What are black holes This question is difficult to answer, since we do not have the necessary words to describe them. Scientists think that a black hole is a region of space into which matter has fallen and from which nothing can escape. So we cannot see a black hole. A black hole exerts a strong gravitational pull and yet it has no matter. It is only space. The exploration of black holes is just beginning. There are many speculations about them. There might be a huge hole at the centre of our galaxy swallowing up stars at a very rapid rate. Mankind may one day meet this fate. On the other hand, scientists have suggested that very advanced technology could one day harness the energy of black hole for human’s use on earth. These speculations sound like science fictions. But the theory of black holes is accepted by many scientists and astronomers.