The nature of black holes

Abstract

What is a black hole? It is a little bit difficult to answer this question. For general public, black holes frequently appear as strange celestial bodies in science fiction movies. However, for researchers, they are real presence in our universe and the regions of spacetimes in which nobody can escape even for light. Although the level of awareness is different, the black holes are mysterious to all of us. The black holes are mysterious so much so that we cannot really understand them up to date. What is the nature of the black holes? If people further ask. Probably, the understandings are different from person to person. On occasion, one even gets distinct answers from the experts in the physics of black holes. In this article, we will not provide some particularly striking ideas on this question, but we would like to tell readers the popularly accepted viewpoints in the community of this research field.