths surface because those wavelengths are blocked by the atmosphere, the process by which water is broken down into hydrogen and oxygen was studied by the ALICE instrument aboard the Rosetta spacecraft
11.
Sun
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The Sun is the star at the center of the Solar System. It is a perfect sphere of hot plasma, with internal convective motion that generates a magnetic field via a dynamo process. It is by far the most important source of energy for life on Earth. Its diameter is about 109 times that of Earth, and its mass is about 330,000 times that of Earth, accounting for about 99. 86% of the total mass of the Solar System. About three quarters of the Suns mass consists of hydrogen, the rest is mostly helium, with smaller quantities of heavier elements, including oxygen, carbon, neon. The Sun is a G-type main-sequence star based on its spectral class and it formed approximately 4.6 billion years ago from the gravitational collapse of matter within a region of a large molecular cloud. Most of this matter gathered in the center, whereas the rest flattened into a disk that became the Solar System. The central mass became so hot and dense that it eventually initiated nuclear fusion in its core and it is thought that almost all stars form by this process. The Sun is roughly middle-aged, it has not changed dramatically for more than four billion years and it is calculated that the Sun will become sufficiently large enough to engulf the current orbits of Mercury, Venus, and probably Earth. The enormous effect of the Sun on Earth has been recognized since prehistoric times, the synodic rotation of Earth and its orbit around the Sun are the basis of the solar calendar, which is the predominant calendar in use today. The English proper name Sun developed from Old English sunne and may be related to south, all Germanic terms for the Sun stem from Proto-Germanic *sunnōn. The English weekday name Sunday stems from Old English and is ultimately a result of a Germanic interpretation of Latin dies solis, the Latin name for the Sun, Sol, is not common in general English language use, the adjectival form is the related word solar. The term sol is used by planetary astronomers to refer to the duration of a solar day on another planet. A mean Earth solar day is approximately 24 hours, whereas a mean Martian sol is 24 hours,39 minutes, and 35.244 seconds. From at least the 4th Dynasty of Ancient Egypt, the Sun was worshipped as the god Ra, portrayed as a falcon-headed divinity surmounted by the solar disk, and surrounded by a serpent. In the New Empire period, the Sun became identified with the dung beetle, in the form of the Sun disc Aten, the Sun had a brief resurgence during the Amarna Period when it again became the preeminent, if not only, divinity for the Pharaoh Akhenaton. The Sun is viewed as a goddess in Germanic paganism, Sól/Sunna, in ancient Roman culture, Sunday was the day of the Sun god. It was adopted as the Sabbath day by Christians who did not have a Jewish background, the symbol of light was a pagan device adopted by Christians, and perhaps the most important one that did not come from Jewish traditions
12.
Mass
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In physics, mass is a property of a physical body. It is the measure of a resistance to acceleration when a net force is applied. It also determines the strength of its gravitational attraction to other bodies. The basic SI unit of mass is the kilogram, Mass is not the same as weight, even though mass is often determined by measuring the objects weight using a spring scale, rather than comparing it directly with known masses. An object on the Moon would weigh less than it does on Earth because of the lower gravity and this is because weight is a force, while mass is the property that determines the strength of this force. In Newtonian physics, mass can be generalized as the amount of matter in an object, however, at very high speeds, special relativity postulates that energy is an additional source of mass. Thus, any body having mass has an equivalent amount of energy. In addition, matter is a defined term in science. There are several distinct phenomena which can be used to measure mass, active gravitational mass measures the gravitational force exerted by an object. Passive gravitational mass measures the force exerted on an object in a known gravitational field. The mass of an object determines its acceleration in the presence of an applied force, according to Newtons second law of motion, if a body of fixed mass m is subjected to a single force F, its acceleration a is given by F/m. A bodys mass also determines the degree to which it generates or is affected by a gravitational field and this is sometimes referred to as gravitational mass. The standard International System of Units unit of mass is the kilogram, the kilogram is 1000 grams, first defined in 1795 as one cubic decimeter of water at the melting point of ice. Then in 1889, the kilogram was redefined as the mass of the prototype kilogram. As of January 2013, there are proposals for redefining the kilogram yet again. In this context, the mass has units of eV/c2, the electronvolt and its multiples, such as the MeV, are commonly used in particle physics. The atomic mass unit is 1/12 of the mass of a carbon-12 atom, the atomic mass unit is convenient for expressing the masses of atoms and molecules. Outside the SI system, other units of mass include, the slug is an Imperial unit of mass, the pound is a unit of both mass and force, used mainly in the United States
13.
Andromeda Galaxy
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The Andromeda Galaxy, also known as Messier 31, M31, or NGC224, is a spiral galaxy approximately 780 kiloparsecs from Earth. It is the nearest major galaxy to the Milky Way and was referred to as the Great Andromeda Nebula in older texts. It received its name from the area of the sky in which it appears, the constellation of Andromeda, which was named after the mythological princess Andromeda. Andromeda is approximately 220,000 light years across, and it is the largest galaxy of the Local Group, which contains the Milky Way, the Triangulum Galaxy. The mass of the Andromeda Galaxy is estimated to be 1. 5×1012 solar masses, the Milky Way and Andromeda galaxies are expected to collide in 4.5 billion years, eventually merging to form a giant elliptical galaxy or perhaps a large disc galaxy. Around the year 964, the Persian astronomer Abd al-Rahman al-Sufi described the Andromeda Galaxy, star charts of that period labeled it as the Little Cloud. In 1612, the German astronomer Simon Marius gave a description of the Andromeda Galaxy based on telescopic observations. In 1764, Charles Messier catalogued Andromeda as object M31 and incorrectly credited Marius as the discoverer despite it being visible to the naked eye, in 1785, the astronomer William Herschel noted a faint reddish hue in the core region of Andromeda. In 1850, William Parsons, 3rd Earl of Rosse, saw, in 1864, William Huggins noted that the spectrum of Andromeda differs from a gaseous nebula. The spectra of Andromeda displays a continuum of frequencies, superimposed with dark lines that help identify the chemical composition of an object. Andromedas spectrum is similar to the spectra of individual stars. In 1885, a supernova was seen in Andromeda, the first, at the time Andromeda was considered to be a nearby object, so the cause was thought to be a much less luminous and unrelated event called a nova, and was named accordingly, Nova 1885. In 1887, Isaac Roberts took the first photographs of Andromeda, Roberts actually mistook Andromeda and similar spiral nebulae as solar systems being formed. In 1912, Vesto Slipher used spectroscopy to measure the velocity of Andromeda with respect to our solar system—the largest velocity yet measured. In 1917, Heber Curtis observed a nova within Andromeda, searching the photographic record,11 more novae were discovered. Curtis noticed that these novae were, on average,10 magnitudes fainter than those that occurred elsewhere in the sky, as a result, he was able to come up with a distance estimate of 500,000 light-years. He became a proponent of the island universes hypothesis, which held that spiral nebulae were actually independent galaxies. In 1920, the Great Debate between Harlow Shapley and Curtis took place, concerning the nature of the Milky Way, spiral nebulae, in 1922 Ernst Öpik presented a method to estimate the distance of Andromeda using the measured velocities of its stars
14.
Magnitude (astronomy)
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In astronomy, magnitude is a logarithmic measure of the brightness of an object, measured in a specific wavelength or passband, usually in the visible or near-infrared spectrum. An imprecise but systematic determination of the magnitude of objects was introduced in ancient times by Hipparchus, astronomers use two different definitions of magnitude, apparent magnitude and absolute magnitude. This distance is 10 parsecs for stars and 1 astronomical unit for planets, a minor planets size is typically estimated based on its absolute magnitude in combination with its presumed albedo. The brighter an object appears, the lower the value of its magnitude, with the brightest objects reaching negative values. The Sun has an apparent magnitude of −27, the full moon −13, the brightest planet Venus measures −5, and Sirius, an apparent magnitude can also be assigned to man-made objects in Earth orbit. The brightest satellite flares are ranked at −9, and the International Space Station, ISS, the scale is logarithmic, and defined such that each step of one magnitude changes the brightness by a factor of the fifth root of 100, or approximately 2.512. For example, a magnitude 1 star is exactly a hundred times brighter than a magnitude 6 star, the magnitude system dates back roughly 2000 years to the Greek astronomer Hipparchus who classified stars by their apparent brightness, which they saw as size. To the unaided eye, a prominent star such as Sirius or Arcturus appears larger than a less prominent star such as Mizar. For all the other Stars, which are seen by the Help of a Telescope. Note that the brighter the star, the smaller the magnitude, Bright first magnitude stars are 1st-class stars, the system was a simple delineation of stellar brightness into six distinct groups but made no allowance for the variations in brightness within a group. He concluded that first magnitude stars measured 2 arc minutes in apparent diameter, with second through sixth magnitude stars measuring 1 1⁄2′, 1 1⁄12′, 3⁄4′, 1⁄2′, the development of the telescope showed that these large sizes were illusory—stars appeared much smaller through the telescope. However, early telescopes produced a spurious disk-like image of a star that was larger for brighter stars, early photometric measurements demonstrated that first magnitude stars are about 100 times brighter than sixth magnitude stars. Thus in 1856 Norman Pogson of Oxford proposed that a scale of 5√100 ≈2.512 be adopted between magnitudes, so five magnitude steps corresponded precisely to a factor of 100 in brightness. Every interval of one magnitude equates to a variation in brightness of 5√100 or roughly 2.512 times. Consequently, a first magnitude star is about 2.5 times brighter than a second star,2.52 brighter than a third magnitude star,2.53 brighter than a fourth magnitude star. This is the modern system, which measures the brightness, not the apparent size. Using this logarithmic scale, it is possible for a star to be brighter than “first class”, so Arcturus or Vega are magnitude 0, and Sirius is magnitude −1.46. As mentioned above, the scale appears to work in reverse, the larger the negative value, the brighter
15.
