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- Planets appear to reverse motions at times.
- Ptolemy explained motions in terms of orbits (epicycles) carried on a larger orbit (deferent).
- Epicycle deferent ratios were very close to modern values of planet/earth orbit ratios. System worked very well.
- Contrary to popular myths, Ptolemy's system was not overly cumbersome, and it accounted for subtleties like the uneven motion of the Sun
- It is not Ptolemy's fault he did such a good job that it took 1500 years to improve on him!
- System began to seem cumbersome and inelegant.
- System inaccurate. Alfonsine tables out of date by 1500.
- Epicycle motions for Venus and Mercury opposite other planets.
- Epicycle for Sun's motion appeared in schemes for all other planets.
- References to now-lost ideas of Aristarchus of Samos
- Copernicus replaced epicycles with orbital motion of Earth.
- Less accurate than Ptolemaic system but conceptually simpler.
- Published as De Revolutionibus Orbium Coelestium (on the Revolutions of the Heavenly Spheres) 1542.
- Little immediate hostility. Earlier speculations on moving earth had been decreed heretical, hence moving earth idea could be lightly dismissed.
- One of most vigorous critics was Martin Luther.
- One of the last of the "scientific astrologers."
- Attempted to explain spacing of planet orbits by reference to Platonic solids.
- Kepler was reluctant to abandon perfectly circular motion (but despite his mystic tendencies, he did when the evidence required it).
- Kepler found many numerological relationships among the planets, of which "Kepler's Laws" are the three that have proven to have a physical basis.
- Kepler's concept of the Sun as center of solar system may have had a mystical basis.
- Copernican theory based on same observational data as Ptolemaic, hence no more accurate.
- Kepler turned to Brahe, who had the most advanced observational data.
- Orbits are elliptical, Sun at one focus, nothing at other.
- Radius vector sweeps out equal areas in equal times.
- Square of period proportional to cube of distance.
- Galileo and Kepler corresponded.
- Galileo defended Copernican astronomy but never wrote about Kepler's model.
- Galileo may have been repelled by Kepler's mysticism.
- Moral: even the best and most innovative workers can sometimes fail to recognize a major advance.
What else can I help you with?
Who contradicted Ptolemys geocentric model?
The heliocentric model proposed by Nicolaus Copernicus contradicted Ptolemy's geocentric model. Copernicus suggested that the Sun, rather than the Earth, was at the center of the solar system.
How did Copernicus realize that Venus is an inferior planet?
it was know in ancient times that Venus passes between the Earth and the Sun, and Copernicus had a model which had the Sun at the centre, so in his model Venus was closer to the centre, thus an inferior planet by definition.
What made Copernicus realize that Venus is an inferior planet?
it was know in ancient times that Venus passes between the Earth and the Sun, and Copernicus had a model which had the Sun at the centre, so in his model Venus was closer to the centre, thus an inferior planet by definition.
What is the major difference between the geocentric model in the heliocentric model?
The major difference between the geocentric and heliocentric models lies in the center of the solar system: the geocentric model places the Earth at the center, with the Sun and planets orbiting around it, while the heliocentric model positions the Sun at the center, with the Earth and other planets orbiting around it. The heliocentric model, proposed by Copernicus, is supported by observational evidence and eventually led to a better understanding of planetary motions, while the geocentric model was based on ancient beliefs and lacked empirical support.
Was Copernicus Danish?
No, Copernicus was Polish. Nicolaus Copernicus was an astronomer and mathematician who formulated the heliocentric model of the universe. He was born in 1473 in the Kingdom of Poland.
What is the main difference between keplers system and the Copernicus system?
Copernicus's system used circles and epicycles, just like the ancient Ptolemaic system, with the difference that by placing the Sun at the centre Copernicus could simplify the complicated paths taken by the planets through space. Kepler had the advantage of new accurate observations made by Tycho Brahe at the end of the 16th century, and these enabled Kepler to realise that by using elliptical orbits for the planets, the modelled positions could be fitted more closely with the measured positions. Kepler retained the idea of having the Sun at the centre and it is the model used today with slight modifications from Einstein's theory of relativity.
Why was Keplers model of the solar system good at the time?
because i say so!
Difference between multistore and working model memory?
what is the difference between the memory store model and the working memory model?
What difference between medical model and holistic model of care?
difference between holistic and medical models
Who contradicted Ptolemys geocentric model?
The heliocentric model proposed by Nicolaus Copernicus contradicted Ptolemy's geocentric model. Copernicus suggested that the Sun, rather than the Earth, was at the center of the solar system.
How did Copernicus realize that Venus is an inferior planet?
it was know in ancient times that Venus passes between the Earth and the Sun, and Copernicus had a model which had the Sun at the centre, so in his model Venus was closer to the centre, thus an inferior planet by definition.
Who made the helocentric model?
Copernicus
When did Copernicus realize that Venus is an inferior planet?
it was know in ancient times that Venus passes between the Earth and the Sun, and Copernicus had a model which had the Sun at the centre, so in his model Venus was closer to the centre, thus an inferior planet by definition. That was in about 1560.
What made Copernicus realize that Venus is an inferior planet?
it was know in ancient times that Venus passes between the Earth and the Sun, and Copernicus had a model which had the Sun at the centre, so in his model Venus was closer to the centre, thus an inferior planet by definition.
What is the main difference between Harrod-Domar growth model and Robert Solow growth model?
difference between horred-domer and solow model
Who created a model of the solar system with planets orbiting the sun?
Nicolaus Copernicus.
What is the major difference between the geocentric model in the heliocentric model?
The major difference between the geocentric and heliocentric models lies in the center of the solar system: the geocentric model places the Earth at the center, with the Sun and planets orbiting around it, while the heliocentric model positions the Sun at the center, with the Earth and other planets orbiting around it. The heliocentric model, proposed by Copernicus, is supported by observational evidence and eventually led to a better understanding of planetary motions, while the geocentric model was based on ancient beliefs and lacked empirical support.
