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Something about your comment triggered a primal fear in me of tiny, immortal 9mm bullets of non-existence fired randomly in space at all directions until I reme
by rolleiflex 7y ago
Something about your comment triggered a primal fear in me of tiny, immortal 9mm bullets of non-existence fired randomly in space at all directions until I remembered an earth-mass black hole, while about a centime wide, it's still has a full gravity field the size of Earth's. If one's coming our way, we probably can't do much, but we'll see it coming.
- sliken 7y agoSeems unlikely. It emits close to nothing, it's temperature is less than 2.7 kelvin, and we'd have to be spectacularly lucky to see a micro lensing event with such a small mass. Hell we barely notice when a several km comet enters the solar system and I've read about fairly large asteroids getting closer to the earth than the moon before being noticed. We are going to notice a 9mm black hole? Maybe if it punctured Jupiter first.
- xaedes 7y agothe fast moving mass of earth will distort orbits via gravity. that will be noticed
- sliken 7y agoIf you removed the earth, except for the moon the solar system would change very little. Sure if the earth came between Jupiter and it's moons there might be some chaos, but the likelyhood of that is minimal. Even if it did happen we would notice, but the earth massed black hole would be very unlikely to make it into the inner solar system at that point. The earth is a minor gravitational force in the solar system, most likely the effects would take significant time to notice... well after the nearest approach. Small gravitational tugs take many samples and significant time to notice. For example the outer solar system still doesn't add up... and we have no idea why.
- sitkack 7y agoThis sounds like a super fun simulation to run. Do you have recommendations on simulation software? I found these in a quick search. I have a couple 64 core machines available. https://wwwmpa.mpa-garching.mpg.de/gadget/ https://wwwmpa.mpa-garching.mpg.de/gadget/ https://rebound.readthedocs.io/en/latest/ https://rebound.readthedocs.io/en/latest/ http://www.tapir.caltech.edu/~phopkins/Site/GIZMO.html http://www.tapir.caltech.edu/~phopkins/Site/GIZMO.html
- T-hawk 7y agoThe outer solar system is pretty well accounted for. For many years we thought it wasn't, and kept hunting for another (sufficiently-massive so not Pluto) planet beyond Neptune. The discrepancy turned out to be an overestimation of Neptune's mass, which was resolved by Voyager and subsequent observations. We've now ruled out anything of Neptune's mass or greater existing out to at least 100 AU and likely several multiples of that.
- sliken 7y agoAh, thanks for the update.
- deeviant 7y agoProbably not. It would be something that would likely have to be observed over multiple complete orbital cycles and basically somebody basically run into it by accident. By which, of course, the earth in this hypothetical, would be long dead.
- marcosdumay 7y agoA black hole with the mass of Earth out of sync with it surroundings will surely emit a lot on UV and X-rays. Space isn't completely empty, and the stuff on its path won't orbite it. We would detect one entering our Solar System.
- dragonelite 7y agoThis comments, reminds me of the dual vector attack in the Death's End novel of Remembrance of Earth's Past trilogy from the writer Liu Cixin. Its was a small object fired at the solar system by a highly advance race, where 3d space was projected into a 2d plane so the whole solar system was destroyed.
- thatcherc 7y agoPretty big plot point! Don't want to give away the story
- est 7y ago> immortal 9mm bullets of non-existence fired randomly in space at all directions until I remembered an earth-mass black hole, while about a centime wide Now imagine what a strong force an electron could provide :D
- MiroF 7y agoHow do you suppose we would see it coming?
- wtallis 7y agoIf it's not moving quickly, we would notice its gravitational interaction with the well-known dynamics of the various large objects already in our solar system. A 9mm black hole's gravitational influence would be fairly subtle though compared to a multiple Earth-mass black hole; the bowling ball sized black hole mentioned in the paper as an upper bound is not the kind of thing that could wander into the inner solar system unnoticed.
- lumberingjack 7y agoI read a fiction book about a tiny black hole getting caught in the planets gravity well then falling threw Earth back and forth just fucking stuff up every time. Scary stuff.
- Spare_account 7y agoDo you remember its name?
- nicolaslegland 7y agoSounds familiar, could that be the Big Mistake in Hyperion or the Hole Man short story? https://en.wikipedia.org/wiki/The_Hole_Man https://en.wikipedia.org/wiki/The_Hole_Man https://hyperioncantos.fandom.com/wiki/Big_Mistake https://hyperioncantos.fandom.com/wiki/Big_Mistake
- nullc 7y agoMaybe ... Earth by Brin Hyperion Cantos by Simmons Ilium by Simmons Doomsday Effect by Thomas Wren If I thought for a few more minutes I could probably come up with a half dozen examples (or expanded the definition to include eating the moon or mars, or included ones where it would be a massive spoiler)... A gravitationally captured/trapped black hole eating earth is relatively common plot device in science fiction.
- pmontra 7y agoPlenty of titles at https://en.wikipedia.org/wiki/Black_holes_in_fiction https://en.wikipedia.org/wiki/Black_holes_in_fiction
- petjuh 7y agoIt would go right through Earth. There might be pretty big explosions though as it feeds on earth's mass.
- deleted 7y ago[deleted]
- ryandvm 7y agoTotal (unqualified) spitballing, but wouldn't a black hole "bullet" that hit the Earth experience effectively 0 frictional losses? By definition it won't be pushing stuff out of the way, so it seems like an inbound black hole would punch right through the Earth. Local gravity is probably going to be quite nasty during the transit, but beyond that, it seems like a fairly survivable event.
- nine_k 7y agoWon't it pull some of the matter it passes through under the event horizon? The extremely curved spacetime will likely turn rock to dust in near vicinity. Then, as the mass grows, so would the gravitational pull, while the speed relative to the planet being punctured would lower due to conservation of momentum. If the tiny bullet-class black hole makes it through a planet, it could gain significant additional mass, and leave quite an exit wound.
- neuronic 7y agoIf a random PBH of 9mm traveled at near light speed through Earth, would it even pull anything into the event horizon that is not within close range of that 9mm diameter? For example, it travels through Earth and then leaves a 9mm hole throughout the planet.
- Enginerrrd 7y agoNo it wouldn't, but I'm thinking it would be able to transfer some kinetic energy to the earth which would be a very very bad thing.
- perl4ever 7y agoI'm not good at physics, but it seems to me if this 9mm object had the mass of earth, then at a distance of about 6400 km it would exert 1G, and at minimal distance, it would exert about a zillion Gs. So even assuming it didn't pull in matter per se, the gravity and tidal forces ought to destroy earth about as effectively as colliding with a regular earth sized planet.
- 7y ago
- rfeBZiMH 7y agoYou should read Seveneves by Neal Stephenson. The plot of that book follows the events after a primordial black hole streaks through the Moon, causing it to implode. It's packed with detail, but interesting for anyone interested in space and engineering.
- jrs235 7y agoThis whole topic and discussion makes me think about "The Nothing" that rips apart the world in the movie The Neverending Story. I had nightmares from the movie and The Nothing for weeks after watching the movie when I was around ten years old. 1984 might really be approaching, not the book, but The Neverending Story which was released then.
- knzhou 7y agoIn some exotic models, dark matter acts like bullets that are always flying through you, but with a tiny chance could interact and leave something basically like a bullet wound: https://arxiv.org/abs/1907.06674 https://arxiv.org/abs/1907.06674