1.
Lincoln Near-Earth Asteroid Research
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LINEAR was responsible for the majority of asteroid discoveries from 1998 until it was overtaken by the Catalina Sky Survey in 2005. As of 15 September 2011, LINEAR had detected 231,082 new small Solar System bodies, the instruments used by the LINEAR program are located at Lincoln Laboratorys Experimental Test Site on the White Sands Missile Range near Socorro, New Mexico. In the late 1970s, the new Lincoln Laboratorys Experimental Test Site facility was built at White Sands Missile Range, the projects prototype used low-light video cameras. In 1994 a new proposal was made for automated detection of asteroids, the wide-field Air Force telescopes were designed for optical observation of Earth-orbiting spacecraft. Initial field tests used a 1024 ×1024 pixel charge-coupled device detector, while this CCD detector filled only about one fifth of the telescopes field of view, four near-earth objects were discovered. A1960 ×2560 pixel CCD which covered the telescopes two-square degree field of view was then installed, the first LINEAR telescope became fully operational in March 1998. Beginning in October 1999, a second 1.0 m telescope was added to the search effort, in 2002, a 0.5 m telescope equipped with the original CCD was brought on-line to provide follow-up observations for the discoveries made by the two search telescopes. This allowed about 20% more of the sky to be searched each night, data recorded by the telescopes is sent to a Lincoln Laboratory facility at Hanscom Air Force Base in Lexington, Massachusetts for processing. Detections are then forwarded to the Minor Planet Center, other objects discovered include 1999 AN10,2002 TD66, and 2004 FH. Stokes, Frank Shelly, Herbert E. M. Viggh, Matthew S. Blythe, and Joseph S. Stuart Near Earth Object program – discovery statistics, Jet Propulsion Laboratory
2.
Minor planet
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A minor planet is an astronomical object in direct orbit around the Sun that is neither a planet nor exclusively classified as a comet. Minor planets can be dwarf planets, asteroids, trojans, centaurs, Kuiper belt objects, as of 2016, the orbits of 709,706 minor planets were archived at the Minor Planet Center,469,275 of which had received permanent numbers. The first minor planet to be discovered was Ceres in 1801, the term minor planet has been used since the 19th century to describe these objects. The term planetoid has also used, especially for larger objects such as those the International Astronomical Union has called dwarf planets since 2006. Historically, the asteroid, minor planet, and planetoid have been more or less synonymous. This terminology has become complicated by the discovery of numerous minor planets beyond the orbit of Jupiter. A Minor planet seen releasing gas may be classified as a comet. Before 2006, the IAU had officially used the term minor planet, during its 2006 meeting, the IAU reclassified minor planets and comets into dwarf planets and small Solar System bodies. Objects are called dwarf planets if their self-gravity is sufficient to achieve hydrostatic equilibrium, all other minor planets and comets are called small Solar System bodies. The IAU stated that the minor planet may still be used. However, for purposes of numbering and naming, the distinction between minor planet and comet is still used. Hundreds of thousands of planets have been discovered within the Solar System. The Minor Planet Center has documented over 167 million observations and 729,626 minor planets, of these,20,570 have official names. As of March 2017, the lowest-numbered unnamed minor planet is 1974 FV1, as of March 2017, the highest-numbered named minor planet is 458063 Gustavomuler. There are various broad minor-planet populations, Asteroids, traditionally, most have been bodies in the inner Solar System. Near-Earth asteroids, those whose orbits take them inside the orbit of Mars. Further subclassification of these, based on distance, is used, Apohele asteroids orbit inside of Earths perihelion distance. Aten asteroids, those that have semi-major axes of less than Earths, Apollo asteroids are those asteroids with a semimajor axis greater than Earths, while having a perihelion distance of 1.017 AU or less. Like Aten asteroids, Apollo asteroids are Earth-crossers, amor asteroids are those near-Earth asteroids that approach the orbit of Earth from beyond, but do not cross it
3.
Near-Earth object
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A near-Earth object is any small Solar System body whose orbit brings it into proximity with Earth. By definition, a solar system body is a NEO if its closest approach to the Sun is less than 1.3 astronomical unit and it is now widely accepted that collisions in the past have had a significant role in shaping the geological and biological history of the Earth. NEOs have become of increased interest since the 1980s because of increased awareness of the potential danger some of the asteroids or comets pose, and mitigations are being researched. In January 2016, NASA announced the Planetary Defense Coordination Office to track NEOs larger than 30 to 50 meters in diameter and coordinate an effective threat response, NEAs have orbits that lie partly between 0.983 and 1.3 AU away from the Sun. When a NEA is detected it is submitted to the IAUs Minor Planet Center for cataloging, some NEAs orbits intersect that of Earths so they pose a collision danger. The United States, European Union, and other nations are currently scanning for NEOs in an effort called Spaceguard. In the United States and since 1998, NASA has a mandate to catalogue all NEOs that are at least 1 kilometer wide. In 2006, it was estimated that 20% of the objects had not yet been found. In 2011, largely as a result of NEOWISE, it was estimated that 93% of the NEAs larger than 1 km had been found, as of 5 February 2017, there have been 875 NEAs larger than 1 km discovered, of which 157 are potentially hazardous. The inventory is much less complete for smaller objects, which still have potential for scale, though not global. Potentially hazardous objects are defined based on parameters that measure the objects potential to make threatening close approaches to the Earth. Mostly objects with an Earth minimum orbit intersection distance of 0.05 AU or less, objects that cannot approach closer to the Earth than 0.05 AU, or are smaller than about 150 m in diameter, are not considered PHOs. This makes them a target for exploration. As of 2016, three near-Earth objects have been visited by spacecraft, more recently, a typical frame of reference for looking at NEOs has been through the scientific concept of risk. In this frame, the risk that any near-Earth object poses is typically seen through a lens that is a function of both the culture and the technology of human society, NEOs have been understood differently throughout history. Each time an NEO is observed, a different risk was posed and it is not just a matter of scientific knowledge. Such perception of risk is thus a product of religious belief, philosophic principles, scientific understanding, technological capabilities, and even economical resourcefulness.03 E −0.4 megatonnes. For instance, it gives the rate for bolides of 10 megatonnes or more as 1 per thousand years, however, the authors give a rather large uncertainty, due in part to uncertainties in determining the energies of the atmospheric impacts that they used in their determination
4.
