An oldie but a goodie!
Back in AutoCAD version 2.18 (circa 1985), Autodesk placed a sample drawing with AutoCAD named the Solar.DWG to demonstrate the precision of AutoCAD back in the early eighties. AutoCAD was based used 64bit floating point precision and the most accurate back then. With this Solar DWG you can see our solar system in 1:1 scale in kilometer units.
This would not be a good DWG to plot/print 1:1 full scale.
You can zoom all the way in on the Apollo Lunar Lander on the surface of the moon and read a plaque placed on it. You will notice the planets are from the eighties back when poor little Pluto was part of the planets, but today is not considered a planet any longer and is just a member of the Kuiper belt.
Read my Blog post from 2011. The reason for demonstrating scale and precision back in the early days by Autodesk was due to a spat between CAD companies when one claimed they had accuracy in a yet had no precision in a file based precision architecture in reality, and AutoCAD was 16 decimal places of glorious precision at the time, and still is.