Random Thoughts: Justice League - Where Do Superman's Powers Come From?

I recently discovered that Justice League was playing on Netflix. This made me extremely happy. It's the "In the Blackest Night" episode where Green Lantern is on trial on Ajuris 5. The JL goes to rescue him, and Superman is kicking alien butt, which is always fun, but then I thought, "How does he have his powers on that planet?"

Superman is a comic that I would love to follow, but there is just too much to catch up on. I pick up some of the stories in the trades, but mostly, I get my Superman fix from the movies, TV shows, and occasionally Wiki. I was always under the impression that Superman's powers came from the yellow sun. Has that changed? If so, when and what's the new version?