75-555: (Redirected from Quiet Zone ) Quiet Zone may refer to: Radio quiet zone , an area where radio transmissions are restricted in order to protect a radio telescope or a communications station from radio frequency interference The United States National Radio Quiet Zone in West Virginia, Virginia and Maryland Quiet Zone (film) , 2015 experimental documentary short film about people living in this zone The area before and after
150-464: A barcode which is kept clear so that the barcode scanner can identify where the code starts and ends Railroad crossing quiet zone ; in North America, a section of railroad track where trains are not required to sound their horns when approaching a grade (or level) crossing The Quiet Zone/The Pleasure Dome , album by British progressive rock band Van der Graaf Generator Topics referred to by
225-424: A spacecraft must travel faster than a sub-orbital spaceflight along an arcing trajectory . The energy required to reach Earth orbital velocity at an altitude of 600 km (370 mi) is about 36 MJ /kg, which is six times the energy needed merely to climb to the corresponding altitude. The escape velocity required to pull free of Earth's gravitational field altogether and move into interplanetary space
300-471: A density of one proton per four cubic meters. The density of the universe is clearly not uniform; it ranges from relatively high density in galaxies—including very high density in structures within galaxies, such as planets, stars, and black holes —to conditions in vast voids that have much lower density, at least in terms of visible matter. Unlike matter and dark matter, dark energy seems not to be concentrated in galaxies: although dark energy may account for
375-519: A hazard to astronauts, even in low Earth orbit. They create aurorae seen at high latitudes in an oval surrounding the geomagnetic poles . xGeo space is a concept used by the US to refer to space of high Earth orbits , ranging from beyond geosynchronous orbit (GEO) at approximately 35,786 km (22,236 mi), out to the L2 Earth-Moon Lagrange point at 448,900 km (278,934 mi). This
450-507: A majority of the mass-energy in the universe, dark energy's influence is 5 orders of magnitude smaller than the influence of gravity from matter and dark matter within the Milky Way. Outer space is the closest known approximation to a perfect vacuum . It has effectively no friction , allowing stars, planets , and moons to move freely along their ideal orbits , following the initial formation stage. The deep vacuum of intergalactic space
525-502: A perigee as low as 80 to 90 km (50 to 56 mi), surviving for multiple orbits. At an altitude of 120 km (75 mi), descending spacecraft such as NASA 's Space Shuttle begin atmospheric entry (termed the Entry Interface), when atmospheric drag becomes noticeable, thus beginning the process of switching from steering with thrusters to maneuvering with aerodynamic control surfaces. The Kármán line , established by
600-636: A practical boundary have been proposed, ranging from 30 km (19 mi) out to 1,600,000 km (990,000 mi). High-altitude aircraft , such as high-altitude balloons have reached altitudes above Earth of up to 50 km. Up until 2021, the United States designated people who travel above an altitude of 50 mi (80 km) as astronauts. Astronaut wings are now only awarded to spacecraft crew members that "demonstrated activities during flight that were essential to public safety, or contributed to human space flight safety." In 2009, measurements of
675-481: A simulated Martian environment. The lithopanspermia hypothesis suggests that rocks ejected into outer space from life-harboring planets may successfully transport life forms to another habitable world. A conjecture is that just such a scenario occurred early in the history of the Solar System, with potentially microorganism -bearing rocks being exchanged between Venus, Earth, and Mars. The lack of pressure in space
750-643: A spacecraft; similarly, " space-based " means based in outer space or on a planet or moon. The size of the whole universe is unknown, and it might be infinite in extent. According to the Big Bang theory, the very early universe was an extremely hot and dense state about 13.8 billion years ago which rapidly expanded . About 380,000 years later the universe had cooled sufficiently to allow protons and electrons to combine and form hydrogen—the so-called recombination epoch . When this happened, matter and energy became decoupled, allowing photons to travel freely through
825-469: Is a continuous stream of charged particles emanating from the Sun which creates a very tenuous atmosphere (the heliosphere ) for billions of kilometers into space. This wind has a particle density of 5–10 protons /cm and is moving at a velocity of 350–400 km/s (780,000–890,000 mph). Interplanetary space extends out to the heliopause where the influence of the galactic environment starts to dominate over
