Someone explained to me that apparently in later comics it has been revealed that the gamma radiation that his anger resonates with is drawn from something called the green door which is created by a character known as the one below it all who is more or less Satan (gods nasty alter ego).

And apparently this is limitless so if he gets pissed enough he could destroy the universe as we know it.

Right… but then anger itself would require huge amounts of calories. You can’t just create energy.