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What If Planet 9 Is a Primordial Black Hole?

• sidcool 7y ago
  That would be a bit scary. Even a little wiggle in the orbit of such a body could spell devastation.
  • c3534l 7y ago
    Not really. A black hole isn't any more dangerous than any other object with the same mass. A black hole with the mass of Earth, for instance, would behave exactly as Earth does, except when an object collides with it, it continues on down into the center where it would hit Earth's crust if it were a planet.
    • fooker 7y ago
      >continues on down into the center You'll get a Nobel prize or two if you could prove that..
      • saagarjha 7y ago
        Not really, it’s pretty simple that an object that dense would just pass through the ground.
        • mlnj 7y ago
          The ground or the entire planet cannot remain in its current form anywhere near a black hole. There would be no ground for the black hole to sink to. Besides wouldn't the 'ground' gravitate towards the black hole than the other way around?
          • zaarn 7y ago
            For the black hole the ground is merely more dense vacuum, the ground has barely enough time to move if it comes in at interplanetary velocities (50km/s+), so by the time the ground will begin to react to the intense gravity, the black hole will have passed through with the force of a few hundred nuclear explosions.
            • sliken 7y ago
              At 6000 km away the gravity at the nearest surface of earth is zero. 1 minute (at 50km/sec) later it would be 3000 km the acceleration 4.5G or so. 1.5 minutes later it would 1500 km away the acceleration would be 17G or higher. 2 minutes later it would be on the surface, and everything ripped up (including buildings, soil, bedrock, crust, and the magma below would go from being accelerated up at incredible velocities to an even more intense acceleration down. Over that 2 minutes the black hole is going to chew the hell out of the earth for 1000s of km in all directions and that's just the start of the fun. As it hits the surface everything within 1000km will be experiencing 40G. The pressure waves will go from negative (as the black hole pulls the atmosphere away from the earth) to a HUGE over pressure as magma, bedrock, and water get slammed back down into the earth at 40G. Said over pressure wave of intense heat and pressure will expand outward from the point of impact and create problems world wide. Worse on the opposite side it will just take a large chunk with it (approximately the volume of which the black hole has significantly more than 1G of gravity) which could easily take a continent with it, or say most of the pacific ocean. I could see ocean levels and air pressure lowering significantly. After all why would the air stick around a 1G planet instead of a more than 1G black hole? The area from which the air is removed is likely to be somewhere around 12,000 km wide (the area of which the black hole applies more than 1G). So I'm not sure I believe the "barely enough time to move" thing when for minutes the accelerations will be crazy.
        • fooker 7y ago
          What do you think the density of a black hole is? :)
          • cthalupa 7y ago
            Almost certainly not actually infinite in reality :) We treat it that way because, despite it showing that our model of physics is breaking down at that point, it works really well for most real purposes. But look at string theory, loop quantum gravity, etc., and you will find plenty of the variants within those umbrellas do not have a singularity at the heart of black holes.
        • sliken 7y ago
          Not to mention that anything with 9mm would accelerate at the speed of light to the singularity. So while moving through the earth it wouldn't meet any resistance at all.
    • hailk 7y ago
      A layman here. Wouldn't a Black Hole with a mass equal to Earth's be significantly smaller than Earth? Won't the Gravitational range (Schwarzschild radius?) be significantly less than Earth's?
      • tempay 7y ago
        No at a distance it would be exactly the same. You would only start to notice the difference gravitationally once you get to be around 1 earth radius away.
      • deleted 7y ago
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      • cthalupa 7y ago
        The Schwarzschild radius is determined by the mass of the object, not the volume. Radius = (2 * Gravitational Constant * Mass)/(Speed of Light^2)
        • ttul 7y ago
          In other words, 9mm
          • kijin 7y ago
            The entire mass of Earth, compressed down to the size of a bullet. That's actually a very vivid illustration, unlike most of the other large numbers that get thrown around in astronomy.
