I've been confused about something ever since I first learned about black holes. Perhaps someone can help clear this up for me. Suppose we (sitting here on earth) observe a clock sitting on the surface of an imploding stellar core during a supernova, destined to become a black hole. (By observe, I mean we have a crystal ball, so no confusion about light traveling to us). As the core approaches the point of forming an event horizon, before a black hole has actually formed, we observe the clock slows down tremendously. Now a millisecond on the clock takes a month of our time. Closer to forming the event horizon, now an attosecond takes a billion years of our time. From this perspective, it seems more proper to me to say that the stellar core is frozen just before forming an event horizon, from our standpoint here on earth. All black holes are in fact "asymptotically" black holes. All hypothetical discussion about "the interior of a black hole", if it is relevant to us as observers here on earth, should really be about the physical state of the collapsing core, frozen in time, frozen at the exact point of almost forming an event horizon. Yet astrophysicists and cosmologists routinely discuss the interior of a black hole in a manner that seems to shrug over this point. I've discussed this with a well-known astrophysicist, and the best he could come up with was that Penrose diagrams are the best way to view this. Can anyone do better, or explain how Penrose diagrams help here?