PlanetsCentral

I found that when my ship arrived at a new planet there were already significant colonists, some factories, mines and defenses already present. What are the parameters of this? Will I find this when sending ships to all unowned planets? Or does this happen for a limited number of turns?

I'm not sure what effect you're referring to, but PlanetsCentral games start with more than one planet per player. You don't need to go there first, you just own them.

This might be unusual if you have only played Tim's MASTER/HOST before.

--Stefan