Thank you for your insights. I especially liked John's funnel analogy
and David's elaboration on energy considerations; both helped
elucidate why crossing the event horizon is a one-way process.
GR was not a requirement of my grad program, although I had a very
good intro to SR while taking my bachelor's. Clearly there is much to
absorb, including some interesting vocabulary. What are your favorite
summer-reading books on this topic?