User Guide

MOONS
Planet has two moons, Nessus and Pholus, also named after Centaurs. The
tidal effects of these two moons were briefly discussed earlier. Here are a few
more specifics:
Earth’s MoonNessusN/M Ratio Pholus P/M Ratio
Mass (kg) 7.35 x 10
22
6.50 x 10
21
0.09 5.20 x 10
20
0.01
Radius (km) 1740 800 0.46 350 0.20
Dist. from planet (km) 3.84 x 10
5
2.00 x 10
5
0.52 1.00 x 10
5
0.26
Surface area (km
2
) 3.80 x 10
7
8.04 x 10
6
0.21 1.54 x 10
6
0.04
Mean gravity (m/s
2
) 1.62 0.68 0.42 0.28 0.17
Density (kg/m
3
) 3342 3031 0.91 2895 0.87
Synodic month (Earth days) 29.5 7.7 0.26 2.7 0.09
Synodic month (local days) 29.5 10.6 ñ 3.7 ñ
Synodic months/local yr 12.4 50.2 ñ 144 ñ
Angular radius (degrees) 0.26 0.23 0.88 0.20 0.77
OTHER PLANETS
Alpha Centauri B has been dubbed “Hercules” by the inhabitants of Planet. As
myth would have it, Hercules was, as much by fortune as by intent, a great
nemesis of the Centaurs. He slew Nessus (for attempting to violate Deianira),
Eurytion (for attempting to force a marriage with Dexamenus’ daughter,
Mnesimache) and even his former tutor Chiron (by accident, with a poison
arrow). Pholus was killed indirectly — by foolishly picking up Hercules’ arrow
and dropping it on his toe! Since Alpha Centauri B must either have ejected
or prevented the formation of other planets in this system, and could in time
be responsible for disrupting the remaining planets, the name is appropriate.
Eurytion (named after one of the Centaurs mentioned above) orbits Alpha
Centauri A at about half the radius of Planet. Among the planets orbiting the
Sun, Mercury bears the closest similarity to it.
A NEW SUN
APPENDIX 5
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