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#1732855620612900-492: Is about 11,200 m/s (40,300 km/h; 25,100 mph). Orbiting spacecraft with a perigee below about 2,000 km (1,200 mi) are subject to drag from the Earth's atmosphere, which decreases the orbital altitude. The rate of orbital decay depends on the satellite's cross-sectional area and mass, as well as variations in the air density of the upper atmosphere. At altitudes above 800 km (500 mi), orbital lifetime
975-501: Is about five times the Moon's orbital distance , but which distance is also far less than the distance between Earth and any adjacent planet. Interplanetary space within the Solar System is the space between the eight planets, the space between the planets and the Sun, as well as that space beyond the orbit of the outermost planet Neptune where the solar wind remains active. The solar wind
1050-457: Is co-populated by groups of co-orbital Near-Earth Objects (NEOs), such as horseshoe librators and Earth trojans , with some NEOs at times becoming temporary satellites and quasi-moons to Earth. Deep space is defined by the United States government as all of outer space which lies further from Earth than a typical low-Earth-orbit, thus assigning the Moon to deep-space. Other definitions vary
1125-529: Is conventionally used as the start of outer space in space treaties and for aerospace records keeping. Certain portions of the upper stratosphere and the mesosphere are sometimes referred to as "near space". The framework for international space law was established by the Outer Space Treaty , which entered into force on 10 October 1967. This treaty precludes any claims of national sovereignty and permits all states to freely explore outer space . Despite
1200-586: Is different from Wikidata All article disambiguation pages All disambiguation pages Radio quiet zone A radio quiet zone is an area where radio transmissions are restricted in order to protect a radio telescope or a communications station from radio frequency interference . The Radio Regulations of the International Telecommunication Union (ITU) define interference as being detrimental to radio astronomy if it increases measurement uncertainty by 10%. In particular,
1275-496: Is divided into overlapping regions of space. Near-Earth space is the region of space extending from low Earth orbits out to geostationary orbits . This region includes the major orbits for artificial satellites and is the site of most of humanity's space activity. The region has seen high levels of space debris, sometimes dubbed space pollution , threatening any space activity in this region. Some of this debris re-enters Earth's atmosphere periodically. Although it meets
1350-438: Is free for all nation states to explore and is not subject to claims of national sovereignty, calling outer space the "province of all mankind". This status as a common heritage of mankind has been used, though not without opposition, to enforce the right to access and shared use of outer space for all nations equally, particularly non-spacefaring nations. It prohibits the deployment of nuclear weapons in outer space. The treaty
1425-487: Is located beyond the orbit of the Moon and therefore includes cislunar space. Translunar space is the region of lunar transfer orbits , between the Moon and Earth. Cislunar space is a region outside of Earth that includes lunar orbits , the Moon's orbital space around Earth and the Lagrange points . The region where a body's gravitational potential remains dominant against gravitational potentials from other bodies,
1500-475: Is measured in centuries. Below about 300 km (190 mi), decay becomes more rapid with lifetimes measured in days. Once a satellite descends to 180 km (110 mi), it has only hours before it vaporizes in the atmosphere. Space in proximity to the Earth is physically similar to the remainder of interplanetary space, but is home to a multitude of Earth–orbiting satellites and has been subject to extensive studies. For identification purposes, this volume
1575-422: Is measured in terms of the kinetic activity of the gas, as it is on Earth. The radiation of outer space has a different temperature than the kinetic temperature of the gas, meaning that the gas and radiation are not in thermodynamic equilibrium . All of the observable universe is filled with photons that were created during the Big Bang, which is known as the cosmic microwave background radiation (CMB). (There
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#17328556206121650-449: Is not devoid of matter , as it contains a few hydrogen atoms per cubic meter. By comparison, the air humans breathe contains about 10 molecules per cubic meter. The low density of matter in outer space means that electromagnetic radiation can travel great distances without being scattered: the mean free path of a photon in intergalactic space is about 10 km, or 10 billion light years. In spite of this, extinction , which