Potentially hazardous object
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A potentially hazardous object can be known not to be a threat to Earth for the next 100 years or more, if its orbit is reasonably well determined. Potentially hazardous asteroids with some threat of impacting Earth in the next 100 years are listed on the Sentry Risk Table, as of March 2017 there are 1,786 known potentially hazardous asteroids and only 205 have an observation arc shorter than 30 days. Of the known PHAs,157 are believed to be larger than one kilometer in diameter, a calculated diameter is only a rough estimate, as it is inferred from the objects varying brightness—observed and measured at various times—and the assumed, yet unknown reflectivity of its surface. Most of the discovered PHAs are Apollo asteroids and fewer belong to the group of Aten asteroids, after several astronomical surveys, the number of known PHAs has increased tenfold since the end of the 1990s. These surveys have led to a number of 15,802 discovered near-Earth objects. Most of them are asteroids, with just some 106 near-Earth comets, the Minor Planet Centers website Unusual Minor Planets also publishes detailed statistics for these objects. This is big enough to cause devastation to human settlements unprecedented in human history in the case of a land impact. Such impact events occur on average once per 10,000 years. NEOWISE data estimates that there are 4,700 ±1,500 potentially hazardous asteroids with a greater than 100 meters. As of 2012, an estimated 20 to 30 percent of these objects have been found, Asteroids larger than 35 meters across can pose a threat to a town or city. The diameter of most small asteroids is not well determined and can only be estimated based on their brightness, for this reason NASA and the Jet Propulsion Laboratory use the more practical measure of absolute magnitude. Any asteroid with a magnitude of 22. The NASA near-Earth object program uses an assumed albedo of 0.13 for this purpose, in May 2016, the asteroid size estimates arising from the Wide-field Infrared Survey Explorer and NEOWISE missions have been questioned, but the criticism has yet to undergo peer review. Several astronomical survey projects such as Lincoln Near-Earth Asteroid Research and Catalina Sky Survey continue to search for more PHOs, both professional and amateur astronomers participate in such monitoring. This is a reflection of the character of the Solar System. The two main scales used to categorize the impact hazards of asteroids are the Palermo Technical Impact Hazard Scale, the lowest numbered PHA is 1566 Icarus. The largest known Potentially hazardous asteroid is 1999 JM8 with a diameter of ~7 km, below is listed the largest PHA discovered in a given year. Historical data of the number of discovered PHA since 1999 are displayed in the bar charts—one for the total number
5.
Apollo asteroid
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The Apollo asteroids are a group of near-Earth asteroids named after 1862 Apollo, discovered by German astronomer Karl Reinmuth in the 1930s. They are Earth crossing asteroids that have an orbital semi-major axis greater than that of the Earth, as of November 2016, the steadily growing number of known Apollo asteroids has reached a total of 8,180 members. It is by far the largest group of objects, compared to the Aten, Amor. Currently, there are 1,133 numbered Apollos, asteroids are not numbered until they have been observed at two or more oppositions. There are also 1,472 Apollo asteroids that are enough. The closer their semi-major axis is to Earths, the eccentricity is needed for the orbits to cross. The largest known Apollo asteroid is 1866 Sisyphus, with a diameter of about 8.5 km, examples of known Apollo asteroids include, Apollo asteroids Apollo asteroid records List of Apollo minor planets
6.
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
7.
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
8.
Orders of magnitude (length)
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The following are examples of orders of magnitude for different lengths. To help compare different orders of magnitude, the following list describes various lengths between 1. 6×10−35 meters and 101010122 meters,100 pm –1 Ångström 120 pm – radius of a gold atom 150 pm – Length of a typical covalent bond. 280 pm – Average size of the water molecule 298 pm – radius of a caesium atom, light travels 1 metre in 1⁄299,792,458, or 3. 3356409519815E-9 of a second. 25 metres – wavelength of the broadcast radio shortwave band at 12 MHz 29 metres – height of the lighthouse at Savudrija, Slovenia. 31 metres – wavelength of the broadcast radio shortwave band at 9.7 MHz 34 metres – height of the Split Point Lighthouse in Aireys Inlet, Victoria, Australia. 1 kilometre is equal to,1,000 metres 0.621371 miles 1,093.61 yards 3,280.84 feet 39,370.1 inches 100,000 centimetres 1,000,000 millimetres Side of a square of area 1 km2. Radius of a circle of area π km2,1.637 km – deepest dive of Lake Baikal in Russia, the worlds largest fresh water lake. 2.228 km – height of Mount Kosciuszko, highest point in Australia Most of Manhattan is from 3 to 4 km wide, farsang, a modern unit of measure commonly used in Iran and Turkey. Usage of farsang before 1926 may be for a precise unit derived from parasang. It is the altitude at which the FAI defines spaceflight to begin, to help compare orders of magnitude, this page lists lengths between 100 and 1,000 kilometres. 7.9 Gm – Diameter of Gamma Orionis 9, the newly improved measurement was 30% lower than the previous 2007 estimate. The size was revised in 2012 through improved measurement techniques and its faintness gives us an idea how our Sun would appear when viewed from even so close a distance as this. 350 Pm –37 light years – Distance to Arcturus 373.1 Pm –39.44 light years - Distance to TRAPPIST-1, a star recently discovered to have 7 planets around it. 400 Pm –42 light years – Distance to Capella 620 Pm –65 light years – Distance to Aldebaran This list includes distances between 1 and 10 exametres. 13 Em –1,300 light years – Distance to the Orion Nebula 14 Em –1,500 light years – Approximate thickness of the plane of the Milky Way galaxy at the Suns location 30.8568 Em –3,261. At this scale, expansion of the universe becomes significant, Distance of these objects are derived from their measured redshifts, which depends on the cosmological models used. At this scale, expansion of the universe becomes significant, Distance of these objects are derived from their measured redshifts, which depends on the cosmological models used. 590 Ym –62 billion light years – Cosmological event horizon, displays orders of magnitude in successively larger rooms Powers of Ten Travel across the Universe
9.
