Actually they were a lost tribe of humans, humans not humanoids. They had some alien words like centon, micron, and yaren to give the setting an unearthly feel to it. They really went overboard in giving them superpowers in Galactica 1980 and UFO style saucer spaceships with invisibility cloaks to fly around in.if every hundred years we can have a supernova that threatens to destroy the galaxy, what does this mean?
I don't see the problem, as the movie certainly did not claim that all supernova explosions threaten the galaxy. Only this single one did - and the unlikeliness of such a thing may be the reason Spock found it so difficult to convert anybody to his cause.
the same is true of the original Battlestar Galactica, they used the term "Galaxy" as a substitute for the word "Star System"
But they were entitled to, as the heroes weren't human; their "English" featured a lot of alien expressions anyway. Same with Cylons: "vector" instead of "sector" to describe a point or region in space. In neither case was there any indication that these words would also be in use in their more usual sense (galaxy = structure like Milky Way, vector = mathematical expression of direction times magnitude).
Timo Saloniemi
I like the more realistic tone of the new Battlestar Galactica, at least they did try to get their science right.