Very, very intrigued about the Rift

Ok did part of a playthrough after setting their spawn chance to 100....some tiles seem to be outlined in white. The outline spreads, but when I built a starbase in it it receded. Not sure what purpose is. 

Uploaded screenshot to steam, username there is No one

Put a spoiler alert next time. lol. That's amazing.

I think they have been called "Stellar Rifts" by devs. Some events in galciv2 featured rifts that caused weird shit to happen, like birth rate changes.

So i imagine if it is something that spreads out untill you "counter" it, it might be something that is related to events. for example a rift appears that causes effects that are either positive or negative or both for everybody within in influence. This way you might want to keep a certain rift if it influences your planets in a good way, and your enemies might try to build starbases/counters in it to deny you this advantage. Or if a bad rift appears, you would have to research the techs needed to close it in time before it grows out of control, perhaps a updated more elaborate version of the plague cure research. Coolest thing ofcourse would be if this sort of rift would spawn in a smart way: at the border of you and another empire, where the rift is beneficial for one empire and bad for the other.

However my original thoughts on the rifts were that they were going to be a terrain feature like wormholes for quick transport,  a form non-permament and/or changing impassable terrain or another variant of nebula/dustcloud which buffs/debufs ships inside.

Comment devs?

This is so cool. Terrain changing over time.