One day, you're strolling the street, feeling cheerful, when suddenly whoosh! A small object streaks past you like a meteor. You didn't even have time to blink, and couldn't see what it was, but in that split second, your body felt an indescribable force, as if an invisible hand had pushed you hard. You had no time to react, and all left in your mind was one question: what just happened? Don't panic, this isn't a scene from a sci-fi movie; it's the real topic of this article the effects of a micro black hole passing through your body. 

You can imagine a black hole as the universe's ultimate vacuum cleaner, with gravity so strong that even light can't escape. It's like a bottomless whirlpool, sucking everything in around it. This "whirlpool" not only devours stars and planets but even light can't escape. Black holes are regarded as one of the universe's most enigmatic and hazardous objects as a result. You might ask since black holes are so powerful, if one suddenly appeared on Earth, wouldn't everything be sucked in? Yes, the gravity of black holes is incredibly strong, but luckily, they don't appear next to us all the time. Especially micro black holes, which, while extremely small, still possess immense gravity. Now, imagine a micro black hole appearing on Earth. With a mass and size that are very small. For example, it could have a mass of a few trillion kilograms, close to the mass of a small asteroid. Sounds tiny, right? But in reality, the gravity of such micro black holes is still powerful enough to affect the human body. The diameter of this black hole might be as small as a millionth of a meter, even thinner than a strand of hair. It's so tiny that we would hardly notice its presence. However, its gravity is strong enough to tear everything apart.

Imagine that you're standing next to the black hole. Your body would be like a floating object in the sea. The waves keep crashing against you, and the water exerts different amounts of force at different points. Under the black hole's gravity, this force becomes extremely powerful and could even tear apart parts of you. The closer the black hole gets to your body, the stronger its gravity becomes, and it will exert different pulling forces on various parts of your body. You could think of it like a huge, invisible hand, constantly pulling your body in different directions. The effects of this pull are not uniform. If the black hole passes through your limbs or abdomen, although you will feel intense discomfort and pain, it won't be immediately fatal. It would be like a very fine needle piercing your skin, potentially causing localized damage. But if the black hole passes through your head, the consequences would be much worse. Your brain is extremely fragile, and the strong tidal forces created by the black hole could tear apart brain cells, potentially fatal. In addition to tidal forces, a micro black hole passing through the body would also release an extremely powerful shockwave. You can think of this shockwave as the ripples on the water’s surface when you drop a large stone into a pond. Each ripple spreads outward, and the closer you are to the centre, the stronger the ripple. In the case of a black hole, this shockwave is so powerful that it can penetrate every inch of your skin, like a violent shockwave, destroying everything inside your body. This shockwave doesn't just affect your body through gravitational forces; it can also create a "density wave"— it's like a massive surge of energy suddenly coursing through your body. This energy wave could travel to various parts of your body.

Although the existence of micro black holes sounds like something out of a sci-fi story, they don't pose a real threat. Their gravity is strong enough to cause tidal forces and shockwaves, but due to their extremely low probability of existence, we're rarely going to encounter such a situation. Black holes are not celestial objects that appear near Earth on a whim. There are very few miniature black holes in the cosmos, even in its vastness. Furthermore, it is really challenging to find them. Even if they do exist, the chance of one passing through your body is almost zero-you are very unlikely to encounter such a situation, with a probability of maybe one in a trillion.

（Writer：Matti）