Ok i got another idea.

In the universe stars are born and they die, why not incorperate that into the game. Though make these events rare, very rare.

I supposing that a new star system would open up new planets and the death of a star would kill millions. Actully make the death of a star so dramactic, it's death fealt though EVERY sector (eg. the supernova of [name of star] has sent radition raining down apon the surface of all of your planets, ALL of your planets have had there class reduced by 1) or if you hold the planets of the dieing star (the star [name of star] has deid the planets of this star have been destroyed and the radation has reduced ALL of your planets classes by one).

Or even more dramatic (the star [name of star] has died and turned into a black hole sector [sector contianing black hole] is now impassable, anything in the sector has been destroyed by the blackhole).