How big rifts have to be to start farting out ships?

[Droll (OP)]

I'm currently watching a 15m km diameter rift grow and have been doing so for a couple in game years now.
There are no active constructs - when and at what size does it start to get spicy?

[nuclearslurpee]

Any size of rift can spawn an Invaders fleet, but the fleet will be larger and higher-tech the larger the rift has grown. Beyond this there isn't any documentation, Steve's changelog post on the subject was quite vague on this, probably on purpose.

[Droll (OP)]

Any size of rift can spawn an Invaders fleet, but the fleet will be larger and higher-tech the larger the rift has grown. Beyond this there isn't any documentation, Steve's changelog post on the subject was quite vague on this, probably on purpose.

Once sufficient ancient constructs are active, new rifts will be unable to form..

It would be nice to find out what a "sufficient amount" is

[nuclearslurpee]

Any size of rift can spawn an Invaders fleet, but the fleet will be larger and higher-tech the larger the rift has grown. Beyond this there isn't any documentation, Steve's changelog post on the subject was quite vague on this, probably on purpose.

Once sufficient ancient constructs are active, new rifts will be unable to form..

It would be nice to find out what a "sufficient amount" is

It's your lucky day. From the post immediately preceding:

3) If Invaders are active, the total % racial bonus provided by all active Ancient Constructs in the galaxy, regardless of which race has the qualifying population, will be used as a negative modifier to the growth of Aether Rifts (see later rules post). For example, if Race A has an Ancient Construct with with 50% Defensive Systems and an Ancient Construct with with 70% Propulsion, while Race B has an Ancient Construct with with 40% Biology, the growth rate of any Aether Rifts will be reduced by 16%. If the total modifier is greater than 100%, Aether Rifts will begin to decrease in size. If two races both have a qualifying population for an Ancient Construct, the bonus for the construct will only apply once for the purposes of Aether Rifts.

So "a sufficient amount" varies based on the size of the construct bonuses currently active. While not specifically stated I would assume that the same threshold prevents the formation of new rifts - as they would just collapse below what I assume is the 10m km diameter limit almost immediately.

[Droll (OP)]

Any size of rift can spawn an Invaders fleet, but the fleet will be larger and higher-tech the larger the rift has grown. Beyond this there isn't any documentation, Steve's changelog post on the subject was quite vague on this, probably on purpose.

Once sufficient ancient constructs are active, new rifts will be unable to form..

It would be nice to find out what a "sufficient amount" is

It's your lucky day. From the post immediately preceding:

3) If Invaders are active, the total % racial bonus provided by all active Ancient Constructs in the galaxy, regardless of which race has the qualifying population, will be used as a negative modifier to the growth of Aether Rifts (see later rules post). For example, if Race A has an Ancient Construct with with 50% Defensive Systems and an Ancient Construct with with 70% Propulsion, while Race B has an Ancient Construct with with 40% Biology, the growth rate of any Aether Rifts will be reduced by 16%. If the total modifier is greater than 100%, Aether Rifts will begin to decrease in size. If two races both have a qualifying population for an Ancient Construct, the bonus for the construct will only apply once for the purposes of Aether Rifts.

So "a sufficient amount" varies based on the size of the construct bonuses currently active. While not specifically stated I would assume that the same threshold prevents the formation of new rifts - as they would just collapse below what I assume is the 10m km diameter limit almost immediately.

D'oh I should have looked up, so basically a total of 1000% bonus worth of constructs need to be active in the galaxy to stop the aether rift growth / formation and anything beyond that shrinks them.