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
10.
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
11.
Mean anomaly
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In celestial mechanics, the mean anomaly is an angle used in calculating the position of a body in an elliptical orbit in the classical two-body problem. Define T as the time required for a body to complete one orbit. In time T, the radius vector sweeps out 2π radians or 360°. The average rate of sweep, n, is then n =2 π T or n =360 ∘ T, define τ as the time at which the body is at the pericenter. From the above definitions, a new quantity, M, the mean anomaly can be defined M = n, because the rate of increase, n, is a constant average, the mean anomaly increases uniformly from 0 to 2π radians or 0° to 360° during each orbit. It is equal to 0 when the body is at the pericenter, π radians at the apocenter, if the mean anomaly is known at any given instant, it can be calculated at any later instant by simply adding n δt where δt represents the time difference. Mean anomaly does not measure an angle between any physical objects and it is simply a convenient uniform measure of how far around its orbit a body has progressed since pericenter. The mean anomaly is one of three parameters that define a position along an orbit, the other two being the eccentric anomaly and the true anomaly. Define l as the longitude, the angular distance of the body from the same reference direction. Thus mean anomaly is also M = l − ϖ, mean angular motion can also be expressed, n = μ a 3, where μ is a gravitational parameter which varies with the masses of the objects, and a is the semi-major axis of the orbit. Mean anomaly can then be expanded, M = μ a 3, and here mean anomaly represents uniform angular motion on a circle of radius a
12.
Degree (angle)
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A degree, usually denoted by °, is a measurement of a plane angle, defined so that a full rotation is 360 degrees. It is not an SI unit, as the SI unit of measure is the radian. Because a full rotation equals 2π radians, one degree is equivalent to π/180 radians, the original motivation for choosing the degree as a unit of rotations and angles is unknown. One theory states that it is related to the fact that 360 is approximately the number of days in a year. Ancient astronomers noticed that the sun, which follows through the path over the course of the year. Some ancient calendars, such as the Persian calendar, used 360 days for a year, the use of a calendar with 360 days may be related to the use of sexagesimal numbers. The earliest trigonometry, used by the Babylonian astronomers and their Greek successors, was based on chords of a circle, a chord of length equal to the radius made a natural base quantity. One sixtieth of this, using their standard sexagesimal divisions, was a degree, Aristarchus of Samos and Hipparchus seem to have been among the first Greek scientists to exploit Babylonian astronomical knowledge and techniques systematically. Timocharis, Aristarchus, Aristillus, Archimedes, and Hipparchus were the first Greeks known to divide the circle in 360 degrees of 60 arc minutes, eratosthenes used a simpler sexagesimal system dividing a circle into 60 parts. Furthermore, it is divisible by every number from 1 to 10 except 7 and this property has many useful applications, such as dividing the world into 24 time zones, each of which is nominally 15° of longitude, to correlate with the established 24-hour day convention. Finally, it may be the case more than one of these factors has come into play. For many practical purposes, a degree is a small enough angle that whole degrees provide sufficient precision. When this is not the case, as in astronomy or for geographic coordinates, degree measurements may be written using decimal degrees, with the symbol behind the decimals. Alternatively, the sexagesimal unit subdivisions can be used. One degree is divided into 60 minutes, and one minute into 60 seconds, use of degrees-minutes-seconds is also called DMS notation. These subdivisions, also called the arcminute and arcsecond, are represented by a single and double prime. For example,40. 1875° = 40° 11′ 15″, or, using quotation mark characters, additional precision can be provided using decimals for the arcseconds component. The older system of thirds, fourths, etc. which continues the sexagesimal unit subdivision, was used by al-Kashi and other ancient astronomers, but is rarely used today
13.
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
14.
Longitude of the ascending node
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The longitude of the ascending node is one of the orbital elements used to specify the orbit of an object in space. It is the angle from a direction, called the origin of longitude, to the direction of the ascending node. The ascending node is the point where the orbit of the passes through the plane of reference. Commonly used reference planes and origins of longitude include, For a geocentric orbit, Earths equatorial plane as the plane. In this case, the longitude is called the right ascension of the ascending node. The angle is measured eastwards from the First Point of Aries to the node, for a heliocentric orbit, the ecliptic as the reference plane, and the First Point of Aries as the origin of longitude. The angle is measured counterclockwise from the First Point of Aries to the node, the angle is measured eastwards from north to the node. pp.40,72,137, chap. In the case of a star known only from visual observations, it is not possible to tell which node is ascending. In this case the orbital parameter which is recorded is the longitude of the node, Ω, here, n=<nx, ny, nz> is a vector pointing towards the ascending node. The reference plane is assumed to be the xy-plane, and the origin of longitude is taken to be the positive x-axis, K is the unit vector, which is the normal vector to the xy reference plane. For non-inclined orbits, Ω is undefined, for computation it is then, by convention, set equal to zero, that is, the ascending node is placed in the reference direction, which is equivalent to letting n point towards the positive x-axis. Kepler orbits Equinox Orbital node perturbation of the plane can cause revolution of the ascending node
15.