Edward Walter Maunder
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Edward Walter Maunder was born in 1851, in London, the youngest child of a minister of the Wesleyan Society. He attended Kings College London but never graduated and he took a job in a London bank to finance his studies. In 1873 Maunder returned to the Royal Observatory, taking a position as a spectroscopic assistant, shortly after, in 1875, he married Edith Hannah Bustin, who gave birth to six children,3 sons,2 daughters and a son who died in infancy. She worked as a computer at the Observatory from 1890 to 1895. In 1895 Maunder and Russell married, in 1916 Annie Maunder became one of the first women accepted by the Royal Astronomical Society. After 1891, he was assisted in his work by his wife Annie Maunder, in 1904, he published their results in the form of the butterfly diagram. The period, recognised initially by Spörer, now bears the name Maunder minimum and he travelled extensively for observations going to places such as the West Indies, Lapland, India, Algiers, Mauritius. His last eclipse expedition was to Labrador for the Solar eclipse of 30 August 1905 at the invitation of the Canadian government. In 1882 Maunder observed what he called a beam, as yet unexplained. However, Maunder wrote that the phenomenon moved rapidly from horizon to horizon, further, upper tangent arc cannot occur during nighttime when the observation was made. Since he made his observation during highly intense auroral activity, he assumed it was some extraordinary auroral phenomenon and he observed Mars and was a sceptic of the notion of Martian canals. He conducted visual experiments using marked circular disks which led him to conclude, correctly, also he was convinced that there cannot be life as in our world on Mars, as there are no temperature-equating winds and too low mean temperatures. Craters on Mars and the Moon were named in his and his wife Annies honour, in 1890, Maunder was a driving force in the foundation of the British Astronomical Association. Maunder was the first editor of the Journal of the BAA and he was also director of its Mars Section 1892-1893, the Star Colour Section 1900-1901, President 1894-1896 and finally Solar Section director 1910-1925. His older brother, Thomas Frid Maunder, was a co-founder, the Indian Eclipse,1898, Report of the Expeditions Organized by the British Astronomical Association. London, Hazel, Watson, and Viney, Ld, the Royal Observatory, Greenwich—Original publication, London, The Religious Tract Society Maunder, E. Walter. Note on the Distribution of Sun-Spots in Heliographic Latitude, 1874–1902, monthly Notices of the Royal Astronomical Society. Maunder, E. Astronomy of the Bible, An Elementary Commentary on the Astronomical References in the Holy Scripture, astronomers of To-day and Their Work
16.
Royal Observatory, Greenwich
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The Royal Observatory, Greenwich is an observatory situated on a hill in Greenwich Park, overlooking the River Thames. It played a role in the history of astronomy and navigation. The observatory was commissioned in 1675 by King Charles II, with the stone being laid on 10 August. The site was chosen by Sir Christopher Wren and he appointed John Flamsteed as the first Astronomer Royal. The building was completed in the summer of 1676, the building was often called Flamsteed House, in reference to its first occupant. The scientific work of the observatory was relocated elsewhere in stages in the first half of the 20th century,1675 –22 June, Royal Observatory founded. 1675 –10 August, construction began,1714 Longitude Act established the Board of Longitude and Longitude rewards. The Astronomer Royal was, until the Board was dissolved in 1828,1767 Astronomer Royal Nevil Maskelyne began publication of the Nautical Almanac, based on observations made at the Observatory. 1833 Daily time signals began, marked by dropping a Time ball,1899 The New Physical Observatory was completed. 1924 Hourly time signals from the Royal Observatory were first broadcast on 5 February,1948 Office of the Astronomer Royal was moved to Herstmonceux. 1957 Royal Observatory completed its move to Herstmonceux, becoming the Royal Greenwich Observatory, the Greenwich site is renamed the Old Royal Observatory. Greenwich site is returned to its name, the Royal Observatory. The Ordnance Office was given responsibility for building the Observatory, with Moore providing the key instruments, Moore donated two clocks, built by Thomas Tompion, which were installed in the 20 foot high Octagon Room, the principal room of the building. They were of unusual design, each with a pendulum 13 feet in length mounted above the face, giving a period of four seconds. British astronomers have used the Royal Observatory as a basis for measurement. Four separate meridians have passed through the buildings, defined by successive instruments, subsequently, nations across the world used it as their standard for mapping and timekeeping. When the Airy circle became the reference for the meridian, the difference resulting from the change was considered enough to be neglected. When a new triangulation was done between 1936 and 1962, scientists determined that in the Ordnance Survey system the longitude of the international Greenwich meridian was not 0° and this old astronomical prime meridian has been replaced by a more precise prime meridian
17.
Greenwich
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Greenwich is an early-established district of todays London, England, centred 5.5 miles east south-east of Charing Cross. The town lends its name to the Royal Borough of Greenwich, Greenwich is generally described as being part of South-east London and sometimes as being part of East London. Greenwich is notable for its history and for giving its name to the Greenwich Meridian. The town became the site of a palace, the Palace of Placentia from the 15th century. The palace fell into disrepair during the English Civil War and was rebuilt as the Royal Naval Hospital for Sailors by Sir Christopher Wren and his assistant Nicholas Hawksmoor. These buildings became the Royal Naval College in 1873, and they remained an establishment for military education until 1998 when they passed into the hands of the Greenwich Foundation. The historic rooms within these buildings remain open to the public, other buildings are used by University of Greenwich and Trinity Laban Conservatoire of Music and Dance. The town became a resort in the 18th century and many grand houses were built there, such as Vanbrugh Castle established on Maze Hill. From the Georgian period estates of houses were constructed above the town centre, Greenwich formed part of Kent until 1889 when the County of London was created. The place-name Greenwich is first attested in a Saxon charter of 918 and it is recorded as Grenewic in 964, and as Grenawic in the Anglo-Saxon Chronicle for 1013. It is Grenviz in the Domesday Book of 1086, and Grenewych in the Taxatio Ecclesiastica of 1291, the name means green wic or settlement. An article in The Times of 13 October 1967 stated, East Greenwich, gateway to the Blackwall Tunnel, remains solidly working class, the manpower for one eighth of Londons heavy industry. West Greenwich is a hybrid, the spirit of Nelson, the Cutty Sark, the Maritime Museum, an industrial waterfront and a number of elegant houses, ripe for development. Royal charters granted to English colonists in North America, often used the name of the manor of East Greenwich for describing the tenure as that of free socage, New England charters provided that the grantees should hold their lands as of his Majesty’s manor of East Greenwich. Grants named the castle of Windsor, places in North America that have taken the name East Greenwich include a township in Gloucester County, New Jersey, a hamlet in Washington County, New York, and a town in Kent County, Rhode Island. Tumuli to the south-west of Flamsteed House, in Greenwich Park, are thought to be early Bronze Age barrows re-used by the Saxons in the 6th century as burial grounds, to the east between the Vanbrugh and Maze Hill Gates is the site of a Roman villa or temple. A small area of red paving tesserae protected by railings marks the spot and it was excavated in 1902 and 300 coins were found dating from the emperors Claudius and Honorius to the 5th century. This was excavated by the Channel 4 television programme Time Team in 1999, broadcast in 2000, the Roman road from London to Dover, Watling Street crossed the high ground to the south of Greenwich, through Blackheath
18.
