What would a small black hole do to the human body? Robert Scherrer aims to answer that
Some people may worry about being bitten by a snake or spider, but have you ever considered what would happen if a small black hole tried to pass through your body?
An article by Professor of Physics Robert Scherrer in the International Journal of Modern Physics D poses and answers that very question. Scherrer set out to find what the gravitational effects would be if a primordial black hole passed through the human body, helping scientists better understand the properties of dark matter.
Primordial black holes are hypothetical black holes that formed in the early universe, possibly within the first second after the Big Bang. They have potential masses ranging from 100,000 times less than a paperclip to 100,000 times more than the Sun. Some researchers think these black holes may make up some, or all, of the universe’s dark matter.
In his article, Scherrer examined the minimum size of a primordial black hole needed to cause significant injury to a person. Knowing this information can then help determine the properties of this type of dark matter, such as its mass.
The article builds upon Scherrer’s previous study, in collaboration with Jagjit Singh Sidhu and Glenn Starkman from Case Western Reserve University, which looked at macroscopic dark matter (MACROs), a broad class of hypothetical dark matter that are large and made of many particles. They found that MACROs would cause sufficient destruction to the human body. Given that no deaths by MACROs have been reported, limits can then be set on the properties of these particles.
“I knew that I could carry over some of those calculations to the study of primordial black holes,” Scherrer said. “Recent observations of gravitational radiation from black hole mergers, as well as new images of black holes, have revived interest in the subject of black holes in general. Plus, I remembered reading a science fiction story back in the 1970s where someone dies from having a black hole pass through them—I wanted to see if this would be possible.”
Scherrer examined two potential gravitational effects caused by a primordial black hole passing through the human body: supersonic shock waves and tidal gravitational forces.
A supersonic shock wave forms when an object moves faster than the speed of sound, and it creates a powerful disturbance in the shape of a cone. When passing through a human body, a primordial black hole would generate these shock waves on its path, destroying human tissues along the way, similar to a bullet entering the body.
The black hole would also produce tidal gravitational forces, or the difference in the strength of gravity between two points. This would create a tensile force, which pulls and stretches materials. This strong force would tear human cells apart, with the most sensitive to these forces being cells in the brain.
While these findings could help scientists determine the mass of primordial black holes as dark matter, do you need to add death by primordial black hole to your list of fears?
“Primordial black holes are theoretically possible, but they might not even exist,” Scherrer said. “A sufficiently large primordial black hole, about the size of an asteroid or larger, would cause serious injury or death if it passed through you. It would behave like a gunshot. A smaller primordial black hole could pass through you, and you wouldn’t even notice it. However, the density of these black holes is so low that such an encounter is essentially never going to happen.”
Read the full research article.