Scientists have discovered that tiny, primordial black holes could leave behind microscopic tunnels in rocks and old buildings. These hypothetical objects, created soon after the Big Bang, are thought to be invisible and interact with matter only through gravity.
Researchers at the University at Buffalo and National Dong Hwa University calculated what a tiny black hole would do when it encounters solid objects. They found that one with a mass of 1019 kg could bore a tunnel just 100 nanometers wide through a planet, similar to how a bullet hits an object.
The team suggests that these tunnels could be detected using microscopes and may provide evidence of primordial black holes. However, the probability of finding such signs is extremely low, at 0.000001%.
Source: https://newatlas.com/physics/primordial-black-holes-tiny-tunnels-rocks