Just installed DA yesterday and was running my first game last night. On a small galaxy with five other civs. I think I left mega-events on out of curiosity. I haven't been playing for long but I've already had notifications of two planets destroyed by meteor/asteroid hits. There aren't a huge number of habitable planets on the map so my question is this, are the planets destroyed only ever PQ 0 planets or could the game randomly pick an inhabited world ?

Secondly, is PQ based on your ability to colonise a world ? I ask because I started with barren world colonisation and encountered several barren worlds rated PQ7 to 13. At the same time I ran across aquatic worlds never rating more than PQ4 - is that because I didn't have the appropriate colonisation tech ? I thought that the tech just gave you the ability to land on a planet and eventually remove the productivity deficit, I didn't think it altered PQ.