Outer space , or just space , is an expanse outside the Earth and between celestial bodies. The outer space is not completely empty - it is a hard vacuum that contains low particle density, especially the hydrogen and helium plasmas as well as electromagnetic radiation, magnetic fields, neutrino, dust, and cosmic rays. The base temperature, as determined by the background radiation of the Big Bang, is 2.7 kelvin (-270.45 Â ° C; -454,81 Â ° F). Plasma between galaxies accounts for about half the baryon (ordinary) matter in the universe; it has a hydrogen atom density of less than one per cubic meter and a temperature of millions of kelvins; Local concentrations of these plasmas have been condensed into stars and galaxies. Studies show that 90% of the mass in most galaxies is in unknown form, called dark matter, which interacts with other matter through gravity but not electromagnetic forces. Observations show that most of the mass-energy in the observed universe is a poorly understood vacuum energy, which astronomers label dark energy. Intergalactic space takes up most of the volume of the universe, but even galaxies and star systems are almost entirely made up of empty space.
Outer space does not begin at a definite altitude above the earth's surface. However, the KÃÆ'¡rmÃÆ'¡n line, at an altitude of 100 km (62 m) above sea level, is conventionally used as the beginning of the outer space in the space agreement and for the storage of aerospace records. The international space law framework is defined by the Space Agreement, which came into force on October 10, 1967. This treaty impedes the claim of national sovereignty and allows all countries to freely explore outer space. Despite drafting UN resolutions for peaceful space use, anti-satellite weapons have been tested in Earth orbit.
Humans began the physical exploration of space during the 20th century with the rise of high-altitude balloon flights, followed by the launch of manned rockets. The Earth's orbit was first achieved by Yuri Gagarin of the Soviet Union in 1961, and the unmanned spacecraft has since reached all the known planets in the Solar System. Due to the high cost of going into space, manned space is limited to low Earth orbit and Moon.
Outer space is a challenging environment for human exploration because of the double dangers of vacuum and radiation. Microgravity also has a negative effect on human physiology that causes muscle atrophy and bone loss. In addition to these health and environmental concerns, the economic cost of placing objects, including humans, into space is very high.
Video Outer space
Discovery
In 350 BC, the Greek philosopher Aristotle suggested that nature hates the void, a principle known as horror vacui. This concept is built on a 5th century ontological argument by the Greek philosopher Parmenides, who denies the possibility of a void in space. Based on this idea that a vacuum can not exist, in the West it is widely held for centuries that space can not be empty. Until the 17th century, the French philosopher Renà © ¨ Descartes argued that the whole space should be filled.
In ancient China, the 2nd century astronomer Zhang Heng became convinced that space must be infinite, extending far beyond the mechanisms that support the Sun and the stars. The surviving books of the school of HsÃÆ'¼an Yeh say that the sky is infinite, "empty and empty of matter". Likewise, "sun, moon, and star companies float in empty space, move or stand still".
Italian scientist Galileo Galilei knows that air has mass and becomes subject to gravity. In 1640, he showed that steady forces suppress the formation of a vacuum. However, it would remain for his student Evangelista Torricelli to create a device that would produce a partial vacuum in 1643. This experiment yielded the first mercury barometer and created a scientific sensation in Europe. The French mathematician Blaise Pascal reasoned that if the mercury column is supported by air, then the column should be shorter at higher altitudes where air pressure is lower. In 1648, his brother-in-law, Florin PÃÆ' Â © rier, repeated the experiment on the Puy de DÃÆ'Â'me mountain in central France and found that the column was three inches shorter. This drop in pressure is further demonstrated by bringing a half-full balloon up the mountain and watching it gradually expand, then contracting as it descends.
In 1650, the German scientist Otto von Guericke built the first vacuum pump: a device which would further refute the principle of horror vacui . He correctly noted that the Earth's atmosphere surrounds the planet like a shell, with density decreasing gradually with altitude. He concluded that there must be a vacuum between Earth and the Moon.
