In the bouncing universe model, compression before the Big Bang gives birth to relic black holes, gravitational waves, and possibly dark matter. Nonlinear structures (compact objects and dark matter halos) that survive the bounce, if they exceed 90 meters in size, become black holes after expansion — unlike primordial black holes that arose from quantum fluctuations. This mechanism unifies the explanation of dark matter, the gravitational wave background, and early supermassive black holes.
The universe can behave like a spring: compressing to microscopic sizes and then expanding again. In this cycle of contraction and bounce, black holes and dark matter are born. During compression, like in a twisting spiral, densifications arise—clumps of matter and gravitational waves (ripples in spacetime). If a clump is massive enough, it doesn't disintegrate during the bounce, and later galaxies grow from it.
This mechanism solves several cosmic mysteries at once. Dark matter turns out not to be exotic particles, but a swarm of invisible black holes that survived previous cycles. The powerful gravitational waves generated during compression create a background that modern detectors pick up. And supermassive black holes managed to grow even before galaxies gathered around them, because their seeds appeared long before the Big Bang—at the moment of the previous bounce.
🎯 For a clump of matter to survive the bounce, its diameter must be at least 90 meters—the length of a football field.
🎬 A cyclic cosmos, contracting and being reborn, is described in Poul Anderson's novel 'Tau Zero': the characters witness the death and birth of a new world.