ISSN:0008-8994    

DOI:10.1111/j.1600-0498.1992.tb00871.x

出版商:Blackwell Publishing Ltd    

年代:1992

数据来源: WILEY

摘要:

SummaryI have carried out a selective reworking of Chapter 32 of Kepler'sAstronomia Nova‐ which was the source of all his physical ideas ‐ and have established that no foundation exists either there, or subsequently, for what is nowadays known as ‘Kepler's distance law‘. By contrast, I show that his innovative approach led him to consider the component of velocity which is precisely perpendicular to the Sun‐planet line, and so to formulate motion taking place instantaneously in a circle round the Sun; this is exactly equivalent to the area law according to modern standards. Moreover, no other interpretation would have been compatible with Kepler's Aristotelian p

ISSN:0008-8994    

DOI:10.1111/j.1600-0498.1992.tb00872.x

出版商:Blackwell Publishing Ltd    

年代:1992

数据来源: WILEY

摘要:

SummaryKepler's investigation of Mars inAstronomia Novaprogressed through three distinct stages, each associated with an ‘ovoid’ curve of a particular grade (the egg‐metaphor was originated by Kepler himself). The geometrical separation of the first two proposed ovoids is greatest for their quadrant‐positions, so that is where Kepler assessed them. Via a previously‐unnoticed diagram, I exhibit the simple Euclidean construction he used to determine the optimum position of the Earth acting as a mobile observing‐platform. Then I extend Kepler's method to verify that, for at least half its orbit, the Earth will provide a viewing‐angle amply large enough to justify his conclusion that the observed quadrant‐position lay ‘in the middle’. Hence ‐ regardless of shape ‐ the planetary orbit is identified asa

ISSN:0008-8994    

DOI:10.1111/j.1600-0498.1992.tb00873.x

出版商:Blackwell Publishing Ltd    

年代:1992

数据来源: WILEY

摘要:

SummaryInAstronomia NovaKepler established the two laws that govern the motion of an individual planet. I show here that his achievement depended on the Euclidean ‐ geometrical ‐ method he invented to determine a typical point of each of the three curves he successively proposed (corresponding respectively to the three stages of his progress). At the final stage, Kepler's first flash of enlightenment was sparked by his discovery of a general construction‐rule for the (medial‐grade) curve he required; the second, by his realization that this rule would produce a perfect ellipse, described in accordance with the (Keplerian‐style) area law. This exact curve‐time correlation is notable for attaining, by modern standards, the status

ISSN:0008-8994    

DOI:10.1111/j.1600-0498.1992.tb00874.x

出版商:Blackwell Publishing Ltd    

年代:1992

数据来源: WILEY

摘要:

SummaryTen years after formulating the two laws that govern the motion of an individual planet, Kepler confirmed, inEpitome, that these laws could be generated independently, each by one of the two components of planetary velocity perpendicular to, and along, the Sun‐planet line in turn. Then, constrained by his Aristotelian principles, Kepler quantified the two separate physical causes of these component velocities: the single rotating solar force, and an individual planetary magnetism, respectively. Thus Kepler's achievement was to create a mathematically‐complete two‐cause explanation by which planetary motion is exactly resolved in accordance with modern stan

ISSN:0008-8994    

DOI:10.1111/j.1600-0498.1992.tb00875.x

出版商:Blackwell Publishing Ltd    

年代:1992

数据来源: WILEY