            • everyone 7y ago
              Its actually compressed down to a point. A singularity. The 9mm is just the radius from the point from which nothing can return.
              • chopin 7y ago
                To be fair, we don't know what is behind those 9mm. Einstein's equations predict a singularity but afaik there is consensus that those don't hold there.
    • sliken 7y ago
      If a black hole has the mass of the earth it's Schwarzschild radius would be about 9mm. If it was disturbed from an orbit well past pluto it would have quite a velocity when it hit earth. The good news is it would pass effortlessly through the earth and not go to the earth's core and stay there. After all where is the resistance going to come from? Now if the blackhole was brought to rest at the earth surface it wouldn't reach escape velocity (11.2 km/sec), but anything coming from way past pluto would likely have a much larger velocity. The bad news is that having an earth skewer the earth at high speed is going to cause some pretty crazy gravitational interactions. Also some of the matter falling into the black hole from earth would be consumed, but some of it would radiated out, no idea if that would be worse than the physical disruptions or not.
      • ehsanu1 7y ago
        The collision case is screaming for a "What If"-style exposition, as in https://what-if.xkcd.com/ https://what-if.xkcd.com/
      • IvyMike 7y ago
        To paraphrase Neal Stephenson, "The earth blew up without warning and for no apparent reason."
      • Zardoz84 7y ago
        and wildy change Earth orbit
      • KiwiJohnno 7y ago
        >crazy gravitational interactions Thats putting it very mildly. Its actually quite an interesting thought exercise - As this black hole approached earth its gravity would counteract earth's gravity, meaning everything near where it "touched down" would experience near zero-g as it approached. The opposite side of the earth would experience greatly increased gravitational pull... Then while the black hole was inside the earth, everything would be experiencing close to 2G, then zero G for a bit for the poor souls on the side of the earth where it exited. Because of the fantastic amount of momentum it would have, and it would certainly be travelling at well over earth escape velocity I would expect it would travel straight through earth and keep going, not even coming close to stopping inside earth. The affects on earth would be very... bad. I'd imagine it would trigger devastating global earthquakes, as well as epic rock slides from the changing gravitational forces. Not to mention the tsunamis from the oceans sloshing around like water in a giant bath, as well as all the rockslides both above and below water. It would be a mess. Assuming this object would be travelling at 100km/sec, and the gravity would maybe begin to badly affect us when it was 50,000 km out from the surface of the earth (?) then it would take about 16 hours to travel from this distance, impact the earth and then reach this distance out the other side. I'm not sure how much energy would be released by the matter being consumed by the black hole - It might not be very much, after all its total gravitational pull wouldn't be very high, but would be travelling at probably at least 50+ km/second - certainly more than 11km/sec (earth escape velocity) The matter in front of the black hole might simply be swallowed up without much fuss, or if there is any "resistance" to this matter falling down past the event horizon I'd imagine it would be like a continuous series of nuclear bombs going off as matter was flash heated to the point of spontaneous nuclear fusion before it passed the event horizon. The one good point to note in all of this is it would be extraordinarily difficult to disturb this object from its object so it fell into the inner solar system. After all, it has the same mass as earth, and we don't have to be worried about random stuff disturbing earth's orbit.
    • mongol 7y ago
      I think a black hole with earth mass would be much more dangerous than earth itself.
      • spacehome 7y ago
        Humans might be plenty dangerous to the rest of the galaxy. It remains to be seen.
    • stevula 7y ago
      To the parent comment’s point though, would that really be any worse than an earth-sized planet colliding with the earth? If anything it sounds like it might be less destructive.
    • deleted 7y ago
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  • dreamcompiler 7y ago
    Nope. Replace the Earth's Moon with a black hole of the same mass. Nothing bad would happen except our nights would be darker. Our tides wouldn't even change.
    • InterestBazinga 7y ago
      Are there any sources on this? Would love to read more on this theoretical scenario.
      • RandallBrown 7y ago
        Not really the same scenario, but Neal Stephenson's Seveneves is a fictional account of what might happen if the moon suddenly exploded.