1725-648: Is often divided into two zones: an exclusion zone where all radio emissions are prohibited, and a larger coordination zone of up to 100 km where the power levels of radio transmissions are suitably limited so as not to interfere with the radio telescope. Formal radio quiet zones exist around many observatories, including the Murchison Radio-astronomy Observatory in Australia, the National Radio Astronomy Observatory and
1800-551: Is quite likely a correspondingly large number of neutrinos called the cosmic neutrino background . ) The current black body temperature of the background radiation is about 2.7 K (−455 °F). The gas temperatures in outer space can vary widely. For example, the temperature in the Boomerang Nebula is 1 K (−458 °F), while the solar corona reaches temperatures over 1,200,000–2,600,000 K (2,200,000–4,700,000 °F). Magnetic fields have been detected in
1875-631: Is slowed by the pressure containment of blood vessels, so some blood remains liquid. Swelling and ebullism can be reduced by containment in a pressure suit . The Crew Altitude Protection Suit (CAPS), a fitted elastic garment designed in the 1960s for astronauts, prevents ebullism at pressures as low as 2 kilopascals (0.3 psi). Supplemental oxygen is needed at 8 km (5 mi) to provide enough oxygen for breathing and to prevent water loss, while above 20 km (12 mi) pressure suits are essential to prevent ebullism. Most space suits use around 30–39 kilopascals (4–6 psi) of pure oxygen, about
1950-538: Is the absorption and scattering of photons by dust and gas, is an important factor in galactic and intergalactic astronomy . Stars, planets, and moons retain their atmospheres by gravitational attraction. Atmospheres have no clearly delineated upper boundary: the density of atmospheric gas gradually decreases with distance from the object until it becomes indistinguishable from outer space. The Earth's atmospheric pressure drops to about 0.032 Pa at 100 kilometres (62 miles) of altitude, compared to 100,000 Pa for
2025-447: Is the body's sphere of influence or gravity well, mostly described with the Hill sphere model. In the case of Earth this includes all space from the Earth to a distance of roughly 1% of the mean distance from Earth to the Sun, or 1.5 million km (0.93 million mi). Beyond Earth's Hill sphere extends along Earth's orbital path its orbital and co-orbital space. This space
2100-415: Is the expanse that exists beyond Earth's atmosphere and between celestial bodies . It contains ultra-low levels of particle densities , constituting a near-perfect vacuum of predominantly hydrogen and helium plasma , permeated by electromagnetic radiation , cosmic rays , neutrinos , magnetic fields and dust . The baseline temperature of outer space, as set by the background radiation from
2175-504: Is the most immediate dangerous characteristic of space to humans. Pressure decreases above Earth, reaching a level at an altitude of around 19.14 km (11.89 mi) that matches the vapor pressure of water at the temperature of the human body . This pressure level is called the Armstrong line , named after American physician Harry G. Armstrong . At or above the Armstrong line, fluids in
2250-554: The Andromeda Galaxy was first measured. Humans began the physical exploration of space later in the same century with the advent of high-altitude balloon flights . This was followed by crewed rocket flights and, then, crewed Earth orbit, first achieved by Yuri Gagarin of the Soviet Union in 1961. The economic cost of putting objects, including humans, into space is very high, limiting human spaceflight to low Earth orbit and
2325-476: The Big Bang , is 2.7 kelvins (−270 °C; −455 °F). The plasma between galaxies is thought to account for about half of the baryonic (ordinary) matter in the universe, having a number density of less than one hydrogen atom per cubic metre and a kinetic temperature of millions of kelvins . Local concentrations of matter have condensed into stars and galaxies . Intergalactic space takes up most of
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2400-467: The Bogotá Declaration , they claimed control of the segment of the geosynchronous orbital path corresponding to each country. These claims are not internationally accepted. An increasing issue of international space law and regulation has been the dangers of the growing number of space debris . A spacecraft enters orbit when its centripetal acceleration due to gravity is less than or equal to
