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In Which way does a planet in retrograde motion appear to move?
Wiki User
∙ 12y ago
This question is a bit vague, as retrograde could describe a planet's orbit about its parent star, or its spin about its axis.
Retrograde is a term meaning in opposite of the norm. Most objects in our Solar System orbit the Sun in a counter-clockwise direction from the perspective of an observer above the Sun's north pole, and also spin in a counter-clockwise direction.
There are no known planets in retrograde orbit about their parent star, but there are a few objects in our Solar System which are in retrograde orbit (Halley's Comet among them). The largest known object with a retrograde orbit is Triton, a moon of Neptune; Triton orbits Neptune in a retrograde fashion. If Earth's moon had a retrograde orbit (instead of the prograde, or regular orbit, it actually has) the way Triton has about Neptune, the observable effects from the perspective of someone on earth would be the moon rising in the West and setting in the East (instead of rising in the East and setting in the West as it presently appears to), tides would be different, and the moon would likely not have the same side facing earth (so there would be no 'dark side of the moon' constantly hidden from earth; we would be able to see the moon spin) because the moon would likely not become tidally locked with the earth as it has become with its actual prograde orbit about the earth.
Two planets have a retrograde spin: Venus and Uranus. Uranus is actually, essentially, tipped on its side compared with the other planets, with its poles nearly pointing toward the sun and its equator (the line of latitude of the planet midway between its axes) spinning nearly perpendicularly to the solar plane. Venus is more closely aligned with the solar plane, but it spins in a clockwise fashion compared with the other planets. If we were on Venus, the effect of its retrograde spin (compared with being on Earth and its prograde spin) would be the sun would appear to rise in the West and set in the East instead of (as we observe on earth) rising in the East and setting in the West.
Wiki User
∙ 12y ago
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What is a retrogade planet?
A planet isn't retrograde - retrograde means the direction a planet moves in relation to how we see it here on Earth or other perspectives. Planets sometimes appear to move backward due to Earth moving as well.
The greek astronomers explanation for the celestial spheres did not encompass the phenomenon?
The Greek astronomer's explanation for the celestial spheres did not encompass the phenomenon of retrograde motion. The retrograde motion is the apparent motion of a planet to move in the opposite direction from the surrounding planetary bodies in the same system.
Why do the planets seem to move in a zig- zag pattern through the sky after many weeks?
Retrograde motion. Retrograde motion happens when the Earth moves around the sun faster than the observed planet: the planet is ahead of earth on in its orbit around the sun, but then the earth goes past that planet (in comparison to the sun) and as we go by the planet appears to go backward.
Do the planets in the solar system all move in retrograde motion?
YES. There are several meanings to "retrograde" in astronomy. In this case, I am assuming you mean the apparent "backwards" orbital motion of a planet that is sometimes seen. This is very obvious in the case of Mars. Also, all the outer planets show this "apparent retrograde motion". It's easy to forget, but Mercury and Venus also show this behaviour, but in a slightly different way.
Is Uranus in retrograde rotation?
Yes and so is Venus. The planets that move in retrograde (appear to move backwards against the starry sky) are Mars Jupiter and Saturn.
How did the Ptolemaic model of the universal explain retrograde motion?
If observed from one night to the next, a planet appears to move from West to East against the background stars most of the time. Occasionally, however, the planet's motion will appear to reverse direction, and the planet will, for a short time, move from East to West against the background constellations. This reversal is known as retrograde motion.
What is it called when a planet appears to move bacwards in is orbit?
"retrograde motion"
When a planet appears to stop in its orbit and move backwards this motion is called?
Apparent retrograde motion.
How can planet retrograde motion be explained by the Earth-center hypothesis By the Sun-center hypothesis?
In the Geocentric Hypothesis (Earth-centered), retrograde motion can only be explained by describing the motion of planets as complex, curlicue paths. In the Heliocentric Hypothesis (Sun-centered), retrograde motion is described as changes in relative motion as the Earth overtakes a slower-moving planet in an outer orbit, or is overtaken by a faster-moving planet in an inner orbit. In the Heliocentric Hypothesis, all planets move in more-or-less circular orbits at more-or-less constant speeds, but planets closer to the Sun move faster. Thus, the Earth can overtake and pass each of the outer planets, making them appear to move "backward" (retrograde) for a time.
What is a retrogade planet?
A planet isn't retrograde - retrograde means the direction a planet moves in relation to how we see it here on Earth or other perspectives. Planets sometimes appear to move backward due to Earth moving as well.
How do prograde rotation amd retrograde rotation differ?
Retrograde motion refers to the behaviour of an outer planet while it is overtaken by the Earth, around the time of opposition. At that time the planet appears to move backwards along the ecliptic.
The greek astronomers explanation for the celestial spheres did not encompass the phenomenon?
The Greek astronomer's explanation for the celestial spheres did not encompass the phenomenon of retrograde motion. The retrograde motion is the apparent motion of a planet to move in the opposite direction from the surrounding planetary bodies in the same system.
Why do the planets seem to move in a zig- zag pattern through the sky after many weeks?
Retrograde motion. Retrograde motion happens when the Earth moves around the sun faster than the observed planet: the planet is ahead of earth on in its orbit around the sun, but then the earth goes past that planet (in comparison to the sun) and as we go by the planet appears to go backward.
Which planet has retrograde rotation?
Retrograde rotation - From the Latin word "moving backwards" Retrograde rotation states that the planet Venus is the only planet in our solar system to move in an opposite rotation direction Uranus is a planet that rotates north to south do to the fact that it was most likely hit by a asteroid but this is not retrograde rotation
Do the planets in the solar system all move in retrograde motion?
YES. There are several meanings to "retrograde" in astronomy. In this case, I am assuming you mean the apparent "backwards" orbital motion of a planet that is sometimes seen. This is very obvious in the case of Mars. Also, all the outer planets show this "apparent retrograde motion". It's easy to forget, but Mercury and Venus also show this behaviour, but in a slightly different way.
What is a retrograde motion?
Rotation that is opposite to the common rotation of most objects in the solar system. Most of the planets rotate counter-clockwise, while Venus and Uranus rotate in a retrograde motion - clockwise. moving backward motion
What was Ptomeny trying to explain in his model by having the planets move on smaller circles that move on bigger circles?
to explain the motion of planets, especially the phenomenon of retrograde motion where planets appear to temporarily reverse their direction of motion. Ref: Andrew Liddle "An Introduction to modern Cosmology".
