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Earths faster motion makes Mars appear to be going backwards, the backwards motion, in fact, is what caused retrograde motion. --Ptloemy used Epicycles to explain how geocentrical models worked.

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The observed retrograde motion of planets led ptolemy to add blank to Aristotles system?

The observed retrograde motion of planets led Ptolemy to add epicycles to Aristotle's system. Epicycles were small circles that planets moved in on their larger circular orbits around Earth in order to explain the appearances of retrograde motion.


What are the similarities beween Copernicus' model of the universe and Ptolemy's model of the universe?

Both Copernicus' and Ptolemy's models aimed to explain the motion of celestial bodies in the sky. However, Copernicus placed the Sun at the center of the universe, while Ptolemy's model had Earth at the center. Both models used the concept of epicycles to explain the retrograde motion of planets.


How did Ptolemy account for the retrograde motion in his model of the Solar system?

Ptolemy's model of the Solar system accounted for retrograde motion by using a system of epicycles and deferents. The epicycles were smaller circles within larger deferents that allowed for the planets to move backwards temporarily. This complex system of circular motions aligned with the observations but was eventually found to be inaccurate.


What was Ptolemy trying to explain in his model by having the planets move on smaller circles that move on the bigger circles?

Ptolemy proposed the use of epicycles (small circles) within deferents (larger circles) to explain the observed retrograde motion of planets. The epicycles were used to account for the variability in a planet's speed as it moved along the deferent in his geocentric model.


What was the date Ptolemy discovered retrograde motion?

Yes. We now understand that all the planets travel round the Sun, and a planet's retrograde motion happens as the Earth overtakes the other planet in its orbit. The Earth goes round more quickly than all the outer planets from Mars onwards. In Ptolemy's model the Earth is stationary in the centre, and the planets move on circles and epicycles. Using Mars as an example and assuming the orbits of Earth and Mars are circular for simplicity, the Earth is at the centre and then Ptolemy's model has a circle (or deferent) round it with a radius of 1.524 units. The epicycle is a smaller circle whose centre travels round the deferent in 687 days. The epicycle has a radius of 1.000 units and Mars travels round this in 365 days. That was Ptolemy's geometric construction to explain the motion of Mars, which it does pretty accurately, and the retrograde motion happens when Mars on its epicycle moves close to the Earth. Ptolemy used additional epicycles to allow for what we now call eccentricity in Mars's orbit, and also for what we now understand is the orbit's inclination to the ecliptic.

Related Questions

Describe what produces the retrograde motion of mars. what geometric arrangement did Ptolemy use to explain this motion?

Earths faster motion makes Mars appear to be going backwards, the backwards motion, in fact, is what caused retrograde motion. --Ptloemy used Epicycles to explain how geocentrical models worked.


The observed retrograde motion of planets led ptolemy to add blank to Aristotles system?

The observed retrograde motion of planets led Ptolemy to add epicycles to Aristotle's system. Epicycles were small circles that planets moved in on their larger circular orbits around Earth in order to explain the appearances of retrograde motion.


Did Galileo's observations confirm the validity of retrograde motion of the planets?

No, Ptolemy did.


What are the similarities beween Copernicus' model of the universe and Ptolemy's model of the universe?

Both Copernicus' and Ptolemy's models aimed to explain the motion of celestial bodies in the sky. However, Copernicus placed the Sun at the center of the universe, while Ptolemy's model had Earth at the center. Both models used the concept of epicycles to explain the retrograde motion of planets.


How did Ptolemy account for the retrograde motion in his model of the Solar system?

Ptolemy's model of the Solar system accounted for retrograde motion by using a system of epicycles and deferents. The epicycles were smaller circles within larger deferents that allowed for the planets to move backwards temporarily. This complex system of circular motions aligned with the observations but was eventually found to be inaccurate.


How was Ptolemy's idea of retrograde different from Copernicus' idea of retrograde motion?

We now understand that all the planets travel round the Sun, and a planet's retrograde motion happens as the Earth overtakes the other planet in its orbit. That was also Copernicus's view although we now use Kepler's theory, but on this point the two models are in agreement. In Ptolemy's model the Earth is stationary in the centre, and the planets move on circles and epicycles, explained as follows. Using Mars as an example and assuming the orbits of Earth and Mars are circular for simplicity, the Earth is at the centre and there is then a circle (or deferent) round it with a radius of 1.524 units. The epicycle is a smaller circle whose centre travels round the deferent in 687 days. The epicycle has a radius of 1.000 units and Mars travels round this in 365¼ days. That was Ptolemy's geometric construction to explain the motion of Mars, and the retrograde motion happens when Mars on its epicycle moves close to the Earth.


Copernicus ideas that supported his ideas about the sun being at the centre of the Solar System?

he was a polish priest scientist stated retrograde motion occured whenever earth passes around another plant gained acceptance from people had a much simpliar way to explain retrograde motion than Ptolemy


Who believed in epicycles?

In ancient Greek astronomy, the concept of epicycles was proposed by astronomers like Eudoxus and later refined by Ptolemy in his geocentric model of the universe. The idea of epicycles involved planets moving in small circles on larger circles around the Earth to explain their observed retrograde motion.


What was Ptolemy trying to explain in his model by having the planets move on smaller circles that move on the bigger circles?

Ptolemy proposed the use of epicycles (small circles) within deferents (larger circles) to explain the observed retrograde motion of planets. The epicycles were used to account for the variability in a planet's speed as it moved along the deferent in his geocentric model.


What was the date Ptolemy discovered retrograde motion?

Yes. We now understand that all the planets travel round the Sun, and a planet's retrograde motion happens as the Earth overtakes the other planet in its orbit. The Earth goes round more quickly than all the outer planets from Mars onwards. In Ptolemy's model the Earth is stationary in the centre, and the planets move on circles and epicycles. Using Mars as an example and assuming the orbits of Earth and Mars are circular for simplicity, the Earth is at the centre and then Ptolemy's model has a circle (or deferent) round it with a radius of 1.524 units. The epicycle is a smaller circle whose centre travels round the deferent in 687 days. The epicycle has a radius of 1.000 units and Mars travels round this in 365 days. That was Ptolemy's geometric construction to explain the motion of Mars, which it does pretty accurately, and the retrograde motion happens when Mars on its epicycle moves close to the Earth. Ptolemy used additional epicycles to allow for what we now call eccentricity in Mars's orbit, and also for what we now understand is the orbit's inclination to the ecliptic.


Why does ptolemy include epicycles in his model?

Ptolemy included epicycles in his model to explain the retrograde motion of planets, where they appear to temporarily move backward in the sky. The epicycles were small circles that planets moved on while the center of the epicycle itself moved around Earth, providing a way to account for these complex observed movements within a geocentric system.


How was Copernicus' idea of planet movement different from ptolemy's?

Copernicus proposed a heliocentric model, where planets revolve around the sun, while Ptolemy's geocentric model placed Earth at the center of the universe with planets orbiting around it. Copernicus' model helped to explain retrograde motion more simply than Ptolemy's epicycles.