Outer space, or simply space, is the void that exists between celestial bodies, including the Earth. It is not completely empty, but consists of a hard vacuum containing a low density of particles: predominantly a plasma of hydrogen and helium, as well as electromagnetic radiation, magnetic fields, and neutrinos. Observations and theory suggest that it also contains dark matter and dark energy. The baseline temperature, as set by the background radiation left over from the Big Bang, is only 2.7 Kelvin (K); in contrast, temperatures in the coronae of stars can reach over a million Kelvin. Plasma with an extremely low density (less than one hydrogen atom per cubic meter) and high temperature (millions of Kelvin) in the space between galaxies accounts for most of the baryonic (ordinary) matter in outer space; local concentrations have condensed into stars and galaxies. Intergalactic space takes up most of the volume of the Universe, but even galaxies and star systems consist almost entirely of empty space.
There is no firm boundary where space begins. However the Kármán line, at an altitude of 100 km (62 mi) above sea level, is conventionally used as the start of outer space for the purpose of space treaties and aerospace records keeping. The framework for international space law was established by the Outer Space Treaty, which was passed by the United Nations in 1967. This treaty precludes any claims of national sovereignty and permits all states to explore outer space freely. In 1979, the Moon Treaty made the surfaces of objects such as planets, as well as the orbital space around these bodies, the jurisdiction of the international community. Additional resolutions regarding the peaceful uses of outer space have been drafted by the United Nations, but these have not precluded the deployment of weapons into outer space, including the live testing of anti-satellite weapons.
Humans began the physical exploration of space during the 20th century with the advent of high-altitude balloon flights, followed by the development of single and multi-stage rocket launchers. Earth orbit was achieved by Yuri Gagarin in 1961 and unmanned spacecraft have since reached all of the known planets in the Solar System. Achieving orbit requires a minimum velocity of 28,400 km/h (17,600 mph); much faster than any conventional aircraft. Outer space represents a challenging environment for human exploration because of the dual hazards of vacuum and radiation. Microgravity has a deleterious effect on human physiology, resulting in muscle atrophy and bone loss. As of yet space travel has been limited to low Earth orbit and the Moon for manned flight, and the vicinity of the solar system for unmanned; the remainder of outer space remains inaccessible to humans other than by passive observation with telescopes.
Other articles related to "outer space, space, outer":
... Nazo no Kyōryū Kichi?) The Rascal from Outer Space (Alternate DVD Title The Ruffian From Outer Space/The Rambunctious One From Space) (宇宙から来た暴れん坊, Uchū kara Kita ... Cosmic Rays (Alternate DVD Title The Space Ray of Terror) (恐怖の宇宙線, Kyōfu no Uchūsen?) Science Patrol Into Space (Alternate DVD Title The Science Patrol in Outer ...
... Smith wrote mainly about outer space, with such works as Operation Interstellar (1950), Lost in Space (1959), and Troubled Star (1957) ... chiefly for his Venus Equilateral series of short stories about a communications station in outer space ... as The Brain Machine (1968) - was a digression from his focus on outer space, and provides one of the more interesting examinations of a child prodigy in science fiction ...
... War paranoia, public fascination with Outer Space, and a renewed interest in science sparked by the atom bomb lent itself well to science fiction films ... Stood Still, Invaders from Mars, Them!, The War of the Worlds, The Time Machine, It Came from Outer Space, The Beast from 20,000 Fathoms, Creature from the Black Lagoon, The Thing from ... Queen of Outer Space (1958) with Zsa Zsa Gabor brought sex to the genre ...
... For the majority of human history, space was explored by remote observation initially with the unaided eye and then with the telescope ... to the advent of reliable rocket technology, the closest that humans had come to reaching outer space was through the use of balloon flights ... They remain a fundamental tool for the exploration of outer space, as well as observation of the Earth ...
Famous quotes related to outer space:
“Gillian Taylor: Youre from outer space?
James T. Kirk: No, Im from Iowa; I work in outer space.”
—Harve Bennett (b. 1930)
“Just like those other black holes from outer space, Hollywood is postmodern to this extent: it has no center, only a spreading dead zone of exhaustion, inertia, and brilliant decay.”
—Arthur Kroker (b. 1945)
“Dont you see whats at stake here? The ultimate aim of all scienceto penetrate the unknown. Do you realize we know less about the earth we live on than about the stars and the galaxies of outer space? The greatest mystery is right here, right under our feet.”
—Walter Reisch (19031963)
“At the rate science proceeds, rockets and missiles will one day seem like buffaloslow, endangered grazers in the black pasture of outer space.”
—Bernard Cooper (b. 1936)
“After one look at this planet any visitor from outer space would say I WANT TO SEE THE MANAGER.”
—William Burroughs (b. 1914)