Back in the fifteenth century, German theologian Nicolaus Cusanus speculated that the Universe has no center and perimeter. He believed that the Universe, though not infinite, can not be considered limited because it has no limits on which it can be enclosed. These ideas led to speculation about the infinite dimensions of space by Italian philosopher Giordano Bruno in the 16th century. He extends Copernicus's heliocentric cosmology to the infinite universe concept which is full of the substance he calls ether, which is not against the motion of celestial bodies. The English philosopher William Gilbert arrived at the same conclusion, arguing that the stars are visible to us simply because they are surrounded by thin aether or emptiness. This aether concept derives from ancient Greek philosophers, including Aristotle, who regarded it as the medium through which heavenly bodies move.
The concept of a Universe filled with luminiferous ether remained a fad among several scientists up to the beginning of the 20th century. This form of ether is seen as a medium in which light can propagate. In 1887, the Michelson-Morley experiment tried to detect Earth's motion through this medium by searching for changes in the speed of light depending on the direction of planetary motion. However, a zero result indicates something is wrong with the concept. The idea of ​​aether luminiferous is then abandoned. Replaced by Albert Einstein's special theory of relativity, which states that the speed of light in a vacuum is a constant constant, independent of the motion of the observer or the frame of reference.
The first professional astronomer to support the unlimited concept of the universe was the Englishman Thomas Digges in 1576. But the scale of the universe remained unknown until the first successful measurement of distance to the nearest star in 1838 by the German astronomer Friedrich Bessel. He showed that 61 Cygni star has a parallax of only 0.31 seconds arc (compared to the modern value of 0.287?). This corresponds to a distance of more than 10 light years. In 1917, Heber Curtis noted that the novae in the spiral nebula, on average, 10 magnitude dimmer than the galactic nova, indicates that the former is 100 times farther. The distance to the Andromeda Galaxy was determined in 1923 by American astronomer Edwin Hubble by measuring the cepheid variable brightness in the galaxy, a new technique invented by Henrietta Leavitt. It establishes that the Andromeda galaxy, and by extension of all galaxies, lies deep beyond the Milky Way.
The earliest estimate of the temperature of outer space by the Swiss physicist Charles ÃÆ'â € °. Guillaume in 1896. Using an approximate radiation from a background star, he concluded that space should be heated to a temperature of 5-6Ã, K. The British physicist Arthur Eddington made a similar calculation to lower the temperature of 3.18Ã, Â ° K in 1926. German physicist Erich Regener used the total energy measured from cosmic rays to estimate the intergalactic temperature of 2.8 K in 1933.
The modern concept of outer space is based on the cosmology of "Big Bang", first proposed in 1931 by Belgian physicist Georges LemaÃÆ'®tre. This theory states that the universe comes from a very dense form which has since undergone a continuous expansion. The background energy released during early expansion has steadily declined in density, leading to a 1948 prediction by American physicists Ralph Alpher and Robert Herman of 5 Â ° K for room temperature.
The term outer space was used in 1842 by the English poet Lady Emmeline Stuart-Wortley in his poem "The Maiden of Moscow". The expression outer space was used as an astronomical term by Alexander von Humboldt in 1845. It was later popularized in the writings of HG Wells in 1901. The term is short space older, used to mean an area beyond the sky at John Milton Paradise Lost in 1667.
Maps Outer space
Formation and status
According to the Big Bang theory, the very early universe was a very hot and dense country about 13.8 billion years ago that thrived. About 380,000 years later the universe has cooled enough to allow protons and electrons to join and form hydrogen - the so-called recombination age. When this happens, matter and energy become separated, allowing photons to travel freely through the growing space. The material that follows the initial expansion has since undergone a gravitational collapse to create stars, galaxies and other astronomical objects, leaving a deep vacuum that forms what is now called outer space. Because light has a limited speed, it also limits the size of the observable universe directly. This leaves open the question of whether the universe is limited or unlimited.
