Quotes: Defining characteristics of space opera (including "new" variety)

From Kelly Melcher's "Defining the Genre: Space Opera" post at Fandomania:

1. Attributed to Wilson Tucker: Space opera has "a space ship", is an "adventure", & is "at least a little formulaic."
2. Attributed to Hartwell and Cramer: Space opera is "a fast paced, heroic, interplanetary guilty pleasure".
3. Space opera has "epic scope, escapist adventure, and of course space travel."
4. New space opera: "more pessimistic, darker and more cynical", "travel done by other means than spaceships", "exploring artificial intelligence and what happens when we modify ourselves."