Argument of periapsis
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The argument of periapsis, symbolized as ω, is one of the orbital elements of an orbiting body. Parametrically, ω is the angle from the ascending node to its periapsis. For specific types of orbits, words such as perihelion, perigee, periastron, an argument of periapsis of 0° means that the orbiting body will be at its closest approach to the central body at the same moment that it crosses the plane of reference from South to North. An argument of periapsis of 90° means that the body will reach periapsis at its northmost distance from the plane of reference. Adding the argument of periapsis to the longitude of the ascending node gives the longitude of the periapsis, however, especially in discussions of binary stars and exoplanets, the terms longitude of periapsis or longitude of periastron are often used synonymously with argument of periapsis. In the case of equatorial orbits, the argument is strictly undefined, where, ex and ey are the x- and y-components of the eccentricity vector e. In the case of circular orbits it is assumed that the periapsis is placed at the ascending node. Kepler orbit Orbital mechanics Orbital node
16.
Minimum orbit intersection distance
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Minimum orbit intersection distance is a measure used in astronomy to assess potential close approaches and collision risks between astronomical objects. It is defined as the distance between the closest points of the orbits of two bodies. Of greatest interest is the risk of a collision with Earth, Earth MOID is often listed on comet and asteroid databases such as the JPL Small-Body Database. MOID values are defined with respect to other bodies as well, Jupiter MOID, Venus MOID. An object is classified as a hazardous object – that is, posing a possible risk to Earth – if, among other conditions. A low MOID does not mean that a collision is inevitable as the planets frequently perturb the orbit of small bodies. It is also necessary that the two bodies reach that point in their orbits at the time before the smaller body is perturbed into a different orbit with a different MOID value. Two Objects gravitationally locked in orbital resonance may never approach one another, numerical integrations become increasingly divergent as trajectories are projected further forward in time, especially beyond times where the smaller body is repeatedly perturbed by other planets. MOID has the convenience that it is obtained directly from the elements of the body. The only object that has ever been rated at 4 on the Torino Scale and this is not the smallest Earth MOID in the catalogues, many bodies with a small Earth MOID are not classed as PHOs because the objects are less than roughly 140 meters in diameter. Earth MOID values are more practical for asteroids less than 140 meters in diameter as those asteroids are very dim. It is even smaller at the more precise JPL Small Body Database
17.
Albedo
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Albedo is a measure for reflectance or optical brightness. It is dimensionless and measured on a scale from zero to one, surface albedo is defined as the ratio of radiation reflected to the radiation incident on a surface. The proportion reflected is not only determined by properties of the surface itself and these factors vary with atmospheric composition, geographic location and time. While bi-hemispherical reflectance is calculated for an angle of incidence. The temporal resolution may range from seconds to daily, seasonal or annual averages, unless given for a specific wavelength, albedo refers to the entire spectrum of solar radiation. Due to measurement constraints, it is given for the spectrum in which most solar energy reaches the surface. This spectrum includes visible light, which explains why surfaces with a low albedo appear dark, albedo is an important concept in climatology, astronomy, and environmental management. The term albedo was introduced into optics by Johann Heinrich Lambert in his 1760 work Photometria, any albedo in visible light falls within a range of about 0.9 for fresh snow to about 0.04 for charcoal, one of the darkest substances. Deeply shadowed cavities can achieve an effective albedo approaching the zero of a black body, when seen from a distance, the ocean surface has a low albedo, as do most forests, whereas desert areas have some of the highest albedos among landforms. Most land areas are in a range of 0.1 to 0.4. The average albedo of Earth is about 0.3 and this is far higher than for the ocean primarily because of the contribution of clouds. Earths surface albedo is regularly estimated via Earth observation satellite sensors such as NASAs MODIS instruments on board the Terra, thereby, the BRDF allows to translate observations of reflectance into albedo. Earths average surface temperature due to its albedo and the effect is currently about 15 °C. If Earth were frozen entirely, the temperature of the planet would drop below −40 °C. If only the land masses became covered by glaciers, the mean temperature of the planet would drop to about 0 °C. In contrast, if the entire Earth was covered by water — a so-called aquaplanet — the average temperature on the planet would rise to almost 27 °C, hence, the actual albedo α can then be given as, α = α ¯ + D α ¯ ¯. Directional-hemispherical reflectance is sometimes referred to as black-sky albedo and bi-hemispherical reflectance as white-sky albedo and these terms are important because they allow the albedo to be calculated for any given illumination conditions from a knowledge of the intrinsic properties of the surface. The albedos of planets, satellites and asteroids can be used to infer much about their properties, the study of albedos, their dependence on wavelength, lighting angle, and variation in time comprises a major part of the astronomical field of photometry
18.