The present day shape of the universe has been determined from cosmic microwave wave measurements using satellites such as the Wilkinson Microwave Anisotropy Probe. This observation shows that the observable geometry of the observable universe is "flat", meaning that photons in parallel paths at one point remain parallel as they travel through space to the observable limits of the universe, except for local gravity. The flat universe, combined with the measured mass density of the universe and the acceleration of the expansion of the universe, shows that space has a nonzero vacuum energy, called dark energy.
Estimates put the average energy density of the universe currently equivalent to 5.9 protons per cubic meter, including dark energy, dark matter, and baryonic matter (ordinary matter composed of atoms). The atomic account is only 4.6% of the total energy density, or the density of one proton per four cubic meters. The density of the universe, however, is clearly not uniform; it ranges from relatively high densities in galaxies - including very high densities in structures in galaxies, such as planets, stars, and black holes - for conditions in vast cavities that have much lower densities, at least in terms of visible matter. Unlike dark matter and matter, dark energy does not seem to be concentrated in the galaxy: although dark energy can account for most of the mass energy in the universe, the effect of dark energy is 5 orders of magnitude smaller than the gravitational influence of dark matter and matter in the Milky Way.
Environment
Outer space is the closest approximation known to a perfect vacuum. Effectively there is no friction, allowing stars, planets, and moon to move freely along their ideal orbit, following the initial stages of formation. However, even the vacuum of deep intergalactic space is not free of matter, as it contains several hydrogen atoms per cubic meter. By comparison, human air breathing contains about 10 25 molecules per cubic meter. The low density of matter in space means that electromagnetic radiation can travel a great distance without dispersion: the average free path of photons in the intergalactic space is about 10 km, or 10 billion light years. Apart from this, the extinction, which is the absorption and scattering of photons by dust and gases, is an important factor in galaxy astronomy and intergalactic.
Stars, planets, and moons retain their atmosphere with gravitational attraction. The atmosphere does not have a clearly delineated upper bound: atmospheric gas density gradually decreases with distance from the object until it becomes indistinguishable from outer space. The Earth's atmospheric pressure drops to approximately 0.032 Pa at 100 kilometers (62 miles) from a height, compared to 100,000 Pa for the International Union of Pure and Applied Chemistry (IUPAC) standard definition. Above this altitude, isotropic gas pressure quickly becomes insignificant when compared to the radiation pressure of the Sun and the dynamic pressure of the solar wind. The atmosphere in this range has a large pressure gradient, temperature and composition, and varies greatly with space weather.
The space temperature is measured in terms of the kinetic activity of the gas, as in Earth. However, space radiation has a temperature different from the kinetic temperature of the gas, which means that the gas and radiation are not in thermodynamic equilibrium. All observable universes are filled with photons created during the Big Bang, known as cosmic microwave cosmic background (CMB). (There is most likely a large number of neutrinos called cosmic neutrino backgrounds.) The current black body temperature from background radiation is about 3 Â ° K (-270 Â ° C; -454 Â ° F). Gas temperatures in outer space are at least always CMB temperatures but can be much higher. For example, the sun's corona reaches a temperature of more than 1.2-2.6 million K.
The magnetic field has been detected in the space around almost every class of celestial bodies. The formation of stars in a spiral galaxy can produce small-scale dynamics, creating a turbulent magnetic field strength of about 5-10? G. The Davis-Greenstein effect causes elongated grain dust to conform to the galactic magnetic field, resulting in weak optical polarization. It has been used to indicate which magnetic field is ordered to exist in some nearby galaxies. The magneto-hydrodynamic process of active elliptical galaxies produces distinctive radiation and radio lobes. Non-thermal radio sources have been detected even among the farthest, high-z sources, indicating the presence of a magnetic field.
