Subscribe to America's largest dictionary and get thousands more definitions and advanced search—ad free! There is no clear boundary between Earth's atmosphere and space, as the density of the atmosphere gradually decreases as the altitude increases. The treaty has not been ratified by any nation that currently practices human spaceflight. Outer space is not completely empty—it is a hard vacuum containing a low density of particles, predominantly a plasma of hydrogen and helium, as well as electromagnetic radiation, magnetic fields, neutrinos, dust, and cosmic rays. Studies of the large scale distribution of galaxies show that the Universe has a foam-like structure, with groups and clusters of galaxies lying along filaments that occupy about a tenth of the total space. , When stars are moving at sufficiently high peculiar velocities, their astrospheres can generate bow shocks as they collide with the interstellar medium. It has effectively no friction, allowing stars, planets, and moons to move freely along their ideal orbits, following the initial formation stage.  This theory holds that the universe originated from a very dense form that has since undergone continuous expansion. Please tell us where you read or heard it (including the quote, if possible). At or above the Armstrong line, fluids in the throat and lungs boil away. 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. The duration of space sickness varies, but it typically lasts for 1–3 days, after which the body adjusts to the new environment. 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 altitude where atmospheric pressure matches the vapor pressure of water at the temperature of the human body is called the Armstrong line, named after American physician Harry G. Armstrong.  Interplanetary space extends out to the heliopause where the influence of the galactic environment starts to dominate over the magnetic field and particle flux from the Sun. Noun. The idea of the luminiferous aether was then abandoned.  But the scale of the Universe remained unknown until the first successful measurement of the distance to a nearby star in 1838 by the German astronomer Friedrich Bessel.  In 1961, Venera 1 became the first planetary probe. (There is quite likely a correspondingly large number of neutrinos called the cosmic neutrino background.  Swelling and ebullism can be reduced by containment in a pressure suit. More specifically, exposed bodily liquids such as saliva, tears, and liquids in the lungs boil away. Instead, these authors argue that a subsonic bow wave defines the transition from the solar wind flow to the interstellar medium.  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). (Although the plasma is very hot by terrestrial standards, 105 K is often called "warm" in astrophysics.)  The flat Universe, combined with the measured mass density of the Universe and the accelerating expansion of the Universe, indicates that space has a non-zero vacuum energy, which is called dark energy.  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. outer space Outer space is the area outside the earth's atmosphere where the other planets and stars are situated.  The cost of access to space has declined since 2013. 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. Despite the drafting of UN resolutions for the peaceful uses of outer space, anti-satellite weapons have been tested in Earth orbit. In the Western world, many people wear black to funerals to show mourning. outer space definition in English dictionary, outer space meaning, synonyms, see also 'on the outer',outer bar',outer garments',Outer Hebrides'.  Like asteroid mining, space manufacturing would require a large financial investment with little prospect of immediate return. See more. Cambridge Dictionary +Plus ‘The atmosphere is clearly not outer space, despite the difficulty of defining the boundaries of that area.’. Outer space definition: Outer space is the area outside the earth's atmosphere where the other planets and stars... | Meaning, pronunciation, translations and examples Moving an infrared telescope out past the dust increases its effectiveness.  Local concentrations of matter have condensed into stars and galaxies. The inner boundary is the ionosphere. , Interplanetary space contains the magnetic field generated by the Sun. , As a consequence of rapid decompression, oxygen dissolved in the blood empties into the lungs to try to equalize the partial pressure gradient. Further, space is a vacuum, meaning that sound cannot carry because molecules are not close enough together to transmit sound between them. At these temperatures, it is called the warm–hot intergalactic medium (WHIM). The term outward space was used in 1842 by the English poet Lady Emmeline Stuart-Wortley in her poem "The Maiden of Moscow". , Geospace is populated by electrically charged particles at very low densities, the motions of which are controlled by the Earth's magnetic field.  This material is called the intergalactic medium (IGM). n-uncount In 1957, the Soviets launched Sputnik 1 into outer space. Non-thermal radio sources have been detected even among the most distant, high-z sources, indicating the presence of magnetic fields. This name comes from the old English word ‘steorra,’ and is a different form of the name star.  The Van Allen radiation belts lie within the geospace. The remainder forms huge voids that are mostly empty of galaxies. Due to the high cost of getting into space, human spaceflight has been limited to low Earth orbit and the Moon.  The steam may bloat the body to twice its normal size and slow circulation, but tissues are elastic and porous enough to prevent rupture. 1. outer space - any location outside the Earth's atmosphere; "the astronauts walked in outer space without a tether"; "the first major milestone in space exploration was in 1957, when the USSR's Sputnik 1 orbited the Earth". The boundary represents the midpoint of a gradual transition over tens of kilometers from the relatively gentle winds of the Earth's atmosphere to the more violent flows of charged particles in space, which can reach speeds well over 268 m/s (600 mph).  The distance to the Andromeda Galaxy was determined in 1923 by American astronomer Edwin Hubble by measuring the brightness of cepheid variables in that galaxy, a new technique discovered by Henrietta Leavitt. Dec 21st, 2018 12:35am report. 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. Microgravity also has a negative effect on human physiology that causes both muscle atrophy and bone loss. According to the eulogy given by Kathryn Janeway to John Kelly, "Space. This form of aether was viewed as the medium through which light could propagate.  Magnetic storms can also be a hazard to astronauts, even in low Earth orbit. 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. , In 1650, German scientist Otto von Guericke constructed the first vacuum pump: a device that would further refute the principle of horror vacui. Range has large gradients of pressure, temperature and composition, and solar! 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