England
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England is a country that is part of the United Kingdom. It shares land borders with Scotland to the north and Wales to the west, the Irish Sea lies northwest of England and the Celtic Sea lies to the southwest. England is separated from continental Europe by the North Sea to the east, the country covers five-eighths of the island of Great Britain in its centre and south, and includes over 100 smaller islands such as the Isles of Scilly, and the Isle of Wight. England became a state in the 10th century, and since the Age of Discovery. The Industrial Revolution began in 18th-century England, transforming its society into the worlds first industrialised nation, Englands terrain mostly comprises low hills and plains, especially in central and southern England. However, there are uplands in the north and in the southwest, the capital is London, which is the largest metropolitan area in both the United Kingdom and the European Union. In 1801, Great Britain was united with the Kingdom of Ireland through another Act of Union to become the United Kingdom of Great Britain and Ireland. In 1922 the Irish Free State seceded from the United Kingdom, leading to the latter being renamed the United Kingdom of Great Britain, the name England is derived from the Old English name Englaland, which means land of the Angles. The Angles were one of the Germanic tribes that settled in Great Britain during the Early Middle Ages, the Angles came from the Angeln peninsula in the Bay of Kiel area of the Baltic Sea. The earliest recorded use of the term, as Engla londe, is in the ninth century translation into Old English of Bedes Ecclesiastical History of the English People. According to the Oxford English Dictionary, its spelling was first used in 1538. The earliest attested reference to the Angles occurs in the 1st-century work by Tacitus, Germania, the etymology of the tribal name itself is disputed by scholars, it has been suggested that it derives from the shape of the Angeln peninsula, an angular shape. An alternative name for England is Albion, the name Albion originally referred to the entire island of Great Britain. The nominally earliest record of the name appears in the Aristotelian Corpus, specifically the 4th century BC De Mundo, in it are two very large islands called Britannia, these are Albion and Ierne. But modern scholarly consensus ascribes De Mundo not to Aristotle but to Pseudo-Aristotle, the word Albion or insula Albionum has two possible origins. Albion is now applied to England in a poetic capacity. Another romantic name for England is Loegria, related to the Welsh word for England, Lloegr, the earliest known evidence of human presence in the area now known as England was that of Homo antecessor, dating to approximately 780,000 years ago. The oldest proto-human bones discovered in England date from 500,000 years ago, Modern humans are known to have inhabited the area during the Upper Paleolithic period, though permanent settlements were only established within the last 6,000 years
19.
William Maw
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William Henry Maw was a British civil engineer and astronomer. Born into a family and orphaned at age 16, Maw was taken into the workshops of the Eastern Counties Railway as an assistant before progressing to the design office as a draughtsman. He was made the head of the office and designed the first outside cylinder locomotive for use in India, in 1865 he founded the journal Engineering and remained an editor for the rest of his life. He left the railway and became a consulting engineer his many works including printing presses for several newspapers and he was president of the Civil and Mechanical Engineers Society, the Institution of Mechanical Engineers and the Institution of Civil Engineers. Maw was also an astronomer and was a Fellow of the Royal Astronomical Society with a particular interest in double stars. He co-founded the British Astronomical Association for amateur astronomers and served as its treasurer and he later became a council member, treasurer and president of the RAS. During the First World War he served his country as a member for the Ministry of Munitions. Maw was born in Scarborough on 6 December 1838 into a family, his father was a captain of the Merchant Navy. He was privately educated at Sykes School in his hometown and it was there that he befriended Edward Harland who would later co-found the Harland and Wolff shipbuilding company. In 1853 his father was lost at sea, leaving the family without an income, his mother died shortly afterwards, in March 1855 he was taken on as an assistant first in the carriage and then the locomotive workshops of the Eastern Counties Railway at Stratford Works. During this period he studied drawing at the Mechanics Institute, later to become Birkbeck College and he was so talented at drawing that in 1859, at the age of 21, he was made head of the office. In 1865 he left Eastern Counties and, with Zerah Colburn and he would remain an editor of the journal for the rest of his life. He was made a fellow of the RAS on 14 December 1888 and he co-founded the British Astronomical Association, an amateur astronomy association, and served as its treasurer from 1890 to 1913 and its president from 1898 to 1900. In 1892 he was elected as a member of the council of the RAS, serving as treasurer from 1900 to 1905, Maw was created an honorary Doctor of Laws by the University of Glasgow in 1909 for his contributions to mechanical engineering. He served upon the board of the National Physical Laboratory and on committees for the Ministry of Munitions during the First World War. He died at home on 19 March 1924 and was survived by his wife, Maw from the Lick Observatory Records Digital Archive, UC Santa Cruz Librarys Digital Collections
20.
Kensington
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Kensington is an affluent district within the Royal Borough of Kensington and Chelsea in West London. Its commercial heart is Kensington High Street, the affluent and densely populated area contains the major museum district of South Kensington, which has the Royal Albert Hall for music and nearby Royal College of Music. The area is home to many of Londons European embassies, the first mention of the area is in the Domesday Book of 1086, where it was written in Latin as Chenesitone, which has been interpreted to have originally been Kenesignetun in Anglo-Saxon. A variation may be Kesyngton, in 1396 and he in turn granted the tenancy of Kensington to his vassal Aubrey de Vere I, who was holding the manor in 1086, according to Domesday Book. The bishops heir, Robert de Mowbray, rebelled against William Rufus, Aubrey de Vere I had his tenure converted to a tenancy in-chief, holding Kensington after 1095 directly of the crown. He granted land and church there to Abingdon Abbey at the deathbed request of his young eldest son, Geoffrey. As the Veres became the earls of Oxford, their estate at Kensington came to be known as Earls Court, while the Abingdon lands were called Abbots Kensington and the church St Mary Abbots. The original Kensington Barracks, built at Kensington Gate in the late 18th century, were demolished in 1858, the focus of the area is Kensington High Street, a busy commercial centre with many shops, typically upmarket. The street was declared Londons second best shopping street in February 2005 thanks to its range, however, since October 2008 the street has faced competition from the Westfield shopping centre in nearby White City. Kensingtons second group of buildings is at South Kensington, where several streets of small to medium-sized shops. This is also the end of Exhibition Road, the thoroughfare that serves the areas museums. To the west, a border is kept along the line of the Counter Creek marked by the West London railway line, in the north east, the large Royal Park of Kensington Gardens is a green buffer. The other main area in Kensington is Holland Park, just north of Kensington High Street. Kensington is, in general, an affluent area, a trait that it now shares with its neighbour to the south. In early 2007, houses sold in Upper Phillimore Gardens for in excess of £20 million, Kensington is also very densely populated, it forms part of the most densely populated local government district in the United Kingdom. This high density is not formed from high-rise buildings, instead, unlike northern extremities of the Borough, Kensington lacks high-rise buildings except for the Holiday Inns London Kensington Forum Hotel in Cromwell Road, which is a 27-storey building. The Olympia exhibition hall is just over the border in West Kensington. Kensington is part of the Royal Borough of Kensington and Chelsea, the head office of newspaper group DMGT is located in Northcliffe House in Kensington, which is the office part of the large Barkers building
21.
London
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London /ˈlʌndən/ is the capital and most populous city of England and the United Kingdom. Standing on the River Thames in the south east of the island of Great Britain and it was founded by the Romans, who named it Londinium. Londons ancient core, the City of London, largely retains its 1. 12-square-mile medieval boundaries. London is a global city in the arts, commerce, education, entertainment, fashion, finance, healthcare, media, professional services, research and development, tourism. It is crowned as the worlds largest financial centre and has the fifth- or sixth-largest metropolitan area GDP in the world, London is a world cultural capital. It is the worlds most-visited city as measured by international arrivals and has the worlds largest city airport system measured by passenger traffic, London is the worlds leading investment destination, hosting more international retailers and ultra high-net-worth individuals than any other city. Londons universities form the largest concentration of education institutes in Europe. In 2012, London became the first city to have hosted the modern Summer Olympic Games three times, London has a diverse range of people and cultures, and more than 300 languages are spoken in the region. Its estimated mid-2015 municipal population was 8,673,713, the largest of any city in the European Union, Londons urban area is the second most populous in the EU, after Paris, with 9,787,426 inhabitants at the 2011 census. The citys metropolitan area is the most populous in the EU with 13,879,757 inhabitants, the city-region therefore has a similar land area and population to that of the New York metropolitan area. London was the worlds most populous city from around 1831 to 1925, Other famous landmarks include Buckingham Palace, the London Eye, Piccadilly Circus, St Pauls Cathedral, Tower Bridge, Trafalgar Square, and The Shard. The London Underground is the oldest underground railway network in the world, the etymology of London is uncertain. It is an ancient name, found in sources from the 2nd century and it is recorded c.121 as Londinium, which points to Romano-British origin, and hand-written Roman tablets recovered in the city originating from AD 65/70-80 include the word Londinio. The earliest attempted explanation, now disregarded, is attributed to Geoffrey of Monmouth in Historia Regum Britanniae and this had it that the name originated from a supposed King Lud, who had allegedly taken over the city and named it Kaerlud. From 1898, it was accepted that the name was of Celtic origin and meant place belonging to a man called *Londinos. The ultimate difficulty lies in reconciling the Latin form Londinium with the modern Welsh Llundain, which should demand a form *lōndinion, from earlier *loundiniom. The possibility cannot be ruled out that the Welsh name was borrowed back in from English at a later date, and thus cannot be used as a basis from which to reconstruct the original name. Until 1889, the name London officially applied only to the City of London, two recent discoveries indicate probable very early settlements near the Thames in the London area
22.