Outside the protective atmosphere and magnetic field, there are several obstacles to pass through the space of energetic subatomic particles known as cosmic rays. These particles have energy ranging from about 10 6 eV to extreme 10 20 Ã, eV of ultra-high-energy cosmic rays. The peak cosmic ray flux occurs at an energy of about 10 9 Ã, eV, with about 87% of protons, 12% helium nuclei and 1% heavier nuclei. In high energy ranges, the electron flux is only about 1% of the proton. Cosmic rays can damage electronic components and pose a health threat to space travelers. According to astronauts, like Don Pettit, the room has a burning/metallic smell that sticks to their clothes and equipment, similar to the scent of a welding torch.
Despite the harsh environment, several life forms have been found that can withstand extreme space conditions for a long time. The moss species brought in the ESA BIOPAN facility survived the 10-day exposure in 2007. Seeds Arabidopsis thaliana and Nicotiana tabacum germinated after exposure to space for 1.5 years. The Effects on the human body
Even at relatively low altitudes in Earth's atmosphere, its condition is hostile to the human body. The height at which atmospheric pressure fits with the pressure of water vapor at human body temperature is called the Armstrong line, named after American physician Harry G. Armstrong. Located at an altitude of about 19.14 km (11.89 mi). At or above the Armstrong line, the fluid in the throat and lungs boils. More specifically, exposed to body fluids such as saliva, tears, and fluid in the lungs boils. Therefore, at this altitude, human survival requires a pressure setting, or a pressurized capsule.
Once in space, the sudden exposure of humans unprotected to very low pressures, such as during rapid decompression, can cause pulmonary barotrauma - rupture of the lung, due to the large pressure differences 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 rupture. Rapid decompression can damage the eardrum and sinus, bruising and blood seeping can occur in soft tissue, and shock can lead to increased oxygen consumption leading to hypoxia.
As a consequence of rapid decompression, dissolved oxygen in the blood boils down to the lungs to try to equalize the partial pressure gradient. Once deoxygenated blood arrives in the brain, people lose consciousness after a few seconds and die from hypoxia within minutes. Blood and other body fluids boil when the pressure falls below 6.3 kPa, and this condition is called ebullism. Steam can swell the body to twice the normal size and slow circulation, but the tissue is sufficiently elastic and porous to prevent rupture. Ebullism is slowed by the pressure of blood vessel arrest, so some of the blood remains liquid. Swelling and ebullism can be reduced by containment in pressure settings. The Crew Altitude Protection Suit (CAPS), a fitted elastic garment designed in 1960 for astronauts, prevents ebullism at pressures as low as 2 kPa. Additional oxygen is required at 8 km (5.0 mi) to provide sufficient oxygen for breathing and to prevent water loss, while over 20 km (12 mi) of suitable pressure is essential to prevent ebullism. Most space suits use about 30-39 kPa of pure oxygen, almost equal to the surface of the Earth. This pressure is high enough to prevent ebullism, but evaporation of dissolved nitrogen in the blood can still cause decompression and gas embolism if not managed.
Humans evolved to live in Earth's gravity, and weightless exposure has been shown to have devastating effects on human health. Initially, more than 50% of astronauts experienced space travel. This can cause nausea and vomiting, vertigo, headache, lethargy, and malaise as a whole. Duration of space diseases varies, but usually lasts 1-3 days, after which the body adjusts to the new environment. Long term exposure to weightless results results in muscle atrophy and skeletal damage, or osteopenia spaceflight. These effects can be minimized through a sports regimen. Other effects include fluid redistribution, slow cardiovascular system, decreased red blood cell production, impaired balance, and weakening of the immune system. Lower symptoms include loss of body mass, nasal congestion, sleep disturbances, and swelling of the face.
