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A star is a luminous spheroid of plasma held together by self-gravity. The nearest star to Earth is the Sun. Many other stars are visible to the naked...

The Space Shuttle program was the fourth human spaceflight program carried out by the U.S. National Aeronautics and Space Administration (NASA), which...

There is evidence that the formation of the Solar System began about 4.6 billion years ago with the gravitational collapse of a small part of a giant molecular...

A star catalogue is an astronomical catalogue that lists stars. In astronomy, many stars are referred to simply by catalogue numbers. There are a great...

The Space Launch System (SLS) is an American super heavy-lift expendable launch vehicle used by NASA. As the primary launch vehicle of the Artemis Moon...

Space colonization is the use of outer space for colonization, such as permanent habitation, exploitation or territorial claims. Extraterrestrial colonization is...

The cosmic microwave background (CMB or CMBR) is microwave radiation that fills all space in the observable universe. It is a remnant that provides an...

Spacecraft propulsion is any method used to accelerate spacecraft and artificial satellites. In-space propulsion exclusively deals with propulsion systems...

Ophiuchus (/ˌɒfiˈjuːkəs/) is a large constellation straddling the celestial equator. Its name comes from the Ancient Greek ὀφιοῦχος (ophioûkhos), meaning...

Charon (/ˈkɛərɒn, -ən/ KAIR-on, -⁠ən or /ˈʃærən/ SHAIR-ən), or (134340) Pluto I, is the largest of the five known natural satellites of the dwarf planet...

Planetary habitability is the measure of a planet's or a natural satellite's potential to develop and maintain environments hospitable to life. Life may...

Heliocentrism (also known as the heliocentric model) is a superseded astronomical model in which the Earth and planets revolve around the Sun at the center...

The search for extraterrestrial intelligence (SETI) is a collective term for scientific searches for intelligent extraterrestrial life, for example, monitoring...

This is a list of stars arranged by their apparent magnitude – their brightness as observed from Earth. It includes all stars brighter than magnitude +2...

Proton (Russian: Протон) (formal designation: UR-500) is an expendable launch system used for both commercial and Russian government space launches. The...

A small satellite, miniaturized satellite, or smallsat is a satellite of low mass and size, usually under 1,200 kg (2,600 lb). While all such satellites...

During the late 19th and early 20th centuries, it was erroneously believed that there were "canals" on the planet Mars. These were a network of long straight...

In astrophysics, accretion is the accumulation of particles into a massive object by gravitationally attracting more matter, typically gaseous matter,...

The Hill sphere is a common model for the calculation of a gravitational sphere of influence. It is the most commonly used model to calculate the spatial...

Amateur astronomy is a hobby where participants enjoy observing or imaging celestial objects in the sky using the unaided eye, binoculars, or telescopes...