Newbie question: Sphere, Ring world?

[terahsu]

I happened to come across a very funny article..
I read on till the 62th way.
"62. You keep playing the game for 100 years after winning, just so you can make a sphere world."
Yes, I know there're such things in Se-IV.
But I am really confused about these stuff:
Sphere world, Ring world..??
I think they are uselss to conquer enemy.
And they don't constitute as a victory condition
like Building Wonders in Age of Empires.

Could somebody tell me what're their purposes?
Do they make a difference in conquering galaxy,
or they are just like pretty clothes for a king?

---101 ways to tell if you're addicted to SE-IV.
http://www.angelfire.com/tv2/NewAgeS...Addiction.html