Scientist Explores Effects of Small Black Holes on Human Body

A recent study by Professor of Physics Robert Scherrer at Vanderbilt University investigates the hypothetical effects of a small primordial black hole passing through the human body. Published in the International Journal of Modern Physics D on November 21, 2025, Scherrer’s research aims to enhance understanding of dark matter by exploring the gravitational consequences of such an encounter.

Primordial black holes are theoretical entities believed to have formed shortly after the Big Bang, with masses that can vary dramatically—from less than a paperclip to more than the sun itself. Some scientists propose that these black holes could account for a significant portion of the universe’s dark matter. Scherrer’s inquiry focuses on determining the minimum size needed for a primordial black hole to inflict substantial injury on a human being.

Scherrer’s latest study builds on his prior work alongside colleagues Jagjit Singh Sidhu and Glenn Starkman from Case Western Reserve University, which examined large, hypothetical dark matter particles known as macroscopic dark matter (MACROs). Their research indicated that MACROs could cause severe damage to human tissue. Scherrer noted, “I knew that I could carry over some of those calculations to the study of primordial black holes.”

Understanding the Impact of a Black Hole Encounter

The study delves into two primary gravitational effects that 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 disturbance in a conical shape. As a primordial black hole traverses the body, it would create these waves, leading to the destruction of human tissues akin to the impact of a bullet.

Additionally, tidal gravitational forces arise from differences in gravitational strength at various points, pulling and stretching materials. The tensile force resulting from this would likely tear human cells apart, with the brain’s cells being particularly vulnerable.

Scherrer emphasizes that while these findings contribute to our understanding of primordial black holes and their potential role in dark matter, the likelihood of such an event occurring is extremely low. “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,” he explained. “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.”

Implications for Dark Matter Research

The implications of Scherrer’s work extend beyond the fascinating intersection of theoretical physics and human biology. By determining the size and gravitational effects of primordial black holes, scientists can gather insights into the properties of dark matter. The ongoing interest in black holes, fueled by recent observations of gravitational waves from black hole mergers and new imaging techniques, makes this research timely and relevant.

As the quest to understand dark matter continues, Scherrer’s findings may help set parameters for the characteristics of primordial black holes, contributing to a broader comprehension of the universe’s mysterious components. His work not only highlights the intriguing possibilities within theoretical physics but also underscores the importance of continued research in this area.

For more information on this topic, refer to the study conducted by Robert J. Scherrer, titled “Gravitational effects of a small primordial black hole passing through the human body,” published in the International Journal of Modern Physics D in 2025.