For long space travel, radiation can pose an acute health hazard. Exposure to high-energy ionizing cosmic rays can cause fatigue, nausea, vomiting, as well as immune system damage and changes in white blood cell counts. Over a longer period of time, symptoms include an increased risk of cancer, plus damage to the eyes, nervous system, lungs and digestive tract. On Mars's mission that lasts for three years, most of the cells in the astronaut body will be traversed and potentially damaged by high energy nuclei. Fortunately, the energy of the particles is significantly reduced by the shield provided by the wall of a spacecraft and can be further reduced by water containers and other obstructions. However, the impact of cosmic rays on the shield produces additional radiation that can affect the crew. Further research is needed to assess the radiation hazard and determine appropriate mitigation measures.
Boundary
There is no clear boundary between the atmosphere and the Earth's space, because the atmospheric density gradually decreases as the altitude increases. There are some standard setting limits, namely:
In 2009, scientists reported detailed measurements with Supra-Thermal Ion Imager (an instrument that measures the direction and speed of ions), allowing them to set limits at 118 km (73 mi) above Earth. The boundary represents the midpoint of a gradual transition over tens of kilometers of relatively gentle wind from Earth's atmosphere to a stronger stream of charged particles in space, which can reach speeds of over 268 m/s (600 mph).
Legal status
The Outer Space Treaty provides a basic framework for international space law. This includes the use of space law by nation states, and is included in the definition of outer space of the Moon and other celestial bodies. The agreement states that space is free for all nation states to be explored and not subject to claims of national sovereignty. It also prohibits the spread of nuclear weapons in space. The treaty was adopted by the UN General Assembly in 1963 and signed in 1967 by the Soviet Union, the United States and Britain. By 2017, 105 States parties have ratified or acceded to the treaty. An additional 25 countries signed the agreement, without ratifying it.
Since 1958, outer space has been the subject of numerous United Nations resolutions. Of this amount, over 50 have paid close attention to international cooperation in peaceful space usage and preventing an arms race in outer space. Four additional space law treaties have been negotiated and drafted by the UN Committee on Peaceful Space Use. However, there remains no legal prohibition against conventional weapon deployment in outer space, and anti-satellite weapons have been successfully tested by the US, USSR, and China. The 1979 Treaty changed the jurisdiction of all heavenly bodies (including orbit around them) into the international community. However, this agreement has not been ratified by any country currently practicing manned space.
In 1976, eight equatorial countries (Ecuador, Colombia, Brazil, Congo, Zaire, Uganda, Kenya, and Indonesia) met in BogotÃÆ'¡, Colombia. With the "Declaration of the First Encounter of the Equator Country", or "BogotÃÆ'¡" Declaration, they claim control of the geosynchronous orbital line segments associated with each country. This claim is not accepted internationally.
Earth Orbit
A spacecraft enters orbit when its centripetal acceleration due to gravity is less than or equal to centrifugal acceleration due to the horizontal component of its speed. For low Earth orbit, this speed is about 7,800 m/s (28,100 km/h, 17,400 mph); In contrast, the fastest manned speed aircraft ever achieved (excluding speeds achieved by the deorbiting spacecraft) was 2,200 m/s (7,900 km/h, 4,900 mph) in 1967 by North America X-15.
To reach orbit, the spacecraft must travel faster than sub-orbital space. The energy required to reach Earth's orbital speed at an altitude of 600 km (370 mi) is about 36 MJ/kg, which means six times the energy needed just to climb to the appropriate height. Spacecraft with a perigee below about 2,000 km (1,200 mi) can be dragged from Earth's atmosphere, which lowers the orbital height. The degree of orbital damage depends on the area of ​​cross section and the mass of the satellite, as well as the variations in the air density of the upper atmosphere. Below about 300 km (190 million), decay becomes faster with lifespan measured within days. After satellite down to 180 km (110 mi), just a few hours before evaporating in the atmosphere. The escape velocity required to pull freely from the Earth's gravitational field altogether and move into interplanetary space is about 11,200 m/s (40,300 km/h; 25,100 mph).
