54 relations: Angular momentum, Apparent retrograde motion, Asteroid, Astronomical object, Astronomy, Ceres (dwarf planet), Chaos theory, Charon (moon), Differential rotation, Earth, Ecliptic, Ephemeris, Ephemeris time, Equinox, Fixed stars, Gas giant, Gravity, Haumea, Hyperion (moon), International Earth Rotation and Reference Systems Service, International System of Units, Jupiter, List of fast rotators (minor planets), List of slow rotators (minor planets), Magnetic field, Mars, Mercury (planet), Moment of inertia, Moon, Neptune, Newcomb's Tables of the Sun, Orbital period, Planet, Pluto, Poles of astronomical bodies, Precession, Retrograde and prograde motion, Rotation around a fixed axis, Rotational speed, Saturn, Second, Sidereal time, Simon Newcomb, Solar rotation, Sphere, Star, Sun, Symmetry, Synodic day, Tidal acceleration, ..., Tidal force, Tidal locking, Uranus, Venus. Expand index (4 more) » « Shrink index
In physics, angular momentum (rarely, moment of momentum or rotational momentum) is the rotational equivalent of linear momentum.
Apparent retrograde motion is the apparent motion of a planet in a direction opposite to that of other bodies within its system, as observed from a particular vantage point.
Asteroids are minor planets, especially those of the inner Solar System.
An astronomical object or celestial object is a naturally occurring physical entity, association, or structure that exists in the observable universe.
Astronomy (from ἀστρονομία) is a natural science that studies celestial objects and phenomena.
Ceres (minor-planet designation: 1 Ceres) is the largest object in the asteroid belt that lies between the orbits of Mars and Jupiter, slightly closer to Mars' orbit.
Chaos theory is a branch of mathematics focusing on the behavior of dynamical systems that are highly sensitive to initial conditions.
Charon, also known as (134340) Pluto I, is the largest of the five known natural satellites of the dwarf planet Pluto.
Differential rotation is seen when different parts of a rotating object move with different angular velocities (rates of rotation) at different latitudes and/or depths of the body and/or in time.
Earth is the third planet from the Sun and the only astronomical object known to harbor life.
The ecliptic is the circular path on the celestial sphere that the Sun follows over the course of a year; it is the basis of the ecliptic coordinate system.
In astronomy and celestial navigation, an ephemeris (plural: ephemerides) gives the positions of naturally occurring astronomical objects as well as artificial satellites in the sky at a given time or times.
The term ephemeris time (often abbreviated ET) can in principle refer to time in connection with any astronomical ephemeris.
An equinox is commonly regarded as the moment the plane (extended indefinitely in all directions) of Earth's equator passes through the center of the Sun, which occurs twice each year, around 20 March and 22-23 September.
The fixed stars (stellae fixae) comprise the background of astronomical objects that appear to not move relative to each other in the night sky compared to the foreground of Solar System objects that do.
A gas giant is a giant planet composed mainly of hydrogen and helium.
Gravity, or gravitation, is a natural phenomenon by which all things with mass or energy—including planets, stars, galaxies, and even light—are brought toward (or gravitate toward) one another.
Haumea, minor-planet designation 136108 Haumea, is a dwarf planet located beyond Neptune's orbit.
Hyperion (Greek: Ὑπερίων), also known as Saturn VII (7), is a moon of Saturn discovered by William Cranch Bond, George Phillips Bond and William Lassell in 1848.
The International Earth Rotation and Reference Systems Service (IERS), formerly the International Earth Rotation Service, is the body responsible for maintaining global time and reference frame standards, notably through its Earth Orientation Parameter (EOP) and International Celestial Reference System (ICRS) groups.
The International System of Units (SI, abbreviated from the French Système international (d'unités)) is the modern form of the metric system, and is the most widely used system of measurement.
Jupiter is the fifth planet from the Sun and the largest in the Solar System.
This is a list of fast rotators—minor planets that have an exceptionally short rotation period, also called "rotation rate" or "spin rate".
This is a list of slow rotators—minor planets that have an exceptionally long rotation period.
A magnetic field is a vector field that describes the magnetic influence of electrical currents and magnetized materials.
Mars is the fourth planet from the Sun and the second-smallest planet in the Solar System after Mercury.
