I know you can increase the active radius of the game and make the universe more alive that way, but that's incredibly CPU intensive. So I'm wondering if there's a way to still increase the radius but make things less intensive.

So, couple ideas on my own; have ships check that they're not on screen but still within the radius or whatever, and then refrain from firing; but have them do a "battle calculation" with any enemies they encounter, deciding who would win without all the physics updates and what not that cause the slowdown, and the loser retreats, so territory can still be dynamic outside the player's visible range, even if it's a bit hackish.

I'm sure there's a better solution but that's one I thought of in a few minutes. The goal though is to make the universe more alive with less CPU cost.