2475-549: The Fédération Aéronautique Internationale , and used internationally by the United Nations , is set at an altitude of 100 km (62 mi) as a working definition for the boundary between aeronautics and astronautics. This line is named after Theodore von Kármán , who argued for an altitude where a vehicle would have to travel faster than orbital velocity to derive sufficient aerodynamic lift from
2550-551: The International Union of Pure and Applied Chemistry (IUPAC) definition of standard pressure . Above this altitude, isotropic gas pressure rapidly becomes insignificant when compared to radiation pressure from the Sun and the dynamic pressure of the solar wind . The thermosphere in this range has large gradients of pressure, temperature and composition, and varies greatly due to space weather . The temperature of outer space
2625-443: The Moon . On the other hand, uncrewed spacecraft have reached all of the known planets in the Solar System . Outer space represents a challenging environment for human exploration because of the hazards of vacuum and radiation . Microgravity has a negative effect on human physiology that causes both muscle atrophy and bone loss . The use of the short version space , as meaning 'the region beyond Earth's sky', predates
2700-815: The Sugar Grove Station in West Virginia, United States (the United States National Radio Quiet Zone ), the Itapetinga Radio Observatory in Brazil, and MeerKAT in South Africa as examples. The ITU has recommended designating two locations in outer space as radio quiet zones: the shielded zone on the Moon's far side , and the Sun-Earth Lagrangian point L 2 . Outer space Outer space (or simply space )
2775-471: The centrifugal acceleration due to the horizontal component of its velocity. For a low Earth orbit , this velocity is about 7,800 m/s (28,100 km/h; 17,400 mph); by contrast, the fastest piloted airplane speed ever achieved (excluding speeds achieved by deorbiting spacecraft) was 2,200 m/s (7,900 km/h; 4,900 mph) in 1967 by the North American X-15 . To achieve an orbit,
2850-500: The cosmic microwave background using satellites like the Wilkinson Microwave Anisotropy Probe . These observations indicate that the spatial geometry of the observable universe is " flat ", meaning that photons on parallel paths at one point remain parallel as they travel through space to the limit of the observable universe, except for local gravity. The flat universe, combined with the measured mass density of
2925-467: The immune system . Lesser symptoms include loss of body mass, nasal congestion, sleep disturbance, and puffiness of the face. During long-duration space travel, radiation can pose an acute health hazard . Exposure to high-energy, ionizing cosmic rays can result in fatigue, nausea, vomiting, as well as damage to the immune system and changes to the white blood cell count. Over longer durations, symptoms include an increased risk of cancer, plus damage to
3000-426: The zodiacal light . Interplanetary space contains the magnetic field generated by the Sun. There are magnetospheres generated by planets such as Jupiter, Saturn, Mercury and the Earth that have their own magnetic fields. These are shaped by the influence of the solar wind into the approximation of a teardrop shape, with the long tail extending outward behind the planet. These magnetic fields can trap particles from
3075-421: The Earth's magnetosphere and the solar wind. The inner boundary is the ionosphere . The variable space-weather conditions of geospace are affected by the behavior of the Sun and the solar wind; the subject of geospace is interlinked with heliophysics —the study of the Sun and its impact on the planets of the Solar System. The day-side magnetopause is compressed by solar-wind pressure—the subsolar distance from
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3150-452: The Sun. It is the space between the stars or stellar systems within a nebula or galaxy. Interstellar space contains an interstellar medium of sparse matter and radiation. The boundary between an astrosphere and interstellar space is known as an astropause . For the Sun, the astrosphere and astropause are called the heliosphere and heliopause. Approximately 70% of the mass of the interstellar medium consists of lone hydrogen atoms; most of
3225-418: The applicable regulation is known as ITU-R Recommendation RA.769, "Protection criteria used for radio astronomical measurements". Equipment that can cause interference includes mobile phones , television transmitters , and CB radios , as well as other electrical equipment . Quiet zones are located in areas that are sparsely populated, and may be enforced based on government legislation. A radio quiet zone
