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Mars Mars Mars is the fourth planet from the Sun Sun and the secondsmallest planet in the Solar System Solar System after Mercury. In English, Mars Mars carries a name of the Roman god of war, and is often referred to as the "Red Planet"[14][15] because the reddish iron oxide prevalent on its surface gives it a reddish appearance that is distinctive among the astronomical bodies visible to the naked eye.[16] Mars Mars is a terrestrial planet with a thin atmosphere, having surface features reminiscent both of the impact craters of the Moon Moon and the valleys, deserts, and polar ice caps of Earth. The rotational period and seasonal cycles of Mars Mars are likewise similar to those of Earth, as is the tilt that produces the seasons [...More...] 


Geographical Pole A geographical pole is either of the two points on a rotating body (planet, dwarf planet, natural satellite, sphere...etc) where its axis of rotation intersects its surface.[1] As with Earth's North and South Poles, they are usually called that body's "north pole" and "south pole", one lying 90 degrees in one direction from the body's equator and the other lying 90 degrees in the opposite direction from the equator. Every planet has geographical poles.[2] If, like the Earth, a body generates a magnetic field, it will also possess magnetic poles.[3] Perturbations in a body's rotation mean that geographical poles wander slightly on its surface [...More...] 


Orbital Speed In gravitationally bound systems, the orbital speed of an astronomical body or object (e.g. planet, moon, artificial satellite, spacecraft, or star) is the speed at which it orbits around either the barycenter or, if the object is much less massive than the largest body in the system, its speed relative to that largest body. The speed in this latter case may be relative to the surface of the larger body or relative to its center of mass. The term can be used to refer to either the mean orbital speed, i.e. the average speed over an entire orbit, or its instantaneous speed at a particular point in its orbit. Maximum (instantaneous) orbital speed occurs at periapsis (perigee, perhelion, etc.), while minimum speed for objects in closed orbits occurs at apoapsis (aphelion, apogee, etc.) [...More...] 


Declination In astronomy, declination (abbreviated dec; symbol δ) is one of the two angles that locate a point on the celestial sphere in the equatorial coordinate system, the other being hour angle. Declination's angle is measured north or south of the celestial equator, along the hour circle passing through the point in question.[1] Right ascension Right ascension and declination as seen on the inside of the celestial sphere. The primary direction of the system is the vernal equinox, the ascending node of the ecliptic (red) on the celestial equator (blue). Declination Declination is measured northward or southward from the celestial equator, along the hour circle passing through the point in question.The root of the word declination (Latin, declinatio) means "a bending away" or "a bending down" [...More...] 


Gforce The gforce (with g from gravitational) is a measurement of the type of acceleration that causes a perception of weight. Despite the name, it is incorrect to consider gforce a fundamental force, as "gforce" (lowercase character) is a type of acceleration that can be measured with an accelerometer. Since gforce accelerations indirectly produce weight, any gforce can be described as a "weight per unit mass" (see the synonym specific weight). When the gforce acceleration is produced by the surface of one object being pushed by the surface of another object, the reaction force to this push produces an equal and opposite weight for every unit of an object's mass. The types of forces involved are transmitted through objects by interior mechanical stresses [...More...] 


Albedo Albedo Albedo (/ælˈbiːdoʊ/) (Latin: albedo, meaning "whiteness") is the measure of the diffuse reflection of solar radiation out of the total solar radiation received by an astronomical body (e.g. a planet like Earth). It is dimensionless and measured on a scale from 0 (corresponding to a black body that absorbs all incident radiation) to 1 (corresponding to a body that reflects all incident radiation). Surface albedo is defined as the ratio of irradiance reflected to the irradiance received by a surface. The proportion reflected is not only determined by properties of the surface itself, but also by the spectral and angular distribution of solar radiation reaching the Earth's surface.[1] These factors vary with atmospheric composition, geographic location and time (see position of the Sun) [...More...] 


Density The density, or more precisely, the volumetric mass density, of a substance is its mass per unit volume. The symbol most often used for density is ρ (the lower case Greek letter rho), although the Latin letter D can also be used. Mathematically, density is defined as mass divided by volume:[1] ρ = m V displaystyle rho = frac m V where ρ is the density, m is the mass, and V is the volume. In some cases (for instance, in the United States oil and gas industry), density is loosely defined as its weight per unit volume,[2] although this is scientifically inaccurate – this quantity is more specifically called specific weight. For a pure substance the density has the same numerical value as its mass concentration. Different materials usually have different densities, and density may be relevant to buoyancy, purity and packaging [...More...] 


Volume Volume Volume is the quantity of threedimensional space enclosed by a closed surface, for example, the space that a substance (solid, liquid, gas, or plasma) or shape occupies or contains.[1] Volume Volume is often quantified numerically using the SI derived unit, the cubic metre. The volume of a container is generally understood to be the capacity of the container; i. e., the amount of fluid (gas or liquid) that the container could hold, rather than the amount of space the container itself displaces. Three dimensional mathematical shapes are also assigned volumes. Volumes of some simple shapes, such as regular, straightedged, and circular shapes can be easily calculated using arithmetic formulas [...More...] 