Hour
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An hour is a unit of time conventionally reckoned as 1⁄24 of a day and scientifically reckoned as 3, 599–3,601 seconds, depending on conditions. The seasonal, temporal, or unequal hour was established in the ancient Near East as 1⁄12 of the night or daytime, such hours varied by season, latitude, and weather. It was subsequently divided into 60 minutes, each of 60 seconds, the modern English word hour is a development of the Anglo-Norman houre and Middle English ure, first attested in the 13th century. It displaced the Old English tide and stound, the Anglo-Norman term was a borrowing of Old French ure, a variant of ore, which derived from Latin hōra and Greek hṓrā. Like Old English tīd and stund, hṓrā was originally a word for any span of time, including seasons. Its Proto-Indo-European root has been reconstructed as *yeh₁-, making hour distantly cognate with year, the time of day is typically expressed in English in terms of hours. Whole hours on a 12-hour clock are expressed using the contracted phrase oclock, Hours on a 24-hour clock are expressed as hundred or hundred hours. Fifteen and thirty minutes past the hour is expressed as a quarter past or after and half past, respectively, fifteen minutes before the hour may be expressed as a quarter to, of, till, or before the hour. Sumerian and Babylonian hours divided the day and night into 24 equal hours, the ancient Egyptians began dividing the night into wnwt at some time before the compilation of the Dynasty V Pyramid Texts in the 24th century BC. By 2150 BC, diagrams of stars inside Egyptian coffin lids—variously known as diagonal calendars or star clocks—attest that there were exactly 12 of these. The coffin diagrams show that the Egyptians took note of the risings of 36 stars or constellations. Each night, the rising of eleven of these decans were noted, the original decans used by the Egyptians would have fallen noticeably out of their proper places over a span of several centuries. By the time of Amenhotep III, the priests at Karnak were using water clocks to determine the hours and these were filled to the brim at sunset and the hour determined by comparing the water level against one of its twelve gauges, one for each month of the year. During the New Kingdom, another system of decans was used, the later division of the day into 12 hours was accomplished by sundials marked with ten equal divisions. The morning and evening periods when the failed to note time were observed as the first and last hours. The Egyptian hours were closely connected both with the priesthood of the gods and with their divine services, by the New Kingdom, each hour was conceived as a specific region of the sky or underworld through which Ras solar bark travelled. Protective deities were assigned to each and were used as the names of the hours, as the protectors and resurrectors of the sun, the goddesses of the night hours were considered to hold power over all lifespans and thus became part of Egyptian funerary rituals. The Egyptian for astronomer, used as a synonym for priest, was wnwty, the earliest forms of wnwt include one or three stars, with the later solar hours including the determinative hieroglyph for sun
19.
Day
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In common usage, it is either an interval equal to 24 hours or daytime, the consecutive period of time during which the Sun is above the horizon. The period of time during which the Earth completes one rotation with respect to the Sun is called a solar day, several definitions of this universal human concept are used according to context, need and convenience. In 1960, the second was redefined in terms of the motion of the Earth. The unit of measurement day, redefined in 1960 as 86400 SI seconds and symbolized d, is not an SI unit, but is accepted for use with SI. The word day may also refer to a day of the week or to a date, as in answer to the question. The life patterns of humans and many species are related to Earths solar day. In recent decades the average length of a day on Earth has been about 86400.002 seconds. A day, understood as the span of time it takes for the Earth to make one rotation with respect to the celestial background or a distant star, is called a stellar day. This period of rotation is about 4 minutes less than 24 hours, mainly due to tidal effects, the Earths rotational period is not constant, resulting in further minor variations for both solar days and stellar days. Other planets and moons have stellar and solar days of different lengths to Earths, besides the day of 24 hours, the word day is used for several different spans of time based on the rotation of the Earth around its axis. An important one is the day, defined as the time it takes for the Sun to return to its culmination point. Because the Earth orbits the Sun elliptically as the Earth spins on an inclined axis, on average over the year this day is equivalent to 24 hours. A day, in the sense of daytime that is distinguished from night-time, is defined as the period during which sunlight directly reaches the ground. The length of daytime averages slightly more than half of the 24-hour day, two effects make daytime on average longer than nights. The Sun is not a point, but has an apparent size of about 32 minutes of arc, additionally, the atmosphere refracts sunlight in such a way that some of it reaches the ground even when the Sun is below the horizon by about 34 minutes of arc. So the first light reaches the ground when the centre of the Sun is still below the horizon by about 50 minutes of arc, the difference in time depends on the angle at which the Sun rises and sets, but can amount to around seven minutes. Ancient custom has a new day start at either the rising or setting of the Sun on the local horizon, the exact moment of, and the interval between, two sunrises or sunsets depends on the geographical position, and the time of year. A more constant day can be defined by the Sun passing through the local meridian, the exact moment is dependent on the geographical longitude, and to a lesser extent on the time of the year
20.
C-type asteroid
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They are the most common variety, forming around 75% of known asteroids. They are distinguished by a low albedo because their composition includes a large amount of carbon, in addition to rocks. Asteroids of this class have very similar to those of carbonaceous chondrite meteorites. The latter are very close in composition to the Sun. C-type asteroids are extremely dark, with albedos typically in the 0.03 to 0.10 range, consequently, whereas a number of S-type asteroids can normally be viewed with binoculars at opposition, even the largest C-type asteroids require a small telescope. The potentially brightest C-type asteroid is 324 Bamberga, but that very high eccentricity means it rarely reaches its maximum magnitude. Their spectra contain moderately strong ultraviolet absorption at wavelengths below about 0.4 μm to 0.5 μm, while at longer wavelengths they are largely featureless but slightly reddish. The so-called water absorption feature around 3 μm, which can be an indication of content in minerals is also present
21.