3300-732: The atmosphere to support itself, which he calculated to be at an altitude of about 83.8 km (52.1 mi). This distinguishes altitudes below as the region of aerodynamics and airspace , and above as the space of astronautics and free space . There is no internationally recognized legal altitude limit on national airspace, although the Kármán line is the most frequently used for this purpose. Objections have been made to setting this limit too high, as it could inhibit space activities due to concerns about airspace violations. It has been argued for setting no specified singular altitude in international law, instead applying different limits depending on
3375-498: The blood empties into the lungs to try to equalize the partial pressure gradient. Once the deoxygenated blood arrives at the brain, humans lose consciousness after a few seconds and die of hypoxia within minutes. Blood and other body fluids boil when the pressure drops below 6.3 kilopascals (1 psi), and this condition is called ebullism . The steam may bloat the body to twice its normal size and slow circulation, but tissues are elastic and porous enough to prevent rupture. Ebullism
3450-399: The body adjusts to the new environment. Longer-term exposure to weightlessness results in muscle atrophy and deterioration of the skeleton, or spaceflight osteopenia . These effects can be minimized through a regimen of exercise. Other effects include fluid redistribution, slowing of the cardiovascular system , decreased production of red blood cells , balance disorders, and a weakening of
3525-500: The case, in particular based on the craft and its purpose. Spacecraft have flown over foreign countries as low as 30 km (19 mi), as in the example of the Space Shuttle. The Outer Space Treaty provides the basic framework for international space law. It covers the legal use of outer space by nation states, and includes in its definition of outer space , the Moon, and other celestial bodies. The treaty states that outer space
3600-414: The center of the Earth is typically 10 Earth radii. On the night side, the solar wind stretches the magnetosphere to form a magnetotail that sometimes extends out to more than 100–200 Earth radii. For roughly four days of each month, the lunar surface is shielded from the solar wind as the Moon passes through the magnetotail. Geospace is populated by electrically charged particles at very low densities,
3675-447: The continually expanding space. Matter that remained following the initial expansion has since undergone gravitational collapse to create stars, galaxies and other astronomical objects, leaving behind a deep vacuum that forms what is now called outer space. As light has a finite velocity, this theory constrains the size of the directly observable universe. The present day shape of the universe has been determined from measurements of
3750-406: The cosmic rays upon the shielding produces additional radiation that can affect the crew. Further research is needed to assess the radiation hazards and determine suitable countermeasures. The transition between Earth's atmosphere and outer space lacks a well-defined physical boundary, with the air pressure steadily decreasing with altitude until it mixes with the solar wind. Various definitions for
3825-450: The definition of outer space, the atmospheric density inside low-Earth orbital space, the first few hundred kilometers above the Kármán line, is still sufficient to produce significant drag on satellites. Geospace is a region of space that includes Earth's upper atmosphere and magnetosphere . The Van Allen radiation belts lie within the geospace. The outer boundary of geospace is the magnetopause , which forms an interface between
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#17328556206123900-422: The direction and speed of ions in the atmosphere were made from a sounding rocket . The altitude of 118 km (73.3 mi) above Earth was the midpoint for charged particles transitioning from the gentle winds of the Earth's atmosphere to the more extreme flows of outer space. The latter can reach velocities well over 268 m/s (880 ft/s). Spacecraft have entered into a highly elliptical orbit with
3975-452: The drafting of UN resolutions for the peaceful uses of outer space, anti-satellite weapons have been tested in Earth orbit . The concept that the space between the Earth and the Moon must be a vacuum was first proposed in the 17th century after scientists discovered that air pressure decreased with altitude. The immense scale of outer space was grasped in the 20th century when the distance to
4050-436: The eyes, nervous system , lungs and the gastrointestinal tract . On a round-trip Mars mission lasting three years, a large fraction of the cells in an astronaut's body would be traversed and potentially damaged by high energy nuclei. The energy of such particles is significantly diminished by the shielding provided by the walls of a spacecraft and can be further diminished by water containers and other barriers. The impact of
