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| {{Redirect|Edge of space|the high-altitude region of Earth's atmosphere|near space|the boundary of the universe|observable universe}}
| | Jerrie Swoboda is what somebody can call me I totally dig regarding name. What me and my family will always love is acting but I can't make it my profession really. The job I've been occupying for years is a real people manager. Guam is even I've always been having. You can sometimes find my website here: http://circuspartypanama.com<br><br>Here is my homepage [http://circuspartypanama.com clash of clans cheats android] |
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| [[Image:Atmosphere layers-en.svg|thumb|right|180px|Layers of Atmosphere.<ref>http://www.srh.noaa.gov/srh/jetstream/atmos/layers.htm</ref> ''(not to scale)'']]
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| The '''Kármán line''', or '''Karman line''', lies at an [[altitude]] of {{convert|100|km|mi}} above the [[Earth]]'s [[sea level]], and commonly represents the boundary between the [[Earth's atmosphere]] and [[outer space]].<ref>{{cite web|url=http://www.fai.org/icare-records/100km-altitude-boundary-for-astronautics|title=The 100 km Boundary for Astronautics|publisher=[[Fédération Aéronautique Internationale]] Press Release|date=2004-06-24|format=DOC|accessdate=2006-10-30}}</ref> This definition is accepted by the [[Fédération Aéronautique Internationale]] (FAI), which is an international standard setting and record-keeping body for [[aeronautics]] and [[astronautics]].
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| The line is named after [[Theodore von Kármán]], (1881–1963) a [[Hungarian people|Hungarian]]-[[United States|American]] [[engineer]] and [[physicist]]. He was active primarily in [[aeronautics]] and [[astronautics]]. He was the first to calculate that around this altitude, the [[Earth's atmosphere|atmosphere]] becomes too thin to support aeronautical flight, because a vehicle at this altitude would have to travel faster than [[orbital speed|orbital velocity]] to derive sufficient [[aerodynamic lift]] to support itself (neglecting centrifugal force).<ref>{{cite book
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| | first=Beth Laura | last=O'Leary | year=2009
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| | title=Handbook of space engineering, archaeology, and heritage
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| | series=Advances in engineering | pages=84
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| | editors=Ann Garrison Darrin
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| | publisher=CRC Press | isbn=1-4200-8431-3
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| | url=http://books.google.com/books?id=dTwIDun4MroC&pg=PA84 }}</ref> There is an abrupt increase in [[atmospheric temperature]] and interaction with solar radiation just below the line, which places the line within the greater [[thermosphere]].
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| ==Definition==
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| An atmosphere does not abruptly end at any given height, but becomes progressively thinner with altitude. Also, depending on how the various layers that make up the space around the [[Earth]] are defined (and depending on whether these layers are considered part of the actual atmosphere), the definition of the edge of space could vary considerably: If one were to consider the [[thermosphere]] and [[exosphere]] part of the atmosphere and not of space, one might have to extend the boundary to space to at least {{convert|10,000|km|mi|abbr=on}} above sea level. The Kármán line thus is an arbitrary definition based on the following considerations:
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| An aircraft only stays in the sky if it constantly travels forward relative to the air (airspeed is not dependent on speed relative to ground), so that the wings can generate lift. The thinner the air, the faster the plane must go to generate enough lift to stay up.
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| If the [[lift coefficient]] for a wing at a specified [[angle of attack]] is known (or estimated using a method such as thin-airfoil theory), then the lift produced for specific flow conditions can be determined using the following equation{{Why|date=January 2014}}
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| :<math>
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| L = \tfrac12\rho v^2 A C_L
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| </math>
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| where
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| :L is [[lift force]]
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| :ρ is [[air density]]
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| :v is [[True airspeed|speed relative to the air]]
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| :A is [[planform area|wing area]],
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| :C<sub>L</sub> is the [[lift coefficient]] at the desired angle of attack, [[Mach number]], and [[Reynolds number]].
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| Lift (L) generated is directly proportional to the air density (ρ). All other factors remaining unchanged, true airspeed (v) must increase to compensate for less air density (ρ) at higher altitudes.
