Draw Earth two pixels wide and you need 735 screens to reach Neptune. Textbook diagrams are all compressed.
Planets shown side by side are never to scale. At true scale the planets become nearly invisible dots and most of the page is empty.
At that scale the Sun sits about 3,000 pixels away, and Neptune needs 735 screens.
8 minutes 19 seconds to the Sun, 4 hours 10 minutes to Neptune, and 4 years 3 months to the nearest star beyond.
Even the asteroid belt is sparse — roughly a million kilometres between asteroids, which is why probes cross it without concern.