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Both Ptolemy and Copernicus used the circle as the basic element of the orbits, but they both knew that a simple circle was not correct in describing the movements of the planets accurately.
The way they worked round the problem was to use epicycles. An epicycle was a small circle whose centre moved round the main circle, and the planet remained stationary on the epicycle. In other words the line joining the planet to the centre of the epicycle stays in the same direction all the time. This is actually a good approximation to an elliptical orbit because it reproduces the effect of the planet moving closer and further away once during one revolution, and geometrically it is equivalent to having the planet going round a circle but with the Sun offset from the centre (by a different amount for each planet).
That is why the model lasted for as long as it did - 1500 years, until Tycho Brahe made observations and recorded the planets' positions with such high accuracy that Kepler was able to deduce the ellipse as the more correct form for planets' orbits. He did this by studying Tycho's measurements of the orbit of Mars, which has a higher eccentricity factor than all the main planets except Mercury which is difficult to observe, and there was just enough difference for Kepler to spot it.
The major difference between Ptolemy's model and Copernicus's was that the Earth was at the centre when the Ancient Greeks studied the problem, and the Sun had an orbit, while Copernicus in the early 16th century imagined the Sun at the centre. Later scientific discoveries by Newton and his successors demonstrated the sun-centred theory as superior.
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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.
What were the similarities between Ptolemy's model and Copernicus' model?
Both Copernicus heliocentric and the Ptolemaic models agreed on the need for epicycles. These were miniature orbits that the celestial bodies travelled on as well as their normal orbits.Copernicus still invigaed the bodies orbiting in perfect circles and had to put these in to explain some of the movements of the planets. This may have contributed to his ideas being largely dismissed as it was just as complicated as the already established model. It was not until Kepler proposed elliptical orbits was this problem resolved.
How was Copernicus' model of the universe different from Ptolemy's model?
The main difference was that Ptolemy's model was geocentric (Earth-centred) and Copernicus's was heliocentric (Sun-centred). Ptolemy's model came from ancient times while Copernicus's was much later (1543). Both models represented the planets' orbits by using combinations of circles and epicycles to explain the way the planets move among the stars. Copernicus found that the orbits of the inner planets could be explained more simply. That is to say that the epicycles used for all the orbits were smaller, and for the inner planets a lot smaller. Both models represented the planets' positions with reasonable accuracy given the crude observational methods used in those days. Until gravity and the laws of dynamics were discovered about 150 years after the publication of Copernicus's system, there was no way of deciding which model was the 'right' one.
What was the the model solar system that was thought to be correct before Copernicus?
It was Ptolemy's model. Ptolemy's model came from ancient times while Copernicus's was much later (1543).Both models represented the planets' orbits by using combinations of circles and epicycles to explain the way the planets move among the stars.Copernicus found that the orbits of the inner planets could be explained more simply. That is to say that the epicycles used for all the orbits were smaller, and for the inner planets a lot smaller.Both models represented the planets' positions with reasonable accuracy given the crude observational methods used in those days.Until gravity and the laws of dynamics were discovered about 150 years after the publication of Copernicus's system, there was no way of deciding which model was the 'right' one.
Who could not predict the movements of the planets accurately?
Ancient astronomers like Ptolemy and Copernicus could not accurately predict the movements of the planets because they were working with models that did not accurately capture the true nature of the solar system. Their geocentric models, which placed the Earth at the center of the universe, were unable to accurately predict the movements of the planets due to their circular orbits and epicycles. It wasn't until Johannes Kepler formulated his laws of planetary motion based on observations by Tycho Brahe that more accurate predictions became possible.
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.
What were the similarities between Ptolemy's model and Copernicus' model?
Both Copernicus heliocentric and the Ptolemaic models agreed on the need for epicycles. These were miniature orbits that the celestial bodies travelled on as well as their normal orbits.Copernicus still invigaed the bodies orbiting in perfect circles and had to put these in to explain some of the movements of the planets. This may have contributed to his ideas being largely dismissed as it was just as complicated as the already established model. It was not until Kepler proposed elliptical orbits was this problem resolved.
How was Copernicus' model of the universe different from Ptolemy's model?
The main difference was that Ptolemy's model was geocentric (Earth-centred) and Copernicus's was heliocentric (Sun-centred). Ptolemy's model came from ancient times while Copernicus's was much later (1543). Both models represented the planets' orbits by using combinations of circles and epicycles to explain the way the planets move among the stars. Copernicus found that the orbits of the inner planets could be explained more simply. That is to say that the epicycles used for all the orbits were smaller, and for the inner planets a lot smaller. Both models represented the planets' positions with reasonable accuracy given the crude observational methods used in those days. Until gravity and the laws of dynamics were discovered about 150 years after the publication of Copernicus's system, there was no way of deciding which model was the 'right' one.
What was the the model solar system that was thought to be correct before Copernicus?
It was Ptolemy's model. Ptolemy's model came from ancient times while Copernicus's was much later (1543).Both models represented the planets' orbits by using combinations of circles and epicycles to explain the way the planets move among the stars.Copernicus found that the orbits of the inner planets could be explained more simply. That is to say that the epicycles used for all the orbits were smaller, and for the inner planets a lot smaller.Both models represented the planets' positions with reasonable accuracy given the crude observational methods used in those days.Until gravity and the laws of dynamics were discovered about 150 years after the publication of Copernicus's system, there was no way of deciding which model was the 'right' one.
How does Ptolemy's models model of the universe compare Aristotle's model?
Both Models Show That Celestial Objects Have Circular Paths
Who could not predict the movements of the planets accurately?
Ancient astronomers like Ptolemy and Copernicus could not accurately predict the movements of the planets because they were working with models that did not accurately capture the true nature of the solar system. Their geocentric models, which placed the Earth at the center of the universe, were unable to accurately predict the movements of the planets due to their circular orbits and epicycles. It wasn't until Johannes Kepler formulated his laws of planetary motion based on observations by Tycho Brahe that more accurate predictions became possible.
How did Copernicus explain the retrograde motions of the planets?
All the models explain retrograde motion because it is such an obvious phenomenon. In Copernicus's model an outer planet goes into retrograde motion when the inner planet overtakes it so that it appears from the inner planet to be going backwards along the ecliptic.
How does Ptolemy model of the universe compare with Aristotle's model?
Both Models Show That Celestial Objects Have Circular Paths
How does Ptolemy's model of universe compare with Aristotle's model?
Both Models Show That Celestial Objects Have Circular Paths
How does Ptolemy's. model of the universe compare with Aristotle's model?
Both Models Show That Celestial Objects Have Circular Paths
How does ptolemy's model of the universe compare with aristotle's model?
Both Models Show That Celestial Objects Have Circular Paths
Which scientist made highly accurate measurements that disproved the theories of ptolemy and Copernicus?
Tycho Brahe designed new equipment to measure planets' positions with unprecedented accuracy. Tycho's observations of the planets' orbits led to his alternative model which still had the Earth at the centre with the Sun orbiting it, but with the five other known planets orbiting the Sun. But Tycho's measurements were used by his assistant Kepler to produce an entirely new theory in 1609 with the planets in elliptical orbits, all orbiting the Sun as in Copernicus's model of 1543. Kepler's theory is still used today. It's important to remember that the theories of Ptolemy and Copernicus are not 'wrong', it would be better to say they are not as accurate as Kepler's theory. As models, all three of them predict the planets' positions fairly accurately.
