The apparent backward motion of a planet when it appears, as observed from Earth, to reverse its natural direction of travel and move backward in the zodiac.
When a planet reverses its usual direction of travel (west to east) for a few weeks. When the planet is traveling in the reverse direction (east to west) it is said to be retrograding. After a few weeks the planet reverses again and resumes its normal course.
Westward or backward drift of a planet resulting from the forward motion of the earth as it passes the planet.
Orbital or spin motion in the opposite direction from prograde motion; in the solar system, retrograde motions are clockwise as seen from above what we call the North Pole of the Earth.
Motion which is backwards relative to the usual direction. Usually, an apparent westward, or backward, motion of a planet among the stars, caused by its lapping, or being lapped by, another planet.
for orbital motion in the solar system, motion that is clockwise in the orbit as seen from the north pole of the ecliptic; for an object observed on the celestial sphere, motion that is from east to west, resulting from the relative motion of the object and the Earth. (See direct motion.)
The normal direction of a planets motion as we see it from Earth is West to East against the background of the stars. Occasionally, however, the planets outside the Earth's orbit can be seen, over a number of nights, to slow, eventually to stop and then to reverse direction (i.e. East to West against the background) for a time! They will then appear to slow again, stop and resume their original direction. This caused real problems for the geocentric theory, and Plotemy's attempts to explain the observed motion led to the theory becoming very complex. The correct reason for this motion was first realised by Copernicus in his heliocentric theory, but it was not until Kepler produced his work that it was conclusively understood. The correct theory is that as Earth's orbital velocity is greater than the planets outside it, so it will slowly catch up and overtake these planets. The effect of this as viewed from Earth is that their velocity across the sky will slow down as Earth closes in to 'overtake' it, as Earth is passing their path will seem to reverse for a short time and once passed the path will revert to its original course.
Motion in a direction opposite to what is usual (in the solar system clockwise motion as viewed from above the sun's north pole is considered retrogate).
backward (westward) motion of the planet among the stars, resulting from the fact that it is viewed from the moving Earth. It is the motion that a planet has when its right ascension is decreasing. Each year, when Earth passes a superior planet, such as Mars, the planet appears to move backward for a short time. It is the same effect you see when two trains are running in the same direction on side by side tracks. The slower train appears to be moving backward.
When a planet appears to be moving backwards ("in reverse gear") in the zodiac (as opposed to direct motion). See also Retrograde Zone Info.
when a solar system object (e.g., a planet) moves ``backward'' (westward) with respect to its normal eastward drift against the stars. It happens when the Earth is closest to the object.
Backward, westward loop traced out by a planet with respect to the fixed stars.
An apparent westward motion of a planet on the celestial sphere or with respect to the stars.
Reversal in direction of a planet's apparent motion against the stellar background.
A planet moving from east to west in celestial longitude is moving retrograde or looping.
Every so often, each planet ceases its normal forward movement around the zodiac (called "direct motion") and appears to move backwards ("retrograde motion") for a time. This occurs whenever the Earth passes up the other planet as they both orbit the Sun, similar to how a slower car appears to move backwards when you pass it at higher speed on the highway. After a time, the planet stops this reverse motion and resumes its normal, direct motion, again.
If we were above the solar system in the direction of the North pole. All the planets would revolve around the Sun in an anti-clockwise direction. This is called direct motion. The opposite, anti-clockwise motion, is called retrograde. The planets which rotate on their axes in a retrograde direction are Venus, Uranus and Pluto. Moons mainly revolve directly about their planets, the main exception is Triton, the largest moon of Neptune.
describes an orbit about the Sun which is the opposite of the direction of the orbits of the planets. Halley's Comet is a retrograde comet.
the apparent backward (west to east) motion of planets against the background of the stars that results from the difference in orbital speed and distance of the planets
The apparent westward motion of a celestial body with respect to the stars. Retrograde motion is a perspective effect produced when an inner body passes an outer body in their respective orbits.
This is a phenomena where a planet appears to move West-to-East against the field of stars instead of the normal East-to-West direction. This occurs when the orbit of the Earth overtakes the orbit of the observed planet.
The temporary backwards or westward motion of a superior planet against the background of the stars that results when the faster-moving Earth on on it's shorter orbit passes that of the the superior planet.
The phenomenon where a celestial body appears to slow down, stop, them move in the opposite direction. This motion is caused when the Earth overtakes the body in its orbit.
When a planet seems to slow down, stop, and move backwards from east to west for a short time. Mercury and Venus exhibit retrograde motion.
Apparent backward motion of a planet. This is an illusion caused by the relative motion of the Earth and other planets in their elliptical orbits.
Normally, a planet's motion through the sky is from west to east (direct motion). However, at such times where either the Earth overtakes an outer planet, or is overtaken by an inner planet, the planet will temporarily stop moving west - east and start going in the other direction, i.e. from east to west. This effect is known as retrograde motion. It should be noted that this does not mean that the planet in question is actually moving around the Sun in the opposite direction, it is just a result of the Earth's motion. The superior planets all exhibit retrograde motion around the time of opposition, so it is easy to observe; the inferior planets, however, do it around the time of inferior conjunction, and so it is difficult, or should I say impossible, to observe.
The temporary apparent backward motion of a planet in the sky, from east to west, caused by the geometry between the Earth and planet. Due to this geometry, only planets that orbit outside the orbit of the Earth are observed to have retrograde motion.
The apparent backward motion of a planet when it appears, as observed from Earth, to reverse its travel direction relative to the zodiac.
The apparent backward (westward) motion of planets as seen against the background of stars.
When a body moves around the Sun in the opposite direction to Earth.
The planets generally move from west to east in the sky. Occasionally, one of the planets seems to slow down, stop, and loop backwards, moving from east to west for a short time. After a short time, all the reverse happens and all is back to normal. The planet did NOT stop or move backwards in its orbit; for a while, the Earth was moving faster than than the planet, overtaking the planet for a short time, making it seem to lag.