Bramley, Surrey
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Bramley is a village and civil parish about three miles south of Guildford in the Borough of Waverley in Surrey, south east England. Most of the lies in the Surrey Hills Area of Outstanding Natural Beauty. In its bounds is evidence of the age but documents record a village at the end of Anglo Saxon era of the Kingdom of England. Much of the housing was linear along the Horsham road, many buildings have survived. Bramley is like most villages Old English, Birtley within the parish in the south and means a clearing in the birch. Before the Saxons arrived the area was lightly settled. The settlement appears in six large parcels in the Domesday Book as Brolege and these were held by the Bishop of Bayeux. Its Domesday Assets were, 39½ hides,3 churches,5 mills worth £1 6s 0d,39 ploughs,20 acres of meadow, woodland worth 100 hogs. In 1086 its wide definition and well-cultivated, fertile area with valuable mills made Bramley by yearly income the largest and most valuable manor in Surrey and it rendered, £83 14s 8d to its feudal overlords. The area comprised most of the half of the Hundred of Blackheath, extending to the Sussex border and including Shalford, Wonersh, Hascombe. The Anglo-Saxon settlers of neighbouring Wonersh – the name means a crooked field – and any Celts not displaced by them may have been the people who developed the Linish, Bramley. This name means a field and in 1843, when the Tithe Assessment map was drawn, it covered the area now occupied by the Library, Blunden Court. Flax was used to make linen but before spinning and weaving the stems were retted, soaking in running water, Cranleigh Waters flows through and drains the village. There were two mills – probably both here at the time of the Domesday survey, Bramley Mill and Snowdenham Mill, to the latter of which Emply Lane led from the land around Wintershall. Coronation Oak green today is all that remains of the village green at the centre of the village. There is a reference to a manor house near the village green. Wonersh is only 0.5 miles away from Station Road, by the mid 16th century there were 63 houses in what was called Bramley township,22 of them within half a mile of the church. Bramley Church, dedicated to the Holy Trinity, dates from the 12th century with additions in the 13th century
23.
Edinburgh
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Edinburgh is the capital city of Scotland and one of its 32 local government council areas. Located in Lothian on the Firth of Forths southern shore, it is Scotlands second most populous city and the seventh most populous in the United Kingdom. The 2014 official population estimates are 464,990 for the city of Edinburgh,492,680 for the authority area. Recognised as the capital of Scotland since at least the 15th century, Edinburgh is home to the Scottish Parliament and it is the largest financial centre in the UK after London. Historically part of Midlothian, the city has long been a centre of education, particularly in the fields of medicine, Scots law, literature, the sciences and engineering. The University of Edinburgh, founded in 1582 and now one of four in the city, was placed 17th in the QS World University Rankings in 2013 and 2014. The city is famous for the Edinburgh International Festival and the Fringe. The citys historical and cultural attractions have made it the United Kingdoms second most popular tourist destination after London, attracting over one million overseas visitors each year. Historic sites in Edinburgh include Edinburgh Castle, Holyrood Palace, the churches of St. Giles, Greyfriars and the Canongate, Edinburghs Old Town and New Town together are listed as a UNESCO World Heritage Site, which has been managed by Edinburgh World Heritage since 1999. It appears to derive from the place name Eidyn mentioned in the Old Welsh epic poem Y Gododdin, the poem names Din Eidyn as a hill fort in the territory of the Gododdin. The Celtic element din was dropped and replaced by the Old English burh, the first documentary evidence of the medieval burgh is a royal charter, c. 1124–1127, by King David I granting a toft in burgo meo de Edenesburg to the Priory of Dunfermline. In modern Gaelic, the city is called Dùn Èideann, the earliest known human habitation in the Edinburgh area was at Cramond, where evidence was found of a Mesolithic camp site dated to c.8500 BC. Traces of later Bronze Age and Iron Age settlements have found on Castle Rock, Arthurs Seat, Craiglockhart Hill. When the Romans arrived in Lothian at the end of the 1st century AD, at some point before the 7th century AD, the Gododdin, who were presumably descendants of the Votadini, built the hill fort of Din Eidyn or Etin. Although its location has not been identified, it likely they would have chosen a commanding position like the Castle Rock, Arthurs Seat. In 638, the Gododdin stronghold was besieged by forces loyal to King Oswald of Northumbria and it thenceforth remained under their jurisdiction. The royal burgh was founded by King David I in the early 12th century on land belonging to the Crown, in 1638, King Charles Is attempt to introduce Anglican church forms in Scotland encountered stiff Presbyterian opposition culminating in the conflicts of the Wars of the Three Kingdoms. In the 17th century, Edinburghs boundaries were defined by the citys defensive town walls
24.
Mackay, Queensland
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Mackay /məˈkaɪ/ is a city and its centre suburb in the Mackay Region on the eastern coast of Queensland, Australia. It is located about 970 kilometres north of Brisbane, on the Pioneer River, Mackay is nicknamed the sugar capital of Australia because its region produces more than a third of Australias cane sugar. There is controversy about the location of the region for administrative purposes, indeed, much confusion lies within the Queensland Government, with government services being provided through both Townsville and Rockhampton. Generally, the area is known as the Mackay–Whitsunday Region, the city was named after John Mackay. In 1860, he was the leader of an expedition into the Pioneer Valley, initially Mackay proposed to name the river Mackay River after his father George Mackay. Thomas Henry Fitzgerald surveyed the township and proposed it was called Alexandra after Princess Alexandra of Denmark, Fitzgerald then decided to use the name Alexandra for his sugar cane plantation and sugar mill, which eventually provided the name to the Mackay suburb of Alexandra today. There has always been much contention over the pronunciation of the name Mackay, the area which is now Mackay City was originally inhabited by the local Yuibera people. It was during this trip that the Endeavours botanist, Sir Joseph Banks, in 1860, John Mackay led an expedition to the Pioneer Valley and was the first European to visit the area now named after him. In 1918, Mackay was hit by a tropical cyclone causing severe damage and loss of life with hurricane-force winds. The resulting death toll was increased by an outbreak of bubonic plague. The foundation stone of the Mackay War Memorial was laid on the bank on 18 November 1928 by the mayor George Albert Milton. It was unveiled on 1 May 1929 by the mayor, due to flooding, the memorial was relocated to Jubilee Park in 1945. Due to the construction of the Civic Centre, it was relocated to part of the park in March 1973. On 18 February 1958, Mackay was hit with massive flooding caused by heavy rainfall upstream with 878 mm of rain falling at Finch Hatton in 24 hours, the flood peaked at 9.14 metres. The water flowed down the valley and flooded Mackay within hours, residents were rescued off rooftops by boats and taken to emergency accommodation. On 15 February 2008, almost exactly 50 years from the last major flood, the Rats of Tobruk Memorial commemorates those who died at and since the Battle of Tobruk. The memorial was dedicated on 4 March 2001, Mackay was battered by Tropical Cyclone Ului, a category three cyclone which crossed the coast at nearby Airlie Beach, around 1,30 am on Sunday 21 March 2010. Over 60,000 homes lost power and some services also failed during the storm
25.