    • chrismorgan 7y ago
      The question “What would happen if the Moon were replaced with an equivalently-massed black hole? If it's possible, what would a lunar ("holar"?) eclipse look like?” is answered at https://what-if.xkcd.com/129/ https://what-if.xkcd.com/129/. It starts with “ ‘Not much’ and ‘not much.’ ”
      • dreamcompiler 7y ago
        I have that book and it's wonderful. I was probably plagiarizing unconsciously.
    • monkeycantype 7y ago
      Sure, fine for you and me. Might, have been a problem for Buzz Aldrin though.
      • dehrmann 7y ago
        Michael Collins, it's your time to shine.
  • SiempreViernes 7y ago
    Of more concern is the fact that they suppose this primordial black hole was captured from a population of micro black holes that just wanders around out there. One of those hitting closer in in the solar system could be pretty upsetting.
    • dreamcompiler 7y ago
      Only because black holes are hard to see. A black hole has to obey Newton's laws as much as an asteroid does. If either is on a collision course with Earth, we're toast. Any black hole not on a collision course with Earth is merely an interesting curiosity.
      • mlyle 7y ago
        An 5x Earth mass object doesn't need to impact Earth to create a bad time on Earth. It just has to get moderately close.
        • dreamcompiler 7y ago
          Very true. And it doesn't matter if it's black or reflective, except we're sure to see it coming if it's reflective.
      • ltbarcly3 7y ago
        If the black hole is moving very rapidly, and it passes through the center of mass of the Earth, and it is moving parallel to the Earth's motion around the Sun, well it's 'less bad', and the path being parallel becomes less important the faster the black hole is going. The gravitational disruption will be equal in intensity to a slow moving black hole, and huge near the path of the black hole (something about 100m from the path would experience an acceleration of about 4 billion times Earth's surface gravity, but only for a very short time, something 1000km from the path would max out at about 40x), but things far from the black hole's path will only experience a few G of net additional acceleration for an extremely short time. The change in the Earth's orbit would be minimized. The amount of energy transferred between the black hole and the earth from the actual collision would be negligible. In fact by far the greatest harm would come from an off-center collision, since that is what would determine how much momentum would be transferred, and that is what would cause our orbit to change. However, that 4 billion g acceleration is a problem even if it is only for a very short time. If the black hole is going at .999999999c, which is far more than we can hope for, something withing about 100m it's path would be accelerated due to the gravity of the black hole so much that it ends up moving at hundreds of thousands of miles per hour, and stuff within a few dozen meters becomes relativistic. Even ignoring the stuff very close to the path of the black hole, the stuff at hundreds of meters from the path would release an epic amount of kinetic energy. My envelope isn't large enough to see just how large, but certainly enough to leave a melted/vaporized tube at least a few hundred meters across all the way through the earth, and this is a gross underestimate.
• dreamcompiler 7y ago
  Interesting hypothesis. Primordial black holes -- if they exist -- have a tendency to be very small, and very small black holes evaporate extremely quickly. The smallest ones couldn't have survived to the present day. An Earth-mass black hole is big enough to have survived until now, but I was under the impression PBHs that big were posited to be very rare.
  • subroutine 7y ago
    They are looking at several objects between approx. 1-20 Earth-masses (presumably they were bigger during primordial creation; this is their size, now, after 13 billion years of evaporation).
    • ajross 7y ago
      Earth-mass black holes have surface temperatures well under that of the cosmic background radiation and will not have evaporated, they'd have been literally accreting mass just from the background. You need to get down to the billion-ish tons range to find black holes that can have appreciably evaporated over the life of the universe.