Asteroid
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Asteroids are minor planets, especially those of the inner Solar System. The larger ones have also been called planetoids and these terms have historically been applied to any astronomical object orbiting the Sun that did not show the disc of a planet and was not observed to have the characteristics of an active comet. As minor planets in the outer Solar System were discovered and found to have volatile-based surfaces that resemble those of comets, in this article, the term asteroid refers to the minor planets of the inner Solar System including those co-orbital with Jupiter. There are millions of asteroids, many thought to be the remnants of planetesimals. The large majority of known asteroids orbit in the belt between the orbits of Mars and Jupiter, or are co-orbital with Jupiter. However, other orbital families exist with significant populations, including the near-Earth objects, individual asteroids are classified by their characteristic spectra, with the majority falling into three main groups, C-type, M-type, and S-type. These were named after and are identified with carbon-rich, metallic. The size of asteroids varies greatly, some reaching as much as 1000 km across, asteroids are differentiated from comets and meteoroids. In the case of comets, the difference is one of composition, while asteroids are composed of mineral and rock, comets are composed of dust. In addition, asteroids formed closer to the sun, preventing the development of the aforementioned cometary ice, the difference between asteroids and meteoroids is mainly one of size, meteoroids have a diameter of less than one meter, whereas asteroids have a diameter of greater than one meter. Finally, meteoroids can be composed of either cometary or asteroidal materials, only one asteroid,4 Vesta, which has a relatively reflective surface, is normally visible to the naked eye, and this only in very dark skies when it is favorably positioned. Rarely, small asteroids passing close to Earth may be visible to the eye for a short time. As of March 2016, the Minor Planet Center had data on more than 1.3 million objects in the inner and outer Solar System, the United Nations declared June 30 as International Asteroid Day to educate the public about asteroids. The date of International Asteroid Day commemorates the anniversary of the Tunguska asteroid impact over Siberia, the first asteroid to be discovered, Ceres, was found in 1801 by Giuseppe Piazzi, and was originally considered to be a new planet. In the early half of the nineteenth century, the terms asteroid. Asteroid discovery methods have improved over the past two centuries. This task required that hand-drawn sky charts be prepared for all stars in the band down to an agreed-upon limit of faintness. On subsequent nights, the sky would be charted again and any moving object would, hopefully, the expected motion of the missing planet was about 30 seconds of arc per hour, readily discernible by observers
22.
G-type asteroid
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G-type asteroids are a relatively uncommon type of carbonaceous asteroid that makes up approximately 5% of asteroids. The most notable asteroid in this class is 1 Ceres, generally similar to the C-type objects, but contain a strong ultraviolet absorption feature below 0.5 μm. An absorption feature around 0.7 μm may also be present, in the SMASS classification the G-type corresponds to the Cgh and Cg types, depending on the presence or absence of the absorption feature at 0.7 μm. The G-type, C-type and some types are sometimes collected together into a wider C-group of carbonaceous asteroids. Asteroid spectral types D. J. Tholen Asteroid taxonomic classifications in Asteroids III
23.
Space probe
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A space probe is a robotic spacecraft that does not orbit the Earth, but, instead, explores further into outer space. A space probe may approach the Moon, travel through space, flyby, orbit, or land on other planetary bodies. Approximately fifteen missions are currently operational, once a probe has left the vicinity of Earth, its trajectory will likely take it along an orbit around the Sun similar to the Earths orbit. To reach another planet, the simplest practical method is a Hohmann transfer orbit, more complex techniques, such as gravitational slingshots, can be more fuel-efficient, though they may require the probe to spend more time in transit. Some high Delta-V missions can only be performed, within the limits of modern propulsion, a technique using very little propulsion, but requiring a considerable amount of time, is to follow a trajectory on the Interplanetary Transport Network. First man-made object to land on the Moon, or any other extra terrestrial surface. First mission to photograph the far side of the Moon, launched in 1959, first robotic sample return probe from the Moon. It was sent to the Moon on November 10,1970, first successful in-place analysis of another planet. It may have also been the first space probe to impact the surface of another planet, the Venera 7 probe was the first spacecraft to successfully soft land on another planet and to transmit data from there back to Earth. Upon its arrival at Mars on November 13,1971, Mariner 9 became the first space probe to orbit around another planet. Although, the spacecraft failed shortly after landing, the Mars Exploration Rovers, Spirit and Opportunity surface and geology, and searched for clues to past water activity on Mars. They were each launched in 2003 and landed in 2004, communication with Spirit stopped on sol 2210. JPL continued to attempt to regain contact until May 24,2011, Opportunity arrived at Endeavour crater on 9 August 2011, at a landmark called Spirit Point named after its rover twin, after traversing 13 miles from Victoria crater, over a three-year period. As of January 26,2016, Opportunity has lasted for more than twelve years on Mars — although the rovers were intended to last only three months. The first dedicated missions to a comet, in this case and they dropped landers and balloons at Venus before their rendezvous with Halleys Comet. This Japanese probe was the first non-US, non-Soviet interplanetary probe, a second Japanese probe, it made ultraviolet wavelength observations of the comet. The first space probe to penetrate a comets coma and take images of its nucleus. First solar wind sample return probe from sun-earth L1, first sample return probe from a comet tail
24.
Sample-return mission
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A sample-return mission is a spacecraft mission with the goal of collecting and returning with tangible samples from an extraterrestrial location to Earth for analysis. Sample-return missions may bring back merely atoms and molecules or a deposit of complex compounds such as loose material, up to the present, humanity has collected samples of six identified Solar System bodies, as well as samples of the solar wind. Samples of Moon rock from Earths Moon were collected both from meteorites and through unmanned and manned sample-return missions, the comet Wild 2 and the asteroid 25143 Itokawa were visited by unmanned spacecraft, which returned samples to Earth. Samples available on Earth can be analyzed in laboratories, so we can further our understanding and knowledge as part of the discovery, Samples analyzed on Earth can be matched against findings of remote sensing, for more insight into the processes that formed the Solar System. These meteorites could then be identified as material ejected from the impact crater Rheasilvia on Vesta. This allowed deducing the composition of crust, mantle and core of Vesta, similarly some differences in composition of asteroids can be discerned by imaging alone. Several sample-return missions to asteroids and comets are currently in the works, more samples from asteroids and comets will help determine whether life formed in space and was carried to Earth in the form of meteorites. Another question under investigation is whether extraterrestrial life formed on other Solar System bodies like Mars or on the moons of the gas giants, jupiters moon Europa is another important focus in the search for life in the Solar System. However, due to the distance and other constraints, Europa might not be the target of a mission in the foreseeable future. A sample return from Mars or Europa or other location with possibility to have life is a category V mission under COSPAR, No sample has yet been returned with alien life in it, so we have no past experience to guide us. In the most interesting case, a sample returned from these locations might contain such life and it is not known what effects are likely on humans or the environment of the Earth. It might have no effect, due to the dominance of present life on Earth, the contrary, worst-case argument is that we would not be adapted to be able to resist it, and that alien life would not be adapted to have no harmful effects. Also some diseases can leap directly to an animal host, such as Legionnaires disease, jumped straight to humans, the manned US Apollo 11 mission in July 1969 achieved the first successful sample return from another Solar System body. It returned approximately 22 kilograms of Lunar surface material and this was followed by 34 kilograms of material from Apollo 12 and further 326 kilograms material from four more missions from the manned Apollo program. Perhaps one of the most significant advances in sample-return missions occurred in 1970 when the robotic Soviet mission known as Luna 16, likewise, Luna 20 returned 55 grams in 1974, and Luna 24 returned 170 grams in 1976. Although they recovered far less than the Apollo missions, they did this fully automatically, beside these three successes, other attempts under Luna programme failed. The first two missions intended to outstrip Apollo 11 and were shortly before them in June and July 1969, Luna E-8-5 No.402 failed at start. In 1970, the Soviet Union planned for a 1975 first Martian sample-return mission in the Mars 5NM project and this Mars 5M mission was planned for 1979, but got canceled in 1977 due to technical problems and complexity, all hardware was ordered destroyed
25.
