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Who created the idea of epicycles?
copernicus
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 geometric arrangements did ptolemy use to explain retrograde 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.
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.
Why does the geocentric system use epicycles when the heliocentric does not?
The geocentric system uses epicycles in order to create a model in which the earth is in the center of the solar system and the planets and sun look the way they actually look from the earth with the naked eye. The idea of epicycles was added by Ptolemy because without them his model was not consistent with what the ancients recorded about the position of the planets, the sun and the moon. It was important that the model be consistent with observation since the model was used for navigation and land travel. Once the telescope came into being it was evident that the geocentric model (which included the epicycles) was not consistent with was now observable in the sky, such as the way that Venus looked at different times of years (the phases of Venus). Therefore the geocentric model was abandoned for the heliocentric model. The heliocentric model's predicted movements that were closer to what was observable with the new technology. The heliocentric model does not "need" epicycles, in fact they would lead to false predictions inconsistent with what was observable.
What are epicycles?
In ancient astronomy, epicycles were imaginary circles within orbits used to explain the retrograde motion of planets. The concept was developed to account for the observed movements of planets in the sky.
Who created the idea of epicycles?
copernicus
What did ptolemy invent?
geocentric model & epicycles
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.
What are the small circles or rotations of an object called?
epicycles
Which planets' motions were described with epicycles in the Ptolemaic system?
In the Ptolemaic system, the motions of Mercury, Venus, Mars, Jupiter, and Saturn were described with epicycles. These epicycles were small circles that the planets were thought to move in while also orbiting the Earth on larger deferent circles.
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 geometric shape did the ancients used to describe motions of the planats?
The ancients assumed that everything moved in circles. Since that didn't work very well, they assumed that the motion was in circles-within-circles, called "epicycles". That was close enough given their generally crummy measuring devices. By the 1500's, measuring devices had become accurate enough to see that planets didn't move in epicycles either. Johanes Kepler determined that the planets move in ELLIPTICAL orbits, and we have since learned that all orbits are always elliptical.
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 geometric arrangements did ptolemy use to explain retrograde 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.
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.
Why does the geocentric system use epicycles when the heliocentric does not?
The geocentric system uses epicycles in order to create a model in which the earth is in the center of the solar system and the planets and sun look the way they actually look from the earth with the naked eye. The idea of epicycles was added by Ptolemy because without them his model was not consistent with what the ancients recorded about the position of the planets, the sun and the moon. It was important that the model be consistent with observation since the model was used for navigation and land travel. Once the telescope came into being it was evident that the geocentric model (which included the epicycles) was not consistent with was now observable in the sky, such as the way that Venus looked at different times of years (the phases of Venus). Therefore the geocentric model was abandoned for the heliocentric model. The heliocentric model's predicted movements that were closer to what was observable with the new technology. The heliocentric model does not "need" epicycles, in fact they would lead to false predictions inconsistent with what was observable.
