Directly bounds only scenarios in which cosmic-ray-produced black holes would be stopped inside Earth or the Sun (e.g. charged/EM-interacting black holes); the neutral stable case escapes and needs the WD/NS route.
Directly bounds only scenarios in which cosmic-ray-produced black holes would be stopped inside Earth or the Sun (e.g. charged/EM-interacting black holes); the neutral stable case escapes and needs the WD/NS route.