Japanese folklore
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Japanese folklore encompasses the folk traditions of Japan and the Japanese people. In Japanese, the term minkan denshō is used to describe folklore, folklorists also employ the term minzoku shiryō or folklore material to refer to objects and arts they study. Men dressed as namahage, wearing masks and traditional straw capes make rounds of homes. These ogre-men masquerade as kami looking to instill fear in the children who are lazily idling around the fire and this is a particularly colorful example of folk practice still kept alive. A parallel custom is the secretive Akamata-Kuromata ritual of the Yaeyama Islands, many, though increasingly fewer households maintain a kamidana or a small Shinto altar shelf. The Shinto version of the god is the Kamado kami, and the syncretic Buddhist version is the Kōjin. Japanese popular cults or kō are sometimes devoted to particular deities and buddhas, but many cults centered around paying respects to sacred sites such as the Ise Shrine or Mount Fuji. Pilgrimage to these meccas declined after the Edo Period, but recently, the Shikoku Pilgrimage of the eighty-eight temple sites has become fashionable. Popular media and cottage industries now extoll a number of shrines, there is a long list of practices performed to ward evil or expel evil, e. g. sounding the drums. In some areas it is common to place a small mound of salt outside the house, a stock routine in period or even contemporary drama involves a master of the house telling his wife to scatter salt after an undesirable visitor has just left. Contrarily, lighting sparks with flint just as a someone is leaving the house was considered lucky. No one now engages in the silent vigil required by the Kōshin cult, there are certain vestiges of geomancy introduced into Japan from China through Onmyōdō. There is also a Japanese version of Feng Shui known as kasō or literally house physiognomy, closely connected is the Yin-yang path or Onmyōdō, and its concepts such as katatagae also known as kataimi, which was widely practiced by nobles in the Heian Era. A widely known taboo advises against sleeping with your head faced north, as in most developed nations, it is increasingly difficult to find living storytellers of oral tradition. But there is a wealth of folktales collected through the ages, the name mukashi-banashi has been applied to the common folktale, since they typically open with the formula Mukashi. They also close with some set phrase like dotto harai and these tales had been told in their local dialects, which may be difficult to understand to outsiders, both because of intonation and pronunciation differences, conjugations, and vocabulary. Many folktales collected from the field are actually translations into standard Japanese, the versions retold by childrens story author Sazanami Iwaya had a strong hand in establishing the forms usually known today. Two creatures are known for their abilities to transform into humans or other beings and objects
26.
Diameter
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In geometry, a diameter of a circle is any straight line segment that passes through the center of the circle and whose endpoints lie on the circle. It can also be defined as the longest chord of the circle, both definitions are also valid for the diameter of a sphere. In more modern usage, the length of a diameter is called the diameter. In this sense one speaks of the rather than a diameter, because all diameters of a circle or sphere have the same length. Both quantities can be calculated efficiently using rotating calipers, for a curve of constant width such as the Reuleaux triangle, the width and diameter are the same because all such pairs of parallel tangent lines have the same distance. For an ellipse, the terminology is different. A diameter of an ellipse is any chord passing through the midpoint of the ellipse, for example, conjugate diameters have the property that a tangent line to the ellipse at the endpoint of one of them is parallel to the other one. The longest diameter is called the major axis, the word diameter is derived from Greek διάμετρος, diameter of a circle, from διά, across, through and μέτρον, measure. It is often abbreviated DIA, dia, d, or ⌀, the definitions given above are only valid for circles, spheres and convex shapes. However, they are cases of a more general definition that is valid for any kind of n-dimensional convex or non-convex object. The diameter of a subset of a space is the least upper bound of the set of all distances between pairs of points in the subset. So, if A is the subset, the diameter is sup, if the distance function d is viewed here as having codomain R, this implies that the diameter of the empty set equals −∞. Some authors prefer to treat the empty set as a case, assigning it a diameter equal to 0. For any solid object or set of scattered points in n-dimensional Euclidean space, in medical parlance concerning a lesion or in geology concerning a rock, the diameter of an object is the supremum of the set of all distances between pairs of points in the object. In differential geometry, the diameter is an important global Riemannian invariant, the symbol or variable for diameter, ⌀, is similar in size and design to ø, the Latin small letter o with stroke. In Unicode it is defined as U+2300 ⌀ Diameter sign, on an Apple Macintosh, the diameter symbol can be entered via the character palette, where it can be found in the Technical Symbols category. The character will not display correctly, however, since many fonts do not include it. In many situations the letter ø is a substitute, which in Unicode is U+00F8 ø
27.
