Indeed, any black hole with a mass greater than about 0.75% of the Earth’s mass is colder than the cosmic background, and thus its mass increases for now. As the universe expands and cools, however, eventually the black hole may begin to lose mass-energy through Hawking radiation.
Size isn’t actually the main factor, mass is.
A teaspoon of what neutron stars are made of weighs as much as Mt. Everest.
Its the mass thats important, and apparently the threshold for an actually stable black hole is 0.75% the mass of Earth, 4.48 x 10²² kg … or, roughly 2/3 the mass of the Moon.
(The Moon’s mass is roughly 1/81th that of Earth’s. It ks far, far less dense.)
So… basically 0 chance in our natural life times we’ll figure out how to convert the Moon into a blackhole, lol.
EDIT:
There… could theoretically be a wandering black hole of aporoximately that mass… but even if it entered our solar system, chances are it would just get thrown out, deflected by Jupiter and the Sun, and it would only maybe eat some ice in the Kuiper belt, dust and maybe very small asteroids in the asteroid belt if it somehow made it past Jupiter.
Black holes don’t have infinite gravitational vaccuum power that extends infinitely, because they do not have infinite mass.
if they did, the occurence of one would instantly eat the entire universe at the speed of gravity, which is the speed of light.
They have as much gravity as their mass says they should, and they obey the same orbital dynamics as every other massive celestial body.
https://www.vttoth.com/CMS/physics-notes/311-hawking-radiation-calculator
Size isn’t actually the main factor, mass is.
A teaspoon of what neutron stars are made of weighs as much as Mt. Everest.
Its the mass thats important, and apparently the threshold for an actually stable black hole is 0.75% the mass of Earth, 4.48 x 10²² kg … or, roughly 2/3 the mass of the Moon.
(The Moon’s mass is roughly 1/81th that of Earth’s. It ks far, far less dense.)
So… basically 0 chance in our natural life times we’ll figure out how to convert the Moon into a blackhole, lol.
EDIT:
There… could theoretically be a wandering black hole of aporoximately that mass… but even if it entered our solar system, chances are it would just get thrown out, deflected by Jupiter and the Sun, and it would only maybe eat some ice in the Kuiper belt, dust and maybe very small asteroids in the asteroid belt if it somehow made it past Jupiter.
Black holes don’t have infinite gravitational vaccuum power that extends infinitely, because they do not have infinite mass.
if they did, the occurence of one would instantly eat the entire universe at the speed of gravity, which is the speed of light.
They have as much gravity as their mass says they should, and they obey the same orbital dynamics as every other massive celestial body.
We’re fucked if a black hole hits us, but we’re fucked if anything with the same mass hits us
That is fascinating. Thank you.