Recent research by physicist Robert Scherrer from Vanderbilt University offers insights into the consequences of a tiny black hole passing through a human body. His findings suggest that, surprisingly, the damage caused by such an event would be relatively minor, especially for black holes below a certain mass. The most significant harm would arise from the shock wave generated as the object moves through flesh, similar to the impact of a bullet.
Tiny Black Holes and Their Mass
Scherrer’s analysis emphasizes that a black hole with a mass of 100 billion tons would inflict less damage than a 0.22-caliber bullet. This analysis aligns with the current scientific interest in primordial black holes, which may contribute to our understanding of dark matter. Primordial black holes are theorized to have formed shortly after the Big Bang due to extreme overdensities in the early universe.
Mass Requirements for Damage
To better understand the implications, Scherrer calculated the minimum mass required for a primordial black hole to cause significant injury. That threshold is approximately 140 quadrillion grams, or 140 billion metric tons. For context, this is about seven times heavier than the asteroid Toutatis.
- Schwarzschild diameter of a black hole at this mass is 0.4 picometers.
- Comparatively, a hydrogen atom has a diameter of about 106 picometers.
The Effects of Velocity and Tidal Forces
If a tiny black hole travels at a velocity of around 200 kilometers (124 miles) per second, it would minimally interact with surrounding tissues. However, this speed is significantly faster than sound in air, resulting in a supersonic shock that could damage flesh similar to a bullet wound.
Moreover, black holes exert gravitational forces that can affect objects nearby. These forces are not uniformly distributed, creating what is termed a tidal force. This effect stretches and potentially tears objects apart in a phenomenon known as spaghettification.
Minimum Mass for Tidal Damage
For a tidal force from a primordial black hole to inflict serious damage to sensitive human tissues, including the brain, the black hole must have a mass of at least 7 quintillion grams, or 7 trillion metric tons. This is comparable to the asteroid Iris.
Rarity of Black Hole Encounters
Despite the theoretical risks, the actual likelihood of such an encounter remains extremely low. Scherrer estimates that the probability of a human colliding with a primordial black hole is about once every quintillion years. This threshold far exceeds the current age of the universe, which is about 13.8 billion years.
- Primordial black holes may not even exist.
- If they do, their density is so low that such encounters are virtually impossible.
In conclusion, while large primordial black holes could pose serious risks, smaller ones might pass unnoticed. Scherrer advises that, despite the fascinating implications of these black holes, the risks are minimal, allowing for a peaceful night’s sleep.
The full findings of this study are published in the International Journal of Modern Physics D.