Queensland
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Queensland is the second-largest and third-most-populous state in the Commonwealth of Australia. Situated in the north-east of the country, it is bordered by the Northern Territory, South Australia and New South Wales to the west, south-west, to the east, Queensland is bordered by the Coral Sea and Pacific Ocean. Queensland has a population of 4,750,500, concentrated along the coast, the state is the worlds sixth largest sub-national entity, with an area of 1,852,642 km2. The capital and largest city in the state is Brisbane, Australias third largest city, often referred to as the Sunshine State, Queensland is home to 10 of Australias 30 largest cities and is the nations third largest economy. Tourism in the state, fuelled largely by its tropical climate, is a major industry. Queensland was first inhabited by Aboriginal Australians and Torres Strait Islanders, the first European to land in Queensland was Dutch navigator Willem Janszoon in 1606, who explored the west coast of the Cape York Peninsula near present-day Weipa. In 1770, Lieutenant James Cook claimed the east coast of Australia for the Kingdom of Great Britain. The colony of New South Wales was founded in 1788 by Governor Arthur Phillip at Sydney, New South Wales at that time included all of what is now Queensland, Queensland was explored in subsequent decades until the establishment of a penal colony at Brisbane in 1824 by John Oxley. Penal transportation ceased in 1839 and free settlement was allowed from 1842, the state was named in honour of Queen Victoria, who on 6 June 1859 signed Letters Patent separating the colony from New South Wales. The 6th of June is now celebrated statewide as Queensland Day. Queensland achieved statehood with the Federation of Australia on 1 January 1901, the history of Queensland spans thousands of years, encompassing both a lengthy indigenous presence, as well as the eventful times of post-European settlement. The north-eastern Australian region was explored by Dutch, Spanish and French navigators before being encountered by Lieutenant James Cook in 1770, the Australian Labor Party has its origin as a formal organisation in Queensland and the town of Barcaldine is the symbolic birthplace of the party. June 2009 marked the 150th anniversary of its creation as a colony from New South Wales. The Aboriginal occupation of Queensland is thought to predate 50,000 BC, likely via boat or land bridge across Torres Strait, during the last ice age Queenslands landscape became more arid and largely desolate, making food and other supplies scarce. This led to the worlds first seed-grinding technology, warming again made the land hospitable, which brought high rainfall along the eastern coast, stimulating the growth of the states tropical rainforests. In February 1606, Dutch navigator Willem Janszoon landed near the site of what is now Weipa and this was the first recorded landing of a European in Australia, and it also marked the first reported contact between European and Aboriginal Australian people. The region was explored by French and Spanish explorers prior to the arrival of Lieutenant James Cook in 1770. Cook claimed the east coast under instruction from King George III of the United Kingdom on 22 August 1770 at Possession Island, naming Eastern Australia, including Queensland, the Aboriginal population declined significantly after a smallpox epidemic during the late 18th century
26.
Heinrich Kreutz
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The group is now known as the Kreutz Sungrazers, and has produced some of the brightest comets ever seen. Kreutz was born in Siegen in 1854, and obtained his PhD at the University of Bonn in 1880 on the orbit of comet C/1861 J1, in 1882 he moved to Kiel, working at the observatory and university there. In 1896 he became the editor of the Astronomische Nachrichten, the leading journal of the time. Obituary -1907, Publications of the Astronomical Society of the Pacific, v.19, p.248 Biography from SEDS
27.
George Mary Searle
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George Mary Searle was an American astronomer and Catholic priest. He discovered the asteroid 55 Pandora in 1858, in later life he became a member of the Paulist order and taught at The Catholic University of America. In 1905 Searle published his idea for a reform of the Gregorian Calendar. The plan was to have every new year beginning on Sunday, in common years the new calendar would have 52 weeks exactly, or 364 days, with February shortened to 27 days. In leap years, there would be 53 weeks, or 371 days, the extra week would be added as a holiday week, between April and May. Leap years would occur every year, except for years divisible by 50. The result would be a calendar with 20,871 weeks in 400 years, list of Roman Catholic scientist-clerics Leap week calendar The Catholic Encyclopedia and Its Makers, p.157, archive. org. A Possible Calendar, The Catholic World, A Monthly Magazine of General Literature and Science, a Possible Calendar George Mary Searle on Findagrave. com
28.
Perihelion and aphelion
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The perihelion is the point in the orbit of a celestial body where it is nearest to its orbital focus, generally a star. It is the opposite of aphelion, which is the point in the orbit where the body is farthest from its focus. The word perihelion stems from the Ancient Greek words peri, meaning around or surrounding, aphelion derives from the preposition apo, meaning away, off, apart. According to Keplers first law of motion, all planets, comets. Hence, a body has a closest and a farthest point from its parent object, that is, a perihelion. Each extreme is known as an apsis, orbital eccentricity measures the flatness of the orbit. Because of the distance at aphelion, only 93. 55% of the solar radiation from the Sun falls on a given area of land as does at perihelion. However, this fluctuation does not account for the seasons, as it is summer in the northern hemisphere when it is winter in the southern hemisphere and vice versa. Instead, seasons result from the tilt of Earths axis, which is 23.4 degrees away from perpendicular to the plane of Earths orbit around the sun. Winter falls on the hemisphere where sunlight strikes least directly, and summer falls where sunlight strikes most directly, in the northern hemisphere, summer occurs at the same time as aphelion. Despite this, there are larger land masses in the northern hemisphere, consequently, summers are 2.3 °C warmer in the northern hemisphere than in the southern hemisphere under similar conditions. Apsis Ellipse Solstice Dates and times of Earths perihelion and aphelion, 2000–2025 from the United States Naval Observatory
29.
Biela's Comet
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Bielas Comet or Comet Biela was a periodic Jupiter-family comet first recorded in 1772 by Montaigne and Messier and finally identified as periodic in 1826 by Wilhelm von Biela. It was subsequently observed to split in two and has not been seen since 1852, as a result it is currently considered to have been destroyed, although remnants appeared to have survived for some time as a meteor shower, the Andromedids. The comet was first recorded on 8 March 1772 by Jacques Leibax Montaigne and it was also recorded in 1805 by Jean-Louis Pons, but was not recognized as the same object.6 years. At the time it was only the third comet known to be periodic, after comets Halley, a third claim was made by Thomas Clausen, who had independently linked the comets. The comet appeared as predicted during its 1832 apparition, when it was first recovered by John Herschel on 24 September. Despite this, the fact that Bielas Comet was the comet known to intersect the Earths orbit was to make it of particular interest. The 1839 apparition was extremely unfavourable and no observations were made, the comet was recovered on November 26,1845, by Francesco de Vico. Initially a small, faint nebulosity, subsequent observations showed that something remarkable had happened to it, matthew Fontaine Maury, observing on 14 January 1846, noted that an apparent companion was located 1 arc minute north of the comet. After this announcement many astronomers began observing the comet, and noted that the two alternated in brightness, developing parallel tails as they approached perihelion. In 1852 the comet was recovered more or less as predicted, with Comet A being recovered first. Comet B was finally relocated on September 16, and once again both nuclei alternated in brightness during the period of observation, a was last detected on this apparition on September 26 and B on September 29, in both cases by Otto Wilhelm Struve. Neither part could be found on their periodic returns in 1859,1865. However, on November 27,1872, a brilliant meteor shower was observed radiating from the part of the sky where the comet had been predicted to cross in September 1872 and this was the date when Earth intersected the comets trajectory. These meteors became known as the Andromedids or Bielids and it seems apparent that they were produced by the breakup of the comet. The meteors were seen again on subsequent occasions for the rest of the 19th century, there were, however, inconclusive observations during the 1865 and 1872 returns. Charles Talmage, using ephemerides provided by John Russell Hind, claimed to have observed a nebulous object in approximately the right position in November 1865. Despite the apparent destruction of the comet, there were a number of searches for it during the later 20th century and it has been calculated that the mass of the debris left in the Andromedid meteor stream is still much less than the total mass of the comet. Given that it is likely that the main mass loss occurred near aphelion before the 1845 apparition
30.
Lost comet
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The D/ designation is for a periodic comet that no longer exists or is deemed to have disappeared. Some astronomers have specialized in this area, such as Brian G. Marsden, there are a number of reasons why a comet might be missed by astronomers during subsequent apparitions. Firstly, cometary orbits may be perturbed by interaction with the giant planets and this, along with nongravitational forces, can result in changes to the date of perihelion. As some comets periodically undergo outbursts or flares in brightness, it may be possible for a faint comet to be discovered during an outburst. Comets can also run out of volatiles and this may have occurred in the case of 5D/Brorsen, which was considered by Marsden to have probably faded out of existence in the late 19th century. Comets are in some known to have disintegrated during their perihelion passage. The best-known example is Bielas Comet, which was observed to split into two components before disappearing after its 1852 apparition, in modern times 73P/Schwassmann–Wachmann has been observed in the process of breaking up. In the case of lost comets this is especially tricky, for example, the comet 177P/Barnard, discovered by Edward Emerson Barnard on June 24,1889, was rediscovered after 116 years in 2006. On July 19,2006, 177P came within 0.36 AU of the Earth, comets can be gone but not considered lost, even though they may not be expected back for hundreds or even thousands of years. With more powerful telescopes it has become possible to observe comets for longer periods of time after perihelion, for example, Comet Hale–Bopp was observable with the naked eye about 18 months after its approach in 1997. It is expected to remain observable with large telescopes until perhaps 2020, comets that have been lost or which have disappeared have names beginning with a D according to current IAU conventions. Comets are typically observed on a periodic return, when they do not they are sometimes found again, while other times they may break up into fragments. These fragments can sometimes be observed, but the comet is no longer expected to return. Other times a comet will not be considered lost until it does not appear at a predicted time, comets may also collide with another object, such as Comet Shoemaker–Levy 9, which collided with Jupiter in 1994
31.