Areas
Space is a partial vacuum: its different region is defined by the various atmospheres and "winds" that dominate in it, and extends to the point where the wind gives way to them outside. Geospace extends from Earth's atmosphere to the outside of the Earth's magnetic field, where it gives way to the solar wind from interplanetary space. The interplanetary space extends into the heliopause, where the solar wind gives way to the interstellar medium wind. The interstellar space then continues to the edge of the galaxy, where it fades into the intergalactic void.
Geospace
Geospace is a space region near the Earth, including the upper atmosphere and magnetosphere. Van Allen's radiation belt is located within geospace. The outer boundary of geospace is the magnetopause, which forms the interface between the Earth's magnetosphere and the solar wind. The inner limit is the ionosphere. The geo-space variable weather conditions are influenced by the behavior of the Sun and the solar wind; the subject of geospace is intertwined with heliophysics - the study of the Sun and its impact on the planets of the Solar System.
The day-side magnetopause is compressed by the solar-wind pressure - the subsolar distance of the Earth's center is usually 10 Earth radii. On the night side, the solar wind stretches the magnetosphere to form a magnetotail that sometimes extends to more than 100-200 Earth radii. For about four days each month, the moon's surface is protected from the solar wind when the Moon passes through magnetotail.
Geospace is inhabited by electrically charged particles with very low densities, motions controlled by the Earth's magnetic field. These plasmas form a medium from which disturbances such as storms powered by the solar wind can propel an electric current into the Earth's upper atmosphere. Geomagnetic storms can disrupt two geospace regions, radiation belts and ionosphere. This storm increases the flow of energetic electrons that can damage satellite electronics permanently, disrupting shortwave radio communications and GPS location and time. Magnetic storms can also be a hazard to astronauts, even in low Earth orbit. They also make the aurora visible at high latitudes in the ovals that surround the geomagnetic poles.
Although it meets the definition of outer space, atmospheric density within the first few hundred kilometers above the KÃÆ'¡rmÃÆ'¡n line is still sufficient to produce significant barriers to satellites. This region contains material left over from previous manned and unmanned launches that could potentially harm the spacecraft. Some of these debris re-enter the Earth's atmosphere periodically.
Cislunar Room
Earth's gravity keeps the Moon in orbit with an average distance of 384,403 km (238,857 mi). The region outside the Earth's atmosphere and extends outward from the orbit of the Moon, including the Lagrangian point, is sometimes referred to as cislunar space .
The region of space where the gravity of the earth remains dominant to the gravitational impairment of the Sun is called the Hill ball. It extends deep into the translunar space up to a distance of about 1% of the average distance from Earth to the Sun, or 1.5 million km (0.93 million).
Outer space has a different definition of where it started. It has been defined by the government of the United States and others as any territory outside the cislunar space. The International Telecommunication Union responsible for radio communications (including satellites) defines the beginning of space in about 5 times the distance ( 2 ÃÆ' - 10 6 km ).
Interplanetary space
Interplanetary space is defined by the solar wind, the continuous flow of charged particles that originate from the Sun creating a very heliosphere for billions of kilometers into space. This wind has a particle density of 5-10 proton/cm 3 and moves at a speed of 350-400 km/s (780,000-890,000 mph). The interplanetary space extends to heliopause in which the galaxy's environmental influence begins to dominate over the magnetic field and the particle flux of the Sun. The distance and strength of heliopause vary depending on the level of solar wind activity.
The volume of interplanetary space is total hollow, with an average free path of about one astronomical unit at Earth's orbital distance. However, this space is not completely empty, and rarely filled with cosmic rays, which include ionized atomic nuclei and various subatomic particles. There is also gas, plasma and dust, small meteors, and several dozen different types of organic molecules found to date by microwave spectroscopy. An inter-planetary dust cloud is visible at night as a weak band called the zodiac light.
