What is Space Opera?

It is both pointless and endlessly fascinating to debate what defines Space Opera and distinguishes it from standard Speculative Fiction.
Any story where a space-pirate wielding a space-axe could chop through a ray-shielded space-airlock, kidnap a beautiful space-princess and escape in a space-superdreadnought over a mile long, destroying at least one or perhaps two planets during the resulting space-battle, without this seeming in any particular out of place with the scale, scope, drive or moral code portrayed in the rest of the story, then the story is a Space Opera.
If you can add scene where the hero wrestles a dinosaur in the radio-active radium mine which is being flooded during a slave-revolt without breaking the established mood of the piece, then the story is a Space Opera.
Likewise, if the word “inconceivably” or “unimaginably” or “staggeringly” could be added as an adjective to describe the scale of the engineering, the temperature of beam-weapons, the speed of the vessels, the hardness of the space-armor, or the size of explosions and the resulting volume of destruction, or the beauty of the faultless heroine or the sex appeal of the evil space-emperor’s willful daughter, without seeming particularly out of place in the sentence, the story is a Space Opera.
Any lighthearted and straightforward space-adventure story which relies for its primary appeal on that sense of awe and wonder which comes of the contemplation of astronomical magnitudes both in the setting and the props, as well as the larger-than-life heroes and villains, you have a Space Opera.

Oh, and anything I write is Space Opera.