So I created a universe with 10,000,000 stars today...
mygoditsfullofstars 2001 space odyssey RAM memory overload slow
Surprisingly it actually kept running interactively without stuttering for about five minutes before crashing. According to google our galaxy contains about 300,000,000,000 stars which is only 30,000 times more than what I've got! Not bad, if I do say so myself. Of course, really this is a limit on objects in general, as my universe won't just be made of stars. There'll be planets, asteroids, rings, nebulae, supernovae, etc.
Looking at the stats it took up approximately 12 gigabytes of RAM. I can probably optimize that later a little bit. Not to mention the fact that probably only 1/100,000 of that was on screen at any one time (draw distance was set to about 10,000km), so some sort of off-loading to disk would be best too. Maybe I'll work on that next, I've never done compression before - could be interesting. Anybody out there know any good articles on compression techniques?
Might publish a proper journal entry tomorrow about the gravitation system and the octree, if I have time. I'm also meant to be going to a ball with my girlfriend.