Planetary Resources
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Planetary Resources, Inc. formerly known as Arkyd Astronautics, is an American company that was formed in November 2010, and reorganized and renamed in 2012. Their stated goal is to expand Earths natural resource base by developing and deploying the technologies for asteroid mining, although the long-term goal of the company is to mine asteroids, its initial plans call for developing a market for small cost-reduced space telescopes for both Earth observation and astronomy. These spacecraft would employ a system for ground communications, reducing payload bulk. The deployment of such orbital telescopes is envisioned as the first step forward in the companys asteroid mining ambitions, the same telescope satellite capabilities that Planetary Resources hopes to sell to customers can be used to survey and intensively examine near-Earth asteroids. The Reflight descriptor was used because Planetarys first satellite, Arkyd 3, was destroyed on October 28,2014 after an Antares resupply rocket exploded seconds after launch. Arkyd Astronautics was founded in November 2010, with Peter Diamandis as co-chairman and director, according to co-founder Eric Andersen, the name Arkyd Astronautics was deliberately ambiguous, to help keep the companys asteroid-mining agenda secret. The company gained attention in April 2012 with the announcement of a press conference. The initial press release provided limited information, as of April 20,2012, included in the list were a number of people notable for their entrepreneurship and interest in space, exploration, and research. Some also had involvement in space research. It was speculated that Planetary Resources was looking for ways to extract raw materials from non-Earth sources, Arkyd Astronautics became a wholly owned subsidiary of Planetary Resources. By January 2013, Planetary Resources had completed a ground test prototype of the Arkyd-100, in May 2013, Planetary Resources announced the launch of Kickstarter funding for the ARKYD-100. Their goal was surpassed on 19 June 2013, in April 2013, the company announced that they planned on launching a CubeSat called Arkyd-3 in early 2014, as a testbed manifestation for the Arkyd-100 spacecraft. The purpose of the flight is to test technologies for the first Arkyd-100 spacecraft, in the event, the first A3 was launched in fall 2014 but was destroyed in a launch accident, a second A3 spacecraft—designated A3R—was launched in April 2015 and deployed into orbit in July 2015. By mid-2016, the company had grown to 60 employees, in November 2016, Luxembourg invested $25 million euros in the company in the form of capital and research and development grants. The company announced the investment would be used for the launch of its first asteroid prospecting mission by 2020, Luxembourg had recently adopted draft legislation giving private operators rights to materials mined in space. Planetary Resources aims to develop a robotic asteroid mining industry, to achieve this, the company is operating on the basis of a long-term strategic plan. The first stage will be a survey and analysis, using purpose-built satellites in Earth orbit, several small space telescopes, with various sensing capabilities, are to be launched for this purpose. The company website asserts that their space telescopes will be available for hire
28.
Jet Propulsion Laboratory
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The Jet Propulsion Laboratory is a federally funded research and development center and NASA field center in La Cañada Flintridge, California and Pasadena, California, United States. The JPL is managed by the nearby California Institute of Technology for NASA, the laboratorys primary function is the construction and operation of planetary robotic spacecraft, though it also conducts Earth-orbit and astronomy missions. It is also responsible for operating NASAs Deep Space Network and they are also responsible for managing the JPL Small-Body Database, and provides physical data and lists of publications for all known small Solar System bodies. The JPLs Space Flight Operations Facility and Twenty-Five-Foot Space Simulator are designated National Historic Landmarks, JPL traces its beginnings to 1936 in the Guggenheim Aeronautical Laboratory at the California Institute of Technology when the first set of rocket experiments were carried out in the Arroyo Seco. Malinas thesis advisor was engineer/aerodynamicist Theodore von Kármán, who arranged for U. S. Army financial support for this GALCIT Rocket Project in 1939. In 1941, Malina, Parsons, Forman, Martin Summerfield, in 1943, von Kármán, Malina, Parsons, and Forman established the Aerojet Corporation to manufacture JATO motors. The project took on the name Jet Propulsion Laboratory in November 1943, during JPLs Army years, the laboratory developed two deployed weapon systems, the MGM-5 Corporal and MGM-29 Sergeant intermediate range ballistic missiles. These missiles were the first US ballistic missiles developed at JPL and it also developed a number of other weapons system prototypes, such as the Loki anti-aircraft missile system, and the forerunner of the Aerobee sounding rocket. At various times, it carried out testing at the White Sands Proving Ground, Edwards Air Force Base. A lunar lander was developed in 1938-39 which influenced design of the Apollo Lunar Module in the 1960s. The team lost that proposal to Project Vanguard, and instead embarked on a project to demonstrate ablative re-entry technology using a Jupiter-C rocket. They carried out three successful flights in 1956 and 1957. Using a spare Juno I, the two organizations then launched the United States first satellite, Explorer 1, on February 1,1958, JPL was transferred to NASA in December 1958, becoming the agencys primary planetary spacecraft center. JPL engineers designed and operated Ranger and Surveyor missions to the Moon that prepared the way for Apollo, JPL also led the way in interplanetary exploration with the Mariner missions to Venus, Mars, and Mercury. In 1998, JPL opened the Near-Earth Object Program Office for NASA, as of 2013, it has found 95% of asteroids that are a kilometer or more in diameter that cross Earths orbit. JPL was early to employ women mathematicians, in the 1940s and 1950s, using mechanical calculators, women in an all-female computations group performed trajectory calculations. In 1961, JPL hired Dana Ulery as their first woman engineer to work alongside male engineers as part of the Ranger and Mariner mission tracking teams, when founded, JPLs site was a rocky flood-plain just outside the city limits of Pasadena. Almost all of the 177 acres of the U. S, the city of La Cañada Flintridge, California was incorporated in 1976, well after JPL attained international recognition with a Pasadena address
. Bibcode:2009A&A...503L..17C. doi:10.1051/0004-6361/200912374.
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