Flattening Flattening Flattening is a measure of the compression of a circle or sphere along a diameter to form an ellipse or an ellipsoid of revolution (spheroid) respectively. Other terms used are ellipticity, or oblateness. The usual notation for flattening is f and its definition in terms of the semiaxes of the resulting ellipse or ellipsoid is f l a t t e n i n g = f = a − b a . displaystyle mathrm flattening =f= frac ab a . The compression factor is b/a in each case. For the ellipse, this factor is also the aspect ratio of the ellipse. There are two other variants of flattening (see below) and when it is necessary to avoid confusion the above flattening is called the first flattening [...More...] 


Temperature Temperature Temperature is a physical quantity expressing hot and cold. Temperature Temperature is measured with a thermometer, historically calibrated in various temperature scales and units of measurement. The most commonly used scales are the Celsius Celsius scale, denoted in °C (informally, degrees centigrade), the Fahrenheit scale Fahrenheit scale (°F), and the Kelvin Kelvin scale. The kelvin (K) is the unit of temperature in the International System of Units (SI), in which temperature is one of the seven fundamental base quantities. The coldest theoretical temperature is absolute zero, at which the thermal motion of all fundamental particles in matter reaches a minimum. Although classically described as motionless, particles still possess a finite zeropoint energy in the quantum mechanical description [...More...] 


Argument Of Periapsis The argument of periapsis (also called argument of perifocus or argument of pericenter), symbolized as ω, is one of the orbital elements of an orbiting body. Parametrically, ω is the angle from the body's ascending node to its periapsis, measured in the direction of motion. For specific types of orbits, words such as perihelion (for heliocentric orbits), perigee (for geocentric orbits), periastron (for orbits around stars), and so on may replace the word periapsis. (See apsis for more information.) 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 orbiting 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 [...More...] 


Longitude Of The Ascending Node The longitude of the ascending node (☊ or Ω) is one of the orbital elements used to specify the orbit of an object in space. It is the angle from a reference direction, called the origin of longitude, to the direction of the ascending node, measured in a reference plane.[1] The ascending node is the point where the orbit of the object passes through the plane of reference, as seen in the adjacent image. Commonly used reference planes and origins of longitude include:For a geocentric orbit, Earth's equatorial plane as the reference plane, and the First Point of Aries First Point of Aries as the origin of longitude. In this case, the longitude is also called the right ascension of the ascending node, or RAAN [...More...] 


Equator An equator is the intersection of the surface of a rotating sphere (such as a planet) with the plane perpendicular to the axis of rotation and midway between its poles. On Earth, the Equator Equator is an imaginary line on the surface, equidistant from the North and South Poles, dividing the Earth Earth into Northern and Southern Hemispheres [...More...] 


Kelvin The Kelvin Kelvin scale is an absolute thermodynamic temperature scale using as its null point absolute zero, the temperature at which all thermal motion ceases in the classical description of thermodynamics. The kelvin (symbol: K) is the base unit of temperature in the International System of Units International System of Units (SI). The kelvin is defined as the fraction 1⁄273.16 of the thermodynamic temperature of the triple point of water (exactly 0.01 °C or 32.018 °F).[1] In other words, it is defined such that the triple point of water is exactly 273.16 K. The Kelvin Kelvin scale is named after the Belfastborn, Glasgow University engineer and physicist William Thomson, 1st Baron Kelvin (1824–1907), who wrote of the need for an "absolute thermometric scale". Unlike the degree Fahrenheit Fahrenheit and degree Celsius, the kelvin is not referred to or typeset as a degree [...More...] 


Celsius The Celsius Celsius scale, previously known as the centigrade scale,[1][2] is a temperature scale used by the International System of Units International System of Units (SI). As an SI derived unit, it is used by all countries in the world, except the United States, Myanmar, and Liberia. It is named after the Swedish astronomer Anders Celsius Anders Celsius (1701–1744), who developed a similar temperature scale. The degree Celsius Celsius (symbol: °C) can refer to a specific temperature on the Celsius Celsius scale as well as a unit to indicate a temperature interval, a difference between two temperatures or an uncertainty [...More...] 


Right Ascension Right ascension Right ascension (abbreviated RA; symbol α) is the angular distance measured eastward along the celestial equator from the Sun Sun at the March equinox to the hour circle of the point above the earth in question.[1] When paired with declination, these astronomical coordinates specify the direction of a point on the celestial sphere (traditionally called in English the skies or the sky) in the equatorial coordinate system. Right ascension Right ascension and declination as seen on the inside of the celestial sphere [...More...] 
