No, it's not a stupid idea. I just don't think it's an idea suitable
for US. US is more a gravity simulator, not a universe/galaxy
simulator.
What you want, is either Celestiaa or Space Engine. Of
the two, Celestia is more stable, and will operate on
just about any PC. However Space Engine requires a
really good PC, as it also allows you to cruise the entire
known universe, visit any galaxy, and go to any star in
any galaxy. Plus the miriad of objects in our galaxy.
Here's the link to space engine, google celestia if u want
to try that. Both are free. Celestia has masses of addons,
including fictional systems, spaceships n just about anything
you can think of.
http://en.spaceengine.org/load/core/spaceengine_0_93_full_version/2-1-0-1Another great program is Orbiter, which is also a simulator, but is a spaceship
simulation, but is limited to the solar system. But you need to know
a little of Orbital Mechanics to get the most from it. There's masses
of tutorials on learning how to use it and masses of addons,
from bases, to ships to equipment for transport you name it,
as well as missions you can do. Google it, u should be able
to find videos on youtube for each of these to get a peak.
Hope you enjoy them