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What’s be super cool is discovering a! asteroid mass primordial black hole in our solar system. No epic interstellar flight needed. It would be super hard to d
by api 1y ago
What’s be super cool is discovering a! asteroid mass primordial black hole in our solar system. No epic interstellar flight needed.
It would be super hard to detect though. We’d have to spot it by gravitational effects or get very lucky and notice lensing. It would emit nothing unless it happened to be nomming on some matter, and even then it’d be so small that the signal would be weak.
- noam_k 1y agoThat would be cool. I read somewhere that a black hole with the mass of the moon will absorb about as much cosmic radiation as it emits Hawking radiation. This is a fine line between "the black hole disappears before we can examine it" and "oops, we got eaten by a black hole".
- MomsAVoxell 1y agoHey, its not like an analog of "Yeah, lets just throw some more mass at the newly-forming black hole in our neighbourhood", said every human that has ever thrown things into the fire, forever ..
- gus_massa 1y agoSorry, but I have to link the "Hole Lotta Trouble" episode of Pocoyo https://www.youtube.com/watch?v=HL_0OL7vZ44 https://www.youtube.com/watch?v=HL_0OL7vZ44
- MomsAVoxell 1y agoYes, you really do.
- api 1y agoBlack holes aren't cosmic vacuum cleaners. They're just super super super compact objects. I've actually posted this a few times: If you suddenly transformed the Moon into a black hole of the same mass, it would continue to orbit the Earth in the same spot. It wouldn't suck up the Earth or anything. The ocean tides would continue as normal under the influence of the black-hole-moon's gravity, which would be the same if it was orbiting at the same distance. You wouldn't see a moon in the sky, but if you focused a good telescope on where it was you'd see gravitational lensing. It would be a little smaller than a BB.
- antonvs 1y agoIf it's in a stable orbit in the solar system, it wouldn't be able to "eat" us. Black holes gravitate exactly the same as any other mass, so it would have the same gravitational effect on Earth as any object if the same mass. What makes black holes special is that you can get much close to their center of mass than you can with normal objects. When you're that close - inside the radius that a normal density object of that mass would have - then you experience gravity at a much higher strength than normal. Put another way, even if our Moon was a black hole with the same mass, very little would change except that it would no longer reflect sunlight. Ocean tides on Earth would remain the same. You wouldn't want to try to land on it though...
- akomtu 1y agoThere was a movie where Moon was a hi-tech 'megastructure' with a white dwarf inside. I wonder if it would be theoretically possible to set up such a mini-dyson sphere around a mini-blackhole.
- api 1y agoIf you set it up at the right radius it would have 1g gravity at the surface, like a little mini-world. It wouldn't be able to hold an atmosphere though, so it would have to have pressurized buildings on it.
- throwaway290 1y agoSomebody write a sci fi with this please, just make sure to describe how trash disposal works
- antonvs 11mo agoIf you're interested in black holes and trash disposal, check out the 1978 short story, "The Nothing Spot": https://vintage.failed-dam.org/nothing.htm https://vintage.failed-dam.org/nothing.htm
- antonvs 11mo ago
- the8472 1y agoWe do not what such a thing anywhere near Earth though. https://arxiv.org/abs/astro-ph/9911309 https://arxiv.org/abs/astro-ph/9911309
- api 1y agoOnly if it evaporates, which it probably wouldn't do for billions of years.
- the8472 1y agoSomething of asteroid mass would be above the CMB equilibrium temperature, thus already be undergoing runaway evaporation. From the paper: "This implies that M must be less than 0.8% of the mass of the Earth"
- NL807 1y ago>It would be super hard to detect though. Would it? I would've thought there is enough dust in the solar system that it would create constant xray emissions. Even if it's faint, it would stick out like a sore thumb on super sensitive xray telescopes.
- TheOtherHobbes 1y agoAn asteroid-mass black hole is around a micron across. It's not going to be nomming on much because the matter distribution inside the solar system isn't that dense. Any tiny black hole born in the big bang would either have evaporated (if Hawking was right...) or would have grown much larger by now. Even a moon-mass black hole (0.1mm) wouldn't be eating much, although its gravitational effects would be much more obvious.
- antonvs 1y agoWe wouldn't have to get lucky if it was on the last stages of evaporating. If it has reached a mass of about a billion kg it would be shining plenty bright to detect, and would only have a few thousand years to live before destroying most life on Earth with gamma radiation.
- terminalshort 1y agoAccording to this calculator https://www.vttoth.com/CMS/physics-notes/311-hawking-radiation-calculator https://www.vttoth.com/CMS/physics-notes/311-hawking-radiati..., the luminosity would only exceed that of the sun for 46.7 nanoseconds, so unless it's much less than 1 AU away we would probably be fine.
- terminalshort 1y agoCould you find it by Hawking radiation?
- pavel_lishin 1y agoI remember reading somewhere that it's possible for such a black hole to get captured by an asteroid (or vice versa, I guess), and happily live inside a rock, slowly orbiting inside the asteroid, sucking up atoms here and there. It would be detectable as an asteroid that's twice as dense as it should be.
- Cthulhu_ 1y agoIf it was asteroid mass, wouldn't it have the same gravitational effect of an asteroid itself? Plus, someone else mentioned it'd be like a micron across, which if my pop-sci understanding of these things is correct, it'd disappear in a poof of hawking radiation.
- api 1y agoIt would have the same mass, and it would be tiny -- like the size of a hydrogen or helium atom. AFAIK an asteroid mass black hole wouldn't evaporate yet since the CMB is still warmer than its Hawking temperature. Very tiny black holes would have evaporated earlier in the universe. A black hole evaporates when its Hawking temperature exceeds the ambient temperature.