They all made it to Terran pretty easily during the Aurvandil wars. Kale knows this first had as he was head of the Allied coordination between 'Moot and Astrocracies, which the primary reason he knew there wasn't much chance of fighting it out: he has literally helped coordinate the arrival of Astrocratic armies into Terran before.
The line seems to be somewhere around Paisly, really.
I believe we call that the Paisly Triangle.
