In the vast universe, Black Holes are perhaps the most terrifying “cosmic predators” we’ve ever known. With their immense gravitational pull, no material, not even light, can escape a Black Hole once it crosses the event horizon.
The True Power of a Black Hole
In theory, we can create a Black Hole by compressing a sufficient amount of mass into a small enough space to warp spacetime. For instance, to turn Mount Everest into a Black Hole, you would have to compress the entire mountain to the size of just a few atoms. Although this Black Hole may sound tiny in this scenario, one thing is for sure: you wouldn’t want to get too close to it.
Estimates suggest that within a radius of 10 meters around a Black Hole the size of an atomic nucleus, its gravitational force equals that on the surface of Earth. This should give you some idea of the power of this cosmic monster.
Moving to a more imaginable scale, what havoc would a coin-sized Black Hole wreak if it were to approach our planet?
The question posed above actually has two answers, depending on how we define the size: by mass or by diameter.
Hypothesis I: If the Black Hole has a diameter equivalent to a coin
As mentioned, a Black Hole the size of an atomic nucleus requires a mass equivalent to Mount Everest. Therefore, in the case of a Black Hole with a diameter equivalent to a coin, its mass would approximate that of Earth. In terms of power, the gravitational force of this “coin-sized” Black Hole would be one billion billion times that of our Earth.
If this Black Hole were to approach Earth too closely (beyond the Roche limit: the closest distance two celestial bodies can get), the consequences would be truly catastrophic!
Firstly, it’s important to note that the blue planet would not simply be instantly devoured and disappear! What would actually happen is that Earth would be influenced by the massive gravitational pull of the Black Hole and start orbiting around it, rather than the Sun. During this time, different parts of the planet would be gradually pulled apart and drawn toward the Black Hole. The cosmic predator’s meal would be slightly delayed due to the Earth’s rotational motion. Nevertheless, ultimate destruction would still ensue. Eventually, the remaining materials of what used to be Earth would be transformed into a molten and swirling disk around the Black Hole.
Surprisingly, the Moon would be almost unaffected, except for a more elliptical orbit.
Hypothesis II: If the Black Hole has a mass equivalent to a coin
A typical coin weighs less than 5 grams. Therefore, compressing 5 grams of matter into a Black Hole would result in a very tiny cosmic predator. Tiny to the extent that the size difference between this Black Hole and an atom is similar to the difference between an atom and the Sun. However, its power should not be underestimated!
It’s important to know that Black Holes continuously evaporate any matter they have or capture back into the universe, a process known as “Hawking radiation.” This evaporation reduces the mass and energy of the Black Hole. Consequently, no matter how many planets it devours, a Black Hole cannot increase its mass. Over time, Black Holes shrink and eventually disappear. Notably, the evaporation in tiny Black Holes is much more vigorous than in larger ones.
Returning to the coin-sized Black Hole, due to its extremely small size, the evaporation occurs so rapidly that it results in a significant explosion, estimated to be equivalent to 100,000 tons of TNT. This explosion wouldn’t shatter Earth, but it would certainly wipe out everything within its affected range!