My DS6 does this. We have implemented a system in which we write down his big questions so that mom has time to research the question and give it the time it deserves. This has helped alot.
I like this too, especially since DDs hit me with the deep questions when I'm trying to get them ready for school or making dinner.
After I share some of my answers, I explain that these are very difficult questions that people have been wrestling with for many, many years. I give them suggestions for other people who would be interested in these kinds of discussions (like our rector).
