Scientist Explores Effects of Small Black Holes on Human Body

A recent study by physicist Robert Scherrer at Vanderbilt University investigates the potential effects of a primordial black hole passing through the human body. Published in the International Journal of Modern Physics D, the research aims to deepen understanding of dark matter, specifically focusing on the gravitational forces that a small black hole could exert on human tissues.

Primordial black holes, theorized to have formed shortly after the Big Bang, vary significantly in mass, ranging from less than that of a paperclip to over 100,000 times the mass of the sun. Some scientists believe these black holes could account for a portion of the universe’s dark matter. Scherrer’s study specifically examines the minimum size required for a primordial black hole to inflict serious harm upon a person.

Understanding the Impacts of Black Holes

In his research, Scherrer builds upon earlier work conducted with colleagues Jagjit Singh Sidhu and Glenn Starkman from Case Western Reserve University. Their previous study explored macroscopic dark matter (MACROs), which are larger particles that could potentially cause significant destruction to the human body. Notably, no fatalities attributed to MACROs have been reported, allowing researchers to set limits on their properties.

“I knew that I could carry over some of those calculations to the study of primordial black holes,” Scherrer stated. His interest was piqued by recent observations of gravitational waves from black hole mergers and the resurgence of public interest in black holes, which he links to a science fiction narrative he encountered in the 1970s.

Scherrer’s article highlights two primary gravitational phenomena caused by a primordial black hole: supersonic shock waves and tidal gravitational forces. When a black hole moves faster than sound, it generates shock waves that can cause severe tissue damage, similar to a bullet’s impact. Additionally, tidal gravitational forces create a differential pull that can stretch and tear human cells, particularly affecting sensitive brain cells.

Should We Be Concerned?

While the findings may assist scientists in determining the mass of primordial black holes as dark matter, Scherrer emphasizes that the likelihood of such an event is minimal. “Primordial black holes are theoretically possible, but they might not even exist,” he remarked. A sufficiently large black hole, comparable to the size of an asteroid, could indeed cause fatal injuries. However, a smaller black hole could pass through the human body without noticeable effects.

The density of primordial black holes is extremely low, making encounters virtually impossible. Scherrer’s research not only addresses the physical implications of black holes but also contributes to the ongoing exploration of dark matter’s properties.

For more details, refer to the study: 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.