    • DuskStar 7y ago
      The bigger the black hole, the slower it evaporates. By the time you get up into planetary sizes they basically don't change mass on the time scale of stars. (From this wonderful calculator [0], a black hole with a mass of 6.0x10^24 kg - about that of the earth - would have a lifetime of ~5.75x10^50 years) So if there's a 1-20 Earth-mass black hole out there, it hasn't evaporated from anything appreciably larger to get to that point. 0: http://xaonon.dyndns.org/hawking/ http://xaonon.dyndns.org/hawking/
      • raducu 7y ago
        There go my hopes humanity could use this to convert mass to energy. How long would we have to wait for it to evaporate before we could use it for energy production?
    • deleted 7y ago
• tlb 7y ago
  How can you tell for sure whether something is a black hole or a regular rock of the same mass, when you're too far away to resolve the size of the object in a telescope? Do you have to send a probe close and throw something in it?
  • SiempreViernes 7y ago
    I’d say occultation observations, ie looking closely when it passes in front of a star, would allow you to prove things one way or another given the huge difference in density and radius.
    • sliken 7y ago
      Yes, but presumably it's paste Neptune. Even if it's between the mass of earth (9mm) and jupyter (3M) we aren't going to be able to notice a direct occultation. However a lensing event seems possible, it greatly increases the effective radius of detection and is much more distinctive. Not sure what the smallest lensing event witnessed is, all the ones I'm aware of were a solar mass or more.
      • verytrivial 7y ago
        The first paragraph of the article is all over this lensing as a way to explain ultra-short crossing times from the OGLE experiment running in Poland. Reference [6] is titled "Constraints on Earth-mass primordial black holes from OGLE 5-year microlensing events [...]" so there's my weekend reading sorted.
      • SiempreViernes 7y ago
        How does that work, aren't distant stars point like? I guess the bigger problem is the shadow will be very thin and we're unlikely to correctly guess where it lands.
        • sliken 7y ago
          Right, stars are (effectively) point sources light. But if you take images of stars like the LSST is where you can get the entire sky every few days you'll find anomalous stars that weren't on previous exposures. I don't know the physics enough to know if a small (earth to neptune mass) blackhole could redirect enough star lights to detectable by an earth (or earth orbit) telescope. With a huge database containing the time series of the sky you can start searching for unknown objects that stick out because they are a change from the previous exposures for that part of the sky. With enough data mining of those previous exposures you could find likely candidates and get telescope time to check out where you expect it to be next. This is similar to how things like Oumuamua and 2I/Borisov were found.
• rapsey 7y ago
  I apologize in advance for the dumb question. How is an earth mass black hole formed? I thought they form from collapsing large stars.
  • opmac 7y ago
    Primordial black holes were formed during the big bang. That's the only way we think such objects could form.
    • dr_dshiv 7y ago
      What mechanism could create them? By the time there was matter, I thought the only pressure forces were ambient light and baryonic acoustic waves, neither of which should be strong enough...
      • knzhou 7y ago
        You're right that there is no mechanism to make primordial black holes in the standard theory. That's because they're new, separate things, so to have them, you of course need to add in new ingredients. They can be created by the collision of topological defects in the early universe, which in turn can be created in phase transitions during the cooling of the universe, like imperfections in quickly frozen ice. Or they can be created by simple collapse following inflation, if inflation is modified to create large inhomogeneities.
      • ben_w 7y ago
        You don’t need to matter to create a black hole, a Kugelblitz black hole is made entirely of light.
        • dr_dshiv 7y ago
          Fascinating! But, if that's the case, the densities of light after the big bang would have created endless numbers of these?
• Apocryphon 7y ago
  I am reminded of a tale from Yukinobu Hoshino's science fiction anthology-series 2001 NIGHTS, which had a then-tenth planet named Lucifer, with a retrograde orbit and composed of antimatter- a former sun that collapsed not into a black hole, but a gas giant made of antimatter, left over from the Big Bang. https://arche-arc.blogspot.com/2018/11/mythcomics-lucifer-rising-2001-nights.html https://arche-arc.blogspot.com/2018/11/mythcomics-lucifer-ri... Were such theories about a hypothetical planet beyond Pluto already existent when this series was created, back in the mid-'80s?
