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A solar eclipse occurs when the Moon passes between Earth and the Sun, thereby obscuring the view of the Sun from a small part of Earth, totally or partially...

In astronomy, stellar classification is the classification of stars based on their spectral characteristics. Electromagnetic radiation from the star is...

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...

A lunar eclipse is an astronomical event that occurs when the Moon moves into the Earth's shadow, causing the Moon to be darkened. Such an alignment occurs...

The European Space Agency (ESA) is a 22-member intergovernmental body devoted to space exploration. With its headquarters in Paris and a staff of around...

Space Shuttle Columbia (OV-102) was a Space Shuttle orbiter manufactured by Rockwell International and operated by NASA. Named after the first American...

A neutron star is a collapsed core of a massive supergiant star. The stars that later collapse into neutron stars have a total mass of between 10 and 25...

Alpha Centauri (α Centauri, α Cen, or Alpha Cen) is a triple star system in the southern constellation of Centaurus. It consists of three stars: Rigil...

A binary star or binary star system is a system of two stars that are gravitationally bound to and in orbit around each other. Binary stars in the night...

Apparent magnitude (m) is a measure of the brightness of a star or other astronomical object to an observer on Earth. An object's apparent magnitude depends...

An atmosphere (from Ancient Greek ἀτμός (atmós) 'vapour, steam', and σφαῖρα (sphaîra) 'sphere') is a layer of gasses that envelop an astronomical object...

New Horizons is an interplanetary space probe launched as a part of NASA's New Frontiers program. Engineered by the Johns Hopkins University Applied Physics...

Cassini–Huygens (/kəˈsiːni ˈhɔɪɡənz/ kə-SEE-nee HOY-gənz), commonly called Cassini, was a space-research mission by NASA, the European Space Agency (ESA)...

A natural satellite is, in the most common usage, an astronomical body that orbits a planet, dwarf planet, or small Solar System body (or sometimes another...

A spacecraft is a vehicle that is designed to fly in outer space and operate there. Spacecraft are used for a variety of purposes, including communications...

Brown dwarfs are substellar objects that have more mass than the biggest gas giant planets, but less than the least massive main-sequence stars. Their...

99942 Apophis (provisional designation 2004 MN4) is a near-Earth asteroid and a potentially hazardous object with a diameter of 370 metres (1,210 feet)...

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

Luminosity is an absolute measure of radiated electromagnetic energy (light) per unit time, and is synonymous with the radiant power emitted by a light-emitting...

Right ascension (abbreviated RA; symbol α) is the angular distance of a particular point measured eastward along the celestial equator from the Sun at...