Scale Solar System

Ruben Said:

Where could I find a scale model of the solar system in action with the planets revolving and rotating?

We Answered:

Many. They are called orreries. There is one on the internet too (see reference). The first reference has a picture of one at the Smithsonian.

Before the orrery, there was something similar called the armillary sphere, invented by Eratosthenes (aka spherical astrolabe, armilla, or armil).

The tellurian is similar to orrery. Sometimes an orrery was called a planetarium.

Kathleen Said:

If the solar system were 10 cm across, how big would the Milky Way galaxy be on that scale?

We Answered:

Milky Way approx. diameter = 9.46x10^17 km (100,000 light-years)
Neptune's orbit = 4.50x10^9 km

Thus, at such a scale, the Milky Way would be 2,102,222,222 cm, or 21,022 km (the Earth is only 12,742 km). So not quite twice the width of Earth.

EDIT: Serves me right doing math really late at night. Milky Way measurement was the diameter while Neptune's orbit was radius. Thus, the answer is half of what I originally came up with (10,511 km or approximately the size of the Earth).

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