Life of Stars

Modern astrophysics is opening as a book of puzzles to the scientists. The black hole is one of these latest puzzles of astrophysics. Although the theory of general relativity and gravitation predicts the inevitable formation of black holes in the galaxy, they have not yet been observationally demonstrated. If, however, they do form according to the prediction of the theory, there may be as many as a billion or so of them in our Galaxy. As such, they should have a tremendous importance in the galactic phenomena, and fortunately, this aspect has not remained ignored by the theoretical physicists. What are then these black holes and how can they be formed? Why are they so called and what possibilities are there to actually ¿observe¿ them? These questions and the like we shall discuss briefly in the present section. We have already seen that stars with masses less than about 1.4 M invariably end their life as white dwarfs. These stars meet heir demise peacefully. But any star having a mass greater tan 1.5 M has a chance to explode violently at a certain stage of its evolution, unless the catastrophe is prevented by rotation of the star or loss of part of its mass .