The bar under the picture is a ruler of distance from the Sun, 0.001 AU to 10¹² AU, a tick at every power of ten. It is inked wherever these catalogs hold an object at the date shown and blank where they hold none; the notch is your own distance, the number the caption prints.
The blank between the farthest asteroid and the nearest star is the reach of these catalogs, not empty space: long-period comets and bodies too faint for these lists live there. The ink says whether anything is listed at a distance, not how much.
Nothing is enlarged: planets and moons are drawn at true size and distance, so most are a dot and a label until you come close. The caption gives the screen’s width at the distance of the object in the middle.
three.js r186 renders the scene (MIT License); the copy in vendor/ is byte for byte the one the Anatomy and Besseggen apps carry, with its license.
Type: Ysabeau Office by Christian Thalmann (Catharsis Fonts), SIL Open Font License 1.1; a subset is in fonts/ with its license. A second subset of the same face holds the Greek letters, superscript figures and the ʻokina the star and asteroid names use.
Every file was built once from the sources above by the pipeline in the app’s tools/ folder and travels inside the app. Nothing is fetched and nothing refreshes: the planets are computed for any date from 1900 to 2099 from the ephemeris that ships here.