The rotation period of an astronomical object is the time it takes to complete one revolution around its axis of rotation relative to the background stars. Astronomy (from the Greek words astron (ἄστρον "star" and nomos (νόμος "law" is the scientific study s are significant physical entities, associations or structures which current Science has confirmed to exist in Space. A rotation is a movement of an object in a circular motion A two- Dimensional object rotates around a center (or point) of rotation It differs from the planet's solar day, which includes an extra fractional rotation needed to accommodate the portion of the planet's orbital period during one day. Solar times are measures of the apparent position of the Sun on the Celestial sphere. The orbital period is the time taken for a given object to make one complete Orbit about another object Earth's rotation period differs from its sidereal day, which, despite its name, is not relative to the stars but is relative to the northward vernal equinox, which moves slowly across the celestial sphere. Sidereal time is a measure of the position of the Earth in its rotation around its axis or time measured by the apparent Diurnal motion of the Vernal equinox An equinox is the event of the Sun passing over the Earth's equator in its annual cycle In Astronomy and Navigation, the celestial sphere is an imaginary rotating Sphere of "gigantic Radius " The component of this precession along the celestial equator during one day, and hence the difference between Earth's rotation period and its sidereal day is 8. In Astronomy, Precession refers to the movement of the rotational axis of a body such as a planet with respect to Inertial space. The celestial equator is a Great circle on the imaginary Celestial sphere, in the same plane as the Earth 's Equator. 4 ms. [1]
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Measuring rotation
For solid objects, such as rocky planets and asteroids, the rotation period is a single value. A planet, as defined by the International Astronomical Union (IAU is a celestial body Orbiting a Star or stellar remnant that is Asteroids, sometimes called Minor planets or planetoids', are bodies—primarily of the inner Solar System —that are smaller than planets but For gaseous/fluid bodies, such as stars and gas giant planets, the period of rotation varies from the equator to the poles due to a phenomenon called differential rotation. A star is a massive luminous ball of plasma. The nearest star to Earth is the Sun, which is the source of most of the Energy on Earth A gas giant (sometimes also known as a Jovian planet after the planet Jupiter, or giant planet) is a large Planet that is not primarily Differential rotation is seen when different parts of a rotating object move with different angular velocities (rates of Rotation) Typically, the stated rotation period for a gas giant (Jupiter, Saturn, Uranus, Neptune) is its internal rotation period, as determined from the rotation of the planet's magnetic field. In Physics, a magnetic field is a Vector field that permeates space and which can exert a magnetic force on moving Electric charges For objects that are not spherically symmetrical, the rotation period is in general not fixed, even in the absence of gravitational or tidal forces. "Globose" redirects here See also Globose nucleus. A sphere (from Greek σφαίρα - sphaira, "globe Symmetry generally conveys two primary meanings The first is an imprecise sense of harmonious or aesthetically-pleasing proportionality and balance such that it reflects beauty or Gravitation is a natural Phenomenon by which objects with Mass attract one another The tidal force is a secondary effect of the Force of Gravity and is responsible for the Tides It arises because the gravitational acceleration experienced The moment of inertia of the object around the rotation axis can vary, and hence the rate of rotation can vary (because the product of the moment of inertia and the rate of rotation is equal to the angular momentum, which is fixed). This article is about the moment of inertia of a rotating object. Hyperion, a satellite of Saturn, exhibits this behaviour, and its rotation period is described as chaotic. TemplateInfobox Planet.--> Hyperion (haɪˈpɪəriən, or as in In Mathematics, chaos theory describes the behavior of certain dynamical systems – that is systems whose state evolves with time – that may exhibit dynamics that
Rotation period of selected objects
| Planet | Rotation period |
|---|---|
| Sun | 25. The Sun (Sol is the Star at the center of the Solar System. 379995 days at equator, about 35 days near the poles[2][3] |
| Mercury | 1047. 51 hours[4] |
| Venus | -5832. The VENUS ( V ictoria E xperimental N etwork U nder the S ea project is a cabled sea floor observatory operated by the University 444 hours[4] |
| Earth | 23. EARTH was a short-lived Japanese vocal trio which released 6 singles and 1 album between 2000 and 2001 93419 hours[4] |
| Moon | 655. 72 hours (synchronous toward Earth)[4] |
| Mars | 24. In Astronomy, synchronous rotation is a planetological term describing a body orbiting another where the orbiting body takes as long to rotate 622962 hours[4] |
| Jupiter | 9. 92425 hours[4] |
| Saturn | 10. 65622 hours[4] |
| Uranus | -17. 24 hours[4] |
| Neptune | 16. Neptune ( English|AmE] ] is the eighth and farthest Planet from the Sun in the Solar System. 11 hours[4] |
| Pluto | -153. 29 hours[4] |
See also
References
- ^ Explanatory Supplement to the Astronomical Almanac, ed. This article is about geographic magnetic and other poles on planets and other astronomical bodies Direct motion is the motion of a Planetary body in a direction similar to that of other bodies within its system and is sometimes called prograde motion. P. Kenneth Seidelmann, Mill Valley, Cal. , University Science Books, 1992, p. 48, ISBN 0-935702-68-7.
- ^ Rotation and pole position for the Sun and planets Rotation period in days is 360° divided by the coefficient of d.
- ^ Report of the IAU/IAG Working Group on Cartographic Coordinates and Rotational Elements of the Planets and Satellites: 2000PDF (215KB) pp7–8
- ^ a b c d e f g h i j Murray, Carl D. and Stanley F. Dermott (1999). Solar System Dynamics. Cambridge UP. ISBN 0-521-57295-9.
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