The interplanetary space contains a magnetic field generated by the Sun. There is also a magnetosphere generated by planets such as Jupiter, Saturn, Mercury and Earth which has its own magnetic field. It is formed by the influence of the solar wind into an approximate shape of the teardrop, with a long tail extending out behind the planet. This magnetic field can trap particles from the solar wind and other sources, creating belts of charged particles such as the Van Allen radiation belt. Planets without a magnetic field, such as Mars, have an atmosphere gradually eroded by the solar wind.
interstellar space
The interstellar space is the physical space within the galaxy beyond the influence of every star on the plasma covered. The contents of interstellar space are called interstellar mediums. Approximately 70% of the mass of the interstellar medium consists of a single hydrogen atom; most of the rest is made up of helium atoms. This is enriched by the heavier number of traces of atoms formed through star nucleosynthesis. These atoms are released into the interstellar medium by the star wind or when the evolved star begins to release its outer envelope as during the formation of the planetary nebula. The massive explosion of a supernova produces a widespread shock wave consisting of an ejection material that enriches the medium. The density of matter in the interstellar medium can vary greatly: on average it is about 10 6 particles per m 3 , but cold molecular clouds can withstand 10 8 -10 12 per m 3 .
A number of molecules exist in the interstellar space, as do the small 0.1 m dust particles. The number of molecules discovered through radio astronomy continues to increase at a rate of about four new species per year. Large areas of higher density known as molecular clouds allow for chemical reactions, including the formation of organic polyatomic species. Most of these chemicals are driven by collisions. Energetic cosmic rays penetrate cold and dense clouds and ionize hydrogen and helium, producing, for example, in trihydrogen cations. An ionized helium atom can then divide the relatively abundant carbon monoxide to produce ionized carbon, which in turn can cause organic chemical reactions.
The local interstellar medium is the space region within 100 parsecs (pc) of the Sun, which is attractive both for its proximity and for its interaction with the Solar System. This volume almost coincides with the space region known as the Local Bubble, which is characterized by a lack of thick and cold clouds. It forms a cavity in the Orion Arm of the Milky Way, with solid molecular clouds located along the border, like those in the constellations Ophiuchus and Taurus. (The actual distance to this cavity limit varies from 60 to 250 pc or more.) This volume contains about 10 stars 4 -10 5 and the local interstellar gas balancer of the astrospheres surround these stars, with the volume of each ball varying depending on the local density of the interstellar medium. The Local Bubble contains dozens of warm interstellar clouds with temperatures up to 7,000 K and a 0.5-5 pc radius.
As the stars move at a fairly high speed, their astrospheres can produce arc shafts as they collide with the interstellar medium. For decades, it was assumed that the Sun had a collision. In 2012, data from Interstellar Boundary Explorer (IBEX) and NASA's Voyager probe show that the Sun's bow shock does not exist. Instead, these authors argue that subsonic arc waves define the transition from the flow of solar wind to the interstellar medium. The arc shock is the third boundary of the astrosphere after shock termination and astropause (called heliopause in the Solar System).
Intergalactic space
Intergalactic space is the physical space between galaxies. Studies of the large-scale distribution of galaxies show that the Universe has a foam-like structure, with clusters and clusters of galaxies lying along filaments that occupy about one-tenth of the total space. The rest form large cavities that are largely empty of galaxies. Typically, a vacancy includes the distance (10-40) h -1 Mpc, where h is the Hubble constant in units 100 km s -1 Mpc -1 .
Around and stretches between galaxies, there is a clarified plasma arranged in the galactic filamentous structure. This material is called intergalactic medium (IGM). IGM density is 5 to 200 times the average density of the universe. It consists mostly of ionized hydrogen; the plasma consisting of the same number of electrons and protons. When the gas falls into the intergalactic medium of voids, it heats to a temperature of 10 5 K to 10 7 Ã, K, which is high enough that there is a collision between atoms. has enough energy to cause the electrons to bond to break away from the hydrogen nuclei; this is why IGM is ionized. At this temperature, it is called hot-warm intergalactic medium (WHIM). (Although plasma is very hot by terrestrial standards, 10 5 K is often called "warm" in astrophysics.) Computer simulations and observations show that up to half of the atomic matter in the universe may exist in warm, this. When the gas falls from the WHIM filament structure into the cluster of galaxies at the junction of cosmic filaments, it can heat up even more, reaching the temperature of 10 8 K and above in so-called intracluster media.
