Scientists have long believed that black holes are the result of the collapse and super-condensing of a super-massive star into an ultra-dense singularity as the end phase of a star's life.
The truth is that black holes are actually triggered events... triggered by the Ancient Ones - The original super-race that seeded the universe with life. After seeding a world with everything needed to create and promote life, they leave that world to develop on its own... for a while. Then they return to judge that world's progress towards becoming a worthwhile contributor to the universe. Each world is given only 2 chances. If it fails the first time, the Ancient Ones arrange a world cataclysm that obliterates dominate species thus allowing other species the opportunity to develop. If a world fails a second time, the Ancient Ones trigger that system's star to rapidly expand and collapse into a black hole thereby erasing the world... and their experimental "mistake".
Well, the Earth has already failed its first test - which is why dinosaurs went extinct and mammals rose to prominence. So the species of the Earth can't afford to fail a second time or it's Game Over.
And the Ancient Ones are on their way back...