Hi, I have a question on can the black hole be formed? As we know, First, in the Swartzchild solution of GR, an observer outside the blackhole will find it takes infinity time for any object to fall into the blackhole. Second, a blackhole is formed by a star falling to its center. Now the question arises: when a star is falling, and nearly to form a blackhole, say, if one little piece of matter falls onto the star, it forms a blackhole. At this time, the time for a observer to see the last matter falling onto the star is nearly infinate, that means no matter how long a period of time T given, we will find a piece of matter small enough which falls onto the star taking longer time than T according to the observer outside. Then how can a blackhole form? I have been confused about it for long. Thank you.