A. Planetary Distances:
A scale of 1 cm:5×106 km (1 cm : 5 million km) can be used to make a model for for planetary distances.
To calculate the model distance of planets to the Sun divide the actual distance of the planet by 5 million km. The answer will be measured in centimeters, cm.
For example: The actual distance of Mercury to the Sun =57 million km
model distance =57 million km ÷ 5 million km = 11.6 cm
For information about planet distances from the Sun and planet diameters, check out Kids Astronomy.com.
B. Planetary Sizes:
A scale for comparing planetary sizes is 1 cm:2×103 km (1 cm: 2 thousand km).
To calculate models of planets, divide the actual diameter of each planet measured in kilometers by 2,000 km.
Using the scale that 1 cm = 2,000 km, what is the scale for the Earth and its Moon?
1. The diameter of the Earth is 12,755 km.
12,755 km ÷ 2,000 cm/km = 6.377 cm or 6.4 cm
The scale diameter of the Earth would be 6.4 cm
2. The diameter of the Moon is about 1/4 the diameter of Earth.
6.4 cm ÷ 4 = 1.6 cm
The scale diameter of the Moon would be 1.6 cm.
C. Scale for Distance and Celestial Body Sizes
Trying to produce a scale model of each part of the solar system is difficult. While the scale of 1 cm: 2 thousand km works well with comparing the planets, if this same scale was used for diameters of the celestial bodies, the models would be too small.
The solar system diagram shown above is not to scale in any way. The purpose of the model is just to show the planets in relation to each other and to the Sun.
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