(commonly abbreviated as ‘space’)
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*”outer space” is the ‘void’ that ‘exists’ between ‘celestial bodies’*
(including ‘earth’)
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(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’, ‘neutrinos’, ‘dust’, and ‘cosmic rays’)
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(the baseline temperature, as set by the background radiation from the ‘Big Bang’, is 2.7 kelvins (K) (−270.45 °C; −454.81 °F))
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(‘plasma’ with a number density of less than “1 hydrogen atom per cubic metre” and a temperature of “millions of kelvins” in the space between galaxies accounts for most of the ‘baryonic’ (aka ‘ordinary’) matter in ‘outer space’; local concentrations have condensed into ‘stars’ and ‘galaxies’)
(in most ‘galaxies’, observations provide evidence that 90% of the mass is in an unknown form, called ‘dark matter’, which interacts with other matter through ‘gravitational’ but not ‘electromagnetic’ forces)
(data indicates that the majority of the ‘mass-energy’ in the ‘observable universe’ is a poorly understood ‘vacuum energy’ of ‘space’ which astronomers label ‘dark energy’)
(‘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 ‘outer space’ starts)
(however the ‘kármán line’, at an altitude of 100 km (62 mi) above sea level, is conventionally used as the start of ‘outer space’ in ‘space treaties’ and for ‘aerospace records keeping’)
(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 the drafting of UN resolutions for the peaceful uses of ‘outer space’, ‘anti-satellite weapons’ have been tested in ‘earth orbit’)
(humans began the physical exploration of ‘space’ during the 20th century with the advent of ‘high-altitude balloon flights’, followed by ‘manned rocket launches’)
(‘earth orbit was first achieved by ‘Yuri Gagarin’ of the ‘Soviet Union’ in 1961 and ‘unmanned spacecraft’ have since reached all of the known planets in the ‘Solar System’)
(due to the high cost of getting into space, manned spaceflight has been limited to ‘low earth orbit’ and ‘the moon’)
(‘outer space’ represents a challenging environment for ‘human exploration’ because of the dual hazards of ‘vacuum’ and ‘radiation’)
(‘microgravity’ also has a negative effect on ‘human physiology’ that causes both ‘muscle atrophy’ and ‘bone loss’)
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(in addition to these health and environmental issues, the economic cost of putting ‘objects’, including ‘humans’, into ‘space’ is very high)
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*👨🔬🕵️♀️🙇♀️*SKETCHES*🙇♂️👩🔬🕵️♂️*
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👈👈👈☜*“EARTH ATMOSPHERIC SUB-DIVISIONS”* ☞ 👉👉👉
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💕💝💖💓🖤💙🖤💙🖤💙🖤❤️💚💛🧡❣️💞💔💘❣️🧡💛💚❤️🖤💜🖤💙🖤💙🖤💗💖💝💘
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*🌈✨ *TABLE OF CONTENTS* ✨🌷*
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🔥🔥🔥🔥🔥🔥*we won the war* 🔥🔥🔥🔥🔥🔥