4125-479: The harsh environment, several life forms have been found that can withstand extreme space conditions for extended periods. Species of lichen carried on the ESA BIOPAN facility survived exposure for ten days in 2007. Seeds of Arabidopsis thaliana and Nicotiana tabacum germinated after being exposed to space for 1.5 years. A strain of Bacillus subtilis has survived 559 days when exposed to low Earth orbit or
4200-596: The high energy range, the flux of electrons is only about 1% of that of protons. Cosmic rays can damage electronic components and pose a health threat to space travelers. Smells produced returning from low Earth orbit extravehicular activity have a burned/metallic odor, similar to the scent of arc welding fumes, resulting from oxygen in low Earth orbit around the ISS, which clings to suits and equipment. Other regions of space could have very different smells, like that of different alcohols in molecular clouds . Despite
4275-610: The international co-operation in the peaceful uses of outer space and preventing an arms race in space. Four additional space law treaties have been negotiated and drafted by the UN's Committee on the Peaceful Uses of Outer Space . Still, there remains no legal prohibition against deploying conventional weapons in space, and anti-satellite weapons have been successfully tested by the USA, USSR, China, and in 2019, India. The 1979 Moon Treaty turned
4350-588: The jurisdiction of all heavenly bodies (including the orbits around such bodies) over to the international community. The treaty has not been ratified by any nation that currently practices human spaceflight. In 1976, eight equatorial states (Ecuador, Colombia, Brazil, The Republic of the Congo, Zaire, Uganda, Kenya, and Indonesia) met in Bogotá, Colombia: with their "Declaration of the First Meeting of Equatorial Countries", or
4425-442: The large pressure differential between inside and outside the chest. Even if the subject's airway is fully open, the flow of air through the windpipe may be too slow to prevent the rupture. Rapid decompression can rupture eardrums and sinuses, bruising and blood seep can occur in soft tissues, and shock can cause an increase in oxygen consumption that leads to hypoxia . As a consequence of rapid decompression, oxygen dissolved in
4500-404: The magnetic field and particle flux from the Sun. The distance and strength of the heliopause varies depending on the activity level of the solar wind. The heliopause in turn deflects away low-energy galactic cosmic rays, with this modulation effect peaking during solar maximum. The volume of interplanetary space is a nearly total vacuum, with a mean free path of about one astronomical unit at
4575-518: The most distant high-z sources, indicating the presence of magnetic fields. Outside a protective atmosphere and magnetic field, there are few obstacles to the passage through space of energetic subatomic particles known as cosmic rays. These particles have energies ranging from about 10 eV up to an extreme 10 eV of ultra-high-energy cosmic rays . The peak flux of cosmic rays occurs at energies of about 10 eV, with approximately 87% protons, 12% helium nuclei and 1% heavier nuclei. In
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#17328556206124650-525: The motions of which are controlled by the Earth's magnetic field . These plasmas form a medium from which storm-like disturbances powered by the solar wind can drive electrical currents into the Earth's upper atmosphere. Geomagnetic storms can disturb two regions of geospace, the radiation belts and the ionosphere. These storms increase fluxes of energetic electrons that can permanently damage satellite electronics, interfering with shortwave radio communication and GPS location and timing. Magnetic storms can be
4725-403: The orbital distance of the Earth. This space is not completely empty, and is sparsely filled with cosmic rays, which include ionized atomic nuclei and various subatomic particles. There is gas, plasma and dust, small meteors , and several dozen types of organic molecules discovered to date by microwave spectroscopy . A cloud of interplanetary dust is visible at night as a faint band called
4800-439: The remainder consists of helium atoms. This is enriched with trace amounts of heavier atoms formed through stellar nucleosynthesis . These atoms are ejected into the interstellar medium by stellar winds or when evolved stars begin to shed their outer envelopes such as during the formation of a planetary nebula . The cataclysmic explosion of a supernova propagates shock waves of stellar ejecta outward, distributing it throughout