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| An [[orbit]]ing spacecraft only stays in the sky if the centrifugal component of its movement around the Earth is enough to balance the downward pull of [[gravity]]. If it goes slower, the pull of gravity gradually makes its altitude decrease. The required speed is called ''[[orbital speed|orbital velocity]],'' and it varies with the height of the orbit. For the [[International Space Station]], or a space shuttle in [[low Earth orbit]], the orbital velocity is about 27,000 km per hour (17,000 miles per hour).
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| For an airplane flying higher and higher, the increasingly thin air provides less and less [[lift (force)|lift]], requiring increasingly higher speed to create enough lift to hold the airplane up. It eventually reaches an altitude where it must fly so fast to generate lift that it reaches orbital velocity. The Kármán line is the altitude where the speed necessary to aerodynamically support the airplane's full weight equals orbital velocity (assuming wing loading of a typical airplane). In practice, supporting full weight wouldn't be necessary to maintain altitude because the curvature of the Earth adds centrifugal lift as the airplane reaches orbital speed. However, the Karman line definition ignores this effect because orbital velocity is implicitly sufficient to maintain any altitude regardless of atmospheric density. The Karman line is therefore the highest altitude at which orbital speed provides sufficient aerodynamic lift to fly in a straight line that doesn't follow the curvature of the Earth's surface.
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| When studying aeronautics and astronautics in the 1950s, Kármán calculated that above an altitude of roughly {{convert|100|km|mi|abbr =on}}, a vehicle would have to fly faster than orbital velocity to derive sufficient aerodynamic lift from the atmosphere to support itself.{{Citation needed|date=October 2011}} At this altitude, the air density is about 1/2200000 the density on the surface.<ref name=squire2000>{{citation
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| | first=Tom | last=Squire | date=September 27, 2000
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| | title=U.S. Standard Atmosphere, 1976 | publisher=NASA
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| | work=Thermal Protection Systems Expert and Material Properties Database
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| | url=http://tpsx.arc.nasa.gov/cgi-perl/alt.pl | accessdate=2011-10-23 }}</ref> At the Karman line, the air density ρ is such that
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| :<math>
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| L = \tfrac12\rho v_0^2 A C_L = mg
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| </math>
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|
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| where
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| :v<sub>0</sub> is orbital velocity
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| :m is mass of the aircraft
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| :g is acceleration due to gravity.
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| Although the calculated altitude was not exactly 100 km, Kármán proposed that 100 km be the designated boundary to space, because the round number is more memorable, and the calculated altitude varies minutely as certain parameters are varied. An international committee recommended the 100 km line to the FAI, and upon adoption, it became widely accepted as the boundary to space for many purposes.<ref>{{Cite web|title=Schneider walks the Walk [A word about the definition of space]|date=2005-10-21|url=http://www.nasa.gov/centers/dryden/news/X-Press/stories/2005/102105_Schneider.html|publisher=''[[NASA]]''|accessdate=2008-04-29}}</ref> However, there is still no international legal definition of the demarcation between a country's air space and outer space.<ref>[http://books.google.com/books?id=NR7mFXCB-wgC&pg=PA239&lpg=PA239&dq=legal+boundary+of+space&source=web&ots=Q56qiINocX&sig=bP5Ye5YBYytJpikkfp-lUznLJUk&hl=en ''International Law: A Dictionary''], by Boleslaw Adam Boczek; Scarecrow Press, 2005; page 239: "The issue whether it is possible or useful to establish a legal boundary between airspace and outer space has been debated in the doctrine for quite a long time. . . . no agreement exists on a fixed airspace - outer space boundary . . ."</ref>
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| Another hurdle to strictly defining the boundary to space is the dynamic nature of Earth's atmosphere. For example, at an altitude of {{convert|1,000|km|mi|abbr=on}}, the atmosphere's density can vary by a factor of five, depending on the time of day, time of year, [[Ionosphere#Solar flux|AP magnetic index]], and recent [[Ionosphere#Solar flux|solar flux]].{{Citation needed|date=December 2009}}
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| The FAI uses the Kármán line to define the boundary between aeronautics and astronautics:<ref>[http://www.fai.org/gliding/system/files/9.5.1+FAI+Nav+Glossary+draft.pdf PDF on the FAI website]</ref>
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| {{quotation|
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| *[[Aeronautics]] — For FAI purposes, aerial activity, including all air sports, within 100 kilometres of Earth's surface.''