  • golemotron 7y ago
    Out of curiosity, would we know if a random planet or star system was made of antimatter rather than matter? Is there a spectral difference? Would gamma radiation from interaction with any local matter be the only indicator?
    • michaelmrose 7y ago
      We are constantly interacting with rocks of various sizes and thd small amounts of hydrogen in even nearly empty space. Presumably an antimatter planet would be also only much more violently and would by now be gone.
      • saagarjha 7y ago
        Or be constantly flashing if it wasn’t.
      • golemotron 7y ago
        Is there enough in the ISM (interstellar medium) to have made antimatter star systems impossible over the long term?
        • simcop2387 7y ago
          I don't enough to destroy anything that existed and was massive. But it would be giving off the gamma rays from collisions and we haven't been detecting them.
• dingo_bat 7y ago
  I thought planet 9 was Pluto. Kind of sad to have kicked Pluto out of the club. It had the best name out of all our planets.
• ginko 7y ago
  Very interesting. I guess having a stable black hole like that in our solar system would be an incredible opportunity to send a probe and check our current understanding of physics. If anything it'd be a lot more valuable then just finding another rock in space.
  • est 7y ago
    The odds of finding blackholes everywhere in the universe suddenly increased?
    • Simon_says 7y ago
      Unless there's some unknown effect of having a black hole that makes life more likely to appear when PBH orbit the star, in which case it might decrease estimates of the frequency of life in the universe. It's theorized that the existence of Jupiter played a role in clearing out the inner solar system of kinetic kill vehicles, helping create a stable environment for life to evolve on Earth.
  • jessriedel 7y ago
    A planet-mass black hole in our solar system would be in the top five most revolutionary discovery in physics of all time. It is hard to overstate how insane this would be.
• jcims 7y ago
  Wouldn't we expect such a black hole to slingshot dust and other material to some non-negligible percentages of the speed of light? Wouldn't some of that eventually hit the earth's atmosphere? What would that look like? Tunguska?
  • aruggirello 7y ago
    Not really, it would just form a (tiny) accretion disk. Dust and other material would fall into it, emit gamma rays and be gone forever. It's a black hole.
    • Simon_says 7y ago
      Or both. Accretion disks can shoot a tiny bit of matter out the poles while most falls in. IIRC, the dynamics that cause this effect are not well understood.
  • mnw21cam 7y ago
    What mechanism would act to slingshot material to such high speeds?
    • jcims 7y ago
      Basically just momentum transfer from a gravitational assist.
      • mnw21cam 7y ago
        That wouldn't get anything up to relativistic speeds. The universal rule of slingshot manoeuvres is that you depart from the slingshotting body at the same speed you approached it, just in a different direction (in the slingshotting body's frame of reference). Therefore, the maximum velocity gain you can achieve with a slingshot is governed by the velocity of the slingshotting body - the black hole. Which, as far out in the extremities of the solar system that it is, is not very fast.
        • 7y ago
• moconnor 7y ago
  My favourite part of this paper is the 1:1 scale image of the posited black hole in the appendix...
  • eganist 7y ago
    Page 5 of the pdf (https://arxiv.org/pdf/1909.11090v1.pdf https://arxiv.org/pdf/1909.11090v1.pdf) for anyone wondering.
    • tqkxzugoaupvwqr 7y ago
      Where is the scale bar? If the page is not printed in the right dimensions or displayed 1:1 on a screen, the figure is wrong.
      • MPSimmons 7y ago
        The white horizontal edge bottom of the page is 8.5", and the white vertical edge of the page is 11".
        • dkersten 7y ago
          Pff not when I print it on A4.
          • spacehome 7y ago
            pdfs literally include their actual size in metadata in the document itself. Most printers will complain at least a little bit if you try to print it on the wrong size paper. This paper is : 215.9 × 279.4 mm (Letter, portrait)
      • ubercow13 7y ago
        Isn’t the page size specified in the PDF?
