Concept
Neptune
Related concepts (114)
Galatea (moon)
Galatea ɡæləˈtiːə, also known as Neptune VI, is the fourth-closest inner moon of Neptune. It is named after Galatea, one of the fifty Nereids of Greek legend, with whom Cyclops Polyphemus was vainly in love. Galatea was discovered in late July 1989 from the images taken by the Voyager 2 probe. It was given the temporary designation S/1989 N 4. The discovery was announced (IAUC 4824) on 2 August 1989, and mentions "10 frames taken over 5 days", implying a discovery date of sometime before July 28.
Synodic day
A synodic day (or synodic rotation period or solar day) is the period for a celestial object to rotate once in relation to the star it is orbiting, and is the basis of solar time. The synodic day is distinguished from the sidereal day, which is one complete rotation in relation to distant stars, which is the basis of sidereal time. This is different from the duration of a synodic day because the revolution of the body around its parent star would cause a single "day" to pass relative to a star, even if the body itself did not rotate.
Tidal locking
Tidal locking between a pair of co-orbiting astronomical bodies occurs when one of the objects reaches a state where there is no longer any net change in its rotation rate over the course of a complete orbit. In the case where a tidally locked body possesses synchronous rotation, the object takes just as long to rotate around its own axis as it does to revolve around its partner. For example, the same side of the Moon always faces the Earth, although there is some variability because the Moon's orbit is not perfectly circular.
Roche limit
In celestial mechanics, the Roche limit, also called Roche radius, is the distance from a celestial body within which a second celestial body, held together only by its own force of gravity, will disintegrate because the first body's tidal forces exceed the second body's self-gravitation. Inside the Roche limit, orbiting material disperses and forms rings, whereas outside the limit, material tends to coalesce. The Roche radius depends on the radius of the first body and on the ratio of the bodies' densities.
Dwarf planet
A dwarf planet is a small planetary-mass object that is in direct orbit of the Sun, smaller than any of the eight classical planets but still a world in its own right. The prototypical dwarf planet is Pluto. The interest of dwarf planets to planetary geologists is that they may be geologically active bodies, an expectation that was borne out in 2015 by the Dawn mission to and the New Horizons mission to Pluto. Astronomers are in general agreement that at least the nine largest candidates are dwarf planets: , , , , , , , , and .
Great Red Spot
The Great Red Spot is a persistent high-pressure region in the atmosphere of Jupiter, producing an anticyclonic storm that is the largest in the Solar System. It is the most recognizable feature on Jupiter, owing to its red-orange color whose origin is still unknown. Located 22 degrees south of Jupiter's equator, it produces wind-speeds up to 432 km/h (268 mph). Observations from 1665 to 1713 are believed to be of the same storm; if this is correct, it has existed for at least years.
Inner moon
In astronomy, an inner moon or inner natural satellite is a natural satellite following a prograde, low-inclination orbit inwards of the large satellites of the parent planet. They are generally thought to have been formed in situ at the same time as the coalescence of the original planet. Neptune's moons are an exception, as they are likely reaggregates of the pieces of the original bodies, which were disrupted after the capture of the large moon Triton.
Trojan (celestial body)
In astronomy, a trojan is a small celestial body (mostly asteroids) that shares the orbit of a larger body, remaining in a stable orbit approximately 60° ahead of or behind the main body near one of its Lagrangian points and . Trojans can share the orbits of planets or of large moons. Trojans are one type of co-orbital object. In this arrangement, a star and a planet orbit about their common barycenter, which is close to the center of the star because it is usually much more massive than the orbiting planet.
Planet symbols
A planet symbol or planetary symbol is a graphical symbol used in astrology and astronomy to represent a classical planet (including the Sun and the Moon) or one of the modern planets. The symbols were also used in alchemy to represent the metals associated with the planets, and in calendars for their associated days. The use of these symbols derives from Classical Greco-Roman astronomy, though their current shapes are a development of the 16th century.
Axial tilt
In astronomy, axial tilt, also known as obliquity, is the angle between an object's rotational axis and its orbital axis, which is the line perpendicular to its orbital plane; equivalently, it is the angle between its equatorial plane and orbital plane. It differs from orbital inclination. At an obliquity of 0 degrees, the two axes point in the same direction; that is, the rotational axis is perpendicular to the orbital plane.