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| *[[Astronautics]] — For FAI purposes, activity more than 100 kilometres above Earth's surface.}}
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| ==Interpretations of the definition==
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| Some people (including the FAI{{citation needed|date=October 2012}} in some of their publications) also use the expression "'''edge of space'''" to refer to a region below the conventional 100 km boundary to space, which is often meant to include substantially lower regions as well. Thus, certain [[balloon (aircraft)|balloon]] or [[airplane]] flights might be described as "reaching the edge of space". In such statements, "reaching the edge of space" merely refers to going higher than average aeronautical vehicles commonly would.<ref name=wings>{{cite web|url=http://www.nasa.gov/centers/dryden/news/X-Press/stories/2005/102105_Wings.html|title=A long-overdue tribute|publisher=NASA|date=2005-10-21|accessdate=2006-10-30}}</ref><ref>{{cite web|url=http://www.nasa.gov/worldbook/astronaut_worldbook.html|title=World Book @ NASA|publisher=NASA|accessdate=2006-10-18}}{{dead link|date=May 2012}}</ref>
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| ==Alternatives to the definition==
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| Although the [[United States]] does not officially define a ''boundary of space'', the U.S. definition of an [[astronaut]], which is still held today, is a person who has flown more than 50 miles (~80 km) [[above mean sea level]]. (This is approximately the line between the [[mesosphere]] and the [[thermosphere]].) This definition of an astronaut had been somewhat controversial, due to differing definitions between the [[United States military]] and [[NASA]].<ref name="wings" />
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| In 2005, three veteran NASA [[North American X-15|X-15]] pilots ([[John B. McKay]], [[Bill Dana (pilot)|Bill Dana]] and [[Joseph Albert Walker]]) were retroactively (two [[posthumous award|posthumous]]ly) awarded their [[Astronaut Badge|astronaut wings]], as they had flown between 90 and 108 km in the 1960s, but at the time had not been recognized as astronauts.<ref name="wings" />
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| [[International law]] defines the lower boundary of space as the lowest perigee attainable by an orbiting space vehicle, but does not specify an altitude. Due to atmospheric drag, the lowest altitude at which an object in a circular orbit can complete at least one full revolution without propulsion is approximately 150 km (93 mi), whereas an object can maintain an elliptical orbit with perigee as low as 129 km (80 mi) with propulsion.<ref name=Army>{{cite web|title=Space Environment and Orbital Mechanics|url=http://www.fas.org/spp/military/docops/army/ref_text/chap5im.htm|publisher=United States Army|accessdate=24 April 2012}}</ref>
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| [[Image:Top of Atmosphere.jpg|thumb|center|580px|Atmospheric gases scatter blue wavelengths of visible light more than other wavelengths, giving the Earth’s visible edge a blue halo. At higher and higher altitudes, the atmosphere becomes so thin that it essentially ceases to exist. Gradually, the atmospheric halo fades into the blackness of space.]]
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| ==See also==
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| * [[V-2]] rocket - the first human-built object to cross the Kármán line
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| ==References==
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| {{Reflist|1}}
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| ==External links==
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| *[http://www.fai.org/icare-records/100km-altitude-boundary-for-astronautics Article on the Kármán line] at the FAI website
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| *[http://www.srh.noaa.gov/srh/jetstream/atmos/layers.htm Layers of the Atmosphere – NOAA]
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| *[http://www.youtube.com/watch?v=ztjYDHO6HVU The Kármán Line] music video featuring NASA footage
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| {{Earth's atmosphere}}
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| {{Extreme motion}}
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| {{DEFAULTSORT:Karman line}}
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| [[Category:Outer space]]
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| [[Category:Atmosphere]]
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| [[Category:Aerospace]]
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| [[Category:Atmosphere of Earth]]
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Jerrie Swoboda is what somebody can call me I totally dig regarding name. What me and my family will always love is acting but I can't make it my profession really. The job I've been occupying for years is a real people manager. Guam is even I've always been having. You can sometimes find my website here: http://circuspartypanama.com
Here is my homepage clash of clans cheats android