Mercury is the smallest and innermost planet in the Solar System.
The moment of inertia, otherwise known as the angular mass or rotational inertia, of a rigid body is a tensor that determines the torque needed for a desired angular acceleration about a rotational axis; similar to how mass determines the force needed for a desired acceleration.
The Moon is an astronomical body that orbits planet Earth and is Earth's only permanent natural satellite.
Neptune is the eighth and farthest known planet from the Sun in the Solar System.
Newcomb's Tables of the Sun is the short title and running head of a work by the American astronomer and mathematician Simon Newcomb entitled "Tables of the Motion of the Earth on its Axis and Around the Sun" on pages 1–169 of "Tables of the Four Inner Planets" (1895), volume VI of the serial publication Astronomical Papers Prepared for the Use of the American Ephemeris and Nautical Almanac.
The orbital period is the time a given astronomical object takes to complete one orbit around another object, and applies in astronomy usually to planets or asteroids orbiting the Sun, moons orbiting planets, exoplanets orbiting other stars, or binary stars.
A planet is an astronomical body orbiting a star or stellar remnant that is massive enough to be rounded by its own gravity, is not massive enough to cause thermonuclear fusion, and has cleared its neighbouring region of planetesimals.
Pluto (minor planet designation: 134340 Pluto) is a dwarf planet in the Kuiper belt, a ring of bodies beyond Neptune.
The poles of astronomical bodies are determined based on their axis of rotation in relation to the celestial poles of the celestial sphere.
Precession is a change in the orientation of the rotational axis of a rotating body.
Retrograde motion in astronomy is, in general, orbital or rotational motion of an object in the direction opposite the rotation of its primary, that is the central object (right figure).
Rotation around a fixed axis or about a fixed axis of revolution or motion with respect to a fixed axis of rotation is a special case of rotational motion.
Rotational speed (or speed of revolution) of an object rotating around an axis is the number of turns of the object divided by time, specified as revolutions per minute (rpm), cycles per second (cps), radians per second (rad/s), etc..
Saturn is the sixth planet from the Sun and the second-largest in the Solar System, after Jupiter.
The second is the SI base unit of time, commonly understood and historically defined as 1/86,400 of a day – this factor derived from the division of the day first into 24 hours, then to 60 minutes and finally to 60 seconds each.
Sidereal time is a timekeeping system that astronomers use to locate celestial objects.
Simon Newcomb (March 12, 1835 – July 11, 1909) was a Canadian–American astronomer, applied mathematician and autodidactic polymath, who was Professor of Mathematics in the U.S. Navy and at Johns Hopkins.
Solar rotation varies with latitude because the Sun is composed of a gaseous plasma.
A sphere (from Greek σφαῖρα — sphaira, "globe, ball") is a perfectly round geometrical object in three-dimensional space that is the surface of a completely round ball (viz., analogous to the circular objects in two dimensions, where a "circle" circumscribes its "disk").
A star is type of astronomical object consisting of a luminous spheroid of plasma held together by its own gravity.
The Sun is the star at the center of the Solar System.
Symmetry (from Greek συμμετρία symmetria "agreement in dimensions, due proportion, arrangement") in everyday language refers to a sense of harmonious and beautiful proportion and balance.
A synodic day is the period it takes for a planet to rotate once in relation to the body it is orbiting.
Tidal acceleration is an effect of the tidal forces between an orbiting natural satellite (e.g. the Moon), and the primary planet that it orbits (e.g. Earth).
The tidal force is an apparent force that stretches a body towards the center of mass of another body due to a gradient (difference in strength) in gravitational field from the other body; it is responsible for the diverse phenomena, including tides, tidal locking, breaking apart of celestial bodies and formation of ring systems within Roche limit, and in extreme cases, spaghettification of objects.
Tidal locking (also called gravitational locking or captured rotation) occurs when the long-term interaction between a pair of co-orbiting astronomical bodies drives the rotation rate of at least one of them into the state where there is no more net transfer of angular momentum between this body (e.g. a planet) and its orbit around the second body (e.g. a star); this condition of "no net transfer" must be satisfied over the course of one orbit around the second body.
Uranus is the seventh planet from the Sun.
Venus is the second planet from the Sun, orbiting it every 224.7 Earth days.