Imagine for a moment: a tiny black hole, barely larger than an atom, passing through your body. This image, worthy of the worst nightmares, is enough to evoke terror. Yet, this question, which seems to belong to the realm of science fiction, has recently been the subject of serious scientific study.
Researchers have delved into this scenario: what would happen if a microscopic black hole encountered a human being?
Primordial black holes: the cosmic dwarfs
"Primordial" black holes are theoretical objects, never observed. If they truly exist, scientists believe they would have formed in the first moments of the Universe, just after the Big Bang. Unlike stellar black holes, which are much more massive, they would be extremely small, some approaching the size of an atom. Their existence remains to be proven, but they generate great interest as they could constitute a part of dark matter.
According to theory, their size and mass could vary widely. In a recent paper, researchers focused on those with a mass comparable to that of an asteroid, ranging from 10¹³ to 10¹⁹ kilograms. Such a mass would imply a diameter of one micrometer.
These primordial black holes, if they exist, would be remnants of the early Universe, witnesses to the extreme conditions that prevailed in the first moments after the Big Bang. Their study could provide us with valuable information about that distant era and the formation of cosmic structures. For now, the study focuses on the impacts such a black hole could have on a human body if it were to pass through it.
Tidal forces: gravity at work
The gravity of a black hole is so intense that nothing (not even light) can escape it. This gravitational force manifests as "tidal forces." A tidal force is the difference in gravity between two parts of an object. If a microscopic black hole passed through a limb, the effect would be comparable to a needle prick. The tidal forces would be too weak to cause significant damage, except... if this force is exerted on a particularly sensitive part of the body.
Indeed, if the black hole were to pass through our head, the consequences could be fatal. Brain cells are very sensitive and could be destroyed instantly. It is important to note that these effects depend on the mass of the black hole. The greater the mass, the more intense the tidal forces. Thus, researchers have calculated that a black hole with the mass of a small asteroid could cause significant, even lethal, damage when passing through certain areas of the human body.
Shock waves: a more serious danger
But tidal forces are not the only risk posed by such a black hole! Its passage through matter would also generate a shock wave, a disturbance that propagates through the surrounding medium. This shock wave is comparable to that produced by an explosion or an object moving at supersonic speed. It carries a large amount of energy and can cause significant damage to biological tissues.
The shock wave produced by a microscopic black hole would be extremely fast and energetic. It could cause cellular tears, internal bleeding, and severe damage to organs. The extent of the damage would be proportional to the mass of the black hole. Researchers have estimated that a black hole with the mass of a small asteroid could generate a shock wave capable of causing fatal damage to a human being. The shock wave would propagate through the body, destroying cells and tissues in its path.
An unlikely encounter
Although the effects of such a scenario are potentially severe, the probability of it occurring is extremely low. The Universe is vast, and primordial black holes (if they exist) are exceedingly rare. It is estimated that it would take billions of years for such an event to occur.
Thus, although the idea of a microscopic black hole passing through our body may seem frightening, it is a highly improbable scenario. We can therefore continue to sleep peacefully.
Article author: Cédric DEPOND