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Militarisation of space
The militarisation of space1 is the placement and development of weaponry in outer space by the militaries of the ... > more -
Space debris
Space debris or orbital debris, also called space junk and space waste, are the objects in orbit around Earth created by man that no longer serve any useful purpose. They consist of everything from ... > more -
Ionosphere
The ionosphere is the part of the atmosphere that is ionized by solar radiation. It plays an important part in atmospheric electricity and forms the inner edge of the magnetosphere. It has practical ... > more -
Near-Earth object
Near-Earth objects (NEO) are asteroids, comets and large meteoroids whose orbit intersects Earth's orbit and which may therefore pose a collision danger. Due to their size and proximity, NEOs are ... > more -
Outer space
Outer space, also simply called space, refers to the relatively empty regions of the universe outside the atmospheres of celestial bodies. Outer space is used to distinguish it from airspace (and ... > more -
Comet Hale-Bopp
Comet Hale-Bopp was probably the most widely observed comet of the 20th century, and one of the brightest seen for many decades. It was visible to the naked eye for a record 18 months, twice as long ... > more -
Extrasolar planet
An extrasolar planet, or exoplanet, is a planet beyond the Solar System. As of 11 November 2006, 209 extrasolar planets have been discovered. Known exoplanets are members of planetary systems that ... > more -
Red supergiant
Red supergiants are supergiant stars of spectral type K-M and a luminosity class of I. They are the largest stars in the universe in terms of physical size, although they are not the most massive. ... > more -
Comet Shoemaker-Levy 9
Comet Shoemaker-Levy 9 (SL9, formally designated D/1993 F2) was a comet which collided with Jupiter in 1994, providing the first direct observation of the collision of two solar system ... > more
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