Frozen Universe: Primordial Black Holes' Impact.
Primordial black holes may have formed in the early universe during a violent period of energy and mass shifts. If these black holes were small enough, they would have evaporated completely, releasing their own floods of radiation and matter. This could have led to a stasis in the density of matter and radiation, potentially leaving long-lasting impacts that we could detect even to the present day. The evaporation of primordial black holes also triggers the formation of gravitational waves, which might still be detectable today.