Elizabeth Roemer
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Elizabeth Roemer was an American astronomer whose research interests centered on comets and asteroids. Roemer was a professor at the University of Arizona and she discovered the two main-belt asteroids 1930 Lucifer and 1983 Bok. In addition, she took a set of photographic plates of comets over 25 years. She recovered 79 returning short period comets during her career, in 1975, she also co-discovered Themisto, one of the 67 moons of Jupiter. The inner main-belt asteroid 1657 Roemera, discovered by Swiss astronomer Paul Wild in 1961, was named in her honor, lunar and Planetary Laboratory, Elizabeth Roemer
32.
US Naval Observatory Flagstaff Station
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The United States Naval Observatory Flagstaff Station, is an astronomical observatory near Flagstaff, Arizona, USA. It is the national dark-sky observing facility under the United States Naval Observatory, NOFS and USNO combine as the Celestial Reference Frame manager for the U. S. Secretary of Defense. NOFS science supports every aspect of astronomy to some level, providing national support. Work at NOFS covers the gamut of astrometry and astrophysics in order to facilitate its production of accurate/precise astronomical catalogs, multiple observations of each object may themselves take weeks, months or years, by themselves. The United States Naval Observatory, Flagstaff Station celebrated its 50th anniversary of the move there from Washington, dr. John Hall, Director of the Naval Observatorys Equatorial Division from 1947, founded NOFS. Dr. Art Hoag became its first director in 1955, both later were to become directors of nearby Lowell Observatory. NOFS remains active in supporting regional dark skies, both to support its national mission, and to promote and protect a national resource legacy for generations of humans to come. Indeed, despite a history, NOFS has a rich heritage which is derived from its parent organization, USNO. Navy since it saw first light in 1964 and this status will change when the NPOI four 1. 8-meter telescopes see their own first light in the near future. KSAR rides in the arms of a fork mount. The telescope is used in both the spectrum, and in the near infrared, the latter using a sub-30-Kelvin, helium-refrigerated, InSb camera. In 1978, the 1. 55-m telescope was used to discover the moon of dwarf planet Pluto, the Charon discovery led to mass calculations which ultimately revealed how tiny Pluto was, and eventually caused the IAU to reclassify Pluto as a dwarf planet. The 1. 55-meter telescope was used to observe and track NASAs Deep Impact Spacecraft, as it navigated to a successful inter-planetary impact with the celebrated Comet 9p/Tempel. The 61 dome is located on NOFS grounds, with support. The large vacuum coating chamber facility is located in this complex. A dielectric coating capability has also been demonstrated, large optics and telescope components can be moved about NOFS using its suite of cranes, lifts, cargo elevators and specialized carts. The KSAR Telescopes 60-foot diameter steel dome is large for the telescopes aperture. It uses a very wide 2-shutter, vertical slit. 6-meters, by using fast, however, the 61-inch telescope remains unique in its ability to operationally conduct both very high-accuracy relative astrometry to the milliarcsecond level, and close-separation, PSF photometry
33.
Arizona
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Arizona is a state in the southwestern region of the United States. It is also part of the Western United States and the Mountain West states and it is the sixth largest and the 14th most populous of the 50 states. Its capital and largest city is Phoenix, Arizona is one of the Four Corners states. It has borders with New Mexico, Utah, Nevada, California, and Mexico, Arizonas border with Mexico is 389 miles long, on the northern border of the Mexican states of Sonora and Baja California. Arizona is the 48th state and last of the states to be admitted to the Union. Historically part of the territory of Alta California in New Spain, after being defeated in the Mexican–American War, Mexico ceded much of this territory to the United States in 1848. The southernmost portion of the state was acquired in 1853 through the Gadsden Purchase, Southern Arizona is known for its desert climate, with very hot summers and mild winters. There are ski resorts in the areas of Flagstaff, Alpine, in addition to the Grand Canyon National Park, there are several national forests, national parks, and national monuments. To the European settlers, their pronunciation sounded like Arissona, the area is still known as alĭ ṣonak in the Oodham language. Another possible origin is the Basque phrase haritz ona, as there were numerous Basque sheepherders in the area, There is a misconception that the states name originated from the Spanish term Árida Zona. See also lists of counties, islands, rivers, lakes, state parks, national parks, Arizona is in the Southwestern United States as one of the Four Corners states. Arizona is the sixth largest state by area, ranked after New Mexico, of the states 113,998 square miles, approximately 15% is privately owned. The remaining area is public forest and park land, state trust land, Arizona is well known for its desert Basin and Range region in the states southern portions, which is rich in a landscape of xerophyte plants such as the cactus. This regions topography was shaped by volcanism, followed by the cooling-off. Its climate has hot summers and mild winters. The state is well known for its pine-covered north-central portion of the high country of the Colorado Plateau. Like other states of the Southwest United States, Arizona has an abundance of mountains, despite the states aridity, 27% of Arizona is forest, a percentage comparable to modern-day France or Germany. The worlds largest stand of pine trees is in Arizona
34.
Short-period comet
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A comet is an icy small Solar System body that, when passing close to the Sun, warms and begins to evolve gasses, a process called outgassing. This produces an atmosphere or coma, and sometimes also a tail. These phenomena are due to the effects of radiation and the solar wind acting upon the nucleus of the comet. Comet nuclei range from a few hundred metres to tens of kilometres across and are composed of collections of ice, dust. The coma may be up to 15 times the Earths diameter, if sufficiently bright, a comet may be seen from the Earth without the aid of a telescope and may subtend an arc of 30° across the sky. Comets have been observed and recorded since ancient times by many cultures, Comets usually have highly eccentric elliptical orbits, and they have a wide range of orbital periods, ranging from several years to potentially several millions of years. Short-period comets originate in the Kuiper belt or its associated scattered disc, long-period comets are thought to originate in the Oort cloud, a spherical cloud of icy bodies extending from outside the Kuiper belt to halfway to the nearest star. Long-period comets are set in motion towards the Sun from the Oort cloud by gravitational perturbations caused by passing stars, hyperbolic comets may pass once through the inner Solar System before being flung to interstellar space. The appearance of a comet is called an apparition, Comets are distinguished from asteroids by the presence of an extended, gravitationally unbound atmosphere surrounding their central nucleus. This atmosphere has parts termed the coma and the tail, however, extinct comets that have passed close to the Sun many times have lost nearly all of their volatile ices and dust and may come to resemble small asteroids. Asteroids are thought to have a different origin from comets, having formed inside the orbit of Jupiter rather than in the outer Solar System, the discovery of main-belt comets and active centaur minor planets has blurred the distinction between asteroids and comets. As of November 2014 there are 5,253 known comets, however, this represents only a tiny fraction of the total potential comet population, as the reservoir of comet-like bodies in the outer Solar System is estimated to be one trillion. Roughly one comet per year is visible to the eye, though many of those are faint. Particularly bright examples are called Great Comets, the word comet derives from the Old English cometa from the Latin comēta or comētēs. That, in turn, is a latinisation of the Greek κομήτης, Κομήτης was derived from κομᾶν, which was itself derived from κόμη and was used to mean the tail of a comet. The astronomical symbol for comets is ☄, consisting of a disc with three hairlike extensions. The solid, core structure of a comet is known as the nucleus, cometary nuclei are composed of an amalgamation of rock, dust, water ice, and frozen gases such as carbon dioxide, carbon monoxide, methane, and ammonia. As such, they are described as dirty snowballs after Fred Whipples model
35.
