cap said:
2) The Death Star spends 30 minutes orbiting the planet to get a shot at the moon. Wouldn’t it be a lot faster to just blast the planet?

I don't know of any EU or scientific explanation offered before, but it seems to me there is overwhelming evidence that the Death Star can't just blow up Yavin.

The fact they don't is the evidence, and it seems perfectly satisfying to me. Who needs more? Would "Star Wars" have been a better film somehow with the following exchange?

GOON: Sir, Rebel base is 30 minutes away.

TARKIN: Rubbish. Just blow up the planet that we're going around.

GOON: No can do Moffy. It's a gas giant, and too big, and the resultant shockwave would damage the Death Star, and it lacks a solid core to aim the laser at, and a variety of other technobabble. Really, it's all kind of self-evident.

TARKIN: Oh very well. I'll be in the canteen.