• aruggirello 7y ago
  A PBH in our Solar System would quickly become a very popular target for science, allowing us to test both relativity theory and quantum physics at an unprecedented level. And who knows, we might even be able to use it as a slingshot for interstellar travel, or as a gravitational lens - that would be great! Edit: so, how do we locate it exactly?
  • intarga 7y ago
    What decides how good a slingshot something is isn't its density or mass (provided the mass >> than that of the object being slingshot), but rather its velocity relative to the sun. Planet 9 travels very slowly relative to the sun, and so is a poor slingshot, regardless of its density.
  • danbruc 7y ago
    It took New Horizons about ten years to reach Pluto and this black hole would be on the order of ten times further away from the sun than Pluto. We would of cause still point all kinds of instruments at it from Earth but we would not be able to fly circles around it and throw stuff into it any time soon.
    • sliken 7y ago
      Actually I believe new horizons had a pretty primitive propulsion system and achieved most of it's delta V from a sling shot around jupiter. More recent solar sails and plasma based propulsion systems have achieves significant improvements since then. If it was a priority I don't see why would couldn't go 10x as far within in the next decade.
    • red75prime 7y ago
      Nuclear pulse engine can significantly cut the time.
  • thirdhaf 7y ago
    With regards to how you locate it, the paper proposes looking at existing data from FERMILAT, a gamma ray telescope which could possibly pick up anihilations from a dark matter cloud surrounding such a black hole. Since the object itself is so tiny (I’ve never seen a 1:1 scale figure in an astronomy paper before) you need to detect its presence in some other way.
• wruza 7y ago
  PBH is a greatest component of alchemy, a philosopher's stone. If you mix one with a nearby neutron star in good proportions, you can get lots of gold. https://phys.org/news/2017-08-theory-heavy-elements-primordial-black.amp https://phys.org/news/2017-08-theory-heavy-elements-primordi...
• henearkr 7y ago
  Some potentially interesting uses for it: - definitive sink to send all of our nuclear waste (it would be the /dev/null of the Solar System) - gravitational energy generator (limitless, until we have no more mass to throw in)
  • johndunne 7y ago
    A /dev/null for the solor system would indeed be an awesome feature :) Though the most dangerous part of this would be the risk of loading the material onto a rocket. Sigh.
    • henearkr 7y ago
      Or maybe very dangerous physics experiments would be arranged to occur in space in a collision trajectory with Devnull, so that it would then be automatically annihilated if it went wrong... Probably the more interesting use is that of an energy source!
      • qubex 7y ago
        Let’s set up a petition to name the (hypothetical) primordial black hole at the nether edges of the Solar System “Devnull”!
  • Chris2048 7y ago
    There was a story like that called "iHole", but it appears to have disappeared from the 'net..
    • henearkr 7y ago
      Is it related to that? https://www.urbandictionary.com/define.php?term=iHole https://www.urbandictionary.com/define.php?term=iHole
      • Chris2048 7y ago
        I don't think so. It was about a product release by an apple-like corp that was a small personal hole that you could use as a garbage bin.
• mugwort13 7y ago
  Pluto is “Planet 9”. https://www.google.com/amp/s/www.news18.com/amp/news/buzz/nasa-chief-has-declared-pluto-a-planet-once-again-2287607.html https://www.google.com/amp/s/www.news18.com/amp/news/buzz/na...
• hsnewman 7y ago
  Wouldn't we see some radiation from dust falling in these primordial black holes?
• batarjal 7y ago
  There a lot of talk about the idea of an Earth mass Primordial Black Hole punching through Earth and the effects of such an event. However, Planet nine is predicted to be about five Earth masses, not one. I don't have a physics degree, but how close would Earth have to get to such an object before the Earth is within that object's Roche limit?
