Primordial black holes (PBHs) are theorized to have been created in great numbers in the radiation era shortly after the Big Bang. Due to a formation process not related to stellar collapse, they could have had essentially any range of masses: from an atomic nucleus to thousands of solar masses.
If PBHs were really abundant, one must have collided with a star by now. Let’s say a wandering PBH with 1 Earth mass collides with the Sun at a relatively low velocity: it would oscillate through the Sun and eventually settle at the core. It would eat the Sun’s fusing mass at the core without contributing anything to energy production. (The pressure at the Sun’s core would essentially force-feed the PBH.)
As the PBH feeds on the superdense matter in the core, the Sun would contract and brighten in an effort to maintain hydrostatic equilibrium. A vicious cycle would follow as the PBH grows and grows; the Sun would get brighter and brighter until it… explodes as a supernova? collapses into a BH itself?
But there is no observational evidence for any star meeting this fate. No supernova has ever been observed in low-mass Sun-like stars. Nor has any Sun-like star been observed collapsing into a BH.
Not one instance in the all the galaxies surveyed so far.
Does this not essentially rule out the existence of PBHs?