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An apsis (from Ancient Greek ἁψίς (hapsís) 'arch, vault'; pl. apsides /ˈæpsɪˌdiːz/ AP-sih-deez) is the farthest or nearest point in the orbit of a planetary...

The astronomical unit (symbol: au, or AU) is a unit of length defined to be exactly equal to 149,597,870,700 m. Historically, the astronomical unit was...

The Antikythera mechanism (/ˌæntɪkɪˈθɪərə/ AN-tik-ih-THEER-ə, US also /ˌæntaɪkɪˈ-/ AN-ty-kih-) is an Ancient Greek hand-powered orrery (model of the Solar...

Mir (Russian: Мир, IPA: [ˈmʲir]; lit. 'peace' or 'world') was a space station that operated in low Earth orbit from 1986 to 2001, operated by the Soviet...

Space debris (also known as space junk, space pollution, space waste, space trash, space garbage, or cosmic debris) are defunct human-made objects in space –...

An eclipse is an astronomical event which occurs when an astronomical object or spacecraft is temporarily obscured, by passing into the shadow of another...

A minute of arc, arcminute (arcmin), arc minute, or minute arc, denoted by the symbol ′, is a unit of angular measurement equal to ⁠1/60⁠ of one degree...

The Japan Aerospace Exploration Agency (JAXA) (国立研究開発法人宇宙航空研究開発機構, Kokuritsu-kenkyū-kaihatsu-hōjin Uchū Kōkū Kenkyū Kaihatsu Kikō, lit. 'National Research...

This is a list of astronauts by year of selection: people selected to train for a human spaceflight program to command, pilot, or serve as a crew member...

The following list include some of the potentially habitable exoplanets discovered so far. It is mostly based on estimates of habitability by the Habitable...

Firefly Aerospace is an American private aerospace firm based in Cedar Park, Texas, that develops launch vehicles for commercial launches to orbit. The...

This article lists all active and upcoming orbital launch systems. For retired launch vehicles, see Comparison of retired orbital launch systems. This...

Medieval Islamic astronomy comprises the astronomical developments made in the Islamic world, particularly during the Islamic Golden Age (9th–13th centuries)...

This is a list of Arabic star names. In Western astronomy, most of the accepted star names are Arabic, a few are Greek and some are of unknown origin....

Hygiea (minor-planet designation: 10 Hygiea) is a major asteroid located in the main asteroid belt. With a mean diameter of between 425 and 440 km and...

Stardust was a 385-kilogram robotic space probe launched by NASA on 7 February 1999. Its primary mission was to collect dust samples from the coma of comet...

Space launch market competition is the manifestation of market forces in the launch service provider business. In particular it is the trend of competitive...

This is a chronological list of spaceflights to the International Space Station (ISS), including long-term ISS crew, short term visitors, replacement/rescue...

A Type II supernova or SNII (plural: supernovae) results from the rapid collapse and violent explosion of a massive star. A star must have at least eight...

NGC 40 (also known as the Bow-Tie Nebula and Caldwell 2) is a planetary nebula discovered by William Herschel on November 25, 1788, and is composed of...