What if there was a black hole in your pocket?
Why Worldbuilding Stack Exchange recommends it
Worldbuilding Stack Exchange users link it as a quick, sourced reference when answering or asking about small black holes, crater-making events and catastrophic space threats.
Recommended by 1 people across 1 different months, 2016 to 2021.
What it is
A short animated explainer from Kurzgesagt that works through what would happen if a black hole the size of a coin appeared in your pocket. It compares a coin-mass black hole, which evaporates almost instantly via Hawking radiation, with a coin-sized one, which would have roughly the mass of the Earth and wreck the planet.
What people said
Recommends Zane Dufour · 2021-04 · Worldbuilding Stack Exchange · on “What do my wizards drop on towns to turn them into craters?”
Dang, I was going to do a write up about this, but you've answered it much better than I can. One thing I can add is that kurzegsagt has a great bite-sized video on this topic [this video] .
Cites valepu · 2016-01 · Worldbuilding Stack Exchange · on “Catastrophic event from space/earth that humanity are able to see it coming”
if we go for the less classic solutions (meteorites, comets, asteroids and so on) there isn't much we can actually predict. Stuff coming from the sun usually comes without warning and it takes very little (compared to astronomic times) to reach earth. Other things are: 1) not very visible until it's too late (Aliens? ) 2) Visible enough that we can know it in advance (Comets or even incoming planets) 3) Too sudden (Solar Flares) 4) The information of the event comes with the event itself (Gamma Ray Bursts, which travel at the speed of light so you get a visual of the event at the same time of the damage being done) An idea could be a Rogue Black Hole (yes, they are a thing): a black hole wan
Cites Harrenhal · 2017-10 · Worldbuilding Stack Exchange · on “Would it be possible to have a small black hole dissipate as it 'sinks' into the earth?”
I recently watched this Kurzgesagt video [this video] exploring the question of what would happen if you had a black hole the size of a coin. To summarize the video: A black hole with the MASS of a coin would have a radius 10^-30m and would decay by Hawking Radiation in 10^-23 seconds with the explosive force of 450 terajoules. A black hole with the SIZE of a coin would have a mass comparable to Earth and become a dominant gravitational force in the Earth-moon system, passing into the Earth as the Earth begins to orbit it. It wouldn't 'fall' directly inwards, but slightly and then carve out rings of material as the Earth orbits around their shared center of gravity. (2:04 in video). Earth would l