Scientists have discovered what happens when a tiny black hole passes through our body.

If we take a general understanding of black holes, and ask someone interested in astronomy whether a black hole could kill them, the likely answer would be "yes." However, in this case, people envision black holes as incredibly massive objects in space with significant size and mass. At the same time, scientists theorize that the universe is filled with countless tiny primordial black holes, which are roughly the size of an atom or slightly larger, but with a mass comparable to that of an asteroid. Authors of a new study published on the preprint server arXiv investigated what would happen if such a black hole were to pass through a human body. It is believed that these minuscule objects could traverse through the Earth, meaning they could potentially collide with us, as reported by ScienceAlert.

What are primordial black holes?

It is thought that tiny primordial black holes could have formed at the very beginning of the universe's history, and they did not arise from the deaths of massive stars as regular black holes do, simply because stars did not yet exist.

Astronomers have never observed primordial black holes, and it is believed that objects with a mass less than 10 to the power of 12 kg have long since evaporated due to Hawking radiation. However, primordial black holes with a mass greater than 10 to the power of 20 kg, despite their minuscule size, should still exist in the universe and are constantly moving through space, passing through various objects in their path.

Some scientists believe that it is primordial black holes that make up the invisible dark matter holding all galaxies together and playing a crucial role in their development. If this is the case, then such black holes have a mass ranging from 10 to the power of 13 kg to 10 to the power of 19 kg. In other words, their mass is comparable to that of asteroids, even though all of it is contained within a very small size.

Researchers focused on this specific mass range of primordial black holes to determine what impact they might have on a human if they were to collide with their body. In doing so, they examined two effects of black holes: tidal forces and shock waves.

What happens to a person if a tiny black hole collides with them?

Tidal forces arise because the closer you are to a mass, the stronger its gravity is felt. This means that a black hole exerts different gravitational influences as one approaches it. According to scientists, although a primordial black hole may have the mass of an asteroid, its size does not exceed a micrometer or 0.001 mm. This means that the tidal forces of the black hole will only affect a very small area.

The authors of the study state that if a primordial black hole were to pass through a person's body or limbs, it would only result in localized damage to the flesh. In other words, it would not be fatal. The experience of a black hole passing through a human body would likely feel akin to a needle prick.

However, the passage of a primordial black hole through a person's head would be fatal. This would lead to the tidal forces of the black hole tearing brain cells apart. But scientists say this could only happen if the mass of the black hole is at least 10 to the power of 19 kg.

But that's not all; the shock waves from a black hole could also result in a fatal outcome for a person. If a primordial black hole were to penetrate our body, it could create a density wave that would surge through us. Such a shock wave could damage all the cells in the body.

Based on this, scientists suggest that a truly tiny primordial black hole could indeed kill a person.

There is some good news, though. Calculations by scientists indicate that, given the vastness of the universe, even with the potential abundance of tiny black holes, the chances of encountering one are extremely low. Researchers estimate that the probability of any primordial black hole passing through our body is less than one in 10 trillion.