One question, several references
Size and distance: two ways of looking at the Universe
Distinguish a celestial body’s diameter from its distance, using the Sun, Moon and Proxima as examples.
Try it in the explorer →A size describes the object
A diameter crosses a celestial body. A length measures an object’s extent in a defined direction. In Size mode, objects are ordered by these dimensions and their positions are arranged for readability.
A distance separates two points
The three journeys in Distance mode use centre-to-centre distances. They also keep diameters at the same scale: a planet may become too small to see and receive an explicitly symbolic marker.
Why Proxima comes before the Sun
Proxima is smaller than the Sun but much farther from Earth. Appearing earlier in a size journey therefore says nothing about how close it is.
This journey’s references
Sources and method
Dimensions and conventions are those of the fact sheets linked above. Illustrations remain interpretations. Providing a documentary source does not independently certify every catalogue value.