Apparent magnitude
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The apparent magnitude of a celestial object is a number that is a measure of its brightness as seen by an observer on Earth. The brighter an object appears, the lower its magnitude value, the Sun, at apparent magnitude of −27, is the brightest object in the sky. It is adjusted to the value it would have in the absence of the atmosphere, furthermore, the magnitude scale is logarithmic, a difference of one in magnitude corresponds to a change in brightness by a factor of 5√100, or about 2.512. The measurement of apparent magnitudes or brightnesses of celestial objects is known as photometry, apparent magnitudes are used to quantify the brightness of sources at ultraviolet, visible, and infrared wavelengths. An apparent magnitude is measured in a specific passband corresponding to some photometric system such as the UBV system. In standard astronomical notation, an apparent magnitude in the V filter band would be denoted either as mV or often simply as V, the scale used to indicate magnitude originates in the Hellenistic practice of dividing stars visible to the naked eye into six magnitudes. The brightest stars in the sky were said to be of first magnitude, whereas the faintest were of sixth magnitude. Each grade of magnitude was considered twice the brightness of the following grade and this rather crude scale for the brightness of stars was popularized by Ptolemy in his Almagest, and is generally believed to have originated with Hipparchus. This implies that a star of magnitude m is 2.512 times as bright as a star of magnitude m +1 and this figure, the fifth root of 100, became known as Pogsons Ratio. The zero point of Pogsons scale was defined by assigning Polaris a magnitude of exactly 2. However, with the advent of infrared astronomy it was revealed that Vegas radiation includes an Infrared excess presumably due to a disk consisting of dust at warm temperatures. At shorter wavelengths, there is negligible emission from dust at these temperatures, however, in order to properly extend the magnitude scale further into the infrared, this peculiarity of Vega should not affect the definition of the magnitude scale. Therefore, the scale was extrapolated to all wavelengths on the basis of the black body radiation curve for an ideal stellar surface at 11000 K uncontaminated by circumstellar radiation. On this basis the spectral irradiance for the zero magnitude point, with the modern magnitude systems, brightness over a very wide range is specified according to the logarithmic definition detailed below, using this zero reference. In practice such apparent magnitudes do not exceed 30, astronomers have developed other photometric zeropoint systems as alternatives to the Vega system. The AB magnitude zeropoint is defined such that an objects AB, the dimmer an object appears, the higher the numerical value given to its apparent magnitude, with a difference of 5 magnitudes corresponding to a brightness factor of exactly 100. Since an increase of 5 magnitudes corresponds to a decrease in brightness by a factor of exactly 100, each magnitude increase implies a decrease in brightness by the factor 5√100 ≈2.512. Inverting the above formula, a magnitude difference m1 − m2 = Δm implies a brightness factor of F2 F1 =100 Δ m 5 =100.4 Δ m ≈2.512 Δ m
36.
Tenerife
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Tenerife is the largest and most populated island of the seven Canary Islands. It is also the most populated island of Spain, with an area of 2,034.38 square kilometres and 898,680 inhabitants,43 percent of the total population of the Canary Islands. Tenerife is the largest and most populous island of Macaronesia, about five million tourists visit Tenerife each year, the most of any of the Canary Islands. It is one of the most important tourist destinations in Spain, Tenerife hosts one of the worlds largest carnivals and the Carnival of Santa Cruz de Tenerife is working to be designated as a UNESCO World Heritage Site. Served by two airports, Tenerife North Airport and Tenerife South Airport, Tenerife is the centre of the archipelago. The 1977 collision of two Boeing 747 passenger jets at Tenerife North Airport, resulting in 583 deaths, remains the deadliest aviation accident in world history, Santa Cruz de Tenerife is the capital of the island and the seat of the island council. The city is capital of the community of Canary Islands, sharing governmental institutions such as Presidency. Between the 1833 territorial division of Spain and 1927, Santa Cruz de Tenerife was the capital of the Canary Islands. In 1927 the Crown ordered that the capital of the Canary Islands be shared, Santa Cruz contains the modern Auditorio de Tenerife, the architectural symbol of the Canary Islands. The island is home to the University of La Laguna, founded in 1792 in San Cristóbal de La Laguna, a UNESCO World Heritage Site, the city is the second to have been founded on the island, and is the third of the archipelago. The city of La Laguna was capital of the Canary Islands before Santa Cruz replaced it in 1833, also located on the island, Macizo de Anaga since 2015 has been designated as a UNESCO Biosphere Reserve. It has the largest number of species in Europe. The islands indigenous people, the Guanches, referred to the island as Achinet or Chenet in their language. According to Pliny the Younger, Berber king Juba II sent an expedition to the Canary Islands and Madeira, he named the Canary Islands for the particularly ferocious dogs on the island. Juba II and Ancient Romans referred to the island of Tenerife as Nivaria, derived from the Latin word nix, meaning snow, the Benahoaritas are said to have named the island, deriving it from the words tene and ife. After colonisation, the Hispanisation of the resulted in adding the letter r to unite both words, producing Tenerife. He ruled the island in the days before the conquest of the Canary Islands by Castilla. The formal demonym used to refer to the people of Tenerife is Tinerfeño/a, in modern society, the latter term is generally applied only to inhabitants of the capital, Santa Cruz
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Canary Islands
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The Canary Islands, also known as the Canaries, are an archipelago and autonomous community of Spain located on the Atlantic Ocean,100 kilometres west of Morocco. The Canaries are among the outermost regions of the European Union proper and it is also one of the eight regions with special consideration of historical nationality recognized as such by the Spanish Government. The main islands are Tenerife, Fuerteventura, Gran Canaria, Lanzarote, La Palma, La Gomera, the archipelago also includes a number of islands and islets, La Graciosa, Alegranza, Isla de Lobos, Montaña Clara, Roque del Oeste and Roque del Este. In ancient times, the chain was often referred to as the Fortunate Isles. The Canary Islands is the most southerly region of Spain and the largest and most populated archipelago of the Macaronesia region, the islands have a subtropical climate, with long hot summers and moderately warm winters. The precipitation levels and the level of maritime moderation varies depending on location and elevation, green areas as well as desert exist on the archipelago. Due to their location above the inversion layer, the high mountains of these islands are ideal for astronomical observation. For this reason, two professional observatories, Teide Observatory on the island of Tenerife and Roque de los Muchachos Observatory on the island of La Palma, have built on the islands. Las Palmas de Gran Canaria has been the largest city in the Canaries since 1768, between the 1833 territorial division of Spain and 1927 Santa Cruz de Tenerife was the sole capital of the Canary Islands. In 1927 a decree ordered that the capital of the Canary Islands be shared, the third largest city of the Canary Islands is San Cristóbal de La Laguna on Tenerife. This city is home to the Consejo Consultivo de Canarias. During the time of the Spanish Empire, the Canaries were the main stopover for Spanish galleons on their way to the Americas, who came south to catch the prevailing northeasterly trade winds. The name Islas Canarias is likely derived from the Latin name Canariae Insulae, meaning Islands of the Dogs, according to the historian Pliny the Elder, the Mauretanian king Juba II named the island Canaria because it contained vast multitudes of dogs of very large size. Another speculation is that the dogs were actually a species of monk seal, critically endangered. The dense population of seals may have been the characteristic that most struck the few ancient Romans who established contact with these islands by sea. Alternatively, it is said that the inhabitants of the island, Guanches, used to worship dogs, mummified them. The ancient Greeks also knew about a people, living far to the west, who are the dog-headed ones, who worshipped dogs on an island. Some hypothesize that the Canary Islands dog-worship and the ancient Egyptian cult of the god, Anubis are closely connected
38.
