300 articles
2015 BZ509
2015 BZ509, asteroid 514107, named Ka'epaoka'awela, is a small Solar System body about 3 km across, the first found in a stable retrograde co-orbital resonance with Jupiter.
2015 TG387
2015 TG387, nicknamed the Goblin, is a distant trans-Neptunian object discovered in 2015, with its extreme orbit fitting patterns attributed to the hypothetical Planet Nine.
2018 LA
2018 LA was a small asteroid discovered in space on 2 June 2018 that impacted Earth's atmosphere over Botswana about eight hours later, producing the Motopi Pan meteorites.
2020 CD3
2020 CD3 was a small near-Earth asteroid that became Earth's second known temporary natural satellite, or minimoon, discovered in February 2020 by the Catalina Sky Survey in Arizona.
Adrastea (moon)
Adrastea, also designated Jupiter XV, is the smallest of Jupiter's four small inner moons, discovered in Voyager images from 1979 and a principal source of the planet's main ring.
Ahuna Mons
Ahuna Mons is a 4-km-high mountain near the equator of the dwarf planet Ceres, the tallest there, formed as a cryovolcano that erupted salty, muddy brine.
Alfvén surface
The Alfvén surface is the boundary around a magnetized star where the solar wind outruns the Alfvén speed, first crossed by Parker Solar Probe in 2021.
Allende meteorite
The Allende meteorite, a carbonaceous chondrite (CV3), fell near Pueblito de Allende, Chihuahua, Mexico, in 1969; its calcium-aluminum-rich inclusions are the Solar System's oldest dated solids.
Amalthea (moon)
Amalthea is the largest of Jupiter's small inner moons, a dark red body about 270 km long that orbits closer to Jupiter than Io. It was discovered in 1892.
Ananke (moon)
Ananke, also designated Jupiter XII, is a small retrograde irregular moon of Jupiter discovered in 1951, and the largest member of the Ananke group of satellites.
Arche
Arche (Jupiter XLIII, S/2002 J1) is a ~1.5 km retrograde irregular moon of Jupiter in the Carme group, discovered in 2002 by Scott S. Sheppard, orbiting 23.4 million km out in 732 days.
Asteroid belt
The asteroid belt, also called the main asteroid belt, is a torus-shaped region between the orbits of Mars and Jupiter where most known asteroids orbit the Sun.
Asteroid impact avoidance
Asteroid impact avoidance, also known as asteroid deflection or planetary defense, aims to prevent dangerous near-Earth objects from hitting Earth, demonstrated by NASA's DART mission in 2022.
Asteroid impact prediction
Asteroid impact prediction is the process of computing near-Earth object orbits and estimating collision probabilities with Earth, carried out continuously by NASA's Sentry and ESA's Aegis monitoring systems.
Asteroid mining
Asteroid mining is the proposed extraction of water, metals, and other materials from asteroids, targeted chiefly at water for rocket propellant; no commercial extraction has taken place yet.
Asteroid spectral types
Asteroid spectral types are classes assigned from an asteroid's reflectance spectrum, whose shape indicates surface minerals; several taxonomies exist, with the Bus–DeMeo system of 25 classes most widely used.
Asteroid Terrestrial-impact Last Alert System
The Asteroid Terrestrial-impact Last Alert System (ATLAS) is a NASA-funded network of robotic telescopes in Hawaii, Chile, and South Africa that scans the sky nightly for incoming asteroids.
Astronomical naming conventions
Astronomical naming conventions, or astronomical nomenclature, are the rules by which stars, planets, minor planets, and comets receive designations and proper names, standardized since 1919 by the International Astronomical Union.
Atmosphere of Jupiter
The atmosphere of Jupiter (Jovian atmosphere) is an enormous envelope of hydrogen and helium with belts, zones, and the centuries-old Great Red Spot, twice as wide as Earth.
Atmosphere of Mars
The atmosphere of Mars, also called the Martian atmosphere, is a thin, carbon dioxide-dominated envelope of gas; its surface pressure is under one hundredth of Earth's sea-level pressure.
Atmosphere of Mercury
Mercury's atmosphere is a thin surface-bounded exosphere, the only planet without a substantial atmosphere, made of atoms blasted off its surface by solar wind and meteoroids.
Atmosphere of Neptune
Neptune's atmosphere, mostly hydrogen and helium with methane, is the most active of the giant planets, with winds up to 1,200 mph and storms like the Great Dark Spot.
Atmosphere of Titan
The atmosphere of Titan is a dense envelope of nitrogen and methane surrounding Saturn's largest moon, the only moon in the solar system with a substantial atmosphere.
Atmosphere of Venus
The atmosphere of Venus is a dense carbon dioxide envelope with 92 bars of surface pressure and a 467 °C surface kept hot by a runaway greenhouse effect.
Ayló'chaxnim
Ayló'chaxnim is a red, roughly 2-kilometer asteroid, the first ever found orbiting entirely inside Venus's orbit, discovered by the Zwicky Transient Facility at Palomar Observatory on 2020 January 4.
Bond albedo
The Bond albedo, also called the spherical albedo, is the fraction of total incoming radiation, at all wavelengths and angles, that a body reflects back into space.
Bright spots on Ceres
The bright spots on Ceres are unusually reflective deposits, called faculae, made mostly of sodium carbonate left by evaporating salty brine, first seen by Hubble in 2004.
Butterfly diagram
The butterfly diagram is a time–latitude plot of sunspots, first drawn by Edward Maunder in 1904, showing spots migrate from mid-latitudes toward the equator over each solar cycle.
C Ring
The C Ring is the innermost of Saturn's main rings, discovered in 1850, lying between the D and B Rings and known for bright plateaus found nowhere else.
C-type asteroid
A C-type asteroid, also called a carbonaceous asteroid, is a dark, carbon-rich asteroid whose spectrum resembles carbonaceous chondrite meteorites; C-types form the largest asteroid class, dominating the outer main belt.