Black holes are made from the death of stars. Let me explain the process you see in a stars life there is a balance from gravity pulling the star inward and the explosive forces making it so hot. When a star uses up it's fuel it can implode on itself and turn into a black hole. The only reason there aren't way more black holes out there is since the star that is dying has to be at least 9 solar masses bigger than are sun.
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Even though black holes suck through parts of the universe, the universe is inevitably big, and growing so as the universe is being sucked into another dimension by black holes, it is also expanding.
Probably stellar mass black holes
No.
The density of matter just after the big bang is calculated to be sufficient to have spontaneously created black holes; such are called primordial black holes, and searches for their existence are ongoing.
Whether it "needs" them or not, they are there - an inevitable result of a Universe dominated by gravity. Supermassive black holes may have an important role in star formation, but this is still an area of active research.
Black Holes.
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White holes are theoretical objects that are the opposite of black holes. They are believed to be created as a result of the mathematical equations that describe black holes, but there is no observational evidence of their existence. In theory, white holes would expel matter and energy outward, in contrast to black holes which pull matter and energy inward. Their role in the universe, if they exist, is not well understood, but some scientists speculate that they could potentially be connected to the creation of new universes or play a role in the recycling of matter and energy.
There are already black holes within the universe
Even though black holes suck through parts of the universe, the universe is inevitably big, and growing so as the universe is being sucked into another dimension by black holes, it is also expanding.
Black Holes' can 'eat' any type of matter in the Universe.
Probably stellar mass black holes
The universe likely contains millions upon millions of black holes.
No.
Yes.
The black holes may not devour everything since the outward velocity of the matter in the universe may escapethe gravitational pull of the black holes. Stephen Hawkins reckons that even the mass in the black holes would diminish over time, though over trillions and trillions of years.