Exploration and apps
For much of human history, space is explored by observations made from the Earth's surface - initially with the naked eye and then by telescopes. Prior to the advent of reliable rocket technology, the closest that humans came to reach outer space was through the use of balloon flights. In 1935, the United States II manned balloon flight had reached a height of 22 km (14 mi). This was greatly exceeded in 1942 when the launch of the German A-4 rocket climbed to a height of about 80 km (50 mi). In 1957, unmanned Sputnik 1 satellite was launched by Russian R-7 rocket, reaching Earth orbit at 215-939 kilometers (134-583Ã, mi). This was followed by the first human spaceflight in 1961, when Yuri Gagarin was sent into orbit on Vostok 1. The first man to flee from Earth's orbit was Frank Borman, Jim Lovell and William Anders in 1968 on board the US Apollo 8, which reached the lunar. orbiting and reaching a maximum distance of 377,349 km (234,474 mi) of Earth.
The first spacecraft to reach escape speed was Soviet Luna 1, which did fly-by of the Moon in 1959. In 1961, Venera 1 became the first planetary probe. It reveals the presence of solar wind and performs a fly-by Venus, even though contact is lost before it reaches Venus. The first successful planet mission was the 1962 flying-by Venus by Mariner 2. The first fly by Mars was by Mariner 4 in 1964. Since then, unmanned spacecraft have managed to examine each of the planets of the Solar System, as well as their moons and many smaller planets and comets. They remain a fundamental tool for space exploration, as well as Earth observations. In August 2012, Voyager 1 became the first man-made object to leave the Solar System and enter the interstellar space.
The absence of air makes the outer space an ideal location for astronomy in all wavelengths of the electromagnetic spectrum. This is evidenced by the spectacular images being sent back by the Hubble Space Telescope, allowing light from over 13 billion years ago - almost to the time of Big Bang - to be observed. However, not every location is in an ideal space for telescopes. The inter-planetary zodiac dust emits diffuse near-infrared radiation that can mask the emission of a faint source like an extrasolar planet. Moving the infrared telescope through the dust increases its effectiveness. Similarly, sites such as the Daedalus crater on the far side of the Moon can protect the radio telescope from radio frequency interference that obstructs Earth-based observations.
Unmanned spacecraft in Earth orbit is an important technology of modern civilization. They allow direct monitoring of weather conditions, delivering long distance communications such as television, providing the right navigation means, and allowing remote sensing of the Earth. The last role serves a variety of purposes, including tracking soil moisture for agriculture, predicting the flow of water from seasonal snow packages, detection of diseases in plants and trees, and monitoring of military activity.
Deep space vacuum can make it an attractive environment for specific industrial processes, such as those requiring ultraclean surfaces. However, like asteroid mining, space manufacturing requires significant investment with few immediate return prospects. An important factor in total cost is the high cost of putting the mass into Earth orbit: $ 7,000-24,000 per kg in dollars adjusted for inflation, according to estimates for 2006. Proposed concepts to address this problem include the launch of non-rocket rockets, exchange of momentum exchanges, and the space elevator.
The interstellar journey for the human crew remains at this moment only a theoretical possibility. The distance to the nearest stars will require new technological developments and the ability to safely support crews for a trip that lasts decades. For example, the Daedalus Project study, which proposes a spacecraft supported by the fusion of Deuterium and Dia 3 , will take 36 years to reach the nearby Alpha Centauri system. Other proposed interstellar propulsion systems include light screens, ramjet, and light-powered propulsion. More advanced propulsion systems may use antimatter as a fuel, potentially achieving relativistic speed.
See also
References
Bibliography
External links
- Newscientist Space
- space.com
Source of the article : Wikipedia
0 Comments