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Triangles in the Sky: Trigonometry and Early Theories of Planetary Motion - Summary: Parameters of the Basic Ancient Model

Author(s): 
Sandra M. Caravella (New Jersey City University)

Table 3 exhibits the parameters for the basic ancient model that are computed by using the data and techniques described in the previous two sections.

Sidereal Period T

(in years)

Synodic Period S

(in years)

r/R

Mercury

1

0.3

0.37

Venus

1

1.6

0.72

Mars

1.9

2.1

0.66

Jupiter

11.8

1.1

0.19

Saturn

29.5

1.0

0.11

Table 3

With these parameters in hand, it is fun to revisit Figure 6 and feed in the appropriate parameters for each planet. Running the animation at the same speed for each planet allows us to compare the various journeys of the planets as they make their way around the ecliptic. From the swift movements of Mercury to the lumbering journey of Saturn, we see the same general pattern with important individual differences.

Sandra M. Caravella (New Jersey City University), "Triangles in the Sky: Trigonometry and Early Theories of Planetary Motion - Summary: Parameters of the Basic Ancient Model," Convergence (August 2010), DOI:10.4169/loci003120