Barcelona
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Founded as a Roman city, in the Middle Ages Barcelona became the capital of the County of Barcelona. Barcelona has a cultural heritage and is today an important cultural centre. Particularly renowned are the works of Antoni Gaudí and Lluís Domènech i Montaner. The headquarters of the Union for the Mediterranean is located in Barcelona, the city is known for hosting the 1992 Summer Olympics as well as world-class conferences and expositions and also many international sport tournaments. It is a cultural and economic centre in southwestern Europe, 24th in the world. In 2008 it was the fourth most economically powerful city by GDP in the European Union, in 2012 Barcelona had a GDP of $170 billion, it is leading Spain in both employment rate and GDP per capita change. In 2009 the city was ranked Europes third and one of the worlds most successful as a city brand, since 2011 Barcelona has been a leading smart city in Europe. During the Middle Ages, the city was known as Barchinona, Barçalona, Barchelonaa. Internationally, Barcelonas name is abbreviated to Barça. However, this refers only to FC Barcelona, the football club. The common abbreviated form used by locals is Barna, another common abbreviation is BCN, which is also the IATA airport code of the Barcelona-El Prat Airport. The city is referred to as the Ciutat Comtal in Catalan. The origin of the earliest settlement at the site of present-day Barcelona is unclear, the ruins of an early settlement have been excavated in the El Raval neighbourhood, including different tombs and dwellings dating to earlier than 5000 BC. The founding of Barcelona is the subject of two different legends, the first attributes the founding of the city to the mythological Hercules. In about 15 BC, the Romans redrew the town as a castrum centred on the Mons Taber, under the Romans, it was a colony with the surname of Faventia, or, in full, Colonia Faventia Julia Augusta Pia Barcino or Colonia Julia Augusta Faventia Paterna Barcino. It enjoyed immunity from imperial burdens, the city minted its own coins, some from the era of Galba survive. Some remaining fragments of the Roman walls have incorporated into the cathedral. The cathedral, also known as the Basilica La Seu, is said to have founded in 343
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Naked eye
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Naked eye, also called bare eye or unaided eye, is the practice of engaging in visual perception unaided by a magnifying or light-collecting optical device, such as a telescope or microscope. Vision corrected to normal acuity using corrective lenses is considered naked, in astronomy, the naked eye may be used to observe events that can be viewed without equipment, such as an astronomical conjunction, the passage of a comet, or a meteor shower. Sky lore and various tests demonstrate a wealth of phenomena that can be seen with the unaided eye. The basic accuracies of the eye are, Quick autofocus from distances of 25 cm to 50 cm to infinity. Angular resolution, about 1 arcminute, approximately 0. 02° or 0.0003 radians, field of view, simultaneous visual perception in an area of about 160° × 175°. Faint stars up to +8 magnitude under a dark sky. Photometry to ±10% or 1% of intensity – in a range between night and day of 1,10,000,000,000, symmetries of 10–20, see the measurements of Tycho Brahe and the Egyptians. Even a few hundred kilometers away from an area where the sky can appear to be very dark. For most people, these are likely to be the best observing conditions within their reach, under such typical dark sky conditions, the naked eye can see stars with an apparent magnitude up to +6m. Under perfect dark sky conditions where all light pollution is absent, the angular resolution of the naked eye is about 1′, however, some people have sharper vision than that. There is anecdotal evidence that people had seen the Galilean moons of Jupiter before telescopes were invented, Uranus, when discovered in 1781, was the first planet discovered using technology rather than being spotted by the naked eye. In practice, the extinction and dust reduces this number somewhat. In the center of a city, where the limiting magnitude due to extreme amounts of light pollution can be +4m or less. Colors can be seen but this is limited by the fact that the eye uses rods instead of cones to view fainter stars, the visibility of diffuse objects such as star clusters and galaxies is much more strongly affected by light pollution than is that of planets and stars. Under typical dark conditions only a few objects are visible. The Triangulum Galaxy is a difficult averted vision object and only visible at all if it is higher than 50° in the sky, the globular clusters M3 in Canes Venatici and M92 in Hercules are also visible with the naked eye under such conditions. Under really dark sky conditions, however, M33 is easy to see, many other Messier objects are also visible under such conditions. The most distant objects that have seen by the naked eye are nearby bright galaxies such as Centaurus A, Bodes Galaxy, Sculptor Galaxy
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Perseus (constellation)
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Perseus is a constellation in the northern sky, being named after the Greek mythological hero Perseus. It is one of the 48 listed by the 2nd-century astronomer Ptolemy and it is located near several other constellations named after ancient Greek legends surrounding Perseus, including Andromeda to the west and Cassiopeia to the north. Perseus is also bordered by Aries and Taurus to the south, Auriga to the east, Camelopardalis to the north, the galactic plane of the Milky Way passes through Perseus, whose brightest star is the yellow-white supergiant Alpha Persei, which shines at magnitude 1.79. It and many of the stars are members of an open cluster known as the Alpha Persei Cluster. The best-known star, however, is Algol, linked with ominous legends because of its variability, rather than being an intrinsically variable star, it is an eclipsing binary. Other notable star systems in Perseus include X Persei, a system containing a neutron star, and GK Persei. The Double Cluster, comprising two open clusters quite near each other in the sky, was known to the ancient Chinese, the constellation gives its name to the Perseus cluster, a massive galaxy cluster located 250 million light-years from Earth. It hosts the radiant of the annual Perseids meteor shower—one of the most prominent meteor showers in the sky, the constellation of Perseus may be derived from the Babylonian Old Man constellation, then associated with East in the MUL. APIN—an astronomical compilation dating to around 1000 BCE. In Greek mythology, Perseus was the son of Danaë, who was sent by King Polydectes to bring the head of Medusa the Gorgon—whose visage caused all who gazed upon her to turn to stone—as a wedding gift. Perseus slew Medusa in her sleep, and Pegasus and Chrysaor appeared from her body, Perseus continued to the realm of Cepheus whose daughter Andromeda was to be sacrificed to Cetus the sea monster. Perseus rescued Andromeda from the monster by killing it with his diamond sword and he turned Polydectes and his followers to stone with Medusas head and appointed Dictys the fisherman king. Perseus and Andromeda married and had six children, in the sky, Perseus lies near the constellations Andromeda, Cepheus, Cassiopeia, Cetus, and Pegasus. Four Chinese constellations are contained in the area of the sky identified with Perseus in the West, incorporating stars from the northern part of the constellation, it contained Mu, Delta, Psi, Alpha, Gamma and Eta Persei. Lambda and possibly Mu Persei lay within it, dàlíng, the Great Trench, was the fifth paranatellon of that house, representing the trenches where criminals executed en masse in August were interred. It was formed by Kappa, Omega, Rho,24,17 and 15 Persei, the pile of corpses prior to their interment was represented by Jīshī, the sixth paranatellon of the house. The Double Cluster, h and Chi Persei, had special significance in Chinese astronomy, known as Hsi and Ho, the two clusters represented two astronomers who failed to predict a total solar eclipse and were subsequently beheaded. In Polynesia, Perseus was not commonly recognized as a constellation, the only people that named it were those of the Society Islands. Algol may have been named Matohi by the Māori people, Matohi occasionally came into conflict with Tangaroa-whakapau over which of them should appear in the sky, the outcome affecting the tides
41.
Opposition (planets)
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In positional astronomy, two celestial bodies are said to be in opposition when they are on opposite sides of the sky, viewed from a given place. A planet is said to be in opposition when it is in opposition to the Sun, opposition occurs only in superior planets. The instant of opposition is defined as that when the apparent geocentric longitude of the body differs by 180° from the apparent geocentric longitude of the Sun. When it is in opposition, a lunar eclipse occurs. The astronomical symbol for opposition is ☍, handwritten, As seen from a planet that is superior, an inferior planet on the opposite side of the Sun is in superior conjunction with the Sun. An inferior conjunction occurs when the two lie in a line on the same side of the Sun. At inferior conjunction, the planet is in opposition to the Sun as seen from the inferior planet. Conjunction Positional astronomy Syzygy Asteroids around opposition – British Astronomical Association - Computing Section
42.
Comet nucleus
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The nucleus is the solid, central part of a comet, popularly termed a dirty snowball or an icy dirtball. A cometary nucleus is composed of rock, dust, and frozen gases, when heated by the Sun, the gases sublimate and produce an atmosphere surrounding the nucleus known as the coma. The force exerted on the coma by the Suns radiation pressure and solar wind cause an enormous tail to form, a typical comet nucleus has an albedo of 0.04. This is blacker than coal, and may be caused by a covering of dust, comets, or their precursors, formed in the outer Solar System, possibly millions of years before planet formation. How and when formed is debated, with distinct implications for Solar System formation, dynamics. Three-dimensional computer simulations indicate the structural features observed on cometary nuclei can be explained by pairwise low velocity accretion of weak cometesimals. The currently favored creation mechanism is that of the nebular hypothesis, astronomers think that comets originate in both the Oort cloud and the scattered disk. Most cometary nuclei are thought to be no more than about 10 miles across, the largest comets that have come inside the orbit of Saturn are C/2002 VQ94, Hale–Bopp, 29P, 109P/Swift–Tuttle, and 28P/Neujmin. The potato-shaped nucleus of Halleys comet contains equal amounts of ice, during a flyby in September 2001, the Deep Space 1 spacecraft observed the nucleus of Comet Borrelly and found it to be about half the size of the nucleus of Halleys Comet. Borrellys nucleus was also potato-shaped and had a black surface. Like Halleys Comet, Comet Borrelly only released gas from small areas where holes in the crust exposed the ice to sunlight, the nucleus of comet Hale–Bopp was estimated to be 60 ±20 km in diameter. Hale-Bopp appeared bright to the eye because its unusually large nucleus gave off a great deal of dust. The nucleus of P/2007 R5 is probably only 100–200 meters in diameter, the largest centaurs are estimated to be 250 km to 300 km in diameter. Three of the largest would include 10199 Chariklo,2060 Chiron, known comets have been estimated to have an average density of 0.6 g/cm3. Below is a list of comets that have had estimated sizes, densities, about 80% of the Halleys Comet nucleus is water ice, and frozen carbon monoxide makes up another 15%. Much of the remainder is carbon dioxide, methane. Scientists think that comets are chemically similar to Halleys Comet. The nucleus of Halleys Comet is also a dark black
. Bibcode:2009A&A...495..975A. doi:10.1051/0004-6361:200810458.
