Here's some awesome software which, like Musicbee, is developed by one guy in his spare time. Amazing.
Warning #1 - I'm not responsible for any days/weeks you may lose in this software.
Warning #2 - It is in early 'beta' and therefore has some bugs/crashes. Also user interaction (Eg navigation) isn't always easy.Video: Scale of Space Engine: Earth To Universe Zoom
Remember, after leaving the Milky Way at 2:20, each pinpoint of light from then onwards are tens of thousands of explorable galaxies; each galaxy contains millions of stars, and most stars have several unique explorable planets orbiting them...
Video: YT user Solaris SE
Space Engine is a 'model' universe. It only has 300,000 real objects from astronomical databases. The other billion objects are 'procederal' - meaning they are created by algorithms.Video: Terrains
Each star has a unique configuration of unique explorable planets and moons.(More Videos From LifeLive42 here)
Download here: http://en.spaceengine.org/