Scientist Investigates Effects of Small Black Holes on Human Body

Research conducted by Professor Robert Scherrer from Vanderbilt University explores the potential impact of small primordial black holes on the human body. Published in the International Journal of Modern Physics D, the study addresses a unique scientific inquiry: what happens if a primordial black hole were to pass through a human being? This question not only delves into theoretical physics but also enhances our understanding of dark matter.

Primordial black holes are hypothetical entities that may have formed shortly after the Big Bang. Their masses can vary dramatically, ranging from as little as 100,000 times less than a paperclip to over 100,000 times more than the sun. Some researchers propose that these black holes could constitute a significant portion of the universe’s dark matter.

Understanding the Gravitational Effects

In his article, Scherrer investigates the minimum size of a primordial black hole necessary to inflict substantial harm on a human body. By determining these parameters, scientists can gain insights into the characteristics of dark matter, including its mass. This research builds on Scherrer’s earlier collaboration with Jagjit Singh Sidhu and Glenn Starkman from Case Western Reserve University, which examined macroscopic dark matter (MACROs). Their findings indicated that MACROs could cause significant destruction to human tissue.

“I knew that I could carry over some of those calculations to the study of primordial black holes,” Scherrer stated. His interest was sparked not only by recent advancements in black hole research, including new observations of gravitational radiation from black hole mergers but also by a fictional account he encountered in the 1970s, where a character meets their end due to a black hole’s passage.

Potential Human Impact of Black Hole Encounters

Scherrer’s research details two primary gravitational effects a primordial black hole would exert on the human body: supersonic shock waves and tidal gravitational forces. A supersonic shock wave occurs when an object travels faster than the speed of sound, generating a conical disturbance. As a primordial black hole traverses the body, it would create these shock waves, thereby damaging tissues in a manner akin to a bullet wound.

Additionally, the study discusses tidal forces, which refer to the difference in gravitational strength at various points. This effect would stretch and pull human cells apart, particularly affecting the brain’s sensitive cells.

While the findings of this research could assist in determining the mass of primordial black holes, the likelihood of human encounters with such entities is extremely low. Scherrer cautioned, “Primordial black holes are theoretically possible, but they might not even exist. A sufficiently large primordial black hole, comparable to an asteroid or larger, would indeed be lethal. In contrast, a smaller primordial black hole could pass through without causing any noticeable effects.”

The density of these black holes is so low that such incidents are virtually impossible, making them a lesser concern in the grand scheme of threats to human safety.

For more information on this research, refer to: Robert J. Scherrer, Gravitational effects of a small primordial black hole passing through the human body, International Journal of Modern Physics D (2025). DOI: 10.1142/s0218271825410032.