Although I'll admit, the rising sun is a pretty sure thing, we all know that just because something has happened several billion times in the past is not necessarily a guarantee that it will happen in the future. I think I remember a biblical story that leaves some doubt about the inevitibility of the sun's movement, if you believe in such things, and if you've ever invested in the stock market, you'll be familiar with the disclaimer the brokers always put in their brochures. The point we all have to remember is that language is chosen by the speaker. He has to have some reason for choosing what he does. If your speaker here looks at the situation of the sun rising and analyzes it as an event he believes, on the basis of his prior experience, is a good bet...but also feels the need to acknowledge that he cannot predict with certainty what the future will bring, he will say: "The sun will rise tomorrow." And, if your speaker says, "The sun is going to rise tomorrow.", I'd have to suggest that means he believes he has evidence of that event arising as he speaks. Again, ...Perhaps it is more likely that he might say, "The sun is going to rise in a few minutes." That's more likely because he sees the faint glow of light in the eastern sky.Szwagier, I'm not sure why you have pointed to the will in, "I will this to happen." Surely there can be no confusion here. These wills are just not the same!!!
Larry Latham
I think the difference is that (will) in the first three examples is an auxiliary and in the fourth it's a verb. Different animal, different meaning. Nevertheless, your suggestion that the full 