It has same purpose as that of our earth - 'Nothing'. They are pretty much harmless entities (unless if you get too close to them) that are scattered across the universe. read more
If anything, the purpose of black holes is to drive physicists crazy trying to understand and explain them. Of course, assuming anything in the universe has a purpose for existing is a fallacy. Objects in the universe form and behave according to the laws of physics and chemistry (except black holes, the rebels!), not to carry out a task. read more
But an intriguing theory suggests there's much more to the cosmos than meets the eye — and that black holes play an integral role in what our universe is actually trying to achieve. It's tempting to think of the universe as a meaningless repository for celestial objects like planets and stars. read more