4875-640: The same as the partial pressure of oxygen at the Earth's surface. This pressure is high enough to prevent ebullism, but evaporation of nitrogen dissolved in the blood could still cause decompression sickness and gas embolisms if not managed. Humans evolved for life in Earth gravity , and exposure to weightlessness has been shown to have deleterious effects on human health. Initially, more than 50% of astronauts experience space motion sickness . This can cause nausea and vomiting, vertigo , headaches, lethargy , and overall malaise. The duration of space sickness varies, but it typically lasts for 1–3 days, after which
4950-417: The same term [REDACTED] This disambiguation page lists articles associated with the title Quiet zone . If an internal link led you here, you may wish to change the link to point directly to the intended article. Retrieved from " https://en.wikipedia.org/w/index.php?title=Quiet_zone&oldid=1075302235 " Category : Disambiguation pages Hidden categories: Short description
5025-468: The solar wind and other sources, creating belts of charged particles such as the Van Allen radiation belts. Planets without magnetic fields, such as Mars, have their atmospheres gradually eroded by the solar wind. Interstellar space is the physical space outside of the bubbles of plasma known as astrospheres , formed by stellar winds originating from individual stars, or formed by solar wind emanating from
5100-625: The space around just about every class of celestial object. Star formation in spiral galaxies can generate small-scale dynamos , creating turbulent magnetic field strengths of around 5–10 μ G . The Davis–Greenstein effect causes elongated dust grains to align themselves with a galaxy's magnetic field, resulting in weak optical polarization . This has been used to show ordered magnetic fields that exist in several nearby galaxies. Magneto-hydrodynamic processes in active elliptical galaxies produce their characteristic jets and radio lobes . Non-thermal radio sources have been detected even among
5175-409: The starting point of deep-space from, "That which lies beyond the orbit of the moon," to "That which lies beyond the farthest reaches of the Solar System itself." The International Telecommunication Union responsible for radio communication , including with satellites, defines deep-space as, "distances from the Earth equal to, or greater than, 2 million km (1.2 million mi)," which
5250-407: The throat and lungs boil away. More specifically, exposed bodily liquids such as saliva, tears, and liquids in the lungs boil away. Hence, at this altitude, human survival requires a pressure suit, or a pressurized capsule. Out in space, sudden exposure of an unprotected human to very low pressure , such as during a rapid decompression, can cause pulmonary barotrauma —a rupture of the lungs, due to
5325-427: The universe and the accelerating expansion of the universe , indicates that space has a non-zero vacuum energy , which is called dark energy . Estimates put the average energy density of the present day universe at the equivalent of 5.9 protons per cubic meter, including dark energy, dark matter, and baryonic matter (ordinary matter composed of atoms). The atoms account for only 4.6% of the total energy density, or
5400-478: The use of full term "outer space", with the earliest recorded use of this meaning in an epic poem by John Milton called Paradise Lost , published in 1667. The term outward space existed in a poem from 1842 by the English poet Lady Emmeline Stuart-Wortley called "The Maiden of Moscow", but in astronomy the term outer space found its application for the first time in 1845 by Alexander von Humboldt . The term
5475-399: The volume of the universe , but even galaxies and star systems consist almost entirely of empty space. Most of the remaining mass-energy in the observable universe is made up of an unknown form, dubbed dark matter and dark energy . Outer space does not begin at a definite altitude above Earth's surface. The Kármán line , an altitude of 100 km (62 mi) above sea level ,
5550-457: Was eventually popularized through the writings of H. G. Wells after 1901. Theodore von Kármán used the term of free space to name the space of altitudes above Earth where spacecrafts reach conditions sufficiently free from atmospheric drag, differentiating it from airspace , identifying a legal space above territories free from the sovereign jurisdiction of countries. " Spaceborne " denotes existing in outer space, especially if carried by
5625-647: Was passed by the United Nations General Assembly in 1963 and signed in 1967 by the Union of Soviet Socialist Republics (USSR), the United States of America (USA), and the United Kingdom (UK). As of 2017, 105 state parties have either ratified or acceded to the treaty. An additional 25 states signed the treaty, without ratifying it. Since 1958, outer space has been the subject of multiple United Nations resolutions. Of these, more than 50 have been concerning
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