  • deleted 7y ago
    [deleted]
  • taneq 7y ago
    Very close, in astronomical terms. At a guess, no further than the distance from Earth to the Moon, and probably much less. I'd love to see real numbers though. :) Edit: According to https://en.wikipedia.org/wiki/Roche_limit https://en.wikipedia.org/wiki/Roche_limit the Roche limit d = Rm * (2 * MM/Mm)^(1/3) for Rm = radius of the satellite, MM = mass of the primary, and Mm = mass of the secondary. So in this case d = 6380 * (2 * 5/1)^(1/3) = 13,745km. In astronomical terms, very nearly a bulls-eye.
  • semi-extrinsic 7y ago
    The Roche limit depends on the density difference between the two bodies in question. For a black hole (of any size), the density is basically infinite compared to regular planets, so the Roche limit is basically zero. As in, less than one meter. The radius of the event horizon for a black hole even the size of Jupiter is only 2.5 meters.
    • CodesInChaos 7y ago
      The gravity field of a spherical object only depends on its mass and not its density/radius. So for the Roche limit only the density/radius of the object at risk of breaking apart (called minor object on wikipedia) (earth) should matter, not the one of the major object (black hole). Wikipedia gives the formula d=R_m*(2m_M/m_m)^{1/3} which matches that intuition.
      • semi-extrinsic 7y ago
• ryan_j_naughton 7y ago
  It blows my mind to think about sub-stellar mass black holes can exist. As I was ignorant of their theoretical possibility, I thought the lower bound limit to a blackholes mass was the Chandrasekhar limit [1] (or even greater as that simply is the boundary between white dwarves and further collapse to either a neutron star or black hole). To learn that the conditions of the early universe could have create sub-stellar mass black holes means there could be tons of small black holes out there lurking in interstellar space. What would happen if one of them got close enough to our Sun to begin accreting gas from the Sun? - Could it eat the entire Sun and cause our solar system to go dark? - As it gained sufficient mass from the Sun, it would switch from orbiting the Sun to them being a binary system. Would that destabilize the orbits of planets? - Or disturb a ton of Oort cloud bodies and potentially cause tons of comets and raise the risk of impact events? - At what point would the Sun's fusion stop? - Obviously this depends on the binary dance of the 2 bodies, but rapidly the sun would be pulled apart. - Would there be X-rays and particle jets like a micro-version of a quasar? I really hope someone is modeling this! [1] https://en.wikipedia.org/wiki/Chandrasekhar_limit https://en.wikipedia.org/wiki/Chandrasekhar_limit
  • jbattle 7y ago
    My understanding is that mass in a black hole doesn't operate any differently at a distance. So if there was an earth-mass black hole in a tight orbit around the sun, it shouldn't have a significant impact on the orbits of objects in the solar system, even after it consumed the entirety of Sol's mass. Maybe Mercury would get messed up, depending on how tight the orbit is. HOWEVER. Getting a black hole into a tight orbit - I don't know how that might happen. A black hole from outside the solar system would be coming in on a parabolic path past the sun. It would shoot right back out of the solar system. If the BH managed to absorb enough mass from the sun, I would imagine that would throw off it's trajectory enough it could become captured into an orbit. On each subsequent fly by / through the sun, it would capture additional mass. This would reduce the period of the orbit. In a situation like this, you have an increasingly massive object passing through the solar system in an irregular pattern. That can't be good.
  • justfor1comment 7y ago
    Your premise is extremely unlikely to begin with. Let's assume somehow it comes to pass, still the time scales of these phenomenon are on the order of millions of years. If today a blackhole were to start eating the Sun, it would take a couple of million years to finish that meal. Given a max human lifespan of 120 years. You and your next 10^4 generations have nothing to worry about.
• parliament32 7y ago
  The coolest part is the 1:1 scale figure on page 5 of the PDF. I don't think I've ever seen a 1:1 figure in an astronomy paper before.
• WeAreFucked 7y ago
  Well, it seems we are all fucked then.
• deleted 7y ago
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• natcat1 7y ago
  What if it sucks up earth!
• natcat1 7y ago
  What if we all die because of planet 9!!!