611 articles
Timeline of Solar System exploration
A timeline of Solar System exploration by spacecraft, beginning with Mariner 2's first flyby of Venus in 1962 and covering landmark missions from Viking's Mars landing to New Horizons at Pluto.
Tisserand parameter
The Tisserand parameter, or Tisserand invariant, is a dimensionless orbital quantity, introduced by Félix Tisserand in 1896, that stays nearly constant when a comet passes close to a planet.
Titan (moon)
Titan is Saturn's largest moon and the second largest in the solar system, the only moon with a dense atmosphere, with liquid methane and ethane seas on its surface.
Titius–Bode law
The Titius–Bode law, also known as Bode's law, is an empirical rule giving the orbital distances of Solar System planets, stated by Titius in 1766 and popularized by Bode in 1772.
Toharu (crater on Ceres)
Toharu is an 86-km-diameter impact crater on the dwarf planet Ceres at 48.32°S, 155.95°E, named for a Pawnee god, with a central peak cut by a pit indicating subsurface ice.
TOI-1338 b
TOI-1338 b, also known as BEBOP-1b, is a circumbinary planet orbiting two stars in the constellation Pictor about 1,300 light-years away, the first discovered by NASA's TESS in 2020.
Torino scale
The Torino scale, or Torino Impact Hazard Scale, rates the hazard of asteroid and comet impacts with Earth on an integer scale from 0 to 10.
Total penumbral lunar eclipse
A total penumbral lunar eclipse is a lunar eclipse in which the Moon passes entirely through Earth's penumbra without entering the dark umbra, making it very faint.
Transit of Mercury
A transit of Mercury is Mercury's passage across the Sun's disk as seen from Earth, an event that happens about 13 times per century, first observed in 1631.
Transit of Venus
A transit of Venus, or transit of planet Venus, is the passage of Venus across the Sun's face as seen from Earth, occurring in pairs eight years apart.
Transition region (Sun)
The transition region is a thin layer of the Sun's atmosphere separating the hot corona from the cooler chromosphere, where the temperature drops from about 1,000,000°C to 20,000°C.
Transition Region and Coronal Explorer
The Transition Region and Coronal Explorer (TRACE) was a NASA Small Explorer satellite that imaged the Sun's transition region and corona in ultraviolet light from 1998 to 2010.
Transits and occultations observed from small Solar System bodies
Transits and occultations observed from small Solar System bodies: stellar occultations measure sizes and rings of Chariklo and Chiron, while Phobos gives Mars frequent partial eclipses.
Transits of Mercury from Venus
Transits of Mercury from Venus occur when Mercury passes between the Sun and Venus, appearing as a small dark disk; the next is on 16 January 2028.
Trinculo (moon)
Trinculo, formally Uranus XXI, is a small, dark irregular moon of Uranus in a retrograde orbit, about 11 miles (18 km) wide, discovered in 2001.
Triton (moon)
Triton, designated Neptune I, is the largest moon of Neptune, discovered by William Lassell in 1846. It orbits retrograde and is a candidate ocean world.
Trojan (celestial body)
A Trojan, or Trojan asteroid, is a small body sharing a planet's orbit and librating around the stable L4 or L5 Lagrange point, 60 degrees ahead of or behind.
Trojan configuration
A Trojan configuration is an orbital arrangement in which small bodies share a planet's orbit, oscillating around the stable L4 or L5 Lagrange point 60 degrees ahead or behind.
Uhola Catenae
Uhola Catenae: chains of troughs and elongated pits on dwarf planet Ceres, north of the Yalode basin; IAU-named 2016 after a Nigerian harvest festival; 400 km across, partly radial to Yalode.
Umbra, penumbra and antumbra
The umbra, penumbra, and antumbra are the three regions of a shadow cast by an opaque object in front of an extended light source such as the Sun.
Umbriel
Umbriel (Uranus II) is the third largest and darkest of Uranus's five classical moons, a heavily cratered icy body about 1,200 km wide, discovered by William Lassell in 1851.
Uottakh-sulus Valles
Uottakh-sulus Valles, a 1,100-km lava channel system (valles) on Venus at 12.5N, 239.0E, IAU-approved 1997; named with the Yakutian/Saha word for the planet Venus.
Uranus
Uranus is the seventh planet from the Sun, an ice giant tipped on its side, discovered by William Herschel in 1781 and visited once by Voyager 2 in 1986.
Ursids
The Ursids are an annual meteor shower radiating from Ursa Minor, peaking around December 22 with low rates most years but known outbursts, produced by comet 8P/Tuttle.
Venus
Venus, also called Sol II, is the second planet from the Sun, an Earth-sized world heated to 464 °C by a carbon-dioxide atmosphere 92 times heavier than Earth's.
Visibility of lunar eclipses by region
Visibility of lunar eclipses by region covers why about half the planet can see each lunar eclipse, and how altitude, timing, and location change the view.
Volcanism on Io
Volcanism on Io is the volcanic activity of Jupiter's moon Io, the most volcanically active body in the solar system, powered by tidal heating with about 400 volcanoes.
Voyager program
The Voyager program, also called the Voyager mission, is a NASA effort with two spacecraft, Voyager 1 and Voyager 2, launched in 1977 to tour the outer planets and now operating as interstellar probes.
Vulcan (hypothetical planet)
Vulcan, also called Planet Vulcan, was a hypothetical planet proposed by Le Verrier in the 19th century to explain Mercury's orbit, never found; Einstein explained the anomaly in 1915.
WASP-12b
WASP-12b is a hot Jupiter exoplanet discovered in 2008 by SuperWASP, orbiting its late-F star every 1.09 days at 0.0234 AU. It is inflated, tidally stripped, carbon-debate famous, and the only hot Jupiter with a confirmed decaying orbit.