The ring marks the true-scale position of the Earth–Sun distance; it does not show its width. Only the inset is enlarged (×38,700).
Both rulers start at the same zero and share one linear scale. Artwork keeps its original proportions. A ruler represents the selected distance or a measurement not visible in this view.
In perspective269,000× timesMeasurements, assumptions & sources
The Earth–Sun distance, or astronomical unit, is the standard measure of separation between Earth and the Sun used in astronomy.
One astronomical unit is exactly 149,597,870,700 m. It is a useful Earth–Sun orbital scale, not the separation at every instant. Light takes about 8 minutes 19 seconds to cross it.