More than four hundred years ago, Johannes Kepler declared to the world that Mars travels on an elliptical orbit in his magnum opus the Astronomia Nova. This new elliptical orbital model of Mars not only perfected the heliocentric model of Copernicus in terms of providing it with a sounder mathematical foundation, and rendering it more able to predict the motion of Mars better than any traditional geocentric model like that of described by Ptolemy in the Almagest, but also challenged the ancient belief in the uniform circular motions of the planets. Kepler’s new model is not only one of the greatest achievement in astronomy, but also advanced our understanding into modern physical concepts like gravity.
In the sixteen hundreds, although more …show more content…
However, except for heliocentricity, the common denominator of these models is the perfect uniform circular motions performed by the planets. In the Timaeus, Plato seems to believe that uniform circular motion could explain the formation of thought itself, while to Aristotle, uniform circular motion is the sole capacity of a supra-lunary element called “aether”, which itself is eternal and unchanging. In the mind of a seventeen century astronomer, the perfect uniform circular motions in the geocentric models not only serve as a geometrical simplification of the supposedly mechanical universe, but it also carry many religious significances, especially when the planets are considered to be immortal gods or perfect ethereal …show more content…
According to Mr. Donahue in the footnote for Chapter 7, “Mars and Mercury are the only planets whose orbits differ enough from circles for that difference to have an effect observable by Brahe’s instruments. Mercury is too near the sun to afford reliable observations of its entire orbit. Therefore, only the observations of Mars could have led Kepler to his ‘new astronomy.’” As soon as he discovered that Mars orbits non-uniformly by sweeping out equal horizontal areas in equal periods of times, he realizes that the orbit of Mars can by no means be circular, but only be
In the sixteen hundreds, although more …show more content…
However, except for heliocentricity, the common denominator of these models is the perfect uniform circular motions performed by the planets. In the Timaeus, Plato seems to believe that uniform circular motion could explain the formation of thought itself, while to Aristotle, uniform circular motion is the sole capacity of a supra-lunary element called “aether”, which itself is eternal and unchanging. In the mind of a seventeen century astronomer, the perfect uniform circular motions in the geocentric models not only serve as a geometrical simplification of the supposedly mechanical universe, but it also carry many religious significances, especially when the planets are considered to be immortal gods or perfect ethereal …show more content…
According to Mr. Donahue in the footnote for Chapter 7, “Mars and Mercury are the only planets whose orbits differ enough from circles for that difference to have an effect observable by Brahe’s instruments. Mercury is too near the sun to afford reliable observations of its entire orbit. Therefore, only the observations of Mars could have led Kepler to his ‘new astronomy.’” As soon as he discovered that Mars orbits non-uniformly by sweeping out equal horizontal areas in equal periods of times, he realizes that the orbit of Mars can by no means be circular, but only be